U.S. patent application number 14/799796 was filed with the patent office on 2015-11-05 for bonding structure manufacturing method, heating and melting treatment method, and system therefor.
The applicant listed for this patent is AYUMI INDUSTRY CO., LTD.. Invention is credited to Hideyuki ABE, Kazuaki MAWATARI.
Application Number | 20150314385 14/799796 |
Document ID | / |
Family ID | 45401990 |
Filed Date | 2015-11-05 |
United States Patent
Application |
20150314385 |
Kind Code |
A1 |
ABE; Hideyuki ; et
al. |
November 5, 2015 |
BONDING STRUCTURE MANUFACTURING METHOD, HEATING AND MELTING
TREATMENT METHOD, AND SYSTEM THEREFOR
Abstract
A soldering method capable of alleviating positional
displacement between substrates even though a step of removing flux
can be omitted is provided. A temporary bonding agent 55 is applied
onto multiple substrates 50a, 50b, and a heater 33 heats the
substrates while the substrates are temporarily bonded with the
temporary bonding agent 55 interposed therebetween, and before the
solder 54 is melted or while the solder 54 is melted, the temporary
bonding agent 55 is evaporated, and the substrates 50a, 50b are
bonded with solder with the melted solder 54 interposed
therebetween.
Inventors: |
ABE; Hideyuki; (Himeji-shi,
JP) ; MAWATARI; Kazuaki; (Hayam-gun, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AYUMI INDUSTRY CO., LTD. |
Himeji-shi |
|
JP |
|
|
Family ID: |
45401990 |
Appl. No.: |
14/799796 |
Filed: |
July 15, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14275153 |
May 12, 2014 |
9119336 |
|
|
14799796 |
|
|
|
|
13806907 |
Dec 26, 2012 |
8757474 |
|
|
PCT/JP2011/064532 |
Jun 24, 2011 |
|
|
|
14275153 |
|
|
|
|
Current U.S.
Class: |
228/42 |
Current CPC
Class: |
H01L 2224/81815
20130101; H01L 2224/75101 20130101; H01L 24/13 20130101; B23K 35/38
20130101; H01L 2224/13082 20130101; H01L 2224/7515 20130101; H01L
2224/1308 20130101; B23K 31/02 20130101; H05K 3/3436 20130101; H01L
2224/13083 20130101; H01L 2224/81002 20130101; H05K 2203/085
20130101; B23K 3/04 20130101; H01L 2224/75272 20130101; H01L
2224/16227 20130101; H05K 2203/087 20130101; H01L 24/75 20130101;
H05K 13/0465 20130101; Y02P 70/613 20151101; H01L 2224/73204
20130101; B23K 3/082 20130101; B23K 1/206 20130101; H01L 2224/8109
20130101; H01L 2224/83104 20130101; H01L 2224/81014 20130101; H01L
2224/81805 20130101; B23K 1/0016 20130101; Y02P 70/50 20151101;
B23K 1/008 20130101; H01L 2224/81193 20130101; H01L 2224/81019
20130101; H01L 2224/81054 20130101; H01L 2224/81907 20130101; B23K
2101/40 20180801; H01L 2224/81211 20130101; H01L 24/16 20130101;
H01L 2224/13116 20130101; H01L 2224/13164 20130101; H01L 2224/32225
20130101; H01L 2924/01322 20130101; H01L 2224/16225 20130101; H01L
2224/81011 20130101; B23K 1/20 20130101; B23K 3/0607 20130101; H01L
2224/13111 20130101; H01L 2224/13155 20130101; H05K 3/305 20130101;
H05K 2203/083 20130101; H01L 24/81 20130101; H01L 2224/81054
20130101; H01L 2924/00012 20130101; H01L 2224/83104 20130101; H01L
2924/00014 20130101; H01L 2224/1308 20130101; H01L 2924/00012
20130101; H01L 2224/13155 20130101; H01L 2924/00014 20130101; H01L
2224/13164 20130101; H01L 2924/00014 20130101; H01L 2224/13116
20130101; H01L 2924/0105 20130101; H01L 2924/00014 20130101; H01L
2224/13111 20130101; H01L 2924/01047 20130101; H01L 2924/00014
20130101; H01L 2224/73204 20130101; H01L 2224/16225 20130101; H01L
2224/32225 20130101; H01L 2924/00 20130101; H01L 2924/01322
20130101; H01L 2924/00 20130101 |
International
Class: |
B23K 3/06 20060101
B23K003/06; B23K 3/08 20060101 B23K003/08; B23K 35/38 20060101
B23K035/38; B23K 3/04 20060101 B23K003/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 28, 2010 |
JP |
2010146337 |
Jul 23, 2010 |
JP |
2010166448 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. (canceled)
12. (canceled)
13. (canceled)
14. (canceled)
15. (canceled)
16. (canceled)
17. (canceled)
18. (canceled)
19. (canceled)
20. (canceled)
21. (canceled)
22. (canceled)
23. (canceled)
24. (canceled)
25. (canceled)
26. A heating and melting treatment system for forming a
heat-melting material by heating a member with said heat-melting
material attached and performing heating and melting treatment on
said heat-melting material, the heating and melting treatment
system comprising: an application unit for applying said
heat-melting material onto the member, and applying a temporary
bonding agent onto a surface of the member in order to temporarily
bond said heat-melting material; a heating unit for heating the
member with said heat-melting material temporarily bonded with said
temporary bonding agent interposed therebetween; and a providing
unit for providing carboxylic acid vapor to the member in a
chamber, wherein before said heat-melting material is melted or
while said heat-melting material is melted, the heating unit
evaporates said temporary bonding agent in the chamber in which
temporarily enhances a vacuum degree so that said temporary bonding
agent is easily evaporated, and on the other hand, the heating unit
heats the member so as to form said heat-melting material without
flux in an atmosphere including the carboxylic acid vapor.
27. The heating and melting treatment system according to claim 31,
wherein said heat-melting material is a solder material or a
eutectic-bonding agent.
28. The heating and melting treatment system according to claim 31,
wherein said temporary bonding agent is a non-reducing organic
agent.
29. The heating and melting treatment system according to claim 33,
wherein said temporary bonding agent has a boiling point of 100
degrees Celsius to 350 degrees Celsius at a pressure of
1.times.10.sup.2 to 1.times.10.sup.5 Pa.
30. The heating and melting treatment system according to claim 33,
wherein said temporary bonding agent is at least one non-reducing
organic agent selected from isobornyl cyclohexanol, terpineol, and
propylene glycol phenyl ether.
31. A bonding structure manufacturing system for manufacturing a
bonding structure by bonding a plurality of members with a
heat-melting material interposed therebetween, the bonding
structure manufacturing system comprising: an application unit for
applying a temporary bonding agent onto the bonded members with the
heat-melting material being formed on at least one of the plurality
of bonded members; a heating unit for heating the plurality of
bonded members temporarily bonded while the plurality of bonded
members are stacked with said temporary bonding agent interposed
therebetween; and a providing unit for providing carboxylic acid
vapor to the plurality of bonded members in a chamber, wherein
before the heat-melting material is melted or while the
heat-melting material is melted, the heating unit evaporates said
temporary bonding agent in the chamber in which temporarily
enhances a vacuum degree so that said temporary bonding agent is
easily evaporated, and on the other hand, the heating unit heats
the bonded members so as to bond the bonded members without flux in
an atmosphere including the carboxylic acid vapor.
32. The bonding structure manufacturing system according to claim
36, wherein said heat-melting material is a solder material or a
eutectic-bonding agent.
33. The bonding structure manufacturing system according to claim
36, wherein said temporary bonding agent is a non-reducing organic
agent.
34. The bonding structure manufacturing system according to claim
38, wherein said temporary bonding agent has a boiling point of 100
degrees Celsius to 350 degrees Celsius at a pressure of
1.times.10.sup.2 to 1.times.10.sup.5 Pa.
35. The bonding structure manufacturing system according to claim
38, wherein said temporary bonding agent is at least one
non-reducing organic agent selected from isobornyl cyclohexanol,
terpineol, and propylene glycol phenyl ether.
Description
TECHNICAL FIELD
[0001] The present invention relates to a bonding structure
manufacturing method, a heating and melting treatment method, and a
system therefor for bonding multiple bonded members with a
heat-melting material such as solder and eutectic-bonding insert
metal interposed therebetween.
BACKGROUND ART
[0002] Techniques for manufacturing a bonding structure by bonding
multiple bonded members with solder or bonding multiple bonded
members with eutectic-bonding, with solder such as solder bumps or
solder sheet or a eutectic-bonding insert metal interposed
therebetween are widely used in semiconductor implementation steps.
For example, in a semiconductor implementation step, a technique
for bonding an organic substrate and a semiconductor substrate with
solder with solder bumps interposed therebetween and a technique
for bonding a semiconductor substrate and a semiconductor chip with
solder with solder bumps interposed therebetween are employed.
[0003] For example, when semiconductor substrates (semiconductor
chips) are bonded with solder, it is necessary to remove an oxide
film on the surface of the solder bump in order to melt the solder
bump and bond multiple substrates with solder. In order to do this,
multiple substrates are stacked and heated while a rosin-based
reducing organic agent, which is called "flux", is applied to the
surface of the substrate. As a result, preferable solder bonding is
made while the oxide film on the surface of the solder bump is
reduced and removed by the flux. After the solder bonding is made,
the flux is removed by cleaning treatment such as solution cleaning
and ion etching.
[0004] However, in recent years, the decrease in the size of the
solder bump structure makes it difficult to remove the flux. In
particular, when the pitch interval between adjacent solder bumps
or the diameter of the solder bump becomes several dozens of .mu.m
or less, it is difficult to sufficiently remove the flux. The flux
that could not be removed makes flux residue. Due to the effect of
chlorine included in the flux, the flux residue may cause
insulation failure, which is called migration, between adjacent
electrode structures (solder bumps). In a step of finally filling
an underfill resin between substrates, the flux residue makes it
impossible to sufficiently fill the underfill resin, which makes
clearance that is called void.
[0005] On the other hand, a method for omitting cleaning treatment
using flux-less solder bonding (cleaning-less method) is actually
used as a method for eliminating the effect of the flux residue.
More specifically, carboxylic acid vapor such as formic acid is
introduced into a chamber, and the oxide film on the surface of the
solder bump is reduced by this carboxylic acid, so that this makes
it possible to make solder bonding without using any flux (Cited
documents 1, 2).
[0006] However, flux-less solder bonding raises a new problem in
that it is likely to cause positional displacement between
substrates. More specifically, as described above, when the flux is
used, retaining force (stack force) occurs due to the flux residing
between the multiple substrates, and this retaining force prevents
the positional displacement of the substrates from one another. In
contrast, with the flux-less solder bonding, there is no flux
between the substrates, and the retaining force (stack force)
cannot be given between the substrates. For this reason, in the
cleaning-less method based on the flux-less solder bonding, it is
likely to cause positional displacement between substrates, and
this imposes limitation on cases where the cleaning-less method can
be applied. In particular, when the substrates are bonded with
solder with the solder bumps on the substrates, a positioning
accuracy may be required to be about 1 to 2 .mu.m, and therefore,
it is difficult to apply the cleaning-less method, which is likely
to cause positional displacement. Similar problems may occur with
eutectic-bonding.
[0007] Further, the positional displacement causes the problem not
only when the substrates are bonded but also when a solder material
is fixed onto a substrate and solder bumps are formed, for
example.
CITATION LIST
Patent Literature
Patent Literature 1: Japanese Patent Application Laid-Open No.
11-233934
Patent Literature 2: Japanese Patent Application Laid-Open No.
2001-244618
SUMMARY OF INVENTION
Technical Problem
[0008] The present invention is to solve the problem concerning the
conventional techniques as described above. More specifically, the
present invention is to provide a bonding structure manufacturing
method and a manufacturing system capable of alleviating the
positional displacement between multiple bonded members even though
cleaning treatment can be omitted when a bonding structure is
manufactured by bonding multiple bonded members with each other
with a heat-melting material interposed therebetween.
[0009] In addition, the present invention is to provide a heating
and melting treatment apparatus and a heating and melting treatment
system capable of alleviating positional displacement in formation
of solder when a solder material is subjected to heating and
melting treatment and solder formation such as a solder bump is
made.
Solution to Problem
[0010] (1) A bonding structure manufacturing method for
manufacturing a bonding structure by bonding a plurality of bonded
members with a heat-melting material interposed therebetween
includes: a step of preparing the bonded members with the
heat-melting material being formed on at least one of the plurality
of bonded members; a temporary bonding step for applying an organic
agent onto surfaces of the plurality of bonded members facing each
other, thereby temporarily bonding the plurality of bonded members
with the organic agent interposed therebetween; a bonding step for
melting the heat-melting material, thereby bonding the plurality of
bonded members with the heat-melting material interposed
therebetween; and an evaporation step for evaporating the organic
agent by heat application before or after the bonding step.
[0011] (2) A bonding structure manufacturing system for
manufacturing a bonding structure by bonding a plurality of members
with a heat-melting material interposed therebetween includes: an
application unit for applying a temporary bonding agent, which is a
non-reducing organic agent, onto the bonded members with the
heat-melting material being formed on at least one of the plurality
of bonded members; a heating unit for heating the plurality of
bonded members temporarily bonded while the plurality of bonded
members are stacked with the temporary bonding agent interposed
therebetween; and a providing unit for providing carboxylic acid
vapor to the plurality of bonded members, wherein before the
heat-melting material is melted or while the heat-melting material
is melted, the heating unit evaporates the temporary bonding agent,
and on the other hand, the heating unit heats the bonded members so
as to bond the bonded members without flux in an atmosphere
including the carboxylic acid vapor.
[0012] (3) A heating and melting treatment method for forming a
solder by heating a member with a solder material attached and
performing heating and melting treatment on the solder material
includes: a temporary bonding step for attaching the solder
material onto the member, applying an organic agent onto a surface
of the member, and temporarily bonding the solder material with the
organic agent interposed therebetween; an evaporation step for
evaporating the organic agent before the solder material is melted
or while the solder material is melted; and a forming step for
forming a solder by melting the solder material.
[0013] (4) A heating and melting treatment system for forming a
solder by heating a member with a solder material attached and
performing heating and melting treatment on the solder material
includes: an application unit for applying the solder material onto
the member, and applying an organic agent onto a surface of the
member in order to temporarily bond the solder material; a heating
unit for heating the member with the solder material temporarily
bonded with the temporary bonding agent interposed therebetween;
and a providing unit for providing carboxylic acid vapor to the
member, wherein before the solder material is melted or while the
solder material is melted, the heating unit evaporates the
temporary bonding agent, and on the other hand, the heating unit
heats the member so as to form a solder without flux in an
atmosphere including the carboxylic acid vapor.
Advantageous Effects of Invention
[0014] According to the present invention, when a bonding structure
is manufactured by bonding multiple bonded members with each other
with solder, the positional displacement between multiple bonded
members can be alleviated even though the cleaning treatment can be
omitted. When the solder is formed, the positional displacement of
the solder material can be alleviated.
BRIEF DESCRIPTION OF DRAWINGS
[0015] FIG. 1 is a schematic configuration diagram illustrating a
bonding structure manufacturing system according to a first
embodiment of the present invention.
[0016] FIG. 2 is a diagram illustrating an example of a substrate
used in a bonding structure manufacturing method according to the
first embodiment of the present invention.
[0017] FIG. 3 is a diagram illustrating a first example of a
substrate different from FIG. 2.
[0018] FIG. 4 is a diagram illustrating a second example of a
substrate different from FIG. 2.
[0019] FIG. 5 is a diagram illustrating a subsequent step for the
substrate of FIG. 2 according to the first embodiment of the
present invention.
[0020] FIG. 6 is a diagram illustrating a step subsequent to FIG. 5
according to the first embodiment of the present invention.
[0021] FIG. 7 is a diagram illustrating a temperature condition and
a vacuum degree condition according to the first embodiment of the
present invention.
[0022] FIG. 8 is a diagram illustrating a step subsequent to FIG. 6
according to the first embodiment of the present invention.
[0023] FIG. 9 is a diagram illustrating a step subsequent to FIG. 8
according to the first embodiment of the present invention.
[0024] FIG. 10 is a diagram illustrating a step subsequent to FIG.
9 according to the first embodiment of the present invention.
[0025] FIGS. 11(a) and 11(b) are diagrams illustrating an example
of application of a temporary bonding agent according to a second
embodiment of the present invention.
[0026] FIG. 12 is a diagram illustrating heating and melting
treatment according to a fourth embodiment of the present
invention.
DESCRIPTION OF EMBODIMENTS
[0027] Embodiments of the present invention will be hereinafter
explained with reference to the appended drawings. In the
explanation about the drawings, the same elements are denoted with
the same reference numerals, and repeated explanation thereabout is
omitted. The ratios of the sizes in the drawings are exaggerated
for the sake of explanation, and may be different from the actual
ratios.
[0028] A bonding structure manufacturing technique of the present
invention relates to a technique for manufacturing a bonding
structure by bonding (in particular, solder bonding or
eutectic-bonding) multiple bonded members with a heat-melting
member (such as solder or insert metal) interposed
therebetween.
First Embodiment
[0029] A bonding structure manufacturing technique of the first
embodiment of the present invention relates to a technique for
manufacturing a bonding structure by bonding multiple bonded
members with solder or bonding multiple bonded members with
eutectic-bonding. This bonding structure manufacturing technique
can also be used for mechanical solder bonding, but preferably, the
bonding structure manufacturing technique is a technique for
bonding substrates with each other, bonding chips with each other,
or bonding a substrate and a chip, with solder bonding, and is to
electrically connect electrode structures of a pair of substrates
with each other, electrically connect electrode structures of chips
with each other, and electrically connect an electrode structure of
a substrate and an electrode structure of a chip, with solder
bonding.
[0030] It should be noted that the substrate may be an organic
substrate such as a print substrate, and may be semiconductor
substrate and a dielectric substrate such as a silicon substrate or
a compound semiconductor substrate. The chip may be a semiconductor
chip or a dielectric chip. Hereinafter, an example of a case where
semiconductor substrates are bonded with each other with solder
bumps interposed therebetween will be explained.
[0031] The bonding structure manufacturing technique according to
the present embodiment includes forming electrode structures
including solder bumps or the like on multiple semiconductor
substrates, applying an organic agent onto the semiconductor
substrates, and temporarily bonding the substrates with this
organic agent. Then, within a chamber, this organic agent is
evaporated before the solder is melted or while the solder is
melted, so that the organic agent is made into a solder
bonding.
[0032] In particular, in the present embodiment, although the
cleaning-less method based on the flux-less solder bonding is
employed to reduce an oxide film of solder by introducing
carboxylic acid into the chamber, non-flux organic agent, i.e., a
temporary bonding agent which is a non-reducing organic agent, is
applied to the substrates and the substrates are temporarily bonded
before the substrates are placed into the chamber. As described
above, instead of using the flux, a dedicated temporary bonding
agent for giving retaining force (stack force) between the
substrates is used to prevent positional displacement of the
substrates, and meanwhile, before the reducing treatment of the
oxide film with the carboxylic acid, or at the same time as the
reducing treatment, the temporary bonding agent is evaporated, and
thereafter the substrates are bonded with each other.
[0033] According to the above configuration, the present invention
alleviates positional displacement between multiple bonded members
even though the cleaning treatment can be omitted.
[0034] FIG. 1 is a diagram illustrating a schematic configuration
of a bonding structure manufacturing system according to the
present embodiment.
[0035] A bonding structure manufacturing system 1 is a substrate
soldering system for bonding substrates with each other. When
roughly divided, the manufacturing system 1 mainly includes a
temporary bonding apparatus 20 and a solder melting apparatus
30.
[0036] The temporary bonding apparatus 20 includes a dispenser 21
and an alignment mechanism 22. The dispenser 21 is an application
unit for applying a temporary bonding agent, which is a
non-reducing organic agent, onto a substrate surface formed with
solder such as solder bumps. When the organic agent is applied, the
organic agent can be applied on the entire surface of the substrate
in a planar manner, or may be applied dispersedly in spots manner.
In the present embodiment, however, the organic agent is applied in
a planar manner. The alignment mechanism 22 is positioning means
for positioning electrode structures of substrates so as to cause
the multiple substrates to face each other to sandwich the applied
temporary bonding agent, and temporarily bonding the substrates.
The temporary bonding apparatus 20 is the same as an apparatus
called a flip chip bonder, except that the applied organic agent is
not a flux agent, and therefore, the temporary bonding apparatus 20
will not be explained in detail.
[0037] On the other hand, the solder melting apparatus 30 includes
a chamber 31, a carboxylic acid providing unit 32, and a heater 33
within the chamber 31. Substrates that have been temporarily bonded
by the temporary bonding apparatus 20 are conveyed into the chamber
31. The providing unit 32 provides carboxylic acid vapor into the
chamber 31 with predetermined timing. However, in some cases, the
treatment can be made not in the chamber 31 but in an open
environment.
[0038] The providing unit 32 includes a carboxylic acid vapor
providing system 34 and a valve 35 that is opened and closed with
predetermined timing. The providing system 34 mixes carrier gas
such as reducing gas such as hydrogen or carbon monoxide or
non-oxidizing gas such as nitrogen with carboxylic acid vapor, and
introduces the carrier gas mixed with the carboxylic acid vapor
into the chamber 31. For example, the providing system 34 includes
a sealed container 36 containing carboxylic acid liquid and a
carrier gas providing tube 38 providing the carrier gas via a valve
37. The carrier gas providing tube 38 generates bubbles in the
sealed container 36 (bubbling). However, the providing unit 32 may
be anything as long as it can provide the carboxylic acid into the
chamber 31, and it may have a different configuration from the
present embodiment.
[0039] The heater 33 will be explained. The heater 33 is a heating
unit provided in the chamber 31. Before the solder is melted or
while the solder is melted, the heater 33 evaporates the temporary
bonding agent as well as performs heating treatment in an
atmosphere including the carboxylic acid vapor, and heats
substrates, which are bonded members, in order to achieve flux-less
solder bonding. In particular, before the reducing treatment of the
oxide film of the solder with the carboxylic acid or at the same
time with the reducing treatment, the heater 33 evaporates the
temporary bonding agent. In order to prevent positional
displacement of the substrates, it is preferable not to evaporate
all the temporary bonding agents before the solder is melted, but
when too much temporary bonding agent remains, the surface of the
solder cannot be exposed to the carboxylic acid vapor, which makes
it difficult to perform the reducing treatment of the oxide film.
Therefore, in terms of the reducing treatment, it is desirable to
evaporate the temporary bonding agent before the solder is
melted.
[0040] Further, the solder melting apparatus 30 includes a
discharge pump 39 for discharge and a carboxylic acid collecting
unit (collecting mechanism) 40 attached or provided at the intake
side or the discharge side of the discharge pump 39 so as to
collect the vaporized carboxylic acid. The carboxylic acid
collecting unit 40 may be a filter attached to the intake side or
the discharge side of the discharge pump 39, or may be a scrubber
attached to the discharge side. The solder melting apparatus 30 is
connected via a valve 42 to a nitrogen providing tube 41 for
replacing (purging) the inside with nitrogen atmosphere.
[0041] In the solder melting apparatus 30 having the configuration
as described above, the substrates temporarily bonded with
temporary bonding agent are conveyed into the chamber. Before the
solder is melted, in particular, before the reducing treatment of
the oxide film of the solder with the carboxylic acid or at the
same time with the reducing treatment, the providing unit 32
provides the carboxylic acid vapor and the heater 33 applies heat
in accordance with the type of the temporary bonding agent in order
to evaporate the temporary bonding agent. Except these features,
the detailed configuration is the same as the configuration of a
generally-available solder melting apparatus, and detailed
description thereabout is omitted.
[0042] A conveying robot may be provided to pass substrates between
the temporary bonding apparatus 20 and the solder melting apparatus
30.
[0043] Subsequently, a bonding structure manufacturing method using
the bonding structure manufacturing system according to the present
embodiment, i.e., a soldering method, will be explained.
[0044] First, as shown in FIG. 2, substrates 50a, 50b having solder
bumps formed on the surface thereof (hereinafter collectively
referred to as substrates 50) are prepared. In this case, the
substrate 50 is a semiconductor substrate. The substrate 50
includes a semiconductor substrate main body 51 and an electrode
structure on the substrate main body 51. More specifically, a
copper post 52, a barrier layer 53 on the copper post 52, and a
solder bump 54 formed on the barrier layer 53 are provided on the
semiconductor substrate main body 51. The copper post 52 is a first
protruding portion made of copper (Cu) or copper alloy. The barrier
layer 53 is an under barrier metal for preventing solder component
from diffusing into the copper post 52 when the solder bump 54 is
melted. For example, the barrier layer 53 is a Ni/Pd/Au stacked
layer in which nickel (Ni), palladium (Pd), and gold (Au) are
stacked in this order from the substrate main body 51. In the case
of FIG. 2, the copper post 52 (first protruding portion) is
provided as the electrode portion, but the electrode portion is not
limited to a protruding form. Moreover, the material thereof is not
limited to copper or copper alloy.
[0045] The solder bump 54 is formed with lead-free solder such as
Sn--Ag (tin-silver) solder that does not include any lead (Pb),
lead-including solder such as Pb--Sn solder, or other solder. The
formation of the solder bump 54 itself is the same as conventional
techniques for forming the solder bump 54 with plating, and
therefore, detailed description thereabout is omitted. Unlike the
present embodiment, it may be possible to use an insert metal for
eutectic-bonding instead of the solder bump 54. In this case, the
eutectic-bonding is made such that two types of materials or more
are diffused into each other to cause material movement at a
treatment temperature and alloy reaction is made, so that the
bonding is completed. This is a type of liquid phase diffusion
bonding in which an insert metal and the like is temporarily melted
and dissolved between surfaces to be bonded and thereafter they are
bonded by isothermal solidification using diffusion, and is a
bonding method using eutectic reaction on liquefaction.
[0046] Both of the pair of prepared semiconductor substrates 50 may
be configured as shown in FIG. 2, but the configuration is not
limited thereto. For example, the substrate 50a, which is one of
the substrates, may be configured to be a substrate including a
first electrode portion (for example, copper post) 52, the barrier
layer 53, and the solder bump 54, and on the other hand, the
substrate 50b, which is the other of the substrates, may be
configured to be a substrate without the solder bump 54 as shown in
FIGS. 3 and 4 (FIG. 3). The solder bump 54 and the barrier layer 53
may be omitted from the substrate 50b, which is the other of the
substrates (FIG. 4). In particular, when both of the solder bump 54
and the barrier layer 53 are omitted from the substrate 50b, which
is the other of the substrates, and solder bonding is directly made
with the second electrode portion (copper post 52), the substrates
can be manufactured with less burden. In the present embodiment,
the reducing treatment can be done sufficiently with the carboxylic
acid, and therefore, even when the barrier layer and the solder
bump are omitted from the substrate 50b, which is the other of the
substrates, solder bonding can be directly made with the second
electrode portion
[0047] It should be noted that the bonding structure manufacturing
technique according to the present embodiment is preferably used
for the substrate 50 provided with multiple solder bumps of which
diameter is 100 .mu.m or less while the pitch interval between
adjacent solder bumps is 150 .mu.m or less. However, the substrate
50 is not limited to this case.
[0048] Subsequently, as shown in FIG. 5, a temporary bonding agent
55 is applied onto the substrate 50. The temporary bonding agent 55
is applied onto the surfaces of the multiple substrates 50a, 50b
facing each other (hereinafter referred to as "bonded surfaces").
The bonded surface corresponds to a surface at a side where an
electrode structure such as the solder bump 54 is formed. The
temporary bonding agent may be applied to the bonded surfaces of
both of the multiple substrates 50a, 50b. Alternatively, the
temporary bonding agent may be applied to only the bonded surface
of the substrate 50a, which is only one of the substrates. Even
when the temporary bonding agent is applied to only the bonded
surface of the substrate 50a, which is only one of the substrates,
the temporary bonding agent is interposed between the pair of
substrates 50a, 50b with the substrate 50a being coming into
contact with the substrate 50b, which is the other of the
substrates, so that retaining force (stack force) can be given
between the substrates 50a, 50b.
[0049] In the present embodiment, the temporary bonding agent 55 is
applied in a planar manner onto the substrate 50 which is the
bonded member. When the temporary bonding agent 55 is applied
uniformly in a planar manner as described above, the retaining
force (stack force) increases. In the present embodiment, the
temporary bonding agent 55 is a non-flux organic agent, i.e.,
non-reducing organic agent. In other words, in the present
embodiment, although the flux-less solder bonding is made, the
temporary bonding agent 55 for giving retaining force (stack force)
between the substrates is applied, instead of the flux, onto the
bonded surfaces of the substrates 50. The reason why the
non-reducing organic agent is desirable is because, even if residue
of the organic agent remains, insulation failure called migration
can be prevented from occurring. More specifically, the temporary
bonding agent 55 is desirably an agent that does not include a
component such as chlorine that adversely affects the
substrate.
[0050] The temporary bonding agent 55 may include organic agent and
viscosity modifier (thinning liquid). This is to adjust the
viscosity. The viscosity of the temporary bonding agent 55 is
preferably within a range of 100 to 100000 (30 degrees Celsius
mPaS). More preferably, the viscosity of the temporary bonding
agent 55 is within a range of 1600 to 66000 (30 degrees Celsius
mPaS). This is because, when the viscosity is too high, it becomes
difficult to apply the agent, and on the other hand, when the
viscosity is too low, the retaining force (stack force) between the
substrates is low, which does not provide sufficient temporary
bonding effect.
[0051] As explained later, the temporary bonding agent 55 is
selected from a material that evaporates before the solder bump 54
is melted (before reaching the melting point of the solder), when
the substrates 50 are heated in the chamber 31. In particular, the
temporary bonding agent 55 is selected from a material that
evaporates before the reducing treatment of the oxide film of the
solder with the carboxylic acid vapor or in parallel with the
reducing treatment. More specifically, the boiling point of the
temporary bonding agent 55 is set on the basis of the pressure in
the chamber 31 before the reducing treatment of the oxide film of
the solder and during the reducing treatment and the substrate
temperature during the reducing treatment. When the pressure in the
chamber 31 is considered, the pressure in the chamber 31 is
preferably a pressure of 1.times.10.sup.2 to 1.times.10.sup.5 Pa
before the reducing treatment or during the reducing treatment in
the present embodiment. The reason why this range is preferable is
because, when the pressure is less than 1.times.10.sup.2 Pa, for
example, the substrates may be displaced due to bumping of the
temporary bonding agent 55, and when the pressure is
1.times.10.sup.5 Pa or more, it is the atmospheric pressure or
more. When the range of the substrate temperature is considered,
the substrate temperature range during the reducing treatment is
desirably 100 degrees Celsius to 350 degrees Celsius. The reason
why this kind of temperature range is preferable is because formic
acid such as carboxylic acid used for the reducing treatment begins
to dissolve at about 350 degrees Celsius, and accordingly, it is
desirably 350 degrees Celsius or less, and on the other hand,
depending on the type of the solder, reducing treatment may be done
at about 100 degrees Celsius with the carboxylic acid vapor. When
the pressure range and the substrate temperature range as described
above are considered, the temporary bonding agent 55 desirably has
a boiling point of 100 degrees Celsius to 350 degrees Celsius at a
pressure of 1.times.10.sup.2 to 1.times.10.sup.5 Pa. In general,
depending on the type of the material of the solder, it is possible
to use a different type of organic agent that evaporates before the
reducing treatment or during the reducing treatment (in general,
before the solder is melted or while the solder is melted). More
specifically, Pb-5Sb solder has a melting point of 314 degrees
Celsius, and the solder bonding temperature is about 330 degrees
Celsius to about 350 degrees Celsius. Sn-3.5Ag solder has a melting
point of 221 degrees Celsius, and the solder bonding temperature is
about 230 degrees Celsius to about 250 degrees Celsius. Some
solders have melting points lower than that of Sn-3.5Ag solder.
Therefore, the temporary bonding agent 55 may be selected depending
on the type of the material of the solder.
[0052] More specifically, according to the result of experiment,
the temporary bonding agent 55 desirably includes at least one
non-reducing organic agent selected from isobornyl cyclohexanol,
terpineol, and propylene glycol phenyl ether. The isobornyl
cyclohexanol (MTPH) has a boiling point of 308 degrees Celsius (5%)
313 degrees Celsius (15%) with the viscosity of 65500 (30 degrees
Celsius mPaS). The terpineol (generic name: pine oil component
includes 97% or higher terpin alcohols such as alpha-terpineol,
beta-terpineol, and gamma-terpineol, which are isomers, which are
the main components) has a viscosity lower than that of the
isobornyl cyclohexanol (MTPH), and has a boiling point of 213 to
223 degrees Celsius. The propylene glycol phenyl ether has a
viscosity of 22.7 (25 degrees Celsius mPaS), and has a boiling
point of 243 degrees Celsius (760 mmHg). In particular, in a case
of Sn--Ag, the isobornyl cyclohexanol (MTPH) is preferable.
[0053] The viscosity modifier may be appropriately selected from
those of which viscosities are less those of isobornyl
cyclohexanol, terpineol, and propylene glycol phenyl ether. For
example, 2,4-diethyl-1,5-pentanediol (C.sub.9H.sub.20O.sub.2) may
be used as the viscosity modifier. The ratio of viscosity modifier
added to the undiluted solution of the organic material may be
selected appropriately, but it may be 0 to 90 weight percent.
[0054] It should be noted that the temporary bonding agent 55 may
include multiple types of non-reducing organic agents having
different boiling points from each other. In this case, at least
some of temporary bonding agent components evaporate earlier than
other temporary bonding agent components, so that, in a portion
where the evaporated temporary bonding agent components existed,
the surfaces of the solder bumps are exposed earlier, and the
reducing treatment is started, whereby the solder bonding is made
earlier. On the other hand, all the temporary bonding agents do not
evaporate at a time, and therefore, over a relatively wide
temperature range, the temporary bonding effect can be maintained,
so that this enhances the effect of preventing the positional
displacement. For example, some of the temporary bonding agent
components evaporate before the solder is melted, and the other
temporary bonding agent components evaporate while the solder is
melted, but an agent obtained by mixing these components can be
used as the temporary bonding agent 55.
[0055] Subsequently, after the temporary bonding agent 55 is
applied, the alignment mechanism 22 positions the substrates 50a,
50b with respect to each other by causing the multiple substrates
50a, 50b to face each other to sandwich the temporary bonding agent
55, so that the substrates 50a, 50b are positioned opposite to each
other. As a result, the temporary bonding agent 55 gives the
retaining force (stack force) between the substrates 50a, 50b, and
the substrates 50a, 50b are temporarily bonded to each other.
[0056] Subsequently, as shown in FIG. 6, the temporarily bonded
substrates 50a, 50b are conveyed into the chamber 31. In the
chamber 31, the substrates 50a, 50b are arranged on the heater 33
with, for example, a tray (not shown) interposed therebetween. In
FIG. 6, the pair of substrates 50a, 50b are shown, but, for
example, multiple pairs of substrates, multiple pairs of chips, and
multiple sets of substrates and chips may be conveyed as bonded
members at a time.
[0057] Subsequently, process is performed under temperature
condition and vacuum degree condition as shown in FIG. 7. First, as
shown in FIG. 7, using the pump 39, the chamber 31 is evacuated to
about, for example, 10 to 50 Pa. The degree of evacuation is not
limited to about 10 to 50 Pa, and may be adjusted as necessary.
Then, subsequent to the evacuation processing, or in parallel with
the evacuation processing, the substrates 50a, 50b are heated with
the heater 33, and the substrate temperature is increased.
[0058] Subsequently, the carboxylic acid vapor is introduced into
the chamber 31. By providing the carboxylic acid vapor, the chamber
31 is at about 100 to 10000 Pa. The carboxylic acid vapor is
desirably introduced at least before the temperature of the
substrates 50a, 50b reaches the melting point of the solder. For
example, when the solder is Sn-3.5Ag (melting point of 221 degrees
Celsius), it is heated to about 230 degrees Celsius to 250 degrees
Celsius suitable for soldering, but at about 200 degrees Celsius or
higher, the reducing effect of the carboxylic acid is enhanced, and
the reducing treatment is started. In a case of Pb-5Sn (melting
point of 314 degrees Celsius), it is heated to about 330 degrees
Celsius to 350 degrees Celsius suitable for soldering, but at about
250 degrees Celsius or higher, the reducing effect of the
carboxylic acid is enhanced, and the reducing treatment is
started.
[0059] Then, in the present embodiment, before the reducing
treatment of the oxide film of the solder with the carboxylic acid
vapor or in parallel with the reducing treatment, the temporary
bonding agent 55 is evaporated. More specifically, when the solder
is Sn-3.5Ag, the reducing treatment is performed at around 200
degrees Celsius, e.g., about 180 degrees Celsius to 250 degrees
Celsius, and the solder bonding is made at about 230 degrees
Celsius to 250 degrees Celsius, but before this reducing treatment
or in parallel with the reducing treatment, the temporary bonding
agent 55 is evaporated. Likewise, when the solder is Pb-5Sn, the
reducing treatment is performed at around 250 degrees Celsius,
e.g., about 220 degrees Celsius to 350 degrees Celsius, and the
solder bonding is made at about 330 degrees Celsius to 350 degrees
Celsius, but before this reducing treatment or in parallel with the
reducing treatment, the temporary bonding agent 55 is evaporated.
Even when the solder is made of other materials, before the
reducing treatment of the oxide film of the solder with the
carboxylic acid vapor or in parallel with the reducing treatment,
the temporary bonding agent 55 is evaporated. As shown in FIG. 7,
when the evacuation to about 10 to 50 Pa makes it easy to evaporate
the temporary bonding agent 55. In other words, it is effective to
temporarily enhance the vacuum degree in the chamber 31 so that the
temporary bonding agent 55 easily evaporates.
[0060] As shown in FIG. 8, as the temporary bonding agent 55
gradually evaporates, the solder bump 54 is gradually exposed to
the carboxylic acid vapor. As a result, the oxide film on the
surface of the solder bump 54 is reduced.
[0061] At this occasion, the temporary bonding agent 55 may include
multiple types of non-reducing organic agents having different
boiling points from each other. In this case, at least some of
temporary bonding agent components evaporate earlier than other
temporary bonding agent components. In a portion where the
temporary bonding agent components that evaporated earlier existed,
the reducing treatment is started earlier, and on the other hand,
all the temporary bonding agent components do not evaporate at a
time due to the difference of the boiling points, and therefore,
the temporary bonding effect can be maintained over a relatively
wide temperature range.
[0062] Then, as shown in FIG. 9, the flux-less solder bonding is
made. Before the solder bump 54 is melted, a portion or all of the
temporary bonding agent 55 may be evaporated, or while the solder
bump 54 is melted, the temporary bonding agent 55 may be
evaporated. In terms of preventing the positional displacement, the
temporary bonding agent 55 is desirably evaporated after the solder
bump 54 starts to melt. However, in terms of sufficiently
performing reducing treatment by earlier exposing the surface of
the solder bump 54 to cause the surface of the solder bump 54 to
come into contact with the carboxylic acid vapor, it is desirable
to evaporate a portion or all of the temporary bonding agent before
the solder bump 54 is melted. More specifically, at least a portion
of the temporary bonding agent 55 is evaporated, and the solder
bump 54 is exposed, and in this exposed portion, the oxide film is
reduced and removed. Even when the temporary bonding agent 55 is
completely evaporated before the solder bump 54 is melted, the
solder bonding can be made without any positional displacement.
Then, when the temperature of the substrates 50a, 50b is a solder
bonding temperature (for example, when the solder is Sn-3.5Ag, the
solder bonding temperature is about 230 degrees Celsius to 250
degrees Celsius), the solder in that portion is melted and soldered
(solder bonding). The temporary bonding agent 55 is completely
evaporated, and then the solder bump 54 is completely exposed, and
the reducing treatment is performed, so that the solder bonding is
completely made by sufficiently melting the solder. At this
occasion, the soldering processing (reflow) is completed. If a
large positional displacement can be prevented with the temporary
bonding agent 55, the positional displacement is thereafter
corrected by self-alignment due to the effect of the surface
tension of the solder. When the temporary bonding agent 55 is
evaporated while the solder 54 is melted, the temporary bonding
effect can be maintained until the soldering effect due to the
melted solder 54 is caused. Even when the temporary bonding agent
55 is evaporated before the solder 54 is melted, this reduces the
time from when the temporary bonding agent 55 is completely
evaporated and the temporary bonding effect is lost to when the
soldering processing is completed, and therefore, the positional
displacement of the substrates 50a, 50b can be prevented or
alleviated.
[0063] After the soldering processing (reflow), the substrate
temperature begins to decrease, and the discharge pump 39
discharges the carboxylic acid vapor. The carboxylic acid
collecting unit (collecting mechanism) 40 collects vaporized
carboxylic acid. Thereafter, the inside of the chamber 31 is
replaced (purged) with gas such as nitrogen introduced from the
nitrogen providing tube 41, and thereafter, the bonding structure
of which solder bondings have been completed, i.e., the
solder-bonded substrates 50, are retrieved.
[0064] Subsequently, as shown in FIG. 10, after the step of the
solder bonding, the underfill resin 56 is filled between multiple
substrates, i.e., the substrate 50a and the substrate 50b, for the
retrieved substrates 50 of which solder bondings have been made.
This is to enhance the pasting strength of the solder-bonded
substrates 50 and to protect them. At this occasion, the organic
agent (temporary bonding agent) between the substrate 50a and 50b
have already been evaporated and removed. Therefore, unlike an
ordinary solder bonding using flux, substantially no organic agent
exists between the substrates 50a and 50b, and even after cleaning,
no residue remains. As a result, in the step of filling the
underfill resin between the substrates, generation of clearances
called voids caused by insufficient filling of the underfill resin
due to the residue can be prevented. Even when the organic agent
(temporary bonding agent) does not remain between the substrates
and a small amount of temporary bonding agent remains, insulation
failure called migration can be prevented because the temporary
bonding agent is not rosin reducing organic agent but is
non-reducing organic agent.
[0065] As illustrated in examples explained below, according to the
technique of the present embodiment, when the substrates are bonded
that are formed with solder bumps of which diameter is about
several dozens of .mu.m or of which pitch is about several dozens
of .mu.m, flux-less solder bonding can be made with a positional
displacement of 2 .mu.m or less.
[0066] The bonding structure manufacturing technique of the first
embodiment of the present invention has been explained hereinabove,
but the present invention is not limited to this case, and can be
changed as necessary.
[0067] For example, the temperature condition and the vacuum degree
condition are not limited to what is shown in FIG. 7. For example,
in order to reduce the process time, it is desired to monotonically
increase the substrate temperature from the entry of the substrate
to the reflow as shown in FIG. 7, but it is not limited thereto.
For example, before the substrate temperature reaches the solder
bonding temperature, the reducing treatment may be performed by
maintaining the substrate temperature at a temperature lower than
the solder bonding temperature by about 50 to 80 degrees Celsius
for a certain period of time. Alternatively, the temperature of the
substrate may be controlled by conveying the substrates 50a, 50b
onto the heater 33 or moving the substrates 50a, 50b out of the
heater 33 while the temperature of the heater 33 is maintained at a
certain level.
[0068] According to the present embodiment, the following effects
can be obtained.
[0069] (1) The organic agent 55 evaporates before the solder 54 is
melted or while the solder 54 is melted, and therefore, after the
solder bonding is made, cleaning for removing the organic agent 55
is unnecessary. Therefore, the residue of the organic agent 55 does
not remain, and in particular, when the electrode structure of the
substrate 50a and the electrode structure of the substrate 50b are
bonded with solder, migration and other contaminations do not
occur. In addition, in the step of filling the underfill resin into
the gap, generation of voids caused by insufficient filling of the
underfill resin due to the residue of the organic material can be
prevented.
[0070] (2) Since the residue of the organic agent 55 does not
remain, this can be used for, in particular, the solder bonding of
the substrate having the solder bumps 54 of which diameter is about
several dozens of .mu.m or less and of which pitch between adjacent
solder bumps is about several dozens of .mu.m, and for, in
particular, the fine structure of several .mu.m or less.
[0071] (3) In particular, the flux-less solder bonding is made
using the temporary bonding agent 55 which is non-reducing organic
agent as the organic agent. Therefore, even with the flux-less
solder bonding, the retaining force (stack force) can be given to
the substrates with the temporary bonding agent 55, and the
positional displacement can be prevented. Even if a small amount of
temporary bonding agent remains, migration and other contaminations
do not occur unlike the flux agent.
[0072] (4) In particular, before the reducing treatment of the
oxide film of the solder 54 with the carboxylic acid vapor or in
parallel with the reducing treatment, the temporary bonding agent
is evaporated, and therefore, as the temporary bonding agent 55 is
gradually evaporated, the solder bump 54 is gradually exposed to
the carboxylic acid vapor. Therefore, the temporary bonding agent
55 prevents the positional displacement of the substrates 50a, 50b,
whereas this does not block the reducing treatment with the
carboxylic acid vapor. Even when the temporary bonding agent 55 is
completely evaporated before the solder bump 54 is melted, the
solder bonding can be made without positional displacement. More
specifically, the positional displacement is prevented while the
substrates are conveyed, and with the effect of the surface tension
of the solder due to the melted solder bump 54, the substrates are
self-aligned, and the positional displacement is corrected.
[0073] (5) The vacuum degree in the chamber 31 is temporarily
enhanced so that the temporary bonding agent 55 easily evaporates,
whereby the temporary bonding agent 55 sandwiched by the substrates
50a, 50b having fine structures (52, 53, 54) is likely to
evaporate.
[0074] (6) The temporary bonding agent 55 has a boiling point of
100 degrees Celsius to 350 degrees Celsius at a pressure of
1.times.10.sup.2 to 1.times.10.sup.5 Pa, and therefore during the
reducing treatment or immediately before the reducing treatment,
the temporary bonding agent 55 remains to give the retaining force,
and on the other hand, the reducing treatment is not blocked.
[0075] (7) The temporary bonding agent 55 is at least one
non-reducing organic agent selected from isobornyl cyclohexanol,
terpineol, and propylene glycol phenyl ether, and therefore during
the reducing treatment or immediately before the reducing
treatment, the temporary bonding agent remains to give the
retaining force, and on the other hand, the reducing treatment is
not blocked. Materials causing migration and other contaminations
are not included. Further, the viscosity is appropriate, and a
sufficient retaining force (stack force) can be given.
[0076] (8) When the temporary bonding agent 55 includes multiple
types of non-reducing organic agents having different boiling
points from each other, at least some of temporary bonding agent
components evaporate earlier than other temporary bonding agent
components, so that, in a portion where the evaporated temporary
bonding agent components existed, the reducing treatment can be
started earlier. On the other hand, all the temporary bonding
agents do not evaporate at a time, and therefore, the temporary
bonding effect can be maintained over a relatively wide temperature
range, so that the effect of preventing the positional displacement
is enhanced.
[0077] (9) The temporary bonding agent 55 is diluted by the
viscosity modifier so that the viscosity becomes 1.times.10.sup.2
to 1.times.10.sup.5 mPas, and therefore, while this prevents a
viscosity that is too high to make application impossible, this can
also prevent the viscosity from becoming too low and prevent small
retaining force of the substrates.
[0078] (10) In particular, this is useful for bonding substrates
that are arranged with the solder bumps 54 having diameters of 100
.mu.m or less which are arranged while the pitch interval between
adjacent bumps is 150 .mu.m or less.
[0079] (11) The present embodiment is of a type using the solder
bumps 54, but the oxide film can be reduced sufficiently with the
carboxylic acid vapor, and therefore, one of the pair of the
substrates 50a, 50b may not have the barrier layer 53 and the
solder bump 54, and may have only a copper post (a second
protruding portion made of copper) 52 formed thereon, so that
solder bonding can be made directly. Accordingly, the substrates
50b can be manufactured with less burden.
[0080] (12) In the present embodiment, the temporary bonding agent
55 is applied in a planar manner onto the substrates 50, and
therefore, the amount of temporary bonding agent 55 increases, and
this increases the retaining force (stack force).
Second Embodiment
[0081] Subsequently, the second embodiment of the present invention
will be explained. In the first embodiment, a case where the
temporary bonding agent is applied in a planar manner onto the
substrates has been explained. However, in the second embodiment,
the temporary bonding agent is applied in spots manner onto
multiple positions. Except this feature, the bonding structure
manufacturing technique of the present embodiment is the same as
the first embodiment. Accordingly, the same members as the members
of the first embodiment are also denoted with the same reference
numerals in the present embodiment, and detailed description
thereabout is omitted.
[0082] In the present embodiment, in the temporary bonding
apparatus 20 as shown in FIG. 1, the dispenser 21 dispersedly
applies, in spots manner, the temporary bonding agent which is
non-reducing organic agent onto the substrate surfaces formed with
solder such as solder bump.
[0083] FIGS. 11(a) and 11(b) illustrate an example of a case where
a temporary bonding agent 55 is dispersedly applied in spots
manner. FIG. 11(a) is a top view illustrating a substrate 50a. FIG.
11(b) illustrates substrates 50a, 50b which are temporarily
bonded.
[0084] In the case as shown in FIGS. 11(a) and 11(b), the temporary
bonding agent 55 is applied in spots manner to four corners of a
rectangular substrate (chip). When the flux is applied, the flux
must be applied to the solder surface so that it comes into contact
therewith because it is a primary purpose to reduce and remove the
oxide film on the surface of the solder with the flux. However, in
the present embodiment, the oxide film on the surface of a solder
54 is reduced with the carboxylic acid vapor, and therefore, the
temporary bonding agent 55 is sufficient as long as the temporary
bonding agent 55 simply gives the retaining force (stack force)
between the substrates. Therefore, the temporary bonding agent 55
need not be applied onto the surface of the solder 54 so that it
comes into contact therewith. Therefore, as shown in FIGS. 11(a)
and 11(b), the temporary bonding agent 55 may be applied to the
surface of the solder 54 so that it does not come into contact
therewith.
[0085] The type, temperature condition, vacuum degree condition,
carboxylic acid gas, solder bump diameter, pitch size, and the like
of the temporary bonding agent 55 are the same as those of the
first embodiment.
[0086] Even when the temporary bonding agent 55 is dispersedly
applied in spots manner as described above, the flux-free solder
bonding can be made while suppressing the positional displacement
of the substrates 50a, 50b. Moreover, since the temporary bonding
agent 55 is dispersedly applied in spots manner, the temporary
bonding agent 55 can be easily evaporated. In particular, since the
temporary bonding agent 55 can be applied without coming into
contact with the surface of the solder, the temporary bonding agent
55 does not come into the gaps between the adjacent solder bumps
54, and evaporation and removal can be done easily.
[0087] Further, if the effect of the temporary bonding can prevent
the position of the solder bump 54 from deviating from the position
of the electrode structure (copper post, barrier layer, solder bump
of the other substrate, and the like), small positional
displacement can be self-aligned with the effect of the surface
tension of the solder when the solder bump 54 is melted, so that
the positional displacement is corrected. In particular, the effect
of self-alignment is high in the present embodiment in which the
amount of temporary bonding agent 54 is small.
[0088] In the above explanation, the temporary bonding agent 55 is
applied in spots manner (dots manner). However, the present
embodiment is not limited to this case, and the temporary bonding
agent 55 may be applied in a linear manner (line manner).
Alternatively, instead of dispersedly applying the temporary
bonding agent 55 to multiple spots, the temporary bonding agent 55
may be applied in a spot manner or a line manner.
[0089] According to the present embodiment, not only the effects
(1) to (12) of the first embodiment but also the following effects
can be obtained.
[0090] (13) A sufficient amount of retaining force (stack force)
can be given to the substrate, and the temporary bonding agent is
dispersedly applied in spots manner, and therefore, the temporary
bonding agent can be easily evaporated.
[0091] (14) In particular, when the temporary bonding agent is
applied so as not to be in contact with the surface of the solder,
the temporary bonding agent does not enter into the gaps between
the solder bumps, and evaporation and removal can be done
easily.
Third Embodiment
[0092] In the explanation about the above first and second
embodiments, the temporary bonding agent which is the non-flux
organic agent, i.e., the non-reducing organic agent, is applied as
the temporary bonding agent 55 to the substrates, so that the
substrates are temporarily bonded.
[0093] It is true that in terms of not causing migration and other
contaminations even when a very small amount of temporary bonding
agent 55 remains without being completely evaporated, it is
desirable to use the non-reducing organic agent, which is not the
flux agent, as the temporary bonding agent 55, but the present
invention is not limited to this case.
[0094] More specifically, according to the present invention,
multiple bonded members are temporarily bonded with the organic
agent interposed therebetween, and then, before the solder is
melted, the organic agent is evaporated, and therefore, even if
flux agent is used as the organic agent, it is not necessary to
provide a step of removing the flux by cleaning treatment such as
solution cleaning and ion etching after the solder bonding is made.
Therefore, for example, even when the pitch interval between
adjacent solder bumps or the diameter of the solder bump 54 is
several dozens of .mu.m or less, it is not necessary to consider
the issue of the difficulty of removing the flux. Therefore,
according to the present invention, even if the flux agent is used,
no flux residue is generated after the solder bonding is made, and
therefore, insulation failure called migration can be prevented
from occurring. Finally, in the step of filling the underfill resin
56 into the substrates, generation of clearances called voids
caused by insufficient filling of the underfill resin 56 due to the
flux residue can be prevented.
[0095] As described above, the present invention can be widely
applied, as long as multiple substrates are temporarily bonded with
the organic agent interposed therebetween by applying the organic
agent to the multiple substrates 50a, 50b so that the organic agent
is sandwiched between the multiple substrates 50a, 50b, and the
multiple temporarily bonded members are heated, and before the
solder is melted or while the solder is melted, the organic agent
is evaporated, and the solder is melted in the chamber 31, so that
the multiple substrates are bonded with solder with the solder
interposed therebetween.
Fourth Embodiment
[0096] Subsequently, the fourth embodiment of the present invention
will be explained.
[0097] In the first to third embodiments, the substrate bonding
technique has been explained, but the present invention can also be
applied to solder forming techniques. More specifically, the
present embodiment relates to a heating and melting treatment
method for forming solder bumps on a substrate 50a which is a
member with a solder material 54b attached.
[0098] The solder material 54b is attached onto the substrate 50a
(member), and the temporary bonding agent 55 which is the organic
agent is applied onto the surface of the substrate 50a, and the
position of the solder material 54b is temporarily bonded with the
temporary bonding agent (organic agent) 55 interposed therebetween.
Then, the temporary bonding agent 55 is evaporated before the
solder material 54b is melted or while the solder material 54b is
melted. Then, the solder bumps 54 are formed by melting the solder
material 54b. Even in this case, positional displacement of the
solder material 54b is prevented.
[0099] For this processing a heating and melting treatment system
is provided. This system is the same as the system of FIG. 1. The
system is a heating and melting treatment system for forming solder
by performing the heating and melting treatment on the solder
material 54b by heating the member with the solder material 54b
attached. Further, the system includes the temporary bonding
apparatus 20 for applying the organic agent onto the surface of the
member in order to attach the solder material 54b onto the member
and temporarily bonding the solder material 54b, a heating unit
(solder melting apparatus 30) for heating the member to which the
solder material is temporarily bonded, with the temporary bonding
agent interposed therebetween, and a providing unit for providing
the carboxylic acid vapor to the member, wherein before the solder
material is melted or while the solder material is melted, the
heating unit evaporates the temporary bonding agent, and heats the
member in order to form solder without flux in an atmosphere
including the carboxylic acid vapor.
[0100] Except these features, it is the same as the first to third
embodiments, and detailed description thereabout is omitted.
EXAMPLE
First Example
[0101] Substrates 50a, 50b having a copper post 52, a barrier layer
(Ni/Pd/Au) 53 on the copper post 52, an Sn--Ag solder bump 54
formed on the bather layer 53 formed on silicon substrates (5 mm
square, 25 mm square) were prepared. The pair of substrates 50a,
50b were prepared. It should be noted that the substrates of which
diameter of the solder bump 54 was 100 microns and of which pitch
between adjacent solder bumps (distance between centers) was 250
microns were used.
[0102] The temporary bonding agent was manufactured by diluting the
isobornyl cyclohexanol with viscosity modifier
(2,4-diethyl-1,5-pentanediol). At this occasion, the example is
implemented when the ratio of the viscosity modifier was set at 0
weight percent, 30 weight percent, 50 weight percent, 70 weight
percent, and 90 weight percent. The temporary bonding agent 55 was
applied in a planar manner onto the pair of substrates 50a, 50b.
Then, under the process condition as shown in FIG. 7, the reducing
treatment was performed in the formic acid atmosphere, and the
flux-less solder bonding was made.
[0103] As a result, there was no positional displacement in the
substrates 50a, 50b, and solder bonding was made preferably.
[0104] On the other hand, when the treatment was performed in
nitrogen atmosphere as the comparative example, there was no
positional displacement, but the bonding portion of the solder was
not formed preferably.
Second Example
[0105] Substrates of which diameter of the solder bump 54 was 20
microns and of which pitch between adjacent solder bumps (distance
between centers) was 40 microns were used. The other conditions
were the same as those of the first example. Even in this case, the
positional displacement of the substrates 50a, 50b was 2 .mu.m or
less, and the solder bonding was made preferably.
Third Example
[0106] The same substrates as the first example were temporarily
bonded using the temporary bonding agent manufactured by diluting
the terpineol with the viscosity modifier
(2,4-diethyl-1,5-pentanediol). The example is implemented when the
ratio of the viscosity modifier was set at 0 weight percent, 30
weight percent, 50 weight percent, 70 weight percent, and 90 weight
percent. Even in this case, like the first example, the positional
displacement was small, and the solder bonding was made preferably.
However, the yield slightly decreases as compared with the case of
the first example.
Fourth Example
[0107] The same substrates as the second example were temporarily
bonded using the temporary bonding agent manufactured by diluting
the terpineol with the viscosity modifier
(2,4-diethyl-1,5-pentanediol). Even in this case, like the second
example, the positional displacement was small, and the solder
bonding was made preferably. However, the yield was worse as
compared with the case of the second example.
Fifth Example
[0108] The same substrates as the first example were temporarily
bonded using the temporary bonding agent manufactured by diluting
the propylene glycol phenyl ether with the viscosity modifier
(2,4-diethyl-1,5-pentanediol). The example is implemented when the
ratio of the viscosity modifier was set at 0 weight percent, 30
weight percent, 50 weight percent, 70 weight percent, and 90 weight
percent. Even in this case, the positional displacement was small,
and the solder bonding was made preferably. However, the yield was
worse as compared with the case of the first and third
examples.
Sixth Example
[0109] The same substrates as the second example were temporarily
bonded using the temporary bonding agent manufactured by diluting
the propylene glycol phenyl ether with the viscosity modifier
(2,4-diethyl-1,5-pentanediol). Even in this case, like the second
example, the positional displacement was small, and the solder
bonding was made preferably. However, the yield was worse as
compared with the case of the second and fourth examples.
Seventh Example
[0110] The same temporary bonding agent was dispersedly applied in
spots manner onto the same substrate as the first example at four
locations (four points). At this occasion, with the effect of the
temporary bonding by the temporary bonding agent, the positional
displacement was alleviated, and the solder bonding could be made.
In this example, an experiment was conducted with a sample in which
a small positional displacement of about 20 .mu.m between the
substrates 50a, 50b was made before the solder bonding was made,
but when the effect of the temporary bonding can prevent a large
positional displacement, the positional displacement was solved by
the self-alignment with the effect of the surface tension of the
solder due to the melting of the solder bump 54. Therefore, in
practice, this experiment indicates that, by dispersedly applying
the temporary bonding agent, the positional displacement between
the multiple substrates can be alleviated although the cleaning
treatment can be omitted when the soldering substrate is
manufactured by bonding multiple substrates with each other with
solder.
Eighth Example
[0111] The same temporary bonding agent was dispersedly applied in
spots manner onto the same substrate as the second example at four
locations. Even in this case, the positional displacement between
multiple substrates was alleviated.
Ninth Example
[0112] A temporary bonding agent manufactured by diluting the
terpineol with the viscosity modifier (2,4-diethyl-1,5-pentanediol)
at 0% to 90 weight percent was dispersedly applied to four
locations in spots manner to the same substrates as the first
example. Likewise, the temporary bonding agent was also dispersedly
applied to four locations in spots manner to the same substrates as
the second example. These also alleviated the positional
displacement between the multiple substrates, which was the
practical level.
Tenth Example
[0113] A temporary bonding agent manufactured by diluting the
propylene glycol phenyl ether with the viscosity modifier
(2,4-diethyl-1,5-pentanediol) at 0% to 90 weight percent was
dispersedly applied to four locations in spots manner to the same
substrates as the first example. Likewise, the temporary bonding
agent was also dispersedly applied to four locations in spots
manner to the same substrates as the second example. These also
alleviated the positional displacement between the multiple
substrates, which was the practical level.
[0114] Hereinabove, embodiments suitable for the present invention
have been explained. The present invention is not limited to the
above cases, and addition, deletion, change, and the like can be
made without deviating from the scope of the claims. In the above
explanation, the pair of semiconductor substrates have been
explained as the bonding structures, for example. It is to be
understood that the bonded structures to which the present
invention relates include various kinds of solder-bonded
substrates, solder-bonded chips (flip-chip-bonded chips and the
like), and one obtained by bonding a substrate and a chip. In the
above explanation, use of the solder bumps as solder has been
mainly explained. However, the present invention is not limited to
the cases.
[0115] This application is based on Japanese Patent Application No.
2010-146337 filed on Jun. 28, 2010, and Japanese Patent Application
No. 2010-166448 filed on Jul. 23, 2010, and the entire contents of
the disclosure are incorporated herein by reference.
REFERENCE SIGNS LIST
[0116] 1 bonding structure manufacturing system, [0117] 20
temporary bonding apparatus, [0118] 21 dispenser, [0119] 22
alignment mechanism, [0120] 30 solder melting apparatus, [0121] 31
chamber, [0122] 32 providing unit of carboxylic acid, [0123] 33
heater, [0124] 34 providing system, [0125] 35 valve, [0126] 36
sealed container, [0127] 37 valve, [0128] 38 carrier gas providing
tube, [0129] 39 discharge pump, [0130] 40 carboxylic acid
collecting unit, [0131] 41 nitrogen providing tube, [0132] 42
valve, [0133] 50 (50a, 50b) semiconductor substrate, [0134] 51
semiconductor substrate main body, [0135] 52 copper post (first
protruding portion), [0136] 53 barrier layer, [0137] 54 solder
bump, [0138] 55 temporary bonding agent, [0139] 56 underfill
resin.
* * * * *