U.S. patent application number 13/003996 was filed with the patent office on 2011-05-12 for mounting method and mounting structure for semiconductor package component.
This patent application is currently assigned to PANASONIC CORPORATION. Invention is credited to Arata Kishi, Naomichi Ohashi, Seiji Tokii, Masato Udaka, Atsushi Yamaguchi.
Application Number | 20110108997 13/003996 |
Document ID | / |
Family ID | 43010884 |
Filed Date | 2011-05-12 |
United States Patent
Application |
20110108997 |
Kind Code |
A1 |
Ohashi; Naomichi ; et
al. |
May 12, 2011 |
MOUNTING METHOD AND MOUNTING STRUCTURE FOR SEMICONDUCTOR PACKAGE
COMPONENT
Abstract
A semiconductor package component (3) is mounted on a substrate
(1) in such a manner that an electrode (2) of the substrate (1) and
an electrode of the semiconductor package component (3) are brought
into contact with each other through a joining material (4). A
reinforcing adhesive (5c) is applied between the substrate (1) and
the outer surface of the semiconductor package component (3). Then,
reflow is performed to melt the joining metal (4) with the
reinforcing adhesive (5c) uncured. After the reinforcing adhesive
(5c) is cured, the joining metal (4) is solidified.
Inventors: |
Ohashi; Naomichi; (Hyogo,
JP) ; Yamaguchi; Atsushi; (Osaka, JP) ; Kishi;
Arata; (Osaka, JP) ; Udaka; Masato; (Hyogo,
JP) ; Tokii; Seiji; (Hyogo, JP) |
Assignee: |
PANASONIC CORPORATION
Osaka
JP
|
Family ID: |
43010884 |
Appl. No.: |
13/003996 |
Filed: |
April 19, 2010 |
PCT Filed: |
April 19, 2010 |
PCT NO: |
PCT/JP2010/002800 |
371 Date: |
January 13, 2011 |
Current U.S.
Class: |
257/782 ;
257/E21.499; 257/E23.01; 438/118 |
Current CPC
Class: |
Y02P 70/50 20151101;
H05K 3/3494 20130101; H01L 24/83 20130101; H05K 2203/0545 20130101;
H01L 2924/15311 20130101; H05K 2203/1476 20130101; H05K 2201/10734
20130101; Y02P 70/613 20151101; H01L 2924/0002 20130101; H05K 3/305
20130101 |
Class at
Publication: |
257/782 ;
438/118; 257/E21.499; 257/E23.01 |
International
Class: |
H01L 23/48 20060101
H01L023/48; H01L 21/50 20060101 H01L021/50 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 24, 2009 |
JP |
2009-105757 |
Apr 24, 2009 |
JP |
2009-105758 |
Claims
1. A semiconductor package component mounting method comprising:
mounting a semiconductor package component on a substrate in such a
manner that an electrode of the substrate and an electrode of the
semiconductor package component are brought into contact with each
other through a solidified joining metal; applying a reinforcing
adhesive between a periphery of an area on the substrate where the
semiconductor package component is mounted and an outer surface of
the semiconductor package component in such a manner that the
reinforcing adhesive does not contact the joining metal; and
performing reflow to melt the joining metal while the reinforcing
adhesive is uncured, curing the reinforcing adhesive, and
solidifying the joining metal.
2. The semiconductor package component mounting method according to
claim 1, wherein, in the applying of the reinforcing adhesive, the
reinforcing adhesive is applied so that the reinforcing adhesive
extends from a surface of the semiconductor package component
opposite a surface facing the substrate to the substrate.
3. The semiconductor package component mounting method according to
claim 1, wherein, in the applying of the reinforcing adhesive, the
reinforcing adhesive is applied so that the reinforcing adhesive
extends from an end face of the semiconductor package component to
the substrate, the end face connecting a surface of the
semiconductor package component facing the substrate and a surface
opposite the surface.
4. A semiconductor package component mounting structure in which a
semiconductor package component is mounted on a substrate by
joining an electrode of the substrate to an electrode of the
semiconductor package component with a joining metal, the mounting
structure comprising: a cured reinforcing adhesive which is not in
contact with the joining metal, the reinforcing adhesive extending
from a surface of the semiconductor package component opposite a
surface facing the substrate to the substrate, wherein: the cured
reinforcing adhesive extends over a distance L1 onto the opposite
surface of the semiconductor package component from an end face of
the semiconductor package component and extends over a distance L2
onto the surface of the semiconductor package component facing the
substrate from the end face of the semiconductor package component,
the end face connecting the surface of the semiconductor package
component facing the substrate and the opposite surface; and the
distance L1 over which the reinforcing adhesive extends onto the
opposite surface of the semiconductor package component from the
end face connecting the surface of the semiconductor package
component facing the substrate and the opposite surface is equal to
or greater than the distance L2 over which the reinforcing adhesive
extends onto the surface of the semiconductor package component
facing the substrate from the end face of the semiconductor package
component.
5. The semiconductor package component mounting structure according
to claim 4, wherein the reinforcing adhesive is not in contact with
the joining metal.
6. A semiconductor package component mounting method comprising:
applying a first reinforcing adhesive to a position on a substrate
where a semiconductor package component is to be mounted; mounting
the semiconductor package component on the substrate in such a
manner that an electrode of the substrate and an electrode of the
semiconductor package component are brought into contact with each
other through a solidified joining metal; applying a second
reinforcing adhesive between a periphery of an area on the
substrate where the semiconductor package component is mounted and
an outer surface of the semiconductor package component; and
performing reflow to melt the joining metal and curing the first
and second reinforcing adhesives while the joining metal
solidifies.
7. The semiconductor package component mounting method according to
claim 6, wherein, in the applying of the second reinforcing
adhesive, the second reinforcing adhesive is applied so that the
second reinforcing adhesive extends from a surface of the
semiconductor package component opposite a surface facing the
substrate to the substrate.
8. The semiconductor package component mounting method according to
claim 6, wherein, in the applying of the second reinforcing
adhesive, the second reinforcing adhesive is applied so that the
second reinforcing adhesive extends from an end face of the
semiconductor package component to the substrate, the end face
connecting a surface of the semiconductor package component facing
the substrate and a surface opposite the surface.
9. A semiconductor package component mounting structure in which a
semiconductor package component is mounted on a substrate by
joining an electrode of the substrate to an electrode of the
semiconductor package component with a joining metal, the mounting
structure comprising: a cured first reinforcing adhesive disposed
between the substrate and a surface of the semiconductor package
component facing the substrate; and a cured second reinforcing
adhesive disposed from an end face connecting the surface of the
semiconductor package component facing the substrate and an
opposite surface of the semiconductor package component to the
substrate.
10. The semiconductor package component mounting structure
according to claim 9, wherein the first and second reinforcing
adhesives are not in contact with the joining metal.
11. A semiconductor package component mounting structure in which a
semiconductor package component is mounted on a substrate by
joining an electrode of the substrate to an electrode of the
semiconductor package component with a joining metal, the mounting
structure comprising: a cured first reinforcing adhesive disposed
between the substrate and a surface of the semiconductor package
component facing the substrate; and a cured second reinforcing
adhesive disposed from a surface of the semiconductor package
component opposite the surface facing the substrate to the
substrate.
12. The semiconductor package component mounting structure
according to claim 11, wherein the first and second reinforcing
adhesives are not in contact with the joining metal.
Description
TECHNICAL FIELD
[0001] The present invention relates to a semiconductor package
component mounting method for surface-mounting a semiconductor
package component on a substrate.
BACKGROUND ART
[0002] A semiconductor package component such as a BGA (Ball Grid
Array) component having electrodes formed on the underside is
mounted in one of the process illustrated in FIGS. 17(a) to 17(e)
and the process illustrated in FIGS. 18(a) to 18(d).
[0003] In FIGS. 17(a) and 17(b), a semiconductor package component
3 is mounted on a substrate 1 in such a manner that bump electrodes
4 of the semiconductor package component 3 come into contact with
electrodes 2 on the substrate 1.
[0004] In FIG. 17(c), reflow is performed. In the reflow, the
solder of the bump electrodes 4 melts and the semiconductor package
component 3 moves to a proper position by the self-alignment
effect. Then the substrate and component are cooled to the melting
temperature of the solder or lower to solidify the solder, so that
electrical connection between the semiconductor package component 3
and the substrate 1 is completed.
[0005] In FIG. 17(d), a thermoset resin 5 is injected between the
semiconductor package component 3 and the substrate 1 with a
syringe or the like.
[0006] In FIG. 17(e), the substrate 1 is heated to a temperature
not lower than the curing temperature of the thermoset resin 5 to
cure the thermoset resin 5, thereby mechanically fixing the
semiconductor package component 3 onto the substrate 1.
[0007] The method illustrated in FIGS. 17(a) to 17(e) involves two
heating steps, the reflow in FIG. 17(c) and the heating in FIG.
17(e). In contrast, the process illustrated in FIGS. 18(a) to 18(d)
involves only one heating step.
[0008] In FIGS. 18(a) and 18(b), the thermoset resin 5 is applied
to a position 6 on the substrate 1 where the semiconductor package
component 3 is to be mounted. FIG. 19 illustrates how the thermoset
resin 5 is applied.
[0009] In FIG. 18(c), the semiconductor package component 3 is
mounted on the substrate 1 in such a manner that the bump
electrodes 4 of the semiconductor package component 3 come into
contact with the electrode 2 on the substrate 1. At this point, the
uncured thermoset resin 5 is in contact with the substrate 1 and
the underside of the semiconductor package component 3.
[0010] In FIG. 18(d), reflow is performed. In the reflow, the
solder of the bump electrodes 4 melts. Since the thermoset resin 5
is uncured at this point in time, the semiconductor package
component 3 is moved to the proper position by the self-alignment
effect of the melted solder between the electrodes on the substrate
1 and the electrodes of the semiconductor package component 3.
After the thermoset resin 5 is cured by heating, the temperature
decreases to a temperature not higher than the melting temperature
of the solder to solidify the solder, so that the electrical
connection and mechanical bonding of the semiconductor package
component 3 to the substrate 1 are completed. FIG. 20 illustrates
the completion of the mounting.
CITATION LIST
Patent Literature
[0011] Patent Literature: Japanese Patent Application Laid-Open
Publication No. 11-204568
SUMMARY OF INVENTION
Technical Problem
[0012] The mounting process illustrated in FIGS. 18 to 20 involves
only one heating step. However, the quantity and position of the
thermoset resin 5 to be applied are difficult to adjust, thereby
causing variations in mounting quality.
[0013] Specifically, during the process in which the solder melts
and solidifies, the uncured thermoset resin 5 is in the vicinity of
or in contact with the solder. Therefore, when the application
quantity of the thermoset resin 5 is reduced in order to prevent
some of the uncured thermoset resin 5 from melting and being mixed
with the solidifying solder to degrade the soldering quality, the
strength of the mechanical bonding between the semiconductor
package component 3 and the substrate 1 decreases.
[0014] An object of the present invention is to provide a
semiconductor package component mounting method which can reduce
the number of heating steps, stably maintain the quality of
electrical joining between a semiconductor package component and a
substrate, and ensure a sufficient strength of mechanical bonding
between the semiconductor package component and the substrate.
Solution to Problem
[0015] A semiconductor package component mounting method according
to the present invention includes: mounting a semiconductor package
component on a substrate in such a manner that an electrode of the
substrate and an electrode of the semiconductor package component
are brought into contact with each other through a solidified
joining metal; applying a reinforcing adhesive between the
periphery of an area on the substrate where the semiconductor
package component is mounted and the outer surface of the
semiconductor package component in such a manner that the
reinforcing adhesive does not contact the joining metal; and
performing reflow to melt the joining metal while the reinforcing
adhesive is uncured, curing the reinforcing adhesive, and
solidifying the joining metal.
[0016] A semiconductor package component mounting structure
according to the present invention is a structure in which a
semiconductor package component is mounted onto a substrate by
joining an electrode of the substrate to an electrode of the
semiconductor package component with a joining metal. The mounting
structure includes: a cured reinforcing adhesive which is not in
contact with the joining metal, the reinforcing adhesive extending
from a surface of the semiconductor package component opposite a
surface facing the substrate to the substrate, wherein the cured
reinforcing adhesive extends over a distance L1 onto the opposite
surface of the semiconductor package component from an end face of
the semiconductor package component and extends over a distance L2
onto the surface of the semiconductor package component facing the
substrate from the end face of the semiconductor package component,
the end face connecting the surface of the semiconductor package
component facing the substrate and the opposite surface; and the
distance L1 over which the reinforcing adhesive extends onto the
opposite surface of the semiconductor package component from the
end face connecting the surface of the semiconductor package
component facing the substrate and the opposite surface is equal to
or greater than the distance L2 over which the reinforcing adhesive
extends onto the surface of the semiconductor package component
facing the substrate from the end face of the semiconductor package
component.
[0017] A semiconductor package component mounting method according
to the present invention includes: applying a first reinforcing
adhesive to a position on a substrate where a semiconductor package
component is to be mounted; mounting the semiconductor package
component on the substrate in such a manner that an electrode of
the substrate and an electrode of the semiconductor package
component are brought into contact with each other through a
solidified joining metal; applying a second reinforcing adhesive
between the periphery of an area on the substrate where the
semiconductor package component is mounted and the outer surface of
the semiconductor package component; and performing reflow to melt
the joining metal and curing the first and second reinforcing
adhesives while the joining metal solidifies.
[0018] A semiconductor package component mounting structure
according to the present invention is a structure in which a
semiconductor package component is mounted on a substrate by
joining an electrode of the substrate to an electrode of the
semiconductor package component with a joining metal. The mounting
structure includes: a cured first reinforcing adhesive disposed
between the substrate and a surface of the semiconductor package
component facing the substrate; and a cured second reinforcing
adhesive disposed from an end face connecting the surface of the
semiconductor package component facing the substrate and the
opposite surface of the semiconductor package component to the
substrate.
[0019] A semiconductor package component mounting structure
according to the present invention is a structure in which a
semiconductor package component is mounted on a substrate by
joining an electrode of the substrate to an electrode of the
semiconductor package component with a joining metal. The mounting
structure includes: a cured first reinforcing adhesive disposed
between the substrate and a surface of the semiconductor package
component facing the substrate; and a cured second reinforcing
adhesive disposed from the surface of the semiconductor package
component opposite the surface facing the substrate to the
substrate.
Advantageous Effects of Invention
[0020] With this configuration, since the reinforcing adhesive is
applied after the semiconductor package component is mounted on the
substrate, and in the heating step, the reinforcing adhesive is
sufficiently cured after the joining metal has melts and
solidifies. Thus the number of heating steps can be reduced and the
reinforcing adhesive can be readily applied in such a manner that
the reinforcing adhesive does not come into contact with the
joining metal in the process of melting and solidifying. In
addition, the quality of electrical joining between the
semiconductor package component and the substrate can be stably
maintained, and a sufficient strength of the mechanical bonding
between the semiconductor package component and the substrate can
be ensured.
[0021] With this configuration, the first reinforcing adhesive is
applied before the semiconductor package component is mounted on
the substrate; the second reinforcing adhesive is applied after the
semiconductor package component is mounted on the substrate; and,
in the heating step, the first and second reinforcing adhesives are
cured after the joining metal melts and solidifies. Accordingly,
the number of heating steps can be reduced and, even when the
application quantity of the first reinforcing adhesive is reduced
in order to prevent degradation of the joining quality due to some
of the first reinforcing adhesive mixed during the melting of the
joining metal, the cured second reinforcing adhesive ensures a
sufficient mechanical strength.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a process diagram illustrating a mounting method
according to a first embodiment of the present invention;
[0023] FIG. 2 is a perspective view illustrating a reinforcing
adhesive applied according to the first embodiment;
[0024] FIG. 3 is a cross-sectional view illustrating completion of
mounting according to the first embodiment;
[0025] FIG. 4 is a plan view of a mounting method according to a
second embodiment of the present invention;
[0026] FIG. 5 is a perspective view illustrating completion of
mounting according to the second embodiment;
[0027] FIG. 6 is a plan view of a mounting method according to a
third embodiment of the present invention;
[0028] FIG. 7 is a perspective view illustrating completion of
mounting according to the third embodiment;
[0029] FIG. 8 is a process diagram of a mounting method according
to a fourth embodiment of the present invention;
[0030] FIG. 9 is a perspective view illustrating first and second
reinforcing adhesives applied according to the fourth
embodiment;
[0031] FIG. 10 is a cross-sectional view illustrating completion of
mounting according to the fourth embodiment;
[0032] FIG. 11 is a horizontal cross-sectional view illustrating
the first and second reinforcing adhesives applied according to the
fourth embodiment;
[0033] FIG. 12 is a plan view illustrating completion of mounting
of a mounting method according to a fifth embodiment of the present
invention;
[0034] FIG. 13 is a perspective view illustrating the completion of
mounting according to the fifth embodiment;
[0035] FIG. 14 is a horizontal cross-sectional view illustrating
the completion of mounting according to the fifth embodiment;
[0036] FIG. 15 is a plan view illustrating completion of mounting
of a mounting method according to a sixth embodiment of the present
invention;
[0037] FIG. 16 is a perspective view illustrating the completion of
mounting according to the sixth embodiment;
[0038] FIG. 17 is a process diagram illustrating a conventional
mounting method;
[0039] FIG. 18 is a process diagram illustrating another
conventional mounting method;
[0040] FIG. 19 is a perspective view illustrating the method in
FIG. 18(b);
[0041] FIG. 20 is a perspective view illustrating the method in
FIG. 18(c); and
[0042] FIG. 21 is a cross-sectional view of a variation of the
third embodiment.
DESCRIPTION OF EMBODIMENTS
[0043] A semiconductor package component mounting method of the
present invention will be described below with respect to specific
embodiments.
First Embodiment
[0044] FIGS. 1 to 3 illustrate a first embodiment of the present
invention.
[0045] In FIGS. 1(a) and 1(b), a BGA semiconductor package
component 3 is mounted on a substrate 1 in such a manner that bump
electrodes 4 of the semiconductor package component 3 come into
contact with electrodes 2 on the substrate 1.
[0046] In FIG. 1(c), reinforcing adhesives 5c are applied in the
form of a stick from the periphery of an area on the substrate 1
where the semiconductor package component 3 is mounted over to the
outer surface of the semiconductor package component 3 at regular
intervals except the corner portions as illustrated in FIG. 2. This
arrangement can reduce the application quantity of the adhesive and
prevent the adhesive from unnecessarily entering between the
semiconductor package component 3 and the substrate. Since the
reinforcing adhesives 5c are applied in the form of a stick at
regular intervals except the corner portions, the semiconductor
package component 3 can be fixed in a balanced manner. The
reinforcing adhesive 5c herein is a thermoset resin. The
reinforcing adhesive 5c is applied in such a manner that the
reinforcing adhesive 5c does not contact the bump electrodes 4.
[0047] In FIG. 1(d), reflow is performed. In the reflow, the solder
of the bump electrodes 4 melts. Since the reinforcing adhesive 5c
is not cured at this point, the semiconductor package component 3
is moved to a proper position by the self-alignment effect of the
melted solder between the electrodes on the substrate 1 and the
electrodes of the semiconductor package component 3.
[0048] In FIG. 1(e), the temperature further rises to cure the
reinforcing adhesive 5c. Then the temperature is decreased to the
melting temperature of the solder or lower to solidify the solder,
thereby completing the electrical connection and mechanical bonding
of the semiconductor package component 3 and the substrate 1.
[0049] In the completed mounting structure of FIG. 3, the
reinforcing adhesive 5c can be readily prevented from contacting
the bump electrodes 4 even if the application quantities and
application positions are varied. This is because the semiconductor
package component 3 is mounted on the substrate 1 as illustrated in
FIG. 1(b) and then the reinforcing adhesive 5c is applied so that
the reinforcing adhesive 5c extends from a surface 3b of the
semiconductor package component 3 opposite a surface 3a facing the
substrate 1 to the substrate 1 as illustrated in FIG. 1(c). As
illustrated in FIG. 3, in the completed mounting structure, the
reinforcing adhesive 5c is away from the solder which is a joining
metal. Thus, good soldering quality is achieved. A portion L1 is
convex-shaped. While a portion L2 is concave-shaped, the portion L2
may be convex-shaped.
[0050] The shape of the cured reinforcing adhesive 5c is made such
that L1.gtoreq.L2, where L1 is a distance over which the
reinforcing adhesive 5c extends onto the surface 3b of the
semiconductor package component 3 opposite the surface 3a facing
the substrate 1 from an end face 3c connecting the surface 3a and
the surface 3b, and L2 is a distance over which the reinforcing
adhesive 5c extends onto the surface 3a facing the substrate 1 from
the end face 3c of the semiconductor package component 3. As a
result, a great degree of reinforcement is achieved compared with a
structure in which the reinforcing adhesive 5c is applied from the
end face 3c of the semiconductor package component 3 to the
substrate 1 as indicated by a phantom line 7 in FIG. 3 in the step
of FIG. 1(c) and then cured by reflow.
[0051] It should be noted that even when the reinforcing adhesive
5c is cured in the shape indicated by the phantom line 7 in FIG. 3,
better soldering quality and a greater degree of reinforcement are
achieved than in the conventional example illustrated in FIGS. 9 to
11.
[0052] A gap between the substrate 1 and the semiconductor package
component 3 in this case is approximately 0.2 mm. The melting point
and solidification start temperature of the solder of the bump
electrodes 4 were in the range of 217.degree. C. to 219.degree. C.
and 219.degree. C., respectively. The viscosity of the reinforcing
adhesive 5c was 60 Pas (measured with a cone and plate viscometer
at 5 rpm and 25.degree. C.) The curing start temperature of the
reinforcing adhesive 5c was 185.degree. C. and the curing peak
temperature of the reinforcing adhesive 5c was 210.degree. C.
[0053] The thixotropy of the reinforcing adhesive 5c determined
from a ratio between viscosities measured with the cone and plate
viscometer at 0.5 rpm and 5 rpm at 25.degree. C. (viscosity at 0.5
rpm/viscosity at 5 rpm) was in the range of approximately 4 to
6.
Second Embodiment
[0054] FIGS. 4 and 5 illustrate a second embodiment.
[0055] In the first embodiment, the reinforcing adhesive 5c is
applied to a portion except the corner portions 3d of the
semiconductor package component 3 and cured. In the second
embodiment, in the step of FIG. 1(c), a reinforcing adhesive 5c is
applied to portions of a semiconductor package component 3
including corner portions 3d, and distances L1 and L2 of the cured
reinforcing adhesive 5c are set such that L1.gtoreq.L2. The second
embodiment is different from the first embodiment only in the shape
of the applied reinforcing adhesive 5c. Others are the same as in
the embodiment.
[0056] In the second embodiment, better soldering quality and a
greater degree of reinforcement than in the first embodiment are
achieved.
Third Embodiment
[0057] FIGS. 6 and 7 illustrate a third embodiment.
[0058] In the second embodiment, the reinforcing adhesive 5c is
applied to the portions of the semiconductor package component 3
including the corner portions 3d of the semiconductor package
component 3 in such a manner that L1.gtoreq.L2. The third
embodiment differs from the second embodiment in that L1=0.
Specifically, the third embodiment differs from the first
embodiment only in that a reinforcing adhesive 5c is applied in
such a manner that the reinforcing adhesive 5c extends from an end
face 3c that connecting a surface 3a of a semiconductor package
component 3 facing a substrate 1 and an opposite surface 3b to the
substrate 1. Others are the same as in the first embodiment.
[0059] The reinforcing adhesive 5c is applied from the end face 3c
of the semiconductor package component 3 to cover the full height
of the end face 3c of the semiconductor package component 3 in a
position where the reinforcing adhesive 5c is applied and the
surface of the reinforcing adhesive 5c outside from the end face 3c
of the semiconductor package component 3 is concave-shaped along
the height of the end face 3c as illustrated in FIG. 21. A distance
L3 from the edge of the semiconductor package component 3 to the
perimeter of the reinforcing adhesive 5c is preferably greater than
a distance L4 from the substrate 1 to the top of the semiconductor
package component 3.
[0060] While the shape of the surface of the reinforcing adhesive
5c outside from the end face 3c is concave-shaped along the height
of the end face 3c in FIGS. 7 and 21, the completed shape of the
surface of the reinforcing adhesive 5c may be convex-shaped as
indicated by a phantom line in FIG. 21, depending on the viscosity
of the used reinforcing adhesive 5c.
[0061] According to the embodiment, better soldering quality and a
greater degree of reinforcement than in the conventional art are
achieved.
[0062] While the embodiments have been described with respect to
BGA semiconductor package components 3 by way of example, the
embodiments are also applicable to LGA (Land Grid Array)
semiconductor package components 3. In the case of the LGA
semiconductor package component 3, a paste containing a joining
metal is applied to at least one of a set of electrodes of the
semiconductor package component 3 and a set of electrodes 2 of a
substrate 1 to be joined to the set of the electrodes of the
semiconductor package component 3. Then the semiconductor package
component 3 can be mounted on the substrate 1 to implement the
present invention.
Fourth Embodiment
[0063] FIGS. 8 to 11 illustrate a fourth embodiment of the present
invention.
[0064] In FIGS. 8(a) and 8(b), a first thermoset resin 5a is
applied in the form of a dot in a position 6 on a substrate 1 where
a semiconductor package component 3 is to be mounted. FIG. 9
illustrates how the first thermoset resin 5a is applied.
[0065] In FIG. 8(c), the semiconductor package component 3 is
mounted on the substrate 1 in such a manner that bump electrodes 4
of the semiconductor package component 3 come into contact with
electrodes 2 on the substrate 1. At this point, the uncured first
thermoset resin 5a is disposed between and in contact with the
substrate 1 and the underside of the semiconductor package
component 3.
[0066] In FIG. 8(c-1), the semiconductor package component 3 is
mounted on the substrate 1 in such a manner that the bump
electrodes 4 of the BGA semiconductor package component 3 come into
contact with the electrodes 2 on the substrate 1.
[0067] In FIG. 8(c-2), a second reinforcing adhesive 5b is applied
between the periphery of the area on the substrate 1 where the
semiconductor package component 3 is mounted and the outer surface
of the semiconductor package component 3, for example, at
predetermined intervals, as illustrated in FIG. 9(b). Here, the
second reinforcing adhesive 5b is a thermoset resin.
[0068] In FIG. 8(d), reflow is performed.
[0069] FIG. 8(d) includes FIGS. 8(d-1), 8(d-2) and 8(d-3). FIGS.
8(d-2) and 8(d-3) depict cross sections as viewed from different
angles at the same point in time in the reflow to show how the
first and second reinforcing adhesives 5a and 5b have changed from
the state in FIG. 8(d-1).
[0070] In FIG. 8(d-1), the solder of the bump electrodes 4 is
melted by the reflow. Since the first and second reinforcing
adhesives 5a and 5b are uncured at this point in time, the
semiconductor package component 3 moves to a proper position by the
self-alignment effect of the melted solder between the electrodes 2
of the substrate 1 and the electrodes of the semiconductor package
component 3.
[0071] After the temperature further rises and the first and second
reinforcing adhesives 5a and 5b are cured as illustrated in FIGS.
8(d-2) and 8(d-3), the temperature is decreased to the melting
point of the solder or lower to solidify the solder, thereby
completing the electrical connection and mechanical bonding of the
semiconductor package component 3 and the substrate 1. FIG. 10 is a
vertical cross-sectional view illustrating the completion of the
mounting. FIG. 11 is a cross-sectional view taken horizontally
along a plane of the electrodes 2 of the substrate 1.
[0072] In the mounting structure completed as illustrated in FIG.
10, since the semiconductor package component 3 is mounted on the
substrate 1 and then the second reinforcing adhesive 5b is applied
from a surface 3b opposite a surface 3a of the semiconductor
package component 3 facing the substrate 1 to the substrate 1 as
illustrated in FIG. 8(c-2), strong joining between the substrate 1
and the semiconductor package component 3 can be provided by the
cured second reinforcing adhesive 5b even when the quantity of the
first reinforcing adhesive 5a is reduced to prevent the first
reinforcing adhesive 5a from contacting the solder, and strong
joining may not be provided by the first reinforcing adhesive 5a
between the substrate 1 and the package component 3. In addition,
since the second reinforcing adhesive 5b is applied after the
semiconductor package component 3 is mounted on the substrate 1,
the second reinforcing adhesive 5b is distanced from the solder
which is a joining metal, irrespective of variations of the
application quantity and application positions, as illustrated in
FIG. 10. Thus, good soldering quality is achieved.
[0073] The shape of the cured second reinforcing adhesive 5b is
made such that L1>L2, where L1 is a distance over which the
second reinforcing adhesive 5b extends onto the surface 3b of the
semiconductor package component 3 opposite the surface 3a facing
the substrate 1 from an end face 3c connecting the surface 3a and
the surface 3b, and L2 is a distance over which the second
reinforcing adhesive 5b extends onto the surface 3a facing the
substrate 1 from the end face 3c of the semiconductor package
component 3. As a result, a greater degree of reinforcement is
achieved compared with a structure in which the second reinforcing
adhesive 5b is applied from the end face 3c of the semiconductor
package component 3 to the substrate 1 as indicated by a phantom
line 7 in FIG. 10 in the step of FIG. 8(c) and then cured by
reflow.
[0074] It should be noted that even when the second reinforcing
adhesive 5b is cured in the shape represented by the phantom line 7
in FIG. 10, better soldering quality and a greater degree of
reinforcement are achieved than in the conventional example
illustrated in FIGS. 18 to 20.
[0075] A gap between the substrate 1 and the semiconductor package
component 3 at that point was approximately 0.2 mm. The melting
point and solidification start temperature of the solder of the
bump electrodes 4 were in the range of 217.degree. C. to
219.degree. C. and 219.degree. C., respectively. The viscosity of
the reinforcing adhesive 5a was 60 Pas (measured with a cone and
plate viscometer at 5 rpm and 25.degree. C.). The curing start
temperature of the reinforcing adhesive 5a was 185.degree. C. and
the curing peak temperature of the reinforcing adhesive 5a was
210.degree. C.
Fifth Embodiment
[0076] FIGS. 12 to 14 illustrate a fifth embodiment.
[0077] In the fourth embodiment, the second reinforcing adhesive 5b
is applied to portions of the semiconductor package component 3
except the corner portions 3d. In the fifth embodiment, a second
reinforcing adhesive 5b is applied to portions of a semiconductor
package component 3 including corner portions 3d of the
semiconductor package component 3 in the step of FIG. 8(c-2).
Distances L1 and L2 of the cured second reinforcing adhesive 5b are
set such that L1.gtoreq.L2. The fifth embodiment is different from
the fourth embodiment only in the shape of the applied second
reinforcing adhesive 5b. Others are the same as in the fourth
embodiment.
[0078] According to the fifth embodiment, good soldering quality
and a greater degree of reinforcement than in the fourth embodiment
are achieved as illustrated in FIG. 13. FIG. 14 is a horizontal
cross-sectional view of a first reinforcing adhesive 5a and the
second reinforcing adhesive 5b which are cured.
Sixth Embodiment
[0079] FIGS. 15 and 16 illustrate a sixth embodiment.
[0080] In the fifth embodiment, the second reinforcing adhesive 5b
is applied to the portions of the semiconductor package component 3
including the corner portions 3d of the semiconductor package
component 3 in such a manner that L1.gtoreq.L2. The sixth
embodiment differs from the fifth embodiment in that L1=0.
Specifically, the sixth embodiment is different from the fourth
embodiment only in that a second reinforcing adhesive 5b is applied
in such a manner that the second reinforcing adhesive 5b extends
from an end face 3c connecting a surface 3a of a semiconductor
package component 3 facing a substrate 1 and an opposite surface 3b
to the substrate 1. Others are the same as in the fourth
embodiment.
[0081] According to the embodiment, good soldering quality and a
greater degree of reinforcement than in the fourth embodiment are
achieved.
[0082] While the embodiments have been described with respect to
BGA semiconductor package components 3 by way of example, the
embodiments are also applicable to LGA (Land Grid Array)
semiconductor package components 3. In the case of the LGA
semiconductor package component 3, a paste containing a joining
metal is applied to at least one of a set of electrodes of the
semiconductor package component 3 and a set of electrodes 2 of a
substrate 1 to be joined to the set of the electrodes of the
semiconductor package component 3. Then the semiconductor package
component 3 can be mounted on the substrate 1 to implement the
present invention.
INDUSTRIAL APPLICABILITY
[0083] The present invention is useful for fabrication of various
electronic devices such as mobile devices that may be subjected to
drop impact.
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