U.S. patent application number 09/249858 was filed with the patent office on 2002-03-07 for probe end cleaning sheet.
Invention is credited to KOZAKI, SHINICHIRO, NISHIZAKI, SHUNICHIRO, OKUBO, MASAO, SAKATA, TERUHISA.
Application Number | 20020028641 09/249858 |
Document ID | / |
Family ID | 13021424 |
Filed Date | 2002-03-07 |
United States Patent
Application |
20020028641 |
Kind Code |
A1 |
OKUBO, MASAO ; et
al. |
March 7, 2002 |
PROBE END CLEANING SHEET
Abstract
To remove foreign matter without deforming the end of a probe,
and prevent new foreign matter from adhering to the end of a probe.
A probe end cleaning sheet for removing foreign matter adhered to
the end of a probe 211, comprising a cleaning thin film 110 having
fine abrasive powder applied on the surface, an elastic sheet 120
provided in a lower layer of the cleaning thin film 110 and having
an elasticity, and a board 130 provided in a lower layer of the
elastic sheet 120, in which the cleaning thin film 110 is made of a
material which is dented when the end of the probe 211 is pressed
with a specified load but is not torn by the end of the probe 211,
and the elastic sheet 120 is made of a material which is dented in
the pressed portion by the end of the probe 211 when the end of the
probe 211 is pressed to the cleaning thin film 110 with the
specified load.
Inventors: |
OKUBO, MASAO;
(AMAGASAKI-SHI, JP) ; NISHIZAKI, SHUNICHIRO;
(KOBE-SHI, JP) ; KOZAKI, SHINICHIRO; (KIKUCHI-GUN,
JP) ; SAKATA, TERUHISA; (KIKUCHI-GUN, JP) |
Correspondence
Address: |
ARENT FOX KINTNER PLOTKIN & KAHN PLLC
1050 CONNECTICUT AVENUE, N.W., SUITE 600
WASHINGTON
DC
20036-5339
US
|
Family ID: |
13021424 |
Appl. No.: |
09/249858 |
Filed: |
February 16, 1999 |
Current U.S.
Class: |
451/49 |
Current CPC
Class: |
B24B 29/04 20130101;
B24D 11/001 20130101; B24D 3/22 20130101 |
Class at
Publication: |
451/49 |
International
Class: |
B24B 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 20, 1998 |
JP |
10-56234 |
Claims
1. A probe end cleaning sheet, being a probe end cleaning sheet for
removing foreign matter adhered to the end of a probe, comprising a
thin film for cleaning having fine abrasive powder applied on the
surface, an elastic sheet provided in a lower layer of this thin
film for cleaning and having an elasticity, and a board provided in
a lower layer of this elastic sheet, wherein said thin film for
cleaning is made of a material which is dented when the end of the
probe is pressed with a specified load but is not torn by the end
of the probe, and the elastic sheet is made of a material which is
dented in the pressed portion by the end of the probe when the end
of the probe is pressed to the thin film for cleaning with said
specified load.
2. A probe end cleaning sheet, being a probe end cleaning sheet for
removing foreign matter adhered to the end of a probe, comprising a
metal thin film for cleaning made of a metal having a hardness
nearly same as or larger than that of the material for composing
the probe, having a rough surface, an elastic sheet provided in a
lower layer of this metal thin film for cleaning and having an
elasticity, and a board provided in a lower layer of this elastic
sheet, wherein said metal thin film for cleaning is made of a
material which is dented when the end of the probe is pressed with
a specified load but is not torn by the end of the probe, and the
elastic sheet is made of a material which is dented in the pressed
portion by the end of the probe when the end of the probe is
pressed to the metal thin film for cleaning with said specified
load.
3. A probe end cleaning sheet of claim 1 or 2, wherein said
specified load ranges from several grams to scores of grams.
Description
DETAILED DESCRIPTION OF THE INVENTION
[0001] 1. Technical Field of the Invention
[0002] The invention relates to a probe end cleaning sheet for
removing foreign matter adhered to the end of a probe.
[0003] 2. Prior Art
[0004] The probe of a probe card for measuring various electric
properties of semiconductor chips formed on a semiconductor wafer
is pressed tight (overdriven) against the pad of semiconductor
chips. As a result, foreign matter such as powder of aluminum
scraped off from the pad is adhered. This foreign matter is
particularly likely to be adhered to the end of the probe when the
pad is composed of an alloy of aluminum and copper. Unless such
foreign matter is removed from the end of the probe, faulty
conduction occurs between the probe and the pad, and electric
contact is worsened, and accurate characteristics cannot be
measured. If the probe is left over for a long period, the contact
resistance tends to be higher.
[0005] To solve such problems, hitherto, the foreign matter is
removed by cleaning the end of the probe after every specified
number of times of probing.
[0006] For such cleaning, a method of using a ceramic plate, and a
method of using a probe end cleaning member for poking the end of
the probe are known.
[0007] In the former method, that is, in the method of using a
ceramic plate, a ceramic plate in an identical shape with the
semiconductor wafer is used. That is, the end of the probe is
overdriven against the ceramic plate same as in the case of
probing, and aluminum powder or other foreign matter is removed
from the end of the probe.
[0008] In the latter method, that is, in the method of using a
probe end cleaning member, the end of the probe is cleaned by
poking the end of the probe through the probe end cleaning
member.
PROBLEMS THAT THE INVENTION IS TO SOLVE However, the former method,
that is, cleaning of probe by using the ceramic plate had the
following problems.
[0009] That is, after plural times of cleaning, the end of the
probe is scraped off. The end of the probe is generally formed in a
spherical form so as to contact smoothly with the pad, but this end
is polished by the ceramic plate, and finally becomes flat. The
probe with a flat end cannot contact smoothly with the pad, and the
contact resistance changes, and the pad is worn out. The probe with
a flat end cannot be repaired by the user, or the semiconductor
device manufacturer, but can be repaired only by the probe card
maker. Therefore, the user must either discard the probe with a
flat end or request repair to the probe card maker.
[0010] In the latter method, that is, in the method of using the
probe end cleaning member, although it is possible to clean while
maintaining the shape, that is, the spherical form of the end of
the probe, the base material of the probe end cleaning member, for
example, silicone rubber or urethane rubber may be adhered to the
end of the probe. In other words, the foreign matter adhered from
the pad can be removed by cleaning, but a new foreign matter may be
adhered to the end of the probe. Besides, inside of the probe end
cleaning member, foreign matter such as aluminum powder removed
from the end of the probe is left over, and the capability of
removing the foreign matter is lowered, and therefore cleaning
cannot be done at the same position every time. Accordingly, it is
required to change the position of the probe end cleaning member on
every occasion of cleaning.
[0011] The invention is devised in the light of the above
background, and it is hence an object thereof to present a probe
end cleaning sheet capable of removing foreign matter without
deforming the end of the probe, without allowing new foreign matter
to adhere to the end of the probe.
MEANS OF SOLVING THE PROBLEMS
[0012] The probe end cleaning sheet of the invention is a probe end
cleaning sheet for removing foreign matter adhered to the end of a
probe, comprising a thin film for cleaning having fine abrasive
powder applied on the surface or a metal thin film for cleaning
made of a metal having a hardness nearly same as or larger than
that of the material for composing the probe, having a rough
surface, an elastic sheet provided in a lower layer of this thin
film for cleaning of metal thin film for cleaning and having an
elasticity, and a board provided in a lower layer of this elastic
sheet.
[0013] The thin film for cleaning or the metal thin film for
cleaning is made of a material which is dented when the end of the
probe is pressed with a specified load but is not torn by the end
of the probe, and the elastic sheet is made of a material which is
dented in the pressed portion by the end of the probe when the end
of the probe is pressed to the thin film for cleaning or the metal
thin film for cleaning with the specified load.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic explanatory diagram of cleaning of a
probe using a probe end cleaning sheet according to an embodiment
of the invention.
[0015] FIG. 2 is a drawing of the probe end cleaning sheet in the
embodiment of the invention, (A) being a schematic magnified
sectional view, (B) being a schematic plan view.
[0016] FIG. 3 is a schematic structural view for explaining
cleaning of the probe using the probe end cleaning sheet in the
embodiment of the invention.
[0017] FIG. 4 is a drawing of a probe end cleaning sheet in other
embodiment of the invention, (A) being a schematic magnified
sectional view, (B) being a schematic plan view.
[0018] FIG. 5 is a schematic structural view for explaining
cleaning of the probe using the probe end cleaning sheet in the
embodiment of the invention.
[0019] FIG. 6 is a schematic explanatory diagram showing the shape
of the end of the probe cleaned by the probe end cleaning sheet in
the embodiment of the invention.
REFERENCE NUMERALS
[0020] 100 Probe end cleaning sheet
[0021] 110 Cleaning thin film
[0022] 111 Fine abrasive powder
[0023] 120 Elastic sheet
[0024] 130 Board
[0025] 211 Probe
EMBODIMENTS
[0026] FIG. 1 is a schematic explanatory diagram of cleaning of a
probe using a probe end cleaning sheet according to an embodiment
of the invention, FIG. 2 is a drawing of the probe end cleaning
sheet in the embodiment of the invention, (A) being a schematic
magnified sectional view, (B) being a schematic plan view, FIG. 3
is a schematic structural view for explaining cleaning of the probe
using the probe end cleaning sheet in the embodiment of the
invention, FIG. 4 is a drawing of a probe end cleaning sheet in
other embodiment of the invention, (A) being a schematic magnified
sectional view, (B) being a schematic plan view, FIG. 5 is a
schematic structural view for explaining cleaning of the probe
using the probe end cleaning sheet in the embodiment of the
invention, and FIG. 6 is a schematic explanatory diagram showing
the shape of the end of the probe cleaned by the probe end cleaning
sheet in the embodiment of the invention. In the drawings,
meanwhile, the ratio of dimensions of the parts is determined for
the convenience of drafting, and is completely different from the
actual ratio of dimensions.
[0027] A probe end cleaning sheet 100 in an embodiment of the
invention is, as shown in FIG. 1, a probe end cleaning sheet for
removing foreign matter adhered to the end of a probe 211,
comprising a cleaning thin film 110 having fine abrasive powder 111
applied on the surface, an elastic sheet 120 provided in a lower
layer of this cleaning thin film 110 and having an elasticity, and
a board 130 provided in the lower layer of this elastic sheet
120.
[0028] The cleaning thin film 110 is composed by, as shown in FIG.
2, applying the fine abrasive powder 111 on the surface of a thin
film 112 with adhesive or the like.
[0029] As the fine abrasive powder 111, alumina powder, silicon
carbide powder, diamond powder or the like may be used, and the
material and size are properly determined depending on the material
and size of the probe 211.
[0030] An important point for the cleaning thin film 110 is that it
should have a sufficient rigidity so that the end may not penetrate
through the cleaning thin film 110 when the probe 211 is pressed
against with a specified load. This is also delicately related with
the characteristic of the elastic sheet 120 described below, and if
the end of the probe 211 penetrates through the cleaning thin film
110, the end of the probe 211 reaches up to the elastic sheet 120
provided in the lower layer of the cleaning thin film 110, and
therefore, as in the case of the conventional probe end cleaning
member, a new foreign matter may be adhered to the end of the probe
211.
[0031] The thickness dimension of this cleaning thin film 110 is
preferred to be, for example, 100 micrometers or less.
[0032] On the other hand, the elastic sheet 120 is made of silicone
rubber or urethane rubber having a uniform thickness dimension.
Herein, the reason of setting the elastic sheet 120 in a uniform
thickness dimension is explained below. That is, if the elastic
sheet 120 is not uniform in thickness dimension, when cleaning the
probe 211, the end of the probe 211 contacts with the probe end
cleaning sheet 100 irregularly, and in the cleaning process, an
excessive load is applied to the probe 211 coming into contact in
the first place. Therefore, the thickness dimension of the elastic
sheet 120 is preferred to be 1 millimeter or less.
[0033] The required hardness of the elastic sheet 120 is delicately
related with the characteristics of the cleaning thin film 110 as
mentioned above, and preferably the hardness should be such that it
may be dented by a load of several grams to scores of grams per one
probe 211.
[0034] That is, the elastic sheet 120 is made of material having
such a hardness as to be in the pressing portion by the end of the
probe 211 when the end of the probe 211 is pressed to the cleaning
thin film with a specified load. For example, as mentioned above,
silicone rubber or urethane rubber may be used as the elastic sheet
120.
[0035] Moreover, when the elastic sheet 120 is formed of silicone
rubber or urethane rubber, it is an advantage that it is not
necessary to glue the cleaning thin film 110 with adhesive or the
like. That is, only by putting the cleaning thin film 110 tightly
on the elastic sheet 120 made of silicone rubber or urethane
rubber, the cleaning thin film 110 is sucked and fixed to the
elastic sheet 120, and its setting is easy. If the cleaning thin
sheet 110 is glued to the elastic sheet 120 with adhesive or the
like, if the adhesive is applied unevenly, in spite of uniform
thickness dimension of the elastic sheet 120, undulations are
formed on the cleaning thin film 110 due to uneven application, and
correct cleaning is impaired, but such problem does not occur
because adhesive is not used.
[0036] The specified load for pressing the probe 211 is several
grams to scores of grams per one probe 211, and when the cleaning
thin film 110 is made of silicon carbide, the elastic sheet 120 is
silicone rubber, and the probe 211 is tungsten, it is preferably
about 3 to 10 grams.
[0037] On the other hand, the board 130 is made of, for example,
metal plate, ceramic plate, or silicone wafer. The board 130 is
required to have enough rigidity to be free from effects of
deformation of the elastic sheet 120, that is, the dent when the
end of the probe 211 is pressed.
[0038] The probe end cleaning sheet 110 thus composed by laminating
the cleaning thin film 110, elastic sheet 120, and board 130
sequentially from the upper layer side is formed in the same size
and shape as the semiconductor wafer on which the semiconductor
chip to be measured by the prober is formed. Therefore, the
thickness dimension of the probe end cleaning sheet 100 is set at
about 0.8 to 2.0 millimeters.
[0039] Herein, the following benefits are produced when the probe
end cleaning sheet 100 is in the same size and shape as the
semiconductor wafer forming the semiconductor chip thereon to be
measured.
[0040] First, the semiconductor wafer forming the semiconductor
chip to be measured is set in the prober, having a plurality held
in one cassette, and each piece is taken out of the cassette, and
electric characteristics are measured, and, by mixing probe end
cleaning sheets 100 at a specified rate, for example, one probe end
cleaning sheet 100 for every 20 semiconductor wafers, the probe 211
can be cleaned automatically. In this case, however, when the probe
end cleaning sheet 100 is taken out, different from ordinary
measurement, it is necessary to move up and down the probe 211
plural times, but it is possible to enter preliminarily the
sequence of taking out the probe end cleaning sheet 100, or to move
the probe 211 up and down only in the case of probe end cleaning
sheet 100 by detecting the probe end cleaning sheet 100 by some
means.
[0041] By thus constituted probe end cleaning sheet 100, cleaning
of the probe 211 is described below.
[0042] Preliminarily, a prober 200 using the probe 211 to be
cleaned by the probe end cleaning sheet 100 is described.
[0043] As shown in FIG. 3, the prober 200 is roughly divided into a
probe card 210, a base 220 to which the probe card 210 is attached,
and a suction table 230 for fixing the semiconductor wafer forming
the semiconductor chip to be measured.
[0044] The probe card 210 includes a plurality of probes 211
disposed corresponding to the configuration of pads of
semiconductor chips, a board 212 on which the probes 211 are
mounted, and a probe support 213 mounted on the board 212 for
supporting the probes 211. In this probe card 210, the probes 211
are mounted vertically on the board 212, and the ends of the probes
211 contact with the pads vertically, and hence it is called the
probe card of vertical operation type. In the probe 211, meanwhile,
a nearly lateral Ushaped curvature 211A is formed in order to keep
a specified contact pressure between the pads and probes 211 by
deforming when the ends are pressed against the pads. The end of
the probe 211 is formed in a spherical shape as shown in FIG. 6
(A). The probe 211 is made of tungsten.
[0045] In the board 212 of the probe card 210, a wiring pattern
212A connected to the probe 211 is formed, and the probe 211 is
connected to the tester not shown in the drawing through this
wiring pattern 212A.
[0046] The probe support 213 is intended to prevent contact with an
adjacent probe 211 when the probe 211 is pressed against the pad,
and each probe 211 is inserted into an independent penetration hole
(not shown).
[0047] The suction table 230 provided beneath the probe card 211 is
to suck and fix not only the semiconductor wafer forming the
semiconductor chip to be measured, but also the probe end cleaning
sheet 100.
[0048] By thus constituted prober 200, the end of the probe 211 is
cleaned by the probe end cleaning sheet 100 in the following
procedure. First, the probe end cleaning sheet 100 is set at a
specified position instead of the semiconductor wafer, that is, on
the suction table 230 beneath the probe card 210. For this setting,
in addition to the above method of mixing the probe end cleaning
sheets 100 at a specified rate in the semiconductor wafers, the
probe end cleaning sheets 100 may be provided in the prober 200
aside from the semiconductor wafers forming the semiconductor chips
to be measured, it may be designed to set the probe end cleaning
sheet 100 when measurement of a specified number of semiconductor
wafers is over.
[0049] When the probe end cleaning sheet 100 is set on the suction
table 230, either one or both of the probe card 210 and the suction
table 230 setting the probe end cleaning sheet 100 are moved up and
down, and the end of the probe 211 is repeatedly pressed against
the surface of the probe end cleaning sheet 100.
[0050] At this time, the load of pushing the probe 211 to the probe
end cleaning sheet 100 per probe is selected at a proper value by
the material of the cleaning thin film 110, elastic sheet 120 and
probe 211.
[0051] In this way, as the end of the probe 211 is pressed against
the probe end cleaning sheet 100, as shown in FIG. 1, without
tearing the cleaning thin film 110, the state of being wrapped in
the cleaning thin film 120 by the dent formed in the elastic sheet
120 is repeated.
[0052] Since the fine abrasive powder 111 is applied to the
cleaning thin film 110, the surface is rough, and by this rough
surface, the foreign matter adhered to the end of the probe 211 is
removed. Further, as the elastic sheet 120 presses the probe 211,
it is dented according to the end shape of the probe 211, and
therefore if the fine abrasive powder 111 is applied on the surface
of the cleaning thin film 110, unlike the conventional ceramic
plate, the end of the probe 211 is not scraped off at all.
[0053] When cleaning of the probe 211 is complete, the probe end
cleaning sheet 100 is detached from the suction table 230, and a
new semiconductor wafer to be measured next is set, and the
electric characteristics of the semiconductor chips formed on the
new semiconductor wafer are measured in succession.
[0054] In this probe end cleaning sheet 100, the cleaning thin film
110 is formed by applying fine abrasive powder 111 on the thin film
112, but instead, as shown in FIG. 4, a cleaning metal thin film
140 may be used. In this cleaning metal thin film 140, the surface
of a metal thin film 141 of, for example, tungsten is roughened by
proper means such as sand blasting or etching to for a rough
surface 142. It is more effective to treat this surface with
rhodium plating or the like.
[0055] The probe end cleaning sheet using such cleaning metal thin
film 140 is formed, same as above, by laminating an elastic sheet
120 in the lower layer of the cleaning metal thin film 140 and a
board 130 in the lower layer of the elastic sheet 120, and the
elastic sheet 120 and board 130 have same characteristics as
mentioned above.
[0056] This cleaning metal thin film 140, like the above cleaning
thin film 110, is required to have enough rigidity so that the end
of the probe 211 may not penetrate through the cleaning metal thin
film 140 when the probe 211 is pressed. If the end of the probe 211
penetrates through the cleaning metal thin film 140, the end of the
probe 211 reaches up to the elastic sheet 120 provided in the lower
layer of the cleaning metal thin film 140, and therefore, as in the
case of the conventional probe end cleaning member, a new foreign
matter may be adhered to the end of the probe 211.
[0057] The thickness dimension of the cleaning metal tin film 140
is preferred to be 5 micrometers to 50 micrometers when the
material of the cleaning metal thin film 140 is tungsten, or 20
micrometers to 100 micrometers in the case of palladium.
[0058] For example, in the case of using the probe end cleaning
sheet 100, when the probe 211 of which contact resistance is 10
ohms at the end due to deposit of foreign matter is cleaned about
10 times, by pressing the end of the probe 211 and moving the probe
211 up and down, the contact resistance becomes 0.5 ohm or less,
and there is no problem, according to the results of experiments,
in measurement of electric characteristics of semiconductor chips
formed on the semiconductor wafer.
[0059] The explanation so far relates to the probe card 210 of
vertical operation type probe card in which the probe 211 contacts
with the pad vertically, but, as shown in FIG. 5, it is similarly
applied to the so-called cantilever type probe card in which the
end of the probe 211 is folded and inclined to contact with the
pad. Moreover, as shown in FIG. 6 (B), (C), in the case of the
cantilever type probe card, the probe 211 may also have a flat
end.
EFFECTS OF THE INVENTION
[0060] The probe end cleaning sheet of the invention is a probe end
cleaning sheet for removing foreign matter adhered to the end of a
probe, which comprises a thin film for cleaning having fine
abrasive powder applied on the surface, an elastic sheet provided
in a lower layer of this thin film for cleaning and having an
elasticity, and a board provided in a lower layer of this elastic
sheet, in which the thin film for cleaning is made of a material
which is dented when the end of the probe is pressed with a
specified load but is not torn by the end of the probe, and the
elastic sheet is made of a material which is dented in the pressed
portion by the end of the probe when the end of the probe is
pressed to the thin film for cleaning with the specified load.
[0061] Therefore, when the probe is pressed against the probe end
cleaning sheet, the end of the probe is wrapped in the cleaning
thin film, and the foreign matter is removed by the fine abrasive
powder applied on the cleaning thin film. At this time, since the
cleaning thin film sheet and elastic sheet are dented according to
the shape of the end of the probe, the end of the probe is not
scraped off as experienced in the conventional ceramic plate.
Moreover, since the end of the probe does not penetrate through the
cleaning thin film, the material for composing the elastic sheet is
not adhered to the end of the probe as a new foreign matter. Still
more, the foreign matter can be removed without deforming the end
of the probe, and the probe end cleaning sheet free from deposit of
new foreign matter on the end of the probe is obtained.
[0062] Other probe end cleaning sheet of the invention is a probe
end cleaning sheet for removing foreign matter adhered to the end
of a probe, which comprises a metal thin film for cleaning made of
a metal having a hardness nearly same as or larger than that of the
material for composing the probe, having a rough surface, an
elastic sheet provided in a lower layer of this metal thin film for
cleaning and having an elasticity, and a board provided in a lower
layer of this elastic sheet, in which the metal thin film for
cleaning is made of a material which is dented when the end of the
probe is pressed with a specified load but is not torn by the end
of the probe, and the elastic sheet is made of a material which is
dented in the pressed portion by the end of the probe when the end
of the probe is pressed to the metal thin film for cleaning with
the specified load.
[0063] Also in this probe end cleaning sheet, same as in the above
probe end cleaning sheet, when the probe is pressed against the
probe end cleaning sheet, the end of the probe is wrapped in the
cleaning thin film, and the foreign matter is removed by the fine
abrasive powder applied on the cleaning thin film. At this time,
since the cleaning thin film sheet and elastic sheet are dented
according to the shape of the end of the probe, the end of the
probe is not scraped off as experienced in the conventional ceramic
plate. Moreover, since the end of the probe does not penetrate
through the cleaning thin film, the material for composing the
elastic sheet is not adhered to the end of the probe as a new
foreign matter. Still more, the foreign matter can be removed
without deforming the end of the probe, and the probe end cleaning
sheet free from deposit of new foreign matter on the end of the
probe is obtained.
[0064] The specified load ranges from several grams to scores of
grams, and a proper value may be selected depending on the material
of the cleaning thin film, cleaning metal thin film, elastic sheet
and probe.
* * * * *