More than one reissue application has been filed for the reissue of U.S. Pat. No. 5,818,249. This is a continuation of application Ser. No. 09/686,200 filed Oct. 5, 2000, now U.S. Pat. No. RE40105 issued on Feb. 26, 2008, which is a reissue application of U.S. Pat. No. 5,818,249 issued Oct. 6, 1998. This continuation application also claims benefit of priority under 35 U.S.C. § 119 to Japanese Patent Application No. 7- 249531, filed on Sep. 27, 1995.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a probe card for testing semiconductor integrated circuits and also to a method of probe-testing semiconductor integrated circuits by using the probe card.
2. Description of the Related Art
Probing test is performed on semiconductor integrated circuits for their electrical characteristics. The test is carried out after the wafer process and before the dicing process, namely after the integrated circuits have been formed in a semiconductor wafer, arranged in rows and columns. By this test it is determined whether the integrated circuits are defective or not. Any integrated circuit found defective is not subjected to an assembly step. This helps to prevent an unnecessary increase in the manufacturing cost of semiconductor devices.
The integration density of semiconductor integrated circuits (ICs) has much increased in recent years. Because of the increased integration density, the time of testing each integrated circuit, or each IC chip (hereinafter called “chip”), has increased. Until recently the probing test has been performed, chip by chip. At present a plurality of chips are tested simultaneously, in order to shorten the time of testing one chip.
FIG. 1 is a perspective view, illustrating a
conventional probe card 5 and a
semiconductor wafer 1. As
FIG. 1 shows, 84
chips 3 are arranged in rows and columns on the
semiconductor wafer 1. The
probe card 5 has one probe-needle hole
7. Protruding through the hole
7 are four groups
9a,
9b,
9c an
9d of needles to test four
chips 3a,
3b,
3c and
3d. Thus, the
probe card 5 is used to test four chips at the same time, for determining the electrical characteristics of the chips.
The integration density of semiconductor integrated circuits, particularly semiconductor memories, is still increasing. The time for testing one chip inevitably increases even if the probe card
5 (
FIG. 1) is used. In order to shorten the time, it is necessary to provide more groups of prove probe needles for each column so that the
card 5 may test more chips at the same time.
FIG. 2 is a perspective view, showing another type of a
conventional probe card 5′ and a
semiconductor wafer 1. As seen from
FIG. 2, the
probe card 5′ has eight groups
9a to
9h of needles, which protrude through a hole
7. The groups
9a to
9h of needles are provided to test eight chips
3a to
3h at the same time, whereas the four groups
9a to
9d of needles of the probe card
5 (
FIG. 1) are used to test four chips
3a to
3d simultaneously. Hence, the
probe card 5′ helps to shorten the time required for testing one chip.
When the
probe card 5′ was used to accomplish a probing test, however, more chips were likely found to be found defective than in the case where the
probe card 5 shown in
FIG. 1 was used. To determine whether this tendency is was genuine or not, the chips tested by using the
card 5′ were tested, one by one. Of the chips which were found defective when tested by means of the using
card 5′, some proved flawless. This means that the
probe card 5′ can test chips but with an insufficient accuracy.
Some reasons for the insufficient test accuracy, that are conceivable at present, will be discussed below.
The response signals output from all chips simultaneously tested are supplied at the same time to the tester via the
probe card 5′. The tester compares the levels, leading edge time and trailing edge time of the response signals with prescribed values or ranges, determining whether the chips are flawless or not.
The probe needles of the groups
9a to
9h are connected to
probe contacts 11 provided on the circumferential edge of the
probe card 5′ by wires (not shown) which are provided within the
card 5′. It is at the
probe contacts 11 that the
probe card 5′ can contact a tester. The response signal from each chip tested has its level lowered before reaching the tester, because of the resistance of the wire provided in the
card 5′. It is natural that the leading and trailing edge time of the response signal shift in accordance with the capacitance of the wire.
The more groups of probe needles provided to test more chips at a time, the greater the diameter D of the
probe card 5′. As the diameter D increases, so does the difference in length between a wire connecting a needle located at the center of the
card 5′ to the associated
contact 11 and a wire associated a needle at the edge of the
card 5′ to the associated
contact 11. As this difference increases, the differences in resistance and capacitance among the wires increase in proportion. Further, the longer the wires, the higher the probability of crosstalk among the wires.
Moreover, the larger the diameter D, the more likely the
probe card 5′ will warp. If the
card 5′ warps, the contact resistances between the chip pads on the one hand and the probe needles on the other will become different, and so will become the contact resistances between the probe needles on the one hand and the tester on the other hand. As the
probe card 5′ warps, a stress is exerted on the wires provided in the
card 5′. Each wire may have its electrical characteristics altered at that part on which an excessive stress is applied.
Any or some of the problems described above impair the accuracy of the probing test achieved by the
probe card 5′. Due to these problems, some of the chips simultaneously tested may be determined to be defective though they are actually flawless, particularly when the tester compares the levels, leading edges and trailing edges of the response signals from the chips with the prescribed values or ranges. In other words, the difference in resistance and capacitance among the wires provided in the
card 5′, the difference in pad-needle contact resistance, the difference in needle-tester contact resistance, the changes in the electrical characteristics of the wires, and the crosstalk among the wires prevent the tester from detecting the true characteristics of the chips tested at the same time.
This deterioration of probing-test accuracy is particularly prominent in the test of semiconductor memories having a large storage capacity. This is because these memories operate at so high a speed that only a little allowance is provided for the shifting of the leading and trailing edge time of each signal.
A semiconductor memory having a large storage capacity is one of the most delicate and sensitive devices. Its operation will be jeopardized if even a very small error is made. To see whether such a small error occurs or not, the memory is subjected to proving test which is performed by using a probe card under strict conditions. Therefore, a problem with the wires provided in the probe card lower the test accuracy, even if the problem is a very small one.
SUMMARY OF THE INVENTION
As indicated above, it is demanded that the time for performing probing test on semiconductor integrated circuits (ICs) be reduced as much as possible. To meet the demand it suffices to test as many IC chips as possible, at the same time. However, the more IC chips are tested simultaneously, the more chips will be determined to be defective though they are actually flawless. This would increase the manufacturing cost of the semiconductor integrated circuit.
Accordingly, the object of the present invention is to provide a probe card which can help to enhance the productivity of semiconductor integrated circuits and to reduce the manufacturing cost thereof, and also to provide a method of probe-testing semiconductor integrated circuits by using the probe card.
A probe card according to the invention is designed to test semiconductor integrated circuits formed on a semiconductor wafer and arranged in rows and columns. The probe card has groups of probe needles provided to contact semiconductor integrated circuits arranged in two columns and at least two rows. It receives a test signal from the tester and supplies the test signal simultaneously to these semiconductor integrated circuits through the groups of probe needles. It receives response signals simultaneously from the semiconductor integrated circuits through the groups of probe needles and then supplies the response signals to the tester.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention and, together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention.
FIG. 1 is a perspective view of a conventional probe card;
FIG. 2 is a perspective view of a conventional probe card of another type;
FIG. 3 is a perspective view of a probe card according to a first embodiment of the invention;
FIG. 4 is a magnified plan view of a part of the probe card, showing the probe needles;
FIG. 5A is a graph representing the results of conventional probing test;
FIG. 5B is a graph representing the results of the probing test performed by using the probe card shown in FIG. 3;
FIG. 6 is a plan view of a probe card according to a second embodiment of this invention;
FIG. 7 is an exploded view of a probe card according to a third embodiment of the invention;
FIG. 8 is a diagram explaining a probe-testing method according to a fourth embodiment of the present invention;
FIG. 9 is a diagram explaining a probe-testing method according to a fifth embodiment of this invention;
FIG. 10 is a diagram explaining a probe-testing method according to a sixth embodiment of the invention;
FIG. 11 is a diagram representing the positional relationship between the probe needles of a probe card according to a seventh embodiment of the invention, on the one hand, and the pads of an IC chip, on the other;
FIG. 12 is a diagram representing the positional relationship which the probe needles of the probe card according to a seventh embodiment may have with the pads of an IC chip;
FIG. 13 is a perspective view of a probe card according to an eighth embodiment of the invention;
FIG. 14 is a diagram showing the positional relationship between the probe needles of a probe card according to a ninth embodiment, on the one hand, and the pads of an IC chip, on the other;
FIG. 15 is a magnified plan view of a part of the probe card shown in FIG. 14, showing the probe needles;
FIG. 16 is a diagram showing the positional relationship between the probe needles of a probe card according to a tenth embodiment, on the one hand, and the path of an IC chip, on the other; and
FIG. 17 is a magnified plan view of a part of the probe card shown in FIG. 16, illustrating the probe needles.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention will now be described, with reference to the accompanying drawings. The components shown in one drawing, which are similar or identical to those shown in any other drawing, are designated at the same reference numerals and will not be described in detail.
FIG. 3 is a perspective view showing a
probe card 15 according to the first embodiment of the invention, along with a
semiconductor wafer 1.
FIG. 4 is a magnified plan view of a part of the
card 15. As
FIG. 3 illustrates,
84 IC chips 3 are provided on the
wafer 1, arranged in rows and columns.
The
probe card 15 is designed to probe-test the
chips 3. It comprises eight groups
19a to
19h of probe needles, a
substrate 20 and
probe contacts 21. The probe needles of the groups
19a to
19h can contact eight chips
3a to
3h arranged in four rows and two columns. The
card substrate 20 has a rectangular through
hole 17 having two short sides and two long sides. The first to fourth groups
19a to
19d of needles are provided on the
card substrate 20 along one long side of the
hole 17, and the fifth to
eighth groups 19e to
19h of needles are provided on the
card substrate 20 along the other long side of the
hole 17. In other words, the groups
19a to
19h of needles are arranged in two rows, each row consisting of four groups. As shown in
FIG. 4, the probe needles of the groups
19a to
19d extend downwards through the
hole 17 to contact the
external pads 31 of the IC chips
3a to
3d arranged in one column, and the probe needles of the
groups 19e to
19h extend upwards through the
hole 17 to contact the
outer pads 31 of the
IC chips 3e to
3h arranged in the next row. As shown in
FIG. 3, the
probe contacts 21 are provided on the
substrate 20, arranged along the circumferential edge of the
substrate 20. The
contacts 21 are connected to the groups
19a to
19h of needles by wires (not shown) which are provided on or in the
substrate 20.
In operation, the
probe card 15 is positioned with respect to the
semiconductor wafer 1, such that the probe needles of the groups
19a to
19h contact the
outer pads 31 of the chips
3a to
3h, respectively, as is illustrated in
FIG. 4. A test signal is supplied from a tester (not shown) to the
probe contacts 21 and hence to the groups
19a to
19h of needles through the wires. The test signal is simultaneously supplied to the eight chips
3a to
3h through the groups
19a to
19h of needles. In response to the test signal, the chips
3a to
3h output response signals, which are supplied to the
probe contacts 21 first through the groups
19a to
19h of needles and then through the wires. The response signals are ultimately supplied from the
probe contacts 21 to the tester. The tester compares the levels, leading edge time and trailing edge time of the response signals with prescribed values or ranges. Thus, the tester determines, at a time, whether eight chips
3a to
3h arranged in four rows and two columns are flawless or not.
The
probe card 15 shown in
FIG. 3 serves to test eight chips
3a to
3h at a time, as does the
conventional probe card 5′ (
FIG. 2) which has eight groups of probe needles arranged in one column. It helps to shorten the time required to test one chip, and ultimately the time required to test all chips on one semiconductor wafer.
Furthermore, the
probe card 15 has a diameter D as small as that of the conventional probe card
5 (
FIG. 1) which has four groups of probe needles arranged in one column. As a result, the difference in length between the longest and shortest wires provided on or in the
substrate 20 is similar to the
conventional card 5. It fellows follows that the differences in resistance and capacitance among the wires is proportionally similar to the
conventional card 5. Hence, the skew difference among the wires, which impairs the accuracy of probing test, disabling the tester to determine the true characteristic or ability of each chip tested is similar to the
conventional card 5. Since the
probe card 15 has a small diameter, it warps but very little, exerting but a very little stress on the wires provided on or in the
substrate 20 and scarcely altering the electrical characteristics of the wires. In addition, since the wires are short, the crosstalk among the wires is small.
In view of these advantages, the
probe card 15 can serve to enhance the productivity production of semiconductor integrated circuits and also to reduce the manufacturing cost of semiconductor integrated circuits.
FIG. 5A is a graph representing the results of conventional probing test, while
FIG. 5B is a graph representing the results of the probing test performed by using the
probe card 15. As seen from
FIG. 5A, three out of eight chips
3a to
3h were found to be flawless when tested by using the
probe card 5′ shown in FIG.
2. In
FIG. 5A, the true characteristics of the chips tested are indicated by broken lines. In view of the true characteristics of the chips, seven chips should have been found to be flawless. This means that four chips were
3a,
3f,
3g and
3h were regarded as defective, though they were flawless in fact.
When the
probe card 15 was used, testing chips
3a to
3h arranged in four rows and two columns, six of the chips were found to be flawless, as can be seen from FIG.
5B. Only one of the chips was found to be defective, though it was actually flawless, as can be understood from FIG.
5B. It should be noted that the eight chips tested by using the
probe card 15 were respectively identical in characteristics to those eight chips tested by using the
conventional probe card 5′.
Namely, some of the flawless chips which were regarded as defective when tested by using the
conventional probe card 5′ were correctly found to flawless when tested by using the
probe card 15 according to the invention. In other words, the
probe card 15 serves to test chips with high accuracy, thus saving flawless chips which would have been discarded as defective if the
conventional probe card 5′ had been used. As a result, the
probe card 15 serves to decrease the manufacturing cost of semiconductor integrated circuits.
A
probe card 15 according to the second embodiment will be described, with reference to
FIG. 6 which is a plan view. The second embodiment is characterized in that groups of wires are arranged on or in the
substrate 20 such that all wires are as short as possible.
As shown in
FIG. 6, the
probe card 15 has a substrate. The substrate has a rectangular through
hole 17 extending along a
diameter 30 of the
substrate 30. The substrate has a
right half 33R and a
left half 33L on the right and left sides of the
diameter 30, respectively. Provided in the
right half 33R are four wiring regions
35a to
35d. Provided in the
left half 33L are four
wiring regions 35e to
35h. In the wiring region
35a, a group
37a of wires is provided, connecting the probe contacts of a group
21a to the probe needles of the group
19a (not shown) which are to contact the pads of a chip
3a. Similarly, in the
wiring region 35b, a
group 37b of wires is provided, connecting the probe contacts of a
group 21b to the probe needles of the
group 19b (not shown) which are to contact the pads of a
chip 3b. In the other wiring regions
35c to
35h, groups
37c to
37h of wires are provided, respectively, each connecting a probe pad to a probe needle. For example, the wires of the
group 37h provided in the
wiring region 35h connect the probe pads of the
group 21h to the probe needles of the
group 19h which are to contact the pads of a
chip 3h.
Thus the four groups
19a to
19d of probe needles to contact the chips
3a to
3d, groups
21a to
21d of probe contacts, and groups
37a to
37d of wires are arranged in the
right half 33R of the substrate. The remaining four
groups 19e to
19h of probe needles to contact the
chips 3e to
3h,
groups 21e to
21h of probe contacts, and
groups 37e to
37h of wires are arranged in the right
left half 33L of the substrate.
Arranged as shown in
FIG. 6, the wires of the groups
37a to
37h are shorter than otherwise, and the difference in length between the longest and shortest wires provided is relatively small. Hence, the differences in resistance and capacitance among the wires is proportionally small. In addition, since the wires are short, the crosstalk among the wires is small. The
probe card 15 according to the second embodiment can therefore help accomplish high-accuracy probing test, in which eight chips are tested at the same time.
Another
probe card 15 according to the third embodiment of this invention will be described, with reference to
FIG. 7 which is an exploded view. The third embodiment is similar to the first embodiment. It is characterized in that the
substrate 20 is designed so as to reduce the crosstalk among the wires.
As illustrated in
FIG. 7, the
substrate 20 is composed of seven layers
20-
1 to
20-
7. Probe
contacts 21 are mounted on the first layer
20-
1. This
probe card 15 is designed for use in testing semiconductor memories and has six types of
wires 27, which are: address signal wires; data signal wires; ground (VSS) wires; control wires for supplying control signals such as row-address strobe signals and column-address strobe signals; power-supply wires; and other wires for a monitor or the like. The address signal wires are provided on the second layer
20-
2, the data signal wires on the third layer
20-
3, the ground wires on the fourth layer
20-
4, the control wires on the fifth layer
20-
5, the power-supply wires on the sixth layer
20-
6, and the other wires on the seventh layer
20-
7. The wires
37 provided on the second to seventh layers
20-
2 to
20-
7 extend through
holes 39 made in these layers
20-
2 to
20-
7 and are connected to the
probe contacts 21 which are provided on the first layer
20-
1.
Since the wires
37 of each type are provided on one layer, not together with the wires of any other type, the crosstalk among the wires
37 is far less than in the case all wires are arranged densely on one and the same layer. The
probe card 15 according to the third embodiment can, therefore, help to achieve high-accuracy probing test. It has eight groups of probe needles and can serve to test eight chips at the same time.
The third embodiment can be used in combination with the probe card according to the second embodiment.
Methods of probe-testing semiconductor integrated circuits by using the probe card according to the invention will be described as the fourth, fifth and sixth embodiments.
FIG. 8 is a diagram explaining the probe-testing method according to the fourth embodiment. This method can test more chips at the same time than is possible by using the
probe card 15 according to the first embodiment.
As shown in
FIG. 8, four test stations
43-
1 to
43-
4 are provided for one
tester 41. Each test station is equipped with one probe card. More precisely, the test stations
43-
1 to
43-
4 have probe cards
15-
1 to
15-
4, respectively. Four
semiconductor wafers 1—
1 to
1-
4 are located at the test stations
43-
1 to
43-
4, respectively. Using the probe cards
15-
1 to
15-
4, the
tester 41 tests four
wafers 1—
1 to
1-
4 simultaneously.
With this method, the more test stations are installed, the more chips can be tested at the same time with high accuracy. Namely, L×M chips can be tested at a time, where L is the number of chips that can be simultaneously tested by using one probe card, and M is the number of test stations installed.
In the instance shown in
FIG. 8, L=8 and M=4. Hence, the
tester 41 can test 32 chips at a time. The probe cards
15-
1 to
15-
4 may be those of the first embodiment, the second embodiment, the third embodiment or a combination of the second and third embodiments. Since the
probe card 15 of any embodiment serves to test chips with high accuracy, the
tester 41 can test as many as 32 chips simultaneously with sufficiently high accuracy.
FIG. 9 is a diagram explaining the probe-testing method which is the fifth embodiment of this invention. The fifth embodiment requires but little cost per chip, and is better in cost performance than the method according to the fourth embodiment.
As illustrated in
FIG. 9, the method uses one
tester 41 and one
test station 43. The
test station 43 is equipped with two probe cards
15-
1 and
15-
2. The probe cards
15-
1 and
15-
2 are used at the same time to test chips provided on one
semiconductor substrate 1. In this method, the
tester 41 can test L×N chips simultaneously, where N is the number of probe cards provided at the test station
42 and L is the number of chips that can be simultaneously tested by using one probe card. Hence, one test station can test more chips at the same time than is possible with the fourth embodiment, with the same accuracy as is possible with the fourth embodiment. In the case shown in
FIG. 9, wherein L=8 and N=2, the test station
42 can test 16 chips at a time, whereas each test station can test only 8 chips at a time in the fourth embodiment (FIG.
8). Furthermore, the accuracy of probing test remains high, because both probe cards
15-
1 and
15-
2 attached to the
station 43.
Still further, the number of chips tested simultaneously at one test station increases since two or
more probe cards 15 are attached to one test station. Therefore, the facility cost for testing one chip is low. Having only one test station, the prober probing system shown in
FIG. 9 occupies a smaller floor area than the prober probing system shown in
FIG. 8 which needs two test stations to test the same number of chips at the same time. The smaller the floor area required, the lower the air-conditioning cost required, or the hither higher the air purity in the probing room. In view of this, the probe-testing method according to the fifth embodiment helps to decrease the possibility that chips are contaminated with harmful substance such as sodium and the possibility that the wires of each chip are short-circuited by electrically conductive particles such as silicon dust.
As may be understood from FIG. 9, the method according to the fifth embodiment is advantageous when used to test a large semiconductor wafer which has an increased number of chips.
FIG. 10 is a diagram explaining a probe-testing method according to the sixth embodiment of the present invention. As may be seen from FIG. 10, the sixth embodiment is a combination of the methods according to the fourth and fifth embodiments.
In the sixth embodiment, two test stations
43-
1 and
43-
2 are provided for one
tester 41, and two probe cards are attached to each test station. To be more specific, probe cards
15-
1 and
15-
2 are attached to the first test station
43-
1, and probe cards
15-
3 and
15-
4 to the second test station
43-
2. Two
semiconductor wafers 1—
1 and
1-
2 are simultaneously tested at the test stations
43-
1 and
43-
2, respectively, by using the four probe cards
15-
1 to
15-
4.
The probe-testing method according to the sixth embodiment can test L×M×N chips at the same time, where L is the number of chips one probe card can test at a time, M is the number of test station provided, and N is the number of probe cards attached to one test station. The sixth embodiment can serve to test many chips simultaneously with high accuracy as does the fourth embodiment, and can achieve good cost performance as does the fifth embodiment.
A semiconductor IC chips chip which can be easily tested by using a probe card which is according to the seventh embodiment of the invention will now be described.
Like the first to third embodiments, this probe card is designed to test IC chips arranged in two columns and at least two rows, at the same time, to determine whether the chips are flawless or defective. The probe card comprises a substrate having a rectangular through hole. It is desirable that some of the probe needles be arranged along one long side of the hole to contact the pads of the chips provided on a semiconductor wafer and forming one column and that the other probe needles be arranged along the other long side of the hole to contact the pads of chips provided on the wafer and forming a next column. If the probe needles are thus arranged, the wires provided on or in the substrate can be made shortest as has been explained in conjunction with the second embodiment.
A semiconductor IC chip should have pads arranged in a column to be tested by using the a probe card according to the invention, which has groups of probe needles arranged in the specific manner described above.
FIG. 11 is a diagram representing the positional relationship between the probe needles of the probe card, on the one hand, and the pads of the
IC chip 3, on the other. As shown in
FIG. 11, the
chip 3 is rectangular and has a column of
pads 31 arranged along the longitudinal axis. This type of a chip is known as “center-pad type” and is used in, for example, semiconductor memories of large storage capacity.
It is easy to bring the probe needles of one
group 19 provided on the probe card into contact with the
pads 31 because the
pads 31 are arranged in a column. Even if identical chips on the semiconductor wafer are arranged in two columns as shown in
FIG. 4, there will be formed only two columns of
pads 31 which are to contact the probe needles of one
group 19 provided on the probe card. Arranged in two columns, the
pads 31 can easily contact the needles of the
group 19 provided on the probe card, some of which are arranged along one long side of the rectangular hole of the substrate and the others of which are arranged along the other long side of the rectangular hole.
Alternatively, the
pads 31 may be arranged in staggered fashion as is illustrated in FIG.
12.
A
probe card 15 according to the eighth embodiment of this invention will be described, with reference to
FIG. 13 which is a perspective view.
As shown in
FIG. 13, this
probe card 15 serves to test 16 chips simultaneously, which are arranged in eight rows and two columns, whereas the first embodiment (
FIG. 3) serves to test eight chips at the same time, which are arranged in four rows and two columns.
Designed to test chips arranged in eight rows, the
probe card 15 inevitably have has a larger diameter D than the first embodiment (FIG.
3). Hence, it may have the same problems as does the
conventional probe card 5′ (FIG.
2). Nevertheless, the eighth embodiment will be practically useful since the probe card technology is well expected to advance to simultaneously test 16 chips arranged in eight rows and two columns, with accuracy as high as in the case eight chips arranged in four rows and two columns are tested at the same time. Needless to say, the eighth embodiment has a smaller diameter than a conventional probe card which is designed to test 16 chips arranged in a single column. The eighth embodiment (
FIG. 13) can therefore help not only to increase the productivity production of semiconductor integrated circuits, but also to reduce the manufacturing cost of semiconductor integrated circuits.
As can be understood from the eighth embodiment, the present invention is not limited to probe cards which are designed to test eight chips arranged in four rows and two columns. Rather, the invention can provide probe cards which serve to test more chips at a time, arranged in more rows and two columns.
A probe card according to the ninth embodiment of the present invention will be described, with reference to FIGS. 14 and 15. The ninth embodiment is designed to test semiconductor memories each having a large storage capacity and, hence, a relatively large number of pads.
As shown in
FIG. 14, a semiconductor memory to be tested has 24 pads arranged in eight rows and three columns. The probe card has
group 19 of probe needles, each group consisting of 24 needles which are arranged in eight rows and three columns.
FIG. 15 is a plan view showing how the probe needles of groups
19a to
19h are positioned with respect to the
pads 31 of semiconductor memories
3a to
3h. (Shown in
FIG. 15 are
only groups 19a,
19b,
19g and
19h and
only memories 3a,
3b,
3g and
3h.) As the probe card technology advances as expected, each
group 19 may consists consist of more probe needles arranged in m rows and n column, where m>8 and n>3, whereby the probe card can test semiconductor integrated circuits each having more pads.
A probe card according to the tenth embodiment of the invention will be described, with reference to
FIGS. 16 and 17. As seen from
FIGS. 16 and 17, this probe card is designed to test semiconductor integrated circuits each having
many pads 31 which are arranged in m rows and n columns in staggered fashion.
In the
probe cards 15 according to the invention, which are shown in
FIGS. 3,
6,
7 and
13, the
probe contacts 21 are arranged in a circle, along the circumference of the
substrate 20. The probe card may need to have so
many probe contacts 21 that it is no longer possible to arrange the
contacts 21 in one circle. If so, the
probe contacts 21 may well be arranged in two or more concentric circles.
As has been described, the present invention can provide a probe card which can help to enhance the productivity of semiconductor integrated circuits and to reduce the manufacturing cost thereof, and can also provide a method of probe-testing semiconductor integrated circuits by using the probe card.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative devices, and illustrated examples shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.