JP3124983B2 - Electric circuit inspection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention relates to an electrical circuit test 査装 location by using a probe card. In this specification, a probe card is a card in which a large number of cantilever-type probe needles are fixedly arranged in accordance with the arrangement of electrodes of a circuit under test.

[0002]

2. Description of the Related Art Conventionally, as a substrate for mounting an IC chip, a printed circuit board using glass epoxy resin or a thick film circuit board formed by forming a conductor pattern on a ceramic material as seen in a hybrid IC has been mainly used. Had become. On the other hand, as a substrate with a higher mounting density, a mounting substrate in which a conductor pattern is formed on a semiconductor substrate or the like by using a thin film technology as seen in a semiconductor integrated circuit has been developed. A mounting board obtained by such a method (hereinafter referred to as a new mounting board) has a very fine pattern and a large number of wiring patterns.
With the method of inspecting a large number of spring contact terminals at once by contacting the electrodes to be inspected, such as is used in conventional inspection devices for inspecting printed circuit boards, inspection becomes dimensionally impossible. I have. Therefore, in order to inspect such a new type of mounting board, a thin probe attached to two (or four) arms is moved to a target position and a characteristic test between two points is performed. The inspection of the entire mounting board is completed by repeating the above operation twice.

[0003]

As a method for inspecting a new mounting board, the conventional inspection method in which the two-point inspection is repeated many times has a disadvantage that it takes much time.

As a method of inspecting integrated circuits formed on a wafer at once, an inspection method using a probe card is known. This probe card is
A large number of probe needles are arranged corresponding to the electrode arrangement of the integrated circuit, and the inspection of the integrated circuit is carried out efficiently by bringing the large number of probe needles into contact with the electrodes of the integrated circuit at once. . When there are a plurality of integrated circuit chips having the same specification on a wafer, each integrated circuit chip can be inspected one after another by moving the wafer with respect to the probe card. There are the following problems in using such a probe card for inspection of the above-mentioned new-type mounting board. While the electrodes of an ordinary integrated circuit chip are arranged only along the periphery of the chip, the electrodes of the new mounting board are provided not only around the board but also throughout the board. In addition, in the new mounting board, due to mounting multiple integrated circuit chips on it,
The number of electrodes is several times to several tens of times the number of electrodes of one integrated circuit chip. Therefore, it is almost impossible to cover the inspection of all the electrodes of the new mounting board with one probe card due to the difficulty in arranging a very large number of probe needles at a very high density.

An object of the present invention is to enable an electric circuit in which a very large number of electrodes are densely and densely arranged to be efficiently inspected using a probe card.

[0006]

According to a first aspect of the present invention, there is provided an electric circuit inspection apparatus comprising a plurality of probes having different probe needle arrangements.
And a test object having a circuit to be tested
Conveyed sequentially to each inspection position for the probe card
And a transfer mechanism that performs the transfer . In the present invention, the "electric circuit" includes not only a simple wiring pattern and the like but also a so-called electronic circuit including an active element such as a transistor, and the present invention can be applied to inspection of these circuits.

[0007] Delete

[0008] Delete

According to a second aspect , in the first aspect, a measuring section provided with a probe card, an alignment section for aligning the subject, and an object holding the subject and being moved between the alignment section and the measuring section. And a test station having a sample holding mechanism for positioning the subject with respect to the probe card while moving the test unit, and an electric circuit inspection apparatus is configured by combining a required number of these test stations.

[0010]

When a large number of fine electrodes to be contacted by a probe needle are densely and complicatedly arranged on a circuit to be inspected, the total number of electrode combinations to be inspected is divided into a plurality of inspection groups. I do. Then, a dedicated probe card corresponding to each inspection group is prepared, and the inspection of the circuit to be inspected is performed by using the plurality of probe cards. As a result, the inspection can be completed in a much shorter time than in the conventional method in which the two-point inspection is repeated.
ADVANTAGE OF THE INVENTION According to this invention, even if it is a circuit to be inspected which cannot be inspected collectively by one probe card because of the fine and high-density electrode arrangement, the divided inspection can be performed by combining a plurality of probe cards. Therefore, the circuit integration density is not limited due to the limit of the inspection capability, and the circuit integration density is promoted.

[0011]

FIG. 1 is a plan view showing an arrangement of probe needles of one of six probe cards used in an embodiment of an electric circuit inspection apparatus of the present invention and a subject. is there. First, the configuration of the subject will be described. The test object 10 is a mounting substrate for a multi-chip module (MCM), and is formed by forming a wiring pattern and an electrode on a silicon wafer by using a thin film technique and cutting out the wafer. A large number of peripheral electrodes 12 are arranged in the peripheral part of the subject 10, and chip-corresponding electrodes 14 composed of six groups are arranged in the central part of the subject 10. That is, six integrated circuit chips are scheduled to be mounted on the subject 10. The electrodes of each integrated circuit chip are connected to the chip corresponding electrodes 14 of each group on the subject 10 by a wire bonding method or a flip chip method. A wiring pattern 16 connects between the chip corresponding electrode 14 and the peripheral electrode 12 at the center and between the chip corresponding electrodes. FIG. 1 shows only a part of the wiring pattern 16. In an actual MCM mounting substrate, thousands of electrodes are arranged. Before mounting an integrated circuit chip on such a mounting board, an open / short test and an inspection of the capacitance between wirings are performed, and a non-defective mounting board is mounted only on a non-defective mounting board. Become.

In this embodiment, the test of the subject 10 is performed using six probe cards. FIG. 1 shows the arrangement of the probe needles of one of the probe cards. . That is, from the window 18 of the probe card,
A large number of cantilever probe needles 20 extend toward the center. These probe needles 20 are fixedly arranged corresponding to the positions of the electrodes to be contacted.

FIGS. 2A to 2F are plan views showing respective probe needle arrangements of six probe cards. Note that the arrangement of the probe needles 20 is only schematically shown for convenience of description, and is different from the actual arrangement. The same applies to the arrangement of the probe needles in FIG. The arrangement of the probe needles 20 differs among the six probe cards. That is, a large number of inspection points of the subject 10 are divided into six inspection groups, and the arrangement of the probe needles of each probe card is determined so that only the electrodes corresponding to these inspection groups can be contacted. In this case, it is important to divide the inspection group so that the inspection can be easily performed and the probe card can be easily manufactured. In this embodiment, the six probe cards are:
The shape and size of the window 18 are the same and the subject 1
The relative positions of the windows 18 with respect to 0 are all the same.

FIG. 3 is a plan view showing an arrangement of probe needles of a probe card according to another embodiment of the present invention.
In this embodiment, the position of the window 22 of the six probe cards and the relative positional relationship with the subject 10 differ depending on the probe card. That is, the area covered by each probe card is limited to a specific area of the subject 10. For example, the first probe card 24a
0 covers only the upper right area, and the other five probe cards 24b to 24f cover different areas. By using these six probe cards in order, the entire area of the subject 10 can be covered.

FIG. 4 shows a schematic structure of a probe card used in the present invention, wherein FIG.
(B) is a front view. However, only a part of the probe needle and the electrode pin is shown in the front view. The probe card 26 has a window 30 at the center of the support 28,
A large number of probe needles 32 extend from the window 30 toward the center. The probe needle 32 is a cantilever type support 28.
It is fixed to. The electrode pins 34 are arranged near the outer periphery of the support 28 and are electrically connected to the respective probe needles 32. By bringing the probe needles 32 into contact with the electrodes of the circuit under test and connecting the probe card 26 to a test head via a performance board or the like,
A test of the subject can be performed.

FIG. 5 is a plan view showing an example of the overall arrangement of the electric circuit inspection apparatus of the present invention. This inspection device has 6
Test stations 36, 38, 40, 42, 4
4 and 46, and each station is provided with six types of probe cards shown in FIG. When a subject is set in the cassette section 48, the subject is transported to the loading section 50, and further transported by the transport mechanism 52 to the first station 3.
6 is transferred to the alignment unit 54. The subject aligned here is sent to the measurement unit 56 and inspected. After the test is completed, the subject returns to the transport mechanism 52,
It is sent to the next test station 38. In this way, the subject is inspected in sequence by the different test cards at the six test stations, thereby completing the entire examination of the subject. The subject exiting from the sixth station 46 is sent to the cassette unit 60 via the unloading unit 58, and is taken out from the cassette unit 60. A series of operations from the cassette unit 48 at the entrance to the cassette unit 60 at the exit are all performed automatically.

Since each test station is unitized, the number of stations can be easily increased or decreased. For example, since the optimum number of probe cards differs depending on the circuit to be inspected, the number of stations can be increased or decreased according to the number of probe cards.

FIG. 6A is a plan view showing the structure of one test station, and FIG. 6B is a front view thereof. The subject 10 is transported to the alignment unit 54 by the transport mechanism 52. A sample stage 62 is provided in the alignment section 54.
Are on standby, and the subject 10 is placed on the sample stage 62. Above the alignment unit 54, a CCD camera 64
Are arranged, and alignment of the subject 10 is performed. In this alignment unit, the XY directions of the subject 10 are correctly matched with the XY movement directions of the sample table 62. That is, based on the information from the CCD camera 64, the sample stage 62
Is rotated in-plane (θ rotation) to correctly position the direction of the subject 10. Further, based on information from the CCD camera, the relative positional relationship of the subject 10 with respect to the sample table 62 is grasped by XY numerical values. Based on this value, how much X
By moving in the Y direction, it can be determined whether the subject 10 is positioned directly below the probe card. Sample table 62
Is vertically movable by a Z stage 66, is rotatable in a horizontal plane by a θ stage 68, and is two-dimensionally movable in a horizontal plane by an XY stage 70. The sample stage 62, the Z stage 66, the θ stage 68, and the XY stage 70 constitute a sample holding mechanism. The sample table 62 is moved from the alignment unit 54 to the measurement unit 5 with the subject 10 mounted.
Move to 6. The subject 10 on the sample table 62 is pressed against the probe needle of the probe card 26 to perform the test. The probe card 26 is supported by a probe holder 72. The configuration of each station is the same, and only the probe card 26 is different from each other.

FIG. 7 is a plan view showing another example of the overall arrangement of the electric circuit inspection apparatus of the present invention. In this example, the subject is aligned by the alignment unit 78 via the cassette unit 74 and the loading unit 76, and is inspected by the first measuring unit 80, the second measuring unit 82, and the third measuring unit 84 in that order. Further, the subject passes through the loading section 86 and the alignment section 8.
The alignment is performed again at 8, and the inspection is sequentially performed by the fourth measurement unit 90, the fifth measurement unit 92, and the sixth measurement unit 94. Thereafter, the subject returns to the cassette section 74 via the unload section 96. The six measuring units are provided with probe cards having different probe needle arrangements. The arrangement example shown in FIG. 7 shows that the parts for taking the specimen in and out of the cassette part 74 are integrated in one place, and that after the inspection by the third measurement part 84, the defective part is 5 is superior to the arrangement example of FIG.

FIG. 8A is a plan view of the configuration from the loading section 76 to the third measuring section 84 shown in FIG. 7, and FIG. 8B is a front view thereof. The subject 10 is aligned with the alignment unit 78
The sample is placed on the sample table waiting by the load arm 98. Above the alignment section 78, a CCD camera 100 is arranged. The subject aligned here is from the first measurement unit 80 to the third measurement unit 84.
Inspection is performed continuously without realignment. The sample holding mechanism is the same as that shown in FIG. 6, and the configuration of each measuring unit is also the same as that shown in FIG.

Finally, an outline of a procedure for dividing the electrode of the subject into a plurality of examination groups will be described. 9A and 9B show an arrangement structure of the probe needles, where FIG. 9A is a front view, FIG. 9B is a side view, and FIG.
Is a plan view of an electrode. In order to arrange the probe needles at high density, it is preferable to form a multilayer structure in which the bent portions of the probe needles have different heights and are arranged alternately as shown in FIG. This example has a four-layer structure. Further, it is preferable that the electrodes themselves are arranged in a plurality of rows and staggered as shown in FIG. In this example, a two-row staggered arrangement is used. Even if various measures are taken in this way, there is a limit to the arrangement density of the probe needles. For example, the minimum value of the dimension D of the bent portion of the probe needle is about 80 μm, the minimum value of the electrode pitch PW in the arrangement direction of the probe needle is about 100 μm, and the minimum value of the electrode pitch PL in the longitudinal direction of the probe needle is 150 μm
It is about.

In consideration of the above points, in order to divide the electrodes of the subject into the test groups, first, the conditions of PW being separated by 100 μm or more and PL being separated by 150 μm or more are satisfied. It is necessary to select such an electrode group. For example, if the coordinates of the electrode Pi are represented by (Xi, Yi), first, P1 (X1, Y1) and P2 (X
2, Y2), the coordinate relationship between them is PW = 100 μm.
As described above, it is determined whether the PL satisfies the condition of 150 μm or more. If satisfied, P1 and P2 belong to the same inspection group.
Next, the same determination is performed between P3 and P1 and P2. If satisfied, the same inspection group is set, and if not satisfied, P3 is divided into another inspection group. If such determination is performed for each electrode one after another, the inspection group can be divided based on the condition of the electrode pitch.

Next, a combination relationship based on the connection relationship between the electrodes is examined. For example, if an open / short inspection needs to be performed between the electrodes P1 and PA, the electrode P1
And PA must be in the same test group. Similarly, P
PB to be combined with 2 must also be included in the same test group. If P1 and P2 satisfy the electrode pitch condition but do not satisfy the electrode pitch condition between PA and PB, P1 and PA and P2 and PB need to be separated into different inspection groups. is there. By repeating such operations, a plurality of inspection groups that satisfy the conditions based on the electrode pitch and the conditions regarding the combination of inspections are completed.

Further, by judging other conditions such as checking the number of probe needles that can be arranged on one side of the probe card and checking for interference between the probe needles for the peripheral electrodes and the probe needles for the central chip corresponding electrode. Finally, the division of the inspection group is completed. These operations can be automatically performed by software incorporating a predetermined judgment formula.

The present invention is not limited to the above-described embodiment, but can be modified as follows. (1) The above-described embodiment relates to the inspection of the wiring pattern of the mounting substrate for a multi-chip module. Also applicable to That is, in the present invention, there is no particular limitation on the type of the circuit to be inspected and the contents of the inspection. The present invention is very effective for a circuit under test in which the electrodes to be contacted are very fine and numerous, and these electrodes are arranged in a complicated and high-density manner.

(2) In the above embodiment, the electrodes of the circuit to be inspected are divided into six inspection groups, and dedicated probe cards are prepared, but the number of inspection groups, that is, the number of probe cards is The number is not limited to six and can be divided into two or more arbitrary numbers.

[0027]

According to the present invention, a combination of electrodes to be inspected is divided into a plurality of inspection groups, and a plurality of exclusive probe cards having different probe needle arrangements corresponding to each inspection group are prepared. Since the inspection is performed by sequentially using these probe cards, the inspection can be completed in a much shorter time than in the conventional method in which the inspection between two points is repeated.

[Brief description of the drawings]

FIG. 1 is a plan view showing an arrangement of probe needles and a subject of a probe card used in an embodiment of an electric circuit inspection apparatus of the present invention.

FIG. 2 is a plan view showing an arrangement of probe needles of each of six probe cards.

FIG. 3 is a plan view showing an arrangement of probe needles of a probe card according to another embodiment of the present invention.

FIG. 4 is a plan view and a front view showing a schematic configuration of a probe card used in the present invention.

FIG. 5 is a plan view showing an overall arrangement example of the electric circuit inspection device of the present invention.

FIG. 6 is a plan view and a front view showing the configuration of a test station.

FIG. 7 is a plan view showing another example of the overall arrangement of the electric circuit inspection device of the present invention.

FIGS. 8A and 8B are a plan view and a front view of a configuration from a load unit 76 to a third measurement unit 84 in FIG.

9A and 9B show an arrangement structure of a probe needle, wherein FIG. 9A is a front view, FIG. 9B is a side view, and FIG. 9C is a plan view of an electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Subject 16 ... Wiring pattern 18 ... Window 20 ... Probe needle

Claims (2)

(57) [Claims] 1. A probe system comprising: a plurality of probe cards having mutually different arrangements of probe needles; and a transport mechanism for sequentially transporting a subject having a circuit to be inspected to an inspection device for each of the plurality of probe cards. Electric circuit inspection equipment. 2. A measurement unit having a probe card, an alignment unit for aligning a subject, an object holding the subject, moving the subject between the alignment unit and the measuring unit, and attaching the subject to the probe card. against unitized test station and a sample holding mechanism for positioning the electrical circuit inspection system according to claim 1, wherein the configuring the electrical circuit inspection system in combination test station only necessary number.