JPH0648706B2 - Wiring pattern inspection method and inspection device therefor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for inspecting a wiring pattern of a wiring chip (or a wiring substrate) or an LSI chip adopting control collapse bonding (hereinafter abbreviated as CCB) and its inspection. It relates to the device.

[Background technology]

Currently, multi-chip modules (generally called memory modules, etc.) are being developed,
In this multi-chip module, a logic chip or a memory LSI is mounted on a wiring chip (or a wiring board) to form one L-chip.
It is SI.

This wiring chip includes a wire bonding pad 2 and a CCB arranged on the substrate of the wiring chip 1 as shown in FIG.
Wiring 4 is provided between the pads 3 or between the CCB pads 3, and a memory LSI 5 and a logic LSI 6 are attached by using the solder bumps 3'as indicated by the one-dot chain line to enable complicated systematic mounting. It is a thing.

By the way, first of all, to check whether the wiring 4 is open or short-circuited, the memory or logic LSI is checked.
It is necessary to do it before attaching 5 and 6. Therefore, after the wiring 4 is provided as described above, the two adjacent CCB pads 3
All are short-circuited by the solder bridge 7 as shown in FIG. 6, and then the probe of the prober is applied to the bonding pad 2 to connect the wiring 4 from the bonding pad 2 side.
It is checked by conducting an open / short inspection. At the time of actual mounting, solder reflow treatment (heat treatment) is performed on the solder bridge 7 of FIG.
As shown in the figure, all the solder bridges 7 formed between the adjacent CCB pads 3 are cut to be in an open state. Then, the LSIs 5 and 6 are placed on the formed solder bumps and systematic mounting is performed.

Further, the wiring chips 1 are selected by the first test result when all the adjacent CCB pads 3 are short-circuited by the above-mentioned solder bridge and the first test result when all the solder bridges are opened by the solder reflow process. The quality of the wiring chip 1 is determined from the test result of No. 2. Therefore, the discrimination process is a process such as the first test-heat treatment-second test, and the discrimination process is long and the discrimination takes time. Further, under the present condition that heat treatment is performed on a wafer-by-wafer basis corresponding to one wiring chip 1, the test results when all the CCB pads 3 are short-circuited by the solder bridge 7, and when all the CCB pads 3 are opened. The quality of the wiring chip 1 is judged from the test result of 1., but the test path of the wiring pattern cannot be activated because there are only two test conditions. Therefore, it may not be possible to detect wiring defects as follows. That is, when the state before heat treatment is as shown in FIG. 8, the CCB pad B portion and CC
The B pad C portion is short-circuited, and the CCB pad D portion and E portion are short-circuited, so that the bonding pad A and the bonding pad F are in a short state (see FIG. 9A). Therefore, at this time, the probe inspection is performed on the bonding pads A and G, and G and F, and whether or not there is a short circuit between the wiring 4a and the wiring 4b connected to the bonding pad G, and the probe inspection on the bonding pads A, H, H, and F. Then, the presence or absence of a short circuit between the wiring 4c and the wiring 4d connected to the bonding pad H can be detected. However, when heat treatment is performed, CCB pads B, C
During this period, the CCB pads D and E are in an open state, respectively, and it is not possible to detect a short circuit between the wirings 4b and 4e from the test result in this open state and the test result before the heat treatment. As described above, the defect detection of the wiring may be impossible in some cases, and the defect detection rate is low.

In addition, as an example in which the wafer prober technology is described in detail, an electronic material issued by the Industrial Research Group, November 1981, separate volume,
Published November 10, 1981, P. 221-225.

[Object of the Invention]

It is an object of the present invention to increase the test conditions to activate the test path of the wiring pattern, which can improve the defect detection rate of the wiring and improve the reliability. It is an object of the present invention to provide a wiring pattern inspecting method and an inspecting apparatus for the wiring pattern, in which a process for selecting the quality of a substrate on which is formed can be short-circuited to reduce the product cost.

The above and other objects and novel characteristics of the present invention are
It will be apparent from the description of the present specification and the accompanying drawings.

[Outline of Invention]

The outline of a typical one of the inventions disclosed in the present application will be briefly described as follows.

That is, when inspecting a wiring pattern formed by wiring between terminals of CCB pads and bonding pads arranged on the substrate of a wiring chip, solder between the CCB pads necessary for checking is used as a conductive member for inspection. Pre-connect with a bridge, and at the time of inspection, each solder bridge is sequentially irradiated with a laser beam by a laser beam irradiation device, and the irradiation energy is used to cut the solder bridges at the relevant points in order, A prober is used to check the presence or absence of short circuits between bonding pads at certain points, and the presence or absence of short circuits in the required parts of the tester wiring pattern can be checked based on the detection signal. The test conditions can be increased depending on the cutting position, order, and range, and the wiring pattern Improvement of failure inspection of the interconnections achieving activation of over down the test path, which leads to an improvement of the signal such properties. Furthermore, since the solder reflow process can be performed at the same time when the probe inspection is performed, the process for selecting the quality of the wiring chips can be shortened, and the selection time and the product cost can be shortened. Is.

〔Example〕

FIG. 1 shows an embodiment of a wiring pattern inspection apparatus according to the present invention, and FIGS. 2 and 3 show an embodiment of a wiring pattern inspection method according to the present invention. In the following, the case where the present invention is applied to the inspection of wiring chips will be taken as an example.
This will be described with reference to FIGS.

First, the wiring chip 11 to which the present invention is applied has the same structure as that described with reference to FIG. That is, the bonding pad 2 is arranged around the substrate, and the CCB pad 3 is arranged inside the bonding pad 2. Between the bonding pad 2 and the CCB pad 3,
Wiring is formed between the CCB pads 3 and the CCB pads 3 to form a wiring pattern. A memory LSI 5 and a logic LSI 6 are mounted on these CCB pads 3.

By the way, in order to select (determine) the quality of the wiring chip 11, it is necessary to check whether the wiring pattern is open / short, that is, whether the wiring of the wiring pattern is open / short. Therefore, the wiring chip 11
When inspecting the wiring pattern formed above, adjacent CCs of each CCB pad 3 that are necessary for checking in advance.
A wiring pattern for short-circuiting (short-circuiting) the B pads 3 with solder bridges 7 as conductive members for inspection, and checking the presence / absence of open / short-circuiting of the wirings 4 while sequentially partially cutting the solder bridges 7. The inspection device is configured as follows.

That is, 12 is a stage, and this stage 12 is driven by a drive circuit 13, and this drive circuit is controlled by the control unit 15 of the tester 14. The wiring chip 11 is placed on the stage 12. A vacuum suction method may be used for mounting the wiring chip 11. Reference numeral 16 is a prober having a rectangular (cross-sectional shape) through hole 16a in the center thereof. The prober 16 has a large number of probe needles 16 as shown in FIGS.
b, and each probe needle 16b is positioned at a predetermined interval so that each of these probe needles 16b is correspondingly arranged on each bonding pad 2. A laser beam irradiation device 17 as an energy irradiation device is provided on the through hole 16a at the center of the prober 16.
The laser beam irradiation device 17 may be configured integrally with the prober 16 or may be separately provided.

By the way, in the wiring chip 11, the position of the CCB pad 3 is determined by the layout with respect to the position of the bonding pad 2. Therefore, the position information of the CCB pad 3 of the wiring chip 11 is input to the tester 14 in advance.
Further, at the time of inspection, the laser beam irradiation device 17, the prober 16 and the wiring chip 11 are aligned in advance. That is, the bonding pad and the probe 16b are aligned, the laser beam irradiation position and the solder bridge are aligned, and the like. Here, description will be given below assuming that the alignment of the wiring chip 11 is completed.

The control unit 15 of the tester 14 follows the position information of the CCB pad 3 to the laser beam irradiation device 17, and based on the position command signal for instructing the position of the solder bridge 7 at the position to be cut, the solder bridge between the CCB pads 3 at the corresponding positions. As shown in FIG. 1 and FIG. 2, the laser beam 18 as an energy ray is irradiated to 7 and the solder bridge 7 is cut (fused) by the irradiation energy. The solder reflow process is performed with the irradiation energy at this time to form the solder bumps 3 '. In this case, the laser beam irradiation device 17 is configured to be scan-controlled based on the position command signal based on the position information of the CCB pad 3 from the controller 15. In FIGS. 2 and 3, the laser beam irradiation device 17 and the prober 16 are integrated, and the device itself is indicated by an arrow 19 in FIG.
It is possible to scan in each direction of .about.22, so that the laser beam spot 23 can be scanned in the directions of arrows 19 to 22. Therefore, the laser beam irradiating device 17 scans the laser beam spot 23, and the solder bridges 7 between the CCB pads 3 at the corresponding positions are sequentially fused based on the position command signal. On the other hand, the prober 16 is supplied with a detection command signal corresponding to the position command signal from the controller 15, and the prober 16 of the corresponding position is arranged on the prober 16 based on the detection command signal. The detection signal (current signal or voltage signal) from the bonding pad 2 is sent to the measuring unit 24 on the tester 14 side. The measuring unit 24 measures this detection signal and compares it with a predetermined threshold value in the comparison unit 25, and if it is above a predetermined threshold value, it is converted into a digital signal such as "1", and if it is smaller than that, it is converted into a digital signal. It is converted and input to the memory unit 26. In this memory unit 26, the presence or absence of a short circuit of the corresponding wiring (“1”, “0”) corresponding to the detection signal between the CCB pads 3 which are sequentially fused in accordance with the scanning of the laser beam.
Will be remembered. On the other hand, in the memory unit 27, the presence / absence of a short circuit in the wiring of the wiring pattern as designed in advance (open / open
Short information) (“1”, “0”) has been input.
Therefore, by comparing the information from both the memory units 26 and 27 in the comparison unit 28, a wiring defect of the wiring pattern is detected when they do not match, and the display unit 29 displays the location of the wiring defect (short circuit) or the wiring chip 11. The result of the pass / fail judgment is displayed. Further, the wiring chip 1 according to the comparison in the comparison unit 28
The judgment signal of "1", the judgment signal of defective wiring, etc. can be taken out to the outside as appropriate.

The tester 14 includes a control unit 15, a measuring unit 24, and comparisons 25 and 2.
8, a memory unit 26, 27, a display unit 29, and the like, and this tester 14 can check whether or not there is a short circuit in a wiring of a wiring pattern of the wiring chip 11 and thus determine whether the wiring chip 11 is good or bad. ) Will be done.

When the wiring pattern is inspected as described above, in the case where the wiring pattern on the wiring chip 11 has the structure shown in FIG. 8, the CCB pad B portion and the C portion and the CCB pad D portion and the E portion are separated. Is short-circuited by the solder bridge 7, the bonding pads A and F are in a short-circuited state, and the probe inspection of the bonding pads A and G or the bonding pads F and G leads to the bonding pad G (connection to the bonding pad G). The short-circuit with the connected wiring 4a) can be checked (detected), and the bonding pad H (the wiring 4 connected to the bonding pad H can be detected from the probe inspection of the bonding pads A and H or the bonding pads F and H).
The short circuit with e) can be checked (detected). Although this is the same as the current situation, when the CCB pads B and C are opened by irradiating the solder bridge 7 of the memory mounting portion [I] with the laser beam, a short circuit between the bonding pads A and F occurs. The presence or absence (defective) of the short circuit between the wirings 4b and 4e, which cannot be checked (detected) at present, can be checked (detected) by inspecting the existence of the bonding pads A and F by probe inspection (FIG. 9). (See (b)). Then, by irradiating the logic mounting section [II] with a laser beam, CC
The B pad D portion and E portion are in the open state, which is the same state as when the above-described heat treatment (reflow treatment) is completed.

As described above, in the present invention, the solder bridges 7 are not inspected after all the solder bridges 7 are opened.
By sequentially opening the CCB pads 3 in which the wiring is formed, it is possible to detect the presence or absence of a short circuit between the wirings, which cannot be detected at present.

Further, by controlling the scanning of the laser beam spot by the laser beam irradiation device 17 from the control unit 15 from the tester 14 by the position command signal, the necessary solder bridges 7 can be cut (blown) sequentially. The test conditions can be increased depending on the position, the order, and the range of cutting the solder bridge 7 by the irradiation of light, the test path of the wiring pattern can be activated, and the reliability of the obtained test result can be improved. .

Furthermore, since the solder reflow process can be performed simultaneously with the cutting of the solder bridge 7 during the test execution, that is, when the probe inspection is performed, when the cutting of the solder bridge 7 is completed, the solder reflow process is also completed. There is no need to provide a heat treatment step. Therefore, the process for selecting (determining) the quality of the wiring chip 11 is shortened, and the determination time and the product cost can be shortened.

〔effect〕

(1) By irradiating energy rays, the test conditions of the wiring pattern can be increased depending on the position, order, and range of cutting the conductive member for inspection, which is pre-connected between the terminals arranged on the substrate for checking. It is possible to activate the test path of the wiring pattern, improve the defect detection rate of the wiring, and thus the defect detection rate of the substrate on which the wiring pattern is formed, and inspect the wiring pattern (inspection of the quality of the substrate). Can increase the reliability of.

(2) Since a reflow process (heat treatment) can be performed on the conductive member at the same time as cutting the conductive member for inspection (for example, the solder bridge 7 and Al described above) at the time of mounting the probe inspection, the terminals required for checking on the board. When the cutting of the conductive members connected between them is completed,
The reflow process for the conductive member is also completed, which eliminates the need for a heat treatment process. Therefore, it is possible to reduce the quality of the substrate and reduce the product cost.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention. Nor. For example, although the solder bridge 7 is used as a conductive member for inspection in which the CCB pads 3 are preliminarily connected to each other, for a wiring test using a conductive member (for example, Al or polycrystalline silicon) as shown in FIG. The pattern 30 may be used. In FIG. 4, for example, the bonding pad I and the CCB pad J
In order to check the open / short of the wiring pattern between the CCB pad K and the bonding pad L,
When the wiring pattern is formed on the substrate, the wiring test pattern 30 is added in advance in place of the solder bridge 7, and the pattern 30 is directly cut by a laser beam at the time of the test (the cut portion is marked with an X mark). However, even when the pattern 30 is used, it is possible to obtain the same effects as those of the present embodiment as described above.

Further, as the energy beam irradiation device, the laser beam irradiation device 17 using a laser beam as the energy beam is used, but X-rays, ion beams, electron beams, etc. can be considered as the energy beams, and these energy levels can be used. An energy ray irradiation device using rays may be used.

[Field of application]

In the above description, the case where the invention made by the present inventor is mainly applied to the inspection of the wiring chip which is the background field of application has been described, but the present invention is not limited to this. For example, a general CCB adopted LGI chip is used. It can be applied to inspection.

[Brief description of drawings]

FIG. 1 is a simplified diagram showing an embodiment of a wiring pattern inspection device according to the present invention, FIGS. 2 and 3 are simplified explanatory diagrams showing an embodiment of a wiring pattern inspection method according to the present invention, and FIG. A simplified explanatory view showing another embodiment of the wiring pattern inspection method according to the present invention, FIG. 5 is an explanatory view for explaining the systematic mounting of the wiring chip, and FIGS. 6 (a) and 6 (b) are CCBs, respectively. A sectional view and a plan view showing a state in which a solder bridge is formed between pads, and FIGS. 7A and 7B are sectional views showing a state after heat treatment is applied to the solder bridge in FIG. 6 respectively. FIG. 9 is a plan view, FIG. 8 is an explanatory view showing an example of a conventional wiring pattern inspection method, and FIGS. 9 (a) to 9 (c) are main-portion cross-sectional views showing electrical connections in FIG. 2 ... Bonding pad, 3 ... CCB pad, 3 '
... Solder bumps, 4 (4a-4e) ... Wiring, 7 ...
Solder bridge, 11 ... Wiring chip, 12 ... Stage, 13 ... Drive circuit, 14 ... Tester, 15 ... Control part, 16 ... Prober, 16b ... Probe needle, 17 ...
… Laser beam irradiation device, 18 …… Laser beam, 23 ……
Laser light spot, 24 ... Measuring unit, 25, 28 ... Comparison unit, 26, 27 ... Memory unit, 29 ... Display unit, 30
...... Wiring test pattern.

Claims (6)

[Claims] 1. A method for inspecting a wiring pattern formed by wiring between terminals arranged on a substrate, wherein terminals required for checking among the terminals on the substrate are preliminarily connected by a conductive member for inspection. In addition, during inspection, the conductive member between the terminals is sequentially irradiated with energy rays, and while the conductive member at the relevant location necessary for checking the irradiation energy is sequentially cut off, an open short circuit between the terminals at the predetermined location is performed. The method for inspecting a wiring pattern is characterized in that it is possible to check whether or not there is an open circuit in a wiring at a required portion of the wiring pattern by inspecting the presence or absence of the wiring pattern. 2. The wiring pattern inspection method according to claim 1, wherein a laser beam, an ion beam, an X-ray, or the like is used as the energy beam. 3. When inspecting a wiring pattern formed by wiring between terminals arranged on a substrate, each of the terminals required for checking is short-circuited by a conductive member for inspection in advance. In addition, in the wiring pattern inspection device for checking the presence or absence of open short circuit of the wiring while sequentially cutting these conductive members, there is a probe arranged on each terminal necessary for the inspection on the board, and the detection command signal Based on the prober that sends out the detection signal from the terminal where the probe at the relevant location is arranged, and the conductive member between the terminals at the relevant location based on the position command signal, the energy beam is irradiated, and the conductive energy is applied to the conductive member. And an energy beam irradiating device for cutting the wire, and the position command signal for instructing the position of the conductive member to be cut to the energy beam irradiating device. At least a tester for sending a detection command signal corresponding to the position command signal to the prober, and further for checking the presence or absence of an open short circuit in a required portion of the wiring pattern based on the detection signal from the prober. Wiring pattern inspection device characterized by. 4. The energy irradiating device is configured to scan-control the irradiation position of the energy beam based on a position command signal from the tester.
The wiring pattern inspection device according to the item. 5. The probe according to claim 3, wherein the prober and the energy ray irradiation device are integrally formed.
The wiring pattern inspection device according to the item. 6. The wiring pattern inspection device according to claim 3, wherein a laser beam, an ion beam, or an X-ray is used as an energy beam in the energy irradiation device.