JPH03209739A - Board inspecting equipment - Google Patents

Abstract

PURPOSE:To reduce the number of times of measurement, simplify human work, realize automating, and dissolve damage of a land caused by a probe of a resistance measuring apparatus, by inspecting the connection state of a substrate wiring by using a scanning electron beam microscope and a DC power supply. CONSTITUTION:In an SEM equipment 72, the primary electron beam is converged by a lens 2; the secondary electrons generated by two-dimensionally scanning the package 10 surface with a deflection coil 3 are detected by a secondary electron detector 4; a obtained signal is amplified by a signal amplifier 5, and displayed on a CRT 6. In a POGO pin designating part 16, a relay controlling equipment 7 designates a POGO pin 13 to which a DC voltage is to be applied. A relay selecting circuit 17 makes A relays 18 in a relay box 14 open and shut so as to connect the designated POGO pin 13 and a DC power supply 8. For example, when only the stitch 1(20) linking with the designated POGO pin 1 is darkly observed on the CRT, and all other stitches are brightly observed, it can be recognized that the substrate wiring linking with the stitch 1 is not disconnected and does not short with other wirings.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is directed to the connection state of wiring on a board that connects a large-scale integrated circuit (hereinafter referred to as LSI) and an LSI testing device (hereinafter referred to as LSI tester). It concerns inspection.

[Conventional technology]

LSIs are usually tested using an LSI tester. 7th
The figure is an exploded perspective view showing a state of connection between a conventional LSI and an LSI tester. LSI tester (39) is LSI
(34) to detect the electrical signal output from the LSI (34) to check whether the circuit built into the LSI (34) operates normally.

+, The package containing S engineering (34) is the board (1
It can be attached by inserting the package pin (35) into the socket Oυ of the housing. When the pogo pin [13 contacts the board C13, the LSI fsll (39) and the LSI
(34) are electrically connected. Test head (36)
connects the electric signal from the driver (37) to the pogo pin (131).
It also serves to transmit the electrical signal output of the pogo pin (L S r C34 transmitted to 13) via the board U to the comparator (38).

FIG. 8 (at (bl) shows a cross-sectional view and a plan view of the board (12). The pogo pin αJ of the LSI tester (39) is in contact with the land LL (41) of the board Qz.
All lands and socket pins are connected to land Ll (41
) and socket pin Pi (43) are printed wiring h (
42), all of them are connected in an l-to-l combination.

FIG. 9 (al(b)) shows a plan view and a sectional view of the package (to) in which the LSI is enclosed.The package pin (35) is connected to the stitch (44) in a one-to-one combination. .In the above manner, the LSI tester (39)
The electrical signal from the LSI (34) is transmitted to the LSI tester (39), and the electrical signal from the LSI (34) is transmitted to the LSI tester (39).
) is transmitted.

Inspection of the board (1z) used to connect the L Sr7
This is an explanatory diagram showing a conventional inspection method for 1z.
a2 is the board, (41) is the land t, (43) is the socket bin P1, (49) is the land L2, (50) is the socket pin P2, (47) is the resistance measuring device, (48) is the resistance measuring device It is a probe of.

FIG. 11 shows a flowchart of a conventional disconnection inspection device for wiring on a board (1z). In the figure, step 51 is the initial setting of the land number, and step 52 is the initialization of the land number. = Ll)
and socket bit Pi (when i = 1, Pl = P
Step 53 is a determination operation of determining whether there is a conduction state from the resistance measurement result, Step 54 is a determination result (PAss), (5
5) shows the determination result (FAIL). If the judgment result is PASS, that is, the measured resistance value is small and it is in a conductive state, the wiring on the board C1z is not disconnected, and the quick result is FAZL in step 55, that is, if the measured resistance value is large and it is not in a conductive state. , board (one wiring is broken. Step 56 is a judgment as to whether the land number is equal to the number of wirings n. If not, proceed to step 57. Step 57 is to increase the land number by one. This means that if they are equal, the test is complete.

As can be seen from the flowchart in FIG.
If the number of wires in No. 2 is n, the resistance measurement (manual work) will be performed n times. FIG. 12 shows a flowchart of a conventional short-circuit inspection between wiring on a board (lz). In the figure, step 58 is the initial setting of the land number, and step 59 is the initial setting of the land number, and step 59 is to move the probe of the resistance measuring instrument to the land u (when i=l, Li =Lt) and the land (when J=2 = L2) and measure the resistance value.Step 60 is a judgment operation of determining whether or not there is continuity from the resistance measurement result.Step 6
1 indicates the determination result (PAEI8), and step 62 indicates the determination result (FAIL). If the judgment result is PASS, that is, the measured resistance value is large and there is no continuity, there is no short circuit between the wires connected to the land that was touched by the probe, and the judgment result is FArL, that is, if the measured resistance value is small and it is in the continuity state. is shorted. Step 63 is a determination as to whether a parameter J specifying a land (wiring) is equal to n. Step 64 is to increase parameter J by one. If parameter j is not equal to n, proceed to step 64, otherwise proceed to step 65
Proceed to. The step is to determine whether parameter 1 specifying a land (wiring) is equal to n. If not, proceed to steps 66 and 67. Step 66 is to make the parameter J equal to 1+2, and step 67 is to increase the parameter J by one. If they are equal, the test is finished. As can be seen from the flowchart of FIG. 11, when the number of wires on the board α2 is n, the resistance measurement (manual work) is performed n02 times.

[Problem to be solved by the invention]

Since the conventional board inspection equipment is configured as described above, if the number of wires on the board (1z is n), the number of measurements is n times for wire breakage inspection, and n C2 times for short circuit inspection between wires, for a total of n+nCz measurements are required.Furthermore, if the number of wires on the board is large, the number of measurements increases, especially when testing short circuits between wires, and all inspection work is done manually. As a result, the inspection time becomes longer, the number of times the probe of the resistance measuring device comes into contact with the land of the board increases, and the land is damaged by the probe.

This invention was made to solve the above-mentioned problems, and aims to reduce the number of measurements during inspection, simplify and automate manual work, and eliminate land damage caused by the probe of a resistance measuring instrument. With the goal.

[Means to solve the problem]

The board inspection device according to the present invention can simultaneously test for disconnections in the wiring on the board and for short circuits between the wiring on the board, and reduce the number of measurements in the test compared to conventional testing methods. This eliminates damage to the land caused by contact of the probe of the resistance measuring device with the land of the board in the conventional testing method, and also eliminates the manual work of bringing the probe of the resistance measuring device into contact with the land.

[Effect]

The board inspection apparatus according to the present invention uses an electron beam for inspection, and when the electron beam is irradiated onto the stitches of the package in which the wirings of the board are connected in a 1:1 ratio, secondary electrons are generated from the surface of the stitches. This secondary electron is detected by a secondary electron detector. Secondary electrons generated from stitches with low potential are secondary electrons generated from stitches with high potential.
Since they have higher energy than secondary electrons, more of them reach the secondary electron detector. Therefore, stitches with a low potential appear brighter on a CRT than stitches with a higher potential.By observing multiple stitches on a CRT, it is possible to simultaneously determine the high and low potentials of multiple stitches on a CRT. becomes. In the conventional inspection method, short-circuit inspection between wires on a board requires measurement n02 times [n: number of wires] because the measurements are in one-to-one correspondence, whereas the test according to the present invention requires multiple stitches. (These are connected one-to-one to the wiring on the board) It is possible to simultaneously observe the high and low potentials, so the number of observations is n times. Therefore, inspection of the board (inspection of disconnection of wiring and inspection of short circuit between wiring) can be completed with n observations. Roughly speaking, since the pogo pin from the voltage generator contacts the land of the board only once, mechanical damage to the land is negligible compared to conventional inspection methods.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is an explanatory diagram of a board inspection apparatus according to an embodiment of the present invention. In the figure, (1) is an electron gun, and (2) is an electron gun (
1) A lens for focusing the generated electron beam,
(3) is a deflection coil for deflecting the electron beam, (4
) is a secondary electron detector, (6) is a signal amplifier, (6) is S
CtFIT for observing EM images, (7) is a relay control device, (8) is a DC power supply, (9) is a vacuum exhaust system (10)
) is a package for enclosing the LSI, qυ is a socket for inserting the package (lO), α2 is a board,
(13 is a pogo pin for applying voltage to the board (12), (14) is a relay box with pogo pin (13), (15) is a moving mechanism. In Fig. 2, (
16) is the pogo pin specification section, (17) is the relay selection circuit, (18) beam l/-, (19) is the resistance (the number is Ω)
, (72) is an S-mark M device.

This board inspection device includes an SEM device (72), a relay box (14), an IJ relay control device (γ-n, and a DC power supply (
8) mainly due to structure Fi5. be done. SEM equipment (72
), whose configuration is shown in Figure 1, is that the primary electron beam generated from the electron gun (1) is transmitted through the lens (2) into several hundred six (IA
The secondary electron detector (4) detects the secondary electrons generated by scanning the surface of the package (to) two-dimensionally with the deflection coil (8), and the obtained signal is The signal is amplified by a signal amplifier (5) and displayed on a CRT (6) for observation of an 80M image.

Figure 2 shows the relay control device (7) and relay box (
141 connection diagram is shown. In the pogo pin designation part qe,
Specify the pogo pin (13) to which DC voltage is applied, and open/close relay ns+' in the relay box (141) using the relay selection circuit ση to connect the specified pogo pin t131 and the DC power supply (8).Relay box ( 14
The pogo pin CI3 of No. 1 is the same as that of the pogo pin of the LSI tester (39). As shown in Figure 1, the substrate (1z
is set in the SIluM device (72) and inspected. Board (1z socket) (111 has LSI (3
4) The package is attached except for the unsealed lid.

FIG. 5 shows a flowchart of inspection of wiring on a board by the board inspection device. In the figure, step 22 is a substrate (12
) to the equipment, step 23 is a vacuum work to evacuate the inside of the equipment, and step 24 is to turn on the DC power supply (8) to generate a positive voltage.
N work, Step 25 is the initial setting of the pogo pin number, Step 26 is the pogo pin designation in the pogo pin designation section qe, Stitch 27 is the selection of the relay selection circuit (171 Nyorori 1/-), Step 28 is the observation of the potential contrast of the stitch. The stitches of the pogo pin C13 and the package (to) are connected on a one-to-one basis.Step 29 is a judgment operation to judge whether the stitch line connected to the specified pogo pin i appears dark on the CRT. As shown in Figure 3, if only stitch 1■ connected to the specified pogo pin 1 appears dark on the CRT and all other stitches appear bright, the wiring on the board connected to stitch 1 is not disconnected, and other It turns out that there is no short circuit with the wiring, and in this case, connect the board wiring connected to pogo pin 1 to P.
Register as an ASS (step 30). For example, as shown in Figure 4, stitch 1 (
2G and stitch 2 that connects to pogo pin 2 (2D is CR
If the stitches on the T look dark and the other stitches look bright, it means that the wiring on the board connected to stitch 1 and stitch 2 (211) is short-circuited. In this case, connect the wiring on the board connected to pogo pin 1 to FAIC. (Step 3
Register as 1).

Step 32 is to determine whether the parameter 1 that specifies the pogo pin (13) connected to the stitch is equal to the number n of wires on the board. If the parameter i is equal to the number n of wires, the observation is completed. Step 33 is the parameter 1 to 1
The goal is to make it bigger.

As can be seen from the flowchart in FIG. 5, when the number of wires is n, the number of observations is
It turns out that it will end in 30 minutes.

In addition, although the case of the board|substrate inspection apparatus was demonstrated in the said Example, the case of a wafer probe card may be sufficient, and the effect similar to the said Example is produced. FIG. 6 (al (bl) shows a cross-sectional view and a perspective view of a sea urchin/X probe card, which is another embodiment of the present invention. In the figure, (68) is a sea urchin probe card board, and (69) is a sea urchin probe card board. Rand, (70
) indicates a probe needle, and (71) indicates a printed wiring. L.S.
I tester (39) pogo pin (131 is land (69)
The tip of the probe needle (70) touches the LSI (34)
By contacting the pad (45), the LSI tester (39) and LSI (34) can be connected. Substrate U
Instead, by setting the wafer probe card in the substrate inspection device and observing the tip of the probe needle (70), it is also possible to test for disconnections in the wiring of the wafer probe card and for short circuits between the wirings.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to simultaneously observe the potential of all wirings, instead of one-on-one measurement between wirings as in the conventional inspection method using a resistance measuring device. Compared to the inspection method, this method has the advantage of reducing the number of measurements, reducing mechanical damage to the lands of the board due to measurements, and eliminating the need for the manual work of contacting the probes of the resistance measuring device with the lands.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a board inspection device according to an embodiment of the present invention, Fig. 2 is a connection diagram of the relay control device and relay box shown in Fig. 1, and Figs. 3 and 4 are board inspection diagrams shown in Fig. 1. An explanatory diagram of a SEM image (CRT screen) of the package surface observed with the device, FIG. 5 is a flowchart of board inspection by the board inspection device of FIG. 1, and FIG. FIG. 7 is an exploded perspective view showing the state of connection between a conventional LSI tester and LSm, FIG. (bl is a plan view and a cross-sectional view of a package in which an LSI is enclosed, FIG. 10 is an explanatory diagram showing a conventional inspection method for a board, and FIG. 11 is a 70-chart of a conventional disconnection inspection device for board wiring. , 12th
The figure is a flowchart of a conventional short-circuit test between wiring lines on a board. (1) is an electron gun, (2) is a lens, (8) is a deflection coil, (4) is a secondary electron detector, (6) is a signal amplifier, (6) is a
) is the CRT, (7) is the relay control device, (8) is the DC power supply, (9) is the vacuum exhaust system, is the package, qυ is the socket), (13 is the board, α3 is the pogo pin, (14 is the relay box) , west is the moving mechanism, (11) l is the pogo pin designation section, (Lη is the relay selection circuit, C181 is the relay, 9 is the resistor, ■ is the stitch 1, (211 is the stitch 2.
34) represents an LSI, and (35) represents a package pin. In addition, in the figures, the same symbols indicate the same parts. KoF't! 774 Steam culm Figure 3 Cause 4 5yA Field $P Figure 7 Figure 4 Engraving of the drawing Figure 8 (b') Figure 9 (Q) Figure 11 Figure 12 Procedural amendment (method) 1. Case Indication 2, Name of the invention Shinji Patent Application No. 2-4760 Board inspection device 3, Name of address related to the case of the person making the amendment Name 4, Address of the agent

Claims (1)

[Claims] A board inspection device that uses a scanning electron microscope and a DC power supply to test the connection state of wiring on a board in testing a board that connects a large-scale integrated circuit (LSI) and an LSI inspection device.