JPS584938A - Wire bonding system - Google Patents

Abstract

PURPOSE:To detect deviation from right fixing positions and to compensate therefor, when a wire bonding is performed wherein a wire connection is established by means of a pressure fixing ball between the pad of a semiconductor chip stuck on a mounting platform and a pad belonging in the mounting platform, by a method wherein an image pickup device located immediately above them monitors the connecting work and the output therefrom is displayed after binarization. CONSTITUTION:A semiconductor pellet 1 with a pad 2 is stuck on a platform 10 and is connected to a pad 5 installed on the platform 10 with a wire 4 by means of a pressure fixing ball. Under this construction, an image pickup unit 12 with a lens system 11 is positioned opposing the pressure fixing ball. The unit 12 is driven by a driving circuit 13 and yields an output that is binarized in a pre- processing unit 14 and then is stored in an image memory 15. Next, signals read out of the memory 15 are supplied to a scanning line setting circuits 17A and 17B, X-Y scanning circuits 20A and 20B, etc. The detecting circuit 21 detects if the pressure fixing ball is located at the central position and, if not, an output unit 23 is activated and adjusts the ball position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention Wi4 is connected to a wire bending device, in particular, detects the displacement of the crimping position of a wire thermally bonded to a pad of a semiconductor chip and corrects the crimping position during wire bonding. This invention relates to an automatic wire bonding device for noodles.

When gold wire is fused to the pad portion of a semiconductor chip using a pressure bonding pool, the center positions a and b of the plurality of pads 2 arranged at the circumference of the semiconductor chip l: MJ as shown in 1lllli.
With the reference point as the reference point, the inspection area is limited to the area crossed by WI in square 6, and along the outer periphery overlapped by 11 in ζO square, *scanning line $ is set, and the wire 4t-scanning line, which is the gold wire Il, is set. It is possible to detect the point 9 where the ball is pressed.
In order to detect the amount of displacement of the crimping position of the wire 40 between the secondary pad 5t and the secondary pad 5t-pt, a device is known in which the width W of the crimping lug is determined by scanning the central hand IIO at a distance of 7.7 K.

In this way, the crimping position deviation detection means of 1 adds the video signal from the imaging device to the binarization processing circuit to capture the video of the 114 part of the semiconductor chip 2, and binarizes the video signal of the semiconductor chip 2. The vicinity of pad 3, which is the object to be recognized, is stored in the binarized memory.

The output of the binarized video memory detects the crimp portion on the pad, that is, the width W of the crimp, based on the scanning line setting circuit and the pad center position address i.

When the pole width W of the crimping part 30 with the conventional configuration as described above is scanned along the scanning line 7, Wl and mat are found in the crimping part 1 ball.
, , giving rise to the drawback of outputting erroneous needle side results.

The present invention provides a crimping width detection device that eliminates the above-mentioned drawbacks, and also provides a fully automatic wire bonding device that detects when crimping is in progress and corrects the misalignment of the crimping part with respect to the pad. be.

The details of the present invention will be explained below with reference to FIGS. 31@1 to 9.

5ell shows a system diagram of the fully automatic wire bonding apparatus of the present invention, in which an object to be recognized such as a semiconductor chip is placed on a loading stage 1G, and the surrounding area of the semiconductor chip 1 is
It has multiple pads 2 of 400 to 5 degrees
00710mm secondary pad 5 between 30#ψ@degree gold-
The wire 4 is heat-sealed. For this purpose, the wire 4 is crimped and fixed to the pad 2 via the crimping ball 3. Before such wire bonding, it is necessary to properly bond the crimp pole 3 to the center position of the pad 2. Therefore, in the present invention, the pad 2 portion of the semiconductor chip 1 is connected to the imaging device 12.
The video signal near the pad 2 of the chip 1 is applied to the preprocessing circuit 14 through the lens system lit, and is binarized. Sho 13
The output of the 0 preprocessing circuit 14, which is a drive circuit for the weaving device 12, is stored in a binarized video memory 15.

For example, as shown in FIG. 114, the value conversion memory 15 stores the inspection area 6 in the vicinity of the bad part of the semiconductor chip l.

Note that 7.8 shows lf4 in the state of 49 of the cross-shaped scanning line and the scanning line portion along the outer periphery of the inspection area. tSF1
Each block is controlled by a control circuit.

The output of the binarized video memory 15 is applied to the first and second scanning line setting circuits 17M and 17B. The first and second scanning line setting circuits are given a signal from the pad center position address 18. A scanning line is set along the inspection area of the semiconductor pad 2. When setting the scan Im, it is explained that the scanning line is set along the outer periphery of the defined inspection area. Therefore, the pad center positions a and b are stored in the pad center position address 18, and may be appropriately set around the pad 20 using this address.

In the present invention, the first scanning line setting circuit 174 scans the scanning line 8 as shown in FIG. Scanning is performed by the scanning line setting circuit 17B. Detection of the presence or absence of the wire 4 during scanning @8m or 8B is performed by the next stage 1ml and second wire signal detection circuits 19&, 19B. The wire signal detection circuits 19A and 19B scan the scanning line 8 which scans the scanning IsB of the binary video memory shown in FIG. 4 as determined by the first scanning line setting circuit 17A. (Same as determined by the second scanning line setting circuit 17B)
The scanning line 8B is applied to the scanning line 8 portion of the binarized video memory. If the scanning lines 8A, 8B and the wire 4 intersect at multiple points 9m or tj9B, the binarized signal of the binarized video memory shown in FIG. The value signal displays "1%".

As shown in FIG. 7, a specific circuit for detecting a wire signal is such that the successive data of nine scanning lines 8A and 8B are input to the data input terminal 19c and passed through an n-bit shift register 19dt. Data output terminal 19
The comparison circuit 19hK receives the number of z-valued signals It extracted from the reference bits and successively appears from the 8-pit priority encoder 19f, for example. Since the scissors comparison circuit 19hK is given a binary signal from the reference circuit 19g with the number of bits corresponding to the thickness of the wire 4 as a reference value, the binary signal continuously appearing from the reference bits is compared with the reference value. The presence or absence of wire 4 is the output terminal 1.
9JK is taken out. If there is a signal from the output terminal 19J as described above, the first
Alternatively, the second cross scanning circuit 20A or F120B is activated.

That is, when it is confirmed that the wire 4 is present on the scanning line 9A, the center point (a, b) of the pad 2 as shown in FIG.
), and if it is confirmed that there is a wire 4 on the scanning line 9B, then the inspection is performed centering on the center point (a, b) of the pad 2 as shown in Figure 9. Orthogonal scanning 7 is performed between opposing sides of region 60. In this way, the width W of the crimp ball 3 can be accurately measured.

That is, by using such a measuring means, it is possible to avoid the front error needle #1 as shown in FIG.

The outputs of the cross scanning circuits 20 and 20B are the width of the crimp ball 3.The crimp ball center detection circuit 21 detects the center and calculates the amount of deviation from the center of the pad 2 (a, b) to the center of the crimp ball 3. A calculation is performed at 22 and the result is provided to an output device 23.

Add this amount of deviation to the wire bonding equipment and place it on the mounting table 1.
The tire bonding position is corrected by moving it in the iXY direction such as 0.

In the above embodiment, the scanning lines 8M and 8B are divided at a ratio of <1:2:1 on one side of the scanning line 8 as shown in FIG. 5, but these values can be selected as appropriate division ratios.

The present invention is constructed as described above, and since the width Wf of the crimp ball 3 is
It has a 4I image that can be detected without error and can automate the wire bonding equipment without malfunction.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the relationship between the vicinity of a conventional semiconductor pad and a crimp ball, and FIG. 2 is a plan view of a pad portion for explaining the disadvantages when measuring the width of a crimp pole. FIG. 3 is a system diagram of a wire bonding apparatus according to the present invention. 4 is a diagram of the binarized video memory used in FIG. 3; FIGS. 5 and 6 are plan views of the vicinity of the pad showing the scanning method of the present invention; FIG. 7 is an example of a wire signal detection circuit; 8 figures and! FIG. 9 is a plan view of the vicinity of the rad for explaining the scanning method of the present invention. l...Semiconductor chip 2. Pad 3. Crimp ball 4. Wire 5. Secondary J (rad 6 Inspection area 7.8 Scanning line 10.・・・
Mounting table 11.・−・− Lens system 12.・・・・・・
. . . Imaging device 14, . . . Preprocessing circuit 3s, -
...Binarized video memo Q 17A, 17B...
...First and second scanning line setting circuits 18.・・・・・・
- Pad center position address 19, A, 19. B-,
...III and second wire signal detection circuit 20m, 20
B...Cross scanning circuit 21,...Crimped ball detection circuit 2λ...--Arithmetic circuit 23.・・・
...Output device Fact 1 Figure 2 Figure 4 Figure 5 Figure 6 Flash 7 Figure 8 Blue 9.

Claims (1)

[Claims] A binarized video memory that records the entire wire bonder portion of the semiconductor chip and stores the crease binarized output, a pad center position address memory, and the binarized video image. Based on the center position address memo 9, the above pad O
The presence or absence of a wire is detected by scanning the binarized video memo IJ based on the scanning of the scanning line setting means and the cross scanning line setting means for setting a scanning line in the inspection area of jI:i11. a means for detecting the presence or absence of a wire; a means for setting a scanning line that passes through the center position of the pad within the inspection area based on the output of the sensor; means for determining the center of the wire crimping part; means for determining the deviation between the center position of the pad and the center of the wire crimping part; and the amount of deviation of the crimping part.
Wire bending device comprising means for correcting the crimp position of the wire