JPH04323836A - Semiconductor device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a semiconductor device that performs wire bonding.

0002

2. Description of the Related Art In the semiconductor manufacturing process, when assembling completed wafers, as shown in FIG. 8, the wafer 1 in (a) is separated into the individual chips 2 in (b). Thereafter, the chip 2 is die-bonded onto the frame 3 as shown in (c). Next, wire bonding is performed to the chip 2 attached to the frame 3. The method for performing this wire bonding is to photograph the chip 2 to which the wires are to be connected using a television camera 4 as shown in FIG. It is common practice to specify the location and bond. Conventionally, the aluminum wiring pattern on the chip surface has been used as a criterion for identifying the pad position to which a wire should be bonded through image processing.

0003

[Problem to be Solved by the Invention] However, aluminum wiring patterns have various shapes depending on the chip, and depending on the shape, image processing is difficult, and there are cases where many wire bonding defects occur or where image processing is not possible at all. was there. Particularly in devices where aluminum wiring patterns are present over the entire surface of the chip, it is extremely difficult to identify bonding pads.

The present invention has been devised in view of the above points, and it is possible to easily image process the aluminum wiring pattern, which is difficult to image process in the wire bonding process, and adjust the position of the bonding pad. The purpose is to reduce the defective rate of semiconductor devices by making it possible to clearly judge the failure rate of semiconductor devices.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention forms a mark for position recognition at a position where it enters the television screen of an image processing system in order to clarify the position of the wire bonding pad. do.

[0006]

According to this structure, the position of a predetermined wire bonding pad can be determined from the position recognition mark by image processing, so that the wire can be attached to the correct pad position.

[0007]

[Example] Figure 1 shows the chip surface of a MOSFET, where 6 is a source region, 7 is a source pad, and 8 is a source region.
is the gate pad. It is assumed that the drain pad exists on the back side of the chip. A thin white band-shaped portion 9 represents aluminum wiring. In this figure, the white areas are aluminum, and the black areas are areas where aluminum does not exist.

Reference numeral 10 is a mark provided on the source pad for recognizing the source pad, and 11 is a mark for recognizing the gate pad. If the left and right sides of the chip 2 do not fit within one TV screen at the same time, as shown in the figure, one pair is placed on the left side (gate pad 8 side in the case shown) and the right side (source 7 side in the case shown). A recognition mark is provided for each.

However, when both the left and right sides are included in one screen, the recognition mark can be shared between the left and right sides (that is, both sides), so it is sufficient to provide two recognition marks as shown in FIGS. 2 to 5. Note that the mark may be placed anywhere on the chip. Now, the size of chip 2 is 1 screen of a TV camera.
Assume that the size is enough to fit within 2.

Note that FIGS. 2 to 5 compare and show how large the marks 10 and 11 should be. First, in FIG. It shows the size of the block. The marks 10 and 11 in FIG. 3 are smaller, and the marks in FIG. 4 are even smaller. On the contrary, the mark in FIG. 5 is much larger than the mark in FIG.

In the case of FIG. 4, it is too small to be distinguished from noise such as dust 13, and is therefore useless. In the case of FIG. 3, it is also difficult to distinguish noise from large dust, so it is desirable to avoid it. In addition, although it can be used in the case of Figure 5,
It's too big and takes up too much space. It can be said that the size of the mark shown in FIG. 2 is appropriate in terms of the discriminative power required to recognize it and the area occupied by the chip 2.

[0012]Next, there are various methods of creating the marks 10 and 11, one of which is to apply a material different from aluminum. The second method is to use a protective film on aluminum. In other words, a protective film is generally applied on aluminum, but
By removing a portion of the protective film and providing it, the removed portion is used as a mark. The third step is to etch the aluminum. However, when using this etching, it is necessary to provide the pad portion or a portion of the chip that does not function as an element. It is possible to form marks by other suitable methods in addition to those described above.

Next, FIG. 7 shows a method for determining the position of a pad from two marks. Here, we will use two markers.
A(X1, Y1) and B(
X2, Y2), and the pad position C (X3, Y3) is determined by two predetermined distances r1, r2.
is specified as a point that satisfies the following. This is the processing section 5 (Fig. 9
This is done in software using a microcomputer program that makes up the software. The output of the processing section 5 controls the chip and the wire so that the attachment part of the wire is located at position C of the pad. Specifically, by moving the frame 3 (therefore the chip 2) in the X direction in FIG. 7 and moving the wire in the Y direction, the attachment portion of the wire is adapted to the position C of the pad.

As I said earlier, the mark is 2 on the screen.
As long as there is one, its location does not matter. Further, the number of marks does not necessarily have to be two, and may be one. This is a case where the edge portion of chip 2 can be used as one of the marks. FIG. 6 shows the bonding area 14 of the wire to the pad 7.

[0015]

[Effects of the Invention] As explained above, according to the present invention, since marks for position recognition are provided on the chip surface,
Image processing for specifying the bonding pad position is facilitated, and the positional accuracy of wire connections relative to the bonding pads is improved and variations are reduced. Therefore, there is an effect that the defective rate of semiconductor devices is reduced. Furthermore, in the past, the precision was poor and the size of the bonding pad had to be large, but with the present invention it can be made smaller. Furthermore, the marks can be used to identify and assemble patterns other than bonding pads, expanding and improving manufacturing performance.

[Brief explanation of drawings]

FIG. 1 is a plan view of a MOSFET chip implementing the present invention.

FIG. 2 is a diagram showing an appropriate size of the position recognition mark according to the present invention.

FIG. 3 is a diagram showing an example of the size of a position recognition mark according to the present invention.

FIG. 4 is a diagram showing an example of the size of a position recognition mark according to the present invention.

FIG. 5 is a diagram showing an example of the size of a position recognition mark according to the present invention.

FIG. 6 is a diagram showing the bonding area of a wire to a pad.

FIG. 7 is a diagram showing a part of image processing.

FIG. 8 is a diagram showing the procedure for creating a chip from Uheha.

FIG. 9 is a diagram showing an apparatus for identifying bonding pads on a chip.

[Explanation of symbols]

2 Chip 3 Frame 4 TV camera 5 Processing section 6 Aluminum 7. Pad for sauce 8 Gate pad 9 Aluminum wiring 10,11 mark 12 TV screen 13. Garbage

Claims (1)

[Claims] 1. A semiconductor device characterized in that a mark for position recognition is formed at a position on a television screen of an image processing system to clarify the position of a wire bonding pad.