JPH0523062B2 - - Google Patents

Description

[Detailed description of the invention] (Technical field) The present invention relates to a method for detecting wafer chips.

(Background Art) Among automatic mounting machines for electronic components, die bonders for wafer chips and the like particularly require positional accuracy, and in order to meet that accuracy, it is necessary to confirm the position and shape by visual recognition.

FIG. 3 shows the state of the wafer chip before mounting, and the wafer chip 1 is made by cutting a silicon slice placed on an adhesive-coated transparent sheet 3 into a lattice pattern vertically and horizontally, and then expanding and separating it using an expander ring 4. It is obtained by Further, a butt mark 2 is previously attached to the wafer chip 1 to indicate a defective product.

By the way, chip recognition in a die bonder is performed according to the following steps: determining the shape of the chip (chip, crack, etc.), detecting a butt mark, and measuring the position of a good chip.

Next, the conventional recognition method will be explained: (i) As shown in FIG. 4A, a silhouette image I of a wafer chip is captured by an iTV camera using transmitted illumination.

(ii) The shape, position and orientation of the wafer tip are measured using the silhouette image I (FIG. 4B).

(iii) Next, for the wafer chip whose shape is determined to be good, a detection area S for detecting the butt mark 2 on the surface is created at a relative position to the wafer chip (FIG. 4C).

(iv) The illumination is switched to epi-illumination, the wafer chip is imaged, and the butt mark 2 is detected by checking whether or not the butt mark 2 is within the detection area S.

As described above, in the conventional method, in order to detect a bud mark, it is necessary to set a detection area at the relative position of each wafer chip or to correct the position of the detection area, which takes time.

(Object of the Invention) The present invention has been proposed in view of the above points, and its purpose is to facilitate the creation of a detection area for detecting butt marks, simplify hardware and software, and The purpose is to enable faster detection.

(Disclosure of the Invention) The chip recognition method according to the present invention will be explained below with reference to the drawings.

FIG. 1 shows the configuration of a detection device embodying the present invention. In the figure, 1 is a wafer chip, which is placed on a wafer ring 5.
Bad chips are marked with a butt mark 2 in advance. On the other hand, 8 is an iTV camera, and transmitted illumination 6
Alternatively, the wafer tip is imaged by illumination using epi-illumination 7. A video signal obtained from the iTV camera 8 is binarized in a binarization section (A/D) 9, and is inputted to an arithmetic section 12 and a reduction circuit 13 via a gate 11. Note that a signal is applied to one end of the gate 11 from the detection area generation section 10, so that only images within a necessary area pass through the gate 11. Also,
The calculation unit 12 performs shape determination from the obtained binarized image, and the calculated value obtained by image processing is directly compared with the non-defective level to determine the shape.

The reduction circuit 13 is a characteristic part of the present invention,
The silhouette image of the wafer chip 1 captured by the transmitted illumination 6 is reduced by a set number of pixels, and the reduced silhouette image is stored in the frame memory 14. Next, the reduced silhouette image stored in the frame memory 14 is applied to one end of the gate 15, and the image is captured by epi-illumination 7 to form the butt mark 2.
It is now being used as a detection area when detecting. Then, the calculation unit 16 is operated by the gate 15.
Image processing is performed on the signal that has passed through, and it is determined from the calculated value whether or not the bud mark 2 exists.

Therefore, the operations are listed in order: (i) First, as shown in FIG.

(ii) Using the silhouette image I, the shape, position and orientation of the wafer chip 1 are measured in the calculation unit 12 (FIG. 2B).

(iii) Next, the silhouette image I is reduced in the reduction circuit 13 to create a reduced silhouette image I' and stored in the frame memory 14.

(iv) Detect the memorized reduced silhouette image I′ in the detection area
I'', and the bud mark 2 is detected from the image captured by the iTV camera 8 using the epi-illumination 7.

becomes.

(Effects of the Invention) As described above, in the present invention, the detection area is created by reducing the silhouette image of the wafer chip. Alternatively, it is possible to eliminate the need for special hardware-based means and time-consuming methods, thereby enabling high-speed detection using simple hardware.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a detection device embodying the present invention, FIG. 2 is an explanatory diagram of its operation, FIG. 3 is an explanatory diagram of a wafer tip, and FIG. 4 is an explanatory diagram of a conventional detection method. 1...Wheel tip, 2...Bud mark, 5
... Wafer ring, 6 ... Transmitted illumination, 7 ... Epi-illumination, 8 ... iTV camera, 9 ... Binarization section (A/
D), 10... detection area generating section, 11, 15...
...Gate, 12, 16...Arithmetic section, 13...Reducing circuit, 14...Frame memory, I...Silhouette image, I'...Reduced silhouette image, I''...Diversion detection area.

Claims (1)

[Claims] 1. Determine whether the shape of the wafer tip is good or not, and
In a wafer chip detection method that detects a butt mark indicating a defect on the surface and detects the position data of a good chip, the silhouette image of the wafer chip captured by a television camera is reduced by a set number of pixels when determining whether the chip is in good shape or not. A method for detecting a wafer chip, characterized in that this reduced silhouette image is stored in a frame memory, and the stored reduced silhouette image is used as a detection area for detecting a butt mark.