JP2000243763A - Method for picking up semiconductor chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out efficient pick-up works by shortening image recognition time. SOLUTION: In a method for picking up a semiconductor chip which picks up a chip 6 on a wafer sheet 5, in a step of recognizing an image for detecting a position of the chip 6, two large and small search areas having different sizes are established in an image pick-up visual field, and when a detection of a position of the chip 6 of a single wafer sheet is made in a prescribed sequence, if the position of the single chip 6 is detected normally, in a detection of a position of a semiconductor chip to be recognized at a time subsequent to the chip 6, the small search area is used. Thus, frequencies of using the large search area are decreased, and a recognition time is reduced, so that image recognition can be performed efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor chip pickup method for picking up a semiconductor chip cut from a wafer and attached to a wafer sheet.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, a semiconductor chip is cut out from a wafer composed of a large number of individual chips. The individual chips are cut out with the wafer attached to an adhesive wafer sheet, and the cut individual chips are peeled off from the wafer sheet and picked up. In this pickup step, the individual chips are held by the pickup head in a state of being pushed up by pins from the lower surface side of the wafer sheet. For this reason, it is required that the semiconductor chip to be picked up be accurately positioned at the pick-up position so that the semiconductor chip can be correctly pushed up by the pins during the pick-up.

[0003]

Conventionally, image recognition has been used for position detection for this alignment, and the image picked up on a wafer sheet is subjected to pattern matching with a pattern of a reference semiconductor chip. Position detection was performed. In this image recognition, position detection is performed by searching a screen within a preset search processing target range, a so-called search area.
The size of the search area is related to the required search time, and the larger the search area, the longer the image recognition time. Therefore, in order to improve the efficiency of image recognition, a smaller search area may be set.

However, due to the variation in the amount of elongation of the wafer sheet when the wafer sheet is stretched after cutting the wafer, the arrangement of the semiconductor chips on the wafer sheet is not always a regular arrangement at a constant pitch. For this reason, conventionally, when recognizing an image of a semiconductor chip at the time of pickup, a large search area has to be set in order to prevent occurrence of a recognition error, and as a result, it takes a long time for image recognition. .

Accordingly, an object of the present invention is to provide a semiconductor chip pickup method capable of performing an efficient pickup operation while shortening the image recognition time.

[0006]

According to the present invention, there is provided a semiconductor chip pick-up method for picking up a semiconductor chip attached to a wafer sheet in a predetermined pattern by a pick-up head. When a plurality of search areas having different sizes are set in the imaging field of view in the image recognition step of detecting the position of the semiconductor chip, the position of the semiconductor chip on one wafer sheet is detected in a predetermined order. If the position of the chip is normally detected, the smaller search area is used for detecting the position of the next recognition target semiconductor chip following the semiconductor chip.

According to the present invention, if the position of one semiconductor chip is normally detected, a smaller search area is used for detecting the position of the next recognition target semiconductor chip following the semiconductor chip. Image recognition can be made more efficient by reducing the frequency of using a large search area.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a semiconductor chip pickup device according to an embodiment of the present invention;
2 is a functional block diagram of the semiconductor chip pickup device, FIG. 3 is a flowchart of the semiconductor chip pickup method, and FIGS. 4A and 4B are image diagrams showing search areas of the semiconductor chip pickup device. It is.

First, the structure of a semiconductor chip pickup device will be described with reference to FIG. In FIG. 1, a chip supply unit 1 is configured by connecting a wafer holding table 4 on a bracket 3 erected on an XY table 2. A semiconductor chip 6 (hereinafter, referred to as a semiconductor chip 6)
A wafer sheet 5 to which a number of "chips 6" are attached is mounted. An ejector unit 7 is provided below the wafer holding table 4. The pins 7a of the ejector unit 7 are aligned with the pickup positions of the chips 6, and the chips 6 on the wafer sheet 5 are pushed up by projecting the pins 7a upward.

A pickup head 8 mounted on a moving table 9 is disposed above the chip supply section 1 so as to be horizontally movable. The chips 6 pushed up by the pins 7a are evacuated by the nozzles 8a of the pickup head 8. Picked up by suction. The picked-up chip 6 is moved by the moving table 9 and the holding table 1
The work 11 is mounted on the work 11 placed thereon.

Above the wafer holding table 4, an image pickup section 12 having a camera 13 is provided. Imaging unit 12
Captures an image of the chip 6 on the wafer sheet 5, and image data obtained by the imaging is transmitted to the image recognition unit 14.
The image recognition unit 14 performs image processing on the image data and detects the position of the chip 6. The CPU 15 is an overall control unit that receives the recognition result of the image recognition unit 14 and controls each unit described below.

The storage unit 16 stores various data such as programs necessary for the operation of each unit, the size of the chip 6 to be recognized, and array data on the wafer sheet 5. The pickup head driving unit 17 drives the pickup head 8 and the moving table 9 for moving the pickup head. The ejector driving section 18 drives the ejector unit 7. The XY table driving section 19 drives the XY table 2. The display monitor 20 displays a captured image of the chip 6 and a screen for operation and input. The key input unit 35 is an input device such as a keyboard, and performs operation input and data input.

Next, the processing function of the semiconductor chip pickup device will be described with reference to FIG. 2, a chip size storage unit 21 and a chip arrangement state data storage unit 22 correspond to the storage unit 16 shown in FIG. 1, and include a recognition area setting unit 23, a statistical processing unit 24, a displacement correction processing unit 25, and a pitch. The feed processing unit 26 is a CPU
15 shows the processing performed. Image recognition unit 1
From the position data of the chip 6 detected by the step 4, the position deviation amounts Δx and Δy of the chip 6 in the orthogonal coordinate axis direction and the angle deviation amount Δθ of the rotation direction are obtained. Angle deviation Δθ
Is transmitted to the pickup head driving unit 17, and when the pickup head 8 is driven by the pickup head driving unit 17, the chip 6 is picked up by correcting the angle shift amount Δθ.

The displacement amounts Δx and Δy are transmitted to a displacement correction processing unit 25. The position shift correction processing unit 25 uses the pickup head 8 to move the chip 6 on the wafer sheet 5
The amount of misregistration correction when picking up
The signal is transmitted to the table driving unit 19. Also, the displacement amount Δx,
Δy is also transmitted to the statistical processing unit 24, and the statistical processing unit 24 calculates a learning value of an average positional deviation amount based on the data of the positional deviation amounts Δx and Δy accumulated in the past. The learning value of the displacement amount obtained here is sent to the pitch feed processing unit 26, and the pitch feed processing unit 26 determines the pitch required to position the chip 6 to be next picked up at the center of the image screen by the camera 13. Calculate the feed amount. This calculation is performed by the CPU 15 based on the learning value described above and the array pitch data of the chips 6 stored in the chip array state data storage unit 22.
It is performed by

The recognition area setting unit 23 sets a range to be recognized in image recognition, that is, a search area, based on the recognition result of the image recognition unit 14 and data of the chip size and the chip arrangement pitch. The search area set here will be described with reference to the image diagram of FIG. Screens 30 and 31 shown in FIGS. 4A and 4B respectively show two types of search areas, large and small. The screen sizes WXmax and WYmax of the large search area 30 are set to be about twice as large as the arrangement pitches PX and PY of the chips 6. On the other hand, the screen size WXmin, WYmin of the small search area 31 is the chip size X1,
It is set to a dimension obtained by adding twice the gap width between chips X2 and Y2 to both sides of Y1.

As described above, the search area is preset in two sizes, large and small, according to the chip sizes X1, Y2 and the arrangement pitches PX, PY obtained by adding the gap widths X2, Y2 to the chip sizes X1, Y2. At the time of detection, either a large or small search area is selected. The magnitude setting is determined by the recognition result of the image recognition unit 14.

The selection of the search area in the image recognition of the chip will be described below with reference to the flowchart of FIG. The flow of FIG. 3 shows the processing from the state where the wafer sheet 5 is newly mounted on the wafer holding table 4, and the position of the chip 6 on the wafer sheet is not actually grasped at the beginning of the mounting. Therefore, the setting of the search area is set to "large" (ST1). Next, the presence or absence of a chip to be picked up is confirmed (ST2). If there is a chip, the chip to be picked up is sent to the pickup position at a pitch (ST3). This pick-up position is the pick-up start position specified on the wafer sheet 5 immediately after the wafer sheet exchange, and after the pick-up process starts, the pick-up position moves sequentially according to the specified pick-up order.

When the chip to be picked up is sent to the image pickup position, the camera 13 picks up an image of the chip position and recognizes it (ST4). If the recognition is successful in this recognition, that is, if the position of the chip to be picked up is normally detected (ST5), the XY table 2 corrects the position shift of the chip 6 based on the position shift data obtained from the position detection result. Is driven to drive the chip 6 to the pickup position (ST6). Then, after the chip 6 is pushed up by the pin 7a of the ejector unit 7, the chip 6 is picked up by the pickup head 8 (ST7). Then, the setting of the search area is switched to "small" (ST8), and the process returns to ST2 to repeat the same processing.

If the recognition is not successful in ST5, that is, if the position of the chip 6 is not normally detected, the setting of the search area is confirmed. If the setting is "large", the process returns to ST2 as described above. In other words, if the recognition is unsuccessful using the large search area, the chip is left and the next chip to be picked up is recognized. If the setting is "small", the setting is set to "large" (S
T10). After that, returning to ST4, the chip recognition is performed again,
The processing after ST5 is repeated. Then, in ST2, the recognition of all the chips on the wafer sheet 5 is completed, and if it is confirmed that the unrecognized chips are out of stock, the pickup operation is ended.

In this embodiment, a plurality of search areas having different sizes are used as the screen size WX described above.
Although two types of max, WYmax, WXmin, and WYmin are set, the present invention is not limited to this. For example, three or more types of a plurality of search areas having different sizes are set and the position is set. If the detection is normally performed, a smaller search area among the plurality of search areas may be used.

As described above, in the present embodiment, a plurality of search areas having different sizes are set in the field of view of the image pickup, and when detecting the position of a chip, if the position of one chip is normally detected. The smaller search area is used for searching for the position of the next recognition target chip following the chip. The fact that the position of the chip was detected normally means that the probability that the chips are arranged according to the normal pitch is high, at least in the vicinity of the chip, and therefore, even if a small search area is used, recognition is successful. The probability is high, the recognition time can be shortened, and the efficiency of image recognition can be improved.

[0022]

According to the present invention, if the position of one semiconductor chip is normally detected, a smaller search area is used to detect the position of the next recognition target semiconductor chip following the semiconductor chip. Therefore, the frequency of using a large search area can be reduced, the recognition time can be shortened, and the efficiency of image recognition can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a semiconductor chip pickup device according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of a semiconductor chip pickup device according to one embodiment of the present invention;

FIG. 3 is a flowchart of a semiconductor chip pickup method according to an embodiment of the present invention;

FIG. 4A is an image diagram showing a search area of a semiconductor chip pickup device according to one embodiment of the present invention; FIG. 4B is an image diagram showing a search area of a semiconductor chip pickup device of one embodiment of the present invention;

[Explanation of symbols]

 Reference Signs List 5 Wafer sheet 6 Chip 8 Pickup head 13 Camera 14 Image recognition unit 15 CPU

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Ariyoshi 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5F047 FA08 FA73 FA75

Claims (1)

[Claims] 1. A method of picking up a semiconductor chip attached to a wafer sheet in a predetermined pattern by a pick-up head, wherein an imaging field of view is detected in an image recognition step of detecting a position of the semiconductor chip on the wafer sheet. When a plurality of search areas having different sizes are set within the semiconductor device and the position of one semiconductor chip is normally detected when the position of the semiconductor chip on one wafer sheet is detected in a predetermined order, A method for picking up a semiconductor chip, wherein a smaller search area is used for detecting the position of a semiconductor chip to be recognized next time after the chip.