JPH05126529A - Position detection method - Google Patents

Abstract

PURPOSE:To obtain a position-detection method which detects positions of objects in the order of sub mum to position the objects when mounting semiconductor devices on a wiring board. CONSTITUTION:A recognition mark where M-series signals are arranged two- dimensionally at an part of an object. An image which is obtained by picking up and confirming the recognition mark with a TV camera and a mark which is in a same reference as a previously stored recognition mark are correlated by the matching method and the position of the target is detected based on the result.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting method used when a semiconductor element is mounted on a wiring board.

2. Description of the Related Art Conventionally, when a semiconductor element or the like is positioned and mounted on a wiring board, an under camera for recognizing the wiring board and a top camera for recognizing the semiconductor element are used.
Further, when recognizing the wiring board and the semiconductor element, it is necessary to give the recognition mark to the wiring board and the semiconductor element without fail. The conventional recognition mark mainly uses a symmetrical figure like a triangle shown in FIG. 6a. The figure is photographed by a TV camera to capture an image, and pattern matching is performed with the same figure previously stored in the computer. ing.

There are various kinds of pattern matching, but in the above-mentioned conventional technique, the center of gravity of the recognition mark is obtained and the edge of the recognition mark is detected. However, when accuracy is required on the order of sub-μm as in the current situation, accurate positioning cannot be achieved. Further, as shown in FIG. 6b, even in the case of correlation, which is one method of pattern matching, the peak value indicating the matching degree is inevitably low. Further, the conventional technique has a problem that it is susceptible to noise due to the influence of illuminance and illumination form of light. Therefore, the present invention provides a position detection method capable of highly accurate positioning by performing pattern matching (correlation) between a recognition mark captured from a television camera and image data and a recognition mark serving as a reference stored in a computer. To do.

In order to achieve the above-mentioned object, the present invention provides a recognition mark in which an M-sequence, which is a signal, is two-dimensionally arranged at an intended position of an object, and the recognition mark is provided by a television camera. The image photographed and recognized in (1) and the previously stored recognition mark and the same reference mark are correlated using a matching method, and the position of the target object is detected based on the result.

In the above-mentioned position detecting method, by utilizing a new recognition work using a signal of M series, the characteristic that a sharp peak is shown at the most aligned position when pattern matching (correlation) is performed is utilized. , Sub μ
Positioning on the order of m is possible.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1a shows the M sequence (0101110
0010011) is converted into a two-dimensional array. When actually used, 1 is replaced with black and 0 is replaced with white. Further, FIG. 1b is a two-dimensional array of the signal M series shown in FIG. 1a, and FIG. 1c is an actually used recognition mark. 2a and 2b are examples in which the recognition mark shown in FIG. 1c is added to the wiring board and the semiconductor element. In FIG. 2a, 21 is a wiring board, 22 is wiring, 23 is an electrode, 24 is a recognition mark,
In FIG. 2b, 25 is a semiconductor element, 26 is an electrode, 2
Reference numeral 7 is a recognition mark. FIG. 3 shows an external view of equipment to which the position detecting method of the present invention is applied. In the figure, 31 is XY
A robot, 32 is a nozzle head for adsorbing semiconductor elements,
33 is a TV camera (top camera) for recognizing the wiring board, 34 is a TV camera (under camera) for recognizing the semiconductor element, 35 is a transport system, 36 is a wiring board, 37 is a semiconductor element, and 38 is parts It is a cassette.
Next, the operation of the above equipment will be described. Parts cassette 38
The suction nozzle head 32 picks up the semiconductor element 37 that has entered, and then the under camera 34 photographs the recognition mark of the semiconductor element 37 to which the recognition mark is given. After capturing the recognized image of the photographed mark, pattern matching (correlation) is performed with the regular recognition mark stored in advance in the computer to obtain the highest peak value as shown in FIG. On the other hand, the transport system 35 mechanically regulates the wiring substrate 36 having the recognition mark. afterwards,
The wiring board is photographed by the top camera 3. After capturing the recognized image of the photographed mark, pattern matching (correlation) with the regular recognition mark stored in advance in the computer is performed to obtain the highest peak value shown in FIG. Next, based on the positional information of the semiconductor element 37 and the wiring board 38 detected by the above method, as shown in FIG.
The correction value is transmitted to the (XY table) to correct the position, and then the semiconductor element 37 and the wiring board 36 are joined. In FIG. 5, reference numeral 52 is a television monitor that displays the image captured by the camera 33 and the image data recognized by the computer.

As described above, according to the present invention, by using a new recognition mark using a signal of M series, the influence of the illuminance of light and the incident angle of the light on the recognition mark, which have been problems in the past, can be eliminated. Moreover, by utilizing the feature that a sharp peak appears at the most aligned position when pattern matching (correlation) is performed, it has been impossible to achieve sub-μm until now.
Order positioning can be realized.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a recognition mark used in a position detection method of the present invention.

FIG. 2 is a diagram showing an example of a wiring board and a semiconductor element provided with a recognition mark.

FIG. 3 is an external view of equipment to which the position detection method of the present invention is applied.

FIG. 4 is an explanatory diagram of correlation peaks in pattern matching.

FIG. 5 is an explanatory diagram of the position correction of the wiring board.

FIG. 6 is an explanatory diagram of a conventional position detection method.

[Explanation of symbols]

 32 Nozzle head 33, 34 TV camera 36 Wiring board 37 Semiconductor element

Claims (1)

[Claims] 1. A recognition mark in which an M-sequence which is a signal is two-dimensionally arranged is provided at a position of an object, an image obtained by photographing the recognition mark with a television camera and the recognition mark and the recognition mark stored in advance. And a mark of the same reference are correlated using a matching method, and the position of the object is detected based on the correlation.