JP2005186134A - Method for initial setting of laser trimming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a necessity of mechanical adjustment for a XY stage by utilizing pattern recognition in an initial setting of a laser trimming apparatus. <P>SOLUTION: A rotation angle θ1 required to set a reference axis on a coordinate system of a beam positioner parallel to X-axis of XY stage, a rotation angle θ2 required to set the reference axis of a work table parallel to X-axis of XY stage, and an angle θ3 which is made by intersection of X-axis of XY stage with a straight line joining two measuring terminals of a probe are obtained by using pattern recognition. By turning the work table by θ3-θ2 while turning the reference axis on the coordinate system of the beam positioner by θ3-θ1, the reference axis of the work table, the reference axis on the coordinate system of the beam positioner and the straight line joining the two measuring terminals of the probe are made parallel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an initial setting method for aligning components in a laser trimming apparatus for trimming the line width and the like of a resistance element of a semiconductor chip.

  In the laser trimming device, the position of the semiconductor chip resistor substrate is not only determined by mechanical alignment of the XY stage, but also the arrangement of the resistors on the substrate to be trimmed is recognized by the camera, and the laser position is controlled based on this. Technology (Patent Document 1: Japanese Patent Laid-Open No. 61-067904), a technique for comparing a pattern on a substrate to be trimmed with a pattern at a predetermined trimming start position, and determining a trimming start position according to the comparison result (Patent Document 2) : JP-A-63-16885), two positioning marks are provided in advance on an IC substrate, the marks are imaged, and a positional deviation amount is obtained by pattern recognition in comparison with a normal position stored in advance. A technique for correcting and controlling the amount of deviation by separately calculating the amount of deviation in the X and Y directions and the amount of deviation in the θ direction (Patent Document 3: Japanese Patent Laid-Open No. Hei 2). 147182), the necessary correction amount for each mounting table is stored, the position of the probe is finely adjusted for each mounting table, and a pattern recognition unit is combined to generate for each substrate of the workpiece. A technique (Patent Document 4: Japanese Patent Laid-Open No. 5-293680) that can correct a dimensional error and a printing deviation of a substrate that has been proposed has been proposed. A technique for correcting the position of the workpiece, the position of the probe, and the position of the laser using pattern recognition is also actually used, which contributes to the improvement of productivity in the laser trimming process.

JP 61-0697904 JP 63-16885 A JP-A-2-147182 JP-A-5-293680

  However, in the initial setting of the laser trimming apparatus, the time required for the initial setting varies greatly depending on the skill level of the operator, and it cannot be said that the productivity of the laser trimming apparatus is high. In addition, the adjustment time when the beam positioner, which is a consumable item, is replaced also greatly depends on the skill level of the operator.

  The present invention has been made in view of such problems, and an object of the present invention is to provide an initial setting method for a laser trimming apparatus that can reduce initial setting work of the laser trimming apparatus and can perform initial setting in a short time. And

The initial setting method of the laser trimming apparatus according to the present invention is to measure the characteristics of the workpiece placed on the stage on the XY stage with a probe and use a beam positioner so that the measured value becomes a predetermined value. In an initial setting method of a laser trimming apparatus that performs laser trimming by controlling an irradiation position of a laser beam,
Forming two marks on the table with the laser beam controlled by the beam positioner;
Obtaining a rotation angle θ1 of the beam positioner necessary to make the reference axis of the coordinate system of the beam positioner parallel to a predetermined reference axis Z by photographing the mark and recognizing a pattern;
A step of obtaining a rotation angle θ2 of the mounting table necessary for making the reference axis of the mounting table parallel to the reference axis Z by photographing a portion to be a reference axis of the mounting table and recognizing a pattern; ,
Obtaining a rotation angle θ3 of the probe necessary for making the reference axis of the probe parallel to the reference axis Z by capturing a pattern and recognizing a pattern as a reference axis of the probe;
By adjusting the beam positioner, the object table, and the probe so that the values of the θ1, θ2, and θ3 are the same, the reference axis of the coordinate system of the beam positioner, the reference axis of the object table, and the And a step of making the reference axis of the probe parallel.

  The inventor of the present invention is that the cause of the above-mentioned problem is that the alignment of the optical system is mechanically performed by mechanically adjusting the parallel and right-angle accuracy of the XY stage, that is, the alignment of the optical system is mechanically performed. As a result of studying a method that eliminates the need for mechanical alignment, the present invention has been achieved. In other words, if pattern recognition is utilized during the initial setting of the laser trimming apparatus as in the present invention, mechanical adjustment of the XY stage can be eliminated during the initial setting, and the time required for the initial setting can be reduced. It can be greatly shortened. In addition, the adjustment time when the beam positioner, which is a consumable item, is replaced can be shortened.

  The reference axis Z may be set to the X axis of the XY stage.

  The reference axis of the measurement probe may be set to a straight line connecting the two measurement terminals of the probe.

  Further, the step of making the reference axis of the coordinate system of the beam positioner, the reference axis of the object table and the reference axis of the probe parallel to each other is based on θ1, θ2, and θ3, and the reference axis of the coordinate system of the beam positioner Is rotated by θ3−θ1 and the above described table is rotated by θ3−θ2, so that the above described table, the reference axis of the coordinate system of the beam positioner, and the probe are adjusted so that the above θ1 to θ3 are the same. You may adjust. By adjusting in this way, even if the probe does not rotate, the reference axis of the object table, the reference axis of the coordinate system of the beam positioner, and the straight line connecting the two measurement terminals of the probe are made parallel. Can do.

  The initial setting method of the present invention can also be used for initial setting performed when the beam positioner is replaced.

  Note that the rotation angle of the stage required to be parallel to the X axis of the XY stage and the angle between the straight line connecting the two measurement terminals of the probe and the X axis of the XY stage are determined from the mechanical positional relationship. Although it is an angle, the rotation angle obtained for the beam positioner is a rotation angle necessary for making the reference axis of the coordinate system of the beam positioner parallel to the X axis of the XY stage on the software.

  In the method according to the present invention, since pattern recognition is utilized at the initial setting of the laser trimming apparatus, mechanical adjustment of the XY stage can be made unnecessary at the initial setting, which is necessary for the initial setting. Time can be greatly reduced. In addition, the adjustment time when the beam positioner, which is a consumable item, is replaced can be shortened.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings.

  FIG. 1 is a diagram showing an overall configuration of a laser trimming apparatus that performs an initial setting method according to an embodiment of the present invention. When the stage 2 is installed on the XY stage 1 and the laser trimming process is performed, a workpiece (not shown) to be measured is installed on the stage 2. The location serving as the reference axis of the mounting table 2 is two positioning marks attached to the master substrate 3 installed on the mounting table in the initial setting. Above the mounting table 2, a probe 4 and a beam positioner 5 for measuring characteristics of the workpiece are disposed, and a camera 6 used for pattern recognition is disposed further above. Data based on the image photographed by the camera 6 is processed by the pattern recognition processing unit 7. Control of the position of the XY stage 1 and processing of signals from the probe 4 when performing laser trimming processing are performed by the arithmetic control unit 8.

  Next, an initial setting method of the laser trimming apparatus according to the present embodiment will be described in the order of steps with reference to FIGS.

  First, as shown in FIG. 2, a laser beam is irradiated onto the mounting table by a beam positioner to form cross cuts as marks at two positions on the mounting table. Next, as shown in FIG. 3, the XY stage is moved to place the two cross cuts in the center of the shooting area of the camera, and the two cross cuts are shot with the camera. An image photographed by the camera is input to the pattern recognition processing unit 7 of the computer, subjected to image processing, pattern recognition is performed, and the position and direction of the cross cut are recognized. Based on this result, the calculation control unit 8 determines the rotation angle θ1 necessary for making the reference axis of the coordinate system of the beam positioner parallel to the X axis of the XY stage on the software. FIG. 4 shows a case where the rotation angle θ1 required for making the reference axis of the coordinate system of the beam positioner parallel to the X axis of the XY stage is rotated on the software based on the rotation angle θ1 obtained by this pattern recognition. It is a schematic diagram which shows the positional relationship of an XY stage, a mounting base, and a beam positioner.

  Next, as shown in FIG. 5, the master substrate 3 is set on the stage 2, and then the XY stage 1 is moved so that the two positioning marks attached to the master substrate 3 are respectively set at the centers of the photographing areas of the camera. The two positioning marks on the master board are photographed with a camera. The master substrate 3 to which the two positioning marks are attached is a substrate used only for positioning the mounting table 2. An image photographed by the camera is input to the pattern recognition processing unit 7 of the computer, subjected to image processing, pattern recognition is performed, and the positions and directions of the two positioning marks attached to the master substrate are recognized. Based on this result, the rotation angle θ2 required to make the reference axis of the stage table parallel to the X axis of the XY stage is obtained. FIG. 6 shows a case where the stage is rotated by the rotational angle θ2 necessary for making the reference axis of the stage 2 parallel to the X axis of the XY stage based on the rotation angle θ2 obtained by the pattern recognition. It is a schematic diagram which shows the positional relationship of an XY stage, a mounting base, a master substrate, and a beam positioner.

  Next, pattern recognition is performed on the two measurement terminals of the probe. In this embodiment, the probe is fixed, and the probe does not move in conjunction with the movement of the XY stage. Therefore, the positions of the two measurement terminals of the probe cannot be determined in the coordinate system of the XY stage. Therefore, in pattern recognition of the two measurement terminals of the probe, the direction of the mirror of the beam positioner is adjusted so that the beam hits the two measurement terminals of the probe, and the two measurement terminals of the probe are photographed with a camera. The positions of the two measurement terminals of the probe are determined in the coordinate system of the beam positioner.

  FIG. 7 is a schematic diagram of a process of photographing two measurement terminals of the probe with a camera and obtaining an angle θ3 formed by a straight line connecting the two measurement terminals of the probe and the X axis of the XY stage based on pattern recognition. is there. An image photographed by the camera is input to the pattern recognition processing unit 7 of the computer, subjected to image processing, pattern recognition, and the positions and directions of the two measurement terminals of the probe are recognized. Based on this result, an angle θ3 formed by the straight line connecting the two measurement terminals of the probe and the X axis of the XY stage is obtained. When the reference axis of the beam positioner's coordinate system is rotated by θ3-θ1, and the stage is rotated by θ3-θ2, a straight line connecting the reference axis of the beam positioner's coordinate system and the two measurement terminals of the probe, The base axis of the pedestal is parallel. By setting in this state, the initial setting of the laser trimming apparatus is completed. Fig. 8 shows the measurement of the reference axis of the beam positioner's coordinate system and the probe by rotating the reference axis of the coordinate system of the beam positioner by θ3-θ1 on the software and rotating the stage by θ3-θ2. FIG. 5 is a schematic diagram showing a state in which initial setting is completed in a state in which a straight line connecting terminals and a reference axis of a mounting table are parallel to each other.

  When performing laser trimming using this laser trimming apparatus, the XY stage moves so that the laser hits a predetermined position of the object. The movement of the XY stage is based on the calculation result by the computer. In the calculation, the position is corrected by the values of the rotation angles θ3−θ1 and θ3−θ2 obtained in the initial setting.

  Laser light from a laser generator (not shown) is reflected by a reflecting mirror in the beam positioner 5, and the laser light is irradiated to a predetermined position of the workpiece, and laser trimming processing is performed. A signal with respect to the resistance value from the probe 4 is sent to the arithmetic control unit 8, and when the signal reaches a predetermined value, the arithmetic control unit 8 gives a signal to a laser generator (not shown), and laser light Stop the occurrence of

  The present invention significantly reduces the initial setting work in a laser trimming apparatus for trimming a resistance element of a semiconductor chip.

It is a figure which shows the whole structure of the laser trimming apparatus which enforces the initial setting method which concerns on this invention. It is a schematic diagram of the process of forming a cross cut as a mark at two positions on the mounting table with a beam positioner. It is a schematic diagram of the process which image | photographs the said two cross cuts with a camera. FIG. 5 is a schematic diagram when the reference axis of the coordinate system of the beam positioner is rotated on software by a rotation angle θ1 required to be parallel to the X axis of the XY stage. It is a schematic diagram of a process of photographing the two positioning marks with a camera after mounting the master substrate with two positioning marks on the stage. It is a schematic diagram when the stage is rotated by a rotation angle θ2 necessary for making the reference axis of the stage parallel to the X axis of the XY stage. It is a schematic diagram of a process of photographing two measurement terminals of the probe with a camera and obtaining an angle θ3 formed by a straight line connecting the two measurement terminals of the probe and the X axis of the XY stage based on pattern recognition. The reference axis of the coordinate system of the beam positioner is rotated by θ3−θ1 on the software, and the stage is rotated by θ3−θ2, and the reference axis of the coordinate system of the beam positioner and the two measurement terminals of the probe are connected. It is a schematic diagram which shows the state which the initial setting was completed in the state which the reference axis of the straight line and the mounting base became parallel.

Explanation of symbols

1: XY stage 2: Mounting table 3: Master substrate 4: Probe 5: Beam positioner 6: Camera 7: Pattern recognition processing unit 8: Calculation control unit 9: Cross cut 10: Marker on the master substrate

Claims (5)

The characteristics of the workpiece placed on the stage on the XY stage are measured with a probe, and laser trimming is performed by controlling the irradiation position of the laser beam with a beam positioner so that the measured value becomes a predetermined value. In the initial setting method of the laser trimming apparatus,
Forming two marks on the table with the laser beam controlled by the beam positioner;
Obtaining a rotation angle θ1 of the beam positioner necessary to make the reference axis of the coordinate system of the beam positioner parallel to a predetermined reference axis Z by photographing the mark and recognizing a pattern;
A step of obtaining a rotation angle θ2 of the mounting table necessary for making the reference axis of the mounting table parallel to the reference axis Z by photographing a portion to be a reference axis of the mounting table and recognizing a pattern; ,
Obtaining a rotation angle θ3 of the probe necessary for making the reference axis of the probe parallel to the reference axis Z by capturing a pattern and recognizing a pattern as a reference axis of the probe;
By adjusting the beam positioner, the object table, and the probe so that the values of the θ1, θ2, and θ3 are the same, the reference axis of the coordinate system of the beam positioner, the reference axis of the object table, and the An initial setting method for a laser trimming apparatus, comprising: a step of making a reference axis of a probe parallel.   2. The laser trimming apparatus initial setting method according to claim 1, wherein the reference axis Z is set to an X axis of an XY stage.   3. The laser trimming apparatus initial setting method according to claim 1, wherein the reference axis of the probe is set to a straight line connecting two measurement terminals of the probe.   The step of making the reference axis of the coordinate system of the beam positioner, the reference axis of the object table and the reference axis of the probe parallel to each other is based on θ1, θ2, and θ3, and the reference axis of the coordinate system of the beam positioner is θ3. By rotating by −θ1 and rotating the above-described object table by θ3−θ2, the object table, the reference axis of the coordinate system of the beam positioner, and the probe are adjusted so that the θ1 to θ3 are the same. 4. The laser trimming apparatus initial setting method according to claim 1, wherein the laser trimming apparatus is an initial setting method.   5. The laser trimming apparatus initial setting method according to claim 1, wherein the initial setting method is performed when the beam positioner is replaced. 6.

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