KR100497275B1 - Method for setting a location of a wafer transfer arm - Google Patents

Abstract

The present invention relates to a method for setting a moving position of a wafer transfer arm, wherein a hole having a large diameter is formed in a jig wafer, and once the light emitted from the sensor is irradiated into the hole, the jig wafer is subjected to a predetermined step. Detect the correct loading position.

According to the present invention, when the light emitted from the sensor is irradiated into the hole having a large diameter formed on the jig wafer, since the exact loading position of the jig wafer can be accurately detected, the horizontal movement position of the transfer arm can be easily set.

Description

METHOD FOR SETTING A LOCATION OF A WAFER TRANSFER ARM}

The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for setting the vertical position and the horizontal position of the transfer arm for transferring the wafer to a predetermined position.

In order to manufacture a semiconductor device, devices having appropriate electrical characteristics are formed on a wafer through a photo process, an etching process, a diffusion process, a deposition process, and a metal process, and the processed wafer is diced according to an assembly process, It goes through several processes, such as packaging.

The wafer is inevitably moved several times between these processes and is moved by the transfer arm to the supporter in the chamber where each process proceeds. For example, in a facility for performing a spin coater process, a wafer is moved by a transfer arm to a supporter in a plurality of units which respectively perform a process such as baking and coating, or a buffer unit for receiving a wafer between transfer arms. At this time, it is very important that the wafer is placed exactly at the center of the supporter. If the wafer is inaccurately placed in the bake unit or supporter in the application unit, a problem arises in that the entire surface of the wafer is not uniformly heated or uniform application of the photoresist occurs. In addition, if it is not correctly placed on the supporter of the buffer unit, the transfer arm unstablely holds the wafer, which causes problems such as the wafer falling off between transfers.

Therefore, in order to accurately position the wafer on the supporter, the transfer position of the transfer arm for placing the wafer on the support must be set before performing each process. Setting of the movement position of the transfer arm is made by manual operation by the operator or in the following manner. A sensor for irradiating light to the center of the position where the wafer is loaded is located on the upper part of the supporter, and a very fine hole (approximately 1 mm or less in diameter) is formed in the center of the jig wafer used for positioning the transfer arm. Thereafter, the transfer arm moves the jig wafer in a zigzag manner and finds a position where the light is introduced into the hole, and sets the position to the position of the transfer arm. However, this method is not only difficult to find the location because the hole is minute, but also takes a long time to find the location. In this way, the larger the diameter of the hole, the incorrect position of the wafer on the support.

It is an object of the present invention to provide a method for easily and accurately setting a moving position of a transfer arm so that a wafer can be accurately placed on a supporter.

In order to achieve the above object, the method of setting a transfer arm according to an embodiment of the present invention includes positioning a sensor unit for irradiating light to a loading position center of the wafer, wherein a jig wafer having a predetermined size hole is formed by the arm. Moving onto the supporter, setting the vertical movement position of the arm, and setting the horizontal movement position of the arm such that the center of the jig wafer is located at the loading position center.

The setting of the horizontal movement position of the arm may include moving the jig wafer in a predetermined direction so that the light is irradiated into the hole of the jig wafer, and the light is first irradiated into the hole. Detecting a first horizontal position and a second horizontal position of said arm from which said light deviates from said hole, and said arm moving said jig wafer about the center of said first horizontal position and said second horizontal position; Detecting a third horizontal position of the arm in which the arm moves the jig wafer in a direction perpendicular to a line segment connecting the first horizontal position and the second horizontal position and the light deviates from the hole; A fourth horizontal position of the arm in which the arm moves the jig wafer in a direction opposite to one direction and the light deviates from the hole And detecting a center of the third horizontal position and the fourth horizontal position as the horizontal movement position of the arm.

The setting of the vertical movement position of the arm may include detecting a reference position, which is a position of an arm having a maximum reflection amount, from the sensor unit, and adding or subtracting a predetermined distance from the reference position. And setting the movement position. In the detecting of the reference position, the arm moves the jig wafer in one of the up and down directions, and the first vertical direction of the arm at a moment when the reflection amount of the light reflected from the jig wafer is equal to a predetermined size of a predetermined reflection amount. Detecting a position, the arm moving the jig wafer in a direction opposite to one of the up and down directions, and when the amount of reflection of the light reflected from the jig wafer is equal to a predetermined size of the predetermined amount of reflection, Detecting a second vertical position, and setting a center of the first vertical position and the second vertical position as the reference position.

The hole formed in the jig wafer has a diameter of 5mm to 10mm. Alternatively, however, the holes may be formed to a suitable diameter depending on the system.

Hereinafter, an embodiment of the present invention will be described in more detail with reference to FIGS. 1 and 8. The embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Therefore, the shape of the elements in the drawings are exaggerated to emphasize a clearer description. In this embodiment, the transfer position of the transfer arm refers to the final position where the transfer arm is moved above the supporter to position the jig wafer (or wafer) on the lift pin when the lift pin protrudes from the supporter.

1 is a view schematically showing a part of a facility for performing a photo process. Referring to FIG. 1, baking units 100 for heating a wafer to a predetermined temperature are disposed at one side, and coating units 200 for coating a photoresist on the other side facing the baking unit 100. ) Is lined up. Between the baking unit 100 and the application unit 200, the transfer unit 300 is provided with a transfer arm 320 for transferring the wafer to these units (100, 200). In addition, a buffer unit 400 in which a wafer is placed is disposed between the transfer units 300 to exchange wafers between the transfer arms 320.

The transfer arm 320 is rotated about its own axis and linear movement in the vertical direction. In addition, the transfer arm 320 may be linearly moved in the left and right directions. The transfer arm 320 is positioned in the buffer unit 400 to move the wafer to the supporter 440 located in each unit 100 or 200 to perform a predetermined process or to exchange wafers between the transfer arms 320. The wafer is moved to the supported supporter 440. The supporter 440 may include a mechanical chuck having a mechanical finger, an electrostatic chuck that generates an electrostatic attraction between the wafer and the chuck according to a method of mounting the wafer, and a vacuum chuck that fixes the wafer by vacuum. Can be.

Holes, which are passages through which the lift pins 442 are moved up and down, are formed at the edge of the supporter 440, and the number may be three or more. That is, when the wafer is moved onto the supporter 440 by the transfer arm 320, the lift pins 442 are raised to support the wafer. The transfer arm 320 then returns to its original position after releasing the wafer, and the lift pins 442 are lowered while the wafer is mounted to the supporter 440 by electrostatic attraction or by vacuum. If the horizontal movement position of the transfer arm 320 that positions the wafer on the supporter 440 is set incorrectly, a predetermined process such as the wafer being unevenly heated or the photoresist is unevenly applied may not be performed uniformly on the wafer. Will not. If the horizontal movement position of the transfer arm 320 for holding the wafer positioned on the supporter 440 is set incorrectly, the supporter 440 is used in the buffer unit 400 for receiving the wafer between the transfer arms 320. It is not possible to correctly hold the wafer placed on the wafer and may drop the wafer during movement.

In addition, if the vertical movement position of the transfer arm 320 is set incorrectly, the lift pins 442, which are lifted up to support the wafer, may collide with the wafer. Therefore, the position of the transfer arm 320 is set using the jig wafer 20 before proceeding with the process. The jig wafer 20 is a wafer with a hole formed in the center, and may be a model using a general wafer or having the same conditions as a general wafer.

2 is a view schematically showing a configuration for setting the movement position of the transfer arm (320). Referring to FIG. 2, a supporter 440 on which a wafer is placed is positioned at a lower portion thereof, and a sensor 420 is installed at an upper portion thereof. Shown as an imaginary line in FIG. 2 shows the jig wafer 20 loaded at the correct position on the lift pin 442 protruding from the supporter 440. Hereinafter, the position of the jig wafer indicated by the pseudo line is called a loading position. The sensor 420 has a light emitting part for irradiating light to the center of the loading position and a light receiving part for receiving light reflected from the surface of the jig wafer 20. The sensor 420 preferably uses a sensor 420 capable of measuring the amount of reflection of the reflected light. The sensor 420 is connected to the control unit 500 that controls the movement of the transfer arm 320.

Next, a method of setting the moving position of the transfer arm 320 will be described with reference to FIGS. 4 to 8. 4 and 5 are views showing a method for setting the vertical movement position and the horizontal movement position of the transfer arm 320, respectively, and FIGS. 6 to 8 are the movement position, vertical movement position, respectively of the transfer arm 320, And it is a flowchart showing how to set the horizontal movement position sequentially.

First, light is irradiated from the sensor 420 to the center of the loading position (step S100). The transfer arm 320 moves the jig wafer 20 to the upper portion of the supporter 440 (step S200). Next, the transfer arm 320 is positioned. The positioning of the transfer arm 320 is largely divided into the vertical movement position setting and the horizontal movement position setting of the transfer arm 320, and the vertical movement position is first set (step S300).

3 is a diagram illustrating a relationship between the distance between the sensor 420 and the jig wafer 20 and the amount of reflection of light reflected from the jig wafer 20. In general, the amount of reflection varies according to the state of the jig wafer 20 and the surrounding environmental conditions, but the distance between the sensor 420 and the jig wafer 20 and the amount of light reflection have a shape as shown in the graph of FIG. 3. . In FIG. 3, the X axis represents the distance between the sensor 420 and the jig wafer 20, and the Y axis represents the reflection amount. That is, within the predetermined distance Q, the reflection amount increases as the jig wafer 20 moves away from the sensor 420, but when the jig wafer 20 moves away from the sensor 420, the reflection amount increases when the jig wafer 20 moves away from the sensor 420. Is reduced. As shown in FIG. 3, the relationship between the reflection amount and the distance is symmetric about the Q point.

In the present invention, the vertical position of the transfer arm 320 is preferably set such that the wafer is in contact with the lift pin 442 in a state in which the lift pin 442 protrudes above the supporter 440. In order to set the vertical position of the transfer arm 320 described above, first, the reference position (n in Fig. 4E) is detected (step S320). Here, the reference position represents a position spaced apart from the loading position (k in FIG. 4E) by a predetermined distance (Z). In this embodiment, the reference position is an amount of light reflected from the sensor hitting the jig wafer 20 and reflected. This is the maximum position. The predetermined distance is a distance preset according to the facility.

4 is a diagram illustrating detecting a reference position n of the transfer arm 320. Referring to FIG. 4, the transfer arm 320 initially moves the jig wafer 20 to the top of the supporter 440 (FIG. 4A). Since the transfer arm 320 is not in the correct position, the center of the jig wafer 20 does not coincide with the center of the above-described loading position. To set the vertical movement position of the transfer arm 320, the transfer arm 320 moves the jig wafer 20 downward (step S321). Light irradiated from the sensor hits the jig wafer 20 and is reflected, and the amount of reflection is continuously checked. When the amount of reflection has a predetermined size (P point in Fig. 3), the position is stored in the control part 500 at the first vertical position l of the transfer arm 320 (Fig. 4B, step S322). Thereafter, the transfer arm 320 moves the jig wafer 20 upward (step S323). The amount of reflection continues to increase, at which point it peaks and then decreases. When the amount of reflection has the predetermined size (P in Fig. 3), the position is stored in the control part 500 at the second vertical position m of the transfer arm 320 (Fig. 4C, step S324). The center n of the first vertical position l and the second vertical position m is set to the reference position (Fig. 4D, step S325). Thereafter, the position k moved by the predetermined distance Z from the reference position is set as the vertical movement position of the transfer arm 320 (Fig. 4E step S340).

In the above-described example, the first and second vertical positions are detected by moving the transfer arm downward first and then upwardly. Alternatively, the transfer arm may be moved first and then downward.

After setting the vertical movement position of the transfer arm 320, the horizontal movement position of the transfer arm 320 is set (step S400). The horizontal movement position is the position of the transfer arm 320 such that the center of the jig wafer 20 coincides with the center in the loaded state. 5 is a view showing setting the horizontal movement position of the transfer arm 320, x in Figure 5 represents the center of the loading position, and at the same time the position to which the light is irradiated.

Referring to FIG. 5, the transfer arm 320 moves the jig wafer 20 in a zigzag fashion so that the light from the sensor 420 is irradiated into the hole 22 formed in the jig wafer 20 (FIG. 5A, step). S410). Since the surface of the jig wafer 20 is made of a material capable of reflecting the light, the light irradiated to the surface of the jig wafer 20 is reflected, but the light irradiated to the hole formed in the jig wafer 20 is not reflected. The moment the light is irradiated into the hole 22, the position is stored in the control unit 500 as the first horizontal position 12 of the transfer arm 320 (FIG. 5B). The transfer arm 320 stores the position in the control unit 500 as the second horizontal position 13 of the transfer arm 320 as soon as the light deviates from the hole 22 while continuously moving the jig wafer 20 ( 5C, step S420). The transfer arm 320 moves the jig wafer 20 to the center 14 of the first horizontal position 12 and the second horizontal position 13 (FIG. 5D, step S430). Thereafter, the transfer arm 320 moves the jig wafer 20 in the direction perpendicular to the line segment connecting the first horizontal position 12 and the second horizontal position 13 (step S440). The moment the light deviates from the hole 22 during movement, the position is stored in the control part 500 as the 3rd horizontal position 15 (FIG. 5E, step S450). The transfer arm 320 moves the jig wafer 20 in the opposite direction (step S460), and at the moment when the light deviates from the hole 22, the transfer arm 320 stores the position in the control unit 500 as the fourth horizontal position 16. (FIG. 5F. Step S470). The center 17 of the third horizontal position 15 and the fourth horizontal position 16 is set to the horizontal moving position of the transfer arm 320 (Fig. 5G, step S480).

Thereafter, during the actual process, the transfer arm 320 transfers the wafer to the set moving position, and the wafer can be stably placed on the lift pin 442 and is exactly positioned at the center of the supporter 440 without being biased to one side. Can be.

The holes 22 formed in the jig wafer 20 are formed to be much larger than in the general case. If the diameter of the hole 22 is too small, it is difficult to detect the first horizontal position 12 of the transfer arm 320 initially. Preferably the diameter of the hole is preferably maintained from 5mm to 10mm.

According to this embodiment, since the hole formed in the jig wafer is much larger than in the general case, the first horizontal position can be easily detected, and then the horizontal moving position of the movable arm can be accurately set by mathematical calculation.

In the present embodiment, a description has been made with an example having a buffer unit for receiving a wafer between the coating unit 200, the baking unit 100, and the transfer arm 320, but in addition, the wafer is moved to a predetermined position such as a scrubber facility. It can be used for all installations using the transfer arm 320.

According to the present invention, when the light emitted from the sensor is irradiated into the hole having the large diameter formed on the jig wafer, the precise loading position of the jig wafer can be detected accurately, so that the horizontal movement position of the transfer arm can be easily set.

Further, according to the present invention, there is an effect that the vertical movement position of the transfer arm can be easily and easily detected.

In addition, according to the present invention, since the size of the hole formed in the jig wafer is very large as compared with the general case, the transfer arm has an effect that it is easy to find the position where the initial light is irradiated.

1 is a view showing a schematic configuration of a spin coater facility;

2 schematically illustrates an apparatus for positioning a wafer transfer arm of the present invention;

3 is a graph showing the relationship between the distance between the sensor and the jig wafer and the amount of light reflection;

4A to 4E show a procedure for setting the vertical movement position of the transfer arm;

5A to 5G show a procedure for setting the horizontal movement position of the transfer arm;

6 is a flowchart showing a sequence of setting the position of the transfer arm according to an embodiment of the present invention;

7 is a flowchart sequentially showing the order of setting the vertical position of the transfer arm according to an embodiment of the present invention; and

8 is a flowchart sequentially showing the order of setting the horizontal position of the transfer arm according to an embodiment of the present invention.

Explanation of symbols on main parts of the drawing

420: sensor 440: supporter

442: lift pin 500: control unit

320: transfer arm

Claims (7)

In the method for setting the position of the arm for moving the wafer to the supporter in a facility for manufacturing a semiconductor device, Positioning a sensor unit for irradiating light to a loading position center of the wafer; Moving the jig wafer having a circular hole in the center to the upper portion of the supporter by the arm; And Setting a horizontal movement position of the arm such that the center of the jig wafer is located at the loading position center, Setting the horizontal movement position of the arm, The arm moving the jig wafer; Detecting a first horizontal position of said arm at which said light is first irradiated into said hole and thereafter a second horizontal position of said arm at which said light deviates from said hole; The arm moving the jig wafer about the center of the first horizontal position and the second horizontal position; Detecting the third horizontal position of the arm in which the arm moves the jig wafer in one direction perpendicular to the line segment connecting the first horizontal position and the second horizontal position, and wherein the light deviates from the hole; Detecting a fourth horizontal position of the arm in which the arm moves the jig wafer in a direction opposite to the one direction, and wherein the light deviates from the hole; And And setting a center of the third horizontal position and the fourth horizontal position to a horizontal movement position of the arm. The method of claim 1, The method of setting the position of the wafer transfer arm further includes setting a vertical movement position of the arm prior to setting the horizontal movement position of the arm, Setting the vertical movement position of the arm, Detecting a reference position which is a position of an arm in which the amount of reflection of light from the sensor portion is maximum; And setting a position at which the predetermined distance is subtracted from the reference position as a vertical movement position of the arm. The method of claim 2, Detecting the reference position, The arm moving the jig wafer in one of vertical directions; Detecting a first vertical position of the arm at a moment when the reflection amount of the light reflected from the jig wafer is equal to a magnitude of a predetermined reflection amount; The arm moving the jig wafer in a direction opposite to one of the up and down directions; Detecting a second vertical position of the arm at a moment when the reflection amount of the light reflected from the jig wafer is equal to the predetermined reflection amount; and And setting a center of the first vertical position and the second vertical position as the reference position. The method according to claim 1 or 3, The hole is a positioning method of the wafer transfer arm, characterized in that formed to have a diameter of 5mm to 10mm. The method according to claim 1 or 3, And said equipment is a spinner equipment or a scrubber equipment. In the method for setting the position of the arm for moving the wafer to the supporter in a facility for manufacturing a semiconductor device, Positioning a sensor unit for irradiating light to a loading position center of the wafer; Moving a jig wafer over the supporter by the arm; And Setting a vertical movement position of the arm, Setting the vertical movement position of the arm, Detecting a reference position which is a position of an arm in which the amount of reflection of light is maximized from the sensor unit; And setting a position at which the predetermined distance is subtracted from the reference position as a vertical movement position of the arm. The method of claim 6, Detecting the reference position, The arm moving the jig wafer in one of vertical directions; Detecting a first vertical position of the arm at a moment when the reflection amount of the light reflected from the jig wafer is equal to a magnitude of a predetermined reflection amount; The arm moving the jig wafer in a direction opposite to one of the up and down directions; Detecting a second vertical position of the arm at a moment when the reflection amount of the light reflected from the jig wafer is equal to the predetermined reflection amount; and And setting a center of the first vertical position and the second vertical position as the reference position.