JPH038660Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Technical field to which the idea belongs]

This device is a wafer separation device that separates wafers one by one, which have a thickness of several hundred microns, are made of brittle materials, and have flat, smooth surfaces that tend to stick together when stacked. an advancing/retracting mechanism for advancing and retracting a plurality of stacked wafers in the stacking direction; and a suction pad disposed on a side opposite to the advancing/retracting mechanism of the stacked wafers and having a suction surface on the side opposite to the wafers. , moving the advancing/retracting mechanism forward to press the stacked wafers against the suction pad so that the wafers are attracted, then retracting the advancing/retracting mechanism, and separating the uppermost one of the pressed wafers by the suction pad; The present invention relates to a wafer separation device configured such that when the wafer is removed, the wafer that was in close contact with the separated wafer falls back to its original position.

[Prior art and its problems]

Semiconductor wafers, which are the subject of this invention, are thin, usually several hundred microns thick, are made of brittle material, and have smooth, flat surfaces that have been wrapped, so that when stacked, they do not stick together. It has an easy nature. Conventionally, the work of separating and taking out multiple wafers stacked one by one was done manually.In order to make this manual work easier, after wrapping the wafer surface, Efforts have been made to prevent wafers from coming into close contact by placing paper or the like between them. However, manual work was not only inefficient, but also risked damaging the thin and fragile wafers. Therefore, as a method to compensate for this drawback, a method has been proposed in which the separation operation is performed using a mechanical device, as described below, for example. FIG. 2 shows an example of the configuration of the main parts of this wafer separation apparatus. In this separating device, a plurality of wafers 6 are stacked in a stack in a magazine 4, with an air cylinder 3a as a movable part and an air piston 3b as a fixed part. By supplying air from an air source (not shown) to the advancing/retracting mechanism 3, the wafer is moved forward in the stacking direction. The wafer is pressed against the suction pad 1 having the suction surface Y that forms a gap δ larger than that of two wafers and is suctioned, and by shifting this suctioned wafer in the shearing direction as shown in FIG. It is configured to separate only wafers one by one. Here, 2 is a vacuum source to which the suction pad 1 is connected,
It operates when the wafer 6 is pressed against the suction pad 1 and serves to attract the wafer to the suction pad. Further, reference numeral 8 denotes a holding member that holds the suction pad 1 with a predetermined gap between it and the magazine 4 and moves it in the direction of shearing the wafer after suctioning the wafer. When the advancing/retracting mechanism 3 presses the wafer 6 against the suction pad 1 and then retreats to the original position, one or more wafers that come into close contact with the top wafer remain at the suction position, and return to the original position without coming into close contact. A gap h is formed between the returning wafer and the wafer that falls when the top wafer is separated and removed. This fall allowance ensures that when the top wafer adsorbed by the suction pad is shifted in the shearing direction, a force in the gravity direction is applied to the wafer that was in close contact with this wafer.
This is necessary to separate the top wafer without any damage by not applying any pressure to the wafer being separated, but this falling margin is too large and the falling wafer If the number of wafers is large, damage to the wafers is likely to occur. At the beginning of the wafer separation operation, the number of wafers in the magazine is large, so the chance of them falling is small, but as the separation process progresses, the number of wafers remaining in the magazine decreases, and therefore the chance of them falling is small. There was a problem in that the risk of damage to the wafers increased as the separation process progressed.

[Purpose of invention]

The object of this invention is to eliminate the above-mentioned drawbacks of the wafer separation apparatus, and to provide a wafer separation apparatus that is less likely to be damaged and can perform separation operations efficiently.

[Key points of the idea]

This invention includes an advancing/retracting mechanism for advancing and retracting a plurality of wafers stacked in a magazine in the stacking direction, and a suction surface disposed on the opposite side of the advancing/retracting mechanism of the stacked wafers and on the side opposite to the wafers. The advancing/retracting mechanism is moved forward to press the stacked wafers onto the suction pad so that the wafers are attracted, and then the advancing/retracting mechanism is moved back to remove the uppermost one of the pressed wafers. In the wafer separation device, the advancing/retracting mechanism is driven by a drive motor, and the wafer separating device is configured such that when a wafer is separated and removed by a suction pad, a wafer that was in close contact with the separated or removed wafer falls back to its original position. an elevating part capable of minutely controlling the amount of movement of the wafers in the stacking direction; one of a piston and a cylinder serves as a fixed part and is supported from the elevating part via an elastic member, and the other serves as a movable part, and a piston-cylinder device that moves forward and backward in the stacking direction of wafers, and supplies air to the piston-cylinder device so that a movable part of the device advances the wafer at high speed toward the suction pad, and the drive motor drives the elevating part. is moved forward and pressed against the suction pad, and this pressing position is determined by the relative displacement between the elevating portion and the fixed portion of the piston cylinder device when the elevating portion deforms the elastic member and moves further forward. wafers are detected, and the stop position of the elevating section is controlled to be a position moved forward or backward from the detection position in accordance with the number of wafers separated and removed by the suction pad. The aim is to maintain the constant constant and achieve the above objective.

[Example of idea]

FIG. 1 shows an embodiment of a wafer separation apparatus constructed based on the present invention. Inside the magazine 4 is a base plate 5.
A plurality of wafers 6 are stacked on top of the magazine, and a suction pad 1 connected to a vacuum source (not shown) is located on the upper open end side of the magazine, and its suction surface
The thickness of the wafer is 1 between
They are arranged so that a gap of more than one sheet is formed. A drive motor 1 is installed vertically below the magazine 4.
2 and a pinion rack (not shown), an elevating section 11 is provided which is driven in the vertical direction. I support it. Here, it is preferable that the drive motor 12 is, for example, a step motor so that the elevating section 11 can be moved in small steps in accordance with the thickness of the wafer. Here, the guide tube 16 is integrally connected to the elevating part 11 via a pin 17 at the lower part, and is connected to the piston 14 via a stop ring 18 in an intermediate position so that the piston 14 compresses the coil spring 9. axially movably coupled. Further, a sensor dog 7 is embedded in the piston 14 by passing through a long hole provided in the guide tube 16 in the radial direction.
and the sensor 10 fixed to the guide tube 16 changes in the axial direction, this change is detected by the sensor 10, and thereby the elevating section 1
1 and the piston 14 are detected. A cylinder 13 is arranged above the piston 14, and the upper end surface of the piston and the bottom surface of the cylinder are kept in contact with each other via a return spring 20.
When compressed air is sent from the air source 19 to the upper end of the piston through a hole provided in the axial center of the piston 14, the cylinder 13 compresses the return spring 20 through the cover 13a attached to the lower end surface of the cylinder 13, and returns the wafer 6. move forward towards. Hereinafter, the steps of the wafer separation operation starting from the supply of compressed air will be explained in detail. Now, the sum of the gap h 1 between the wafer 6 housed in the magazine 4 and the suction pad ₁ and the gap h ₂ between the base plate 5 and the cylinder 13 is the air source 1
Cylinder 1 with only compressed air supplied from 9
The amount of axial movement shall be greater than No. 3. Assuming this, it is not possible to press the wafer against the suction pad with compressed air alone, so current is continuously supplied to the drive motor 12 to control the lifting section 11.
is moved forward in the axial direction to press the wafer against the suction pad. When the uppermost wafer adsorbed by the adsorption pad is separated and removed, for example, by the method shown in FIGS. 2 and 3, the compressed air sent into the cylinder 13 is exhausted to the outside,
3, due to the force of the return spring 20, the bottom surface of the piston 1
Retreat to a position where it makes contact with 4. This retreat amount is
It is equal to the sum of the gaps h ₁ and h ₂ minus the amount of advance of the elevating section. Furthermore, the gap _h2 at this time also becomes smaller than the value before the cylinder 13 operates by the amount of advance of the elevating section. As the wafer separation operation progresses, the gap h ₁ increases, and therefore, the fall margin of the wafers that were in close contact with the separated and removed wafers also increases.
If the falling allowance becomes too large, the wafer is likely to be damaged, so it is necessary to advance the return position of the cylinder 13 to maintain the falling allowance at an appropriate value. This proper return position is usually determined at the beginning of separation work.
It is located at a position where h ₂ > 0, and in the latter half, h ₂ < 0
That is, the base plate 5 is in a lifted position into the magazine 4. The procedure for determining the amount of advance of the elevating section to provide this appropriate return position is as follows. First, compressed air is fed into the cylinder 13 from the air source 8 to move the cylinder 13 forward by its full possible travel distance. Next, current is supplied to the drive motor to move the elevating section 11 forward and press the wafer 6 against the suction pad 1. The elevating section 11 tries to move forward further, but since neither the cylinder 13 nor the piston 14 can move anymore, the elevating section 11
only moves forward while compressing the coil spring 9. A sensor 10 is provided on the guide cylinder 16 that is integrally connected to the elevating part 11, and a sensor dog 17 is installed on the piston 14 side so as to face this sensor. When only the portion 11 moves forward, the sensor 10 and the sensor dog 17
The distance between the two changes. Sensor 10 detects this change.
When the wafer 6 is detected, the wafer 6 is moved to the suction pad 1.
The upper end surface Z of the cylinder 13 when pressed against
can detect the position of Since the total possible movement amount of the cylinder 13 with respect to the piston 14 is constant, when this movement amount is larger than the proper fall margin of the wafer, the elevating section 11 is further advanced from the detection position, and the air is exhausted and the cylinder 13
The amount of retreat when the wafer retreats, that is, the fall margin of the wafer, is taken as an appropriate value. Further, when the total possible movement amount of the cylinder is smaller than the proper wafer falling margin, the elevating section is moved back from the detection position, and the amount of retreat when the cylinder 13 is retreated after air is exhausted, that is, the wafer falling distance is reduced. is the appropriate value. Therefore, if the separation device is configured so that the total possible movement distance of the cylinder 13 relative to the piston 14 is larger than the proper fall distance of the wafer, the elevating and lowering part can be used only when separating the first wafer at the start of the separation operation. It takes some time for the cylinder 11 to come to the proper stop position, but from the second image onwards, the sensor 10 will be inactive and the air will be in and out of the cylinder 13.
By advancing the elevating section 11 by one wafer thickness each time, the wafers can be separated and taken out one by one at high speed and without damage. In addition, if the separation device is configured such that the total possible movement distance of the cylinder 13 relative to the piston 14 is smaller than the proper fall distance of the wafer, the elevating section
It takes some time for cylinder 13 to reach the proper stopping position, but from the second cylinder onwards, the amount of movement of the lifting section 11 is minimal, so by bringing the total possible movement of cylinder 13 closer to the appropriate falling position, High-speed separation of wafers becomes possible. If the wafer separation operation were to be carried out using only the elevating section 11 without using the piston-cylinder device comprising the cylinder 13, piston 14, and return spring 20, damage to the wafers could be avoided, but High-speed separation, which is one of the purposes of wafer separation using mechanical equipment, is difficult.

[Effect of the idea]

As described above, according to the present invention, when the uppermost wafer is attracted by the suction pad and separated and removed, the wafer separating device equipped with the suction pad Alternatively, in order to ensure that the fall margin when multiple wafers fall is an appropriate value with as little error as possible, it is constructed using an elevating section that allows for minute control of the amount of advancement and retraction that corresponds to the thickness of the wafers. The function of optimizing the drop margin and the function of advancing the wafer toward the suction pad at high speed are achieved by an elevating section whose advance and retreat are minutely controlled by a drive motor, and a piston cylinder device operated by air pressure. Since they are assigned to each part, damage to the wafer during separation work is significantly less likely to occur, and the wafer separation work can be performed at high speed.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a wafer separation device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of main parts showing the configuration of a conventional wafer separation device, and FIG. FIG. 2 is an explanatory diagram showing a separation method. 1: Adsorption pad, 3: Forward/backward mechanism, 4: Magazine, 6: Wafer, 7: Sensor dog, 9: Coil spring, 10: Sensor, 11: Lifting section, 12: Drive motor, 13: Cylinder, 14: Piston, 1
9: Air source.

Claims (1)

[Claims for Utility Model Registration] An advancing/retracting mechanism for advancing and retracting a plurality of wafers stacked in a magazine in the stacking direction; a suction pad having a suction surface, the advance/retreat mechanism is moved forward to press the stacked wafers onto the suction pad so that the wafers are attracted, and then the advance/retreat mechanism is retreated to remove the topmost of the pressed wafers. When the upper one is separated and removed by the suction pad, the separation,
In a wafer separation device configured such that the removed wafer and the wafers that were in close contact with each other fall back to their original positions, the advancing/retracting mechanism is driven by a drive motor to move the wafers back and forth by a minute amount in the stacking direction. A controllable elevating section; and a piston-cylinder device in which either the piston or the cylinder serves as a fixed section and is supported from the elevating section via an elastic member, and the other is a movable section that moves forward and backward in the wafer stacking direction using air pressure. supplying air to the piston-cylinder device, the movable part of the device advances the wafer at high speed toward the suction pad, and the driving motor causes the elevating part to follow and advance to press the wafer against the suction pad. , the pressing position is detected from the relative displacement between the elevating portion and the fixed portion of the piston cylinder device when the elevating portion deforms the elastic member and moves further forward, and the stopping position of the elevating portion is detected. . A wafer separation apparatus, characterized in that the wafer separation apparatus is controlled to move forward or backward from the detection position in accordance with the number of wafers separated and removed by the suction pad.