JP4849482B2 - Underwater aligner for semiconductor wafers with notches - Google Patents

Description

  The present invention relates to an aligning device for orienting a semiconductor wafer provided with a notch so that the notch is oriented in a predetermined direction, and more particularly to an underwater aligning device capable of performing aligning in immersion water.

  A semiconductor wafer is obtained by slicing a cylindrical semiconductor ingot. A flat part on the front side on which a pattern is formed, a flat part on the back side thereof, a bevel surface formed on the front and back sides of the peripheral part, and between the bevel surfaces. It has a cylindrical surface. A cutout, a so-called notch, is formed at one portion of this peripheral portion, and the surface (notch surface) on which this notch is formed is subjected to mirror polishing similarly to the other surfaces.

  The semiconductor wafer is substantially disk-shaped, and the above surfaces are basically the same with respect to the center line of the wafer. Therefore, it is possible to polish without considering the direction of the semiconductor wafer. However, since only the notch and the notch surface do not have the above equivalence, in order to polish the notch, the notch and the notch surface of the semiconductor wafer must be oriented so as to face the polishing tool.

  For this orientation, a wafer aligning device is provided in the semiconductor wafer manufacturing apparatus, and an aligning operation for directing the notch in a predetermined direction is performed before the semiconductor wafer is carried into the notch polishing device by the transfer device. Is called. Conventionally, a wafer aligning device places a semiconductor wafer horizontally, rotates it around a vertical central axis, and stops rotation when the notch reaches a predetermined angular position. This is a configuration that is usually adopted. Examples of the wafer aligning apparatus having such a configuration can be found in Patent Documents 1 to 6.

  On the other hand, in semiconductor manufacturing, external factors such as contamination due to adhesion of particles and chemical contamination are most disliked as those that lower the yield and impair the reliability of products. Therefore, cleaning of the semiconductor wafer is repeatedly performed in the process. In addition, particles once adhered to the semiconductor wafer adhere more firmly by drying, and may be difficult to remove by cleaning, and problems such as formation of an unplanned oxide film due to contact with air by drying. Therefore, exposure to air is avoided as much as possible.

  For this reason, while waiting for processing of the next process, a countermeasure such as storage in water, or as disclosed in, for example, Patent Documents 7 and 8, when transporting a semiconductor wafer, pure water is supplied. Technology is also known that does this while wetting the surface.

JP 05-218179 A JP-A-11-040652 JP 2003-053645 A JP 2003-077872 A JP 2003-188235 A Japanese Utility Model Publication No. 03-116039 Japanese Patent Laid-Open No. 06-326067 Japanese Patent Laid-Open No. 07-074133

  As described above, the general problem of preventing drying of a semiconductor wafer in the semiconductor manufacturing process or preventing the semiconductor wafer from being exposed to air as much as possible is known in the art. Rather than just addressing this general problem, aligning the semiconductor wafers in water, ensuring that there is no air contact during the alignment, and aligning In order to perform underwater, the present invention is intended to solve even problems that do not occur at all in the conventional aligning work in air, or unique matters that are not considered as problems.

  The above problem is solved by the following means. That is, the first invention is an immersion water tank provided with an inlet for allowing immersion water to flow in and an outlet for allowing the immersion water to flow out from the vicinity of the water surface when the injected immersion water exceeds a predetermined water level. A plurality of support rollers that support and rotate a semiconductor wafer having a notch in immersion water in a water tank, a drive belt that rotates the support roller, a belt drive device that drives the drive belt, and a peripheral edge of the semiconductor wafer When the notch formed on the peripheral edge rotates to this position, the optical notch sensor that optically detects this and the bubbles blocking the optical path of the optical notch sensor are removed. An air bubble removing device, a mechanical notch engaging device, an engaging claw mechanically engageable with the notch, and the engaging claw toward a peripheral edge of the semiconductor wafer An engaging claw urging device capable of urging and capable of switching between an urging state and an urging release state, and detecting when the engaging claw is engaged with the notch A mechanical notch engagement device provided with an engagement sensor, a transfer device for carrying the semiconductor wafer into and out of a support position by the support roller, and a control device, wherein the semiconductor wafer supported by the support roller When the optical notch sensor detects the notch, the engaging claw urging device is switched to the urging state, and the engaging claw is engaged with the notch by further rotation of the semiconductor wafer. An underwater aligner for a semiconductor wafer having a notch, comprising: a control device that controls the belt drive device to stop when the engagement sensor is detected by the engagement sensor. It is a packaging apparatus.

  According to a second aspect of the present invention, there is provided an underwater aligning device for a semiconductor wafer having a notch according to the first aspect, wherein the bubble removing device is configured to eject water toward an optical path of the optical notch sensor. An underwater aligning device for a semiconductor wafer having a notch, characterized by comprising a nozzle.

  A third invention is an underwater aligning device for a semiconductor wafer having a notch according to the second invention, wherein the optical notch sensor is coupled to a light emitting / receiving device having one end installed outside the immersion water tank. An underwater aligning device for a semiconductor wafer having a notch, comprising a pair of optical fiber sensors arranged so that the other ends face each other and the peripheral edge of the semiconductor wafer is desired.

  According to a fourth aspect of the present invention, in the underwater aligning device for a semiconductor wafer having a notch according to the third aspect of the invention, when the control device switches the engagement claw biasing device to a biased state, An underwater aligning device for a semiconductor wafer having a notch, wherein the rotation speed of the semiconductor wafer can be switched from a first speed to a second speed lower than the first speed.

  A fifth invention is an underwater aligning device for a semiconductor wafer having a notch according to the fourth invention, wherein the engaging claws have the same cross-sectional contour shape along the rotation axis direction of the semiconductor wafer. And an underwater aligning device for a semiconductor wafer having a notch, wherein the contact position with the notch can be changed along this direction.

  A sixth aspect of the invention is an underwater aligning device for a semiconductor wafer having a notch according to the fifth aspect of the invention, wherein a part of the plurality of support rollers is placed on a transport path of the semiconductor wafer. When the transport device transports the semiconductor wafer, the transport device is temporarily retracted from the transport path to a retracted position so that the semiconductor wafer is not subjected to large immersion water resistance in the front direction. An underwater aligning device for a semiconductor wafer provided with a notch, characterized in that it can be conveyed along its flat surface.

  A seventh invention is an underwater aligner for a semiconductor wafer having a notch according to the sixth invention, wherein the support roller supports the semiconductor wafer in a state in which the flat surface is substantially vertical. An underwater aligning device for a semiconductor wafer provided with a notch, characterized in that:

  According to the underwater aligning apparatus for a semiconductor wafer having a notch according to the present invention, the semiconductor wafer is in the immersion water during the aligning operation, and does not come into contact with air at all. Since contamination and chemical contamination due to oxygen in the air can be prevented, factors that lower the yield and product reliability in the semiconductor manufacturing process can be reduced.

  In the present invention, an optical notch sensor is used for notch detection. However, since it is underwater, bubbles may adhere to the notch surface of the semiconductor wafer or the optical surface of the notch sensor, blocking the optical path, which may hinder the reliability of notch detection.

  In other words, when the transport device transports the semiconductor wafer in the outside air through the water surface into the immersion water, bubbles are embraced in the recess of the notch and the semiconductor wafer is supported in the aligning position without dropping. It is considered that this occurs when air bubbles drifting in the immersion water adhere to the optical or notch surface of the notch sensor for some reason.

  In the present invention, an air bubble removing device is provided, and by removing these adhering air bubbles, this particular problem caused by aligning being performed in immersion water is solved. This is one of the features of the present invention. The bubble removing device can be embodied by a configuration in which water is ejected from the nozzle toward the optical path of the optical notch sensor.

  The optical notch sensor uses a pair of optical fiber sensors, one end of which is coupled to a light emitting / receiving device installed outside the immersion water tank, and the other end faces each other so that the peripheral portion of the semiconductor wafer is desired. Has been. Since the light emitting and receiving device is installed outside that is not easily affected by immersion water, measures such as electrical insulation and maintenance are easier and troubles are reduced compared to installing the entire optical notch sensor in water. Can do.

  In the present invention, at the time of aligning, the semiconductor wafer is supported and rotated by the support roller, and this support roller itself employs a drive system using a drive belt. This is because it is simple and has the fewest troubles underwater. However, since the driving belt uses rubber to give flexibility, it is inevitable that the driving belt is stretched to some extent when the driving force is transmitted.

  Therefore, when the notch position is detected by the optical notch sensor alone and the rotation of the semiconductor wafer is stopped, the semiconductor wafer undergoes slight rotation due to the slow contraction of the drive belt after the aligning operation. Arise. In the present invention, a notch engaging claw is inserted into the notch at the end of the aligning operation, and this mechanical engagement prevents unintentional rotation due to the contraction. The combination of notch detection by the optical notch sensor and mechanical engagement to the notch by the engaging claw is one of the features of the present invention.

  It is advantageous from the viewpoint of aligning time to rotate the semiconductor wafer as fast as possible at the time of notch detection. However, on the other hand, since the engagement of the notch engaging claws is mechanical, if it is too fast, an impact may occur at the time of engagement and the notch surface may be damaged. For this reason, it cannot be made very fast. In the present invention, when the engaging claw urging device is switched to the urging state, the rotation speed of the semiconductor wafer can be controlled to be switched from the first speed to the second speed lower than this.

  Accordingly, in the present invention, the semiconductor wafer is moved at the first high speed until the optical notch sensor detects the notch, and at the second low speed until the notch engaging claw engages with the notch after this detection. Will rotate. Thereby, the aligning time can be shortened without damaging the notch surface.

  The engaging claw wears out as it repeatedly engages with the notch, and the positioning accuracy decreases. In the present invention, the engaging claws have the same cross-sectional contour shape along the rotation axis direction of the semiconductor wafer. As a result of using at the same contact position for a long period of time, wear occurs and accuracy cannot be secured, or before that, the contact position with the above notch can be moved along the above direction to change the contact position It is.

  In the present invention, the semiconductor wafer is aligned by being supported by the support roller in a state where the flat surface is substantially vertical. For example, when the transport device transports the semiconductor wafer from the outside to the support position by the support roller and from the support position to the outside, for example, at least a part of the semiconductor wafer is in immersion water. While the resistance influences the conveyance, the semiconductor wafer is moved in a direction so as to be along the flat surface of the semiconductor wafer as much as possible for the following reason.

  The transfer is usually performed by using three or four grip pins of the hand and pressing the grip pins from around the cylindrical surface between the upper and lower bevel surfaces of the semiconductor wafer. For this reason, a contact part will be in the state which cylindrical surfaces contact | connect on the outer side, and a contact area will decrease very much. Therefore, a very local force is applied to the contact portion. For this reason, coupled with the fact that the semiconductor wafer is thin and brittle, it cannot be gripped with a strong force.

  In the present invention, the posture in which the semiconductor wafer is supported and the direction in which the semiconductor wafer is conveyed are in substantially the same plane, and substantially includes movement in the direction perpendicular to the surface while the semiconductor wafer is conveyed in the immersion water. Absent. For this reason, the resistance of immersion water can be minimized. As a result, the resistance in the direction perpendicular to the surface of the immersion water becomes very small, and no strong conveyance force or strong wafer gripping force is required to overcome this. Can be prevented.

  In addition, it is not necessary to keep the conveyance speed much lower in consideration of breakage. Further, when a support roller is provided so that the flat surface of the semiconductor wafer is substantially vertical, the semiconductor wafer is substantially in contact with the water surface. Therefore, the transport distance and time in water can be shortened, and the total aligning time can be shortened.

  As described above, bringing the support posture at the time of aligning, the posture at the time of transport, and the transport direction within substantially the same vertical plane (that is, a plane perpendicular to the water surface) aligns efficiently in water. This is one of the features of the present invention that makes this possible.

  FIG. 1 is a front view of an underwater aligning device to which the present invention is applied, and FIG. 2 is a side view of the underwater aligning device. 3 and 4 are enlarged views of main parts of FIG.

  The underwater aligning device 1 to which the present invention is applied includes an immersion water tank 11. The immersion water tank 11 includes an inlet 111 for allowing the immersion water to flow in and an outlet 112 for allowing the immersion water to flow out from the vicinity of the water surface when the injected immersion water exceeds a predetermined water level. Since contaminants are likely to collect near the water surface, the entire immersion water can be prevented from being contaminated by allowing the immersion water to flow out from the vicinity of the water surface. The discharge port 113 is used to drain all the immersion water for maintenance of the apparatus.

  The semiconductor wafer W provided with the notch N is supported by a plurality of support rollers 21 and 22 in the immersion water stretched in the immersion water tank 11 with the flat surface P being substantially vertical. Be made.

  One support roller 21 is fixed to and supported by the rotation shaft 211. A roller arm 23 is provided so as to be able to swing around the rotating shaft 211. An arm fixing shaft 221 is provided in the vicinity of the opposite end of the roller arm 23, and the other support roller 22 is provided so as to be rotatable around the arm fixing shaft 221.

  A longitudinal groove 231 is formed in the length direction at the end of the roller arm 23 (upper side in FIG. 1). The swing drive source 24 includes a swingable drive arm 241, and a swing pin 243 is fixed on the side opposite to the swing center 242. The swing pin 243 is fitted in the longitudinal groove 231 of the roller arm 23, and when the drive arm 241 swings by the swing drive source 24, the roller arm 23 also swings.

  By swinging the drive arm 241 by the swing drive source 24 and opening the pair of left and right roller arms 23 upward, the support pulley is retracted and the semiconductor wafer W can pass between the two support rollers 22. It becomes like this. On the other hand, by closing the pair of roller arms 23, the carried semiconductor wafer W is sandwiched by a total of four support rollers 21 and 22 and supported thereby.

  The support rollers 21 and 22 are respectively provided with coaxial and integral roller pulleys 21p and 22p. When the roller pulleys 21p and 22p rotate, the support rollers 21 and 22 also rotate. A drive belt 253 is stretched between the roller pulleys 21p and 22p.

  A driving pulley 21q is further fixed to the rotating shaft 211. A drive belt 251 is stretched between the left and right drive pulleys 21q and another drive pulley 252. The driving pulley 252 is rotationally driven by the belt driving device 25.

  When the driving pulley 252 is rotated by the belt driving device 25, this rotation is transmitted to the driving pulley 252, the driving belt 251, the driving pulley 21q, the rotating shaft 211, the roller pulley 21p, the driving belt 253, and the roller pulley 22p. As a result, since the four support rollers 21 and 22 are rotationally driven in the same direction by the belt driving device 25, the semiconductor wafer W supported by them is also rotated.

  An optical notch sensor 3 that optically detects the notch N of the semiconductor wafer W is disposed in the immersion water tank 11. The optical notch sensor 3 is disposed in water so that the peripheral edge of the semiconductor wafer W supported by the support rollers 21 and 22 is desired, and when the notch N formed in the peripheral edge rotates to this arrangement position, Is detected.

  The optical notch sensor 3 is coupled to a light emitting and receiving device 31 installed at one end outside the immersion water tank 11 and has a pair of optical fiber sensors 321 arranged so that the other ends face each other and the peripheral edge of the semiconductor wafer W is desired. 322. Further, the optical notch sensor 3 is provided with a bubble removing device 33, from the nozzle 331 toward the gap between the optical fiber sensors 321 and 322 over which the peripheral edge is desired, that is, toward the optical path of the optical notch sensor 3. By ejecting water, bubbles that block the optical path that prevents normal detection are removed.

  A mechanical notch engaging device 4 is provided on the downstream side of the optical notch sensor 3 when viewed in the rotation direction of the semiconductor wafer W. The mechanical notch engaging device 4 includes an engaging claw 41 that can be mechanically engaged with the notch N, an engaging claw urging device 42, and an engagement sensor 43. The engaging claw urging device 42 can urge the engaging claw 41 toward the peripheral edge of the semiconductor wafer W, and can switch between the urging state and the urging release state. The engagement sensor 43 detects that the engagement claw 41 is engaged with the notch N (or is not engaged).

  The engaging claw 41 is provided at one end of the claw lever 421. The claw lever 421 is fixed to a shaft bar 411 that can freely rotate within the adjustment sleeve 412. The adjustment sleeve 412 includes a threaded portion 4121 and a flange 4124. A mounting hole 4131 is provided at an appropriate position of the water tank wall 413 in the immersion water tank 11. The adjustment sleeve 412 is attached to the water tank wall 413 by an adjustment nut 4122. A watertight bellows 4123 is provided between the water tank wall 413 and the flange 4124.

  By adjusting the screwing amount of the adjustment nut 4122, the axial position of the shaft bar 411 can be adjusted. Further, since the engaging claw 41 has the same cross-sectional contour shape along the rotation axis direction of the semiconductor wafer W, the position of the claw lever 421 attached to the shaft rod 411 and the engaging claw 41 at the tip thereof ( It is possible to change the contact position with the notch N along this direction by changing the arrow in FIG.

  A weight lever 422 is fixed to the other end of the shaft rod 411 (outside the immersion water tank 11), and an adjustment weight 44 is slidably mounted on the weight lever 422. The adjustment weight 44 is urged toward the weight lever 422 by the leaf spring 441, and an appropriate frictional resistance is given. For this reason, the adjustment weight 44 can be slid, and the axial position on the weight lever 422 can be adjusted.

  The weight of the adjustment weight 44 causes a biasing force to rotate the weight lever 422 and the claw lever 421 counterclockwise, and the biasing force of the engagement claw 41 toward the semiconductor wafer W by adjusting the position of the adjustment weight 44. The size of can be adjusted. The adjustment of the magnitude of the urging force is not only based on the position adjustment of the adjustment weight 44, but also any other configuration, for example, a configuration in which the piston rod 451 of the air cylinder 45 and the weight lever 422 are directly connected. In this case, the magnitude of the urging force is obtained by adjusting the pressure of the air supplied to the air cylinder 45.

  Since the air cylinder 45 can push up the weight lever 422 by its piston rod 451, the air cylinder 45 is operated by a control device described later, and the biasing state and biasing releasing state of the engaging claw 41 to the semiconductor wafer W are performed. Can be switched.

  The transfer device 5 includes a hand 51 and a transfer control device 52, and transfers the semiconductor wafer W from the outside of the underwater aligning device 1 to the support position by the support roller 21, and from the support position to the outside of the device. . The semiconductor wafer W is transported along the flat surface P of the semiconductor wafer W by the transport device 5 while at least a part of the semiconductor wafer W is in the immersion water. Since the attitude in which the semiconductor wafer W is supported and the direction in which the semiconductor wafer W is supported are in the same plane (on the vertical plane V in FIG. 2), the semiconductor wafer W does not include movement in a direction perpendicular to the plane while the semiconductor wafer is being transferred in immersion water. .

  When the hand 51 is carried in for alignment, after the semiconductor wafer W is transferred to the support rollers 21 and 22, the hand 51 is horizontal (left direction in FIG. 2) so that the gripping claws do not interfere with the semiconductor wafer W. It goes without saying that after the alignment, the opposite course is taken.

  For this reason, the resistance of immersion water can be minimized. This eliminates the resistance in the direction perpendicular to the surface of the immersion water, and no strong conveyance force or strong wafer gripping force is required to overcome this, preventing damage to the semiconductor wafer caused by these. be able to. Since the flat surface P is transported and supported along the vertical surface, the transport distance of the semiconductor wafer in water can be shortened, and the entire alignment processing time can be shortened.

  The control device 6 rotates the semiconductor wafer W supported by the support rollers 21 and 22, and when the optical notch sensor 3 detects the notch N, the control claw urging device 42 of the mechanical notch engagement device 4 is moved. Switch to energized state. At this time, in order to detect the notch N more reliably and prevent the semiconductor wafer W and the engaging claw 41 from being scratched or worn, the rotation speed of the semiconductor wafer W is changed from the first speed to the second speed lower than this. It is also possible to switch. Then, when the engagement sensor 43 detects that the engagement claw 41 is engaged with the notch N by further rotation of the semiconductor wafer W, the belt drive device 25 is controlled to stop.

FIG. 1 is a front view of an underwater aligning device to which the present invention is applied. FIG. 2 is a side view of the underwater aligning device. FIG. 3 is an enlarged view of a main part. FIG. 4 is an enlarged view of a main part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Underwater aligning apparatus 11 Immersion tank 111 Inlet 112 Outlet 113 Outlet 21 Support roller 211 Rotating shaft 21p Roller pulley 21q Drive pulley 22 Support roller 221 Arm fixed shaft 22p Roller pulley 23 Roller arm 231 Vertical groove 24 Swing drive source 241 Drive Arm 242 Swing center 243 Swing pin 25 Belt drive device 251 Drive belt 252 Drive pulley 253 Drive belt 3 Optical notch sensor 31 Light emitting / receiving device 321, 322 Optical fiber sensor 33 Bubble removing device 331 Nozzle 4 Mechanical notch engagement device 41 engaging claw 411 shaft rod 412 adjusting sleeve 4121 screw part 4122 adjusting nut 4123 watertight bellows 4124 flange 413 bracket 4131 mounting hole 42 engaging claw biasing device 421 claw lever 22 weight lever 43 engages sensor 44 tuning weights 441 leaf spring 45 an air cylinder 451 piston rod 5 carrying device 51 hand 52 transport controller 6 control device N notched P flat surface V vertical plane W semiconductor wafer

Claims (7)

An immersion water tank provided with an outlet for allowing the immersion water to flow in and an outlet for flowing out of the vicinity of the water surface when the injected immersion water exceeds a predetermined water level;
A plurality of support rollers for supporting and rotating a semiconductor wafer having a notch in the immersion water in the immersion water tank;
A drive belt for rotating the support roller;
A belt driving device for driving the driving belt;
An optical notch sensor that optically detects when the peripheral edge of the semiconductor wafer is placed in water as desired, and the notch formed in the peripheral edge rotates to this arrangement position;
A bubble removing device for removing bubbles blocking the optical path of the optical notch sensor;
A mechanical notch engagement device comprising:
An engaging claw mechanically engageable with the notch,
An engaging claw urging device capable of urging the engaging claw toward the peripheral edge of the semiconductor wafer, and capable of switching between an urging state and an urging release state; and
A mechanical notch engagement device having an engagement sensor for detecting when the engagement claw is engaged with the notch;
A transfer device for carrying the semiconductor wafer into and out of a support position by the support roller; and
A control device that rotates the semiconductor wafer supported by the support roller, and when the optical notch sensor detects the notch, the engaging claw urging device is switched to an urging state; A notch characterized by comprising a control device for controlling the belt drive device to stop when the engagement sensor detects that the engagement claw is engaged with the notch by further rotation. Underwater aligner for semiconductor wafer with An underwater aligning device for a semiconductor wafer with a notch according to claim 1,
The bubble removing apparatus includes a nozzle for ejecting water toward an optical path of the optical notch sensor, and an underwater aligning apparatus for a semiconductor wafer having a notch. An underwater aligning device for a semiconductor wafer with a notch according to claim 2,
The optical notch sensor includes a pair of optical fiber sensors, one end of which is coupled to a light emitting and receiving device installed outside the immersion water tank, and the other end of the optical notch sensor is disposed so as to face the peripheral portion of the semiconductor wafer. An underwater aligning device for a semiconductor wafer having a notch characterized in that: An underwater aligning device for a semiconductor wafer with a notch according to claim 3,
The control device is capable of switching the rotational speed of the semiconductor wafer from a first speed to a second speed lower than the first speed when the engaging claw urging device is switched to the urging state. An underwater aligner for semiconductor wafers with notches. An underwater aligning device for a semiconductor wafer with a notch according to claim 4,
The engaging claw has the same cross-sectional outline shape along the rotation axis direction of the semiconductor wafer, and the contact position with the notch can be changed along this direction. Underwater aligner for semiconductor wafers with notches. An underwater aligning device for a semiconductor wafer with a notch according to claim 5,
Some of the plurality of support rollers are on the transport path of the semiconductor wafer, and when the transport device transports the semiconductor wafer, the support rollers are temporarily retracted from the transport path to a retracted position. Thus, the semiconductor wafer having a notch is characterized in that the semiconductor wafer can be transported along a flat surface thereof without receiving a large immersion water resistance in the front direction. Underwater aligning device for. An underwater aligning device for a semiconductor wafer with a notch according to claim 6,
An underwater aligning device for a semiconductor wafer having a notch, wherein the support roller supports the semiconductor wafer in a state where a flat surface thereof is substantially vertical.

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