KR20000048997A - Wafer gripping device - Google Patents

Abstract

PURPOSE: An apparatus for gripping a wafer is provided to remove a wafer horizontally loaded in a container from the container, and to rotate the wafer to be transferred to a processing carrier. CONSTITUTION: An apparatus(1) for gripping a wafers(3) loaded in a container(4), the wafers being separated from each other, comprises a holding rake(10) having a slot(11). The slot includes a stop surface(9') for stopping on an edge of the wafer, suitable for receiving the wafer and a gripping head(6,6'). The slot is capable of rotating regarding the holding rake.

Description

Wafer Gripper Device {WAFER GRIPPING DEVICE}

When processing a wafer (semiconductor wafer), it is necessary to go through various processing steps. Conventionally, raw wafers have been produced and stored in containers in the middle. For actual processing operations, these raw wafers must be removed from the container, fed to the device for processing and then loaded back into the container. The basic problem that occurs during this entire process and intermediate storage step is that the wafer must be kept away from contaminants and dirt. Even the smallest contamination by dust or other particles can damage the wafer surface. This damage significantly increases the defective rate of the final product produced from this wafer. Therefore, it is generally processed by clean room technology. In other words, the processing area must maintain a defined cleanness for the dust particles. The same applies to the middle storage, that is, the storage container.

Removal and transfer of the wafer is done manually or automatically. Manual operation is more likely to be contaminated, so automatic operation is preferred.

Conventionally, such wafers have been produced and processed up to 200 mm in diameter. The wafer is stored vertically upright in the cassette made for this wafer. To remove and transport, the wafer must be taken out of the cassette in a vertical position and transferred back to this cassette. For this purpose, suitable devices for stopping at the edge of the wafer are known. The wafer is inserted into a rake type of hoisting device that can move in and out of the cassette. The houlding device is made such that the edge area of the wafer is partially exposed so that the removal device can be applied to this edge. The wafer is brought into contact by the device only at the edges extending perpendicular to the surface as well as in a narrowly defined area around the backside.

In particular, newer and larger wafers (over 300 mm) are currently on the market and are mostly stored horizontally in containers rather than vertically. The wafer is removed from the container and then rotated by 90 ° to another location before being fed to the downstream processing apparatus. Devices for such removal and rotational movements are not yet known.

The present invention relates to a device for gripping a wafer according to claim 1 and a method for fixing and transporting a wafer according to claim 14.

1 shows a gripping apparatus according to the present invention prior to removing a wafer from a container;

2 shows the gripping apparatus of FIG. 1 while transferring a wafer to a processing carrier;

3 is a longitudinal sectional view of a gripping device according to the present invention;

4 is a top side view of the gripping apparatus according to the invention shown in FIG. 3;

5 is a top side view of another gripping device according to the present invention;

6 is a longitudinal sectional view of the gripping apparatus according to the present invention for securing each wafer.

7 is a top side view of the gripping apparatus according to the invention shown in FIG.

It is an object of the present invention to provide a gripping apparatus capable of removing a wafer stored horizontally in a container and rotating the wafer to transfer it to a processing carrier.

According to the invention, this object is achieved by the features of claim 1. The structure of the gripping device according to the invention can remove the horizontally placed wafers from the storage container, rotate them, transfer them to the processing carrier and place them thereon. This satisfies the requirement regarding the wafer that it must not be contacted by all objects. This is because the gripping device actually contacts the wafer only at the edges, not at the wafer surface. Nevertheless, this wafer can be stably supported and can be rotated and moved to any desired position. This is done completely automatically. This device can be installed and operated with the processing machine stopped.

Preferred embodiments of the invention are described in claims 2 to 12. In addition, a preferred method of the invention is described in claim 13.

In order to move the gripping head between the loaded wafers, it is advantageous to rotate it by 90 ° to a slide-in position. In this position, the head can move without contacting the surface of the wafer at all, without causing any problems into the spaces between the wafers.

Due to the preferred structure of the holding and slot surfaces, the wafers only contact the edges and do not actually contact the surfaces. This is because the slot surface is inclined toward the bottom surface of the wafer.

The same effect can be obtained due to the structure of the holdering lake or the structure of the slot according to the invention. In this case, the stop area that comes into contact with the bottom surface of the wafer is provided with precision. However, this area is very small and within acceptable tolerances for wafer fabrication. Despite this small surface, the wafer can fit tightly without changing position and spacing.

Advantageously, each of the two gripping heads is provided for one wafer. The paired gripping heads are spaced apart from each other and stop at the edge region of one wafer. For example, it is clear that all gripping heads must move together at the same time to secure a wafer load.

Preferably, the gripping device according to the invention is used in a wafer-processing system.

The present invention also proposes a treatment method according to claim 14 to achieve the above object. The process according to the preferred embodiment is described in claims 15-18.

Advantageously the gripping device is raised slightly by the present invention before the loaded wafer is removed from the container to discharge the wafer from the holdering device. This prevents damage to the wafer surface due to the holdering charges, which are damaged when the wafer is pulled outward and slides against the holdering charge.

Embodiments of the present invention are described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the gripping device 1 according to the invention is arranged on a movable, rotary carrier 2. The unprocessed wafers 3 are arranged horizontally and parallel to each other in the container 4. In this case, the wafer 3 is stored in the container 4 so that only the narrow edges of the wafer edge and the wafer bottom are in contact with the holling elements in the container 4.

After the fabrication process, the wafer 3 is stored in the container 4 and stored in the container until transferred to another processing step. The gripping device shown here is used to pull the wafer 3 out of the container 4 and transfer it to the processing carrier 5. As shown, the process carrier 5 is a structure consisting of two rollers 5 which are placed parallel to each other and on which the round wafers 3 are arranged vertically.

The container 4 is transferred to the discharge position by a controlled delivery device. In this release position, the opening of the vehicle is arranged in the clean room. In this position, the front cover of the container 4 is removed and the wafer 3 is accessible to the gripping device 1. This position is shown schematically in FIG. 1.

The gripping device 1 is moved by the carrier 2 in front of the container 4 opening and the gripping device secures the wafer 3 to the gripping device 1. Thereafter, the gripping apparatus 1 together with the wafer 3 can be moved out of the container 4 and, due to the movement of the carrier 2, rotate to achieve the desired vertical alignment.

2 shows the wafer 3 rotating vertically on the processing carrier 5. The roller 5 'of the processing carrier 5 has the roller 3' rotated by the rotation of the roller 5 'around the axis after the wafer 3 is moved down between the rollers 5'. ) To be positioned with the top edge. For example, the roller 5 'has a circular cross section which is horizontal when rotated by 90 degrees.

By lowering the carrier 2, the gripping device 1 can move outwards between the wafers 3, which are transported by the processing carrier 5 to the processing station.

After the processing is completed, the processed wafer 3 is transferred back to the container 4 by the gripping apparatus 1 and then moved forward.

Since the whole operation is automatic and does not require any manual operation, the operation takes place in a clean space of the processing machine. This advantageously reduces the risk of contamination during the machining process and the defective rate of the wafer 3 compared to manually transporting and removing the wafer and speeds up the processing.

The structure of the gripping apparatus 1 according to the present invention is a longitudinal cross-sectional view, which is shown in detail in FIG. 3.

In order to pull the wafer 3 out of the container 4, a gripping head 6 is provided, which is arranged at one end of the longitudinally moving rod 7 which rotates about an axis.

The gripping head 6 comprises a slot 8, the width of which is made somewhat wider than the thickness of the wafer 3, and the lower cheek 8 ′ disposed on the bottom surface of the wafer 3. ) Is aligned at an acute angle to the wafer surface.

As shown in FIG. 3, dragging the rod 7 in the direction of the arrow allows the gripping head 6 to be pulled against the transverse edge of the corresponding wafer 3. This movement is generated by the corresponding movement of the overall gripping apparatus 1. As a result, the transverse edge of the wafer 3 stops at the bottom of the slot 8. According to the structure of the slot 8 with the lower cheeks arranged at an angle, the wafer 3 does not contact the gripping device.

For example, FIG. 4 shows a gripping head 6 having two different structures. The upper gripping head 6 is formed to hold only one wafer 3 and includes only one slot 8. The gripping head is used in the gripping device 1 as a line portion and a rear portion. The gripping head 6 ′ disposed below is formed to hold two wafers 3 simultaneously and includes a second cutout 9 in addition to the lower slot 8. This cut portion 9 has a vertical stop surface 9 "as well as a cheek surface 9 'aligned at an acute angle with respect to the wafer surface.

The hoisting rake 10 is provided as a corresponding portion of the gripping head 6, 6 ′. This holding rake 10 also includes a slot 11 for receiving the wafer 3. This slot is made in the shape of a wedge, and each lower slot surface has a short region 11 'disposed parallel to the wafer surface. The depth of this region is not longer than the width of the region on the bottom surface of the wafer 3 allowed for this apparatus. However, the slot 11 is in principle made to coincide with the slot of the gripping heads 6, 6 ′. Because of the relative movement of the rod 7 with respect to the hoisting rake 10, the rake 3 is firmly fixed without applying a large force. The clamp 3 can securely hold the wafer 3, which allows rotational movement of the wafer 3 from the horizontal position to the vertical position. Advantageously, in each case a rotational movement takes place so that the wafer lies on the bottom surface with respect to the holdering lake 10. As a result, in the vertical position the gripping heads 6 and 6 'are removed where the head is stopped at the wafer edge by the displacement and rotation of the rod 7 and the structure of the holding lake 10 according to the invention. Thus, the wafer 3 maintains its position.

4 is a top side view of the gripping apparatus 1 according to FIG. 3. 4 shows the gripping head 6 in a fixed position, as described above. The wafer 3 is fixed between the gripping head 6 and the holding lake 10 by the movement of the rod 7 in the direction of the arrow.

Instead of applying and fixing a force, the gripping head 6 can be placed in a fixed position because the diameter of the wafer 3 is accurate. This prevents deformation and damage of the wafer 3 due to the contact pressure. The shape of the gripping head 6 and the hoisting rake 10 allows for precise positioning with virtually no play while allowing rotational movement of the entire device.

The movement of the gripping head 6 and the rod 7 is by hydraulic, pneumatic or electric drive.

4 shows the gripping head 6 'in the rotated position. For this purpose, the rod 7 moves away from the hoisting lake 10 in the direction of the arrow and then rotates 90 °. The holding head 6 'can move between two adjacent wafers 3. This movement is carried out while the gripping device 1 is brought into the container 4 to remove the wafer 3 while the gripping device 1 is pulled in from the processing carrier 5 and when the processing operation is finished. (4) It is required while moving out.

4 shows two possible arrangements of the holdering lake 10. The upper part of FIG. 4 shows, for example, a hoisting lake 10 arranged in the transverse direction with respect to the rod 7. The hoisting rake may be arranged between the rods 7, as indicated by 10 '. The hoisting rake 10 is arranged in a single part or multiple parts, and the rod 7 is placed next to the hoisting rake 10 or is guided to the recess via the hoisting rake 10.

5-7 show a gripping device according to two embodiments of the present invention, which is consistent with the gripping device shown in FIGS. In order to avoid repeated explanation, only the differences between the embodiments are described below.

The gripping device shown in FIG. 5 is a multiple gripping device in which the structure of the two-piece holding rakes 10, 10 ′, rods 7 and gripping heads 6, 6 ′ are shown in FIG. 3. It corresponds to the component shown in 4. Alternatively, in the gripping apparatus, the counterholder 16 can be disposed between the two rods 7 and move longitudinally parallel to the longitudinal axis of the rods 7. The counterholder 16 is arranged on the side facing the gripping heads 6, 6 ′ with respect to the wafer 3. In addition, the counterholder 16 includes respective slots for accommodating the wafer 3, the width of each slot being longer than the thickness of the wafer, so that the wafer surface does not contact the counterholder 16.

In order to remove the wafer 3 from the container, the rod 7 is moved by the forward movement of the gripping device 1 along the longitudinal axis parallel to the wafer surface so that the gripping head is placed behind the wafer 3. Thereafter, the gripping head rotates by 90 ° and the gripping device moves backward until the wafer is supported against the gripping head 6,6 'in the slot 8,9.

The counterholder 16 moves forward in the direction of the gripping heads 6 and 6 'until the circumference of the wafer 3 is disposed in the slot of the counterholder. The shape of the counterholder 16 slots ensures that the wafer surface is not damaged.

The wafer 3 fixedly supported by the three points between the counter holder 16 and the gripping heads 6 and 6 'is slightly lifted by the corresponding movement of the gripping apparatus 1, and the wafer is lifted into the container. No longer located The wafer is then removed from the container by a removal movement in the direction of the arrow 17.

In order to vertically align the wafer by 90 °, a hoisting rake 10, 10 ′ is used that moves up to the wafer 3 while advancing parallel to the rod 7. Thus, as described above, the wafer 3 is disposed in the slot 11 of the holdering lakes 10, 10 '. After the counter holder 16 moves back from the wafer while moving in the opposite direction of the forwarding movement of the holding rakes 10 and 10 ′, the wafer 3 is rotated to be placed vertically and see FIGS. 1 to 4. It is arranged in the processing carrier 5 as described.

Even in this case, the processed wafer can be placed back in the container using the gripping apparatus by applying the processing steps in reverse.

In principle, the present invention is applied to processing each wafer as needed during the processing of each wafer 3. For this purpose, FIGS. 5 and 6 show a corresponding embodiment in which the slot 11 of the holdering lake 10 comprises inclined surfaces 12, 13. The gripping head 6 provided for each wafer includes inclined slot surfaces 14, 15.

When the wafer is gripped, its edge is placed in the counter holder 16 as well as the two gripping heads 6 as shown in FIG. This allows the wafer 3 to move in the gripping device 1 without a large relative movement between the gripping device and the wafer 3. For this purpose, the counterholder comprises an elastomeric stop face 16 'aligned at right angles to the surface of the wafer 3. This method allows the wafer 3 to be removed from the container and transferred to the hoisting rake 10 without having to vibrate the gripping head 6 when machining. Preferably, the counterholder 16 is disposed on and held on the wafer during the rotational motion of the gripping device, thereby achieving a high speed rotational motion while preventing undesirable vibrational motion of the wafer. Finally, it is advantageous for the gripping device not to contain any holding rakes, as the structural design is not as complex as possible when processing each wafer. The entire processing of the wafer is simplified by using two gripping heads 6 and counterholders 16 until the wafer is held in the container and placed on the processing carrier.

Claims (18)

In the gripping device 1 for the wafer 3 loaded in the container 4 spaced apart from each other, a gripping rake suitable for accommodating the wafer 3 and the gripping heads 6 and 6 'and 10. A gripping apparatus for a wafer, characterized in that it comprises a hoisting rake 10 having a slot 11, which includes a stop surface 9 "that can move and rotate about 10) and stop at the edge of the wafer. . According to claim 1, in the gripping device (1) for the wafer (3), which is placed in the container (4) spaced apart from each other, a counterholder (16) and a gripping head (for holding against the edge of the wafer) 6; 6 '), the gripping head can move and rotate relative to the counterholder 16 and has a stop surface 9 "for stopping at the edge of the wafer, so that the wafer can be fixed and the counter A gripping device for a wafer, characterized in that it is supported and processed against a holder (16) and two gripping heads. The gripping device according to claim 1, wherein the gripping head (6; 6 ′) can rotate 90 °. The gripping device according to claim 1, wherein the gripping head (6; 6 ′) is fixed to the end of the rod (7). The gripping device according to claim 1, wherein the gripping head (6: 6 ′) comprises at least one slotted surface (8 ′, 9 ′) inclined with respect to the wafer surface. The gripping apparatus as claimed in claim 1, wherein the stop surface (9 ″) is aligned at right angles to the wafer surface. The gripping apparatus as claimed in claim 1, wherein the gripping head is shorter than the mutual distance between the wafers in the container. The gripping device according to claim 1, wherein the hoisting rake (10, 11) comprises a multi-part structure. The gripping apparatus as claimed in claim 1, wherein in each slot at least one of the slot surfaces in each case comprises a region (11 ′) extending parallel to the wafer surface at the bottom of the slot. The gripping device according to claim 1, wherein a hydraulic, pneumatic or electric drive device for rotating and sliding the gripping head (6; 6 ′) operates in connection with the gripping head. In the above claim, in each case the two gripping heads 6; 6 ′ are arranged parallel to one another and move together and in each case are arranged to stop at the edge of the same wafer 3. Gripping device. The gripping device according to claim 1, wherein the hoisting rake is a component part consisting of multiple parts, in particular two parts. Use of a gripping apparatus according to claims 1 to 12 for removing, rotating and transporting a wafer (3) in a wafer-processing system. A gripping device 1 comprising a gripping device 6: 6 ′ and a holdering device 10, 16 is used for fixing and transporting the wafers, which are loaded in the container 4 away from each other. Thus, when the container 4 is open, the gripping means 6; 6 ′ move from the container opening between the wafers 3 to the edge opposite the container opening, and the gripping device moves the wafer 3. Direction is in contact with the edge of each wafer 3 by a traction movement, and the houlding device is brought into contact with the wafer edge by the relative motion between each wafer 3 and the houlding devices 10, 16, which are respectively In the case of a slot 11 for the wafer 3, the corresponding wafer is fixed between the holdering device 10, 16 and the gripping device 6, 6 ′, and the wafer 3 is placed in a container. The gripping device 1 is raised so as to be lifted from the supporting means arranged at (4), and the wa Buffer 3 and the gripping device (1) with the process of being removed from the container. The process according to claim 14, wherein after removing the wafer from the container, the gripping device (1) is rotated by 90 ° so that the wafer (3) is aligned perpendicular to the container (3). 16. The gripping device 6; 6 'is in a retracted position before moving between the wafers 3 and rotates to a fixed position before contacting the edge of the wafer 3, The rotation angle is 90 °. 17. The counterholder 16 of the hoisting device proceeds forward in the direction of the gripping device after the gripping device 6; 6 'comes into contact with the edge of the wafer 3. Thus, the wafer (3) is characterized in that in each case is held three points supported between the gripping device and the counter holder (16). 18. The method according to claim 15 and 17, after removal, before rotating the gripping device, the hoisting rake 10 moves to the edge of the wafer 3 and the counterholder 16 is removed from the wafer 3 again. Characterized in that the process.