Wafer transfer mechanism

• US 6,305,898 B1
• Filed: 07/16/1999
• Issued: 10/23/2001
• Est. Priority Date: 07/22/1998
• Status: Expired due to Fees

• Current Assignee: ASM Japan K.K. (ASM International NV)
• Original Assignee: ASM Japan K.K. (ASM International NV)
• Inventors: Furukawara, Kazunori, Suwada, Masaei, Yamagishi, Takayuki
• Primary Examiner(s): Underwood, Donald W.
• Application Number:
  US09/354,690
• Time in Patent Office: 830 Days
• Field of Search: 414/222.01, 414/744.4, 414/744.5, 414/744.6, 414/936, 414/937, 414/941, 414/806-810, 294/1.1, 294/103.1
• US Class Current: 414/744.5
• CPC Class Codes: H01L 21/67766 Mechanical parts of transfer devices robots in general in B25J
• CPC Class Codes: H01L 21/67778 involving loading and unloading of wafers
• CPC Class Codes: H01L 21/68 for positioning, orientation or alignment
• CPC Class Codes: H01L 21/68707 the wafers being placed on a robot blade, or gripped by a gripper for conveyance

Abstract

A transfer mechanism is provided for placing a wafer at a prescribed position on an arm without any additional step. The transfer mechanism for transferring a workpiece into and from a storage section comprises an arm member for holding a workpiece having a projection which can be contacted with an edge of the workpiece at the tip end portion thereof, a movement mechanism for reciprocating the arm member between a retracted and an extended positions while holding the workpiece thereon to transfer the workpiece to and from the storage section, and a positioning member which is positioned in the vicinity of the arm member and can be contacted with the edge of the workpiece for positioning the held workpiece in a prescribed position on the arm member. When the arm member is moved to the retracted position by the movement mechanism, the positioning member comes into contact with the edge of the workpiece held on the arm member to block only the movement of workpiece, thereby placing it in a prescribed location on the arm member.

Claims

1. A transfer mechanism for transferring a workpiece to or from a storage section, comprising:

(a) an arm member having a tip end portion for supporting a workpiece thereon, said tip end portion having at its distal end at least one projection adapted to be in contact with an edge of the workpiece for restricting movement of the workpiece toward the distal end;

(b) a movement mechanism for reciprocally moving the arm member between its retracted position and its extended position, while supporting said workpiece on said arm member, to transfer said workpiece to or from said storage section; and

(c) a positioning member for contacting an edge of the workpiece and moving the workpiece on the arm member in relation to the arm member toward the distal end when the arm member retracts, said positioning member being disposed in tracks of the arm member movement, at a fix position free from movement of the arm member,

wherein when said arm member is moved by said movement mechanism toward said retracted position, the edge of said workpiece supported on said arm member contacts said positioning member to block the movement of said workpiece and to place the workpiece on said arm member at a prescribed position between the projection and the positioning member.

2. The transfer mechanism of claim 1, wherein part of at least one of said positioning member and said projection, said part being contacted with the edge of said workpiece, has an elastic member.

3. The transfer mechanism of claim 1, wherein when said workpiece is placed at said prescribed position by moving said arm member toward said retracted position, said workpiece is contacted with and sandwiched between said projection and said positioning member.

4. The transfer mechanism of claim 1, wherein when said workpiece is placed at said prescribed position by moving said arm member toward said retracted position, a clearance is defined between the edge of said workpiece and said projection.

5. The transfer mechanism of claim 4, wherein said clearance is a distance of 2 mm or less.

6. The transfer mechanism of claim 1, wherein said storage section is a processing chamber, and

said transfer mechanism transfers said workpiece, which is placed at said prescribed position by moving said arm member to said retracted position, toward a processing position inside said processing chamber by moving said arm member to said extended position.

7. The transfer mechanism of claim 3 or 4, wherein a plurality of storage sections are provided, and

said transfer mechanism has moving means for moving said arm member toward each said storage section while keeping said arm member in said retracted position, and

said positioning member is connected to said moving means.

8. A method for transferring a workpiece from one storage section to another storage section, said method comprising the steps of:

(a) inserting an arm member having a tip end portion for supporting a workpiece thereon, into one storage section by extending the arm member to its extended position, said tip end portion having at its distal end at least one projection adapted to be in contact with an edge of the workpiece for restricting movement of the workpiece toward the distal end, at which extended position a clearance is defined between the edge of the workpiece contained in the storage section and the projection of the arm member, and then transferring the workpiece onto the arm member;

(b) retracting said arm member until the edge of said workpiece, which is transferred thereon, is contacted with a positioning member disposed in tracks of the arm member movement, at a fix position free from movement of the arm member;

(c) further retracting said arm member until said arm member arrives at a retracted position, said positioning member being in contact with said workpiece and blocking the movement thereof to move the workpiece on the arm member in relation to the arm member toward the distal end, so that said workpiece is places at a prescribed position on said arm member between the projection and the positioning member;

(d) moving said arm member toward said another storage section while keeping said arm member in said retracted position; and

(e) inserting said arm member into said another storage section while supporting said workpiece at said prescribed position on said arm member.

9. A transfer method as claim 8, wherein said clearance is greater than or equal to 2 mm.

10. A transfer method as claim 8, wherein said workpiece is sandwiched between said projection member and said positioning member when disposed at said prescribed position on said arm member.

11. The method of claim 8, wherein when placing said workpiece at said prescribed position on said arm member, a gap is defined between the edge of said workpiece and said projection member, and the gap is 1.5 mm or less.

12. The method of claim 8, wherein said another storage section is a processing chamber, and

said arm member is inserted into said processing chamber until it arrives at a processing position of said processing chamber.