Vacuum processing system

• US 5,445,484 A
• Filed: 10/04/1993
• Issued: 08/29/1995
• Est. Priority Date: 11/26/1990
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Itou, Atsushi, Tsubone, Tsunehiko, Tamura, Naoyuki, Kato, Shigekazu, Nishihata, Kouji
• Primary Examiner(s): Werner, Frank E.
• Application Number:
  US08/131,911
• Time in Patent Office: 694 Days
• Field of Search: 414/331, 414/222, 414/416, 414/417, 414/935, 414/937, 414/939, 414/940, 414/941, 414/217, 118/719, 204/298.25
• US Class Current: 414/217
• CPC Class Codes: H01L 21/67778 involving loading and unloading of wafers
• CPC Class Codes: Y10S 414/137 including means for charging or discharging wafer cassette
• CPC Class Codes: Y10S 414/139 including wafer charging or discharging means for vacuum chamber
• CPC Class Codes: Y10S 414/14 Wafer cassette transporting

Abstract

A vacuum processing system of a type in which wafer cassettes each accommodating a plurality of wafers to be treated are supplied to deliver the wafers and wafer cassettes collecting the treated wafers are taken out. To enable the vacuum treatment, the vacuum processing system has a structure comprising:

a plurality of wafer cassettes each being set in the atmospheric air and holding a plurality of wafers to be treated; at least one vacuum processing chamber for effecting vacuum treatment on the wafers; at least one load-lock chamber disposed between the cassettes and the vacuum processing chamber, the wafers being transferred into and out of vacuum atmosphere in the vacuum processing chamber through the load-lock chamber; and a wafer transfer device for transferring the wafers from each of the cassettes to the load-lock chamber and vice versa. The wafer cassettes are arranged on a substantially horizontal flat surface with respect to each other and each of the cassettes has two upper and lower stationary positions, and the transference of the wafers from and into each of the cassettes is conducted at one of the upper and lower stationary positions.

Claims

1. A wafer processing system comprising:

two cassettes each having a plurality of wafers stored at respective locations therein;

first and second cassette stands for supporting respective ones of said two cassettes in horizontally spaced relation without a separator at a boundary therebetween;

means for moving respective ones of each of said first and second cassette stands between first and second vertically spaced positions;

a vacuum processing chamber for processing said wafers in a vacuum condition therein;

wafer transfer means located between said cassette stands and said vacuum processing chamber for transferring said wafers between each cassette, when its associated cassette stand is held in its first position, and said vacuum processing chamber; and

cassette supply and take-out means for supplying and taking out a cassette to and from one of said first and second cassette stands in its first position when the other of said first and second cassette stands is in its second position.

2. A wafer processing system according to claim 1, wherein said wafer transfer means transfers the wafers in each cassette without requiring that said cassette be moved from its first position.

3. A wafer processing system with an accommodation for a plurality of cassettes each having a plurality of locations at which respective wafers are stored comprising:

a plurality of cassette stands for installing respective cassettes in horizontally spaced relation in an atmospheric air, each of said cassette stands having a stationary position when said wafers are accessed and having means for moving respective ones of each of said plurality of cassette stands between first and second vertically spaced positions, for exchanging a cassette on one of said cassette stands with a new cassette when said one cassette stand is in its first position and another of said cassette stands is in its second position;

a vacuum processing chamber for processing said wafers in a vacuum condition therein;

a wafer transfer unit including a wafer transfer robot for transferring wafers, said wafer transfer robot being movable across wafer transfer paths between said plurality of cassette stands and said vacuum processing chamber, and in a height direction for accessing said locations in said cassettes installed on said cassette stands to take in/out said wafers;

a load-lock chamber disposed along said wafer transfer paths between said transfer robot and said vacuum processing chamber for transferring said wafers therethrough in said atmospheric air when said wafers are received from a cassette and in said vacuum condition when said wafers are supplied to said processing chamber; and

an unload-lock chamber disposed along said wafer transfer paths between said transfer robot and said vacuum processing chamber for transferring said wafers therethrough in said atmospheric air when said wafers are supplied to a cassette and in said vacuum condition when said wafers are received from said processing chamber.

4. A wafer processing system according to claim 3, wherein said wafer transfer robot is movable to all locations in each of said cassettes held in said cassette stands for accessing all locations in said cassettes while the positions of said cassettes is unchanged.

5. A wafer processing system with an accommodation for two cassettes each having a plurality of locations at which respective wafers are stored comprising:

two cassette stands for installing respective cassettes in horizontally spaced relation without a separator at a boundary therebetween in an atmospheric air, each cassette stand having means for moving the associated cassette stand between first and second positions vertically spaced from one another;

means for exchanging one cassette installed on one of said two cassette stands with a new cassette when said one of said two cassette stands is in said first position and the other of said two cassette stands on which another cassette is installed is in said second position;

a vacuum processing chamber for processing said wafers in a vacuum condition therein; and

wafer transfer means located between said cassette stands and said vacuum processing chamber for transferring said wafers between each of said cassettes installed on said cassette stands in said first position and said vacuum processing chamber.