Coating apparatus – Gas or vapor deposition – Multizone chamber
Reexamination Certificate
2000-01-13
2003-08-26
Bueker, Richard (Department: 1763)
Coating apparatus
Gas or vapor deposition
Multizone chamber
C118S724000, C118S729000
Reexamination Certificate
active
06610150
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to semiconductor wafer processing systems, apparatuses, and methods. In particular, the present invention relates to a structure with vertically-stacked process chambers which minimize the footprint while maximizing throughput of a semiconductor wafer processing system. For example, the present invention may be used to translate wafers within a near-atmospheric chemical vapor deposition (CVD) system, a rapid thermal oxidation system, or other types of wafer processing systems. The invention also particularly relates to a wafer transfer apparatus and method that moves semiconductor wafers between a loadlock chamber and a process chamber using a unitary transfer arm which pivots about a single rotational axis.
2. Description of Related Art
Conventionally, wafer transfer between loadlock chambers and process chambers is performed by complex apparatus. The complexity of the machinery has resulted in high cost of the apparatus, slow wafer processing and a short mean time between failures.
One example of a conventional wafer processing system is U.S. Pat. No. 4,934,315 to Linnebach et al. for “System for Producing Semiconductor Layer Structures By Way of Epitaxial Growth”. This multiple reactor chamber system accepts wafers for processing, where the wafers are loaded into respective holders in an atmospheric handler. The holders and wafers are stacked in a load chamber where each holder, carrying its respective wafer, is subsequently transferred along a linear path through the multiple reactor chambers. The reactor chambers are horizontally aligned along the linear path.
U.S. Pat. No. 4,822,756 to Hirayama for “Reaction Furnace and Method of Operating the Same” discloses a reaction furnace including a wafer support boat which rolls from an elevator capsule through a loading chamber and into a treatment chamber. Although the loading chambers and the treatment chambers appear to be stacked in a vertical direction, the pressure gas system and vacuum system are horizontally disposed from the treatment chambers and thus disadvantageously increases the footprint of the reaction furnace.
U.S. Pat. No. 4,423,701 to Nath et al. for “Glow Discharge Deposition Apparatus Including a Non-Horizontally Disposed Cathode” discloses a multiple chamber glow discharge deposition apparatus having deposition chambers which vertically orient the wafers or substrates for processing. The deposition chambers are shown to be horizontally oriented with respect to one another. A rotatable arm expels the substrates from the chamber such that the arm pushes the substrates in one direction along channeled guides.
U.S. Pat. No. 4,816,098 to Davis et al. for “Apparatus for Transferring Workpieces” discloses a system in which wafers are loaded onto the system in a vacuum wafer carrier which is held under vacuum to reduce contamination of the wafers. The wafers are transferred into a cluster tool having multiple process modules via a vacuum loadlock and a 2-axis robot arm which only has the capability of transporting a single wafer at a time.
U.S. Pat. No. 5,664,254 to Ohkura et al. for “Substrate Processing Apparatus and Substrate Processing Method” discloses a stacking arrangement for a plurality of process units. Although the process units may be vertically stacked, only one main handler is provided for transferring substrates to each of the process units, whereby the throughput of each process unit cannot be maximized. The patent also discloses a plurality of holding arms arranged in a 3-stage structure for transferring a substrate or wafer. The holding arms are mounted on the main handler and are actuated by a complex arrangement including a vertical drive shaft and motor in combination with a horizontally oriented convey base having a drive motor and belt to actuate each holding arm.
U.S. Pat. No. 5,058,526 to Matsushita et al. for “Vertical Load Lock Reduced-Pressure Type Chemical Vapor Deposition Apparatus” discloses a loading/unloading chamber which is similar to a loadlock chamber found in a conventional cluster tool. A cooler including refrigerant-circulating tubes located in an unloading part of a loading/unloading chamber cools the treated wafers.
U.S. Pat. No. 5,664,925 to Muka et al. for “Batchloader for Load Lock” discloses a conventional single-wafer scissor-type transfer arm. Similar conventional single-wafer scissor-type transfer arms are disclosed by U.S. Pat. No. 5,613,821 to Muka et al. for “Cluster Tool Batchloader of Substrate Carrier” and U.S. Pat. No. 5,607,276 to Muka et al. for “Batchloader for Substrate Carrier on Load Lock”.
U.S. Pat. No. 5,778,968 to Hendrickson et al. for “Method for Heating or Cooling Wafers” discloses a method for heating or cooling a substrate enclosed vacuum chamber using gas having an adjustable pressure above the wafer. Similarly, U.S. Pat. No. 5,588,827 to Muka for “Passive Gas Substrate Thermal Conditioning Apparatus and Method” discloses a heat transfer plate, located in a thermal conditioning chamber, which is either heated or cooled to change the temperature of a substrate.
SUMMARY OF THE INVENTION
A semiconductor substrate or wafer processing system and a substrate or wafer transfer apparatus in accordance with the present invention overcomes the disadvantages of conventional systems discussed above. In accordance with the present invention, a semiconductor wafer processing system includes a multi-chamber module, the multi-chamber module having a plurality of vertically-stacked loadlock-process chamber assemblies, an atmospheric-pressure front end unit having an atmospheric-pressure front end robot for transporting semiconductor wafers between a wafer cassette and the loadlock-process chamber assemblies, a common process chemical delivery system for each stack of chamber assemblies, and a dedicated wafer transfer apparatus for each loadlock-process chamber assembly. The processing system may also include two or more multi-chamber modules oriented in a linear array. A loadlock chamber is dedicated to each process chamber, the chambers together forming a respective loadlock-process chamber assembly. A cooling plate is disposed within each loadlock chamber below a single-pivot transfer arm of the wafer transfer apparatus. The cooling plate is provided with lift pins for removing wafers from the pivot transfer arm. A wafer chuck assembly having a chuck clamping surface and pins is provided within each process chamber for positioning wafers within the process chamber. In one embodiment of the present invention, the wafer chuck assembly translates a wafer within the process chamber past a chemical vapor deposition injector for processing.
One wafer transfer apparatus serves each loadlock-process chamber assembly. Each wafer transfer apparatus includes a transfer arm adapted to carry and transfer two or more wafers between the loadlock chamber and the process chamber. The transfer arm pivots about a single pivot axis extending through the loadlock chamber. The transfer apparatus has the capacity to simultaneously carry two wafers between the loadlock chamber and the process chamber. The wafer transfer apparatus also includes a retracted/home position and an extended position, wherein the single pivot axis allows the transfer arm to pivot between the retracted and extended positions. The cooling plate is disposed below the pivot arm when the pivot arm is in the retracted position. The wafer transfer apparatus also includes a lower wafer shelf and an upper wafer shelf integrated within the transfer arm.
Another aspect of the present invention is directed to a method of transferring the unprocessed wafer from the loadlock chamber to the process chamber, transferring the unprocessed wafer from the upper wafer shelf to a semiconductor wafer chuck mounted in the process chamber, translating the semiconductor wafer chuck from a retracted position, to an extended position where the wafer is processed, simultaneously transferring the processed wafer and a second unprocessed wafer between
Carvalheira Helder R.
Cossentine Dan L.
Mayer Bruce E.
Menagh Frank S.
Savage Richard N.
ASML US, Inc.
Bueker Richard
Dorsey & Whitney LLP
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