Temperature controlled chuck for elevated temperature etch processing

• US 4,971,653 A
• Filed: 03/14/1990
• Issued: 11/20/1990
• Est. Priority Date: 03/14/1990
• Status: Expired due to Term

• Current Assignee: Excelsus Technologies, Inc (Yageo Corporation)
• Original Assignee: Matrix Integrated Systems, Inc. (Axcelis Technologies Incorporated)
• Inventors: Drage, David J., Sie, Tony, Powell, Gary B.
• Primary Examiner(s): Powell, William A.
• Application Number:
  US07/494,173
• Time in Patent Office: 251 Days
• Field of Search: 156/643, 156/646, 156/345, 156/626, 156/627, 204/192.32, 204/192.33, 204/298.32, 204/298.39, 427/38, 427/39, 118/50.1, 118/620, 118/724
• US Class Current: 438/5
• CPC Class Codes: H01L 21/67069 for drying etching

Abstract

A parallel plate plasma type etching apparatus is provided with a temperature control chuck 44 so that elevated substrate temperatures are controlled. With an elevated substrate temperature, the reaction rate is increased. With positive temperature control, the likelihood of damage to the semiconductor devices is significantly reduced. The chuck is provided with a large number of equally spaced electrical heaters 72 and control of the heaters is by a temperature sensor 74.

Claims

1. In a method of etching a substrate exposed to a plasma generated by subjecting a reactant gas to an RF field while the substrate is supported on a chuck, the steps of increasing etch reaction rate without increased likelihood of substrate damage by controlling the temperature level of the chuck to a predetermined elevated level but below a temperature level at which degradation of the material exposed to said plasma occurs by sensing a temperature in the vicinity of the chuck to produce a control signal which is applied to a chuck temperature control means to maintain the chuck temperature at said predetermined level.

2. In a method of etching a substrate exposed to a plasma generated by subjecting a reactant gas to an RF field while the substrate is supported on a chuck, the steps of increasing the etch rate by controlling the temperature level of the chuck to a predetermined elevated level but below a temperature level at which degradation of a material exposed to said plasma occurs by sensing the temperature of the chuck and adding heat to said chuck in response to sensed chuck temperature lower than said predetermined high level.

3. The method as defined in claim 2 wherein the chuck is provided with a number of bores that are uniformly spaced and electrical heating elements are located in said bores, and further comprising the step of producing a control signal in response to the temperature that is sensed in said chuck to control the heat produced by respective ones of said electrical heating elements.

4. The method as defined in claim 3 further comprising providing a uniform temperature gradient for said chuck by providing a plurality of temperature sensing elements that are equal in number to one-half the number of heating elements with heating elements on opposite sides of a temperature sensing element being controlled in response to the temperature detected at an intermediate temperature sensing element.

5. Apparatus for plasma etching of a substrate comprising:

a housing having a base;

first and second electrodes coupled to an RF generator for producing a plasma between said electrodes;

one of said electrodes being mounted on said base by a heat insulation member so as to support a substrate at a location to be exposed to said plasma on a surface of a chuck;

mean associated with said chuck to maintain the chuck at a predetermined temperature that is elevated relative to a plasma produced chuck temperature;

means for sensing the temperature of said chuck and producing a control signal in response to a chuck temperature is less than said predetermined temperature; and

means connecting said control signal to said chuck temperature control means to provide an increased substrate reaction rate without increased likelihood of substrate damage.

6. Apparatus as defined in claim 5 wherein the chuck contains a number of bores that are uniformly spaced and have electrical heating elements located therein, and wherein said heating elements are electrically connected to operate in response to said control signal.

7. Apparatus as defined in claim 6 wherein the temperature sensing means comprises a plurality of temperature sensing elements that are equal in number to one half the number of heating elements with heating elements on opposite sides of a temperature sensing element being controlled in response to the temperature detected at an intermediate temperature sensing element.

8. Apparatus for plasma etching of a substrate comprising:

an upper electrode coupled to a power source;

a lower electrode coupled to ground and underlying a chuck surface for supporting said substrate;

a grid having openings defined therein which is disposed between said upper electrode and said lower electrode, said grid being coupled to ground; and

means for increasing the substrate etch rate without increased likelihood of substrate damage by controlling the temperature of the chuck surface to a predetermined elevated temperature level above about 100°

C. and below the temperature level at which degradation of a material in said apparatus occurs including;

means associated with said chuck to control the chuck temperature;

means responsive to the temperature of said chuck for producing a signal indicative of a chuck surface temperature departure from said predetermined temperature level; and

means connecting said control signal to said chuck temperature control means to maintain the chuck surface temperature substantially equal to said predetermined temperature.

9. Apparatus as defined in claim 8 wherein the chuck contains a number of bores that are uniformly spaced and have electrical heating elements located therein, said heating elements being electrically connected to operate in response to said control signal.

10. Apparatus as defined in claim 9 wherein the temperature sensing means comprise a plurality of temperature sensing elements that are equal in number to one half the number of heating elements with heating elements on opposite sides of a temperature sensing element being controlled in response to the temperature detected at an intermediate temperature sensing element.