System and methods for etching a silicon wafer using HF and ozone

• US 20050215063A1
• Filed: 10/27/2004
• Published: 09/29/2005
• Est. Priority Date: 05/09/1997
• Status: Abandoned Application

• Current Assignee: Semitool Incorporated (Applied Materials Incorporated)
• Original Assignee: Semitool Incorporated (Applied Materials Incorporated)
• Inventors: Bergman, Eric J.
• Application Number:
  US10/975,194
• Publication Number:
  US 20050215063A1
• Time in Patent Office: Days
• US Class Current: 438/710
• CPC Class Codes: B08B 2203/005 the liquid being ozonated
• CPC Class Codes: B08B 2203/007 Heating the liquid
• CPC Class Codes: B08B 2230/01 Cleaning with steam
• CPC Class Codes: B08B 3/00 Cleaning by methods involving the use or presence of liquid or steam B08B9/00 takes precedence
• CPC Class Codes: B08B 3/02 Cleaning by the force of jets or sprays
• CPC Class Codes: B08B 3/044 using agitated containers in which the liquid and articles or material are placed by means of ultrasonic vibrations B08B3/12; cleaning casks or barrels by agitating B08B9/0817; mixers with shaking, oscillating or vibrating mechanisms B01F31/00
• CPC Class Codes: B08B 3/08 the liquid having chemical or dissolving effect substances used, see the relevant classes
• CPC Class Codes: B08B 7/00 Cleaning by methods not provided for in a single other subclass or a single group in this subclass
• CPC Class Codes: B81C 1/00547 Etching processes not provided for in groups B81C1/00531 - B81C1/00539
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/6704 for wet cleaning or washing
• CPC Class Codes: H01L 21/67051 using mainly spraying means, e.g. nozzles
• CPC Class Codes: H01L 21/6708 using mainly spraying means, e.g. nozzles
• CPC Class Codes: H01L 23/49582 Metallic layers on lead frames
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 3/3426 characterised by the leads
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

In a method of etching a silicon wafer in a controllable cost-effective manner with minimal chemical consumption, ozone gas and HF vapor are delivered into a process chamber to react with a silicon surface of the wafer. The ozone and HF vapor may be delivered sequentially, or may be mixed together before entering the process chamber. The ozone oxidizes the silicon surface of the wafer, while the HF vapor etches away the oxidized silicon. In alternative embodiments, HF may be delivered into the process chamber as an anhydrous gas or in aqueous form.

Claims

1. A method of etching one or more wafers, comprising:

placing the wafer into a process chamber;

delivering ozone gas into the process chamber;

oxidizing a wafer surface with the ozone;

delivering HF vapor into the process chamber; and

etching the oxidized wafer surface with the HF vapor.

2. The method of claim 1 wherein the HF vapor is delivered into the process chamber via a carrier gas.

3. The method of claim 2 wherein the carrier gas comprises ozone.

4. The method of claim 2 wherein the carrier gas comprises an inert gas.

5. The method of claim 4 wherein the inert gas is mixed with the ozone before the ozone enters the process chamber, such that the ozone and the HF vapor are simultaneously delivered to the wafer.

6. The method of claim 1 further comprising the step of forming a condensate film of HF vapor on a surface of the wafer.

7. A method of etching one or more silicon wafers, comprising:

placing the wafer into a process chamber;

delivering ozone gas into the process chamber to oxidize a layer of silicon on the wafer;

delivering anhydrous HF gas into the process chamber;

spraying DI water onto a surface of the wafer substantially simultaneously with the step of delivering anhydrous HF gas into the process chamber;

dissolving at least some of the anhydrous HF gas into the DI water on the wafer surface; and

etching the oxidized silicon layer with the dissolved anhydrous HF gas.

8. The method of claim 7 wherein the ozone gas and the anhydrous HF gas are mixed with one another before being delivered into the process chamber.

9. The method of claim 7 further comprising the step of forming a boundary layer of DI water on the surface of the wafer.

10. The method of claim 7 further comprising the step of spinning the wafer.

11. A method of etching one or more silicon wafers, comprising:

placing the wafer into a process chamber;

delivering ozone gas into the process chamber to oxidize a layer of silicon on the wafer;

delivering HF into the process chamber to etch the oxidized layer; and

forming a microscopic aqueous layer on the wafer surface.

12. The method of claim 11 wherein the HF is delivered into the process chamber in vapor form.

13. The method of claim 12 wherein the HF vapor is delivered into the process chamber via a carrier gas.

14. The method of claim 13 wherein the ozone acts as the carrier gas.

15. The method of claim 11 wherein the ozone gas and the HF are mixed together before being delivered into the process chamber.