Heat treatment process for preventing slips in semiconductor wafers

• US 5,775,889 A
• Filed: 10/27/1995
• Issued: 07/07/1998
• Est. Priority Date: 05/17/1994
• Status: Expired due to Term

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Shimazu, Tomohisa, Takanabe, Eiichiro, Kobayashi, Junichi, Ushikawa, Harunori
• Primary Examiner(s): Kamen, Noah P.
• Application Number:
  US08/549,163
• Time in Patent Office: 984 Days
• Field of Search: 432/206, 432/4, 432/6, 432/12, 432/18
• US Class Current: 432/18
• CPC Class Codes: C23C 16/46 characterised by the method used for heating the substrate C23C16/48, C23C16/50 take precedence
• CPC Class Codes: C30B 31/12 Heating of the reaction chamber
• CPC Class Codes: C30B 31/14 Substrate holders or susceptors

Abstract

A heat treatment apparatus comprising a reaction vessel located in a vertical furnace, and a ladder boat for mounting a plurality of semiconductor wafers one above another in parallel with each other. A vertical mounting pitch of mounting the wafers on the ladder boat is set at, e.g., 40 mm. When a treatment temperature is 1000° C., intra-surface temperature differences of the wafers, objects to be treated, can be suppressed to 10° C. at the time of passing 900° C. even when 600° C. is raised to 100° C. at a 100° C./min rate, whereby no slip occurs in large-diameter semiconductor wafers of an above 250 mm diameter even with high temperature increases at high rates in heat treatments, as of oxidation, diffusion, etc.

Claims

1. A process for heat treating a plurality of semiconductor wafers in a substantially tubular reaction vessel located in a tubular furnace, each of said semiconductor wafers having a diameter of about 300 mm, said process comprising the steps of:

mounting said semiconductor wafers in parallel one above another in a mounting jig at a vertical mounting pitch of 18-20 mm;

loading said mounting jig having said semiconductor wafers mounted therein into said reaction vessel;

heating said semiconductor wafers to a temperature above 600°

C. and below 950°

C. at a rate in which the temperature increases by up to 10°

C./minute, a temperature above 950°

C. and below 1000°

C. at a rate in which the temperature increases by up to 40°

C./minute, a temperature above 1000°

C. and below 1025°

C. in which the temperature increases by up to 3°

C./minute, and a temperature above 1025°

C. and below 1050°

C. at a rate in which the temperature increases by up to 2°

C./minute, and cooling said semiconductor wafers from a temperature of 1050°

C. to 600°

C. at a rate in which the temperature decreases by up to 3°

C./minute.

2. The process defined by claim 1, wherein:

said mounting jig is a ladder boat having a vertical mounting pitch of about 18 mm.

3. The process defined by claim 1, wherein:

said mounting jig is a ring boat having a vertical mounting pitch of about 20 mm.