JP3177937B2 - Manufacturing method of semiconductor silicon wafer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor silicon wafer having no local residual distortion (hereinafter, may be simply referred to as a wafer).

[0002]

2. Related Art Normally, wafers are washed after mirror polishing and then shipped. However, in the case of wafers after mirror polishing, scratches that become apparent upon selective etching,
That is, what is called a latent wound often appears. Scratches are known as damage to mirror-polished wafers. The difference between scratches and latent scratches is that the former can be determined visually, while the latter cannot be determined visually. The presence of latent scratches on the surface of the wafer may adversely affect the performance and yield of semiconductor devices formed thereon, which may be a problem.

[0003]

The inventor of the present invention has found that this latent scratch is a relatively weak localized area that is generated when a wafer surface is pressed or rubbed by a very fine foreign substance mixed in an abrasive or a polishing pad. It was clarified that the residual strain was great. The inventor of the present invention has further studied the means for erasing the latent flaw, and as a result, found that the latent flaw can be eliminated by a low-temperature, short-time heat treatment of the wafer, and reached the present invention.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor silicon wafer capable of easily eliminating latent scratches, which are relatively weak local residual strains.

[0005]

In order to solve the above-mentioned problems, in the method of the present invention, a semiconductor silicon wafer which has been subjected to mirror polishing and then washed is subjected to an inert gas or an acid.
Heat treatment was performed at 400 to 800 ° C. for 1 to 30 minutes in a raw gas atmosphere to eliminate latent scratches.

[0006] The heat treatment is preferably performed at 500 to 800 ° C, more preferably at 600 to 700 ° C. The upper limit of the heat treatment time is preferably 20 minutes or less, more preferably 10 minutes or less, and most preferably 5 minutes or less.

The heat treatment atmosphere is not particularly limited, but O ₂ may be used in addition to an inert gas such as N ₂ or Ar.

[0008]

Embodiments of the present invention will be described below.

Example 1 Sample wafer: CZ, p-type, <100>, 150 mm
φ, semiconductor silicon wafer (cleaning after mirror polishing) Insertion temperature into furnace: 400 ° C. Heat treatment: 400 ° C., 2 minutes, temperature taken out of furnace under nitrogen atmosphere: 400 ° C. The above heat treatment conditions are shown in FIG.

Under the above conditions, the sample wafer is heat-treated,
Then, selective etching [selective etching solution, 50% H
F: 61% HNO ₃ : CH ₃ COOH: H ₂ O = 1: 1
5: 3: 3 (volume ratio), etching time: 2 minutes]. A micrograph of the wafer surface is shown in FIG.

Example 2 Sample wafer: CZ, p-type, <111>, 150 mm
φ, semiconductor silicon wafer (cleaning after mirror polishing)

Heat treatment and selective etching were performed in the same manner as in Example 1 except that the above-mentioned sample wafer was used instead of the sample wafer of Example 1, and a micrograph of the wafer surface was taken and shown in FIG. Was.

Example 3 Insertion temperature into furnace: 400 ° C. Temperature rise: 6 ° C./min Heat treatment: 650 ° C., 2 minutes, nitrogen atmosphere Removal temperature from furnace: 400 ° C. Temperature drop: 10 ° C./min It is shown in FIG.

A heat treatment and a selective etching were carried out in the same manner as in Example 1 except that the above heat treatment conditions were used instead of the heat treatment conditions of Example 1, and a micrograph of the wafer surface was shown in FIG. .

Example 4 Sample wafer: CZ, p-type, <111>, 150 mm
φ, semiconductor silicon wafer (cleaning after mirror polishing)

A heat treatment and a selective etching were carried out in the same manner as in Example 3 except that the above-mentioned sample wafer was used instead of the sample wafer of Example 3, and a micrograph of the wafer surface was shown in FIG. .

Example 5 Insertion temperature into furnace: 400 ° C. Temperature rise: 6 ° C./min Heat treatment: 800 ° C., 2 minutes, nitrogen atmosphere Removal temperature from furnace: 400 ° C. Temperature drop: 10 ° C./min 11 is shown.

Heat treatment and selective etching were carried out in the same manner as in Example 1 except that the above heat treatment conditions were used instead of the heat treatment conditions in Example 1, and a micrograph of the wafer surface was shown in FIG. .

Example 6 Sample wafer: CZ, p-type, <111>, 150 mm
φ, semiconductor silicon wafer (cleaning after mirror polishing)

Heat treatment and selective etching were carried out in the same manner as in Example 5 except that the above-mentioned sample wafer was used instead of the sample wafer of Example 5, and a micrograph of the wafer surface was shown in FIG. .

Comparative Example 1 Selective etching was performed in the same manner as in Example 1 except that no heat treatment was performed, and a micrograph of the wafer surface was taken and shown in FIG.

Comparative Example 2 Selective etching was performed in the same manner as in Example 2 except that no heat treatment was performed, and a microphotograph of the wafer surface was shown in FIG. From the results of each of the above examples, it was confirmed that the latent heat on the wafer surface was eliminated or significantly reduced by performing the heat treatment under the conditions of the present invention. From the results of the comparative examples, it was confirmed that there were many latent scratches when the heat treatment was not performed. Further, although a p-type wafer is shown in the examples, it has been confirmed that the same effect can be obtained for an n-type wafer.

[0023]

As described above, according to the present invention, it is possible to eliminate or significantly reduce latent scratches, which are local residual distortions of a mirror-finished wafer, by adding a simple process. It works.

[Brief description of the drawings]

FIG. 1 is a photomicrograph of a wafer surface obtained in Example 1.

FIG. 2 is a micrograph of the wafer surface obtained in Example 2.

FIG. 3 is a micrograph of a wafer surface obtained in Example 3.

FIG. 4 is a micrograph of a wafer surface obtained in Example 4.

FIG. 5 is a micrograph of the wafer surface obtained in Example 5.

FIG. 6 is a micrograph of the wafer surface obtained in Example 6.

FIG. 7 is a micrograph of the wafer surface obtained in Comparative Example 1.

FIG. 8 is a micrograph of the wafer surface obtained in Comparative Example 2.

FIG. 9 is an explanatory view showing heat treatment conditions in Examples 1 and 2.

FIG. 10 is an explanatory diagram showing heat treatment conditions in Examples 3 and 4.

FIG. 11 is an explanatory diagram showing heat treatment conditions in Examples 5 and 6.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kiyoshi Suzuki 150 Ohira, Odakura, Nishigo-mura, Nishishirakawa-gun, Fukushima Prefecture Shin-Etsu Semiconductor Co., Ltd. Semiconductor Shirakawa Research Laboratories JP-A-4-64238 (JP, A) JP-A-4-354136 (JP, A) JP-A-2-220443 (JP, A) JP-A-2-177542 (JP, A) Int.Cl. ⁷ , DB name) H01L 21/26-21/268 H01L 21/322-21/326 H01L 21/304

Claims (3)

(57) [Claims] 1. A semiconductor silicon wafer which has been mirror-polished and then cleaned, is subjected to an inert gas or oxygen gas atmosphere.
A heat treatment at 400 to 800 [deg.] C. for 1 to 30 minutes to eliminate latent scratches. 2. The heat treatment at 500 to 800 ° C. for 1 to 1
2. The method according to claim 1, wherein the method is performed for 0 minutes. 3. The heat treatment at 600 to 700 ° C. for 1 to 5
2. The method according to claim 1, wherein the step is performed for one minute.