JPH09111416A - Metastable austenitic stainless steel thin sheet for id brade substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a metastable austenitic stainelss steel thin sheet excellent in tensile strength and fracture elongation by specifying its compsn. and the ratio of strain induced martensitic phases. SOLUTION: This metastable austenitic stainless steel thin sheet for an ID brade substrate is composed of a steel contg., by weight, 0.1 to 0.3% N, 0.01 to 0.1% C, 0.05 to 3% Si, 0.08 to 3% Mn, <=0.045% P, <=0.02% S, <=0.003% Al, <=0.02% O, 6 to 7% Ni, 13 to 20% Cr and 0.05 to 0.5% Cu and furthermore contg. strain induced martensitic phases by >=30vol.%. This stainless steel has >=170kg/mm<2> tensile strength and >=1.5% fracture elongation. By using the stainless steel, the frequency of fracture in the case of raising at the time of setting an ID brade to a cutting device and fracture in the case of wafer cutting can remarkably be reduced, so that it can remarkably contribute to the improvement of the stability and yield in wafer production.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention mainly relates to Si, G
The present invention relates to a metastable austenitic stainless steel thin plate for a substrate of an ID blade used when cutting a wafer from an ingot of a semiconductor single crystal such as aAs.

[0002]

2. Description of the Related Art Strength and ductility are important properties required of a material for an ID blade substrate.

Regarding the strength, not only is it necessary to "pull up" the surface of the ID blade with a considerable surface tension when it is set in the cutting device, but it is necessary to increase the strength in order to withstand the cutting at high speed. Although desired, it has been examined by the present inventors that a tensile strength of 170 kgf / mm ² or more is required.

For ductility, the "pull up" of the blade
In order to give a strain of 0.9-1.0%, a breaking elongation of at least 1.0% was required, but there is a demand to reduce the breaking frequency of ID blades during single crystal cutting. It is becoming more and more severe, and breaking elongation of 1.5% or more is required. Further, it is desirable that the ductility be as high as possible in order to absorb the impact due to the vibration of the blade during the wafer cutting.

FIG. 1 shows a stress-strain curve obtained by a tensile test. The breaking elongation is the amount of strain (%) at the breaking position in FIG.

In addition, high rigidity, corrosion resistance, and low in-plane anisotropy of mechanical properties are also necessary properties for the material for the ID blade substrate.

Considering such required characteristics, precipitation hardening stainless steel and metastable austenitic stainless steel represented by SUS301 and SUS304 have been used as materials for ID blade substrates.

In the case of precipitation hardening stainless steel, since the strengthening mechanism is due to the precipitation of fine intermetallic compounds, they tend to be the starting points of fracture, and even if the material has high ductility (for example, elongation at break is 2 %), The blade may suddenly break during wafer cutting. Therefore, in the precipitation hardening stainless steel, the fracture resistance of the blade cannot be evaluated by the elongation at break of the tensile test,
Its quality control becomes difficult.

On the other hand, in the case of metastable austenitic stainless steel, Japanese Patent Publication No. 2-44891 and Japanese Patent Publication No.
As described in Japanese Patent Laid-Open No. 2026443, high strength is achieved by performing cold working after annealing to work-harden the work and generating a work-induced martensite phase, and then performing an aging treatment. However, problems such as those found in precipitation hardening stainless steel do not occur.

[0010]

However, in the metastable austenitic stainless steel, it is necessary to carry out a strong cold working to obtain high strength as described above, so that the breaking elongation is 1.0 to 1. Remarkably low at around 4%. Also, the breaking elongation value varies greatly due to slight differences in manufacturing conditions, and it becomes less than 1.0%, making it impossible to "pull up", and the breaking frequency during wafer cutting also varies, resulting in high material reliability. May be damaged.

The present invention has been made to solve the above problems, and is a metastable austenitic stainless steel for an ID blade substrate having a tensile strength of 170 kgf / mm ² or more and a breaking elongation of 1.5% or more. The purpose is to provide a thin plate.

[0012]

Means for Solving the Problems The above-mentioned problems are expressed in terms of% by weight,
N: 0.1 to 0.3%, C: 0.01 to 0.1%, S
i: 0.05 to 3%, Mn: 0.08 to 3%, P: 0.
045% or less, S: 0.02% or less, Al: 0.003
% Or less, O: 0.02% or less, Ni: 6 to 7.4%, C
r: 13 to 20%, Cu: 0.05 to 0.5%, and a work-induced martensite phase of 30 v.
ol. It is solved by a metastable austenitic stainless steel thin plate for an ID blade substrate, which is characterized by containing at least 50%.

The reason for the limitation will be described below. N: The most important element in the present invention. It promotes the generation of austenite phase and stabilizes the austenite phase during processing, which greatly contributes to the improvement of ductility. It also contributes to solid solution strengthening of the work-induced martensite phase and age hardening, and promotes higher strength. If it is less than 0.1%, the effect cannot be sufficiently obtained, and if it is more than 0.1%, it is more preferable, but if it exceeds 0.3%, blowholes occur during casting,
It requires slab care, resulting in high costs.

C: An element that suppresses the formation of the δ ferrite phase and promotes the formation of the austenite phase. In addition to controlling the amount and hardness of the martensite phase produced by processing, it also contributes to strengthening the solution by strengthening its solid solution and age hardening. If it is less than 0.01%, the effect is not sufficient. If it exceeds 0.1%, Cr carbides are precipitated, resulting in deterioration of corrosion resistance and ductility.

Si: 0.05% or more is required to strengthen the austenite phase and the work-induced martensite phase, but if it exceeds 3%, a δ ferrite phase is formed and hot workability is deteriorated.

Mn: an element that promotes the formation of an austenite phase, and is required to be 0.08% or more for the single phase formation and deoxidation of the austenite phase during solution treatment. Is stabilized, and the formation of a martensite phase is extremely suppressed, so that a tensile strength of 170 kgf / mm ² or more cannot be obtained.

P: an element effective for solid solution strengthening, but 0.
If it exceeds 045%, toughness is deteriorated.

If S: 0.02% is exceeded, non-metallic inclusions such as MnS are formed and the frequency of breakage of the ID blade is increased.

Al: an element necessary for deoxidation, but 0.0
If it exceeds 03%, non-metallic inclusions such as Al ₂ O ₃ are formed and the breakage frequency of the ID blade is increased.

O: When it exceeds 0.02%, Al ₂ O ₃ and M
A large number of non-metallic inclusions such as nO, SiO ₂ and Cr ₂ O ₃ are generated, which deteriorates hot workability and increases the frequency of breakage of the ID blade.

Ni: An element that promotes the formation of a strong austenite phase and suppresses the formation of the δ ferrite phase.
6% or more is necessary for making the austenite phase into a single phase during solution treatment, but if it exceeds 7.4%, the austenite phase is stabilized and the formation of the martensite phase is suppressed.
A tensile strength of kgf / mm ² or more cannot be obtained.

Cr: An essential element of stainless steel, 13% or more is necessary to obtain sufficient corrosion resistance, but 20%
If it exceeds, δ ferrite phase is generated and hot workability is deteriorated.

Cu: To strengthen the passivation film and impart the necessary corrosion resistance when used as an ID blade,
It is necessary to be 05% or more, but if it exceeds 0.5%, the effect is saturated, and undissolved C in the austenite phase is present.
u increases and hot workability deteriorates.

In order to obtain a tensile strength of 170 kgf / mm ² or more, not only these components are adjusted to an appropriate range, but also the work-induced martensite phase is added to the austenite phase of the parent phase in an amount of 30 vol. % Or more.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a metastable austenitic stainless steel sheet according to the present invention is not particularly specified, but the most convenient method is the ordinary step. That is, hot rolling a slab of stainless steel having the components of the present invention, after annealing / pickling, cold rolling / annealing is repeated several times as necessary, and the required amount of work-induced martensite phase is obtained by final cold rolling. It is formed and subjected to an aging treatment to be manufactured. At this time, thin slab technology can also be applied to the slab production.

The annealing is preferably carried out in a non-oxidizing atmosphere from the viewpoint of surface properties and corrosion resistance. Particularly, for annealing before the final cold rolling and for aging treatment after the final annealing, H ₂ gas 70 vol. % Non-oxidizing atmosphere is preferred.

The final cold rolling rate is preferably 40 to 70% in order to adjust the surface roughness of the final product and ensure higher ductility.

[0028]

EXAMPLE SUS3 having chemical components shown in Table 1
01 series steel No. 1-6 are melted, finishing temperature 900 ℃,
A hot-rolled steel strip having a plate thickness of 2.5 mm was manufactured under the condition of a coiling temperature of 750 ° C. Here, No. Nos. 3 to 5 are steels of the present invention and No.
1, 2, 6 are comparative steels. The comparative steel No. Since blowholes were generated in No. 6, the slab surface was cleaned before hot rolling.

This hot-rolled steel strip was annealed and pickled, and then cold-rolled for the first time at a cold rolling rate of 60% and then subjected to intermediate annealing at 1050 ° C. for 30 seconds. After that, the second cold rolling is performed at a cold rolling rate of 50 to 70%, a final annealing is performed at 1050 ° C. for 30 seconds, and the cold rolling rate is changed in the range of 40 to 70% to change the amount of martensite phase. The sample was changed and subjected to an aging treatment at 450 ° C. for 30 seconds to prepare 20 kinds of samples having a final plate thickness of 0.15 mm.

Then, according to JIS-Z-2241, the tensile test (JIS No. 13B test piece, pulling speed 2 mm / mi
n. ) Was carried out to determine the tensile strength and the elongation at break. Further, for some samples, after being processed into ID blades, they were mounted on a wafer cutting device, and the “pull-up” property and the frequency of breakage during cutting were also investigated.

The results are shown in Table 2. A sample having an amount of martensite within the range of the present invention is 170 kgf / mm ²
It can be seen that it has the above tensile strength and a breaking elongation of 1.5% or more. Further, even when it is actually used as an ID blade, the “pull-up” property is good and the break frequency during cutting is very low.

For samples with N content lower than the range of the present invention, 1
None of them simultaneously satisfy the tensile strength of 70 kgf / mm ² or more and the elongation at break of 1.5% or more. Therefore, there is a problem in "pull-up" property and breakage frequency during cutting. Note that N
For samples whose amount is higher than the range of the present invention, 170 kgf / m
Although the tensile strength of m ² or more and the elongation at break of 1.5% or more are satisfied at the same time, blowholes are generated as described above, and slab maintenance is required, resulting in high cost.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

Since the present invention is constructed as described above, the tensile strength of 170 kgf / mm ² or more and 1.
A metastable austenitic stainless steel thin plate for an ID blade substrate having a breaking elongation of 5% or more can be provided.

Using the stainless steel sheet of the present invention, I
Since the frequency of breakage at the time of “pulling up” when setting the D-blade in the cutting device and the breakage at the time of cutting the wafer can be significantly reduced, it can greatly contribute to the improvement of the stability of wafer manufacturing and the yield.

[Brief description of the drawings]

FIG. 1 is a diagram showing how to determine elongation at break.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kaoru Sato 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Masanori Omura 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Date Main Steel Pipe Co., Ltd.

Claims (1)

[Claims] 1. By weight%, N: 0.1-0.3%, C:
0.01-0.1%, Si: 0.05-3%, Mn:
0.08-3%, P: 0.045% or less, S: 0.02
% Or less, Al: 0.003% or less, O: 0.02% or less, Ni: 6 to 7.4%, Cr: 13 to 20%, Cu:
It is made of steel containing 0.05 to 0.5%, and has a work-induced martensite phase of 30 vol. % Or more, a metastable austenitic stainless steel thin plate for an ID blade substrate.