JPH09111339A - Production of quasi-stable austenitic stainless steel thin sheet for id brade substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a quasi-stable austenitic stainless thin steel sheet for an ID brade substrate excellent in strength and fracture elongation by using a steel in which the contents of C, Si, Mn, Ni, Cr and Cu are specified and specifying the relation between the rolling ratio and rolling temp. in final rolling. SOLUTION: The compsn. of a quasi-stable austenitic stainless steel for an ID brade substrate is composed of the one contg., by weight, 0.01 to 2% C, 0.05 to 3% Si, 0.08 to 3% Mn, 6 to 7.4% Ni, 13 to 20% Cr and 0.05 to 0.5% Cu. At the time of rolling this steel, in the case the rolling ratio in final rolling is defined as CR (%) and the rolling temp. as T ( deg.C), the relation in the inequality: 60<=CR<=(T+123)/3.32 is made valid. By this rolling, strain induced martensitic phases are formed. Thus, the quasi-stable austenitic stainless steel for an ID brade substrate having about >=170kgf/mm<2> tensile strength and about >=1.5% fracture elongation can be obtd.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention mainly relates to Si, G
The present invention relates to a method for producing a metastable austenitic stainless steel thin plate for a substrate of an ID blade used when cutting a wafer from a semiconductor single crystal ingot 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. 2 shows a stress-strain curve obtained by the 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 the precipitation hardening stainless steels described in JP-A-61-295356 and JP-A-4-202643, the strengthening mechanism is due to the precipitation of fine intermetallic compounds, so that they break. Even if the material has a high ductility (for example, a breaking elongation of 2% or more), 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 in the tensile test, and 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 Laid-Open 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%. In addition, the value of elongation at break varies due to slight differences in manufacturing conditions,
If it is less than 1.0%, “pulling up” may not be possible, the breakage frequency during wafer cutting may vary, and the reliability of the material may be greatly impaired.

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

[0012]

The above problems can be solved by a method for producing a metastable austenitic stainless steel thin plate for an ID blade substrate, which is characterized by satisfying the following conditions.

(1) C: 0.01 to 0.2 by weight%
%, Si: 0.05 to 3%, Mn: 0.08 to 3%, N
i: 6 to 7.4%, Cr: 13 to 20%, Cu: 0.0
It consists of steel containing 5 to 0.5%.

(2) The rolling ratio of the final rolling for forming the work-induced martensite phase is CR [%], and the rolling temperature is T.
When the temperature is [° C.], the formula (a) is provided between the CR and the T.
Holds. 60 ≦ CR ≦ (T + 123) /3.32 (a) The reason for the limitation will be described below.

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 cannot be obtained. If it exceeds 0.2%, a large amount of Cr carbide is precipitated, resulting in deterioration of corrosion resistance and ductility.

Si: 0.05% or more is necessary to solid-solution 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. 0.08% or more is required for single-phase austenite phase and deoxidation during solution treatment, but if it exceeds 3%, the austenite phase is over-stabilized and the formation of work-induced mattensite phase is extremely suppressed. 170kgf /
A tensile strength of mm ² or more cannot be obtained.

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 required for making the austenite phase into a single phase during the solution treatment, but if it exceeds 7.4%, the austenite phase is excessively stabilized and the formation of the work-induced martensite phase is extremely suppressed, and 170 kgf / Mm ² or more tensile strength 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 to provide 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, it is necessary not only to adjust these components within an appropriate range, but also to form a work-induced martensite phase in the austenite phase of the parent phase by rolling.

Using a cold-rolled sheet of metastable austenitic stainless steel for an ID blade substrate manufactured by a conventional method,
Tensile strength and elongation at break were investigated by changing the rolling ratio and rolling temperature of the final rolling. After the final rolling, 450 ℃ × 3
Aging treatment of 0 seconds is performed.

FIG. 1 shows the relationship between tensile strength, elongation at break, rolling rate and rolling temperature. As is clear from this figure, if the rolling ratio and rolling temperature that satisfy the formula (a) are selected, it is possible to obtain a tensile strength of 170 kgf / mm ² or more and a breaking elongation of 1.5% or more at the same time. Recognize.

The cause of this is not always clear, but it is considered that the following two effects are produced by controlling the rolling temperature for forming the martensite phase within the range of the present invention.

Since the martensite phase is less likely to occur,
The rolling rate for ensuring an appropriate amount of martensite needs to be higher than in the case of rolling at room temperature. For this reason,
Work-induced martensite with higher dislocation density is generated,
High strength is obtained.

Since some of the austenite phase is rolled at a high temperature, it remains untransformed. Therefore, when processed at room temperature, it transforms to martensite, and high ductility is obtained.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing a metastable austenitic stainless steel sheet according to the present invention, the production method before the final rolling is not particularly limited, but it is easy to produce it by an ordinary process. That is, a stainless steel slab having the components of the present invention is hot-rolled, annealed and pickled, and then cold-rolled and annealed several times if necessary. At this time, thin slab technology can also be applied to the slab production.

The annealing is preferably performed in a non-oxidizing atmosphere from the viewpoint of surface properties and corrosion resistance. Especially for the final annealing and aging treatment, H ₂ gas 70 vol. % Non-oxidizing atmosphere is preferred.

[0029]

EXAMPLE SUS3 having chemical components shown in Table 1
01 series steels A to G were melted, and steels excluding steel E were used,
A hot rolled steel strip having a plate thickness of 2.5 mm was manufactured under the conditions of a finishing temperature of 900 ° C. and a winding temperature of 750 ° C. Here, Steel A is a steel having the composition system of the present invention, and B and C have C contents of D and E.
Indicates the amount of Si, and F and G indicate the amount of Mn, which is a constituent steel outside the present invention. Steel E could not be hot-rolled due to the excessive Si content.

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, a second cold rolling was performed at a cold rolling rate of 0 to 70%, and a final annealing was performed at 1050 ° C. for 30 seconds. Then, the final rolling for forming the martensite phase is performed by changing the rolling temperature and the rolling rate as shown in Table 2 for steel A and Table 3 for steels B to G, and further 4
50 ° C x 30 seconds aging treatment, final thickness 0.15
30 mm samples were prepared.

For these samples, JIS-Z-224
Tensile test according to No. 1 (JIS 13B test piece, pulling speed 2
mm / min. ) 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 for Steel A and Table 3 for Steels BG. In Table 2, material No. Samples 1 to 8 are comparative materials, and the material No. Samples 9 to 15 are materials of the present invention. Material No. satisfying the conditions of the present invention both in terms of components and final rolling conditions. Samples 9 to 15 have 17
It can be seen that it has a tensile strength of 0 kgf / mm ² or more 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.

On the other hand, although the components are within the scope of the present invention, the material No. having a rolling temperature or rolling ratio at the final rolling outside the scope of the present invention. The samples of 1 to 8 do not simultaneously satisfy the tensile strength of 170 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.

Similarly, although the final rolling conditions in Table 3 are within the scope of the present invention, the material No. whose components are outside the scope of the present invention. 16-3
The sample of 0 does not satisfy the tensile strength of 170 kgf / mm ² or more and the elongation at break of 1.5% or more at the same time.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

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

If the stainless steel thin plate manufactured by the method of the present invention is used, the frequency of breakage at the time of "pulling" when setting the ID blade in the cutting device and breakage at the time of wafer cutting can be remarkably reduced. It can greatly contribute to the improvement of stability and yield.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between tensile strength, elongation at break, rolling rate, and rolling temperature.

FIG. 2 is a diagram showing how to determine elongation at break.

Front Page Continuation (72) Inventor Kaoru Sato 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Masaki Omura 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. In the company

Claims (1)

[Claims] 1. A method for producing a metastable austenitic stainless steel thin plate for an ID blade substrate, which satisfies the following conditions. (1) In weight%, C: 0.01 to 0.2%, Si: 0.
05-3%, Mn: 0.08-3%, Ni: 6-7.4
%, Cr: 13 to 20%, Cu: 0.05 to 0.5%. (2) When the rolling ratio of the final rolling for forming the work-induced martensite phase is CR [%] and the rolling temperature is T [° C], the relationship between the CR and the T is expressed by the formula (a). It holds. 60 ≦ CR ≦ (T + 123) /3.32 ... (a)