Ultra-pure stainless steel precision strip for semiconductors and consumer electronics and preparation method of ultra-pure stainless steel precision strip

Abstract

The invention discloses an ultra-pure stainless steel precision strip for semiconductors and consumer electronics and a preparation method of the ultra-pure stainless steel precision strip, and the ultra-pure stainless steel precision strip for semiconductors and consumer electronics comprises the following components in percentage by mass: 0.003-0.010% of C; 0.15% to 0.30% of Si; 16.5% to 17.0% of Cr; ni: 14.5 to 15.0%; 2.2 to 2.8% of Mo; 0.10% to 0.40% of Mn; 0.08 to 0.25 percent of Cu; 0.001% to 0.015% of N; o: 0.003% to 0.0015%; 0.001% to 0.01% of Al; 0.006 to 0.01 percent of S; 0.015% to 0.030% of P; 0.005% to 0.02% of Ca; nb is less than or equal to 0.05%; ti is less than or equal to 0.02%; less than or equal to 0.02% of Se; and the balance of iron and inevitable impurity elements. According to the formula, high-purity stainless steel for semiconductors or non-magnetic stainless steel of ultra-pure stainless steel for semiconductors can be prepared through the preparation method, and the prepared material has excellent corrosion resistance and oxidation resistance (the yield strength Rp0.2 value of the material is larger than or equal to 175 MPa, the tensile strength Rm value of the material is larger than or equal to 480 MPa, and the ductility A50 of the material is larger than or equal to 40%), has a high surface and a high plate shape and is suitable for semiconductor equipment and consumer electronic parts.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of stainless steel, in particular to an ultra-pure stainless steel precision strip for semiconductor and consumer electronics and a preparation method thereof. BACKGROUND

[0002] With the rapid development of the semiconductor and consumer electronics industry, the demand for alloy precision strips is rapidly increasing. The material is required to have high corrosion resistance, high surface and high purity. Under the trend of miniaturization and light weight, the thickness is also gradually developing from the conventional cold-rolled product 0.3mm or more to the precision thin material, and the thickness is 0.3mm or less to 0.01mm. The purity and performance requirements of the material become more stringent, especially in the process of manufacturing high-performance microelectronic devices. Stainless steel becomes an important material for semiconductor equipment due to its excellent corrosion resistance, processing performance and relatively high strength, which is used for chemical medium, gas pipeline and parts. However, any small material residue caused by stainless steel corrosion can cause great loss to the yield of semiconductor products. Therefore, it is necessary to prepare ultra-pure and high-purity stainless steel, which has extremely low impurity content, high cleanliness, excellent mechanical properties and corrosion resistance, so as to play an important role in the field of semiconductor manufacturing and the like.

[0003] Austenitic stainless steel has a face-centered cubic structure. In theory, fully annealed austenitic stainless steel has a single-phase austenitic structure. Corrosion resistance is the main function of stainless steel. It forms a passivation layer through Cr, and the passivation layer has self-repairing ability, thereby giving stainless steel corrosion resistance. Research shows that Cr, Mo and N are the main elements for improving corrosion resistance, and Mn and inclusions such as S and O have adverse effects on corrosion resistance, and elements such as Si and Cu improve the corrosion resistance of the material in acidic environments. Inclusions in stainless steel usually include oxides, sulfides, silicates and nitrides, which may be endogenous inclusions produced during smelting, pouring and solidification, or may be foreign inclusions remaining in the steel due to the failure of slag, refractory or other inclusions to float in time. The higher the purity of the steel, the less the inclusions, and the better the mechanical properties, corrosion resistance and formability of the steel. When the precision strip is rolled to 0.3mm, and part of the application is rolled to 0.01mm, the defects such as holes and buckling caused by purity seriously affect the product quality, and high purity must be controlled from the source. In the rolling process of the precision strip, the shape and surface control are also very important. Therefore, improving the purity, obtaining good shape and surface are important goals in the preparation process.

[0004] The prior art discloses:

[0005] CN202311827749 discloses a high-purity stainless steel billet prepared by a short process and a preparation method thereof. Through strict slagging process of intermediate frequency induction furnace, AOD furnace argon blowing and deoxidization process, LF furnace refining slag optimization, the content of inclusions and residual elements in LF refined molten steel and billet is reduced, and the quality of the billet is improved;

[0006] CN202310236988 discloses a titanium-containing stainless steel smelted by a single nozzle refining furnace and a refining method thereof. High-purity stainless steel liquid is obtained through vacuum refining and titanium alloying;

[0007] CN202410497782 discloses an ultra-high-purity stainless steel and a preparation method thereof. The electron beam refining is used to achieve deep removal of inclusions and realize high-purity preparation of stainless steel. The non-metallic inclusions meet the following conditions: coarse inclusions A, B, C and D are all 0; fine inclusions A, B and C are all 0, and fine inclusion D is 0.5;

[0008] CN201810132857 discloses a high-purity smelting method of stainless steel. Under the protection of high-purity argon, the mother alloy is smelted by electric arc, AOD+LF external refining, VD vacuum refining, and mold casting ingot process, so as to obtain a stainless steel ingot with low impurity content;

[0009] CN202111120319 discloses an ultra-pure stainless steel for semiconductor manufacturing industry. The mass percentage is: carbon 0.03, manganese 0.5, silicon 0.75, phosphorus 0.45, sulfur 0.005-0.010, chromium 16-18, nickel 10-14, molybdenum 2-3, copper 0.30, nitrogen 0.51, and the balance is iron. The stainless steel is prepared by a triple melting process, i.e., vacuum induction melting (VIM), electroslag remelting (ESR), and vacuum consumable arc melting (VAR), to form 316L stainless steel of HP, UHP grade for semiconductor manufacturing industry;

[0010] CN202411246064 discloses a smelting process of ultra-purity 316LUHP-A stainless steel for semiconductors. The special high-purity steel quenchant is used to prepare pure steel with extremely low phosphorus content, sulfur content and nitrogen content;

[0011] CN202211645399 discloses a high-strength austenitic stainless steel for ultra-pure electronic special gases in the semiconductor industry and a preparation method thereof. The chemical composition of the austenitic stainless steel is, in weight percentage, as follows: Cr: 24.0-30.0%, Ni: 25.0-40.0%, Mo: 4.0-8.0%, W: 0-3.0%, N: 0.1-1.0%, Se: 0-0.01%, Si<0.3%, C<0.01%, Mn<0.05%, Al<0.01%, P<0.005%, S<0.001%, O<0.004%, and the balance is iron. The "ultra-low carbon, low manganese" composition design concept is adopted to control the chromium equivalent and nickel equivalent to ensure a completely austenitic structure. A certain amount of nitrogen is added and homogenization heat treatment is used to promote the solid solution of nitrogen. Finally, the strength of the matrix is ​​improved through cold rolling. The purity smelting process is used to control the inclusion content in the steel and improve the corrosion resistance of the matrix grain boundaries, achieving the optimal combination of strength, toughness and corrosion resistance.

[0012] CN202211622329 discloses a high-purity austenitic stainless steel for electronic special gases in the semiconductor industry and a preparation method thereof. The chemical composition of the austenitic stainless steel is, by weight percentage, as follows: Cr: 16.0-18.0%, Ni: 12.0-15.0%, Mo: 2.0-3.0%, N: 0.1-1.0%, B: 0.001-0.02%, Ce: 0.0001-0.01%, Si <0.1%, C <0.01%, Mn <0.05%, Al <0.01%, P <0.004%, S <0.002%, O <0.003%, and the balance is iron. The austenitic stainless steel adopts an "ultra-low carbon and low manganese" composition design concept, controls the chromium equivalent and nickel equivalent, and ensures a completely austenitic structure.

[0013] CN202111120319 discloses an ultra-pure stainless steel for use in the semiconductor manufacturing industry. Through a special process of VIM+ESR+VAR triple melting, it is manufactured into HP and UHP grade 316L stainless steel that meets the application of the semiconductor manufacturing industry.

[0014] In summary, the chemical composition and preparation methods of stainless steel in existing technologies make it difficult to completely remove trace impurities such as S, P, and O from the raw materials. These impurities can negatively impact the performance of stainless steel and often fail to meet the ultra-high purity requirements of the semiconductor industry. Furthermore, oxygen can form hard inclusions such as aluminum oxide, adversely affecting processing and corrosion resistance.

[0015] Therefore, it is urgent to develop an ultra-pure stainless steel precision strip and a preparation method thereof, which can improve the overall corrosion resistance of the material, effectively reduce the impurity content in the stainless steel, and improve the purity of the stainless steel by matching the formula and process, modify the hard inclusions, and prepare high-surface and high-flatness products to meet the demand for high-performance precision materials in the semiconductor and consumer electronics fields. SUMMARY

[0016] The purpose of the present application is to provide an ultra-pure stainless steel precision strip for semiconductors and consumer electronics and a preparation method thereof. The formula can be used to prepare a non-magnetic stainless steel of high-purity stainless steel for semiconductors or ultra-pure stainless steel for semiconductors. The prepared material has excellent corrosion resistance and oxidation resistance (material yield strength Rp0.2 value ≥ 175 MPa, tensile strength Rm value ≥ 480 MPa, elongation A50 ≥ 40%), and the material is thinnest rolled to 0.01 mm through a rolling annealing process control, has high surface and high flatness, is suitable for semiconductor equipment and consumer electronics components, and can also take into account the material with ultra-high purity or high purity.

[0017] To achieve the above purpose, the following technical solutions are realized:

[0018] A precision stainless steel for semiconductors and consumer electronics, the composition of the stainless steel includes the following components in mass percentage:

[0019] C: 0.003-0.010%;

[0020] Si: 0.15-0.30%;

[0021] Cr: 16.5-17.0%;

[0022] Ni: 14.5-15.0%;

[0023] Mo: 2.2-2.8%;

[0024] Mn: 0.10-0.40%;

[0025] Cu: 0.08-0.25%;

[0026] N: 0.001-0.015%;

[0027] O: 0.003-0.0015%;

[0028] Al: 0.001-0.01%;

[0029] S: 0.006-0.01%;

[0030] P: 0.015-0.030%;

[0031] Ca: 0.005-0.02%;

[0032] Nb≤0.05%;

[0033] Ti≤0.02%;

[0034] Se≤0.02%;

[0035] the rest is iron and inevitable impurity elements.

[0036] As a further improvement of the present solution,

[0037] The elements in the precision stainless steel for semiconductor and consumer electronics shall meet the following relationship simultaneously: 1.25≤(Cr+Mo+1.5Si) / (30N+30C+0.25Cu+0.5Mn+Ni)≤1.33.

[0038] Ca:Al≥2.0;

[0039] Si:Al≥25.

[0040] As a further improvement of the present solution,

[0041] The four types of inclusions of the precision stainless steel for semiconductor and consumer electronics, sulfide type (A type), oxide type (B type), silicate type (C type) and spherical oxide type (D type), are all ≤0.5 level, the materials A, B and C prepared by ultra-pure process are 0 level and the material D is ≤0.5 level, the thinnest material can be rolled to 0.01mm without appearing holes and buckling, the yield strength Rp0.2 value of the material is ≥175MPa, the tensile strength Rm value is ≥480MPa and the elongation A50 is ≥40%.

[0042] As a further improvement of the present solution,

[0043] The precision stainless steel material for semiconductor and consumer electronics is suitable for semiconductor equipment and consumer electronic components.

[0044] A method for preparing a precision stainless steel for semiconductor and consumer electronics,

[0045] The high-purity stainless steel for semiconductor includes the following preparation steps:

[0046] The metal ingredients of the precision stainless steel for semiconductor and consumer electronics are vacuum induction melted, cast, forged, vacuum arc melted, solidified and forged or rolled.

[0047] The high-purity stainless steel for semiconductor is prepared through the above steps.

[0048] or

[0049] The ultra-pure stainless steel for semiconductor includes the following preparation steps:

[0050] The metal ingredients of the precision stainless steel for semiconductor and consumer electronics are vacuum induction melted, cast, forged or rolled.

[0051] The ultra-pure stainless steel for semiconductor is prepared through the above steps.

[0052] As a further improvement of the present application,

[0053] The billet or continuous casting billet is heated at a temperature range of 1100-1250 DEG C.

[0054] As a further improvement of the present application,

[0055] The forging or rolling is completed at a temperature of 900 DEG C or above.

[0056] As a further improvement of the present application,

[0057] The solid solution heat treatment is performed at a temperature range of 950-1150 DEG C.

[0058] As a further improvement of the present application,

[0059] The temperature range of the solid solution heat treatment is 980-1100 DEG C.

[0060] As a further improvement of the present application,

[0061] The precision steel strip can be thinnest rolled to 0.01 mm: 20-roller rolling mill is adopted, the rolling deformation is less than or equal to 80%, the working roller roughness is 0.1 mu m; according to the thickness of the raw material, the target thickness can be rolled through multiple rolling processes, and pure hydrogen reduction annealing is performed between the rolling processes, and the annealing temperature is 1020-1050 DEG C.

[0062] The precision stainless steel for semiconductor and consumer electronics and the preparation method thereof have the following beneficial effects:

[0063] 1. The chemical composition and the role of main chemical elements of the present application

[0064] Chemical composition (mass percent): C: 0.003-0.010%, Si: 0.15-0.30%, Cr: 16.5-17.0%, Ni: 14.5-15.0%, Mo: 2.2-2.8%, Mn: 0.10-0.40%, Cu: 0.08-0.25%, N: 0.001-0.015%, O: 0.003-0.0015%, Al: 0.001-0.01%, S: 0.006-0.01%, P: 0.015-0.030%, Ca: 0.005-0.02%, Nb≤0.05%, Ti≤0.02%, Se≤0.02%, and the above elements simultaneously satisfy the following relationship: 1.25≤(Cr+Mo+1.5Si) / (30N+30C+0.25Cu+0.5Mn+Ni)≤1.33, Ca:Al≥2.0, Si:Al≥25, and the balance is iron and unavoidable impurities;

[0065] The material of the above composition system has a full austenite structure, and sulfides (A type), oxides (B type), silicates (C type), and spherical oxides (D type) are all ≤1.0 grade.

[0066] Carbon elements can promote the formation and stabilization of austenite phase. However, when the carbon content exceeds a certain threshold, it will promote the precipitation of chromium-rich carbides, which is not conducive to its corrosion resistance. The carbon content in the steel of the present application is designed to be 0.003%-0.010%, which ensures that the annealed state is full austenite phase and no carbides are precipitated at the grain boundaries.

[0067] Silicon is mainly added to steel as a deoxidizer, and silicon also plays a solid solution strengthening role. However, the ductility of steel decreases with high silicon content, and considering the machinability of stainless steel, the content of silicon is 0.15-0.30%.

[0068] Manganese is both a deoxidizing element and an austenite stabilizing element, but it is not conducive to corrosion resistance, especially the sulfides of Mn affect corrosion resistance, and the design of manganese content is 0.10-0.40%.

[0069] Chromium is the main element to ensure the corrosion resistance of stainless steel, but chromium is an important ferrite element, and high chromium will cause the appearance of ferrite phase in stainless steel, and the design of chromium content is 16.5-17.0%.

[0070] Molybdenum is an important element to improve corrosion resistance, but molybdenum also promotes the formation of ferrite phase and high content of molybdenum easily leads to the precipitation of intermetallic phase, affecting the corrosion resistance, and the design of molybdenum content is 2.2-2.8%.

[0071] Nickel is a main austenite stabilizing element, which is beneficial to obtain excellent plasticity and toughness and good processing performance, but the increase of content significantly increases the cost, and the design of nickel content in the steel of the present application is 14.5-15.0%.

[0072] Copper in austenitic stainless steel is multifaceted, including improving cold workability, reducing the tendency of cold work hardening. But the copper content is too high to affect the hot workability, the design of copper content is 0.08~0.25%.

[0073] Nitrogen is an austenite phase forming element, which can stabilize the austenite phase, but in the semiconductor environment, nitrogen element is required to be controlled in a lower range, and the nitrogen content is designed to be 0.001~0.015%.

[0074] The content of a plurality of elements is comprehensively controlled to meet 1.25≤(Cr+Mo+1.5Si) / (30N+30C+0.25Cu+0.5Mn+Ni)≤1.33, so as to ensure that the material has a full austenite structure after solid solution treatment.

[0075] Oxygen, sulfur and phosphorus are impurity elements brought by raw materials in the smelting process or into the molten steel, which have adverse effects on corrosion resistance, but it is difficult to completely remove and the cost is high, so the design is O:0.003~0.0015%, S:0.006~0.02%, P:0.015~0.030%, and the content is controlled at a low level to ensure that the material has high purity and corrosion resistance.

[0076] Aluminum and calcium are deoxidation products and are the main elements of steel slag and molten steel interaction in the smelting process, and hard inclusions are easily formed when the Al content is high, so the Al content is controlled to be 0.001~0.01%, and the Ca content is controlled to be 0.005~0.02%.

[0077] The present application preferentially selects silicon deoxidation or silicon-aluminum composite deoxidation, and then aluminum deoxidation, so the design is Si:Al≥25. For aluminum-silicon composite deoxidization or aluminum deoxidization, calcium treatment can modify the hard inclusions containing aluminum, but the appropriate ratio needs to be maintained, and the present application designs Ca:Al≥2.0.

[0078] Niobium, titanium and selenium can refine the grains, but when the content is high, precipitates are formed, which adversely affect the quality of the subsequent precision strip, so the content is controlled to be Nb≤0.05%, Ti≤0.02%, Se≤0.02%.

[0079] 2, the manufacturing method and key process of the present application

[0080] The formula of the present application can be prepared by two preparation processes, respectively, to prepare precision stainless steel materials for ultra-purity semiconductor and consumer electronics and high-purity semiconductor stainless steel materials:

[0081] 1) high-purity metal batching → vacuum induction melting → casting → forging → vacuum arc melting → solidification → forging or rolling (abbreviated as V / V process), the V / V process can prepare precision stainless steel materials for ultra-purity semiconductor and consumer electronics;

[0082] 2) High-purity metal ingredients → vacuum induction melting → casting → forging or rolling (referred to as V process); the V process can produce high-purity semiconductor stainless steel materials.

[0083] 3) The billet or continuous casting billet is heated in the temperature range of 1100-1250℃, forged or rolled at above 900℃, and then solution heat treated in the temperature range of 950-1150℃. This ensures that the billet or continuous casting billet has low high-temperature strength, low resistance to forging or rolling deformation, and high high-temperature plasticity. The final forging or final rolling temperature is maintained above 900℃, which can partially eliminate work hardening.

[0084] 4) Solution heat treatment at a relatively high temperature range of 980-1100°C allows the hot-rolled deformed structure to fully recover and recrystallize. The carbides and nitrides precipitated during rolling are completely dissolved, resulting in a softened, fully austenitic structure. Precision cold working of thin strip uses a 20-roll mill with a rolling deformation of ≤80% and a work roll roughness of 0.1μm. This allows for the production of products with a maximum thickness of 0.01mm and a high surface finish. Depending on the stock thickness, multiple rolling passes are used to reach the target thickness, with pure hydrogen reduction annealing between passes at 1020-1050°C.

[0085] 3. The precision stainless steel for semiconductors and consumer electronics and its manufacturing method proposed in this invention have a reasonable chemical composition range, a fully austenitic structure with good plasticity, and inclusions of sulfides (Class A), oxides (Class B), silicates (Class C), and spherical oxides (Class D) are all ≤0.5. Materials prepared using the ultra-pure process have Class A, B, and C inclusions of 0, and Class D inclusions of ≤0.5. The material can be rolled to a minimum of 0.01 mm without holes or warping. The material has a yield strength Rp0.2 value of ≥175 MPa, a tensile strength Rm value of ≥480 MPa, and an elongation A50 of ≥40%. Precision strip can be as thin as 0.01 mm, meeting the requirements of semiconductor industry equipment and consumer electronic components. Through the rational matching of chemical elements, the material has excellent corrosion and oxidation resistance, making it suitable for semiconductor equipment and consumer electronic components.

[0086] 4. The semiconductor-grade and high-purity stainless steel and its manufacturing method proposed in the present invention strictly control the composition, especially inclusion elements such as S and O. The molten steel is purified and inclusions are removed through a V / V duplex process or a V process. In particular, the special elements Al, Ca, and Mn are controlled to ensure appropriate ratios, and hard inclusions are modified to ensure that the material has ultra-high purity or high purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Figure 1 This is the metallographic structure diagram of Example A of the precision stainless steel for semiconductors and consumer electronics of the present invention.

[0088] Figure 2 Figure. Inclusion analysis of Example A for the precision stainless steel for semiconductor and consumer electronics (Class D fine 0.5, the rest 0). DETAILED DESCRIPTION

[0089] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described below in combination with examples and drawings:

[0090] A stainless steel for semiconductor industry and a manufacturing method thereof belong to the field of material technology. The stainless steel has the following chemical composition (mass percentage %): C: 0.003-0.010%, Si: 0.15-0.30%, Cr: 16.5-17.0%, Ni: 14.5-15.0%, Mo: 2.2-2.8%, Mn: 0.10-0.40%, Cu: 0.08-0.25%, N: 0.001-0.015%, O: 0.003-0.0015%, Al: 0.001-0.01%, S: 0.006-0.01%, P: 0.015-0.030%, Ca: 0.005-0.02%, Nb≤0.05%, Ti≤0.02%, Se≤0.02%, the balance being iron and unavoidable impurities.

[0091] The above elements also need to satisfy the following relationships: 1.25≤(Cr+Mo+1.5Si) / (30N+30C+0.25Cu+0.5Mn+Ni)≤1.33, Ca:Al≥2.0, Si:Al≥25, the balance being iron and unavoidable impurities.

[0092] The precision stainless steel material for semiconductor and consumer electronics and the high-purity stainless steel material for semiconductor are prepared by the above-mentioned formula of the stainless steel for semiconductor industry. The preparation method of the austenitic stainless steel is as follows:

[0093] High-purity metal batching→ vacuum induction melting→ casting→ forging→ vacuum arc melting→ solidification→ forging or rolling (referred to as V / V process)

[0094] High-purity metal batching→ vacuum induction melting→ casting→ forging or rolling (referred to as V process).

[0095] By V / V process or V process smelting, the composition, especially S, O and other inclusion elements are strictly controlled, the proper proportion of special elements Al, Ca and Mn is ensured, especially the V / V double process or V process purifies the molten steel, removes inclusions and modifies hard inclusions, so as to ensure that the material has ultra-high purity or high purity, and meets the requirements of precision stainless steel for semiconductor and consumer electronics. The precision thin strip is cold processed by using a 20-roller mill, the deformation amount of rolling range is less than or equal to 80%, the work roll roughness is 0.1 μm, the product with a limit thickness of 0.01 mm can be produced and has high surface and high flatness; according to the thickness of the raw material, the target thickness can be rolled by multiple rolling ranges, and the pure hydrogen reduction annealing is carried out between the rolling ranges, and the annealing temperature is 1020-1050 ℃.

[0096] The above formula material has full austenitic structure, and the four types of inclusions, i.e. sulfide (A type), oxide (B type), silicate (C type) and spherical oxide (D type) are all less than or equal to 0.5 level, the A, B and C type inclusions of the material prepared by the ultra-pure process are 0 level, and the D type inclusion is less than or equal to 0.5 level. The yield strength Rp0.2 value of the prepared material is greater than or equal to 175 MPa, the tensile strength Rm value is greater than or equal to 480 MPa, and the elongation A50 is greater than or equal to 40%, which can meet the requirements of the semiconductor and consumer electronics industry.

[0097] Embodiment

[0098] Embodiments A-J are prepared according to the above formula and process steps of precision stainless steel for semiconductor and consumer electronics, and are rolled to 0.05 mm by using a 20-roller precision mill, and the annealing temperature is 1020 ℃. The specific formula of embodiments A-J is shown in Table 1, the specific process and test results are shown in Table 2:

[0099]

[0100]

[0101]

[0102] Embodiments A-J of the present application are shown in Tables 1 and 2. As shown in the tables, the material has full austenitic structure (see the attached Figure 1 ), the yield strength Rp 0.2 of the finished product is greater than or equal to 240 MPa, the elongation A 50≥45%. Strict control is exercised over the composition, especially inclusion elements such as S and O. The molten steel is purified and inclusions are removed through the V / V dual process or the V process. In particular, the special elements Al, Ca, and Mn are controlled to ensure an appropriate proportion, and the hard inclusions are modified so that the material has ultra-high purity or high purity. Through a large number of experiments, it was found that the V / V dual process and composition design can stably control the three types of inclusions A, B, and C to level 0, and type D to level 0 or level 0.5, with ultra-high purity or V process; the combination of V process and composition design can control four types of inclusions to ≤ level 0.5. Comparative Example 1 is 316L with conventional process and composition ratio, with inclusions of level 1.5 for types A to C and level 2.0 for type D, which cannot meet the requirements of precision plates and strips for semiconductors and consumer electronics. Comparative Example 2 does not specifically control the Al content, reaching 0.015%. The inclusion rating is Class B 1.0 and Class D 2.0. In particular, Class B hard inclusions can easily cause defects such as holes and warping during ultra-thin precision strip rolling. Comparative Example 3 does not control the Al content and Ca:Al ratio. Although the V / V process is used, the inclusion rating results are Class B 1.0 and Class D 1.0, which are lower than the examples. Comparative Example 4 increases the Ni content to 18%, while controlling the Al content, Ca:Al ratio, and Si:Al ratio. The results show that the inclusion rating is Class 0, which is comparable to Examples C and F. However, the increase in Ni content significantly increases the cost. Comparative Example 5 designs a composition system with a C content of 0.05% and a S content of 0.05%. The inclusion rating is Class A 1.0 and Class D 0.5. The sulfide inclusion content increases, and a small amount of carbide precipitates at the grain boundaries, resulting in a decrease in corrosion resistance. Based on a large number of experiments, we have selected an ultra-pure stainless steel precision strip for semiconductors and consumer electronics and its preparation method, composition system and preparation process. The composition, especially inclusion elements such as S and O, are strictly controlled. The V / V double process or V process is used to purify the molten steel and remove inclusions. In particular, the special elements Al, Ca, and Mn are controlled to ensure the appropriate proportion relationship, and the hard inclusions are modified. The material has ultra-high purity or high purity.

[0103] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent transformations made using the present invention are within the scope of patent protection of the present invention.

Claims

1. A precision stainless steel for semiconductors and consumer electronics, characterized in that: The composition of the precision stainless steel for semiconductors and consumer electronics includes the following components in percentage by mass: C：0.003～0.010％； Si: 0.15-0.30%; Cr:16.5～17.0％； Ni: 14.5~15.0%; Mo: 2.2~2.8%; Mn: 0.10~0.40%; Cu: 0.08~0.25%; N:0.001～0.015％； O:0.003～0.0015％； Al:0.001～0.01％； S：0.006～0.01％； P：0.015～0.030％； Ca: 0.005~0.02%; Nb≤0.05%; Ti≤0.02%; Se≤0.02%; The rest is iron and inevitable impurity elements.

2. The precision stainless steel for semiconductors and consumer electronics according to claim 1, characterized in that: The elements in precision stainless steel for semiconductors and consumer electronics must simultaneously satisfy the following relationship: 1.25≤(Cr+Mo+1.5Si) / (30N+30C+0.25Cu+0.5Mn+Ni)≤1.33; Ca:Al≥2.0; Si:Al≥25.

3. The precision stainless steel for semiconductors and consumer electronics according to claim 1, characterized in that: The four types of inclusions in the precision stainless steel for semiconductors and consumer electronics, namely sulfides (Type A), oxides (Type B), silicates (Type C) and spherical oxides (Type D), are all ≤ level 0.

5. The materials prepared by the ultra-pure process have Class A, B and C inclusions of level 0 and Class D inclusions of ≤ level 0.

5. The material yield strength Rp0.2 value is ≥175MPa, the tensile strength Rm value is ≥480MPa, and the elongation A50 is ≥40%.

4. The precision stainless steel for semiconductors and consumer electronics according to claim 1, characterized in that: The material is suitable for precision stainless steel components used in semiconductor equipment and consumer electronics.

5. A method for preparing precision stainless steel for semiconductors and consumer electronics, characterized in that: High-purity stainless steel for semiconductors includes the following preparation steps: The metal batch of the precision stainless steel for semiconductors and consumer electronics according to any one of claims 1 or 2 → vacuum induction melting → casting → forging → vacuum arc melting → solidification → forging or rolling; After the above steps, high-purity stainless steel for semiconductors is obtained; or Ultra-pure stainless steel for semiconductors includes the following preparation steps: The metal batch of precision stainless steel for semiconductors and consumer electronics according to any one of claims 1 or 2 → vacuum induction melting → casting → forging or rolling; Ultra-pure stainless steel for semiconductors is obtained through the above steps.

6. The method for preparing precision stainless steel for semiconductors and consumer electronics according to claim 5, characterized in that: The steel billet or continuous casting billet is heated within a temperature range of 1100-1250°C.

7. The method for preparing precision stainless steel for semiconductors and consumer electronics according to claim 5, characterized in that: Forging or rolling is completed at above 900℃.

8. The method for preparing precision stainless steel for semiconductors and consumer electronics according to claim 5, characterized in that: Solution heat treatment is carried out in the temperature range of 950-1150°C.

9. The method for preparing precision stainless steel for semiconductors and consumer electronics according to claim 5, characterized in that: Cold rolling adopts 20-roll precision rolling mill, and the thinnest rolling can be as thin as 0.01mm without holes and warping. Cold rolling can adopt multiple rolling processes, and the temperature range of intermediate and final annealing treatment is: 1020 ~ 1050℃.

Images