Method for manufacturing a large-size etching cavity of a semiconductor

Abstract

The application discloses a preparation method of a semiconductor large-size etching cavity, and has the technical scheme as follows: selecting high-purity alumina granulation powder with a net content of 99.99%, a median diameter of 90 microns and a particle size distribution of 80-180 microns for forming; first, a customized rubber sleeve mold is sleeved on a steel mold in an interference fit, and the rubber sleeve mold is fastened on a vibrating platform for powder filling by adopting an uninterrupted vibration and filling mode; after filling is completed, a rubber plug is inserted and sealed by using adhesive tape; then, a vacuum pipe is inserted for vacuumizing, and after the vacuum pipe is pulled out, a sealing pipe is immediately inserted and sealed by using sealing adhesive tape; the formed green body is placed into an isostatic press for pressing; and after the formed green body is inspected in appearance and size, the green body is machined according to a green body drawing; the narrow particle size distribution spherical powder can ensure the filling property and uniformity of the green body and ensure high grain uniformity and compactness.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor, in particular to a preparation method of a semiconductor large-size etching cavity. BACKGROUND

[0002] With the development of China's semiconductor integrated circuit core equipment manufacturing industry, especially in the semiconductor etching equipment, with the continuous improvement of the integration level of integrated circuits and the continuous reduction of feature size, the etching technology faces many new opportunities and challenges. Especially the pollution problem of etching machine cavity material to the wafer in the plasma etching process seriously affects the yield of the wafer. In order to realize high-precision process, it is necessary to use materials with good functional characteristics, and structural ceramic parts with stable structure and accurate size. In order to solve and break through the phenomenon of "neck" in the semiconductor industry, it is necessary to implement localization of key core technologies and parts of semiconductor production equipment. In this process, the preparation method of the semiconductor large-size etching cavity is the research focus.

[0003] For example, the existing Chinese patent with publication number CN110190026B discloses a semiconductor preparation method, which comprises the following steps: providing a semiconductor structure; forming an encapsulation layer on the upper surface of the semiconductor structure; thinning the encapsulation layer from the upper surface of the encapsulation layer; forming a metal seed layer on the upper surface of the encapsulation layer; and pretreating the upper surface of the metal seed layer, wherein the pretreatment comprises the step of treating the upper surface of the metal seed layer with a debonding solution; and forming a photoresist layer on the upper surface of the metal seed layer. The semiconductor preparation method can improve the contact performance of the photoresist layer and the metal seed layer, can form a photoresist layer with uniform thickness on the upper surface of the metal seed layer, and can improve the yield and product performance.

[0004] For another example, the existing Chinese patent with publication number CN106229291A discloses a semiconductor preparation method, which comprises the following steps: providing a substrate; depositing a dielectric layer on the upper surface of the substrate; forming a first protective layer on the dielectric layer at the edge of the substrate, the first protective layer having a first width in the direction from the edge of the substrate to the center of the substrate; forming a contact hole structure in the dielectric layer not covered by the first protective layer; forming a second protective layer on the dielectric layer at the edge of the substrate, the second protective layer having a second width in the direction from the edge of the substrate to the center of the substrate, the second width being greater than the first width; and forming a gate trench in the dielectric layer not covered by the second protective layer. The present application leaves a certain protective layer on the dielectric layer at the edge of the substrate, so that the dielectric layer at the edge of the substrate is protected, and the formation of a defective structure on the dielectric layer at the edge of the substrate is prevented; and the second width is greater than the first width, which further avoids the generation of defects and improves the reliability of the device.

[0005] The above patents have some advantages, but also have some disadvantages, such as: it is difficult to guarantee the density and densification of the crystal grains when producing the semiconductor large-size etching cavity, and the upper arching effect is prone to occur. SUMMARY

[0006] In view of the problems mentioned in the background art, the purpose of the present application is to provide a preparation method of a semiconductor large-size etching cavity to solve the problems mentioned in the background art.

[0007] The above technical purpose of the present application is realized by the following technical scheme:

[0008] The preparation method of the semiconductor large-size etching cavity comprises the following steps:

[0009] A high-purity alumina granulating powder with a narrow particle size distribution of 99.99% net content, a median diameter of 90 μm and a particle size distribution of 80-180 μm is selected for molding; first, the custom-made rubber sleeve mold is sleeved on the steel mold to make it interference fit, and is fastened with a rigid clamp on a vibration platform for powder filling, the filling is performed in an uninterrupted manner by vibrating while filling, after filling is full, a rubber plug is inserted and sealed with adhesive tape, then a vacuum tube is inserted to extract vacuum, after the vacuum tube is pulled out, a sealing tube is immediately inserted and then sealed with sealing tape, the molded green body is placed in an isostatic press for pressing, and after the molded green body is inspected for appearance and size, it is machined according to the green body drawing;

[0010] For the placement of large-shaped parts, the sitting burning method is adopted, the blank body is placed and sintered by adding V-shaped gaskets and thin flat gaskets from below, the horizontal thin gaskets are placed in the hollow sphere to ensure the flatness of the cavity and prevent sintering shrinkage from being blocked, and the overall performance and shape of the blank body are ensured; the large gasket is adjusted and fixed with the hollow sphere to make it in a horizontal state, then the machined V-shaped gasket is placed in the adjusted horizontal state, and the corundum sand is surrounded around the top of each V-shaped gasket to prevent the hollow sphere from sliding off, after the green body is placed and inspected, it is raised into the resistance furnace, the switch is turned on to input the sintering curve and start running;

[0011] The two-step sintering method is selected for normal pressure sintering, the green body after degassing is raised to the highest temperature T1 at a certain heating rate and is appropriately heat preserved, so that the remaining pores of the blank body are in a metastable state, then it is rapidly cooled to T2 for heat preservation, so that the crystal boundary diffusion proceeds normally.

[0012] Preferably, when the powder filling is performed on the vibration platform fastened with the rigid clamp, the filling is performed in an uninterrupted manner by vibrating while filling, and the starting vibration frequency is controlled to be 18 HZ.

[0013] Preferably, when the molded green body is placed in the isostatic press for pressing, the highest pressure is set to 200 MPa, and the pressure is maintained for 360 S.

[0014] Preferably, after filling, the rubber plug is put in and sealed with adhesive tape, then a vacuum tube is inserted to extract vacuum, and the vacuum is maintained at -6mpa for 15min to check for air leakage.

[0015] Preferably, the large gasket is fixed by a φ5mm hollow ball to be in a horizontal state, and then the machined V-shaped gasket is put in to be adjusted to be horizontal.

[0016] Preferably, the hollow ball with a diameter of φ2mm is put in and adjusted to be horizontal around the V-shaped top of each gasket, and then the machined thin gasket is put in the hollow ball in the same way and adjusted to be horizontal.

[0017] Preferably, the green body after the glue is discharged is raised to the highest temperature T1 at a temperature raising rate of 7-10℃ / min and is appropriately heat preserved, and the heat preservation is performed until the density of the green body reaches 75-90% of the theoretical density according to the size of the green body.

[0018] Preferably, when the green body after being fired is detected, the drainage method is used to test the density of the green body, and when the density of the green body is not less than 3.989 / cm3, it indicates that the grain has been completely densified, and the SEM microscopic morphology is used to analyze the grain size to determine whether the green body has been completely close to densification.

[0019] In summary, the present application mainly has the following beneficial effects:

[0020] Firstly, the present application selects the spherical powder with narrow particle size distribution to ensure the filling and uniformity of the green body and ensure the uniform grain growth and high densification.

[0021] Secondly, the present application uses the V-shaped gasket to increase the uniformity of the temperature field in the sintering process of the green body, and effectively increases the densification of the grain uniform growth.

[0022] Thirdly, the present application uses the green body shrinkage to avoid the deformation in the sintering process of the green body, and effectively avoids the upper arching effect.

[0023] Fourthly, the present application uses the two-step sintering method to inhibit the migration and growth of the sintering grain boundary, increase the grain boundary diffusion to discharge the air hole, and obtain a nearly completely dense sintered body.

[0024] Fifthly, the present application uses the drainage method to test the density of the green body 3.989 / cm 3 , which is basically completely densified. The SEM microscopic morphology analysis shows that the grain is small and uniform without air holes, and the green body has been completely close to densification. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The grain diagram of the present application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0027] Embodiment 1

[0028] Reference Figure 1 The preparation method of the semiconductor large-size etching cavity must implement domestication of key core technologies and parts of semiconductor production equipment to solve and break through the phenomenon of strangling China's semiconductor industry. Therefore, we continuously develop and test to prepare domestic substitutes with independent core manufacturing technology and key parts to realize the domestication of key parts. In order to prevent the pollution of impurities and particles to the cavity in the large-size etching process, we select a-99.99% high-purity imported alumina powder for preparation. Since high-purity alumina has the advantages of high purity, low impurity content, high temperature resistance, acid and alkali resistance, corrosion resistance, good chemical stability, small crystal grains, high density, good mechanical properties, good plasma resistance, good dielectric properties and insulation, etc., it is the first choice for preparing etching cavities.

[0029] For the preparation of large size etching cavity, the preparation of powder is the key. In the early stage of preparation, the minimization of powder should be controlled, the uniformity of micro domain and the whole should be maintained, the density of the green body should be ensured, and the corrosion resistance should be increased. For the molding of powder, the morphology and filling performance of powder should be ensured, and the particles should have a certain particle size distribution to ensure high density. Regular sphericity is beneficial to powder filling in each corner, and irregular powder is easy to produce arch bridge effect, which reduces the density of the molded body. Wide particle size distribution is easy to mix large particles, which produces large pores, and too much fine powder is easy to produce hard agglomeration of powder, which reduces the sintering density and also induces abnormal growth of grains. Although wide particle size distribution strengthens the growth of grains in the middle stage of sintering, the densification rate is slower in the later stage of sintering, which will lead to the deterioration of structural performance due to uneven particles, and the sintering density is reduced. Therefore, we choose a content of 99.99%, a median diameter of 90 μm, a narrow particle size distribution of 80-180 μm, and a high purity alumina granulating powder for molding. The customized rubber sleeve mold is sleeved on the steel mold to make it interference fit and is fastened with a rigid clamp on the vibration platform for powder filling. Since the upper filling port is relatively small, in order to ensure the uniformity of the molded body and prevent layering, the filling is carried out in the way of uninterrupted vibration and filling (start vibration frequency 18HZ). After filling is full, the rubber plug is inserted and sealed with adhesive tape, and the vacuum tube is inserted into the vacuum tube. The vacuum is maintained at-6mpa for 15min to check for air leakage. The vacuum tube is pulled out and the sealing tube is inserted immediately and then sealed with sealing tape. The molded green body is put into isostatic pressing for pressing, and the highest pressure is set to 200mpa, and the pressure is maintained for 360s. After checking the appearance and size of the molded green body, the green body is machined according to the green body drawing.

[0030] For the placement of large irregular parts, the original method is to sit and burn. Due to the accumulation of buried burning materials (alumina hollow sphere with poor thermal conductivity), the sintering cannot fix the body and the weight of the body is large, the shape is irregular, etc., which leads to the deformation of the sintered body. In order to ensure that the body does not deform during sintering, the body is placed and sintered by adding V-shaped gasket and thin flat gasket from below. This placement method can avoid deformation and cracking of the body inside and outside during sintering due to temperature gradient, and the hollow sphere placed by horizontal thin gasket can ensure the flatness of the cavity and prevent sintering shrinkage. The body is adjusted and fixed with φ5mm hollow sphere to make it in horizontal state, then the machined V-shaped gasket is put into the adjusted horizontal state (the added V-shaped gasket can promote uniform heating of heat to the inside and outside of the body), and the φ2mm hollow sphere is surrounded by corundum sand (to prevent the hollow sphere from sliding) and adjusted to the horizontal state. Then the machined thin gasket is put into the hollow sphere in the same way and adjusted to the horizontal state. After the green body is placed and checked, it is slowly lifted into the resistance furnace, the switch is turned on, the sintering curve is input, and the operation is started.

[0031] The etching cavity works in a harsh environment, and the cavity must have high density to resist corrosion. In the past, the sintering under normal pressure, especially for large sintered blanks, is a process of mutual competition between densification and grain growth in the later sintering stage. The grain growth is driven by the chemical gradient caused by the size difference between particles, and the grain growth rate is faster than the densification rate, which is easy to appear pores in the grain. In order to ensure the high density of the blank, we choose two-step sintering method for sintering under normal pressure. The two-step sintering method is to refine the grain size to make the blank densification. After the glue is removed, the green body is heated to the highest temperature T1 at a certain heating rate (about 7-10℃ / mim) and is appropriately heat preserved (according to the size of the blank, the density reaches 75-90% of the theoretical density), so that the remaining pores in the blank are in a metastable state, and then the temperature is quickly reduced to T2 (kinetic window) for long time heat preservation. At this time, the grain boundary diffusion proceeds normally, and the grain boundary migration does not occur due to insufficient energy. Through long time heat preservation, the residual pores in the blank are almost completely discharged, and the grain growth is inhibited, so that the blank is close to complete densification, and the corrosion resistance of the material is greatly improved.

[0032] The narrow particle size distribution spherical powder selected in the application can ensure the filling and uniformity of the green body and ensure the uniform grain growth and high densification. The application adopts the method of adding V-shaped gaskets to increase the uniformity of the temperature field in the sintering process of the blank inside and outside, effectively increases the densification of the blank by uniform grain growth. The blank clamping sintering method of the application can avoid the deformation of the blank in the sintering process, and effectively avoid the upper arch effect. The two-step sintering method of the application can inhibit the migration and growth of the sintering grain boundary, increase the grain boundary diffusion to discharge pores, and obtain a nearly completely dense sintered body. The density of the blank is tested by the drainage method, which is 3.989 / cm3, and the blank is basically completely dense. The SEM micro-morphology analysis shows that the grain is small, uniform and pore-free, and the blank is completely close to densification.

[0033] The product sintering curve data is shown in Table 1:

[0034] Table 1

[0035] Segment No. Temperature (°C) Time (min) Remarks Segment No. 1 Room temperature 420 Evaporation of moisture Segment No. 2 100 660 No Segment No. 3 400 180 No Segment No. 4 400 480 No Segment No. 5 600 200 Evolution of organic matter Segment No. 6 600 150 No Segment No. 7 1540-1580 100 Surface diffusion and migration Segment No. 8 1540-1580 15 No Segment No. 9 1470 1700 Grain boundary diffusion and pore evacuation Segment No. 10 1470 300 Cooling Segment No. 11 1100 -121 No

[0036] Although the embodiments of the application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the application, and the scope of the application is defined by the appended claims and their equivalents.

Claims

1. A method for fabricating a semiconductor large-scale etching chamber, characterized in that: It comprises the following steps: The high-purity alumina granulating powder with a net content of 99.99%, a median diameter of 90 μm and a particle size distribution of 80-180 μm is selected for molding; first, the customized rubber sleeve mold is sleeved on the steel mold in an interference fit, and is fastened on the vibration platform with a rigid clamp for powder filling; the filling is performed in an uninterrupted manner by vibration and filling; after the filling is full, the rubber plug is inserted and sealed with adhesive tape; then the vacuum tube is inserted for vacuumizing; after the vacuum tube is pulled out, the sealing tube is immediately inserted and then sealed with sealing tape; the molded green body is placed in an isostatic press for pressing; after the molded green body is inspected in appearance and size, it is machined according to the green body drawing; For the placement of large-sized special-shaped parts, the sitting-burning method is adopted, the blank is placed and sintered by adding V-shaped gaskets and thin flat gaskets from below, the horizontal thin gaskets are placed in the hollow sphere to ensure the flatness of the cavity and prevent sintering shrinkage from being blocked, and the overall performance and shape of the blank are ensured; the large gasket is adjusted and fixed with a φ5mm hollow sphere to make it in a horizontal state, then the machined V-shaped gasket is placed in the adjusted horizontal state, and corundum sand is used to surround the four corners of each V-shaped top to prevent the hollow sphere from sliding off; after the green body is placed and inspected, it is raised into the electric resistance furnace, the switch is turned on to input the sintering curve and start running; When the corundum sand is used to surround the four corners of each V-shaped top to prevent the hollow sphere from sliding off, a φ2 μm hollow sphere is placed and adjusted to a horizontal state, and then the machined thin gasket is placed in the hollow sphere in the same way and adjusted to a horizontal state; The two-step sintering method is selected for normal pressure sintering; the green body after degassing is raised to the highest temperature T1 at a certain heating rate and is appropriately heat preserved, so that the remaining pores of the blank are in a metastable state; then it is rapidly cooled to T2 for heat preservation, so that the grain boundary diffusion proceeds normally.

2. The method of claim 1, wherein: When the green body is placed on the vibration platform with a rigid clamp for powder filling, the filling is performed in an uninterrupted manner by vibration and filling, and the starting vibration frequency is controlled to be 18 Hz.

3. The method of claim 1, wherein the method further comprises: forming a first dielectric layer on the substrate; forming a second dielectric layer on the first dielectric layer; and forming a third dielectric layer on the second dielectric layer. When the molded green body is placed in an isostatic press for pressing, the highest pressure is set to 200 MPa, and the pressure is maintained for 360 seconds.

4. The method of claim 1, wherein: After the filling is full, the rubber plug is inserted and sealed with adhesive tape, and then the vacuum tube is inserted for vacuumizing, so that it is maintained at -6 MPa for 15 min to check for air leakage.

5. The method of claim 1, wherein: The green body after degassing is raised to the highest temperature T1 at a heating rate of 7-10 ℃ / min and is appropriately heat preserved, and the heat preservation is performed until the size and density of the blank reach 75-90% of the theoretical density.

6. The method of claim 1, wherein: When the sintered green body is detected, the drainage method is used to test the density of the blank, and when the density of the tested blank is not less than 3.989 / cm3, it indicates that the grain has been completely densified, and SEM micro-morphology analysis is used to analyze the grain size to determine whether the blank has been completely close to densification.

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