阅读说明：本技术 一种硅基底薄膜的制备方法 (Preparation method of silicon substrate film ) 是由 郑泉水 柏帆 于 2020-06-28 设计创作，主要内容包括：本发明提供一种硅基底薄膜的制备方法,在硅基底上涂布光刻胶,在涂胶面预先开槽,控制槽的深度和宽度,并利用酸溶液进行平整化处理,待硅基底毛边处理干净之后去胶、清洗、烘干、镀膜,再用薄金刚石刀片,沿着预开槽的中心线将硅基底完全切开,获得完整的硅基底薄膜,边缘无破损。(The invention provides a preparation method of a silicon substrate film, which comprises the steps of coating photoresist on a silicon substrate, pre-grooving a glue coating surface, controlling the depth and the width of a groove, carrying out leveling treatment by using an acid solution, removing glue, cleaning, drying and coating a film after the burrs of the silicon substrate are cleaned, and completely cutting the silicon substrate along the central line of the pre-grooving by using a thin diamond blade to obtain a complete silicon substrate film without damaging the edge.)

1. A preparation method of a silicon substrate film is characterized by comprising the following steps:

(1) cleaning a polishing silicon substrate, and coating photoresist on a polishing surface;

(2) slotting on the pre-coating glue surface of the silicon substrate;

(3) soaking the silicon substrate into an acid solution for leveling treatment;

(4) cleaning silicon substrate slag and rough edges, removing photoresist, cleaning and drying;

(5) coating a film on the surface of the dried silicon substrate;

(6) and cutting the silicon substrate along the central line of the pre-groove to obtain the silicon substrate film.

2. The production method according to claim 1, wherein in the step (2), the silicon substrate is grooved in a crystal direction and a direction perpendicular to the crystal direction to form a plurality of quadrangular blocks; preferably, the length of the side of the quadrilateral block is 4-30 mm.

3. The manufacturing method according to claim 1 or 2, wherein the acid solution for the planarization treatment in the step (3) includes hydrofluoric acid, nitric acid, acetic acid, preferably a mixed solution of the three.

4. A production method according to claims 1 to 3, characterized in that the flattening treatment soaking time in step (3) is 3 to 30 minutes, preferably 5 to 15 minutes, and more preferably 5 minutes.

5. The production method according to claims 1 to 4, wherein the washing in step (1) comprises acid washing, alkali washing, secondary acid washing, and washing with high purity water is performed after each washing.

6. The method of claim 5, wherein the acid wash employs H₂SO₄:H₂O₂Acid solution of 4:1, alkaline washing with H₂O:H₂O₂:NH₄H is adopted for secondary acid cleaning of alkaline solution with OH being 5:1:1₂O:H₂O₂HF-5: 2:1 acid solution.

7. The method of claims 1-6, wherein the grooving in step (2) is performed by using a diamond dicing saw, and the depth of the groove is controlled to be half of the thickness of the silicon substrate and the width is controlled to be 0.5-1.5 mm.

8. The method of claims 1-7, wherein the polished silicon substrate in step (1) is preferably 2 inches, 4 inches, 6 inches, 8 inches, 12 inches in size.

9. The method as claimed in claims 1-8, wherein the photoresist thickness in step (1) is greater than 1 μm, the spin coating speed is 800-4000rpm, and the time is 10-60 s.

10. A method of producing according to claims 1 to 9, wherein the silicon substrate is cut along the center line of the pre-groove in step (6) with a diamond blade having a width of 10 to 100 μm, preferably 50 μm.

Technical Field

The invention relates to the field of solid structure ultra-smoothness, in particular to a method for preparing a small silicon substrate film in the process of preparing ultra-smooth devices in batches.

Background

For a long time, friction and wear problems have been closely related not only to manufacturing, but also directly to energy, environment and health. Statistically, about one third of the world's energy is consumed during friction, and about 80% of machine component failures are caused by wear. The ultra-smooth structure is one of ideal schemes for solving the problem of frictional wear, and the ultra-smooth structure refers to the phenomenon that the friction and the wear between two atomic-level smooth and non-metric contact Van der Waals solid surfaces (such as two-dimensional material surfaces of graphene, molybdenum disulfide and the like) are almost zero. In 2004, the netherlands scientist j.frenken's research group measured the friction of a few nm-sized (total about 100 carbon atoms) graphite sheet stuck on a probe when the crystal face of Highly Oriented Pyrolytic Graphite (HOPG) slides by experimental design, and the first experiment confirmed the existence of nano-scale super lubrication. In 2013, zhengquan professor discovered the ultra-slip phenomenon between hopg (high Oriented pyrolytic graphite) sheet materials for the first time at micron scale, which marks the transition of ultra-slip from basic research to applicable technical research process.

In the process of preparing the ultra-slip device, the preparation of a silicon substrate is often involved, and the preparation of a high-quality small-sized silicon substrate is an important factor influencing the yield because the ultra-slip sheet is small in size. At present, the methods for preparing the miniature silicon substrate film mainly comprise the following two methods: firstly, a large-size silicon wafer is cut into a small-size silicon wafer, and then the small-size silicon wafer is coated with a film, but the method is easily limited by equipment and environment, the preparation process is complicated, and the preparation efficiency is low; secondly, a large-size silicon wafer is coated with a film, and then the large-size silicon wafer is cut into small-size silicon wafers, but the method has the defect that the coating film on the surface of the silicon substrate can be broken due to the action of mechanical force or the silicon substrate is broken, the coating surface can be damaged by generated scraps, and the coating surface is incomplete. In addition, the small-sized silicon wafer prepared by the above two methods has uneven side edges, including side edge burrs, undulations and edge breakages, and the uneven side edges may affect the preparation yield of the ultra-smooth device.

Disclosure of Invention

In order to solve the above problems, the present invention proposes the following solutions: coating photoresist on a silicon substrate, slotting in advance on a glue coating surface, controlling the depth and the width of the slot, carrying out leveling treatment by using an acid solution, removing the glue, cleaning, drying and coating after the burrs of the silicon substrate are completely treated, and completely cutting the silicon substrate along the central line of the slotting by using a thin diamond blade to obtain a complete silicon substrate film without damaging the edge.

Specifically, the invention aims to be realized by the following technical scheme:

(1) cleaning a polishing silicon substrate, and coating photoresist on a polishing surface;

(2) slotting on the pre-gluing surface of the silicon substrate, controlling the depth of the slot to be half of the thickness of the silicon substrate, and preferably controlling the width of the slot to be 0.5-1.5 mm;

(3) soaking the silicon substrate into an acid solution for leveling treatment, wherein the soaking time is within the range of 3-30 minutes;

(4) cleaning silicon substrate slag and rough edges, removing photoresist, cleaning and drying;

(5) coating a film on the surface of the dried silicon substrate;

(6) and completely cutting the silicon substrate along the center line of the pre-groove by using a thin diamond blade to obtain a silicon substrate film.

Further, in the step (2), grooving is performed along the crystal direction of the silicon substrate and the vertical direction of the crystal direction according to the required size, and a plurality of quadrilateral blocks are formed.

Further, the side length of the quadrilateral block is 4-30 mm.

Further, the acid solution for the planarization treatment in step (3) includes hydrofluoric acid, nitric acid, and acetic acid, preferably a mixed solution of the three.

Further, the soaking time of the planarization treatment in the step (3) is preferably 5 to 15 minutes, and more preferably 5 minutes.

Further, the cleaning in the step (1) comprises acid cleaning, alkali cleaning and secondary acid cleaning, and high-purity water is adopted for cleaning after each cleaning; more preferably, the acid washing is performed with H₂SO₄:H₂O₂Acid solution of 4:1, alkaline washing with H₂O:H₂O₂:NH₄H is adopted for secondary acid cleaning of alkaline solution with OH being 5:1:1₂O:H₂O₂Acid solution of HF 5:2:1

Furthermore, the slotting mode in the step (2) is to use a diamond scribing machine to slot on the precoating surface of the polished silicon wafer along the crystal direction of the polished silicon wafer and the vertical direction of the crystal direction, the width of the slot is 0.5-1.5mm, and the depth of the slot is about half of the thickness of the silicon wafer.

Further, the silicon substrates polished in step (1) have dimensions of 2 inches, 4 inches, 6 inches, 8 inches, and 12 inches.

Further, in the step (1), the photoresist thickness is larger than 1 μm, the spin coating speed is 800-.

Further, in the step (6), the silicon substrate is cut along the center line of the pre-groove by using a diamond blade, and the width of the diamond blade is 10-100 μm, and preferably 50 um.

According to the technical scheme, the prepared silicon substrate film is regular in shape, complete in surface and free of edge damage, and the phenomena of side edge burrs, fluctuation, edge breakage and the like caused by cutting in the prior art can be effectively avoided; meanwhile, the complete polished silicon substrate can be used for preparing small silicon substrate films with good batch consistency, the efficiency is high, the quality is good, the large-batch production can be realized, the process requirement is low, and the production cost can be effectively reduced.

Drawings

FIG. 1 illustrates a cross-sectional side view of a prior art silicon substrate thin film structure;

FIG. 2 shows a surface atomic force photo topography of a film of a prior art silicon substrate thin film structure;

FIG. 3 shows a process flow diagram of the present invention;

FIG. 4 illustrates a top view of a silicon substrate slot of the present invention;

FIG. 5 illustrates a partial trenching side view of a silicon substrate of the present invention;

FIG. 6 shows the surface atomic force photo topography of the silicon substrate film prepared by the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The method for producing the silicon substrate film of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 1, the silicon substrate is a thin film structure, the lower portion is a silicon substrate, and the upper portion is a thin film, and the thin film material may be silicon oxide, titanium oxide, silicon nitride, aluminum oxide, or the like. FIG. 2 is a surface atomic force photograph of a film with a conventional silicon substrate film structure, wherein white particles and strip portions are defects on the surface of the sample film.

Fig. 3 shows a process flow of the silicon substrate thin film preparation of the present invention, and a specific embodiment of the present invention is described below in conjunction with the process flow in fig. 3.

Cleaning surface of one-and large-size polished silicon wafer

Sequentially using the volume ratio of H to the surface of the polished silicon wafer₂SO₄:H₂O₂4:1 acid solution, H₂O:H₂O₂:NH₄Basic solution of OH 5:1:1, H₂O:H₂O₂HF ═ 5:2:1 acid solution cleaning. After each solution cleaning process is finished, the silicon wafer is cleaned by ultrapure water, and then the next cleaning process is carried out. And after the silicon wafer is cleaned, the silicon wafer is blown dry by nitrogen and placed in an oven at 120 ℃ for 30min, so that the water is completely removed.

Secondly, coating photoresist

The polished silicon wafer after being cleaned and dried is placed in an HMDS fumigating box, HMDS is fumigated for 10min at 100 ℃, and then photoresist is coated.

Cleaning a turntable of a spin coater with acetone and deionized water, blow-drying with nitrogen, placing into the spin coater, placing the polished silicon wafer with the HMDS on the turntable, and opening vacuum. The AZ4620 photoresist was poured onto the silicon wafer with a beaker covering approximately two-thirds of the area, and then a spin program was run and baked on a hot plate at 120 ℃ for 3 min.

Thirdly, grooving on the surface of the large-size polished silicon wafer according to the required size, wherein the depth of the groove is about half of the thickness of the silicon wafer

And (3) slotting on the gluing surface of the polished silicon wafer along the crystal direction of the polished silicon wafer and the vertical direction of the crystal direction according to the required size of the silicon substrate, wherein the interval between the central lines of the two slots is 10mm, the width of the slot is 1mm, the depth of the slot is half of the thickness of the silicon wafer, and the silicon wafer is divided into a plurality of quadrilateral blocks.

Fourth, planarization treatment

With HF, HNO₃:CH₃Soaking the silicon wafer in the COOH solution for 5 minutes, flattening the side cutting surface of the silicon wafer, and placing the grooved silicon wafer in a volume ratio of HF to HNO₃:CH₃And soaking the silicon wafer in the COOH-1: 3:8 solution for 5 minutes, and then washing the silicon wafer by using deionized water. So as to remove the scraps, burrs and large fluctuation of the side edges generated on the two side edges of the slot in the slot process. In other embodiments, the solution may be a mixture of hydrofluoric acid and hydrogen peroxide (1:2-1:4), a combination of hydrofluoric acid and nitric acid (1:2-1:8), or a combination of hydrofluoric acid, nitric acid, and acetic acid (1:2-8: 3-8). Wherein the mass fraction of the hydrofluoric acid is 40%, the molar concentration is 23mol/L, the mass fraction of the nitric acid is 68%, the molar concentration is 15.2mol/L, the mass fraction of the acetic acid is 36%, the molar concentration is 6.3mol/L, the mass fraction of the hydrogen peroxide is 30%, and the molar concentration is 10 mol/L.

Fifthly, removing glue, cleaning and drying

And (3) soaking the silicon wafer with the side scraps, burrs and undulations removed in acetone to remove photoresist, performing ultrasonic treatment in acetone, alcohol and deionized water for 5min, blow-drying with nitrogen, and placing in a 120 ℃ oven for 30min to completely remove water.

Sixthly, coating film on silicon chip

And carrying out a corresponding film coating process on the processed polished silicon wafer.

Seven, slicing

And cutting the polished silicon wafer plated with the film along the center line of the groove by using a diamond blade with the width of 50 mu m to obtain a large number of silicon substrate film samples with the same structure and quality.

As shown in fig. 6, the atomic force microscope photomicrograph of the surface of the silicon substrate film prepared according to the process of the embodiment shows that the film has regular and complete shape and no damage on the edge, and is obviously superior to the film quality of the prior art.

The above-described embodiments are only preferred embodiments of the present invention, and the present invention is not limited to these embodiments, and other variations should be allowed. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, structures, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Variations that fall within the scope of the independent claims or that can be easily ascertained by one of ordinary skill in the art based on the present invention are within the scope of the present invention.