Wafer with special-shaped through hole and preparation method thereof

Abstract

The invention discloses a wafer with special-shaped through holes and a preparation method thereof, the wafer comprises a wafer body, the wafer body is provided with a plurality of through holes, the plurality of through holes are formed through laser induction and depth etching, the upper end radius of the plurality of through holes is um-mm, the lower end radius of the plurality of through holes is um-mm, the thickness of the wafer body is. The wafer body is made of glass, quartz or sapphire. Through ingenious design, the stirring rotor is used for regulating and controlling the flow rate of the corrosion solution on the two sides of the glass wafer and controlling the corrosion rate on the two sides, so that the trapezoidal through hole is prepared, and the mode is simple, easy to operate, high in efficiency and good in process controllability.

Description

Technical Field

[0001] The invention relates to the technical field of laser micromachining, and in particular to a wafer with a special-shaped through hole and a preparation method thereof. Background Art

[0002] With the development of the semiconductor industry, glass is increasingly being used in the fields of 3D packaging, display, etc., due to its excellent high-frequency electrical properties, low cost, strong mechanical stability and other application advantages. Through glass via (TGV) technology is one of the most effective technologies for achieving 3D integration and high-performance passive substrates, which can significantly improve the connection transmission efficiency and has advantages in cost and performance.

[0003] At present, one of the methods of forming a through hole in TGV technology is laser induced deep etching (LIDE), which uses pulsed laser to induce local modification of glass, so that the properties and molecular structure of the modified area change, and then uses corrosive liquid to selectively etch. Since the chemical activity of the modified area is stronger, its corrosion rate is much greater than that of the non-modified area, so the corrosive liquid will remove the modified area faster, forming a through hole through the glass substrate.

[0004] After searching, the Chinese invention patents with publication numbers CN118125707A and CN112864026B both use laser induction combined with acid corrosion to obtain glass ports of good quality. However, the hole types prepared by the existing TGV technology are mostly relatively single, with only cylindrical ports such as straight holes and blind holes, which cannot be applied to more complex application scenarios. In contrast, the ports can meet the technical problem of all signal transmission functions.

[0005] The Chinese invention patent with publication number CN114560634 A proposes to use laser combined with ultrasonic guided wet etching to process special-shaped glass openings. It uses laser induction with a single-sided mask and laser rotary cutting, and uses high-precision ultrasonic equipment to etch to obtain a trapezoidal opening. The process is relatively complicated and the controllability of the taper is unknown. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings existing in the prior art, and a wafer with special-shaped through holes and a preparation method thereof are proposed. Through ingenious design, a stirring rotor is used to regulate the flow rate of the etching solution on both sides of the glass wafer, and the etching rate on both sides is controlled, thereby preparing a trapezoidal through hole. This method is simple and easy to operate, has high efficiency, and good process controllability.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A wafer with special-shaped through holes comprises a wafer body, wherein the wafer body is provided with a plurality of through openings, wherein the plurality of through openings are formed by induced laser and deep etching, wherein the upper end radius of the plurality of through openings is 20um-2mm, the lower end radius of the plurality of through openings is 50um-3mm, the thickness of the wafer body is 0.2-5mm, and the material of the wafer body is glass, quartz or sapphire.

[0009] Preferably, the laser source of the induced laser is a picosecond or femtosecond laser, the solution used for deep etching is an alkaline corrosive solution or an acidic corrosive solution, the alkaline corrosive solution is any corrosive material based on hydroxide, and the acidic corrosive solution is hydrofluoric acid, hydrochloric acid, sulfuric acid or a mixture thereof.

[0010] A method for preparing a wafer with a special-shaped through hole comprises the following steps:

[0011] S1: irradiating the substrate to be processed with a pulsed laser beam to form a modified line in the substrate to be processed that completely penetrates the substrate from the upper surface of the processed substrate, and laser modifying the substrate to be processed over the entire thickness;

[0012] S2: coating an anti-corrosion protective coating on the upper surface of the processed substrate after the processing in step S1;

[0013] S3: The substrate to be processed after being processed in step S2 is horizontally placed in a corrosion container filled with a corrosion liquid for corrosion processing, thereby forming a through opening with the position of the modified line as the center in the substrate to be processed.

[0014] Preferably, the corrosion container is specially designed according to the outer dimensions of the substrate to be processed, that is, the upper half of the corrosion container is larger than the substrate to be processed, and the lower half is smaller than the substrate to be processed. The outer shape is stepped, and the substrate to be processed is supported by the stepped structure in the middle of the corrosion container.

[0015] Preferably, the bottom of the corrosion container is provided with a heating device to heat the corrosion liquid.

[0016] Preferably, there is also a magnetic stirring device at the bottom of the corrosion container, and the magnetic stirring device is mainly composed of a motor, a magnetic controller and a magnetic stirring rotor. The basic working principle of the magnetic stirring device is to utilize the principle of like charges repel each other and unlike charges attract each other in the magnetic field, and to rotate the magnetic stirrer by continuously changing the polarity at both ends of the base, thereby driving the stirring of the corrosion liquid.

[0017] Preferably, the magnetic stirring device can adjust the flow rate of the etching liquid on the upper surface and the lower surface of the substrate to be processed, thereby adjusting the etching rate.

[0018] The present invention has the following beneficial effects:

[0019] The present invention only needs one laser modification and one corrosion to complete the manufacture of truncated cone microholes, without other processes and repeated processing, with a simple process flow, low processing cost, and high controllability of the obtained hole type, which ensures the consistency and processing quality of the truncated cone microhole processing, and provides more choices and usage scenarios for three-dimensional integrated packaging and atomization structures. In actual operation, the hole type and aperture can be customized according to demand, so that it is suitable for more application scenarios, such as optical fiber fixing plates, optical communications, radio frequency modules, optoelectronic system integration, MEMS packaging, consumer electronics, electronic gas amplifiers, medical devices, atomizers and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A cross-sectional schematic diagram of a comparative example of a glass substrate in a wafer with a special-shaped through hole proposed by the present invention;

[0021] Figure 2 is a cross-sectional schematic diagram of the glass substrate in Example 2;

[0022] Figure 3 is a cross-sectional schematic diagram of the glass substrate in Example 4;

[0023] Figure 4 The present invention is a flow chart of a method for preparing a wafer with special-shaped through holes.

[0024] In the figure: 1 wafer body, 2 opening. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0026] Reference Figure 1-Figure 3 A wafer with a special-shaped through hole comprises a wafer body 1, on which a plurality of through holes 2 are arranged, the plurality of through holes 2 are formed by induced laser and deep etching, the upper end radius of the plurality of through holes 2 is 20um-2mm, the lower end radius of the plurality of through holes 2 is 50um-3mm, the thickness of the wafer body 1 is 0.2-5mm, the material of the wafer body 1 is glass, quartz or sapphire, the laser source of the induced laser is a picosecond or femtosecond laser to increase the peak power and facilitate the formation of the through hole 2, the modification of the pulsed laser on the glass substrate can be laser single-point modification, or it can be circle-modified by controlling the relative movement of the light beam and the glass position, the solution used for deep etching is an alkaline corrosive solution or an acidic corrosive solution, the alkaline corrosive solution is any corrosive material based on hydroxide, and the acidic corrosive solution is hydrofluoric acid, hydrochloric acid, sulfuric acid or a mixture thereof.

[0027] Reference Figure 4 , a method for preparing a wafer with a special-shaped through hole, comprising the following steps:

[0028] S1: Use a pulsed laser beam to irradiate the substrate to be processed, and form a modified line in the substrate to be processed that completely penetrates the substrate from the upper surface of the processed substrate, and perform laser modification on the substrate to be processed over the entire thickness. The laser beam can be a Bessel beam, and the focal depth of the Bessel beam can cover the entire thickness of the substrate to be processed. The laser beam generates induced absorption in the substrate to be processed, thereby generating a modified line. Take Bessel laser beam processing as an example, in which the laser energy is 30μJ~300μJ, the pulse width is less than 20ps, and the spot diameter is less than 4μm;

[0029] Laser filamentation can also be used. The filamentation effect comes from the dynamic balance between the self-focusing of the laser beam caused by the optical Kerr effect and the plasma defocusing produced by weak ionization, forming a linear focused light spot of a certain length that propagates forward, generating induced absorption in the substrate to be processed, and producing a modified line extending from the upper surface to the lower surface.

[0030] At the same time, a laser beam can be used to irradiate the upper surface of the substrate to be processed, and the focal point of the beam can be gradually moved toward the lower surface in a direction perpendicular to the upper surface, thereby generating a modified line extending from the upper surface to the lower surface.

[0031] S2: coating an anti-corrosion protective coating on the upper surface of the processed substrate after the processing in step S1;

[0032] S3: Place the substrate to be processed after the processing in step S2 horizontally in a corrosion container filled with corrosion liquid for corrosion processing, so as to form a through opening 2 centered at the position of the modified line in the substrate to be processed, and the upper surface and lower surface of the substrate to be processed correspond to the upper half and lower half of the corrosion container respectively.

[0033] Among them, the corrosion container is specially designed according to the outer dimensions of the substrate to be processed, that is, the upper part of the corrosion container is larger than the substrate to be processed, and the lower part is smaller than the substrate to be processed. The outer shape is stepped, so that the substrate to be processed can be placed in the corrosion container smoothly, but will not enter the lower part of the container. The substrate to be processed is supported by the stepped structure in the middle position of the corrosion container, so that the exchange of liquids in the upper and lower parts of the container can be blocked to a certain extent. There is a heating device at the bottom of the corrosion container to heat the corrosion liquid.

[0034] Since the etching liquid in the upper part of the container is basically in a static state, a constant etching rate can be maintained under certain etching conditions. The reaction rate of the etching liquid in the lower part is controlled by controlling the rotation speed of the magnetic stirring rotor. Since the upper part of the liquid has a certain pressure on the glass substrate, the liquid has resistance, and the gravity of the substrate to be processed, the glass substrate can basically remain static under the state of liquid stirring, so that the exchange of the upper and lower parts of the container can be cut off to a certain extent, so that the etching rate of the lower part of the etching container is greater than that of the upper part, thereby corroding to form the aperture difference between the upper and lower surfaces of the substrate to be processed.

[0035] Among them, there is also a magnetic stirring device at the bottom of the corrosion container. The magnetic stirring device is mainly composed of a motor, a magnetic controller and a magnetic stirring rotor. The basic working principle of the magnetic stirring device is to utilize the principle of like charges repelling each other and opposite charges attracting each other in the magnetic field. The magnetic stirring bar is rotated by continuously changing the polarity at both ends of the base, thereby driving the stirring of the corrosion liquid. The magnetic stirring device can adjust the flow rate of the corrosion liquid on the upper and lower surfaces of the substrate to be processed, thereby adjusting the corrosion rate. The speed range of the stirring rotor is 100-5000r / min.

[0036] In the process of chemical reaction, the collision between reactants is the prerequisite for the reaction to occur, so ensuring that the reactants can fully contact is one of the key factors to increase the reaction rate. In the process of reactant contact, stirring can reduce the distance between chemical reactants, shorten the reaction time, and thus increase the reaction rate. In addition, stirring can also mix the ions and molecules in the reactants evenly to promote the exchange of various substances required in the reaction process, facilitate the discharge of products, the entry of reactants, eliminate bubbles, etc., and thus increase the reaction rate.

[0037] The acidic etching solution is: HF etching solution with a concentration range of 1% to 49%, or buffered oxide etching solution (BOE) with a ratio of HF: NH4F in the range of 1: 0.1 to 1: 10. The temperature range is 5 to 50°C; the alkaline etching solution is: NaOH solution with a concentration range of 10% to 60%, or KOH solution with a concentration range of 10% to 60%. The temperature range is 70 to 150°C.

[0038] The greater the concentration of the etching solution, the higher the temperature, and the longer the etching time, the more parts of the substrate to be processed are corroded and removed, and the larger the size of the micropores formed. Therefore, the amount of the substrate to be processed that is corroded and removed can be controlled according to the composition of the etching solution, the concentration of the etching solution, the temperature of the etching solution, and the etching time, that is, the aperture of the micropores can be controlled. By controlling the rotation speed of the stirring rotor, the difference in the etching rate between the first surface and the second surface of the substrate to be processed can be controlled, that is, the difference in the size of the micropores between the first surface and the second surface can be controlled. When the aperture of the micropores reaches a preset value, the substrate to be processed is taken out, and the etching can be stopped to obtain truncated cone-shaped micropores. The etching time of the substrate to be processed is usually several hours.

[0039] The functional principle of the present invention can be explained by the following operation mode: taking the processing of quartz glass with a thickness of 0.5 mm as an example, the etching liquid is an HF aqueous solution with a concentration of 3wt%, an etching temperature of 20°C, and an etching time of 3 hours. Among them, stirring control is performed in Examples 1, 2, 3, and 4, and stirring is not performed in Comparative Example 1. The specific parameters and results are shown in Table 1.

[0040] Table 1 Processing parameters and corresponding processing effects

[0041]

[0042]

[0043] From the data in Table 1 and the above analysis, it can be seen that, compared with the comparative example, in the embodiment using stirring etching, the etching hole diameter of the lower surface of the glass is significantly larger than that of the upper surface. And from the data in the table, it can be seen that as the speed of the stirring rotor increases, the reaction rate of the lower half of the etching container is accelerated, so the etching hole diameter of the lower surface of the glass increases accordingly, resulting in an increase in the hole diameter difference between the upper and lower surfaces of the glass, and an increase in the hole taper.

[0044] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A wafer with a special-shaped through hole, comprising a wafer body (1), characterized in that: The wafer body (1) is provided with a plurality of openings (2), the plurality of openings (2) are formed by induced laser and deep etching, the upper end radius of the plurality of openings (2) is 20um-2mm, the lower end radius of the plurality of openings (2) is 50um-3mm, the thickness of the wafer body (1) is 0.2-5mm, and the material of the wafer body (1) is glass, quartz or sapphire.

2. A wafer with a special-shaped through hole according to claim 1, characterized in that: The laser source of the induced laser is a picosecond or femtosecond laser, the solution used for the deep etching is an alkaline corrosive solution or an acidic corrosive solution, the alkaline corrosive solution is any corrosive material based on hydroxide, and the acidic corrosive solution is hydrofluoric acid, hydrochloric acid, sulfuric acid or a mixture thereof.

3. A method for preparing a wafer with a special-shaped through hole, characterized in that: The following steps are involved: S1: irradiating the substrate to be processed with a pulsed laser beam to form a modified line in the substrate to be processed that completely penetrates the substrate from the upper surface of the processed substrate, and laser modifying the substrate to be processed over the entire thickness; S2: coating an anti-corrosion protective coating on the upper surface of the processed substrate after the processing in step S1; S3: The substrate to be processed after being processed in step S2 is horizontally placed in a corrosion container filled with a corrosion liquid for corrosion processing, thereby forming a through opening (2) with the position of the modified line as the center in the substrate to be processed.

4. The method for preparing a wafer with a special-shaped through hole according to claim 3, characterized in that: The corrosion container is specially designed according to the outer dimensions of the substrate to be processed, that is, the upper half of the corrosion container is larger than the substrate to be processed, and the lower half is smaller than the substrate to be processed. The outer shape is stepped, and the substrate to be processed is supported by the stepped structure in the middle of the corrosion container.

5. The method for preparing a wafer with a special-shaped through hole according to claim 3, characterized in that: The bottom of the corrosion container is provided with a heating device, which can heat the corrosion liquid.

6. The method for preparing a wafer with a special-shaped through hole according to claim 3, characterized in that: There is also a magnetic stirring device at the bottom of the corrosion container. The magnetic stirring device is mainly composed of a motor, a magnetic controller and a magnetic stirring rotor. The basic working principle of the magnetic stirring device is to utilize the principle that like charges repel each other and unlike charges attract each other in the magnetic field. The magnetic stirring bar is rotated by continuously changing the polarity at both ends of the base, thereby driving the stirring of the corrosion liquid.

7. The method for preparing a wafer with a special-shaped through hole according to claim 6, characterized in that: The magnetic stirring device can adjust the flow rate of the etching liquid on the upper surface and the lower surface of the substrate to be processed, thereby adjusting the etching rate.

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