Dry etching method for laser modification and bombardment by means of metal glass microparticles

Abstract

The invention relates to a laser modification and metal glass microparticle bombardment dry etching method, which comprises the following steps of: firing laser on a substrate to modify and weaken the substrate into a laser modification area; and bombarding the laser modified area by metal glass microparticles to form a vertical through hole or a concave hole or structure with a certain inclination angle.

Description

Technical Field

[0001] This invention relates to a dry etching method that uses laser-modified materials and bombardment with metallic glass microparticles. Background Technology

[0002] Dry or wet etching has been widely used for etching semiconductor wafers, glass, ceramic substrates, optical components, microelectromechanical systems (MEMS), microstructures, etc.

[0003] Among them, such as Figures 1-3 The image shows a laser-assisted wet etching method. The glass substrate G is first modified by laser L through the modification region M, thus weakening the glass substrate. Figure 1 Then, hydrofluoric acid etching solution A is used to etch the substrate G to form a V-shaped, gradually angled concave hole H. Figure 2 As shown. The etching solution continues to penetrate and corrode away the substrate material, such as... Figure 3 As shown, a narrow V-shaped through hole is formed for subsequent processing.

[0004] However, this existing etching method has the following drawbacks: Because the etching solution gradually erodes and removes substrate material by tapering into the substrate at an angle, when forming... Figure 3 After the upper and lower through holes are filled as shown, a "waist" is formed at the narrow V-shaped opening (like the waist of a human body), which is not conducive to subsequent processes.

[0005] The tilt angle is actually related to the concentration of the etching solution; as the concentration increases, the tilt angle also increases. The concentration of the etching solution is also related to the etching rate; the higher the concentration, the faster the etching rate. In other words, when we want to increase the etching speed by increasing the etching solution concentration to improve production efficiency, the increased concentration also relatively increases the tilt angle, which is extremely disadvantageous for processes requiring a small tilt angle. Therefore, the control of the etching solution concentration is closely related to the etching rate and the size of the etching tilt angle, increasing the complexity of controlling many operational variables in the process.

[0006] When we want to etch a vertical through hole (i.e., remove) Figure 3 In cases involving a V-shaped profile, as mentioned earlier, existing wet etching methods often struggle to achieve a single, rapid, and direct etching of vertical cylindrical holes or other multi-faceted through-holes due to the angle of inclination. If one wishes to... Figure 3 Further processing the "waist" V shown to create a vertical through-hole is a complex and costly undertaking, and therefore unwise. Thus, wet etching has limitations on the desired through-hole shape or structure and is not widely applicable.

[0007] like Figure 2As shown, the volume is reduced at the bottom or deep part of the V-shaped etch hole, making it difficult for the etchant to flow deep. The residue after etching also accumulates here, forming a barrier between the etchant and the substrate, which greatly reduces the etching rate and reproduces its shortcomings.

[0008] The hydrofluoric acid used is a toxic liquid that is harmful to the human body, and the disposal of the waste liquid will cause environmental problems, which also shows its disadvantages. Summary of the Invention

[0009] The purpose of this invention is to provide a dry etching method that uses laser modification and bombardment with metal glass microparticles. This method involves first selectively modifying and weakening the substrate with a laser, and then bombarding the modified area with metal glass microparticles to drill holes or form structures on the substrate.

[0010] The present invention employs a dry etching method involving laser modification and bombardment with metal glass microparticles. A laser is used to burn the substrate to modify and weaken it, creating a laser-modified region. Metal glass microparticles are then used to bombard the laser-modified region to form a vertical through-hole or a concave hole or structure with a certain tilt angle.

[0011] In some embodiments, the particle size of the metallic glass microparticles is equal to or less than 20 micrometers.

[0012] In some embodiments, the metallic glass microparticles are bombarded on the substrate by a spray gun using a driving gas at a pressure between 1 and 10 Bar and a flow rate equal to or less than 200 meters per second.

[0013] The desirable aspects of the present invention will become clear from the following description in conjunction with the accompanying drawings. Attached Figure Description

[0014] Figure 1 It is the starting step of the existing wet etching method.

[0015] Figure 2 It is the continuation of existing etching methods Figure 1 The subsequent etching pattern.

[0016] Figure 3 This is a schematic diagram of a conventional etching method for forming through-holes.

[0017] Figure 4 This is the starting step of the etching process in this invention.

[0018] Figure 5 This is the continuation of the present invention Figure 4 Further etching diagram.

[0019] Figure 6 This is a schematic diagram of the etching process used in this invention to form a through-hole at approximately 90 degrees.

[0020] Explanation of markings in the diagram: 1...substrate; G...glass; 11...laser-modified zone; L...laser; 12……Concave holes; A……Etching solution; 13...Vertical through hole; M...Modified zone; 2...laser; H...concave hole; 3……metallic glass microparticles; V……narrow opening. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention. See also Figures 4-6 The etching step of the present invention includes: On substrate 1, laser 2 is used to burn the modified region 11 of the substrate, causing the material to deteriorate and weaken, making it easier for subsequent bombardment by metal glass microparticles (such as...). Figure 4 (As shown). Because the etch rate of the modified and weakened areas is higher than that of the unmodified areas when bombarded, selective dry etching can be performed. In addition to glass, the substrate 1 also includes: silicon wafers, quartz, silicon nitride, silicon carbide, aluminum oxide, aluminum nitride, gallium nitride, zirconium oxide, etc.

[0022] Next, as Figure 5 As shown, metallic glass microparticles 3 are kinetic-energy bombarded with the modified region 11 of the substrate to create a concave hole 12, the sidewall of which can be approximately 90 degrees. The metallic glass microparticles used in this invention have the following characteristics: ultra-high hardness (higher than the hardness of the substrate), high sphericity, smooth surface, and small particle size (equal to or smaller than 20 micrometers), so as not to cause cracks or breakage when bombarding the substrate. Furthermore, the surface roughness Rz of the metallic glass microparticles is less than 0.1 micrometers, without edges, pits or sharp corners, and the hardness of the microparticles must be higher than the hardness of the substrate being processed.

[0023] Continue Figure 5 The uncut modified region 11 was further bombarded with metallic glass microparticles 3, eventually forming a dry-etched vertical through-hole 13 at approximately 90 degrees, as shown. Figure 6 As shown.

[0024] This invention can also be used to directly bombard metal glass microparticles to form through holes after laser modification, i.e. Figure 4 Directly to Figure 6 .

[0025] Of course, in addition to 90-degree vertical through holes, different tilt angles can also be formed by bombarding the sidewalls of the recessed holes in the substrate with metal glass microparticles.

[0026] This invention is applied to etching silicon wafers. Without laser modification, even with bombardment by metal glass microparticles, the etching depth is only 65.74 micrometers. However, after deep laser ablation, bombardment by metal glass microparticles can achieve a depth of 398.45 micrometers. It can be seen that this invention first modifies and weakens the substrate with laser, and then bombards it with metal glass microparticles, which can etch very deep, even through the thickness of the substrate, to form through-holes. This is difficult to achieve with existing wet etching.

[0027] The metallic glass microparticles of this invention possess ultra-high hardness, enabling them to bombard and etch hard substrates, such as silicon carbide and silicon nitride, with ease. Furthermore, due to their high sphericity, smooth surface, and small particle size, they will not cause cracks or fractures in the substrate.

[0028] The driving gas for bombardment of metallic glass microparticles in this invention can be air, nitrogen, argon, etc., and the bombardment pressure is between 1 and 10 Bar (kg / cm²). 2 The driving gas velocity is 200 meters per second (or less) until it is ejected from the spray gun. Of course, the variables in actual operation depend on the process requirements.

[0029] In addition to etching vertical through holes, this invention can adjust the incident angle of the bombardment to enhance the etching of the sidewalls of concave holes. Therefore, it can be processed laterally to the desired depth, and the tilt angle of the bombarded sidewalls can be adjusted at will. Its process control is easy and convenient.

[0030] The metal glass microparticles of the present invention bombard the substrate at high speed and instantaneously, which is a physical or mechanical operation of rapid cutting and polishing, rather than the existing wet etching method, which has to take into account many interrelated variables such as the concentration of the etching solution and the adjustment of the tilt angle, and is time-consuming and labor-intensive.

[0031] The advantages of this invention over prior art are as follows: Vertical through holes, or other recessed holes and structures with various tilt angles, can be easily etched, and the process is simple.

[0032] The operation of this invention is characterized by convenient mechanical or physical control, which is superior to the complex chemical manipulation of existing wet etching processes.

[0033] The metallic glass microparticles of this invention are recyclable and reusable, avoiding resource waste and eliminating the thorny problem of waste liquid treatment associated with existing etching solutions. This invention is truly environmentally friendly. Furthermore, this invention does not require the use of toxic etching solutions, significantly contributing to industrial safety and hygiene.

[0034] This invention substantially improves the yield and reliability of the process, and is superior to existing laser-induced substrate processing processes (which do not bombard with metal glass microparticles), without the absence of the heat-affected zone (HAZ), slag, and via blockage that are common in existing laser processing.

[0035] The preferred embodiments of the present invention may be modified or arranged appropriately without departing from the spirit and scope of the present invention, and the present invention is not limited thereto.

[0036] The substrate of this invention refers to: core substrate, coreless substrate, interposer, interposer containing redistribution layer (RDL), and other substrates, and is widely used in semiconductors, glass, ceramics, optical components, microelectromechanical systems (MEMS), and microstructures.

[0037] The embodiments described above are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention, or reasonable combinations of features and solutions from various embodiments, are all within the scope of protection of the present invention.

Claims

1. A dry etching method of laser modification and bombardment with metal glass microparticles, characterized in that, include: A laser is used to burn the substrate to modify and weaken it, creating a laser-modified region. The laser-modified region is bombarded with metallic glass microparticles to form a vertical through hole or a concave hole or structure with a certain tilt angle.

2. The laser modification and dry etching method by metal glass particle bombardment according to claim 1, wherein The particle size of the metallic glass microparticles is equal to or less than 20 micrometers.

3. The dry etching method of laser modification and bombardment with metallic glass microparticles as described in claim 1, characterized in that, The metallic glass microparticles are bombarded on the substrate by a spray gun using a driving gas at a pressure between 1 and 10 Bar and a flow rate equal to or less than 200 meters per second.

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