A method for manufacturing X-shaped through hole in glass substrate

Abstract

The present invention discloses a method for making an X-shaped through hole in a glass substrate, and belongs to the field of making through holes in semiconductor devices. A method for making an X-shaped through hole in a glass substrate comprises: S1, making an aluminum mask in the graphic area on the front and back sides of the glass substrate, and exposing the position where the hole needs to be opened on the glass substrate; S2, setting the RF electrode power, etching time, vacuum pressure, and total flow rate of the mixed gas of the plasma etching equipment, and setting the mixing ratio of C4F8, N2, and O2 in the mixed gas; S3, heating the glass substrate by using the plasma etching equipment; S4, etching the front and back sides of the glass substrate simultaneously by using the plasma etching equipment; S5, actively recovering and treating the generated waste gas by using the plasma etching equipment. Using the plasma etching equipment to etch the front and back sides of the glass substrate simultaneously is conducive to the stability of the hole type, simplifies the process flow, improves the etching efficiency, and reduces the cost.

Description

Technical Field

[0001] The invention relates to the field of through-hole manufacturing of semiconductor devices, and more specifically to a method for manufacturing an X-shaped through-hole of a glass substrate. Background Art

[0002] In modern electronic technology, printed circuit boards (PCBs) are the core components of electronic products. Their design and manufacturing processes have a vital impact on the performance and reliability of the entire electronic equipment. The main function of PCBs is to provide electrical connections and mechanical support. Their complexity continues to increase with the demand for miniaturization, functional diversification, and high performance of electronic equipment. Compared with traditional epoxy resin substrates, PCBs using glass substrates have better electrical and mechanical properties, lower dielectric constants, higher signal transmission speeds, and less loss. In order to achieve electrical connections between different circuit layers of glass-based PCBs, through holes need to be opened on the glass substrate. The development and application of through-hole technology is of great significance to improving the performance and manufacturing efficiency of PCBs.

[0003] After searching, the patent document with the existing publication number CN110491831A provides a method for making a through hole and a manufactured device. The method can achieve the through hole of a thick device by etching the front and back sides. And through the bottom structure of the first metal layer, the directionality of the ions in the through hole is changed, so that the side wall of the through hole is smoother, and the control ability of the through hole morphology is improved.

[0004] Although the above method can realize the through hole of thick devices, the front and back sides are etched twice, and the alignment accuracy of the etching positions of the front and back sides needs to be guaranteed; the process parameter settings need to be strictly controlled to ensure the influence of anisotropy on the hole shape during plasma etching; and two etching processes are required, resulting in the cumbersome process of processing the glass substrate in the above scheme, low processing efficiency, and difficulty in controlling the hole shape. In view of this, we propose a method for making X-shaped through holes in glass substrates. Summary of the invention

[0005] 1. Technical issues to be solved

[0006] The object of the present invention is to provide a method for manufacturing an X-shaped through hole in a glass substrate to solve the problems raised in the above background technology.

[0007] 2. Technical solution

[0008] The present invention is achieved through the following technical solutions:

[0009] A method for manufacturing an X-shaped through hole in a glass substrate, comprising:

[0010] S1. Making aluminum masks on the graphic areas on both sides of the glass substrate and exposing the positions where holes need to be opened on the glass substrate;

[0011] S2, setting the RF electrode power, etching time, vacuum pressure, total flow rate of the mixed gas of the plasma etching equipment, and setting the mixing ratio of C4F8, N2 and O2 in the mixed gas;

[0012] S3, heating the glass substrate by using a plasma etching device;

[0013] S4. Using plasma etching equipment to etch both the front and back sides of the glass substrate simultaneously.

[0014] As an optional solution of the technical solution of this application document, S1 includes the following sub-steps:

[0015] S101, sputtering an aluminum mask on both sides of the glass substrate;

[0016] S102, attaching an anti-corrosion film on the surface of the aluminum mask;

[0017] S103, exposing the pattern areas on both sides of the glass substrate to harden the resist film in the pattern areas;

[0018] S104, using a developing solution to remove the unexposed resist film to expose the aluminum mask at the position where the hole needs to be opened;

[0019] S105, plasma etching the aluminum masks exposed on both sides of the glass substrate using chlorine gas to remove the aluminum masks at positions where holes need to be opened;

[0020] S106, using an organic stripping solution to remove the hardened resist film on both sides of the glass substrate.

[0021] As an optional solution of the technical solution of this application document, in S4, the etching time is positively correlated with the thickness of the glass substrate.

[0022] As an optional solution of the technical solution of the present application document, in S4, the RF electrode power is gradually reduced.

[0023] As an optional solution of the technical solution of the present application document, in S4, the content of O2 in the mixed gas gradually increases, and the proportion of O2 in the mixed gas is 70%-80%.

[0024] As an optional solution of the technical solution of the present application document, in S4, the content of C4F8 in the mixed gas gradually decreases, and the proportion of C4F8 in the mixed gas is 10%-20%.

[0025] As an optional solution of the technical solution of this application document, in S3 and S4, the vacuum pressure is 220mtorr and the total flow rate of the mixed gas is 2500sccm.

[0026] As an optional solution of the technical solution of this application document, it also includes: S5, using plasma etching equipment to actively recover and treat the generated waste gas.

[0027] 3. Beneficial effects

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention utilizes plasma etching equipment to simultaneously etch both the front and back sides of the glass substrate, which is beneficial to stabilizing the hole shape, simplifying the process flow, improving etching efficiency, and reducing costs.

[0030] 2. The present invention can meet the hole opening requirements of glass substrates of different thicknesses by setting different etching times.

[0031] 3. The present invention can control the shape of the through hole by gradually reducing the proportion of the mixed gas during the etching process, forming an X-shaped through hole on the glass substrate, facilitating copper plating in the through hole, reducing the insufficient plating thickness and the incidence of voids in the hole, and realizing electrical connection between different circuit layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a logic block diagram of a method for making an X-shaped through hole in a glass substrate;

[0033] Figure 2 It is an etching effect diagram of a method for making an X-shaped through hole in a glass substrate;

[0034] Figure 3 This is the etching effect of the mixed gas after increasing the proportion of C4F8 and reducing the proportion of O2;

[0035] Reference numerals: 1. glass substrate; 2. aluminum mask. DETAILED DESCRIPTION

[0036] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0037] See also Figure 1 The present invention provides a method for manufacturing an X-shaped through hole in a glass substrate, comprising:

[0038] S1, making an aluminum mask 2 on the graphic areas on both sides of the glass substrate 1, and exposing the positions where holes need to be opened on the glass substrate 1;

[0039] S2, setting the RF electrode power, etching time, vacuum pressure, total flow rate of the mixed gas of the plasma etching equipment, and setting the mixing ratio of C4F8, N2 and O2 in the mixed gas;

[0040] S3, heating the glass substrate 1 by using a plasma etching device;

[0041] S4, etching the front and back sides of the glass substrate 1 simultaneously using a plasma etching device;

[0042] S5. Actively recover and treat the waste gas generated by plasma etching equipment.

[0043] The S1 comprises the following sub-steps:

[0044] S101, sputtering an aluminum mask 2 on both sides of a glass substrate 1;

[0045] S102, attaching an anti-corrosion film to the surface of the aluminum mask 2 (film attaching accuracy ±5mm);

[0046] S103, exposing the graphic areas on both sides of the glass substrate 1 to harden the resist film in the graphic areas (the positioning accuracy of single-side exposure is ≤5 microns, and the positioning accuracy of double-side exposure is ≤10 microns, to ensure that X-shaped through holes can be formed during simultaneous dry etching on both sides to reduce the incidence of abnormal shapes);

[0047] S104, using a developing solution to remove the unexposed resist film to expose the aluminum mask 2 at the position where a hole needs to be opened;

[0048] S105, using chlorine gas (purity: 99.999%) to perform plasma etching on the aluminum mask 2 exposed on both sides of the glass substrate 1 to remove the aluminum mask 2 at the position where the hole needs to be opened;

[0049] S106 , using an organic stripping solution to remove the hardened resist films on both sides of the glass substrate 1 .

[0050] In S2, the reaction chamber material of the plasma equipment is SUS316, the gases used are C4F8, N2 and O2 (purity: 99.999%), the vacuum pressure is 220mtorr, and the total flow rate of the mixed gas is 2500sccm.

[0051] In S4, the etching time is positively correlated with the thickness of the glass substrate 1; as the thickness of the glass substrate 1 increases, the etching time also needs to be extended; in order to achieve the opening of an X-shaped through hole on the glass substrate 1, the RF electrode power and the ratio of the mixed gas need to be adjusted during the etching process of the glass substrate 1.

[0052] The RF electrode power determines the number of excited plasma states. The greater the electrode power, the more plasma states are excited. The preferred value is (5-9KW); the gas mixing ratio determines the etching rate. By adding N2 and O2 to the mixed gas, the activity of the ions can be improved, and the F ions can be forced to separate from the C4F8, thereby increasing the etching efficiency (preferably 70%-80% O2; 10%-20% C4F8; 10% N2, and the above ratios are all volume ratios); the vacuum degree is between 180-260mtorr, preferably 220mtorr to ensure the vacuum degree of the equipment chamber at an intake flow rate of 2500sccm.

[0053] During the plasma etching process, it is necessary to gradually reduce the RF electrode power and reduce the C4F8 content in the mixed gas to control the shape of the through hole, and finally form an X-shaped through hole on the glass substrate 1, such as Figure 2 shown.

[0054] If the parameters such as the RF electrode power and the content of C4F8 in the mixed gas are not controlled, the shape of the etched through hole in the glass substrate 1 cannot be effectively controlled; when the content of C4F8 in the mixed gas remains unchanged or increases, the shape of the etched through hole will expand to both sides, and even cause a hole to be broken, making the substrate unusable. Figure 3 shown.

[0055] Compared with the prior art, this processing method can etch on both sides of the glass substrate 1 at the same time, increase etching efficiency, reduce costs, and control the shape of the hole, which is convenient for copper plating in the X-shaped through hole, reduces the insufficient plating thickness and the incidence of voids in the hole, and realizes electrical connection between different circuit layers.

[0056] The principle of etching the glass substrate 1 by the mixed gas of C4F8, N2 and O2 is:

[0057] SiO2+4F--->SiF4+2O;

[0058] SiO2+2CF2--->SiF4+2CO;

[0059] SiF4 is a volatile compound. When the waste gas generated is actively recovered and treated by plasma etching equipment in S5, adsorbents can be used to adsorb silicon tetrafluoride gas. Commonly used adsorbents include activated carbon, silica gel, molecular sieves, etc. Adsorbents can effectively remove harmful substances in silicon tetrafluoride gas, so that it meets emission standards and reduces pollution to the environment.

[0060] The following will demonstrate the etching process of glass substrates with specific cases:

[0061] Table 1: Etching process of 80mm thick glass substrate into X-shaped through holes

[0062]

[0063] Table 2: Etching process of X-shaped through-holes in 100mm thick glass substrate

[0064]

[0065] Table 3: Etching process of X-shaped through-holes in 150mm thick glass substrate

[0066]

[0067] Table 4: Etching process of X-shaped through holes in 200mm thick glass substrate

[0068]

[0069] In the above etching process, the substrate is heated for a fixed time of 15 minutes to ensure that the glass substrate can be heated from room temperature to above 80°C to enter the etching stage; in the cavity cleaning stage, the remaining gas in the cavity of the plasma etching equipment is extracted by a vacuum pump and enters the gas recovery device, and 100% O2 is supplemented at the same time to clean the cavity and substrate and prevent the direct emission of exhaust gas after the equipment opens the door, which is harmful to the human body and damages the environment.

Claims

1. A method for manufacturing an X-shaped through hole in a glass substrate, characterized in that: include: S1, making an aluminum mask (2) on the patterned areas on the front and back sides of the glass substrate (1), and exposing the position where a hole needs to be opened on the glass substrate (1); S2, setting the RF electrode power, etching time, vacuum pressure, total flow rate of the mixed gas of the plasma etching equipment, and setting the mixing ratio of C4F8, N2 and O2 in the mixed gas; S3, using a plasma etching device to heat the glass substrate (1); S4, etching the front and back sides of the glass substrate (1) simultaneously using a plasma etching device; In S4, the content of O2 in the mixed gas gradually increases, and the proportion of O2 in the mixed gas is 70%-80%; In S4, the content of C4F8 in the mixed gas gradually decreases, and the proportion of C4F8 in the mixed gas is 10%-20%.

2. The method for manufacturing an X-shaped through hole in a glass substrate according to claim 1, characterized in that: The S1 comprises the following sub-steps: S101, sputtering an aluminum mask (2) on both the front and back surfaces of a glass substrate (1); S102, attaching an anti-corrosion film to the surface of the aluminum mask (2); S103, exposing the pattern areas on both the front and back sides of the glass substrate (1) to harden the resist film in the pattern areas; S104, using a developing solution to remove the unexposed resist film, exposing the aluminum mask (2) at the location where a hole needs to be opened; S105, using chlorine gas to perform plasma etching on the aluminum mask (2) exposed on both sides of the glass substrate (1), thereby removing the aluminum mask (2) at the position where a hole needs to be opened; S106, using an organic film stripping solution to remove the hardened anti-corrosion film on both sides of the glass substrate (1).

3. The method for manufacturing an X-shaped through hole in a glass substrate according to claim 1, characterized in that: In S4, the etching time is positively correlated with the thickness of the glass substrate (1).

4. The method for manufacturing an X-shaped through hole in a glass substrate according to claim 1, characterized in that: In S4, the RF electrode power is gradually reduced.

5. The method for manufacturing an X-shaped through hole in a glass substrate according to claim 1, characterized in that: In S3 and S4, the vacuum pressure is 220 mtorr, and the total flow rate of the mixed gas is 2500 sccm.

6. The method for manufacturing an X-shaped through hole in a glass substrate according to claim 1, characterized in that: Also includes: S5. Actively recover and treat the waste gas generated by plasma etching equipment.

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