阅读说明：本技术 一种在玻璃晶圆表面制备金属层的方法 (Method for preparing metal layer on surface of glass wafer ) 是由 陶余凡 于 2021-08-05 设计创作，主要内容包括：本发明提出了一种在玻璃晶圆表面制备金属层的方法,包括如下步骤：S1、采用等离子刻蚀工艺清洗玻璃晶圆；S2、将光刻胶均匀旋涂至所述玻璃晶圆表面,形成第一键合层；S3、以化剂溶解所述第一键合层的边缘部分,获得第二键合层,所述第二键合层的直径小于所述第一键合层；S4、以溅射工艺溅射金属于S2中所得玻璃晶圆表面,获得金属层,其中,所述第二键合层表面的金属层与所述边缘部分的金属层厚度相等。本发明通过以化剂溶解位于玻璃晶圆边缘的键合层,于玻璃晶圆边缘金属层直接与玻璃镜与阿尼相接触,相比于金属层与键合层之间的结合力,金属层与玻璃晶圆的表面结合力更强。(The invention provides a method for preparing a metal layer on the surface of a glass wafer, which comprises the following steps: s1, cleaning the glass wafer by adopting a plasma etching process; s2, uniformly spin-coating photoresist on the surface of the glass wafer to form a first bonding layer; s3, dissolving the edge part of the first bonding layer by using a reagent to obtain a second bonding layer, wherein the diameter of the second bonding layer is smaller than that of the first bonding layer; and S4, sputtering metal on the surface of the glass wafer obtained in the step S2 by a sputtering process to obtain a metal layer, wherein the thickness of the metal layer on the surface of the second bonding layer is equal to that of the metal layer on the edge part. According to the invention, the bonding layer positioned at the edge of the glass wafer is dissolved by the chemical agent, the metal layer at the edge of the glass wafer is directly contacted with the glass mirror and the anib, and the surface bonding force between the metal layer and the glass wafer is stronger than the bonding force between the metal layer and the bonding layer.)

1. A method for preparing a metal layer on the surface of a glass wafer is characterized by comprising the following steps:

s1, cleaning the glass wafer by adopting a plasma etching process;

s2, uniformly spin-coating photoresist on the surface of the glass wafer to form a first bonding layer;

s3, dissolving the edge part of the first bonding layer by using a reagent to obtain a second bonding layer, wherein the diameter of the second bonding layer is smaller than that of the first bonding layer;

and S4, sputtering metal on the surface of the glass wafer obtained in the step S2 by a sputtering process to obtain a metal layer, wherein the thickness of the metal layer on the surface of the second bonding layer is equal to that of the metal layer on the edge part.

2. The method for preparing the metal layer on the surface of the glass wafer as claimed in claim 1, wherein the chemical agent is propylene glycol methyl ether.

3. The method for preparing the metal layer on the surface of the glass wafer as claimed in claim 1, wherein the edge part of the first bonding layer is dissolved by a chemical agent in a range of 0.8-1 mm.

4. The method for preparing the metal layer on the surface of the glass wafer as claimed in claim 1, wherein a needle for dissolving the first bonding layer is fixed on the edge of the glass wafer, and the agent is sprayed onto the glass wafer from the needle at a flow rate of 10-12 ml/min.

5. The method as claimed in claim 2, wherein the glass wafer is rotated clockwise or counterclockwise at 500-600rpm during the dissolution of the first bonding layer with the reagent.

6. The method for preparing a metal layer on a glass wafer surface as claimed in claim 1, wherein before the glass wafer is etched by plasma, the surface of the glass wafer is cleaned by a cleaning solution, wherein the cleaning solution is introduced with CO₂Pure water of gas.

7. The method as claimed in claim 3, wherein after the edge-washing process is completed, the glass wafer is placed in a curing device and fixed with a volatilizing agent, and the curing temperature is 275 ℃ and 325 ℃.

8. The method as claimed in claim 1, wherein the step of soft-baking the glass wafer is performed before the step of plasma etching the glass wafer, after the step of dissolving the edge portion of the first bonding layer with a reagent, and after the step of curing the glass wafer, wherein the soft-baking temperature is 100-150 ℃.

9. The method for preparing the metal layer on the surface of the glass wafer as claimed in claim 1, wherein the metal sputtered on the surface of the glass wafer is selected from Al or Ti.

10. A substrate obtained by the method for preparing a metal layer on the surface of a glass wafer according to any one of claims 1 to 9, wherein the separable substrate comprises a metal layer, a bonding layer and a glass wafer in sequence from top to bottom, the bonding layer has a smaller diameter than the glass wafer, and the metal layer and the glass wafer are tightly combined at the edges.

Technical Field

The invention relates to the technical field of semiconductor packaging, in particular to a method for preparing a metal layer on the surface of a glass wafer.

Background

The chip packaging process is generally performed as follows: firstly, a substrate needs to be prepared, operations such as wiring and the like are carried out on the surface of the separable substrate, then the chip is inversely arranged on the surface of the substrate which is subjected to the operations such as wiring and the like, the substrate is turned over by 180 degrees after being molded, the bottom substrate is separated by utilizing laser dissolution bonding, then the metal bump is prepared, and the packaging is completed.

At present, the process for preparing a separable substrate is as follows: the method comprises the steps of carrying out a plasma etching process on a glass wafer, uniformly coating a RL (release layer) on the surface of the glass wafer through a gluing process, and depositing a layer of metal on the RL through a sputtering process to form a metal layer. When the metal layer is subjected to laser debonding, the PI (polyimide) layer is protected, and the PI is prevented from being damaged; and in the operation, make things convenient for board laser centering. And after laser de-bonding, polishing the metal layer to expose the PI and the wiring wrapped by the PI, thereby preparing the metal bump.

However, in this process, the bonding force between the RL and the glass wafer is weak due to the thin bonding layer, which easily causes the delamination defect at the edge of the glass wafer. How to control the generation of the defects is very important for improving the production line yield.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, provides a method for preparing a metal layer on the surface of a glass wafer, and solves the layering defect of RL and glass wafer in the traditional process.

In order to solve the technical problems, the invention adopts the technical scheme that: a method for preparing a metal layer on the surface of a glass wafer comprises the following steps:

s1, cleaning the glass wafer by adopting a plasma etching process;

s2, uniformly spin-coating photoresist on the surface of the glass wafer to form a first bonding layer;

s3, dissolving the edge part of the first bonding layer by using a reagent to obtain a second bonding layer, wherein the diameter of the second bonding layer is smaller than that of the first bonding layer;

and S4, sputtering metal on the surface of the glass wafer obtained in the step S2 by a sputtering process to obtain a metal layer, wherein the thickness of the metal layer on the surface of the second bonding layer is equal to that of the metal layer on the edge part.

Furthermore, the agent is propylene glycol methyl ether.

Further, the edge part of the first bonding layer is dissolved by a chemical agent to be in a range of 0.8-1 mm.

Further, a needle head used for dissolving the first bonding layer is fixed on the edge of the glass wafer, and the agent is sprayed to the glass wafer from the needle head at the flow rate of 10-12 ml/min.

Further, during the process of dissolving the first bonding layer with the reagent, the glass wafer rotates clockwise or counterclockwise at 500-600 rpm.

Further, before the glass wafer is etched by plasma, the surface of the glass wafer is cleaned by a cleaning solution which is introduced with CO₂Pure water of gas.

Further, after the edge washing process is completed, the glass wafer is placed in a curing device and fixed by a volatilizing agent, and the curing temperature is 275-.

Further, before the glass wafer is plasma-etched, after the edge part of the first bonding layer is dissolved by a chemical agent, and after the glass wafer is solidified, soft baking is carried out on the glass wafer, wherein the soft baking temperature is 100-150 ℃.

Further, the metal sputtered onto the surface of the glass wafer is selected from Al or Ti.

The separable substrate comprises a metal layer, a bonding layer and a glass wafer from top to bottom in sequence, the diameter of the bonding layer is smaller than that of the glass wafer, and the metal layer and the glass wafer are tightly combined at the edges.

Compared with the prior art, the invention has the beneficial effects that: by dissolving the bonding layer at the edge of the glass wafer with a reagent, the metal layer at the edge of the glass wafer is directly contacted with the glass wafer, and the surface bonding force between the metal layer and the glass wafer is stronger than the bonding force between the metal layer and the bonding layer.

Drawings

The disclosure of the present invention is illustrated with reference to the accompanying drawings. It is to be understood that the drawings are designed solely for the purposes of illustration and not as a definition of the limits of the invention. In the drawings, like reference numerals are used to refer to like parts. Wherein:

FIG. 1 is a flow chart of a process for forming a metal layer on a surface of a glass wafer.

FIG. 2 is a schematic diagram of an edge washing process.

FIG. 3 is a schematic view of the surface of a glass wafer before edge cleaning.

FIG. 4 is a schematic view of the surface of a glass wafer after edge washing.

Fig. 5 is a schematic cross-sectional view of a detachable substrate.

Reference numbers in the figures: 1-glass wafer, 2-bonding layer, 3-metal layer and 4-needle head.

Detailed Description

It is easily understood that according to the technical solution of the present invention, a person skilled in the art can propose various alternative structures and implementation ways without changing the spirit of the present invention. Therefore, the following detailed description and the accompanying drawings are merely illustrative of the technical aspects of the present invention, and should not be construed as all of the present invention or as limitations or limitations on the technical aspects of the present invention.

An embodiment according to the present invention is shown in connection with fig. 1. A method for preparing a metal layer on the surface of a glass wafer comprises the following steps:

and S1, cleaning the surface of the glass wafer.

In this step, a cleaning solution is first prepared: introducing CO into pure water₂A gas. CO 2₂Molecule and H₂The O molecules combine to form a weak electrolyte H₂CO₃Can remove the static electricity (electrons or charges) generated on the surface of the glass wafer, wherein CO is introduced₂The pressure of (A) is 0.3. + -. 0.1 MPa. After the glass wafer is cleaned by the cleaning solution, residual water vapor on the surface of the glass wafer is removed in a soft baking mode.

And S2, cleaning the glass wafer in a plasma etching mode to change the surface roughness of the glass wafer.

This step is performed in a plasma etcher. The working mode of the plasma etcher is as follows: under vacuum low pressure, radio frequency generated by an ICP radio frequency power supply is output to a toroidal coupling coil, mixed etching gas in a certain proportion generates high-density plasmas through coupled glow discharge, the plasmas bombard the surface of a substrate under the action of the RF radio frequency of a lower electrode in a plasma etching machine, chemical bonds of semiconductor materials in a substrate pattern area are broken, volatile substances are generated with the etching gas, and the volatile substances are separated from the substrate in a gas form and are pumped away from a vacuum pipeline.

And S3, coating the first bonding layer on the surface of the glass wafer in a spin coating mode.

The first bonding layer can be made of photoresist, and in order to ensure the uniformity of photoresist coating, the step is carried out in a coater. The glue spreader is provided with a rotatable rotating shaft or a rotating disc, the glass wafer can be arranged on the rotatable rotating shaft or the rotating disc to be fixed, a baffle is arranged above the glass wafer at a certain distance from the glass wafer, the photoresist is dripped to the upper surface of the glass wafer, the rotating shaft or the rotating disc is rotated, and the baffle above the glass wafer can scrape redundant photoresist to ensure the uniformity of photoresist coating.

And S4, dissolving the first bonding layer which is 0.8-1mm away from the edge of the glass wafer by using a chemical agent.

S3、The edge washing device is arranged in the glue spreader and comprises a needle head for chemical edge removal, the edge washing process schematic diagram shown in figure 2 is shown, the needle head is arranged above the glass wafer, the agent is sprayed to the surface of the glass wafer through the needle head, the glass wafer is still arranged on the turntable, the uniform speed clockwise or anticlockwise rotation of the glass wafer is ensured, and the edge washing range can be adjusted by adjusting the position of the needle head. In the embodiment shown in fig. 3 to 4, the adjustable washing edge range of the needle is 0.8-1mm in the edge portion. Propylene glycol methyl ether is selected as a chemical agent in the process of dissolving the first bonding layer, the flow rate is 10-12ml/min, and the rotating speed of the turntable is 500-600 rpm; and removing the water vapor on the bonding layer or the glass wafer in a soft baking mode after the dissolution is finished.

In the embodiment of the application, a first bonding layer is formed in the preparation process of the bonding layer, and a second bonding layer is obtained after the edge part of the first bonding layer is dissolved, wherein the second bonding layer is the bonding layer.

S5, placing the glass wafer obtained in the step S4 in a curing device, setting the curing temperature to be 275-325 ℃, removing residual solvent on the surface of the glass wafer or the bonding layer in the curing process, and promoting the volatilization of a curing agent on the glass wafer or the bonding layer; after the solidification is finished, the surface of the glass wafer is cleaned, soft baking of the glass wafer is finished at the temperature of 100-150 ℃, and residual water vapor on the surface of the glass wafer or the surface of the bonding layer is removed.

The embodiment of the application has two types, the curing device can select the curing machine and also can adopt other curing devices, and the embodiment of the application is not specifically limited.

And S6, directly sputtering metal onto the surface of the glass wafer by a sputtering process to obtain the separable substrate, wherein the metal sputtered onto the surface of the glass wafer comprises Al and Ti.

According to the technical scheme, the embodiment of the application provides a method for preparing the metal layer on the surface of the glass wafer, the surface of the glass wafer is firstly cleaned to increase the surface roughness, and when metal is sputtered onto the surface of the glass wafer, the surface of the glass wafer has defects due to the increase of the surface roughness, so that the metal is more tightly combined with the surface of the glass wafer; the propylene glycol ether and the glycol ether used in the edge washing process belong to glycol ether solvents, and the toxicity of the propylene glycol ether to human bodies is lower than that of glycol ether products, and the propylene glycol ether belongs to low-toxicity ethers. Propylene glycol methyl ether has weak ether smell but no strong pungent smell, so that the application of the propylene glycol methyl ether is wider and safer. Because the molecular structure of the polyether has ether group and hydroxyl group, the polyether has excellent solubility, proper volatilization rate and reaction activity, and greatly improves the safety of the production process.

As shown in fig. 5, an embodiment of the present application provides a substrate, which sequentially includes a metal layer, a bonding layer, and a glass wafer from top to bottom, wherein the upper surface of the glass wafer is tightly bonded to the metal layer at an edge, the diameter of the bonding layer is smaller than that of the glass wafer, an edge recess and a middle protrusion structure are formed between the glass wafer and the bonding layer, and after metal is sputtered on the surface, an edge recess and a middle protrusion structure are still formed. The advantages of this structure are: the edge of the metal layer is directly contacted with the upper surface of the glass wafer, and compared with the bonding force between the metal layer and the bonding layer, the bonding force between the metal layer and the surface of the glass wafer is stronger, so that the problem of edge delamination is solved.

The present application is further illustrated by the following specific examples.

Example 1

The substrate was prepared as follows:

s1, cleaning the surface of the glass wafer;

s2, cleaning the glass wafer in a plasma etching mode to change the surface roughness of the glass wafer;

s3, coating the bonding layer on the surface of the glass wafer in a spin coating mode;

s4, dissolving the bonding layer which is 0.8mm away from the edge of the glass wafer by using a chemical agent;

propylene glycol methyl ether is selected as a curing agent in the process of dissolving the bonding layer, the flow rate is 10ml/min, and the rotating speed of a turntable is 500 rpm; and removing the water vapor on the bonding layer or the glass wafer in a soft baking mode after the dissolution is finished. In the embodiment of the application, the adjustable washing edge range of the needle head is 0.8mm of the edge part.

S5, placing the glass wafer obtained in the step S4 in a curing device, and setting the curing temperature to 275 ℃; and after the solidification is finished, cleaning the surface of the glass wafer and finishing soft baking of the glass wafer at 100 ℃.

And S6, directly sputtering metal onto the surface of the glass wafer by a sputtering process to obtain the separable substrate, wherein the metal sputtered onto the surface of the glass wafer comprises Al and Ti.

Example 2

The substrate was prepared as follows:

s1, cleaning the surface of the glass wafer;

s2, cleaning the glass wafer in a plasma etching mode to change the surface roughness of the glass wafer;

s3, coating the bonding layer on the surface of the glass wafer in a spin coating mode;

s4, dissolving the bonding layer which is 1mm at the edge of the glass wafer by using a reagent;

propylene glycol methyl ether is selected as a curing agent in the process of dissolving the bonding layer, the flow rate is 12ml/min, and the rotating speed of a turntable is 600 rpm; and removing the water vapor on the bonding layer or the glass wafer in a soft baking mode after the dissolution is finished. In the embodiment of the application, the adjustable edge washing range of the needle head is 1mm at the edge part;

s5, placing the glass wafer obtained in the S4 in a curing device, and setting the curing temperature to be 325 ℃; after the solidification is finished, the surface of the glass wafer is cleaned, and the soft baking of the glass wafer is finished at 150 ℃.

And S6, directly sputtering metal onto the surface of the glass wafer by a sputtering process to obtain the separable substrate, wherein the metal sputtered onto the surface of the glass wafer comprises Al and Ti.

Comparative example 1

The only difference from embodiment 1 is that S5 is executed directly after S3 is executed, and other steps are not changed and are not described herein again.

After the substrate is prepared by the above embodiment, the surface of the substrate is observed whether there is warpage, and if so, the edge where the warpage is located is continuously observed whether delamination exists.

The results show that example 1 and example 2 do not have edge delamination, whereas comparative example 1 has edge delamination. From the above results, it can be seen that the addition of S4 can solve the problem of edge delamination.

The technical scope of the present invention is not limited to the above description, and those skilled in the art can make various changes and modifications to the above-described embodiments without departing from the technical spirit of the present invention, and such changes and modifications should fall within the protective scope of the present invention.