WO2018014568A1

WO2018014568A1 - New process for copper polishing processing of sapphire wafer

Info

Publication number: WO2018014568A1
Application number: PCT/CN2017/076570
Authority: WO
Inventors: 赵能伟
Original assignee: 常州亿晶光电科技有限公司
Priority date: 2016-07-19
Filing date: 2017-03-14
Publication date: 2018-01-25
Also published as: CN106217190A

Abstract

Provided is a new process for the copper polishing processing of a sapphire wafer, belonging to the field of LED substrate processing. Scratches caused in the previous procedure are removed gradually by selecting three different polishing solutions with hardnesses from high to low, fixing the injection order of the polishing solutions and controlling the injection times of the polishing solutions, so that a relatively small damaged layer is formed on the surface of a final product, thus achieving the purpose of reducing the scratches the surface of the sapphire. The process is simple to operate and has an obvious effect.

Description

A new process for copper sapphire wafer copper polishing

Technical field

The invention relates to a new technology of copper throwing processing of sapphire wafers, belonging to the field of LED substrate processing.

Background technique

Sapphire is the main substrate material for making blue LEDs today. It is made of high purity alumina through crystal pulling, slicing, grinding, chamfering, annealing, copper polishing, polishing and cleaning. The copper throw is to remove the defects caused by the previous process to the wafer, and the removal amount is generally 20 μm.

At present, many technical solutions have been proposed to improve the polishing of sapphire. Sapphire polishing methods generally have mechanical, chemical and mechanochemical polishing methods. Mechanical polishing is to polish the wafer with hard abrasive, but the Mohs hardness of sapphire is 9 second only to diamond, so it is difficult to polish the surface by mechanical grinding, and the mechanical polishing method makes the surface quality of the substrate not High, and deep subsurface damage, resulting in reduced product performance and processing yield; chemical polishing with low polishing speed and reduced surface topography accuracy; chemical mechanical polishing combines the advantages of mechanical and chemical polishing, There are obvious improvements in polishing rate, polishing precision, and surface damage. The above-mentioned sapphire polishing methods have their own characteristics, but there are problems such as corrosion pits and micro-cracks on the surface after polishing.

As LED products have higher requirements for luminescence performance, their requirements for the entire substrate material, sapphire, are getting higher and higher. Each process will affect the subsequent process, especially if the copper is not good, it will affect the polishing effect.

Summary of the invention

In order to solve the technical problem that the surface scratches in the sapphire polishing process are obvious in the prior art, the present invention proposes a process for improving the scratching of the sapphire surface, and discloses a new process for copper sapphire wafer copper polishing. The subsequent polishing process lays the foundation.

The technical solution adopted by the invention is:

In the prior art, the sapphire wafer is usually polished by using a diamond polishing solution. Due to the high hardness of the diamond polishing solution, defects such as scratches on the sapphire wafer are easily formed, so that the subsequent processes cannot be removed; the present invention selects three different hardnesses from high to low. The polishing liquid, the spraying sequence of the fixed polishing liquid, and the spraying time of the polishing liquid are controlled to gradually remove the scratches caused by the previous process, thereby forming a small damage layer on the surface of the final product, so as to reduce the scratching of the surface of the sapphire. .

The polishing liquid for sapphire wafer copper polishing as described above includes a diamond polishing liquid, a boron carbide (BC) polishing liquid, and a silicon dioxide (SiO ₂ ) polishing liquid.

The specific process for copper sapphire wafer copper polishing is:

Firstly, the diamond polishing liquid is sprayed on the polishing liquid machine which sprays the diamond polishing liquid, and is polished for a few minutes to reach a certain amount of removal. Then, the machine is sprayed with a boron carbide polishing liquid to spray the boron carbide polishing liquid, and finally the sprayed dioxide is used. The machine for the silicon polishing liquid sprays the silica polishing liquid, and the ejection time of each polishing liquid in the above-described spraying process is different.

As described above, the injection time of the diamond polishing liquid is: spraying 2s off for 3s; the injection time of the boron carbide polishing liquid is: spraying 2s off 2s; the spraying time of the silica polishing liquid is: spraying 3s off 1s.

The flow rate of the diamond polishing solution, the boron carbide polishing liquid, and the silica polishing liquid is controlled by a constant pressure arc surface injection method, and the flow rate and distribution of the polishing liquid are controlled by controlling the injection time and the spray shape.

The sapphire wafer is subjected to copper throwing by the method of the invention, and the hardness of the three polishing liquids is different, so that the removal amount can be improved and the surface scratches can be improved. At the same time, the arc surface jetting technique is adopted for the polishing liquid. The jet is on the surface of the copper plate.

Advantageous Effects of the Invention: The present invention fixes the spraying order of three kinds of polishing liquids by selecting a polishing liquid having different hardnesses of diamond/carboconium carbide/silica in order from the highest to the bottom, and controls the spraying time of the polishing liquid, The sapphire wafer is subjected to copper polishing, and the previous process is gradually removed to the sapphire wafer. The resulting scratches, which in turn cause a small damage layer on the surface of the final product; this method can significantly improve the surface scratches of the sapphire wafer and achieve the required removal, in addition, shorten the production process and reduce production. The cost and the effect achieved are obvious.

detailed description

The following is further described in detail with reference to the embodiments:

Example 1:

The copper polishing process of the present invention is carried out according to the following steps:

After the wafer is annealed and cleaned, it is sent to a copper polishing workshop, and a copper blasting machine is provided with a machine for spraying different polishing liquids to perform copper polishing (a. diamond polishing liquid, b. boron carbide polishing liquid, c. silica polishing liquid).

Specific steps are as follows:

a, visual inspection;

b, distinguish the thickness;

c, waxing;

d. Copper throwing on the machine equipped with diamond polishing liquid;

e. Copper throwing on the machine equipped with boron carbide polishing solution;

f. Copper throwing on a machine equipped with a silica polishing solution.

Wherein, in step a, the surface having the defect is inspected as a copper throwing surface, and the marking is performed.

In step b, wafers of different thicknesses are distinguished for waxing.

In step c, waxing is performed according to a normal process, and the thickness thereof is measured, and data is recorded.

In step d, copper throwing is performed on a machine equipped with a diamond polishing liquid, and the spraying time of the diamond polishing liquid is: spraying for 2 s for 3 s.

In step e, copper throwing is performed on a machine equipped with a boron carbide polishing liquid, and the injection time of the boron carbide polishing liquid is: spraying for 2 s for 2 s.

Step f, copper throwing is performed on a machine equipped with a silica polishing liquid, and the injection time of the boron carbide polishing liquid is: spraying for 3 s for 1 s.

Table 1 Comparison of the roughness and scratch of the conventional method and the method of the present invention after polishing

Claims

A new process for copper throwing processing of sapphire wafers, characterized in that: the process is: selecting three different polishing liquids with high to low hardness, fixing the spraying sequence of three kinds of polishing liquids, controlling different polishing during spraying The jetting time of the liquid is performed on the sapphire wafer by copper throwing.
A new process for copper sapphire wafer copper polishing according to claim 1, wherein the three polishing fluids having a high to low hardness are: diamond polishing liquid, boron carbide polishing liquid, and silica polishing. liquid.
A new process for copper sapphire wafer copper polishing according to claim 1, wherein the polishing liquid is sprayed in the order of: first spraying a diamond polishing liquid, then spraying a boron carbide polishing liquid, and finally spraying the silicon dioxide polishing. liquid.
A novel process for copper throwing of sapphire wafers according to claim 1, wherein the spraying of each of the polishing liquids is carried out on a respective polishing liquid machine.
A new process for copper sapphire wafer copper polishing according to claim 1, wherein the jetting time of the diamond polishing liquid is: spraying 2s off for 3s; the injection time of the boron carbide polishing solution is: spraying 2s off 2s The spraying time of the silica polishing liquid is: spraying for 3 s for 1 s.
A novel process for copper sapphire wafer copper polishing according to claim 1, wherein the flow rate of the diamond polishing liquid, the boron carbide polishing liquid, and the silica polishing liquid is controlled by a constant pressure arc spray method.