A method for etching back-plated DBR layer

Abstract

The present invention proposes a method for etching a back-plated DBR layer, the method comprising: placing a wafer with a back-plated DBR layer facing upward, and performing gas etching on the DBR layer to form an uneven DBR layer; performing liquid etching on the wafer after gas etching to form a wafer with the DBR layer peeled off. The method for etching a back-plated DBR layer proposed by the present invention has a simple and convenient process flow. First, the DBR layer is subjected to gas etching to form an uneven DBR layer. Then, the uneven DBR layer can be fully etched by etching liquid to achieve the effect of peeling off the DBR layer. The whole process has a low degree of manual participation, reducing the cost of machinery and labor. It also reduces the probability of fragmentation caused by manual labor.

Description

Technical Field

[0001] The present application relates to the field of electronic component processing, and in particular to a method for etching a back-plated DBR layer. Background Art

[0002] With the continuous improvement of LED (light emitting diode) luminous efficiency, LED has become one of the most valued light sources in recent years. At present, the competition in the industry is becoming increasingly fierce, and how to improve the yield and reduce costs has become the focus of each company. In the process of manufacturing LED chips, there is a back-plating DBR process to improve the brightness. However, the DBR rework involved in the current chip manufacturing process is still done by grinding because there is almost no effective solution to dissolve the TiO in the DBR.

[0003] At present, the more commonly used rework method is: use a waxing machine to apply wax on the front side of the wafer → use a soft polishing machine to soft polish the DBR layer on the back → apply wax → clean.

[0004] However, in practical application, the above method has the following defects:

[0005] 1) During the waxing and wax pressing process, the thin sheet is easily crushed due to its certain warping;

[0006] 2) After soft polishing again, the wafer will become more and more warped, resulting in an increased probability of fragmentation in subsequent processes;

[0007] 3) Whether the rework is clean requires manual visual inspection, which is prone to subjective judgment errors. It is easy to rework again if the rework is not clean;

[0008] 4) The whole process is complicated and the machinery and labor costs are high. Summary of the invention

[0009] In order to solve one of the above technical problems, the present invention provides a method for etching a back-plated DBR layer.

[0010] A first aspect of an embodiment of the present invention provides a method for etching a back-plated DBR layer, the method comprising:

[0011] The wafer back-plated DBR layer faces upward, and the DBR layer is gas-etched to form an uneven DBR layer;

[0012] The gas-etched wafer is then liquid-etched to form a wafer with the DBR layer removed.

[0013] Preferably, the gas used for gas etching the DBR layer is a fluorine-containing gas.

[0014] Preferably, the process of forming the uneven DBR layer after gas etching the DBR layer is:

[0015] Place the wafer with the DBR layer on the back facing upward in an ICP machine;

[0016] Using the fluorine-containing gas to perform gas etching on the DBR layer;

[0017] During the process of gas etching the DBR layer by the fluorine-containing gas, the parameters of the fluorine-containing gas or the ICP machine are changed to form an uneven DBR layer.

[0018] Preferably, the process of changing the fluorine-containing gas parameters to form the uneven DBR layer is:

[0019] During the process of gas etching the DBR layer by the fluorine-containing gas, the flow of argon and / or nitrogen in the fluorine-containing gas is closed or reduced to form an uneven DBR layer with a uniformity of more than 10%.

[0020] Preferably, the process of changing the parameters of the fluorine-containing gas to form the uneven DBR layer is:

[0021] During the process of gas etching the DBR layer by the fluorine-containing gas, the pressure of the fluorine-containing gas during its flow is changed to form an uneven DBR layer with a uniformity of more than 10%.

[0022] Preferably, the process of changing the parameters of the fluorine-containing gas to form the uneven DBR layer is:

[0023] During the process of gas etching the DBR layer by the fluorine-containing gas, the dissociation power or bias power of the ICP machine is changed to form an uneven DBR layer with a uniformity of more than 10%.

[0024] Preferably, the liquid used to perform liquid etching on the wafer after gas etching is a BOE solution or an HF acid solution.

[0025] Preferably, the process of subjecting the gas-etched wafer to liquid etching to form a wafer with a stripped DBR layer is:

[0026] placing the gas-etched wafer in the BOE solution or HF acid solution;

[0027] The SiO2 exposed on the DBR layer is etched by the BOE solution or the HF acid solution, and then penetrates into other components to continue etching until the DBR layer is completely peeled off from the back side of the wafer, thereby forming a wafer with the DBR layer peeled off.

[0028] Preferably, before placing the wafer with the DBR layer back-plated upward and performing gas etching on the DBR layer to form an uneven DBR layer, the method further comprises:

[0029] A photoresist is coated on the front side of the wafer.

[0030] Preferably, after liquid etching the gas-etched wafer to form a wafer with a stripped DBR layer, the method further comprises:

[0031] removing the photoresist;

[0032] The wafer with the photoresist removed is baked.

[0033] The beneficial effects of the present invention are as follows: The method for etching the back-plated DBR layer proposed by the present invention has a simple and convenient process flow. First, the DBR layer is etched by gas to form an uneven DBR layer. Then, the uneven DBR layer can be fully etched by etching liquid to achieve the effect of peeling the DBR layer. The whole process has a low degree of manual participation, reducing the cost of machinery and labor. It also reduces the probability of fragmentation caused by manual labor. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0035] Figure 1 A schematic flow chart of a method for etching a back-plated DBR layer according to an embodiment of the present invention;

[0036] Figure 2 A schematic diagram of the structure of the uneven DBR layer according to an embodiment of the present invention;

[0037] Figure 3 A schematic diagram of liquid etching of a DBR layer according to an embodiment of the present invention;

[0038] Figure 4 A schematic diagram of a wafer with a DBR layer peeled off according to an embodiment of the present invention;

[0039] Figure 5 It is a schematic diagram of a wafer coated with photoresist according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the technical solutions and advantages in the embodiments of the present application more clearly understood, the exemplary embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0041] like Figure 1 As shown, this embodiment provides a method for etching a back-plated DBR layer, and the method specifically includes:

[0042] S101, placing the DBR layer on the back of the wafer facing upward, and performing gas etching on the DBR layer to form an uneven DBR layer;

[0043] S102, performing liquid etching on the gas-etched wafer to form a wafer with the DBR layer removed.

[0044] Specifically, in this embodiment, the wafer is first placed in an ICP machine, and the DBR layer is gas-etched to form an uneven DBR layer, such as Figure 2 As shown. Then, the uneven DBR layer can be fully etched by etching liquid to achieve the effect of peeling off the DBR layer. Among them, the gas used for gas etching of the DBR layer is a fluorine-containing gas. In the process of gas etching by the fluorine-containing gas, the uneven DBR layer can be formed by changing the parameters of the fluorine-containing gas or the ICP machine. In this embodiment, the formation of an uneven DBR layer is actually equivalent to the need to obtain a DBR layer with poor uniformity. In order to obtain a DBR layer with poor uniformity, it is necessary to use a procedure that can achieve poor uniformity by changing the parameters of the fluorine-containing gas or the ICP machine. This embodiment proposes three schemes for forming an uneven DBR layer.

[0045] Solution 1

[0046] During the gas etching of the DBR layer by the fluorine-containing gas, the flow of argon and / or nitrogen in the fluorine-containing gas is closed or reduced to form an uneven DBR layer with a uniformity of more than 10%.

[0047] Specifically, the diffusion of argon and nitrogen in the gas flow plays an important role in the consistency of gas etching. Therefore, if the uniformity is poor, the flow of argon or nitrogen needs to be turned off or reduced.

[0048] Solution 2

[0049] During the process of gas etching the DBR layer by the fluorine-containing gas, the pressure of the fluorine-containing gas during the flow is changed to form an uneven DBR layer with a uniformity of more than 10%.

[0050] Specifically, in this scheme, two pressure change methods can be used to achieve the purpose of poor uniformity. One is to select a larger pressure value, which can achieve a higher etching rate at the air inlet. The other is to select a smaller pressure value, which can achieve a higher etching rate at the air extraction port. In this way, the effect of poor uniformity can be achieved.

[0051] Option 3

[0052] During the process of gas etching the DBR layer by the fluorine-containing gas, the dissociation power or bias power of the ICP machine is changed to form an uneven DBR layer with a uniformity of more than 10%.

[0053] Specifically, if the dissociation power is large, there are more free radicals, and the chemical etching is more obvious, the surface of the DBR layer will present a columnar morphology. If the bias power is large, the physical etching is more obvious, which will make the surface of the DBR layer present a concave morphology. Therefore, as long as the two are set unreasonably, the surface of the DBR layer will present an uneven morphology.

[0054] The above three solutions can be used in the gas etching process alone, or two or even three solutions can be used in the gas etching process at the same time, which is not particularly limited in this embodiment.

[0055] After gas etching, the DBR layer will present an uneven stepped planar structure. At this time, it is placed in an etching solution and soaked for a period of time. The etching solution can be a BOE solution (buffered oxide etching solution) or an HF acid solution. Since the SiO2 in the DBR layer structure is easily dissolved in the BOE / HF solution. Therefore, the solution will continuously etch the exposed SiO2 in the uneven DBR layer, such as Figure 3 As shown, it continues to penetrate into other components (SiO, TiO, etc.) and continue etching. Until the DBR layer is etched layer by layer and finally peeled off from the back of the wafer, a wafer with a peeled DBR layer is formed, as shown in FIG. Figure 4 shown.

[0056] In addition, since the present embodiment may cause certain damage to the front side of the wafer during the gas etching and liquid etching process, the present embodiment applies photoresist on the front side of the wafer before the gas etching. Figures 1 to 5 As shown. The photoresist can act as a buffer in gas etching and protect the front side of the wafer from ion bombardment. It can also act as a mask in liquid etching. After the wafer with the DBR layer stripped off is formed after liquid etching, the photoresist is removed and the wafer is baked to perform subsequent rework operations.

[0057] In summary, the overall process of the method for etching the back-plated DBR layer proposed in this embodiment can be summarized as follows: coating the front side of the wafer with photoresist → performing ICP gas etching on the back side of the wafer with the DBR layer facing up → soaking the entire wafer in solution for wet etching → removing the photoresist from the front side of the wafer and baking.

[0058] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for etching a back-plated DBR layer, characterized in that: The method comprises: The wafer back-plated DBR layer faces upward, and the DBR layer is gas-etched to form an uneven DBR layer; Liquid-etching the gas-etched wafer to form a wafer with a DBR layer removed; The gas used for gas etching of the DBR layer is a fluorine-containing gas; The process of forming an uneven DBR layer after gas etching the DBR layer is as follows: Place the wafer with the DBR layer on the back facing upward in an ICP machine; Using the fluorine-containing gas to perform gas etching on the DBR layer; During the process of gas etching the DBR layer by the fluorine-containing gas, the parameters of the fluorine-containing gas or the ICP machine are changed to form an uneven DBR layer.

2. The method according to claim 1, characterized in that The process of changing the fluorine-containing gas parameters to form an uneven DBR layer is: During the process of gas etching the DBR layer by the fluorine-containing gas, the flow of argon and / or nitrogen in the fluorine-containing gas is closed or reduced to form an uneven DBR layer with a uniformity of more than 10%.

3. The method according to claim 2, characterized in that The process of changing the parameters of the fluorine-containing gas to form an uneven DBR layer is: During the process of gas etching the DBR layer by the fluorine-containing gas, the pressure of the fluorine-containing gas during its flow is changed to form an uneven DBR layer with a uniformity of more than 10%.

4. The method according to claim 1, characterized in that The process of changing the parameters of the ICP machine to form an uneven DBR layer is as follows: During the process of gas etching the DBR layer by the fluorine-containing gas, the dissociation power or bias power of the ICP machine is changed to form an uneven DBR layer with a uniformity of more than 10%.

5. The method according to claim 1, characterized in that The liquid used to perform liquid etching on the gas-etched wafer is a BOE solution or an HF acid solution.

6. The method according to claim 5, characterized in that The process of liquid etching the gas-etched wafer to form a wafer with a stripped DBR layer is as follows: placing the gas-etched wafer in the BOE solution or HF acid solution; The SiO2 exposed on the DBR layer is etched by the BOE solution or the HF acid solution, and then penetrates into other components to continue etching until the DBR layer is completely peeled off from the back side of the wafer, thereby forming a wafer with the DBR layer peeled off.

7. The method according to claim 1, characterized in that Before placing the wafer with the DBR layer back-plated upward and performing gas etching on the DBR layer to form an uneven DBR layer, the method further includes: A photoresist is coated on the front side of the wafer.

8. The method according to claim 7, characterized in that After liquid etching the gas-etched wafer to form a wafer with a stripped DBR layer, the method further includes: removing the photoresist; The wafer with the photoresist removed is baked.

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