A method of evaporating and atomizing indium phosphide wafers for etching

Abstract

The application provides a method for evaporating and atomizing corrosion of an indium phosphide wafer, comprising the following steps: A) placing the indium phosphide wafer to be corroded into a rotating disc, and adding a corrosion solution into a corrosion tank; the rotating disc is arranged in a closed space above the corrosion tank, and the closed space and the corrosion tank are connected through a valve channel; the corrosion solution comprises hydrogen peroxide, sulfuric acid, phosphoric acid and hydrochloric acid; B) hot nitrogen gas is introduced into the corrosion tank to evaporate and atomize the corrosion solution, and the valve channel is opened to allow the atomized corrosion solution to enter the closed space above; C) the rotating disc is started to rotate the wafer, and the indium phosphide wafer on the rotating disc is corroded; D) the corroded wafer is taken out and cleaned to obtain the corroded indium phosphide wafer. Compared with the method of liquid phase corrosion in the prior art, the present process has the advantages of higher wafer corrosion amount, simpler operation, higher automation degree and more uniform corrosion compared with the traditional corrosion process.

Description

TECHNICAL FIELD

[0001] The application relates to a method for evaporating, atomizing and etching indium phosphide wafers. BACKGROUND

[0002] After Si and gallium arsenide (GaAs), indium phosphide (InP) has become an indispensable semiconductor material for optoelectronic devices and microelectronic devices, and is formed by combining group III element indium (In) and group V element phosphorus (P). The InP has superior characteristics that Si and Ge do not have. The band gap of the InP is about 1.4 eV, and the InP has advantages such as a large band gap and high electron mobility. Therefore, the InP can be used to manufacture high-conversion-efficiency solar cells, InP-based laser diodes, high-frequency devices and the like. However, due to the process problems in the manufacturing process, the InP polished wafer is 3-5 times more expensive than the GaAs under the same area. Therefore, optimizing the wafer production process of the InP becomes a key point for improving the quality of the InP wafer. The wafer etching link is one of the key links in the production process of the InP. After etching, the stress layer and the surface damage layer generated on the surface of the InP wafer due to the machining process such as slicing and grinding can be removed.

[0003] The commonly used InP wafer etching process in the industry is as follows: 1. The Cassette (wafer carrier) is taken out from the water tank, hung on the handle, and the wafer surface is first washed with a water gun for 15-20 seconds.

[0004] 2. Then put it into the prepared Etch (etching solution) solution and start timing, and push back and forth.

[0005] 3. After 3-6 min, take out the Cassette, quickly pass through the water box and wash with a water gun for 15-20 seconds.

[0006] 4. Then use the water gun to wash the wafer surface on the etching table for 45-50 seconds, and then put it into the etching solution for continuous etching.

[0007] 5. Repeat the above operation for a total of four times to etch the wafer, and the total time is 20 minutes.

[0008] The commonly used InP wafer etching method cannot well remove the stress layer and the surface damage layer on the wafer surface, and the etching amount is insufficient, which is easy to cause the wafer to have a drug print back invasion, and the etching operation process is relatively complicated, and the InP wafer is easy to be broken and damaged in the process of shaking the wafer and washing the wafer for many times, and is relatively dependent on manual operation, and the degree of mechanization and automation is not enough. SUMMARY

[0009] The application aims to provide a method for evaporating and atomizing to corrode indium phosphide wafers.

[0010] The application provides a method for evaporating and atomizing to corrode indium phosphide wafers, comprising the following steps:

[0011] A) placing the indium phosphide wafers to be corroded into a rotating disc, and adding a corrosion solution into a corrosion tank;

[0012] The rotating disc is arranged in a closed space above the corrosion tank, and the closed space and the corrosion tank are connected through a valve channel;

[0013] The corrosion solution comprises hydrogen peroxide, sulfuric acid, phosphoric acid and hydrochloric acid, and the volume ratio of the hydrogen peroxide, sulfuric acid, phosphoric acid and hydrochloric acid is (24-26):(0.8-1.2):(0.8-1.5):(10-20);

[0014] B) passing hot nitrogen gas into the corrosion tank to evaporate and atomize the corrosion solution, and opening the valve channel to pass the atomized corrosion solution into the closed space above;

[0015] C) starting the rotating disc to rotate the wafers, and corroding the indium phosphide wafers on the rotating disc;

[0016] D) taking out the corroded wafers to clean, and obtaining the corroded indium phosphide wafers.

[0017] Preferably, the temperature of the hot nitrogen gas is 100-200℃.

[0018] Preferably, the rotating speed of the wafers in the step C) is 100-500r / min;

[0019] The corrosion time in the step C) is 20-40min.

[0020] Preferably, after the corrosion in the step C) is completed, 0-5℃ nitrogen gas is passed in to condense the atomized corrosion solution and flow back into the corrosion tank.

[0021] Preferably, the step D) is specifically:

[0022] The corroded wafers are taken out to be sequentially soaked in water, washed with water, soaked in ethanol and spun dry.

[0023] Preferably, the step D) is specifically:

[0024] The corroded wafers are taken out to be soaked in water for 5-10s, then taken out to be washed with deionized water for 30-40s, then soaked in ethanol for 15-20s, and finally spun dry.

[0025] Preferably, the volume ratio of hydrogen peroxide, sulfuric acid, phosphoric acid and hydrochloric acid in the etching solution is 25:(0.9-1.1):(1.0-1.2):(10-15).

[0026] Preferably, the indium phosphide wafer to be etched is soaked in water for 5-10 seconds and then taken out and placed in the turntable.

[0027] The present application provides a method for evaporating and atomizing etching of an indium phosphide wafer, comprising the following steps: A) placing the indium phosphide wafer to be etched in a turntable and adding an etching solution into an etching tank; the turntable is arranged in a closed space above the etching tank, and the closed space and the etching tank are connected through a valve channel; the etching solution comprises hydrogen peroxide, sulfuric acid, phosphoric acid and hydrochloric acid, and the volume ratio of the hydrogen peroxide, sulfuric acid, phosphoric acid and hydrochloric acid is (24-26):(0.8-1.2):(0.8-1.5):(10-20); B) passing hot nitrogen gas into the etching tank to evaporate and atomize the etching solution, and opening the valve channel to pass the atomized etching solution into the closed space above; C) starting the turntable to rotate the wafer, and etching the indium phosphide wafer on the turntable; D) taking out the etched wafer to clean it, and obtaining the etched indium phosphide wafer. Compared with the method of liquid phase etching in the prior art, the method of the present application evaporates and atomizes the etching solution by filling hot nitrogen gas, and removes the stress layer and the surface damage layer on the surface of the indium phosphide wafer by high-speed rotation of the wafer in the atomized etching solution, so as to achieve the purpose of uniform wafer etching and reduction of drug print back invasion. Compared with the traditional etching process, the present process improves the wafer etching amount, is more convenient to operate, has a higher degree of automation, and etches more uniformly. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of the provided drawings.

[0029] Figure 1 The process flow diagram for evaporating and atomizing etching of an indium phosphide wafer in the present application;

[0030] Figure 2 The structural schematic diagram of the etching device used in the present application;

[0031] Figure 2 In the figure, 1 is a turntable control device, 2 is a turntable, 3 is a valve channel, 4 is an etching solution, 5 is a nitrogen gas filling inlet, and 6 is an etching tank. DETAILED DESCRIPTION

[0032] The present invention provides a method for evaporation atomization etching of indium phosphide wafers, comprising the following steps:

[0033] A) Place the indium phosphide wafer to be etched into a turntable and add etching solution into the etching tank;

[0034] The turntable is arranged in a closed space above the corrosion tank, and the closed space is connected to the corrosion tank through a valve channel;

[0035] The etching solution includes hydrogen peroxide, sulfuric acid, phosphoric acid and hydrochloric acid, and the volume ratio of the hydrogen peroxide, sulfuric acid, phosphoric acid and hydrochloric acid is (24-26): (0.8-1.2): (0.8-1.5): (10-20);

[0036] B) Introduce hot nitrogen into the etching tank to evaporate and atomize the etching liquid, and open the valve channel to allow the atomized etching liquid to pass into the enclosed space above;

[0037] C) starting a turntable to rotate the wafer and etching the indium phosphide wafer on the turntable;

[0038] D) taking out the etched wafer and cleaning it to obtain an etched indium phosphide wafer.

[0039] In the present invention, the evaporation atomization device is as follows Figure 2 As shown, the etching tank is located at the bottom, used to hold the etching solution. A nitrogen inlet is set on the side. Above the etching tank is a closed space with a turntable installed. The turntable is used to place the wafers to be etched. The turntable's speed is controlled by a turntable control device. The etching tank and the closed space containing the turntable are connected by a valve channel. Opening the valve connects the upper and lower spaces. Closing the valve separates the upper and lower spaces into two independent closed spaces.

[0040] The present invention first soaks an indium phosphide wafer to be corroded in a water tank for 5 to 10 seconds. The indium phosphide wafer to be corroded can be a ground indium phosphide wafer or a sliced ​​indium phosphide wafer.

[0041] Then take out the wafer from the water tank, put it into the turntable, and add etching liquid into the etching tank.

[0042] In the present invention, the turntable is preferably made of polypropylene (PP) and is resistant to high temperatures and corrosion. The corrosive liquid preferably includes hydrogen peroxide, sulfuric acid, phosphoric acid, and hydrochloric acid, and the turntable is designed with a groove for fixing the wafer. The volume ratio of the hydrogen peroxide, sulfuric acid, phosphoric acid, and hydrochloric acid is (24-26):(0.8-1.2):(0.8-1.5):(10-20), more preferably 25:(0.9-1.1):(1.0-1.2):(10-15). Specifically, in an embodiment of the present invention, it can be 25:1:1:10.

[0043] Then hot nitrogen gas is introduced into the etching tank to atomize the etching liquid, and the valve channel is opened to allow the atomized etching liquid to enter the upper sealed space.

[0044] In the present application, the temperature of the hot nitrogen gas is preferably 100-200°C, more preferably 120-180°C, such as 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, and preferably a range with any of the above values as upper or lower limit. The flow rate of the hot nitrogen gas is preferably 2-3 m / s. In the present application, the delivery pipe of the hot nitrogen gas uses a 316 stainless steel pipe with a diameter of 10 mm and an inner diameter of 8 mm.

[0045] After the atomized etching liquid fills the entire rotating disc space, the rotating disc is started, and the wafer is rotated at high speed with the rotating disc, so that the wafer is etched more uniformly after being fully contacted with the etching mist.

[0046] In the present application, the rotating speed of the rotating disc is preferably 100-500 r / min, more preferably 200-400 r / min, such as 100 r / min, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, and preferably a range with any of the above values as upper or lower limit. The etching time is preferably 20-40 min, more preferably 25-35 min, and most preferably 30 min.

[0047] After etching is completed, nitrogen gas with a lower temperature is introduced from the nitrogen gas inlet to re-condense the etching mist into etching liquid, and the etching liquid is allowed to flow back into the etching tank through the valve channel.

[0048] In the present application, the temperature of the nitrogen gas is preferably 0-5°C, more preferably 1-4°C, and most preferably 2-3°C.

[0049] The wafer after etching is placed in a water tank for immersion for 5-10 s;

[0050] Then the wafer is taken out of the water tank, rinsed with deionized water for 30-40 s, and the two sides of the wafer are rinsed clean to ensure that the wafer surface is clean and free of residual etching liquid.

[0051] Finally, the cleaned wafer is placed in alcohol for immersion for 15-20 s, and the wafer after alcohol removal is placed in a spin dryer for spin-drying.

[0052] The application provides a method for evaporating and atomizing to etch an indium phosphide wafer, comprising the following steps: A) placing the indium phosphide wafer to be etched into a rotating disc, and adding an etching solution into an etching tank; the rotating disc is arranged in a closed space above the etching tank, and the closed space is connected with the etching tank through a valve channel; the etching solution comprises hydrogen peroxide, sulfuric acid, phosphoric acid and hydrochloric acid, and the volume ratio of the hydrogen peroxide, the sulfuric acid, the phosphoric acid and the hydrochloric acid is (24-26):(0.8-1.2):(0.8-1.5):(10-20); B) introducing hot nitrogen into the etching tank to evaporate and atomize the etching solution, and opening the valve channel to introduce the atomized etching solution into the closed space above; C) starting the rotating disc to rotate the wafer, and etching the indium phosphide wafer on the rotating disc; D) taking out the etched wafer to clean, and obtaining the etched indium phosphide wafer. Compared with the method of liquid phase etching in the prior art, the etching solution is evaporated and atomized by the method of filling hot nitrogen, the wafer is rotated at high speed in the atomized etching solution, the surface stress layer and the surface damage layer of the indium phosphide wafer are removed, the wafer is uniformly thinned, and the purpose of reducing the drug print back invasion is achieved. Compared with the traditional etching process, the wafer etching thinning is improved, the operation is more simple, the automation degree is higher, and the etching is more uniform.

[0053] In order to further illustrate the application, the method for evaporating and atomizing to etch an indium phosphide wafer provided by the application is described in detail below in combination with examples, but it should not be understood as limiting the protection scope of the application.

[0054] Example 1

[0055] (1) select a group of polished 3-inch indium phosphide wafers, and immerse the wafers in a water tank for 5s;

[0056] (2) take the wafers out of the water tank and place them in a rotating disc;

[0057] (3) add the prepared etching solution, which is prepared from four chemical solutions H1 (hydrogen peroxide), H2 (sulfuric acid), H3 (phosphoric acid) and C (hydrochloric acid), and the volume ratio is H1:H2:H3:C=25:1:1:10;

[0058] (4) introduce hot nitrogen to evaporate and atomize the etching solution, and open the valve to introduce the mist into the whole rotating disc space; the temperature requirement is 100℃;

[0059] (5) when the mist fills the whole rotating disc space, the rotating disc can be started, and the wafers rotate at high speed with the rotating disc, so that the wafers are fully contacted with the etching mist and are etched more uniformly; the rotating speed requirement is 100r / min, and the etching time is 20min;

[0060] (6) After the completion of corrosion, low-temperature nitrogen is introduced to make the corrosion mist re-condense into corrosion liquid, and the valve is opened to make the corrosion liquid flow back into the corrosion tank; the temperature requirement is 0°C;

[0061] (7) The wafer after completion of corrosion is placed in a water tank for 5s;

[0062] (8) The wafer is taken out of the water tank, washed with deionized water for 30s, and both sides of the wafer are washed clean to ensure that the wafer surface is clean and free of residual chemical liquid;

[0063] (9) The cleaned wafer is placed in alcohol for 15s, and the alcohol-dehydrated wafer is placed in a spin dryer.

[0064] Example 2

[0065] (1) A group of polished 4-inch indium phosphide wafers are selected, the Cassette (wafer carrier) is taken out of the water tank and hung on the handle, and the wafer surface is first washed with a water gun for 20 seconds.

[0066] (2) Then put it into the prepared new Etch (etching solution) solution and start timing, push back and forth. The etching solution is prepared from H1 (hydrogen peroxide), H2 (sulfuric acid), H3 (phosphoric acid) and C (hydrochloric acid), and the ratio is H1:H2:H3:C=25:1:1:10 by volume.

[0067] (3) After 5 minutes, take out the Cassette, quickly pass through the water box and wash with a water gun for 20 seconds.

[0068] (4) Then use the water gun to wash the wafer surface on the etching table for 50 seconds, and then put it into the etching solution for continuous etching.

[0069] (5) Repeat the above operation four times to etch the wafer, a total of 20 minutes.

[0070] (6) The cleaned indium phosphide wafer is placed in alcohol for 20s,

[0071] (7) The indium phosphide wafer after alcohol dehydration is placed in a drying tank for 3min.

[0072] Comparative Example 1

[0073] (1) A group of polished 3-inch indium phosphide wafers are selected, the Cassette (wafer carrier) is taken out of the water tank and hung on the handle, and the wafer surface is first washed with a water gun for 15 seconds.

[0074] (2) Then put into the prepared new Etch (etchant) solution and start timing, push back and forth. Etchant is prepared by H1 (hydrogen peroxide), H2 (sulfuric acid), H3 (phosphoric acid), C (hydrochloric acid) four kinds of chemical solution, the ratio is volume ratio H1: H2: H3: C = 25:1:1:10.

[0075] (3) After 3 min, take out the cassette, quickly pass the water box and rinse with a water gun for 15 seconds.

[0076] (4) Then use the water gun to rinse the wafer surface on the etching table for 45 seconds, and then put it into the etchant for continuous etching.

[0077] (5) Repeat the above operation for a total of four times for etching the wafer, for a total of 20 minutes.

[0078] (6) Put the clean indium phosphide wafer into alcohol and soak for 15S,

[0079] (7) Put the indium phosphide wafer after water removal with alcohol into the drying tank for 2 min.

[0080] Comparative Example 2:

[0081] (1) Select a group of polished 4-inch indium phosphide wafers, take the cassette (wafer carrier) out of the water tank and hang the handle, first rinse the wafer surface with a water gun for 20 seconds.

[0082] (2) Then put into the prepared original Etch (etchant) solution and start timing, push back and forth. The original etchant is prepared by K1 (acetic acid), K2 (phosphoric acid), K3 (hydrogen peroxide) three kinds of chemical solution, the ratio is volume ratio K1: K2: K3 = 3:1:1

[0083] (3) After 5 min, take out the cassette, quickly pass the water box and rinse with a water gun for 20 seconds.

[0084] (4) Then use the water gun to rinse the wafer surface on the etching table for 50 seconds, and then put it into the etchant for continuous etching.

[0085] (5) Repeat the above operation for a total of four times for etching the wafer, for a total of 20 minutes.

[0086] (6) Put the clean indium phosphide wafer into alcohol and soak for 20S,

[0087] (7) Put the indium phosphide wafer after water removal with alcohol into the drying tank for 3 min.

[0088] The roughness of the indium phosphide wafer etched by different etching methods in the examples and comparative examples was measured by a roughness measuring instrument (zygo).

[0089] Two pieces of the finished indium phosphide wafer were randomly selected from each experimental group, and the thickness of the dried indium phosphide wafer was measured using a micrometer. Five-point measurement was adopted, i.e. the first point was the large edge / small edge, and the measurement was performed in a clockwise direction, and the last measurement point was the center point. The thickness obtained by measurement was compared with the thickness before etching, and the etching loss of the etching process was obtained by calculation. The average value of each experimental group was obtained.

[0090] Table 1 Etching effect of the same etching liquid and different etching methods of the indium phosphide wafer

[0091] Example Wafer etch away (um) Wafer roughness (nm) Example 1 11 430 Comparative Example 1 6 629

[0092] Table 2 Etching effect of the same etching method and different etching liquid ratios of the indium phosphide wafer

[0093] Example Wafer etch away (um) Example 2 9 Comparative Example 2 5

[0094] The above description is only preferred embodiments of the present application, and it should be pointed out that, for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A method for evaporating and atomizing etching of indium phosphide wafer, comprising the following steps: A) placing the indium phosphide wafer to be etched into a rotating disc and adding etching solution into an etching tank; the rotating disc is arranged in a closed space above the etching tank, and the closed space and the etching tank are connected through a valve channel; the etching solution comprises hydrogen peroxide, sulfuric acid, phosphoric acid and hydrochloric acid, and the volume ratio of the hydrogen peroxide, sulfuric acid, phosphoric acid and hydrochloric acid is 25:1:1:10; B) passing hot nitrogen gas into the etching tank to evaporate and atomize the etching solution, and opening the valve channel to pass the atomized etching solution into the closed space above; the temperature of the hot nitrogen gas is 100-200℃, C) starting the rotating disc to rotate the wafer and etching the indium phosphide wafer on the rotating disc; the rotating speed of the wafer in the step C) is 100-500r / min; the etching time in the step C) is 20-40min; D) taking out the etched wafer for cleaning to obtain the etched indium phosphide wafer.

2. The method of claim 1, wherein, after the step C) of etching is completed, 0-5℃ nitrogen gas is passed in to condense the atomized etching solution and flow back into the etching tank.

3. The method of claim 2, wherein, the step D) is specifically: taking out the etched wafer and sequentially immersing it in water, washing it with water, immersing it in ethanol and spinning it to dry.

4. The method of claim 3, wherein, the step D) is specifically: immersing the etched wafer in water for 5-10s, then taking it out and washing it with deionized water for 30-40s, immersing it in ethanol for 15-20s, and finally spinning it to dry.

5. The method according to any one of claims 1 to 4, characterized in that, immersing the indium phosphide wafer to be etched in water for 5-10s, and then taking it out and placing it into the rotating disc.

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