CN218146941U - Tubular PECVD equipment - Google Patents

Abstract

The present application discloses a tubular PECVD equipment, which comprises: a furnace tube, a graphite boat, a silicon wafer, an intake pipe, a vacuum pump and a gas supply pipe, wherein: the graphite boat is arranged in the inner cavity of the furnace tube The silicon wafer is fixed on the surface of the graphite boat; the inlet pipe is connected to the furnace door of the furnace pipe; the vacuum pump is connected to the furnace tail of the furnace pipe; the gas supply pipe is connected to the The tube wall of the furnace tube, the gas outlet of the gas supply pipe faces the graphite boat.

Description

Tubular PECVD equipment

technical field

The present application relates to the field of photovoltaic cell coating technology, in particular to a tubular PECVD equipment.

Background technique

At present, the mainstream equipment for preparing silicon nitride passivation anti-reflection films in the coating process of the photovoltaic cell industry is to use tubular plasma enhanced chemical vapor deposition (Plasma Enhanced Chemical Vapor Deposition, PECVD) equipment, using graphite boats as carriers, through In the way of high-temperature radio frequency, special gases such as silane, ammonia, and laughing gas are ionized, and the ions freely hit the silicon wafer fixed on the surface of the graphite boat under the action of an electric field, forming silicon nitride and nitrogen oxide on the surface of the silicon wafer. Silicon and silicon oxide together form a passivation anti-reflection film structure. The deposition rate and quality of passivation anti-reflection film are affected by factors such as temperature, pressure, gas flow and time in the furnace tube of tubular PECVD equipment.

In related technologies, tubular PECVD equipment is heated by thermocouples arranged on the outer wall of the furnace tube. Since the outer sheet of the graphite boat is closer to the tube wall, the heating rate is higher than that of the inner sheet of the graphite boat, resulting in the surface of the outer sheet of the graphite boat The deposition rate of passivation anti-reflection film is higher than the deposition rate of passivation anti-reflection film on the surface of graphite boat inner sheet. Therefore, the film thickness of graphite boat outer sheet is higher than the film thickness of graphite boat inner sheet, and the overall film thickness The uniformity varies greatly.

Utility model content

The present application discloses a tubular PECVD device, which solves the problem of large uniformity differences in the overall film thickness.

In order to solve the above problems, the application adopts the following technical solutions:

The embodiment of the present application discloses a tubular PECVD equipment, including: a furnace tube, a graphite boat, a silicon wafer, an air intake pipe, a vacuum pump, and a gas supply pipe, wherein: the graphite boat is arranged in the inner cavity of the furnace tube; The sheet is fixed on the surface of the graphite boat; the inlet pipe is connected to the furnace door of the furnace tube; the vacuum pump is connected to the furnace tail of the furnace tube; the gas supply pipe is connected to the furnace tube tube wall, the gas outlet of the gas supply tube faces the graphite boat.

The embodiment of the present application provides a tube type PECVD equipment, the tube type PECVD equipment includes a furnace tube, graphite boat, silicon wafer, intake pipe, vacuum pump and gas supply pipe, the graphite boat is arranged in the inner cavity of the furnace tube, and the silicon wafer is fixed on the graphite On the surface of the boat sheet of the boat, the inlet pipe is connected to the furnace door of the furnace tube, the vacuum pump is connected to the furnace tail of the furnace tube, the gas supply pipe is connected to the tube wall of the furnace tube, and the gas outlet of the gas supply pipe faces the graphite boat. In this application, the gas supply pipe connected to the wall of the furnace tube is provided, and the gas outlet faces the graphite boat arranged in the inner cavity of the furnace tube, and then the special gas is supplied to the area where the graphite boat is located in the furnace tube through the gas supply pipe, so as to improve the area where the graphite boat is located. The specific gas concentration increases the film thickness in the middle of the graphite boat, which can improve the uniformity of the overall film thickness.

Description of drawings

FIG. 1 is a schematic structural diagram of a tubular PECVD device disclosed in an embodiment of the present application.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this application.

The terms "first", "second" and the like in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific sequence or sequence. It should be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application can be practiced in sequences other than those illustrated or described herein, and that references to "first," "second," etc. distinguish Objects are generally of one type, and the number of objects is not limited. For example, there may be one or more first objects. In addition, "and/or" in the specification and claims means at least one of the connected objects, and the character "/" generally means that the related objects are an "or" relationship.

FIG. 1 is a schematic structural diagram of a tubular PECVD device disclosed in an embodiment of the present application.

As shown in Figure 1, the tubular PECVD equipment disclosed in the embodiment of the present application includes: a furnace tube 110, a graphite boat 120, a silicon wafer, an inlet pipe 130, a vacuum pump and a gas supply pipe 140, wherein: the graphite boat 120 is arranged on the The inner cavity of the furnace tube 110; the silicon chip is fixed on the surface of the graphite boat 120; the inlet pipe 130 is connected to the furnace door 111 of the furnace tube 110; The furnace end connection; the gas supply pipe 140 communicates with the tube wall of the furnace tube 110 , and the gas outlet of the gas supply pipe 140 faces the graphite boat 120 .

Based on the tubular PECVD equipment disclosed in the present application, the special gas enters the furnace tube 110 from the furnace door furnace mouth of the furnace tube 110 through the inlet pipe 130, and reacts with the silicon wafer fixed on the surface of the graphite boat 120. A passivation anti-reflection film structure composed of silicon nitride, silicon oxynitride and silicon oxide is formed on the surface, and is discharged from the furnace tail of the furnace tube 110 after the reaction is completed.

It should be noted that the furnace door is installed at the furnace mouth.

Since the vacuum pump is connected to the furnace tail of the furnace tube 110, a small amount of gas will continue to react at the furnace tail of the furnace tube 110, resulting in a generally high film thickness of the graphite boat near the furnace tail. Moreover, since the special gas enters the furnace tube 110 through the furnace door furnace mouth of the furnace tube 110, the film thickness of the graphite boat sheet is generally high near the furnace door furnace mouth, and then the graphite boat sheet is near the furnace tail. The film thickness of the position and the film thickness of the graphite boat near the furnace door are relatively uniform, that is, the film thickness of the graphite boat near the furnace tail is the same as the film thickness of the graphite boat near the furnace door. The difference is relatively small.

In this application, the gas supply pipe 140 is connected to the tube wall of the furnace tube 110, and the gas outlet of the gas supply pipe 140 is set to face the graphite boat 120. The gas supply pipe 140 is used to supplement special gas to the area where the graphite boat 120 is located in the furnace tube 110, i.e. special gas In addition to being able to enter the furnace tube 110 from the furnace door of the furnace tube 110 through the inlet pipe 130, it is also possible to enter the area where the graphite boat 120 is located in the furnace tube 110 through the gas supply pipe 140, and use the gas flow rate to move from the special gas entering position to the furnace tube 110. Diffusion around can increase the specific gas concentration in the area where the graphite boat 120 is located, improve the low deposition rate of the passivation anti-reflective film in the middle of the graphite boat 120 caused by uneven heating of the graphite boat 120, and increase the film in the middle of the graphite boat. Thick, can reduce the difference in the uniformity of the overall film thickness, improve the uniformity of the overall film thickness.

The embodiment of the present application provides a tubular PECVD equipment, which includes a furnace tube 110, a graphite boat 120, a silicon wafer, an air inlet pipe 130, a vacuum pump and a gas supply pipe 140, and the graphite boat 120 is arranged in the inner cavity of the furnace tube 110 , the silicon chip is fixed on the surface of the graphite boat 120, the furnace mouth furnace door 111 of the gas inlet pipe 130 is communicated with the furnace pipe 110, the vacuum pump is connected with the furnace tail of the furnace pipe 110, the gas supply pipe 140 is connected with the pipe wall of the furnace pipe 110, and The gas outlet of the gas pipe 140 faces the graphite boat 120 . In this application, the gas supply pipe 140 connected to the wall of the furnace tube 110 with the gas outlet facing the graphite boat 120 arranged in the inner cavity of the furnace tube 110 is set, and then through the gas supply pipe 140, special gas is supplied to the area where the graphite boat 120 is located in the furnace tube 110. Gas, increase the specific gas concentration in the area where the graphite boat 120 is located, increase the film thickness in the middle of the graphite boat, and improve the uniformity of the overall film thickness.

In the embodiment of the present application, the gas outlet of the gas supply pipe 140 faces the center of the graphite boat 120 . That is to say, the special gas is supplemented to the central position of the graphite boat 120 through the gas supply pipe 140, the special gas concentration at the central position of the graphite boat 120 is increased, and the passivation of the central position of the graphite boat 120 due to uneven heating of the graphite boat 120 is better improved. For the problem of low deposition rate of the anti-reflection film, increase the film thickness in the middle of the graphite boat, reduce the difference in the uniformity of the overall film thickness, and improve the uniformity of the overall film thickness.

When the graphite boat 120 is located at the center of the inner chamber of the furnace tube 110 , the gas outlet of the gas supply pipe 140 can be opened in the middle section of the furnace tube 110 .

The special gas in this application may include silane, ammonia, laughing gas, nitrogen, and the like.

In an implementation manner, the tubular PECVD equipment may also include a first valve and a second valve, the first valve is arranged at the gas outlet of the inlet pipe 130, and the second valve is arranged at the gas supply pipe 140 air outlet. That is to say, the first valve can be used to control whether the special gas can enter the furnace tube 110 through the inlet pipe 130 , and the second valve can be used to control whether the special gas can enter the furnace tube 110 through the gas supply pipe 140 . Due to the coating process of the photovoltaic cell industry, the process steps of preparing silicon nitride passivation anti-reflection film include: opening the furnace door to enter the boat, closing the furnace door to raise the temperature, vacuuming, leak detection, vacuuming, constant temperature and pressure, pre-deposition, deposition, cooling , breaking the vacuum, and leaving the boat, and the deposition of silicon nitride film can be divided into three steps of deposition, and its refractive index decreases successively from the bottom layer to the top layer. 1:6 and 1:10. Optionally, when depositing the top layer film, the second valve can be opened, and the special gas flow can be supplemented through the air supply pipe 140. Exemplarily, when the top layer film is deposited, the flow rate of silane gas can be 1400 sccm and the flow rate of ammonia gas can be 13580 sccm through the gas inlet pipe 130 200 sccm of silane gas and 2000 sccm of ammonia gas are fed through the gas supply pipe 140 to increase the film thickness in the middle region of the graphite boat 120 by about 3-4 nm.

In this application, as shown in FIG. 1 , the air intake pipe 130 and the air supply pipe 140 may share an air inlet. That is to say, the inlet pipe 130 and the gas supply pipe 140 can be a pipe with multiple gas outlets, and the special gas can enter the pipe through the inlet of the pipe, and then enter the furnace tube 110 from different positions through different gas outlets. Through this structure, the special gas is fed into and/or supplemented into the furnace tube 110, so that the pipeline structure of the tubular PECVD equipment can be simplified.

In an implementation manner, the tubular PECVD equipment may also include a quartz tube and a resistance wire, the resistance wire is arranged around the outer wall of the furnace tube 110, and the quartz tube is sleeved in the inner cavity of the furnace tube 110 , the graphite boat 120 is disposed in the inner cavity of the quartz tube. Exemplarily, the deposition rate of the passivation anti-reflection film can be increased by heating the resistance wire surrounding the outer wall of the furnace tube 110 and then radiating the temperature into the furnace tube 110 through the quartz tube sleeved in the inner cavity of the furnace tube 110 .

In the present application, the main body of the graphite boat is composed of a plurality of graphite boats. Exemplarily, the main body of the graphite boat includes two outer boats before and after, and the middle of the main body of the graphite boat is composed of 22 to 29 graphite boats. The boats are divided into 7 to 10 sections, and each section of the graphite boat adopts a hollow design, and the front and back sides use card points to fix the silicon wafer on the surface of the boat, and the boats are connected and fixed by ceramic rods. The distance between each boat The same, together form a similar cuboid structure. The graphite boat 120 is connected to the furnace tail electrode of the furnace tube 110 through the electrode hole at the tail of the graphite boat 120 and placed in the furnace tube 110 for reaction.

The silicon nitride passivation anti-reflection film prepared by the tubular PECVD equipment disclosed in the above embodiments can improve the uniformity of the film thickness and refractive index in the coating process, and the scheme disclosed in the embodiments of the present application is simple for equipment operation and has high feasibility , without increasing the equipment cost budget too high, suitable for mass production.

The tubular PECVD equipment provided in the embodiment of the present application can pass special gas into the center of the graphite boat through the gas supply pipe to increase the concentration of the special gas at the center of the graphite boat, which effectively compensates for the uneven heating of the graphite boat inside the furnace tube. Defects with slower deposition rates caused by central temperature skew, the experimental results are as follows:

TK_AVG RI_AVG TK_uniformity TK_CPK before improvement 74.2 2.072 6.7% 1.16 Improved 75.6 2.059 3.9% 1.37

It should be noted that no air supply pipe is before improvement, and adding air supply pipe is after improvement. TK (Thickness) is used to indicate film thickness, RI (Refractive index) is used to indicate refractive index, and CPK (Complex Process Capability index) is used to indicate process capability index of.

According to the above experimental data, it can be seen that: 1. The average value of the overall film thickness before and after improvement is within the control range; 2. The uniformity of film thickness after improvement is 3.9%, which is better than 6.7% before improvement; 3. The film thickness after improvement is CPK1.37( Between 1.33 and 1.67) The process capability is sufficient, which is higher than 1.16 before improvement.

The above-mentioned embodiments of this application focus on the differences between the various embodiments. As long as the different optimization features of the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, here No longer.

The above descriptions are only examples of the present application, and are not intended to limit the present application. For those skilled in the art, various modifications and changes may occur in this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims (5)

1. A tubular PECVD apparatus, comprising: furnace tube, graphite boat, silicon chip, intake pipe, vacuum pump and air supplement pipe, wherein:

the graphite boat is arranged in the inner cavity of the furnace tube;

the silicon chip is fixed on the surface of the boat piece of the graphite boat;

the air inlet pipe is communicated with a furnace opening and a furnace door of the furnace tube;

the vacuum pump is connected with the furnace tail of the furnace tube;

the air supply pipe is communicated with the pipe wall of the furnace pipe, and an air outlet of the air supply pipe faces the graphite boat.

2. The tubular PECVD apparatus of claim 1, wherein the gas supply tube has a gas outlet facing the center of the graphite boat.

3. The tubular PECVD apparatus of claim 1, further comprising a first valve and a second valve, wherein the first valve is disposed at the outlet of the gas inlet tube, and the second valve is disposed at the outlet of the gas supply tube.

4. The tubular PECVD apparatus of claim 1, wherein the gas inlet tube and the gas supply tube share a gas inlet.

5. The tubular PECVD apparatus of claim 1, further comprising a quartz tube and a resistance wire, wherein the resistance wire is arranged around the outer wall of the furnace tube, the quartz tube is sleeved in the inner cavity of the furnace tube, and the graphite boat is arranged in the inner cavity of the quartz tube.

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