KR102206215B1 - Prevention of SiH4 contact to quartz tube used for deposition of wafer - Google Patents

Abstract

The present invention relates to a method of preventing contact with silane gas in a quartz tube for wafer deposition, and more particularly, in a tube system constituting a configuration of a semiconductor deposition equipment, nitrogen gas is flowed between a silicon carbide tube and a quartz tube into a silicon carbide tube. Silane gas contact of the quartz tube for wafer deposition that prevents the supplied silane gas from contacting the quartz tube, and therefore, suppresses the decrease in durability due to the phase change of the quartz tube due to the contact between the quartz tube and the silane gas. Provide a method of prevention.

Description

Prevention of SiH4 contact to quartz tube used for deposition of wafer {Prevention of SiH4 contact to quartz tube used for deposition of wafer}

The present invention relates to a method of preventing contact with silane gas in a quartz tube for wafer deposition, and more particularly, in a tube system constituting a configuration of a semiconductor deposition equipment, nitrogen gas is flowed between a silicon carbide tube and a quartz tube into a silicon carbide tube. Silane gas contact of the quartz tube for wafer deposition that prevents the supplied silane gas from contacting the quartz tube, and therefore, suppresses the decrease in durability due to the phase change of the quartz tube due to the contact between the quartz tube and the silane gas. Provide a method of prevention.

A series of processes in which a material of a desired molecular or atomic unit is deposited on a semiconductor wafer in the thickness of a thin film to give it electrical properties is called deposition. Among them, the chemical vapor deposition method (CVD) is a technique that can be used for thin film deposition of conductors, non-conductors, and semiconductors as a method of depositing particles formed by a chemical reaction of a gas in the form of water vapor given external energy. In particular, LPCVD (Low Pressure CVD) has a low pressure in the chamber and induces a reaction with high-temperature thermal energy. It is a method of forming a thin film by applying a lower pressure than APCVD, and is mainly used for forming a thin film used as a gate layer of tr. do. LPCVD has a great advantage because it can process many wafers at once. In addition, the step coverage is excellent. However, the deposition rate is slow and deterioration of the components is liable to occur due to the high temperature process.

In addition, to form a silicon film on the wafer, silane gas is flowed to deposit silicon on the wafer surface.At this time, the silane gas first injected into the silicon carbide tube flows out of the silicon carbide tube and opens and closes the silicon carbide tube and the tube. Silicon is deposited on the surface of the silicon carbide tube and the quartz tube as well as the surface of the wafer as it flows into the inner surface of the quartz tube through the gap provided between the door parts.

At this time, since the silicon carbide tube has little phase change and can be separated, deterioration due to silicon deposition can be prevented by performing separation and cleaning after the process, but in the case of a quartz tube, separation and cleaning is difficult, and a repeated deposition process Due to the phase change of quartz in the quartz tube, durability of the quartz tube is significantly deteriorated. Therefore, the quartz tube is cracked and the quartz component is mixed into the wafer as impurities, or the quartz tube is damaged during the deposition process.

Therefore, it is necessary to replace the quartz tube at regular intervals, and it is usually replaced every two months. Since the quartz tube is very expensive, there is a problem that equipment maintenance cost is greatly increased.

Therefore, in order to prevent contact between the silane gas and the quartz tube, a method of sealing the space between the quartz tube and the silicon carbide tube was also considered, but it is difficult to find a material that can withstand high temperatures while completely sealing is not easy. In particular, there is a problem in which it is very difficult to deduce a method to enable repetitive sealing and release of the sealing.

Korean Patent Registration No. 10-1389845 Korean Patent Publication No. 10-2003-0090726

The present invention was conceived to solve the above-described problem, and the present invention prevents degeneration of the quartz tube by essentially blocking the contact between the quartz tube and the silane gas by flowing nitrogen gas into the space between the silicon carbide tube and the quartz tube. Therefore, it aims to extend the service life of the quartz tube.

In addition, another object of the present invention is to allow a greater amount of silane gas to be used for wafer deposition by allowing the silane gas to flow only inside the silicon carbide tube, thus improving the efficiency of use of the silane gas.

In order to achieve the above object, the present invention is a tube structure of a deposition equipment for semiconductor manufacturing, comprising: a silicon carbide tube, which is a region in which silicon is deposited by supplying a silane gas onto a semiconductor wafer mounted therein; A quartz tube surrounding the silicon carbide tube so as to have a wider diameter compared to the silicon carbide tube and to provide a space between the silicon carbide tube; First and second door portions provided at both ends of the silicon carbide tube and the quartz tube, at least one end configured to be openable and closed to hermetically close the both ends; A silane gas supply pipe provided on one side of the first door and supplying silane gas into the silicon carbide pipe; A nitrogen gas supply pipe provided on another side of the first door and supplying nitrogen gas between at least the silicon carbide pipe and the quartz pipe; wherein the nitrogen supplied through the nitrogen gas supply pipe is between the silicon carbide pipe and the quartz pipe It provides a structure for preventing contact with silane gas of a quartz tube for wafer deposition, characterized in that it is introduced into the space of and flows into the silicon carbide tube.

The nitrogen gas is preferably supplied not only between the silicon carbide tube and the quartz tube but also inside the quartz tube.

When the nitrogen gas is supplied into the quartz tube, it is preferable that the nitrogen gas is supplied to flow in a direction opposite to the flow direction of the silane gas to prevent the silane gas from flowing through the quartz tube.

The nitrogen gas is preferably supplied at a flow rate per unit time of at least 500 to 1,500 cc/min while supplying the silane gas.

Among the nitrogen gas, nitrogen gas flowing between the silicon carbide tube and the quartz tube is supplied to the quartz tube through the gap between the door part configured to communicate with the quartz tube and the silicon carbide tube, and goes to the outside together with the residual silane gas after the deposition process. It is desirable to be discharged.

An end of the nitrogen gas supply pipe is connected to a branch pipe, and at least two nozzles are connected to each end of the branch pipe, and one of the nozzles is arranged to face between the silicon carbide pipe and the quartz pipe, and the other is carbonized. It is preferable that it is arranged to face the inside of the silicon tube.

According to the present invention as described above, nitrogen gas is flowed into the space between the silicon carbide tube and the quartz tube to prevent the quartz tube from being denatured by fundamentally blocking the contact between the quartz tube and the silane gas, thus reducing the service life of the quartz tube. You can expect the effect of extending it.

In addition, by allowing the silane gas to flow only inside the silicon carbide tube, a larger amount of the silane gas can be used for wafer deposition, and thus an effect of improving the utilization efficiency of the silane gas can be expected.

1 is a schematic diagram showing the appearance of a semiconductor wafer deposition apparatus.
2 is a view showing an arrangement of a quartz tube and a silicon carbide tube in a semiconductor wafer deposition apparatus.
3 is a view showing various configurations including a silane gas and nitrogen gas inlet pipe provided on a door according to an embodiment of the present invention;
4 is a gas flow chart showing the flow of silane gas when only silane gas is supplied;
5 is a gas flow diagram showing the flow of nitrogen gas and silane gas when nitrogen gas and silane gas are supplied according to an embodiment of the present invention.
6 is a view showing a branch pipe further displayed in FIG. 5.

Hereinafter, the present invention will be described in more detail based on the accompanying drawings and preferred embodiments. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the subject matter of the present invention, a detailed description thereof will be omitted.

In the description of the present invention, the defined terms are defined in consideration of functions in the present invention, which may vary according to the intention or custom of a technician engaged in the relevant field, so the definition is based on the contents throughout the present specification. It will have to be lowered.

In the present invention, in order to express it separately from liquid nitrogen, it is expressed as nitrogen gas instead of nitrogen.

1 is a schematic diagram showing a semiconductor wafer deposition apparatus 100, FIG. 2 is a view showing the arrangement of the quartz tube 111 and the silicon carbide tube 112 in the semiconductor wafer deposition apparatus 100, FIG. It is a view showing various configurations including a silane gas and a nitrogen gas inlet pipe provided in the door part 120 according to an embodiment.

As shown, the semiconductor wafer deposition apparatus 100 to which the present invention is applied is a LPCVD (Low Pressure CVD) apparatus, and the apparatus is a reaction unit 110 made of a tube (silicon carbide tube 112) loaded with a semiconductor wafer. ) After lowering the internal pressure, the reaction gas (for example, silane [SiH ₄ ] gas) is flowed into the reaction unit 110 and the heater surrounding the reaction unit 110 is heated to give activity to the reaction gas. It is a device that performs a deposition process to form a desired material (Si) on the wafer surface.

The semiconductor wafer deposition apparatus 100 may have some differences in its shape or configuration for each manufacturer, but generally, a quartz tube 111 and a silicon carbide tube 112 (SiC tube) are provided in the housing. It is continuously charged, and a heater is provided on the outer periphery of the quartz tube 111, and the silicon carbide tube 112 has a smaller diameter than the quartz tube 111, so that the quartz tube 111 and the inside of the quartz tube 111 are generally It is disposed concentrically, and thus a predetermined space is provided between the quartz tube 111 and the silicon carbide tube 112. In addition, the door part 120 may be opened and opened in the housing so that the semiconductor wafer can be loaded into the silicon carbide tube 112 and closed so that the reaction is performed in a closed space. The door part 120 may be provided with a cooling water pipe 131 (PCW line), a vacuum tube for forming and maintaining a vacuum in the tube, an inlet for injecting a reaction gas, and an outlet for discharging the reaction gas. A gas pressure sensor capable of measuring gas pressure is provided on one side of the vacuum tube, so that the vacuum state can be monitored. In addition, the injected silane gas and/or the appropriate pressure of the silane gas and nitrogen gas can be checked.

Door portions 120 are provided at both ends of the semiconductor wafer deposition apparatus 100, and the door portion 120 implements a function as a door and a sealing function at the same time. At least one of them is configured to be openable and closed. The reason why the door unit 120 is configured to be openable and closed is as described above. When the door unit 120 is closed, an airtight state is implemented to maintain a vacuum state in the device.

The door portions 120 provided at both ends of the semiconductor wafer deposition apparatus 100 may be used as the first door portion 121 and the second door portion 122, respectively, and if the reaction gas injection hole is in the first door portion 121 (124) is provided, a nitrogen inlet (123) is provided next to it, and a reaction gas outlet (not shown) corresponding thereto is provided in the second door part (122) or discharged through the gas outlet (126). I can. Here, since an injection hole may be provided in the first door part 121 or an injection hole may be provided in the second door part 122, the door part 120 in which the injection hole is provided may be used as any one of the door parts 120. It is not limited.

4 is a gas flow diagram showing the flow of silane gas when only silane gas is supplied, and FIG. 5 is a flow diagram showing the flow of nitrogen gas and silane gas when nitrogen gas and silane gas are supplied according to an embodiment of the present invention. Gas flow diagram.

As shown in FIG. 4, the silane gas is injected into the silicon carbide tube 112 in which a plurality of semiconductor wafers are loaded through a gas inlet connected to the silane gas tank and deposited on the semiconductor wafer, and then the residual gas is discharged through the outlet. Is discharged. Here, a space is provided between the silicon carbide pipe 112 and the door part 120, and this space communicates with the space between the silicon carbide pipe 112 and the quartz pipe 111. However, in reality, it is not easy to derive a method for sealing this space as a way to block such a communication structure. For example, if a rubber O-ring is used, it cannot withstand high temperatures, and if it is not made of rubber, proper sealing cannot be achieved unless it is permanently sealed.

Here, the necessity of sealing depends on the gist of the present invention. That is, as described above, when the quartz tube 111 repeatedly contacts the silane gas, the silicon (Si) layer formed inside the quartz tube 111 promotes the deterioration of the quartz tube 111, and the silicon layer becomes quartz The characteristic of the tube 111 is changed, or a difference in thermal expansion coefficient occurs between the inside of the quartz tube 111 in which the silicon layer is formed and the outside in which the silicon layer is not formed, and during the repeated heat treatment process according to the difference in the thermal expansion coefficient. Cracks or breakage may occur in the quartz tube 111.

Therefore, by preventing the silane gas and the quartz tube 111 from contacting each other, the life of the quartz tube 111 can be increased by 2 to 6 times, which is a repetitive deposition process for the production of polycrystalline silicon for solar power. Therefore, the increase in durability and life of the quartz tube 111 becomes an important factor in reducing the cost of producing deposited silicon.

Accordingly, in the present invention, it is determined that sealing is impossible, and as an alternative, nitrogen gas is pre-injected into the space 113 between the silicon carbide tube 112 and the quartz tube 111, and the flow is maintained. Subsequently, by injecting the silane gas, the movement of the silane gas from the silicon carbide tube 112 to the inside of the quartz tube 111 was suppressed due to the flow of nitrogen gas. That is, by making the flow direction of the nitrogen gas opposite to the inflow direction of the silane gas, the contact of the silane gas with the quartz tube 111 was fundamentally blocked. In FIG. 5, the solid line represents silane gas, and the dotted line represents nitrogen gas. In order to block the inflow of silane gas into the quartz tube 111, nitrogen gas must be injected first at a time difference, and only when the nitrogen gas atmosphere is sufficiently formed, silane gas is injected into the tube.

As shown in FIG. 5, the nitrogen gas flows through the space 113 between the quartz tube 111 and the silicon carbide tube 112, but may also flow inside the silicon carbide tube 112, and nitrogen gas is a silane gas. As it does not react with, there is no effect on the deposition process by silane gas. If the gas is not nitrogen gas and does not react with silane gas, the gas can replace nitrogen gas.

In addition, the nitrogen gas performs a deposition process on the wafer and guides the remaining silane gas so that it can be discharged smoothly. In addition, since the deposition area of the silane gas is limited to the silicon carbide tube 112 due to the nitrogen gas, the utilization efficiency of the silane gas can be further increased.

The remaining silane gas used in the deposition process may be discharged together with nitrogen gas and then recovered for recycling.

The flow of nitrogen gas will be described in more detail as follows.

The flow direction of the nitrogen gas may be any direction to prevent the silane gas from flowing into the quartz tube 111, but if possible, the silicon carbide tube (in the space between the door 120 and the silicon carbide tube 112) 112) It is desirable to be supplied to flow inside. When nitrogen is injected from one side of the first door 121 among the door parts 120 provided at both ends of the quartz tube 111, the injected nitrogen gas flows between the quartz tube 111 and the silicon carbide tube 112. It diverges into the first flow and the second flow directly flowing into the silicon carbide pipe 112, and the second flow prevents silane gas from flowing into the quartz pipe 111 through the space formed near the first door part 121 And, since the first flow flows into the silicon carbide pipe 112 through the space formed near the second door part 122, the inflow of silane gas through the space formed near the second door part 122 is prevented. .

In addition, it is preferable that the nitrogen gas is configured to flow in and out through any one of the door parts 120. That is, if nitrogen gas is introduced through the first door part 121, it is preferable to discharge nitrogen gas through the second door part 122, and at this time, various injection reservoirs of the second door part 122 Alternatively, by making all the outlets completely closed, the nitrogen gas can be completely controlled so as to sufficiently form an atmosphere in the pipe. Meanwhile, one nitrogen gas inlet is sufficient, but may be more than that.

On the other hand, in the present invention, the flow rate of nitrogen gas supplied per unit time should be considered. Because the silane gas is decomposed and deposited, the optimum conditions should be presented so that it should not interfere with the deposition and the sealing role for the silane gas should be fulfilled. Because. Therefore, when the nitrogen gas flow rate per unit time of 500 ~ 1,500 cc/min is presented for the supply of silane gas required to perform the deposition process, the above condition is secured, and thus the flow rate per unit time of the nitrogen gas is critical. It is meaningful.

In addition, nitrogen gas is preferably injected into the region so as to flow between the silicon carbide tube 112 and the quartz tube 111, but not only between the silicon carbide tube 112 and the quartz tube 111, but also the silicon carbide tube 112 ) It is preferable to use the branch pipe 130 so that the gas is also injected inside. That is, it is preferable that one of the nozzles of the branch pipe 130 faces between the silicon carbide pipe 112 and the quartz pipe 111 and the other one faces the inside of the silicon carbide pipe 112. This branch pipe 130 is represented in FIG. 6.

In this way, nitrogen gas is continuously flowed in the region between the quartz tube 111 and the silicon carbide tube 112 for a period of time longer than the time that the silane gas flows, thereby allowing the silane gas to come into contact with the quartz tube 111. It can be fundamentally blocked, thereby avoiding the crack of the quartz tube 111, it is possible to provide an opportunity to use for a longer period of time.

Although the present invention has been described in more detail by way of examples above, the present invention is not necessarily limited to these embodiments, and various modifications may be made without departing from the spirit of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain it, and the scope of the technical idea of the present invention is not stabilized by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

100: semiconductor wafer deposition apparatus 110: reaction unit
111: quartz tube 112: silicon carbide tube
120: door part 121: first door part
122: second door part 123: nitrogen injection port
124: reaction gas inlet 126: gas outlet
127: pressure sensor 129: pedestal
130: branch pipe 131: cooling water pipe

Claims (6)

As a tubular structure of deposition equipment for semiconductor manufacturing,
A silicon carbide tube, which is a region through which silicon is deposited by supplying a silane gas onto a semiconductor wafer mounted therein;
A quartz tube surrounding the silicon carbide tube so as to have a wider diameter compared to the silicon carbide tube and to provide a space between the silicon carbide tube;
First and second door portions provided at both ends of the silicon carbide tube and the quartz tube, at least one end configured to be openable and closed to hermetically close the both ends;
A silane gas supply pipe provided on one side of the first door and supplying silane gas into the silicon carbide pipe;
A nitrogen gas supply pipe provided on another side of the first door and supplying nitrogen gas between at least the silicon carbide pipe and the quartz pipe;
Including, wherein the nitrogen supplied through the nitrogen gas supply pipe is introduced into the space between the silicon carbide pipe and the quartz pipe and flows into the silicon carbide pipe.
Silane gas contact prevention structure of the quartz tube for wafer deposition. The method of claim 1,
The nitrogen gas is supplied not only between the silicon carbide tube and the quartz tube but also inside the quartz tube. The method of claim 2,
When the nitrogen gas is supplied into the quartz tube, it is supplied to flow in a direction opposite to the flow direction of the silane gas to prevent the silane gas from flowing into the quartz tube. . The method of claim 2,
The nitrogen gas is supplied at a flow rate per unit time of at least 500 to 1,500 cc/min while the silane gas is supplied. The structure for preventing contact with silane gas of a quartz tube for wafer deposition, characterized in that. The method of claim 1,
Among the nitrogen gas, nitrogen gas flowing between the silicon carbide tube and the quartz tube is supplied to the quartz tube through the gap between the door part configured to communicate with the quartz tube and the silicon carbide tube, and goes to the outside together with the residual silane gas after the deposition process. Silane gas contact prevention structure of the quartz tube for wafer deposition, characterized in that discharged. The method of claim 1,
An end of the nitrogen gas supply pipe is connected to a branch pipe, and at least two nozzles are connected to each end of the branch pipe, and one of the nozzles is arranged to face between the silicon carbide pipe and the quartz pipe, and the other is carbonized. Silane gas contact prevention structure of the quartz tube for wafer deposition, characterized in that arranged to face the inside of the silicon tube.

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