JP2008108983A - Vapor phase growth apparatus and vapor phase growth method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor phase growth apparatus which can suppress deposition of a by-product generated from a process gas on an inner wall of a chamber after a vapor phase growth reaction, and also a vapor phase growth method. <P>SOLUTION: The vapor phase growth apparatus comprises a heater 113 for heating a low temperature part of a protection cover 102 provided within a chamber 101 as in the vicinity of an exhaust part 105, a temperature detection means 114 for detecting the temperature of the protection cover 102 or the heater 113, and a controller 115 for controlling the output of the heater 113. Cooling of a process gas after a vapor phase growth reaction causes a by-product to be suppressed from being deposited on an inner wall of the chamber 101. With it, a frequency of maintenance of disassembling the chamber 101 and removing the deposition therefrom and so on can be reduced and the process conditions upon the vapor phase growth reaction can be stabilized. Consequently, there can be provided a novel vapor phase growth method and apparatus which can manufacture a high quality of wafer with a high operating efficiency. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vapor phase growth (CVD: Chemical Vapor Deposition, including VPE: Vapor Phase Epitaxial grows), and more particularly, to a vapor phase growth apparatus and a vapor phase growth method for forming a film while rotating a semiconductor wafer. Regarding the method.

  FIG. 5 is a cross-sectional view of the structure of a conventional vapor phase growth apparatus, wherein 101 is a chamber, 102 is a protective cover that covers the inner wall of the chamber, 103a and b are cooling water flow paths for cooling the chamber, and 104 is a process gas. 105 is a process gas exhaust unit after reaction, 106 is a wafer for vapor phase growth, 107 is a susceptor that supports the wafer 106, and 108 is a heater that is supported by a support unit (not shown) and heats the wafer 106. 109 is a flange portion for connecting the upper and lower portions of the chamber 101, 110 is a packing for sealing the flange portion 109, 111 is a flange portion for connecting the exhaust portion 105 and the pipe, and 112 is a packing for sealing the flange portion 111.

  In the conventional general vapor phase growth apparatus described above, the wafer 106 is supported in the chamber 101 and heated to 1000 ° C. or more by the heater 108 while being rotated by the susceptor 107 provided with a rotation mechanism (not shown). In this state, a process gas including a reactive gas is supplied from the supply unit 104 into the chamber 101 to form a crystal film on the surface of the wafer 106. At this time, process gases other than those used in the vapor phase growth reaction are sequentially exhausted from an exhaust unit 105 provided in the lower portion of the chamber 101. At this time, a portion of the protective cover 102 in the vicinity of the exhaust portion 105 is away from the high temperature portion in the chamber 101 such as the wafer 106 and the heater 108 and is located at the lower portion of the chamber 101, so Hard to receive heat radiation and high temperature.

  Further, packings 110 and 112 are used for sealing the flange part 109 of the chamber 101 and the flange part 111 of the exhaust part 105. The packings 110 and 112 are made of fluoro rubber, and the heat resistant temperature is about 300 ° C. Therefore, flow paths 103a and 103b for circulating cooling water for preventing the packings 110 and 112 from being deteriorated by heat are provided on the outer periphery of the chamber 101. Although the cooling water cools the packings 110 and 112 through the chamber 101, the chamber 101 main body and the protective cover 102 are also cooled at the same time, so that a portion having a low temperature is formed in the vicinity of the exhaust part 105 in the chamber 101.

The problem here is that if the process gas after the reaction when dichlorosilane (SiH ₂ Cl ₂ ) is used as the reactive gas in the vapor phase growth reaction is exposed to a low temperature environment, the reactive polycrystal of the byproduct is present. Siloxane (chemical formula Si _x H _{2x + 2-y} Cl _y where y ≦ 2x + 2) is generated and deposited. For the production of high quality wafers such as the flow rate and flow rate of the process gas required for the vapor phase growth reaction and the exhaust pressure of the exhaust unit 105 increase by depositing by-products near the exhaust unit. Various problems occur that make it impossible to meet the required process conditions.

Further, when it becomes difficult to set process conditions in the chamber 101 due to the generation of deposits, the chamber 101 is disassembled by removing the flange portion 109, and maintenance such as internal cleaning depends on operating conditions. Approximately once a month. In addition, even if the device is reassembled as it was after completing this maintenance work, seasoning (withering) is necessary to return the quality of the produced wafer crystals, such as the film thickness and purity, to the level before the maintenance work. Driving) time is required. Seasoning refers to an operation of repeating a film forming operation using a dummy wafer in order to eliminate moisture and metal contamination until the chamber is ready for production operation.
When the frequency of the maintenance work is high, the operating rate of the vapor phase growth apparatus due to this decreases.
As described above, in the conventional vapor phase growth apparatus, the maintenance inside the chamber 101 and the apparatus after the maintenance, in which the maintenance of the quality of the wafer to be manufactured is hindered because the by-product deposition inside the chamber 101 cannot satisfy the process conditions. There is a problem that the management of the system increases, and the operating rate of the apparatus decreases.

  In the above-described vapor phase growth apparatus, it is desired that the process conditions in the chamber 101 are not always satisfied due to deposition of by-products.

Further, for example, as disclosed in Japanese Patent Application Laid-Open No. 2001-226774 (Patent Document 1), the temperature inside the exhaust pipe, which is connected to the exhaust part of the chamber and is easy to deposit by-products, is controlled or inactive. A flow layer of gas (for example, N ₂ ) is created near the surface of the inner tube of the exhaust pipe, and the process gas after the reaction is not exposed to the surface of the inner tube of the exhaust pipe so as to suppress the accumulation of by-products and thereby try to smooth the exhaust. That is common.

However, no matter how much the portion of the exhaust path after the exhaust pipe is cleaned, deposition of by-products in the chamber is a problem that occurs in the method of Patent Document 1 as well. Maintenance must be performed to remove by-products deposited on the substrate.
JP 2001-226774 A

As described above, as in the conventional vapor phase growth apparatus, by suppressing the generation of by-products in the exhaust pipe outside the chamber, the by-products are deposited inside the chamber, so that the process conditions in the chamber cannot be satisfied. Falls into the system, and the operating rate of the apparatus decreases. Therefore, the problem of affecting the quality and productivity of the manufactured wafer has not been solved.
The present invention addresses the above-mentioned points, improves the operating rate of the vapor phase growth apparatus by suppressing the generation of by-products during vapor phase growth in the chamber, and sets the process conditions during the vapor phase growth reaction. A novel vapor phase growth apparatus and vapor phase growth method capable of manufacturing a high-quality wafer at a high operating rate in a stable manner are provided.

  The feature of the vapor phase growth apparatus of the present invention is that a chamber having a supply part for introducing a process gas and an exhaust part for exhausting the process gas after reaction, a protective cover for covering the inner wall of the chamber, and a temperature at which the protective cover is set A first heater for heating the substrate, a temperature detecting means for detecting the temperature of the first heater or the protective cover, a cooling means provided on the outer periphery of the chamber, and a wafer for vapor phase growth provided in the chamber. A rotatable susceptor for supporting and a second heater for heating the wafer are provided, and the first heater and the temperature detecting means are provided in the vicinity of the exhaust portion of the protective cover.

  In the present invention, the first heater is covered with a protective cover.

  Further, in the present invention, the first heater is connected to a controller for controlling the output of the heater based on the temperature detected by the temperature detecting means.

  Furthermore, in the present invention, the temperature detecting means is covered with a protective cover.

In addition, the method of the present invention is characterized by forming a crystal film on the wafer surface by heat-treating the wafer in a process gas atmosphere in the chamber while cooling the chamber, and exhausting the reacted process gas from the chamber. In the vapor phase growth method,
A first step in which temperature detection means covered with a protective cover covering the inner wall of the chamber detects the temperature of the heater or the protective cover;
A second step in which a controller connected to the heater controls the output of the heater based on the temperature information detected by the temperature detection means so that the temperature of the protective cover is set;
It is in having.

  According to the present invention, by suppressing the generation of by-products during vapor phase growth in the chamber, the operating rate of the vapor phase growth apparatus is improved and the process conditions during the vapor phase growth reaction are stabilized. It is possible to provide a novel vapor phase growth apparatus and vapor phase growth method capable of producing a high-quality wafer at a high operation rate.

The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

(Embodiment)
The vapor phase growth apparatus and the vapor phase growth method of this embodiment will be described in order with reference to FIGS. Further, the same parts as those of the conventional example shown in FIG.

For example, carrier gas: H ₂ is set to ₂₀ to 100 SLM (Standard Liter per Minutes), and reactive gas: dichlorosilane (SiH ₂ Cl ₂ ) is set to 50 sccm. (Standard
Cubic centimeter per minutes (standard cc per minute) to 2 SLM, and other dopant gases: diborane (B ₂ H ₆ ) or phosphine (PH ₃ ) are set to be added in a very small amount. When diborane is introduced as described above, a p-type conductivity film is formed, and when phosphine is introduced, an n-type conductivity film is formed. Then, the pressure in the chamber 101 is controlled to 1333 Pa to normal pressure, for example. The above conditions are satisfied and vapor phase growth is started.

In general, the inner wall of the chamber 101 of the vapor phase growth apparatus is entirely covered with a protective cover 102 so as not to expose a stainless steel casing. This is to prevent particles and metal contamination at the time of forming a crystal film on the surface of the wafer 106 or erosion of the stainless steel casing of the chamber 101.
The susceptor 107 that supports the wafer 106 is connected to a rotation mechanism via a susceptor support 107a.

  During the vapor phase growth reaction of the wafer 106 under the above-described process conditions, the heater 108 always heats the wafer 106 to 1000 ° C. or higher, so that the temperature in the chamber 101 is entirely increased by the radiant heat and approaches the heater 108. This is particularly noticeable at the location and the upper portion of the chamber 101 that is susceptible to heat radiation.

  If the temperature of the entire chamber 101 becomes too high, a packing 110 that seals the flange portion 109 of the chamber 101 and a packing 112 that seals the flange portion 111 that connects the exhaust portion 105 and the exhaust pipe. Deteriorate. The packings (including O-rings and the like) used here are made of fluororubber and the heat resistant temperature is about 300 ° C.

  At this time, in order to suppress the deterioration of the packings 110 and 112, the cooling water having the water temperature of about 20 ° C. is circulated through the cooling water flow paths 103a and 103b provided on the outer periphery and the lower portion of the chamber 101, thereby easily receiving heat radiation. 101 upper part, packing 110,112, etc. are cooled by the circulation of a cooling water, and are maintained at the temperature favorable for operation | movement of an apparatus. In addition, the cooling means at this time may be other than water and may be any means such as air that can effectively remove heat from the apparatus.

However, the protective cover 102 is made of a material that is difficult to be heated, such as quartz glass or ceramics, and is located at a lower portion of the chamber 101 that is further away from a high-temperature portion such as the heater 108 in the protective cover 102. For example, a part that is not easily affected by the radiant heat of the heater 108 is more strongly affected by the cooling water and becomes a low temperature part, and a by-product that causes a problem is generated. Specifically, a protective cover 102a that covers the wall near the exhaust portion 105 at the bottom of the chamber 101, a lower portion 102b, and a circular protective cover 102c that covers the inner and lower surfaces of the chamber 101 shown in FIGS. By cooling, a by-product due to the process gas after the vapor phase growth reaction is generated and deposited. By-products resulting from the process gas after the vapor phase growth reaction, the reactive a polysiloxane _{(Si x H 2x + 2-} y Cl y where y ≦ 2x + 2), their nature is generally 100 ° C. or less of the environment It is said that it is generated and deposited when the process gas after vapor phase growth is exposed to.

  In such a state, the cross-sectional area of the exhaust path formed between the protective covers 102a and 102b near the exhaust part 105 and the outer periphery of the susceptor 107 decreases, and the cross-sectional area of the exhaust port of the exhaust part 105 decreases. However, the flow rate and flow rate of the process gas necessary for the vapor phase growth reaction introduced into the chamber 101 change, the exhaust pressure of the exhaust unit 105 increases, and the process conditions necessary for the production of a high-quality wafer cannot be satisfied. .

  Moreover, the deposited reactive polysiloxane has a risk of ignition, explosion, and the like, and has a property of curing when exposed to the outside air. For this reason, careful work is required for removal during maintenance, and time is required. Therefore, it becomes a problem as a cause of a decrease in the operating rate of the device itself.

In order to solve this problem, the protective covers 102a, b, c are heated by the heaters 113a, b, c covered by the protective covers 102a, b, c. Further, the thermocouples 114a, b, and c are covered with the protective covers 102a, b, and c similarly to the heaters 113a, b, and c, respectively. The temperature of the heaters 113a, b, c is detected.
In addition, although the thermocouple was provided in the detection of the temperature at this time, you may employ | adopt a thermistor, a thermostat, etc. as long as it can detect temperature not only with a thermocouple.

  Further, since the heater 113 and the thermocouple 114 are covered with the protective cover 102 so as not to be exposed in the chamber 101, the heater 113 and the thermocouple 114 do not become a source of metal contamination or particles inside the chamber but are exposed to the process gas. Therefore, the temperature can be detected accurately.

  At this time, the controller 115 operates in order to suppress the accumulation of by-products on the protective cover 102 and to adjust the temperature of the protective cover 102 within a range that does not deteriorate the packings 110 and 112. The controller 115 is connected to a heater 113 and a thermocouple 114 provided on the protective cover 102, and controls the output so that the heater 113 has a set temperature based on temperature information detected by the thermocouple 114. The protective cover 102 is adjusted to fall within the range of 100 ° C to 200 ° C. Within this range, accumulation of by-products on the protective cover 102 can be suppressed, and there is no possibility that the packings 110 and 112 provided in the vicinity will be deteriorated.

FIG. 4 shows a flowchart of the vapor phase growth method of this embodiment.
While cooling the chamber 101, the wafer 106 is heated in a process gas atmosphere containing a reaction gas in the chamber 101 to form a crystal film on the surface of the wafer 106, and the process gas after the reaction is exhausted from the chamber 101. In the phase growth method,
The temperature detection means 114a, b, c covered with the protective covers 102a, b, c covering the inside of the chamber 101 is heated by the heaters 113a, b, c or the protective covers 102a, b, c, The temperature detection step (S101) for detecting the temperature of c, the controller 115 connected to the heaters 113a, b, c detects the temperature of the heaters 113a, b, c based on the temperature information detected by the temperature detection means 114a, b, c. A series of steps called a temperature control step (S102) for controlling the output to control the protective covers 102a, 102b, 102c so as to reach the set temperature is continuously repeated. According to this method, it is possible to suppress the deposition of by-products in the chamber 101 and to smoothly exhaust the process gas used for the vapor phase growth.

  As described above, the present invention suppresses the accumulation of by-products generated from the process gas after the reaction in the chamber, which has been a problem in the past, and reduces the maintenance work by reducing the frequency of maintenance. The operating rate of the apparatus can be improved. As a result, it is possible to produce high quality wafers by stabilizing the process conditions.

In the embodiment of the present invention, dichlorosilane was cited as a reactive gas as a process condition for the vapor phase growth reaction. However, when dichlorosilane is used from the experience of the inventors, silane (SiH ₄ ), trichlorosilane ( Compared to the case of using SiHCl ₃ ), it has been found that a larger amount of by-products are generated, and this example was taken up as an example in which the effect is most prominent.

  The maintenance frequency required when operating the apparatus for suppressing the accumulation of by-products by heating the low temperature part of the protective cover in the chamber of the present invention, and the conventional apparatus shown in FIG. When the frequency of maintenance required for the operation is compared, it depends on the operating conditions, but the device of the present invention needs to be carried out about once every three months, and the conventional device is carried out about once a month. Is required. Therefore, in the apparatus of the present invention, the frequency of maintenance work can be reduced to about one third.

  The present invention is not limited to the above-described embodiments, and can be variously modified and implemented without departing from the scope of the invention.

The cross-sectional schematic diagram of the vapor phase growth apparatus in embodiment of this invention. The plane schematic diagram which showed the chamber inner lower part in embodiment of this invention. The cross-sectional schematic diagram of the lower part in a chamber in embodiment of this invention. The flowchart which showed the vapor phase growth method of this invention. The cross-sectional schematic diagram which showed the conventional vapor phase growth apparatus typically.

Explanation of symbols

101 ... chambers 102a, b, c ... protective cover 103a, b ... cooling water flow path 104 ... supply part 105 ... exhaust part 106 ... wafer 107 ... susceptor 108 ... heater 109 ... flange part 110 ... packing 111 ... flange part 112 ... Packing 113a, b, c ... heaters 114a, b, c ... thermocouple 115 ... controller

Claims (5)

  A chamber having a supply section for introducing process gas, an exhaust section for exhausting the process gas after reaction, a protective cover for covering the inner wall of the chamber, and a first heater for heating the protective cover to a set temperature; A temperature detecting means for detecting the temperature of the first heater or the protective cover; a cooling means provided on the outer periphery of the chamber; and a rotatable means provided in the chamber for supporting a wafer for vapor phase growth. A vapor phase growth apparatus comprising: a susceptor; and a second heater for heating the wafer, wherein the first heater and the temperature detecting means are provided in the vicinity of the exhaust portion of the protective cover.   The vapor phase growth apparatus according to claim 1, wherein the first heater is covered with the protective cover.   2. The vapor phase growth apparatus according to claim 1, wherein the first heater is connected to a controller for controlling the output of the heater based on the temperature detected by the temperature detecting means.   2. The vapor phase growth apparatus according to claim 1, wherein the temperature detecting means is covered with the protective cover. In the vapor phase growth method of forming a crystal film on the wafer surface by heating the wafer in a process gas atmosphere in the chamber while cooling the chamber, and exhausting the process gas after the reaction from the chamber,
A first step in which a temperature detecting means covered with a protective cover covering the inner wall of the chamber detects a temperature of a heater for heating the protective cover or the protective cover;
A second step in which a controller connected to the heater controls the output of the heater based on temperature information detected by the temperature detecting means so that the temperature of the protective cover is set;
A vapor phase growth method comprising:

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