JPH03151633A - Heat-treating furnace for semiconductor wafer - Google Patents

Abstract

PURPOSE:To prevent oxygen gas from permeating by mistake when hydrogen gas is present, by opening and shutting the opening part of a furnace core tube main body, and selecting the gas to be supplied to the furnace core tube main body in accordance with detected results of total gas pressure of exhaust gas, partial pressure of hydrogen, and partial pressure of oxygen discharged from the furnace core tube main body. CONSTITUTION:Partial pressure of hydrogen, partial pressure of oxygen, and total gas pressure of the exhaust gas discharged from a furnace core tube main body 21 are detected by a detecting equipment 81. In accordance with the partial pressure of hydrogen, the partial pressure of oxygen, and the total gas pressure detected by the detecting equipment 81, a first control signal, a second control signal, and a third control signal are generated, respectively. In accordance with a first control signal, a furnace lid 71 arranged at an open end portion 218 of the furnace core tube main body 21 is opened and shut by a driving equipment 74. In accordance with the second and the third control signals, gas to be supplied to the internal space 21A of the furnace core tube main body is controlled by a gas selecting equipment 23. Thereby oxygen gas can be prevented from permeating by mistake when hydron gas is present, and the hydrogen gas can be immediately eliminated when an accident like the generation of cracks occurs in the furnace core tube main body.

Description

Detailed Description of the Invention (11) Object of the Invention [Field of Industrial Application] The present invention relates to a heat treatment furnace for semiconductor wafers, and particularly relates to a heat treatment furnace for semiconductor wafers. The present invention relates to a heat treatment furnace for semiconductor wafers, which opens and closes an opening of a furnace core tube body and selects a gas to be supplied to the furnace core tube body according to the results of detecting oxygen partial pressure and oxygen partial pressure.

[Prior Art] Conventionally, in this type of semiconductor wafer heat treatment furnace, for example, a furnace is placed on a furnace lid body in an internal space of a furnace core tube body surrounded by a soaking tube, a heating member, and a heat insulating tube. A heat treatment furnace for semiconductor wafers has been proposed, in which a semiconductor wafer is housed in a supported state in a wafer heat treatment jig, and then an appropriate heat treatment is performed on the semiconductor wafer by supplying an appropriate heat treatment gas.

[Problems to be solved] However, in conventional semiconductor wafer heat treatment furnaces,
When hydrogen gas is used as a heat treatment gas, there is a drawback that (il) if the opening of the furnace core tube body is incompletely sealed, oxygen gas will enter the internal space of the furnace core tube body, and (ii) When the semiconductor wafer enters and exits the furnace core tube body, the internal space of the furnace core tube body is incompletely scavenged by an inert gas (nitrogen gas, etc.), and the opening of the furnace core tube body is opened with hydrogen gas remaining. As a result, oxygen gas and hydrogen gas react with each other in the internal space of the furnace core tube body, resulting in an explosion.

Therefore, in order to eliminate these drawbacks, the present invention aims to control the opening of the furnace core tube body according to the results of detecting the total gas pressure, hydrogen partial pressure, and oxygen partial pressure of the exhaust gas discharged from the furnace core tube body. It is an object of the present invention to provide a heat treatment furnace for semiconductor wafers in which the supply gas to the furnace core tube body can be selected by opening and closing the parts.

(2) Structure of the invention [Means for solving the problems] The means for solving the problems provided by the present invention is that the inner space of the furnace core tube body is surrounded by the r heating member and supplied with hydrogen gas as a heat treatment gas. On the other hand, in a semiconductor wafer heat treatment furnace in which the semiconductor wafer is heat-treated by closing the open end of the furnace core tube body with a furnace lid while the semiconductor wafer is supported and housed in a wafer heat treatment jig, a detection device for detecting the hydrogen partial pressure, oxygen partial pressure, and total gas pressure of the exhaust gas discharged from the pipe body; a control circuit for respectively generating first to third control signals in accordance with the lcl first control signal; and a drive device for opening and closing the furnace lid disposed at the open end of the furnace core tube body in response to the lcl first control signal. and a gas selection device for selecting a gas to be supplied to the internal space of the furnace core tube body in accordance with +d+second and third control signals.'' be.

[Function] The heat treatment furnace for semiconductor wafers according to the present invention supports the semiconductor wafer on a wafer heat treatment jig in the inner space of the furnace core tube body, which is surrounded by a heating member and supplied with hydrogen gas as a heat treatment gas. This is a heat treatment furnace for semiconductor wafers, in which semiconductor wafers are heat-treated by closing the open end of the furnace core tube body with a furnace lid while the semiconductor wafer is housed in the furnace. The hydrogen partial pressure, oxygen partial pressure, and total gas pressure of A second control signal is generated, and a drive device opens and closes a furnace lid disposed at the open end of the furnace core tube body in accordance with the first control signal. Third
Since the gas to be supplied to the internal space of the furnace core tube body is selected by the gas selection device according to the control signal of (ii) If an abnormality such as a crack occurs in the furnace core tube body, it immediately removes hydrogen gas, and (iii) It acts to prevent explosion accidents caused by the reaction between hydrogen gas and oxygen gas in the internal space.

[Example] Next, a preferred example of the heat treatment furnace for semiconductor wafers according to the present invention will be specifically described with reference to the accompanying drawings. However, the examples described below are described to facilitate or accelerate understanding of the present invention, and are not described to limit the present invention. In other words, each member disclosed in the embodiments described below includes all design changes and equivalent substitutions that fall within the spirit and technical scope of the present invention.

Figure 1 is a sectional view showing an embodiment of a semiconductor wafer heat treatment furnace according to the present invention, and in particular, a vertical heat treatment furnace l.
0, and shows a state in which the open end 21A of the furnace core tube body 21 is closed by the furnace lid body 71.

First, the structure of an embodiment of a heat treatment furnace for semiconductor wafers according to the present invention will be described in detail with reference to FIG. In FIG. 1, a vertical heat treatment furnace is illustrated as a heat treatment furnace for semiconductor wafers according to the present invention in order to simplify the following explanation, but there is no intention to limit the present invention to this.

Reference numeral 10 denotes a vertical heat treatment furnace for semiconductor wafers according to the present invention, which is provided as desired at an appropriate interval between a furnace core tube device side for heat-treating semiconductor wafers and around the furnace core tube device side. There is a heat soaking tube 30 to make it easy to secure a heat soaking area in the furnace core tube device. A heating member 40 for heating the furnace core tube device through the heating member 40, and a heat insulating pipe structure disposed around the heating member 40 to prevent the heat generated by the heating member 40 from escaping to the outside environment. and a housing made of a suitable material such as stainless steel to hold the furnace core tube device or the heat insulating tube 50, and the opening of the furnace core tube device is closed to isolate the internal space 21A from the outside environment. Furnace lid device 4, furnace core tube device 20, and furnace lid device 70 for
The heat treatment gas supplied to the furnace core tube device 20 is adjusted according to the exhaust gas discharged from the furnace lid device 70, and the control signal required for raising and lowering the furnace lid device 70 is provided. It also includes a control circuit 80 for generating the signal.

The furnace core tube device is made of a suitable material such as quartz, and includes a furnace core tube main body 21 for heat-treating semiconductor wafers in a soaking area formed in an internal space 21A, and a furnace core tube body 21 from the outside of a heat insulating tube 50. It is extended to the outer peripheral surface of the core tube body 21, and then extended along the outer peripheral surface of the furnace core tube body 21 to the top, and is opened to the internal space 21A at the top, and is filled with a suitable heat treatment gas (for example, hydrogen gas) or Scavenging gas (
A gas supply pipe 22 for supplying nitrogen gas (for example, nitrogen gas) as a supply gas, and a control signal for controlling the supply gas that is provided to the gas supply pipe 22 and supplied to the internal space 21A of the furnace core tube body 21. A gas selection device 23 for selecting according to Sll+S, □ and an open end 2 of the furnace core tube body 21
1B and extends to the outside of the heat insulating pipe 50 for discharging used heat treatment gas or scavenging gas from the internal space 21A of the furnace core tube body 21 as exhaust gas to the outside. 24 and a support protrusion 25 formed on the circumferential surface of the open end 21B of the furnace core tube body 21 and supported by the housing 60.

It is preferable that the portions of the gas supply pipe 22 and the gas discharge pipe 24 located near the furnace core tube body 21 are each made of a material that can be used at high temperatures, such as quartz, as much as possible.

The soaking tube 30 is made of a suitable material such as silicon carbide, and is arranged so as to surround the entire length of the furnace tube device 20 in order to secure or expand a heating area comparable to that of the furnace tube device.

The heating part material is disposed outside of the soaking tube, and is appropriately arranged in order to form and secure a soaking area along the axial direction in the internal space 21A of the furnace core tube device. There is.

The heat insulating tube 50 is made of a suitable heat insulating material such as glass fiber, and is connected to the furnace core tube device 20. The soaking tube 30 and the heating member 40 are completely surrounded.

The housing includes a support member main body 61 for supporting the lower ends of the heat soaking tube recess and the heat insulation pipe on the upper surface, and is attached to the lower surface of the support member main body 61 and has a central opening 62a.
A furnace tube body support member 62 for supporting the lower surface of the support protrusion 25 formed around the open end 21B of the furnace tube body 21 by the step end surface of the furnace tube body support member 62; The groove is disposed in a groove formed on the circumferential surface of the stepped portion of the opening 62a, and is for sealing between the supporting protrusion 25 formed on the circumferential surface of the open end 21B of the furnace tube main body 21. The O-ring 63 is attached to the lower surface of the support member 61 and surrounds the furnace core tube body support member 62, and the furnace lid device is attached to the end surface of the open end 21B of the furnace tube body 21. An opening 64a is formed in the center to allow the furnace lid device to approach and separate, and captures the heat treatment gas or scavenging gas that leaks out as the furnace core tube body 21 opens and closes due to the lifting and lowering of the furnace lid device. and a gas exhaust pipe 65 which is opened at one end on the side surface of the gas trapping member 64 and discharges leaked gas captured by the gas trapping member 64 to the outside. .

Furnace lid device publication includes a furnace lid body 71 made of a high-purity material that can be used at high temperatures, such as quartz or silicon carbide, which is in direct contact with the end surface of the open end 21B of the furnace core tube body 21; A furnace lid holding member 72 made of a suitable material such as stainless steel for holding the furnace lid main body 71, and a lower surface of the furnace lid holding member 72 supported via an elastic member (not shown). The main body 71 is inserted into the opening 64 of the gas capture member 64.
a furnace lid moving member 73 for approaching and separating from the open end 21B of the furnace core tube main body 21 via the furnace lid moving member 73; and a driving device 74 disposed at one end of the furnace lid moving member 73.
A drive shaft 75 is driven according to a control signal S+s to move the furnace lid moving member 73 up and down, and the driving shaft 75 is disposed at one end of the furnace lid moving member 73 like the drive shaft 75 and moves the furnace lid. A guide shaft 76 for stabilizing the vertical movement of the member 73 and a top surface of the furnace lid holding member 72 when the upper surface of the furnace lid main body 71 is brought into contact with the lower end surface of the open end 21B of the furnace core tube body 21. Furnace core tube body support member 6
In order to ensure a seal between the furnace lid holding member 72 and the lower surface of the furnace lid holding member 72, the furnace lid holding member 72 includes an O-ring 77 disposed in a groove formed on the upper surface of the furnace lid holding member 72.

The control circuit 80 is disposed with respect to the gas exhaust pipe 24 and controls the oxygen partial pressure P contained in the exhaust gas. a gas pressure detection device 81 including an oxygen partial pressure sensor for measuring the hydrogen partial pressure Po, a hydrogen partial pressure sensor for detecting the hydrogen partial pressure Po, and a total gas pressure sensor for detecting the total gas pressure P of exhaust gas; , a control signal 5lllS1 that is connected to the gas pressure detection device 81 and controls the gas selection device 23 according to the detection results (i.e., oxygen partial pressure P., hydrogen partial pressure P, and total gas pressure P).
2 and another control signal S + for controlling the drive device 74
s and a control circuit 82 for generating s.

Last month, we further described an embodiment of the heat treatment furnace for semiconductor wafers according to the present invention, with reference to the vertical heat treatment furnace illustrated in FIG. 1 and Table 1. The action will be explained in detail.

- Gas - The gas control circuit 82 first maintains the control signal S11 at a low level while controlling the The signal S12 is set to high level.

The gas selection device 23 starts supplying nitrogen gas in response to the control signal SI2 becoming high level.

The nitrogen gas is guided by the gas supply pipe 22 as shown by arrow A, and then is supplied from the top of the furnace tube body 21 toward the internal space 21A thereof.

The nitrogen gas supplied to the internal space 21A of the furnace core tube body 21 moves within the internal space 21A as shown by arrow B, and then is guided toward the gas exhaust pipe 24 as shown by arrow C. Along with this, the internal space 21A of the furnace core tube body 21
The residual gas (for example, hydrogen gas) that was filled in the gas exhaust pipe 24 is scavenged toward the gas exhaust pipe 24.

Nitrogen gas and hydrogen gas are discharged to the outside of the furnace core tube body 21 by the gas discharge pipe 24 as shown by the arrow.

As the scavenging of hydrogen gas by nitrogen gas progresses, the hydrogen partial pressure PH detected by the gas pressure detection device 81 gradually decreases.

When the internal space 21A of the furnace core tube main body 21 is filled with nitrogen gas, the hydrogen partial pressure P becomes smaller than the reference hydrogen partial pressure PH. Correspondingly, the control circuit 82 sets the control signal S+3 to a high level for a predetermined period.

The drive device 74 drives the drive shaft 75 in response to the control signal S13 becoming high level, thereby moving the furnace lid moving member 73 in the direction of arrow Y and lowering it to a predetermined position. , and move in the direction of arrow X to raise it to the initial position.

At this time, in the lowered position, the wafer heat treatment jig (not shown) holding the semiconductor wafer is moved to the furnace lid main body 7 held by the furnace lid moving member 73 by an appropriate work tool.
1, the semiconductor wafer to be heat-treated has been inserted into the internal space 21A of the furnace core tube body 21 when the furnace lid moving member 73 is raised to its original position.

3 pneumatic - responsible gas exhaust F7, the internal space 21A of the furnace core tube body 21 has its opening 21
Even after B is closed by the furnace lid main body 71, nitrogen gas continues to be supplied in order to scavenge oxygen gas that entered when inserting the wafer heat treatment jig. Thereby, the oxygen gas is gradually scavenged by the nitrogen gas through the gas exhaust pipe 24.

The control circuit 82 detects the oxygen partial pressure P detected by the gas pressure detection device 81. is the reference oxygen partial pressure P. The control signal S1□ is maintained at a high level as long as it exceeds the current value.

Therefore, the gas selection device 23 sets the oxygen partial pressure P. is the reference oxygen partial pressure P. Nitrogen gas is continued to be supplied to the internal space 21A of the furnace core tube body 21 until it becomes smaller than .

1 Gas - Nitrogen gas 7. Oxygen partial pressure P detected by gas pressure detection device 81
0 is the reference oxygen partial pressure P. 5 6 , the control circuit 82 sets the control signal S ++ to a high level and sets the control signal S1° to a low level.

The gas selection member 23 stops supplying nitrogen gas in response to the control signal S12 becoming low level, and then starts supplying hydrogen gas in response to the control signal S11 becoming high level. Start.

Hydrogen gas is guided by the gas supply pipe 22 as shown by arrow A, and then is supplied from the top of the furnace core tube body 21 toward its internal space 21A.

The hydrogen gas supplied to the internal space 21A of the furnace core tube body 21 moves in the internal space 21A as indicated by arrow B (after moving as indicated by arrow C) and is guided toward the gas exhaust pipe 24 as indicated by arrow C. Accordingly, the internal space 21A of the furnace core tube body 21
Nitrogen gas that was filled in the gas discharge pipe 24 is scavenged toward the gas exhaust pipe 24.

Nitrogen gas and hydrogen gas are discharged to the outside of the furnace core tube body 21 by the gas discharge pipe 24 as shown by the arrow.

As the scavenging of the nitrogen gas by the hydrogen gas progresses, the hydrogen partial pressure PH detected by the gas pressure detection device 81 gradually increases.

The hydrogen partial pressure P□ detected by the heat treatment operating gas pressure detection device 81 is the reference hydrogen partial pressure P. After the total gas pressure P becomes greater than the reference total gas pressure P, the heat treatment operation for the semiconductor wafer is started.

That is, an appropriate heat treatment gas (for example, argon gas) starts to be supplied together with hydrogen gas from the gas selection device 23 to the internal space 21A of the furnace core tube body 21 via the gas supply pipe 22.

The semiconductor wafer held in the wafer heat treatment jig is thereby subjected to appropriate heat treatment in the internal space 21A of the furnace core tube body 21.

Here, the total gas pressure P detected by the gas pressure detection device 81 is larger than the reference total gas pressure P (the basis for maintaining this is that when an abnormality such as a crack occurs in the furnace core tube body 21, oxygen is supplied from the outside). The purpose is to prevent gas from entering.

5 gas - blue gas When the heat treatment operation for the remaining semiconductor wafer is completed, the supply of heat treatment gas from the gas selection device 23 to the internal space 21A of the furnace core tube body 21 is stopped, and if there is any abnormality such as a crack in the furnace core tube body 21, When this occurs, hydrogen gas leaks from the furnace core tube body 21, so that the total gas pressure P detected by the gas pressure detection device 81 becomes smaller than the reference total gas pressure P. In response, the control circuit 82 sets the control signal S ++ to a low level and sets the control signal S +t to a high level.

The gas selection device 23 stops supplying hydrogen gas in response to the control signal S becoming low level, and then starts supplying nitrogen gas in response to the control signal S12 becoming high level. do.

The nitrogen gas is guided by the gas supply pipe 22 as shown by arrow A, and then is supplied from the top of the furnace tube body 21 toward the internal space 21A thereof.

The nitrogen gas supplied to the internal space 21A of the furnace core tube body 21 moves within the internal space 21A as shown by arrow B, and then is guided toward the gas exhaust pipe 24 as shown by arrow C. Along with this, the internal space 21A of the furnace core tube body 21
The hydrogen gas that had been filling up is scavenged toward the gas exhaust pipe 24.

Nitrogen gas and hydrogen gas are discharged to the outside of the furnace core tube body 21 by the gas discharge pipe 24 as shown by the arrow.

As the scavenging of hydrogen gas by nitrogen gas progresses, the hydrogen partial pressure P detected by the gas pressure detection device 81 increases.

gradually decreases.

When the internal space 21A of the core tube main body 21 is filled with nitrogen gas, the hydrogen partial pressure P□ becomes smaller than the reference hydrogen partial pressure PH. Correspondingly, the control circuit 82 sets the control signal S +s to a high level for a predetermined period.

The drive device 74 moves the furnace lid moving member 73 in the direction of arrow Y and lowers it to a predetermined position by driving the drive shaft 75 in response to the control signal S+a becoming high level. , and move in the direction of arrow X to raise it to the initial position.

At its lowered position, the wafer heat treatment jig is lowered from the furnace lid main body 71 held by the furnace lid moving member 73 by an appropriate work tool, so that the heat-treated semiconductor wafers are transferred to the furnace core tube main body 21. This means that it has been taken out from the internal space 21A.

Modification Example 1 In the above description, the furnace lid 71, which is equivalent to a furnace lid device, is connected to the furnace core tube body 2.
Although the case has been described in which the opening end of the furnace lid device 2 is brought into direct contact with the end surface of the furnace lid device, the present invention is not limited to this. It also includes cases where it only abuts.

(3) Effects of the Invention As is clear from the above description, the heat treatment furnace for semiconductor wafers according to the present invention provides a heat treatment furnace for semiconductor wafers with respect to the inner space of the furnace core tube body, which is surrounded by the heating member and to which hydrogen gas is supplied as the heat treatment gas. A heat treatment furnace for semiconductor wafers, in which a semiconductor wafer is heat-treated by closing the open end of a furnace core tube body with a furnace lid while the wafer is supported and housed in a wafer heat treatment jig, and in particular, the furnace The hydrogen partial pressure, oxygen partial pressure, and total gas pressure of the exhaust gas discharged from the core tube body are detected by a detection device, and the hydrogen partial pressure, oxygen partial pressure, and total gas pressure detected by the detection device are detected. Each of the control circuits generates first to third control signals, the drive device opens and closes the furnace lid disposed at the open end of the furnace core tube body in response to the first control signal, and the second. Third control example Since the gas to be supplied to the internal space of the furnace tube body is selected by the gas selection device according to the control signal, (1) Hydrogen gas is present in the internal space of the furnace tube body. It has the effect of preventing oxygen gas from entering accidentally during the period, and also has the effect of immediately removing hydrogen gas even if an abnormality such as a crack occurs in the FIII furnace core tube body. This has the effect of preventing explosion accidents caused by the reaction between hydrogen gas and oxygen gas in the internal space of the core tube body.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a semiconductor wafer heat treatment furnace according to the present invention. IO... ... ... Vertical heat treatment furnace 20
・・・・・・・・・・・・ Furnace core tube device 21 ・
・・・・ ・Furnace core tube body 21A ・・
...Internal space 21B... ...Open end 22... ...Gas supply pipe 23...
...... Gas selection device 24...
......Gas exhaust pipe 25......
・・・・Support protrusion 30 ・・・・・・・・・・・・・・ Soaking tube 40 ・・・・・・・・・・・・・・・ Heating member 50 ・・・・・......Insulated pipe 60
・Housing 61・・・・
......Supporting member body 62...
......Furnace core tube body support member 3 4 62a...Opening 63...O-ring 64.
...... Gas capture member 64a...
...... Opening 65 ...... Gas discharge pipe 70
......... Furnace cover device 71...
......... Furnace lid body 72...
...... Furnace lid holding member 73 ......
..... Furnace lid moving member 74 .....
Drive device 75...... Drive shaft 76
・・・・・・・・・・・・・・・Guide shaft 77...
・・・・・・・・・・・・O-ring 80・・・・・・
......Control device 81...
......Gas pressure detection device 82...
・Control circuit

Claims (1)

[Scope of Claims] A semiconductor wafer is supported and housed in a wafer heat treatment jig, and the furnace lid is used to open the inner space of the furnace core tube body, which is surrounded by a heating member and supplied with hydrogen gas as a heat treatment gas. In a heat treatment furnace for semiconductor wafers in which semiconductor wafers are heat-treated by closing the open end of the core tube body, (a) Hydrogen partial pressure, oxygen partial pressure, and total gas of exhaust gas discharged from the furnace core tube body. (b) a control circuit for generating first to third control signals in accordance with the hydrogen partial pressure, oxygen partial pressure, and total gas pressure detected by the detection device; (c) a drive device for opening and closing the furnace lid disposed at the open end of the furnace core tube body in response to the first control signal; (d) in response to the second and third control signals. A heat treatment furnace for semiconductor wafers, comprising a gas selection device for selecting a gas to be supplied to the internal space of a furnace core tube body.