JPH01236616A - Heat-treatment method for semiconductor device - Google Patents

Abstract

PURPOSE:To make it possible to conduct a heat treatment in a stable manner by a method wherein a heat treatment same as the intrinsic heat treatment using a dummy objective heat treatment having thermal characteristics equal to the objective substance of heat treatment, and the intrinsic objective substance is heat-treated by confirming the stability of the temperature profile. CONSTITUTION:First, a heat treatment is conducted using a dummy objective substance of heating, and temperature of the objective substance 11 of heating is detected in a heat-treatment cycle using a temperature detecting means 16. Whether the difference between the temperature detected by the heat-treatment cycle of the prescribed number of times using a discriminating means 17 and the corresponding temperature detected in the cycle of heat treatment conducted before the above-mentioned heat treatment is within the prescribed value is discriminated. By repeating a heat treatment cycle, temperature profile becomes constant, and as the variation in the thermal history between the heat-treatment cycle is reduced, the intrinsic objective substance 11 is used when a judgement is given that the temperature difference became the prescribed value. As a result, the treatment of a thermal history can be conducted.

Description

[Detailed Description of the Invention] [Summary] Before performing the actual heat treatment, a similar heat treatment was performed using a dummy object to be heated that had the same thermal characteristics as the object to be heat treated, and it was confirmed that the temperature profile was stable. With regard to the heat treatment method that processes the original target object, we aim to provide a heat treatment method that can make the heat history the same in each heat treatment cycle and perform stable heat treatment. A heating control means that controls the temperature, and a transport side that controls the heat treatment cycle of the object to be heated in the heat treatment chamber? 1 [1 means, a temperature detection means for detecting the temperature of the heated object during each heat treatment cycle, a temperature detected by the temperature detection means in a predetermined number of heat treatment cycles, and a temperature detected in the previous heat treatment cycle. and a determination means for determining whether the difference from the corresponding temperature is below a certain value, and first repeats the heat treatment using a dummy heating object having thermal characteristics equivalent to the original heating object,
The present invention includes a semiconductor device heat treatment method for heat-treating a semiconductor device, which is an original object to be heated, when the determination means determines that the value is below a certain value.

[Industrial application field]

In the present invention, before performing the original heat treatment, the same heat treatment is performed using a dummy object to be heated that has the same thermal characteristics as the object to be heat treated, and the temperature profile is confirmed to be stable. It relates to a heat treatment method for treating objects.

[Prior art] ′ Conventionally, in the semiconductor device manufacturing process, oxide film formation,
Various heat treatments are performed to thermally diffuse impurities.

In devices that perform such heat treatment, the wafer, which is the object to be heated, is placed, for example, on a support stand, is carried into a heat treatment chamber controlled at a constant temperature, and is processed for several minutes or a relatively long time. It is.

By the way, in recent years, as the performance of semiconductor devices has improved, the depth of junctions has become shallower, even in bipolar transistors, MO3 type transistors, etc., and it is necessary to perform heat treatment in a short time to suppress thermal diffusion within a predetermined range. There is.

Such heat treatment is performed in a short time of about several seconds, and in a single wafer type heat treatment apparatus or the like, the heat treatment is performed so that the heat history is the same in each heat treatment cycle.

[Problem to be solved by the invention]

However, in conventional heat treatment equipment, the object to be heated and the support stand etc. are heated together in the heat treatment chamber, so the temperature of the support stand etc. varies depending on the number of heating cycles, and as a result, the temperature of the support stand etc. differs depending on the number of heating cycles. The cycles had different thermal histories. Since the heat treatment history is not the same in this way, there is a problem in that semiconductor characteristics etc. vary. For example, FIG. 4 is a diagram showing the variation in the current amplification factor (hrt) of a transistor with respect to the number of heat treatment cycles, where the horizontal axis is the number of Mutsu treatment cycles, and the vertical axis is the variation in the current amplification factor (hFt) as a percentage. As shown in the figure, as the number of heat treatment cycles increases,
It is shown that the variation in the current amplification factor gradually decreases and reaches a constant value after a predetermined number of heat treatment cycles (No). That is, when the number of heat treatment cycles is small, the variation in current amplification factor increases. Note that the number of heat treatment cycles (No.) described above differs depending on the support table, temperature setting conditions, and the like.

Therefore, an object of the present invention is to provide a heat treatment method that can make the heat history the same in each heat treatment cycle and perform stable heat treatment.

[Means to solve the problem]

The above-mentioned problems include a heating control means for controlling the temperature of a heat treatment chamber, a transfer control means for controlling the heat treatment cycle of the object to be heated in the heat treatment chamber, and a temperature sensor for detecting the temperature of the object to be heated during each heat treatment cycle. and a determining means for determining whether the difference between the temperature detected by the temperature detecting means in a predetermined number of heat treatment cycles and the corresponding temperature detected in the previous heat treatment cycle is equal to or less than a certain value. Using the apparatus, first repeat the heat treatment using a dummy heating object that has the same thermal characteristics as the original heating object, and when the discrimination means determines that the temperature is below a certain value, the object is the original heating object. The problem is solved by a method of heat treatment of a semiconductor device, which is characterized by subjecting the semiconductor device to heat treatment.

[For production]

That is, in the present invention, first, a dummy object to be heated is subjected to heat treatment, and the temperature of the object to be heated during the heat treatment cycle is detected by the temperature detection means. Then, the determining means determines whether the difference between the temperature detected in the predetermined heat treatment cycle and the corresponding temperature detected in the previous heat treatment cycle is less than or equal to a certain value. Repeating heat treatment cycles results in a constant temperature profile and less variation in thermal history between heat treatment cycles. Therefore, when it is determined that the temperature difference is below a certain value, stable thermal history processing can be performed by using the original object to be heated.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to illustrated embodiments.

FIG. 1 is an explanatory diagram of the principle of the heat treatment method of the present invention. In the figure, a heating target 11 to be subjected to heat treatment is
2 and transported into the heat treatment chamber 13. The object to be heated is placed in the heat treatment chamber 13 after a predetermined heat treatment.
The object to be heated 11 is taken out from inside by the conveying device 12, and the next object to be heated 11 is subjected to heat treatment. The heat treatment chamber 13 is controlled to a predetermined set temperature by a heating control means 14 . The conveyance device 12 carries out heating object 11 by means of conveyance control means 15.
is transported, and the heat treatment cycle is controlled. The temperature of the heating object 11 during the heat treatment cycle is sampled by the temperature detecting means I6, and a temperature profile is detected. Regarding the temperature profile detected by the temperature detecting means 16, the determining means 17 determines whether the difference in the temperature profile between each heat treatment cycle is less than or equal to a predetermined constant value.

In the above heat treatment method, when performing heat treatment, first, a dummy heating object 11 having the same thermal characteristics as the original heating object 11 is used. Then, when the determining means 17 determines whether the difference in temperature profile between each heat treatment cycle is equal to or less than a predetermined constant value, the original object to be heated 11 is used. Thereby, heat treatment is performed in a state where the temperature profile is stable.

FIG. 2 is an explanatory diagram of a specific heat treatment method based on the above principle. In the figure, a silicon wafer 21, which is an object to be heated, is placed on a wafer support 23 provided on a boat loader 22, and is transported into a quartz tube 24, which is a heat treatment chamber. The quartz tube 24 is provided with a heater 25, and the power supplied to the heater 25 is controlled by the power side '4111 device 26. Further, the temperature of the quartz tube 24 is detected by a temperature detection section 27 using a thermocouple or the like, and the temperature is given to a control device (MPtJ: microprocessor unit) 28. The power control device 26 is controlled by a control device 28 to maintain a predetermined set temperature. Transport of the hoard loader 22 is controlled by a boat loader control device 29 based on commands from a control device 28 . Thereby, the heat treatment cycle according to the predetermined heat treatment is controlled. The wafer support stand 23 is provided with a thermocouple or the like, and the temperature during the heat treatment cycle is detected by the temperature detection section 30. The temperature detected by the temperature detection section 3o is taken into the control device 28 and stored in the storage device 31. That is, the storage device 31 stores the temperature profile in each heat treatment cycle. Furthermore, the silicon wafer 21 is transferred for each heat treatment cycle by a wafer transfer device 32 under the control of the control device 28 . The control device 2 determines whether the difference between the temperature detected in the predetermined number of heat treatment cycles stored in the storage device 31 and the corresponding temperature detected in the previous heat treatment cycle is less than or equal to a certain value. At the same time, each section of the power control device 26, temperature detection section 27, 30, boat loader control device 29, and wafer transfer device 32 is controlled.

In the heat treatment method with the above configuration, first, a dummy silicon wafer 21 having the same thermal characteristics as the original silicon wafer 21 is placed on the wafer support stand 23 of the boat loader 22,
It is carried into the quartz tube 24 and heat treatment is started. Then, the temperature of the dummy silicon wafer 21 is detected by the temperature detection section 30, this temperature is taken in by the control device 28, and the sampling temperature during the heat treatment cycle is stored in the storage device 31. This process is repeated for each thermal cycle. and,
The control device 28 compares the temperature of the predetermined heat treatment cycle with the corresponding sampling temperature of the previous heat treatment cycle, determines that the difference is within, for example, 0.2°C, and Within the set temperature (for example, 900.0±0.5 as the temperature at which the maximum temperature is expected to be obtained)
°C), the wafer transfer device 32
Then, an instruction is issued to remove the dummy silicon wafer 21 and transfer it to the original silicon wafer 21 to be heat-treated. Such heat treatment makes the temperature profile constant and reduces changes in thermal history between heat treatment cycles after wafer transfer.

Therefore, stable thermal history processing can be performed.

FIG. 3 is a diagram showing the temperature profile during the I heat treatment cycle according to the above heat treatment method. As shown in the figure, the sampling time during one heat treatment cycle (L1+t2+t:
l+...1. ) with increasing sampling temperature,
Draw a temperature profile that gradually increases to reach the set temperature of 900.0+0.5°C. The Nth temperature profile (shown by the solid line) and the (N-1)th temperature profile (shown by the dotted line) are the first temperature profile (shown by the dotted line).
The temperature difference is smaller than that shown by the dotted chain line), indicating that the thermal history is stable.

In addition, in the present invention, the difference between the temperature profile to be applied and the sampling temperature to be determined can be arbitrarily determined depending on the object of heat treatment, etc., and is not limited to the embodiments.

In addition, to detect the concentration of the heated object, it is not necessary to measure the actual temperature of the heated object, and any physical quantity corresponding to the temperature of the heated object, such as the amount of power of a heater, may be used.

The heat treatment chamber 13 may be any device that heat-treats an object to be heated such as the silicon wafer 11, for example, an oxidation device, a growth device for various films (silicon oxide film, nitride film, phosphorus glass film, etc.), an etching device, a diffusion device, etc. It may be a device or the like.

Further, the dummy heating target may be one having the same temperature characteristics as the original heating target, for example, the same heat capacity.

(Effects of the Invention) As described above, according to the present invention, before performing the original heat treatment, similar heat treatment is performed using a dummy heating object having the same thermal characteristics as the heat treatment object, and the temperature profile is The heat history can be kept the same, as we are processing the original object to be heated after confirming that it is stable.
Stable heat treatment can be performed, and fluctuations in the characteristics of semiconductor devices and the like can be reduced.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the principle of the heat treatment method of the present invention, FIG. 2 is an explanatory diagram of the configuration of the heat treatment method of the embodiment of the present invention, and FIG. 3 is a diagram showing the temperature profile during one heat treatment cycle of the embodiment of the present invention. FIG. 4 is a diagram showing the variation in current amplification factor with respect to the number of heat treatment cycles. In the figure, 11 is an object to be heated, 12 is a transport device, 13 is a heat treatment chamber, 14 is a heating control means, 15 is a transport control means, 16 is a temperature detection means, and 17 is a discrimination means 17.

Claims (1)

[Claims] Heating control means (14) for controlling the temperature of the heat treatment chamber (13); and an object to be heated (11) in the heat treatment chamber (13).
transport control means (15) for controlling the heat treatment cycle of;
Temperature detection means (16) for detecting the temperature of the object to be heated (11) during each heat treatment cycle, and the temperature detected by the temperature detection means (16) in a predetermined heat treatment cycle and the previous heat treatment cycle. Discrimination means (
17), first repeat the heat treatment using a dummy heating object (11) having the same thermal characteristics as the original heating object (11), and then 1. A heat treatment method for a semiconductor device, characterized in that when it is determined that the temperature is below a certain value, the semiconductor device, which is the original object to be heated (11), is heat treated.