JP2000252222A - Semiconductor manufacturing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cause no fatigue destruction of a guide plate due to long service time and prevent the contamination inside a furnace due to damages as well as the contamination of semiconductor wafers. SOLUTION: This equipment is provided with a wafer loading table arranged within a reaction furnace, a reaction gas supply mechanism to supply a reaction gas to the wafer loading table, a guide plate 2 to lead the reaction gas supplied from the reaction gas supply mechanism to the wafer loading table and guide a reamining gas after reaction to an exhaust mechanism side from the wafer loading table, and a supporting plate 3 to support the guide plate 2. The guide plate 2 is divided into a plurality of members and communicated to each other, and developed and arranged in a way that their surfaces may surround the wafer loading table.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a single-wafer CVD furnace, an epitaxial growth furnace, and the like for manufacturing semiconductor devices, for example, to extend the life of components, and to deteriorate or damage members during operation. The present invention relates to a device structure for preventing occurrence of furnace contamination accompanying the above.

[0002]

2. Description of the Related Art A reactive gas is introduced onto a semiconductor wafer placed on a susceptor heated to a high temperature by means of high frequency heating, resistance heating, lamp heating, etc. to cause a gas phase decomposition reaction or the like, thereby causing a wafer surface. Semiconductor manufacturing apparatuses such as CVD furnaces and epitaxial growth furnaces on which various thin films meeting the requirements of devices are formed have been known. Since the film thickness formed by the gas phase reaction directly affects the yield and performance of the final device, uniformization of the reaction temperature within the wafer surface is a very important control factor.In recent years, to address this problem, Due to the increase in the diameter of wafers, single-wafer reaction furnaces for processing wafers one by one have come to be used. The single-wafer type has, for example, a structure as shown in FIGS.
The wafer placed on the wafer mounting table, which is called a wafer mounting table, reaches a high temperature by, for example, heating with an infrared lamp. When a reaction gas is introduced into the wafer, a desired thin film grows on the wafer by thermal decomposition. The growth method is basically not different from a barrel-type reactor or a pancake-type reactor in which a plurality of substrates used for a long time are loaded. However, for example, when the wafer is silicon, a barrel-type reactor or a pancake-type reactor raises the temperature of a large susceptor capable of loading a large number of sheets from a room temperature to a reaction temperature of about 1100 ° C. 800 ° C for reactor
The wafer is loaded on a susceptor held nearby, and then the temperature is rapidly raised to the reaction temperature. From the necessity of increasing the production efficiency, it is desirable that the rate of temperature increase is higher. For this reason, instead of using a detour heating method such as raising the temperature of the wafer via a susceptor, for example, when the wafer is silicon, the above-described infrared lamp which directly irradiates the wafer with good absorption infrared rays and raises the temperature is used. Heating is used. In addition, in order to uniformly heat the wafer itself and speed up the temperature rise and fall, it is ideal that there are no parts having a large heat capacity or an asymmetric structure other than the wafer in the furnace.
However, the quality of the thin film formed on the wafer surface,
In order to precisely control the formation rate, it is necessary to precisely and automatically control the temperature of the wafer during the process by adjusting the lamp output. For this reason, it is necessary to arrange a thermocouple around the wafer to measure the temperature of the wafer. This causes the symmetry of the temperature distribution in the furnace and disrupts the flow of the reactant gas around the wafer. Conventionally, in order to solve the above problem, a susceptor 1 'and a guide plate 2' around the susceptor for suppressing the turbulent flow of the reaction gas on the wafer surface and a support plate 3 'for supporting the guide plate 2' An air gap was provided therebetween, and the thermocouple 4 ′ was housed therein. This eliminates the disturbance of the flow of the reaction gas, while the temperature measured by the thermocouple is the temperature of this gap, so that the combined thermal characteristics of the guide plate 2 'and the support plate 3' Need to be as close as possible to the combined thermal properties of the wafer and susceptor. In particular, when there is a difference in heat capacity, a large difference occurs between the temperature measured by the thermocouple and the actual temperature of the wafer when the temperature is increased or decreased. That is, when the combined heat capacity of the wafer and the susceptor is smaller than the combined heat capacity of the guide plate and the support plate, if the temperature of the wafer is to be automatically controlled as described above, a temperature increase rate and a temperature decrease rate larger than the set values are set. Give it. At this time, thermal stress generated in the wafer due to rapid temperature fluctuation of the wafer causes a slip in the wafer. Slip is a serious quality defect and must be avoided as much as possible. For this reason, make the guide plate and support plate lightweight and thin,
This heat capacity was reduced as much as possible.

[0003]

However, as described above, the mechanism is a rapid heating system, and if the temperature is repeatedly increased and decreased, adverse effects due to the reduction in weight and thickness arise. Although the guide plate 2 'is supported by the support plate 3' underneath, the guide plate 2 'is not integrated, so that a particularly narrow portion of the guide plate 2' may be fatigue-ruptured by repeated stress of temperature increase and decrease. As shown in FIG. 6, when the temperature rises, the guide plate 2 'blocks the radiation from the lamp from the support plate 3' side by the support plate, and dissipates the heat to the support plate 3 'side as shown in FIG. Is also blocked by the support plate, and repeats a warping motion when the temperature is raised and when the temperature is lowered. In particular, in the case of a rectangular guide plate, the narrow portion in the long-axis direction is narrower than the narrow portion in the short-axis direction, so that stress is concentrated here.

[0004] This is the same regardless of the shape of the support plate. When the guide plate and the support plate are arranged vertically and shield each other from radiation from the lamp, it is inevitable that heating from the guide plate side and heating from the support plate side become asymmetric. is there. Even if the support plate can be removed, since a temperature detector near the wafer mounting table and a jig for supporting the wafer mounting table are essential, these structures cause thermal asymmetry. In any case, if used without noticing the destruction caused by repeated warping, even if the surface layer is surface-treated to prevent contamination, the inside is, for example, a carbon material as it is. Damage to the wafers caused by this.

According to the present invention, in a semiconductor manufacturing apparatus, in particular, in a reactor for forming a thin film on the surface of a semiconductor wafer, fatigue failure of a guide plate caused by such repetitive heating and cooling is prevented to extend the life of the guide plate and improve the life of the guide plate. The purpose of the present invention is to prevent contamination in the furnace caused by the above, and consequently contamination to a semiconductor wafer as a final product.

[0006]

According to a first aspect of the present invention, there is provided a semiconductor manufacturing apparatus, in particular, a reactor for forming a thin film on a semiconductor wafer surface, wherein a wafer mounting table disposed in the reactor and a wafer mounting table. A reaction gas supply mechanism that supplies a reaction gas onto the mounting table, and a guide plate that guides the reaction gas supplied from the reaction gas supply mechanism to the wafer mounting table and guides the remaining gas after the reaction from the wafer mounting table to the exhaust mechanism side. And a support plate for supporting the guide plate,
And the guide plate is divided into a plurality of members, which are connected to each other, and the surfaces of which are arranged so as to surround the wafer mounting table.

The second invention is characterized in that the connecting portions of the plurality of members are configured to overlap each other.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings for understanding the present invention. FIG. 1 is a plan view showing a first embodiment of the present invention, and FIG. 2 is a front view showing the same. The semiconductor manufacturing apparatus according to the present embodiment
A disc-shaped susceptor 1 serving as a wafer mounting table arranged in a reactor, a guide plate 2 surrounding the susceptor and deployed so that its surface is substantially flush with the susceptor surface, and for supporting the guide plate And the guide plate is divided into two members at the narrow portion **.
Of course, the divided portion of each member is subjected to a surface treatment as in the related art, so that impurities from inside the member do not leak out.
The support plate 3 below the guide plate supports the individual members of the divided guide plate so that the individual members are connected at the divided portion. In addition, a thermocouple 4 for temperature detection is provided on the lower inner peripheral portion of the guide plate and near the susceptor.
A groove is provided so that the can be loaded. The guide plate 2 introduces the reaction gas from the reaction gas supply mechanism to the surface of the wafer mounted on the susceptor 1 to be processed without generating turbulence, and guides the gas after the reaction to the exhaust mechanism side. And protects the thermocouple 4. Since it is necessary to guide the reaction gas from introduction to exhaust, the shape is a rectangle whose major axis is from the supply mechanism side to the exhaust mechanism side. Reference numeral 5 in FIG. 2 denotes a quartz holder that further supports the support plate 3 from below.

Normally, the effect of repetitive warpage caused by repetition of temperature rise and fall is most remarkable in a narrow portion. However, because of the above-described structure, expansion and contraction eventually causes a change in a gap in a divided portion. Instead, it does not lead to cracks.

FIG. 3 is a front view showing a second embodiment of the present invention. The feature of this embodiment is that the shape of the divided portion of the guide plate in the first embodiment is such that one member (the right member in FIG. 3) overlaps the upper surface of the other member (the left member in FIG. 3). That is, it has a stepped step that wraps. According to this configuration, since the divided portion itself is less likely to be directly exposed to the atmosphere in the furnace of the apparatus, for example, a temperature measurement error due to a thermocouple on the support plate side is less likely to occur. There are advantages such as difficulty in depositing living things.

[0011]

EXAMPLE A semiconductor silicon wafer was heat-treated using the semiconductor manufacturing apparatus of the present invention disclosed in the section of the embodiment of the present invention. The guide plate 2, the susceptor 1, and the support plate 3 are made of carbon, but their surfaces are heat-resistant,
It is coated with SiC to prevent contamination. For comparison with the related art, a semiconductor manufacturing apparatus having the configuration shown in FIG. 6 was used as a control. Diameter φ of silicon wafer to be processed
200mm, support plate outer diameter φ254mm, guide plate outer size 251.2 × 282.9mm, one cycle of heat treatment is 950-1200
8 minutes at ° C. The results are shown in the graph of FIG. The degree of contamination in the heat-treated silicon wafer was evaluated based on the Fe-B concentration (atom / cc). The horizontal axis in FIG. 4 is the number of heat treatments.

As is clear from the graph of FIG. 4, in the conventional case, the concentration of Fe-B has already been increased from the number of heat treatments of 200 times or less, and the contamination state progresses. In the case of the present invention, no contamination occurs up to less than 4000 times.

[0013]

As described above, in the semiconductor manufacturing apparatus according to the first aspect of the present invention, the wafer mounting table disposed in the reactor and the reaction gas supply mechanism for supplying the reaction gas to the wafer mounting table are provided. A guide plate that guides the reaction gas supplied from the reaction gas supply mechanism to the wafer mounting table, and guides the remaining gas after the reaction from the wafer mounting table to the exhaust mechanism side,
And a support plate for supporting the guide plate, and the guide plate is divided into a plurality of members, which are connected and developed around the wafer mounting table. In addition, cracks are not generated due to expansion and contraction due to repetition of temperature reduction, and impurity contamination from the crack location does not reach the apparatus or contaminate the processed wafer. Naturally, the life of the guide plate is prolonged, and the occurrence of contamination is drastically reduced, so that the life of other components in the furnace of the apparatus is also prolonged. Further, in the second invention, since the divided portions of the guide plate are overlapped by the respective members in the first invention, there is no possibility that reaction by-products are deposited in the gaps between the divided portions, and the cleaning is performed. Sex is maintained.

[Brief description of the drawings]

FIG. 1 is a plan view of a first embodiment of the present invention.

FIG. 2 is a front view of the first embodiment of the present invention.

FIG. 3 is a front view of a second embodiment of the present invention.

FIG. 4 is a graph showing test results in the example of the present invention.

FIG. 5 is a plan view of a conventional semiconductor manufacturing apparatus.

FIG. 6 is a front view of a conventional semiconductor manufacturing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Susceptor 2 Guide plate 3 Support plate 4 Thermocouple 5 Quartz holder

Claims (2)

[Claims] 1. A wafer mounting table disposed in a reaction furnace, a reaction gas supply mechanism for supplying a reaction gas onto the wafer mounting table, and a reaction gas supplied from the reaction gas supply mechanism guided to the wafer mounting table. A guide plate for guiding the residual gas after the reaction from the wafer mounting table to the exhaust mechanism side, and a support plate for supporting the guide plate, wherein the guide plate is formed by connecting a plurality of divided members. A semiconductor manufacturing apparatus, wherein the semiconductor manufacturing apparatus is configured and arranged so that its surface surrounds and surrounds a wafer mounting table. 2. The semiconductor manufacturing apparatus according to claim 1, wherein said plurality of members have a structure in which mutually connected portions overlap each other.