JPS5942969B2 - Semiconductor heat treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a semiconductor heat treatment apparatus for heat treating semiconductor wafers and the like.

Recently, the size of semiconductor wafers has gradually increased to 5 inches in diameter, and the semiconductor processing tubes required for that purpose are 150 to 16 inches.
It is large with an outer diameter of 0mmψ.

The processing boats on which the wafers are placed have also grown to 800 mm in length.

Current semiconductor heat treatment tubes sometimes use a baffle plate to prevent the inflow of external gas, to effectively use the processing gas, or to equalize the internal gas, but they are not sealed on the output side of the processing gas. Attach the cap for
Preventing gas from flowing out from inside the processing tube and preventing external gas from flowing in is carried out.

Furthermore, when heat-treating wafers, the boat carrying the wafers is inserted into the high-temperature processing section through a part with a steep temperature gradient, or pulled out from the high-temperature processing section.
In order to prevent problems such as cracks due to thermal stress and short circuits due to pinholes, as well as thermal damage to the end of the processing tube that is in contact with the outside air, the processing tube should be extended from the end of the insulator toward the processing gas output side. An overhang portion is provided to make the temperature gradient gentler and to enable preheating or heat removal of the wafer.

However, when the processing tube is extended in this manner, the length of the longitudinal portion of the processing tube where the temperature is constant, that is, the soaking length, is drastically reduced, resulting in a problem of lowering the semiconductor processing capacity.

As described below, it is impossible to correct the above problem by changing the amount of heat generated at the end of the heating section.

Generally, inside the processing tube at both ends of the heating section, heat naturally dissipates to the outside, so the temperature inevitably decreases compared to the center of the heating section. is increased to flatten the internal temperature.

On the overhanging processing gas output side, this heat dissipation becomes even greater, so the amount of heat generated must be higher than that on the processing gas input side. However, even with this method, when the temperature is set to be uniform at 1000°C, for example, there will be a locally low temperature area (
Dip) appears. Therefore, the soaking length is narrowed to one length excluding the local low-temperature portion (Dip), and becomes shorter.

An object of the present invention is to solve the above-mentioned problems by substantially eliminating localized low-temperature areas without increasing the number of heating elements used in the longitudinal direction or increasing the amount of electric power. The first objective is to increase the amount of semiconductor heat treatment by increasing the soaking length that allows semiconductor heat treatment.

The present invention will be described with reference to the embodiments shown in the accompanying drawings.The structure is such that the outer surface of the heating section 3 of the processing tube 2 is made up of a heating section 3, an overhang section 4, and a sealing section 5 in order from the processing gas input side. In the processing tube 2, which is provided with heating elements 6 distributed in the longitudinal direction of the processing tube 2 and provided with a heat insulator 7 that covers the heating elements 6, the heating elements of the heating section are arranged so that the heating elements are arranged in a unit length in the longitudinal direction of the processing tube. The heating unit 3 is configured so that the amount of heat generated per hit is large on the output side of the processing gas, second on the input side, and lowest at the center, and the above-mentioned heating unit 3 extends from the vicinity of the gas output side end 3d of the heating unit 3 to the vicinity of the sealing unit 5. This is a semiconductor heat processing apparatus in which a plurality of convection prevention plates 1 are provided inside a processing tube in a direction that blocks the flow of processing gas, and spaces are provided between the convection prevention plates 1.

8 is a wafer and 9 is a boat.

3a, 3b, and 3c are the names of parts of the heating section 3 divided into three parts.

3d is the gas output side end of the heating section 3.

Further, 6a, 6b, 6c are 3a of the heating part 3 of the heating element 6.
, 3b, 3c. The present invention is as described above, and the cap and the convection prevention plate are taken out of the heated processing tube, and the boat carrying the wafer is inserted and set at a predetermined soaking position of the processing tube, and then , install the convection prevention plate and cap.

During this time, the internal temperature of the processing tube at the boat position can be adjusted to a predetermined value by flowing the processing gas from the gas input or not. It is also possible to heat-process the semiconductor by inserting the boat into a predetermined upper part of the processing tube at room temperature, setting the convection prevention plate and cap, and supplying the processing gas at a predetermined programmed temperature-time cycle.

Next, embodiments of the present invention will be described.

The outer surface temperatures of the three portions 6a, 6b, and 6c of the heating section 3 are Ta, Tb, and Tc in FIG. 2, and the respective power ratios are Wa, Wb, and Wc, and a quartz tube with an outer diameter of 160ψ is used as the processing tube. Five convection prevention plates 1a, 1 of 120ψ are used.
b, 1c, 1d, 1e almost 300m77! When placed between the ranges, a soaking length of approximately 600 mm with a fluctuation range of ±0.1° C. was obtained as shown in FIG.

The temperature and power consumption ratio are shown in Table 1. In addition, when three convection prevention plates 1a, 1b, and 1c are provided in the vicinity of the end 3d of the heating section 3 in a range of 100 mT1L, as shown in Table 2 and Fig. 4, a localized low temperature area of approximately 10°C is generated. Fluctuation range ±1℃, soaking length 400m7! It becomes L.

In addition, in the case of the conventional example without a convection prevention plate, as shown in Table 3 and FIG. 5, a localized low temperature area of approximately 50°C occurs, and the soaking length with a fluctuation range of ±1°C is reduced to 350 mTL.

The convection development in the above-mentioned conventional example will be explained with reference to FIG. 6. Arrow A is shown inside the processing tube. , Al appears, and the processing gas heated in the heating section 3 is cooled in the sealing section of the overhang section 4, as indicated by the arrow A. It returns through the lower side of the processing tube 2, reaches the middle of the heating section 3, and returns through the upper part of the processing tube, repeating the course. In addition, a small convection as indicated by arrow A2, which returns the temperature in a short range, also occurs.

Further, as shown in FIG. 7, the temperature T at the upper part of the processing tube 2 is a curve A, which shows a flat characteristic at the longitudinal center of the processing tube, but curves B and B at the center of the processing tube 2 are flat. In the curve C of the lower part C, there is a local low-temperature area B due to the above-mentioned cooling convection in the longitudinal direction of the processing tube.

, CO appears. As shown by curve D, the temperature at position D outside the processing tube is large on the processing gas output side, is the same on the input side, and is lowest at the center. The present invention provides the following features: ``From the vicinity of the processing gas output side end of the heating section of the processing tube to the vicinity of the sealing section,
A plurality of convection prevention plates are provided in a direction that blocks the internal convection of the processing gas, and a space is provided between the convection prevention plates so that the heating element of the heating section has a heat generation amount per unit length of the processing tube in the longitudinal direction of the processing gas. The overhang is large on the output side, the input side is the same, and the center is the lowest.The temperature characteristics in the longitudinal direction of the processing tube at the center of the processing tube can be adjusted without adding a heating element or increasing power. The soaking length can be increased by substantially eliminating localized low-temperature areas, and the amount of heat treatment of the semiconductor can be increased.

[Brief Description of the Drawings] Fig. 1 is a sectional view of an embodiment of the present invention, Fig. 2 is a schematic diagram of a portion corresponding to Fig. 1, Fig. 3 is a characteristic diagram of an embodiment of the present invention, and Fig. 4 is a sectional view of an embodiment of the present invention. Figure 5 is a characteristic diagram of another embodiment of the present invention, Figure 5 is a characteristic diagram of a conventional example, Figure 6 is a schematic diagram showing convection in the processing tube of the conventional example, and Figure 7 is a diagram showing the positions in the same treatment tube. It is a schematic diagram of temperature distribution. 1... Convection prevention plate, 2... Processing pipe, 3
・・・・・・Heating part, 4... Overhang part, 5゛゜゜゜゛゛゜゜゜゛ Sealing part, 6... Heat generating element, 7...
...Insulator, 3d...Gas output side end.

Claims (1)

[Claims] 1. Heat generating elements 6 distributed in the longitudinal direction of the processing tube 2 are provided on the outer surface of the upper heating section 3 of the processing tube 2 consisting of the heating section 3, the overhang section 4, and the sealing section 5, sequentially from the processing gas input side,
A cap-type processing tube 2 provided with a heat insulator 7 that covers the heating element 6
, the heating element 6 of the heating section 3 has a large calorific value per unit length in the longitudinal direction of the processing tube 2 on the processing gas output side;
The input side is configured to be lowest at the center, and a plurality of convection prevention plates 1 are provided inside the processing tube 2 from the vicinity of the gas output side end 3d of the heating section 3 to the vicinity of the sealing section 5. A semiconductor heat processing apparatus characterized in that the convection prevention plates 1 are provided in a direction to block the flow of processing gas, and a space is provided between the convection prevention plates 1.