JPS6225254B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vapor phase reaction device for a semiconductor substrate.
In particular, it is an object of the present invention to provide a gas phase reactor having an improved structure for performing a gas phase reaction on a semiconductor substrate. For example, in the manufacture of semiconductor devices, there is a process in which a semiconductor substrate is subjected to a reaction in the gas phase to form an oxide film on its surface and to diffuse impurities to form regions. It is called a phase reactor. In the cross-sectional view showing a part of the MOS-type field effect semiconductor device (hereinafter referred to as MOS-FET) shown in Fig. 1, 1 is an N-type silicon substrate with a specific resistance value of 1 to 10 Ωcm, 2 is a source region 3 is a drain Both regions are formed by selectively diffusing and introducing P-type impurities using the SiO ₂ layer 4 formed on one main surface of the substrate as a mask. Further, 12 is a source electrode provided on the exposed surface of the source region 2;
A drain electrode 13 is provided on the exposed surface of the drain region 3, and a gate electrode 15 is formed on the main surface of the substrate between the source region and the drain region with the gate oxide film 5 interposed therebetween. A depletion layer and an inversion layer are formed by the operation, but the interface between the silicon substrate and the SiO ₂ layer in contact with it has a very complicated appearance, and the Si-SiO ₂ interface is a metal (electrode)-oxidation layer. Induction of charge due to the work function difference (φ _MS ) between a substance and a semiconductor, crystal irregularity caused by discontinuity due to a difference in crystal structure between an oxide and a semiconductor, impurities present in the oxidized part during high-temperature oxidation, and O ₂ becomes abnormal due to diffusion into Si. Furthermore, contamination caused by impurities that are inadvertently attached to SiO ₂ and enter during the processing process exists as a surface defect layer and as a charged body in SiO ₂ , which has a large effect on the electronic state of the Si surface, and ultimately reduces the stability of the FET. It causes problems with sexuality.
Based on the above reasons, careful handling is required during the manufacturing process, and the above MOS-FET,
Furthermore, in general, a high purity quartz tube is used as a reaction vessel due to concerns such as undesired impurity contamination and heat resistance during vapor phase growth such as oxide layer formation and impurity diffusion in the manufacture of MOS-ICs. As shown in FIG. 2, there is a gas introduction section for forming a reaction atmosphere at one end of the quartz tube 6 (excluding a part of the gas introduction tube 7, the gas source, gas amount adjustment device, etc. are not described). A semiconductor substrate support jig 18 having a semiconductor substrate 8 (not shown) with the other end open and supporting a semiconductor substrate 8 from the lever is inserted. This loading is carried out using a semiconductor substrate support jig moving rod 9 (hereinafter abbreviated as moving rod) as shown in FIG. The moving rod has a "key portion" 9a formed at its tip so that it can also be used to take out the semiconductor substrate support jig. The semiconductor substrate is heated by a high-frequency coil surrounded by a quartz tube, heated by a soaking tube, and subjected to a gas phase reaction in a predetermined atmosphere. When the reaction is completed and the temperature is lowered, the moving rod is inserted and operated (taken out) as shown in FIG. 3, and outside air (air) flows into the container by convection. The above causes Qss to warp on the semiconductor substrate.
(Surface State) increases. The above-mentioned warping has the disadvantage that, for example, the precision of the pattern is reduced due to poor press-fitting of the mask during photolithography, and fine patterning is impaired. Furthermore, an increase in Qss has a serious drawback in that it deteriorates the layer quality of an example of a SiO ₂ layer formed on a semiconductor substrate. (The above
Qss represents the effective total charge present in the interfacial system,
It is expressed by the following formula: Qss=Vss×Cox. In the above equation, Cox is the charge capacity of the oxide film, and Vss≡Vth−V ₁ th, where Vth is the “threshold voltage” and V ₁ th is the “intrinsic threshold voltage.” do. ) The present invention provides an improved semiconductor substrate vapor phase reactor for eliminating the drawbacks of the conventional vapor phase reactors described above. A vapor phase reaction apparatus for semiconductor substrates according to the present invention includes a heat-resistant vapor phase reaction vessel having a gas outlet at one end and closed at the other end with a lid, a heating means surrounding the reaction vessel, and a heating means for surrounding the reaction vessel. In a semiconductor substrate phase inversion device comprising a reaction gas introduction part for introducing a reaction gas for performing a gas phase reaction on a semiconductor substrate placed on a semiconductor substrate support jig in a container, the lid has a flat part; It has a side part extending from the flat part at the periphery of the flat part, and at least a part of the side part loosely fits into the open end of the reaction vessel, closes it, and connects to the flat part. It is characterized by having an opening through which the provided semiconductor substrate support jig passes, and a cutout extending from the opening to the side surface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the drawings regarding an embodiment of a vapor phase reaction apparatus for a semiconductor substrate. In FIG. 4, which is a side cross-sectional view, 6 is a quartz tube of the reaction vessel, and at one end there is a gas introduction part 7 for forming a reaction atmosphere (except for a part of the gas introduction tube, there is no gas source, A semiconductor substrate support jig 18 is installed in which the semiconductor substrate 8 is supported by a lever with the other end open. This charging is carried out using a moving rod 9 as shown in FIGS. 6 and 7. Note that the moving rod has a "key portion" formed at its tip so that it can also be used to take out the semiconductor substrate support jig.
The semiconductor substrate is heated by a high-frequency coil surrounded by a quartz tube, heated by a soaking tube, and subjected to a gas phase reaction in a predetermined atmosphere. When the reaction is completed, the lid 10 as shown in FIGS. 4 and 5
is attached to the open end of the quartz tube 6. The lid body is made of quartz, which is the same material as the quartz tube 6, and is shown in FIG.
Figure b is a side view viewed from the axial direction, Figure b is a side cross-sectional view,
As shown in the bottom view in FIG. It fits loosely into the side surface of the quartz tube 6 at the part and becomes detachable. Further, the opening 10c' is extended to the side surface portion 10b to form a cutout portion 10c. According to the present invention, since convection of outside air is prevented from flowing into the reaction vessel, the warpage of the semiconductor substrate and the Qss
This has the significant advantage of preventing the increase in That is, the warpage causes a decrease in pattern accuracy due to poor press contact of the mask during photolithography, as an example, and fine patterning is impaired. Also, the increase in Qss is MOS−
Damages the electrical characteristics of FETs and MOS-ICs. The present invention has reduced the variation in Vth value in an example of a MOS IC from the conventional ±0.36v to ±0.12v. Next, according to the shape of the lid according to the present invention, when it is fitted onto the end of the quartz tube of the gas phase reaction vessel as shown in FIG. 6, the moving rod 9 can be easily inserted. Also the 7th
As shown in the figure, since the angle (θ) for moving the rod up and down can be widely tolerated, the rod will not break even if the installation height of the reaction container is considerably different from the height of the operator of the moving rod. It has advantages such as easy operation.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a part of a MOS-FET, Figure 2 is a cross-sectional view of a part of a semiconductor substrate vapor phase reaction device, and Figure 3 is a cross-sectional view for explaining the operation of the device shown in Figure 2. , FIG. 4 is a side cross-sectional view for explaining a gas phase reactor according to an embodiment of the present invention, and FIG. 5 is a side view showing a part of the lid in FIG. 4. FIG. , Figure b is a side sectional view, Figure c is a bottom view, and Figures 6 and 7 are perspective views for explaining the present invention. Note that the same reference numerals in the drawings indicate the same or corresponding parts, respectively. 6... Quartz tube (reaction vessel), 8... Semiconductor substrate, 9... Rod for moving semiconductor substrate support jig, 10
... Lid body, 10a ... Plane part, 10b ... Side part, 10c ... Cutout part.

Claims (1)

[Claims] 1. A heat-resistant gas phase reaction vessel having a gas outlet at one end and closed with a lid at the other end, a heating means surrounding the reaction vessel, and a semiconductor substrate support jig placed within the reaction vessel. In a semiconductor substrate reactor equipped with a reaction gas introduction part for introducing a reaction gas for performing a gas phase reaction on a semiconductor substrate, the lid has a flat part and a lid extending from the flat part at the periphery of the flat part. At least a part of the side surface part loosely fits into and closes the open end of the reaction vessel, and has an opening provided in the flat part through which a semiconductor substrate support jig is passed. 1. A gas phase reaction device for a semiconductor substrate, characterized in that the semiconductor substrate has a cutout portion extending to a side surface.