JPH03185831A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form a nondefective layer also under the interface between a substrate and an epitaxial layer, by holding a semiconductor silicon substrate in a first specified temperature range, increasing the temperature at a specified rate, from the first temperature range to a second specified temperature range, and holding the substrate for a period shorter than or equal to a specified interval. CONSTITUTION:A semiconductor silicon substrate 1 is held for 8 hours or less in a first temperature range from 450 deg.C to 600 deg.C. The temperature is increased from the first temperature range to the second temperature range from 750 deg.C to 900 deg.C, at a rate of 5 deg.C/min. The substrate is held for 4 hours or less in the second temperature range. An epitaxial layer 2 is formed on the surface of the semiconductor silicon substrate 1 after the holding in the second temperature range is finished. That is, by setting the second temperature range to be from 750 deg.C to 900 deg.C, the size of a defect is restricted within a radius capable of dissolution and outward diffusion in the temperature range of a subsequent epitaxial process. Hence the dissolution and outward diffusion of defects are progressed. Thereby a nondefective layer 4 of about 10mum in thickness is formed under the interface between the substrate surface and the epitaxial layer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of manufacturing a semiconductor device, in particular a method in which epitaxial growth is performed on the surface of a semiconductor silicon substrate. The present invention relates to a method for manufacturing semiconductor devices using intrinsic getter (hereinafter referred to as IG) technology.

[Prior Art] Conventionally, as a technology applied to a semiconductor silicon substrate on which epitaxial growth is performed, for example, as disclosed in Japanese Patent Publication No. 62-16537, oxygen precipitated nuclei (hereinafter referred to as defects) that act as getter sites have been disclosed. ) is formed on the surface layer of the substrate close to the device fabrication area to enhance the effect of trapping impurities. The important point in this conventional technology is that the defects basically reach the surface of the substrate body before epitaxial growth, and this heat treatment method eliminates the borizing process that was previously required before epitaxial growth. I'm trying to make it possible to omit it.

[Problems to be Solved by the Invention] However, according to the prior art, the
After the heat treatment process at 0° C., many defects with advanced growth occur in the substrate. Since the size of these defects is larger than the critical radius that can be dissolved in the temperature range (1100 to 1200° C.) of the next epitaxial growth step, they remain as they are and propagate to the epitaxial layer.

A so-called defect penetration phenomenon occurs. This ultimately results in the production of defective products.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned drawbacks of the prior art, and includes a method for manufacturing a semiconductor device, in which a semiconductor silicon substrate is heated in a first temperature range of 450°C to 600°C. A step of holding for 8 hours or less and a temperature range of 750°C to 9°C from the first temperature range.
A step of increasing the temperature to a second temperature range of 00°C at a rate of 5°C/min or less and holding it in this second temperature range for 4 hours or less, and after the holding in the second temperature range is completed, the semiconductor It is characterized by comprising a step of forming an epitaxial layer on the surface of a silicon substrate.

[Function] By setting the second temperature range to 750°C to 900°C, the present invention can reduce the size of defects that can be dissolved and outwardly diffused in the temperature range of the next epitaxial process. Stay within the radius. Therefore, in the epitaxial process, defects are dissolved into solution and diffused out. As a result, an additional 10μI was added to the substrate surface below the interface with the epitaxial layer.
A defect-free layer with a certain degree is formed.

As mentioned above, if the second temperature range is 100
If the temperature is 0° C. to 1300° C., defects occurring in the semiconductor substrate will grow beyond the critical radius and will not be dissolved again in the atmosphere of the subsequent epitaxial process. There is a high risk that the remaining defects will propagate during epitaxial growth.

On the other hand, in the second temperature range of 750°C to 900°C adopted in the present invention, although defects occur throughout the substrate, they do not grow sufficiently, and therefore, solutionization occurs in the atmosphere for the next epitaxial growth. Or, those near the surface may diffuse out of the substrate.

In this manner, the present invention utilizes the atmosphere of the epitaxial growth process to form a defect-free layer on the surface of the substrate body at the same time as the epitaxial layer.

Note that the first temperature range (450° C. to 600° C.) is important as a temperature for creating oxygen precipitation nuclei that become the core of defects. Holding in this temperature range for 8 hours or less is necessary to ensure the defect density, and since this density almost reaches equilibrium in 8 hours, there is no need to hold it any longer. The second temperature range of 750° C. to 900° C. is a temperature range adopted to prevent the created defects from growing beyond the critical radius. Raising the temperature to this temperature range at a rate of 5°C/min or less is 5450°C if the temperature is rapidly raised at a rate exceeding 5°C/min.
There is a possibility that defects created during heat treatment at ~600°C cannot grow and disappear. Furthermore, in the second temperature range, the retention time is limited to 4 hours or less because of the defects created.
This is necessary in order to grow the epitaxial layer to such an extent that in the temperature atmosphere of the next epitaxial step, the material near the interface of the epitaxial layer disappears, but the material inside the substrate does not disappear.

[Example 1] Oxygen concentration 14.0×10”atoms/cc [Old
A mirror-finished silicon wafer (according to ASTM standard) was held at the first temperature range (600°C) for 4 hours, and then heated at a rate of 0.5°C/min to the second temperature range (SOO°C). After heating, the wafer was held for 2 hours.Furthermore, a silicon epitaxial layer was grown to a thickness of 5 μm by a conventional method on the mirror-finished wafer heat-treated under the above conditions.

The silicon wafer that has been processed in this way is heated to 1000℃.
After heat treatment for 16 hours, defects were observed between the bones.

FIG. 1 is an enlarged view of this interosseous surface. As is clear from FIG. 1, in this example, there is a defect-free layer of about 10 to 100% below the epitaxial layer and also on the surface layer of the silicon substrate body.
The crystal defects of 30 μm are formed in a well-controlled manner, and there are enough crystal defects inside the substrate to exhibit the getter effect.

[Example 2] Oxygen concentration 14.0×10”atoms/cc [01d
After holding an etched silicon wafer (according to ASTM standard) in a first temperature range (600°C) for 4 hours, the temperature was raised to a second temperature range (800°C) at a rate of 0.5°C,
After raising the temperature, it was held for 2 hours. Furthermore, the etched wafer heat-treated under the above conditions was subjected to 15 μm M surface polishing, and then 5 μm
A silicon epitaxial layer was grown to a thickness of m by a conventional method.

The silicon wafer that has been processed in this way is heated to 1000℃.
The film was heat-treated for 16 hours, and then folded and observed for defects.

The results were similar to Example 1.

In addition to the above two embodiments, the first temperature range, the second temperature range, the holding time, and the rate of temperature increase from the first temperature range to the second temperature range are each set according to the structure of the present invention. The same process was carried out with various changes according to the above, and almost the same results as in the above two examples were obtained.

[Reference Example 1] Oxygen concentration 14.0×10”atoms/cc [Old
According to the ASTM standard], a mirror-finished silicon wafer was held in the first temperature range (600°C) for 4 hours, and then heated to 1000°C.
The temperature was raised to 0.5°C/min and held for 2 hours after the temperature was raised. Further, a silicon epitaxial layer with a thickness of 5 μm was grown by a conventional method on the mirror-finished wafer heat-treated under the above conditions.

The silicon wafer that has been processed in this way is heated to 1000℃.
The film was heat-treated for 16 hours, and then folded and observed for defects.

FIG. 2 is an enlarged view of this interosseous surface. As is clear from FIG. 2, in this reference example, almost no defect-free layer was formed on the surface layer of the substrate body below the epitaxial layer, and many defects penetrated into the epitaxial layer.

In other words, when the temperature corresponding to the second temperature range is 1000°C as in this reference example, the growth of crystal defects progresses, the size becomes huge, and the interface with the epitaxial layer occurs during the epitaxial process. It can be seen that defects remain underneath, and that defects eventually penetrate into the epitaxial layer, which should be defect-free.

[Reference Example 2] Oxygen concentration 18.0×10”atoms/cc [Old
An etched silicon wafer (according to ASTM standard) was kept in the first temperature range (600°C) for 4 hours, and then
The temperature was raised to 00°C at a rate of 0.5°C and held for 2 hours after the temperature was raised. Further, the etched wafer heat-treated under the above conditions was polished to a depth of 15 .mu.m, and a silicon epitaxial layer was grown thereon to a thickness of 5 .mu.m by a conventional method.

The silicon wafer that has been processed in this way is heated to 1000℃.
The film was heat-treated for 16 hours, and then folded and observed for defects.

The results were similar to those in Reference Example 1.

In addition to the above two reference examples, the first temperature range, the holding time, and the rate of temperature increase from the first temperature range to the second temperature range were variously changed according to the configuration of the present invention. The temperature in the second temperature range is too.

A similar process was carried out at a temperature higher than 0.degree. C., but almost the same results as in the above two reference examples were obtained.

[Effects of the Invention] According to the manufacturing method of the present invention, since the second temperature range is set at 750°C to 900°C, the size of defects is controlled and solution treatment is performed in an atmosphere at a temperature similar to that of the next epitaxial layer. Alternatively, by outward diffusion, a defect-free layer can also be formed under the interface with the epitaxial layer. Therefore, defects do not penetrate through the epitaxial layer. As a result of improved product yield, productivity also increases.

[Brief explanation of drawings]

FIG. 1 is an enlarged view of an interosseous cross section of a silicon substrate manufactured using the manufacturing method according to the present invention. FIG. 2 is an enlarged view of an interosseous cross section of a silicon substrate manufactured using a conventional manufacturing method. 1...Silicon substrate 2...Epitaxial layer 3...Defect 4...Defect-free layer Procedure amendment (method) % formula % Display of incident 1999 Patent Application No. 323789 2゜Title of invention: Method of manufacturing semiconductor devices 3゜Relationship with the amended case

Claims (1)

[Claims] 1. A step of holding the semiconductor silicon substrate in a first temperature range of 450°C to 600°C for 8 hours or less, and a step of holding the semiconductor silicon substrate at a rate of 5°C/min or less from the first temperature range to a second temperature range of 750°C to 900°C. A semiconductor comprising the steps of raising the temperature at a rapid rate and holding it in this second temperature range for 4 hours or less, and forming an epitaxial layer on the surface of the semiconductor silicon substrate after the holding in the second temperature range is completed. Method of manufacturing the device.