JP2003142357A - Method for manufacturing semiconductor device, method for measuring thickness of epitaxial film and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the measurement of the thickness of an epitaxial film, even on the way of a manufacturing step. SOLUTION: The method for manufacturing the semiconductor device comprises the steps of forming a recess 5 or a protrusion on the upper surface of a semiconductor substrate 1, then performing a homoepitaxy on the upper surface of the substrate 1 to form a homoepitaxial film 4 and a defect layer 6, and measuring the thickness of the film 4 based on the measurement of the length dimension of the layer 6 in the off direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device having a homoepitaxial film formed on the upper surface of a semiconductor substrate having an off angle, a method for measuring the film thickness of the homoepitaxial film, and the semiconductor device.

[0002]

2. Description of the Related Art When manufacturing a general Si semiconductor device, SIMS is a conventional technique for evaluating (measuring) the film thickness of an epitaxial film formed on the upper surface of a Si substrate.
Method, cross-section SEM, Schottky method (MOS diode method), and FTIR method were used.

[0003]

However, the SIMS method has a problem that it takes time to evaluate the film thickness at one point. Further, the cross-section SEM has a problem that it can be applied only when the conductivity type of the epitaxial film is different from the conductivity type of the underlying film, and there is a problem that the substrate must be broken because the cross-section of the substrate needs to be observed. It was

Further, in the Schottky method and the MOS diode method, when the impurity concentration of the epitaxial film is high, the electric field reaches a breakdown electric field strength when a voltage is applied, and a breakdown occurs until the depletion layer reaches the substrate. There was a problem that the thickness could not be evaluated. In addition, in the case of the Schottky method and the MOS diode method, there is a problem that an electrode for measurement needs to be additionally provided.

The FTIR method is a method capable of nondestructively and optically measuring the film thickness of an epitaxial film. However, since the impurity concentration and the film thickness of the epitaxial film that can be measured are limited, there is a problem that the measurement cannot be performed if the impurity concentration is high or the film thickness is thin.

On the other hand, when manufacturing a SiC (silicon carbide) semiconductor device (for example, an EC-FET), it is very important to control the film thickness of the channel epitaxial film, but the film thickness of the epitaxial film is measured during the manufacturing process. I couldn't do it at one point. Of course, it was not possible to confirm the film thickness distribution of the channel epitaxial film (n-layer) in the surface of the SiC substrate, which requires measuring the film thickness at several points.

Therefore, an object of the present invention is to provide a method for manufacturing a semiconductor device, a method for measuring the thickness of an epitaxial film, and a semiconductor device, in which the film thickness of the epitaxial film can be easily measured even during the manufacturing process. Especially.

[0008]

According to the invention of claim 1, a step of forming a concave portion or a convex portion on the upper surface of the semiconductor substrate, and homoepitaxy on the upper surface of the semiconductor substrate to carry out homoepitaxial film and defects. Forming a layer and
Since it has a step of measuring the film thickness of the homoepitaxial film based on measuring the length dimension of the defect layer in the off direction, it is possible to measure the film thickness of the homoepitaxial film even during the manufacturing process. It is easily possible. here,
The fact that the thickness of the homoepitaxial film can be calculated based on the length dimension of the defect layer in the off direction is an experimental and theoretical finding of the present invention.

According to the second aspect of the present invention, the off angle of the semiconductor substrate is 1 degree or more and 1 with respect to the C axis of the semiconductor substrate.
Since it is set to 0 degrees or less, the defect layer can be reliably formed on the upper surface of the semiconductor substrate.

In this case, it is preferable that the semiconductor substrate is a SiC substrate having a crystal form of 4H, 6H, 15R, as in the invention of claim 3.

According to the invention of claim 4, the depth dimension of the concave portion or the height dimension of the convex portion is set to 0.1 μm or more, so that a measurable defect layer is reliably formed on the upper surface of the semiconductor substrate. can do.

According to the fifth aspect of the present invention, since the pattern shape of the concave portion or the convex portion is set to be rectangular, it is possible to prevent the useless space from being generated on the upper surface of the semiconductor substrate.

According to the invention of claim 6, the direction of the long side of the rectangular pattern shape of the concave portion or the convex portion is set within the range of 45 to 135 degrees with respect to the off direction of the semiconductor substrate. Therefore, the defect layer can be reliably formed on the upper surface of the semiconductor substrate.

According to the invention of claim 7, the direction of the long side of the rectangular pattern shape of the concave portion or the convex portion is configured to be substantially perpendicular to the off direction of the semiconductor substrate. When the length of the defect layer having a trapezoidal pattern and extending in a direction perpendicular to the stepped portion of the concave or convex portion is measured, the film thickness of the homoepitaxial film is calculated based on the measured length. Can be (measured).

According to the invention of claim 8, since the pattern shape of the concave portion or the convex portion is set to be circular, the film thickness of the homoepitaxial film can be measured and the off direction of the semiconductor substrate can be determined. .

According to the ninth aspect of the present invention, since the plurality of recesses or protrusions are formed on the upper surface of the semiconductor substrate, the film thickness of the homoepitaxial film at a plurality of points can be measured.

In a tenth aspect of the present invention, the pattern shape of the plurality of recesses or protrusions is formed in a rectangular shape, and the long sides of the rectangles of the plurality of recesses or protrusions are made different and close to each other. Since the layers are arranged, the film thickness of the homoepitaxial film can be roughly estimated by visually recognizing the pattern shapes of the plurality of defect layers. This is because if the length of the long side of the rectangle is short, the pattern shape of the defect layer becomes a triangle, and if the length of the long side of the rectangle is long, the pattern shape of the defect layer becomes a trapezoid. With this configuration, the film thickness of the homoepitaxial film can be approximately estimated from the pattern shapes of the plurality of defect layers without measuring the length of the defect layer.

According to the eleventh aspect of the present invention, since the pattern shape of the plurality of recesses or protrusions is formed in a rectangular shape and the plurality of recesses or protrusions are arranged at different intervals, the length of the defect layer can be reduced. The thickness of the homoepitaxial film can be almost estimated by visually observing whether or not the defective layer is in contact with the adjacent concave portion or convex portion, even if it is not measured.

According to the twelfth aspect of the invention, since the thickness of the homoepitaxial film is set to 50 nm or more,
A measurable defect layer can be reliably formed on the upper surface of the semiconductor substrate.

According to the thirteenth aspect of the present invention, it is possible to obtain substantially the same operational effect as the first aspect of the invention.

According to the fourteenth aspect of the present invention, the step of forming a recess in the upper surface of the semiconductor substrate, and the step of performing homoepitaxy on the upper surface of the semiconductor substrate to form a homoepitaxial film and a defect layer, Since it comprises a step of filling the recess with an epitaxial film and a step of polishing the upper surface of the semiconductor substrate until the defect layer disappears, it is easy to determine whether or not the filling of the recess with the homoepitaxial film is completed. In addition, since the defective layer serves as a film thickness monitor of the polishing amount, it is possible to prevent over-etching of the polishing amount.

According to the fifteenth and sixteenth aspects of the invention, it is possible to obtain substantially the same operational effects as those of the second and third aspects of the invention.

According to the seventeenth aspect of the present invention, when the structure of the semiconductor substrate is an n− / n + structure, an abnormal in-plane film thickness of the n− layer can be determined during the manufacturing process.

According to the eighteenth aspect of the invention, since the depth dimension of the recess is set to 0.5 μm or more, the buried layer can be left after polishing.

According to the nineteenth, twenty, twenty-first and twenty-second aspects of the present invention, it is possible to obtain substantially the same operational effects as those of the fifth, seventh, eighth and ninth aspects.

According to the invention of claims 23 and 24,
It is possible to obtain substantially the same operational effect as the invention of claim 1.

Furthermore, the claims 25, 26, 27 and 2 are
According to the inventions of 8, 29, 30, 31, claims 2, 3,
It is possible to obtain substantially the same operational effects as the inventions of 4, 5, 8, 6, and 7.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment in which the present invention is applied to a SiC semiconductor device will be described below with reference to FIGS. 1 to 3. In this embodiment, as shown in FIGS. 1 and 2, for example, a SiC substrate (SiC wafer) 1 is used as a semiconductor substrate.
Is a SiC substrate having a crystal form of 4H, for example, and has a predetermined off angle θ.

Here, one axis 2 forming the off angle θ is the C axis, and this C axis 2 is (000
1) A normal to the crystal plane (see the broken line in FIGS. 1 and 2). The other axis 3 forming the off angle θ is a normal line to the surface (upper surface) of the SiC substrate 1. In the case of the present embodiment, the off angle θ is set to be, for example, 1 degree or more and 10 degrees or less with respect to the C axis 2 of the SiC substrate 1.

Now, in the case where a semiconductor process for manufacturing a predetermined device (chip) on the upper surface of the SiC substrate 1 is performed, the homoepitaxial film 4 (see FIGS. 1C and 2) is formed on the upper surface of the SiC substrate 1. When it is necessary to form the film, the film thickness t of the homoepitaxial film 4 is measured as described below.

In this case, before forming the homoepitaxial film 4, as shown in FIGS. 1A and 1B, a recess 5 is formed on the upper surface of the SiC substrate 1 whose off-angle θ is known, for example, RIE. It is formed by the processing method of (Step 1). still,
The position where the recess 5 is formed is the SiC substrate 1 (that is, S
Any position may be used as long as it is the upper surface of the iC wafer), and it may be outside the region where the device (chip) is formed.
It may be inside. Further, the pattern shape of the recess 5 is an elongated rectangle (that is, a groove shape) as shown in FIG. The long side of the rectangular pattern is arranged to be substantially perpendicular to the off direction A of the SiC substrate 1.

Further, the depth dimension of the recess 5 may be set to, for example, 0.1 μm or more. Here, the recess 5
The depth dimension is more preferably set to 0.5 μm or more, for example.

Next, homoepitaxy is performed on the upper surface of the SiC substrate 1 to form the homoepitaxial film 4 and the defect layer 6 (step 2). In this case, the reason why the defect layer 6 is formed at the same time as the homoepitaxial film 4 is that there is no a-plane information in the left corner (step) of the recess 5 in FIG.
This is because the (0001) facet surface (the surface having no off angle) is generated and the defect layer 6 is generated thereon. The defect layer 6 is SiC having a crystal form of 3C, for example. In the case of this configuration, the stepped portion on the left side of the recess 5 in FIG. 1 can be called a stepped portion that becomes higher on the downstream side of the step flow, and it can be said that the defect layer 6 is generated from this stepped portion.

The homoepitaxial film 4 is formed by CVD growth in the range of 1200 to 1700 ° C., for example. In this case, it has been experimentally confirmed that when the temperature is set to 1200 ° C. or lower, the defective layer is generated also in the portions other than the step portion, and when the temperature is set to 1700 ° C. or higher, the defect layer is hard to generate from the step portion. It has been confirmed by experiments.

Furthermore, when a micrograph of the upper surface of the SiC substrate 1 is taken, the surface irregularities in the region of the defect layer 6 are different from the irregularities in the region of the homoepitaxial film 4. That is, since the defect layer 6 has large surface irregularities, it can be easily visually recognized by, for example, an SEM or an optical microscope.

When the homoepitaxial film is formed by performing homoepitaxy, the film thickness of the homoepitaxial film 4 is preferably set to 50 nm or more. With this structure, when the off angle θ is 8 degrees, the defect layer 6
Has a dimension L (length in the direction along the off direction A) of 366
Since it becomes nm or more, the defect layer 6 can be measured by SEM.
Further, when the film thickness of the homoepitaxial film 4 is set to 300 nm or more, when the off angle θ is 8 degrees, the dimension L of the defect layer 6 becomes 2.1 μm or more, and the defect layer 6 can be measured with an optical microscope.

Then, in this embodiment, the thickness t of the homoepitaxial film 4 is obtained (measured) by the calculation described later based on the measurement of the length dimension L of the defect layer 6 in the off direction A ( Step 3). In this case, of the length dimension L of the defect layer 6 in the off-direction A, if the length dimension extending from the opening of the recess 5 in the off-direction A is L ', this length dimension L'and the homoepitaxial film. The following relational expression holds theoretically between the film thickness t of 4 and the off angle θ.

Tan θ = t / L ' Therefore, t = L ′ × tan θ Then, the film thickness t can be calculated.

Here, it is actually possible to distinguish the length dimension L of the defect layer 6 in the off direction A from the length dimension L'extending from the opening of the recess 5 in the off direction A with a microscope (photograph). Is quite difficult to do. Further, it is known that when the width dimension of the recess 5 in the off direction is small or when the depth dimension of the recess 5 is shallow, the difference α between L and L ′ does not become larger than a certain value. Further, when the off angle θ is, for example, 8 degrees, L and L '
It has been found that the difference α between and is about 15% at the maximum.

Therefore, practically, it was confirmed by experiments that there is no problem even if the film thickness t is calculated by using L instead of L ′, that is, by the following equation t = L × tan θ. ing.

Therefore, in this embodiment, after the dimension L of the defect layer 6 is measured, the film thickness t of the homoepitaxial film 4 is calculated by the following formula t = L × tan θ.

According to this embodiment having such a structure, Si
After forming the recess 5 on the upper surface of the C substrate 1, homoepitaxy is performed on the upper surface of the SiC substrate 1 to form the homoepitaxial film 4 and the defect layer 6, and the length dimension of the defect layer 6 in the off direction. Since the film thickness t of the homoepitaxial film 4 is calculated based on the measurement of L, that is, the film thickness t is measured, the film thickness t of the homoepitaxial film 4 is measured even during the manufacturing process (semiconductor process). The t can be measured easily and quickly.

Further, in the above embodiment, the off angle θ of the SiC substrate 1 is set to 1 degree or more and 10 degrees or less with respect to the C axis 3 of the SiC substrate 1, so that the defect layer 6 is formed on the upper surface of the SiC substrate 1. Can be reliably formed. It has been confirmed by experiments that if the off angle θ is set to be less than 1 degree or more than 10 degrees, the defect layer is not properly generated.

Further, in the above embodiment, since the depth dimension of the recess 5 is set to 0.1 μm or more, the measurable defect layer 6 can be reliably formed on the upper surface of the SiC substrate 1.
In this case, the dimension L of the defect layer 6 can be measured by SEM, for example. Here, if the depth dimension of the recess 5 is set to 0.5 μm or more, the dimension L of the defect layer 6 can be measured by an optical microscope.

Further, in the above embodiment, as shown in FIG. 3, since the pattern shape of the recess 5 is rectangular, the pattern shape of the defect layer 6 becomes trapezoidal, and the size of the recess 5 and the size of the defect layer 6 are formed. Can be the minimum required size. As a result, it is possible to prevent the useless space (the space dedicated to the measurement of the film thickness t) from being generated on the upper surface of the SiC substrate 1 as much as possible, which is advantageous for device (chip) production.

Further, in the above embodiment, the long side of the rectangular pattern shape of the recess 5 is arranged to be substantially perpendicular to the off direction A of the SiC substrate 1, so that the pattern shape of the defect layer 6 is formed. Is a trapezoid, and the length L of the defect layer 6 extending in the direction perpendicular to the step of the recess 5 is measured,
The film thickness t of the homoepitaxial film 4 can be calculated (measured) based on the measured length L.

FIG. 4 shows a second embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals. In the second embodiment, the pattern shape of the concave portion 7 is a triangle, and the long side of the triangle is SiC.
It was configured to be substantially perpendicular to the off direction A of the substrate 1. As a result, also in the second embodiment, the defect layer 6 having substantially the same pattern shape (that is, trapezoidal shape) as in the first embodiment is generated.

The structure of the second embodiment other than that described above is the same as the structure of the first embodiment. Therefore, also in the second embodiment, it is possible to obtain the same effect as that of the first embodiment. The pattern shape of the recesses 5 and 7 is not limited to a rectangle or a triangle, but may be another shape such as a polygon.

FIG. 5 shows a third embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals. In the third embodiment, the direction of the long side of the rectangular pattern of the recess 5 is tilted with respect to the off direction A of the SiC substrate 1. Specifically, when the angle formed by the direction of the long side and the off direction A of the SiC substrate 1 is φ, it is configured such that 45 ° <φ <135 °. It has been confirmed by an experiment that such a structure can surely form a good defect layer 8. It has been confirmed by experiments that if the angle φ is set to 45 degrees or less or 135 degrees or more, the defect layer is not formed well.

Also in the case of the above structure, the film thickness t of the homoepitaxial film 4 can be calculated by measuring the dimension L of the defect layer 8 shown in FIG. The configuration of the third embodiment other than the above is the same as the configuration of the first embodiment. Therefore, also in the third embodiment, it is possible to obtain the same effect as that of the first embodiment.

FIG. 6 shows a fourth embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals. In the fourth embodiment, the pattern shape of the recess 9 is set to be circular. According to this configuration, the SiC substrate 1
Even if the off direction A is unknown, the defect layer 10 is generated in the direction opposite to the off direction A. Therefore, the off direction of SiC substrate 1 is known. Then, the length dimension L of the defect layer 10 in the direction along the off direction A can be measured, and the film thickness of the homoepitaxial film 4 can be calculated (measured) based on this dimension L.

The structure of the fourth embodiment other than the above is the same as the structure of the first embodiment. Therefore, also in the fourth embodiment, it is possible to obtain the same effect as that of the first embodiment.

FIG. 7 shows a fifth embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals. In the fifth embodiment, as shown in FIG.
A plurality of, for example, four recesses 5 are formed on the iC substrate (SiC wafer) 1. The configuration of the fifth embodiment other than the above is the same as the configuration of the first embodiment.

Therefore, also in the fifth embodiment, it is possible to obtain the same effect as that of the first embodiment. In particular, according to the fifth embodiment, since the plurality of recesses 5 are formed on the upper surface of the SiC substrate 1, it is possible to measure the film thickness of the homoepitaxial film 4 at a plurality of points during the manufacturing process. It is possible to detect the abnormal distribution of the thickness of the homoepitaxial film 4.

FIG. 8 shows a sixth embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals. In the sixth embodiment, as shown in FIG.
A plurality of, for example, five recesses 5 are formed in a region other than the device pattern on the iC substrate (SiC wafer) 1. The configuration of the sixth embodiment other than the above is the same as the configuration of the first embodiment.

Therefore, also in the sixth embodiment, it is possible to obtain the same effect as that of the first embodiment. Particularly, according to the sixth embodiment, it is possible to measure the film thickness of the homoepitaxial film 4 at a plurality of points during the manufacturing process,
It is possible to detect an abnormal film thickness distribution and prevent the device pattern from being adversely affected.

9 and 10 show a seventh embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals. In the seventh embodiment, as shown in FIG. 9, a plurality of, for example, three rectangular recesses 5a, 5b, 5c are formed on the SiC substrate 1, and the plurality of recesses 5a, 5b, 5c are rectangular. The lengths of the long sides of the are different from each other and are arranged close to each other. In the case of this structure, the film thickness t of the homoepitaxial film 4 can be obtained by visually recognizing the respective pattern shapes of the three defect layers 6a, 6b, 6c.
Can be roughly estimated.

Specifically, first, Si having an off angle θ of 8 degrees
For the C substrate 1, the relationship between the length dimension L of the defect layer 6 and the film thickness t of the homoepitaxial film 4 is investigated, and Table 1 below is prepared. In this case, tan θ = t / L holds.

[0059]

[Table 1]

Next, when the film thickness t of the homoepitaxial film 4 is 1.0 μm, the length dimension K (see FIG. 10) of the recess 5 when the pattern shape of the defect layer 6 is a triangle is obtained. The length dimension K can be calculated by the following formula.

K = 2 × L × tan β Here, the angle β shown in FIG. 10 changes depending on the CVD growth condition, but in the experiment by the applicant, it was, for example, 22 degrees, so K was calculated under this condition. I tried to. Further, from Table 1 above, when the film thickness t is 1.0 μm, the length dimension L of the defect layer 6 is
Is 7.1 μm. Therefore, K = 5.7 μm was calculated. Subsequently, each K when the film thickness t was 2.0 μm and 3.0 μm was calculated, and Table 2 below was created.

[0062]

[Table 2]

Then, the three recesses 5a, 5 shown in FIG.
Set the length dimensions K1, K2, and K3 of b and 5c to 1
Assuming that the thickness is 7.2 μm, 11.5 μm, and 5.7 μm, the following table 3, that is, the determination table, can be obtained from the above table 2.

[0064]

[Table 3]

Therefore, in the case of the state shown in FIG. 9, it can be seen simply that the film thickness t of the homoepitaxial film 4 is more than 1.0 μm and less than 2.0 μm.
That is, with this configuration, the defect layers 6a, 6b, 6c
Of the plurality of defect layers 6a, 6b, 6 without measuring the length of
The film thickness t of the homoepitaxial film 4 can be estimated almost accurately by each pattern shape of c.

On the other hand, like the eighth embodiment of the present invention shown in FIG. 11, a plurality of, for example, four recesses 5d, 5e, 5f, 5 are formed.
The pattern shape of g is formed into a rectangle, and these 4
Whether or not the individual recesses 5d, 5e, 5f, and 5g are arranged at different intervals and whether the defect layers contact adjacent recesses without measuring the lengths of the defect layers 6d, 6e, 6f, and 6g. By visually observing, it is possible to estimate the film thickness t of the homoepitaxial film 4 almost accurately.

The reason is that the four recesses 5 shown in FIG.
Intervals d1, d2, d3 of d, 5e, 5f, 5g
Are 7.1 μm, 14.2 μm and 21.3 μm, respectively.
Then, from Table 2 above, the following Table 4, that is, the determination table is obtained.

[0068]

[Table 4]

Therefore, in the case of the state shown in FIG. 11, it can be seen simply that the film thickness t of the homoepitaxial film 4 is more than 1.0 μm and less than 2.0 μm.
That is, with this structure, the defect layers 6d, 6e, 6
Even if the lengths of f and 6g are not measured, a plurality of defect layers 6d,
By visually recognizing each pattern shape of 6e, 6f, and 6g, the film thickness t of the homoepitaxial film 4 can be estimated almost accurately.

In each of the above embodiments, the recesses 5, 7, 9 for measuring the thickness of the homoepitaxial film 4 are formed on the upper surface of the SiC substrate 1, but the present invention is not limited to this. Instead, a convex portion for film thickness measurement may be formed. Even if this convex portion is formed, a defect layer is generated as in the case of the concave portion, and the length dimension L of this defective layer is
The film thickness t of the homoepitaxial film 4 can be measured based on the measurement of. The pattern shape, protrusion size, etc. of the convex portion may be set in substantially the same manner as the pattern shape, depth dimension, etc. of the concave portion.

Further, in each of the above embodiments, the crystal form is applied to the SiC substrate 1 of 4H, but the present invention is not limited to this, and it may be applied to the SiC substrate of the crystal form of 6H or 15R. Further, in the case where the structure of the SiC substrate is an n− / n + structure, when the n− layer is formed by epitaxy, if the above-mentioned concave portion for film thickness measurement is formed, n
-It becomes possible to determine the in-plane film thickness abnormality of the layer during the manufacturing process.

12 and 13 show a ninth embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals. In the ninth embodiment, the homoepitaxial film is embedded in the recess 5.

Specifically, as shown in FIGS. 12A and 12B, a SiC substrate 11 having, for example, an n− / n + structure is prepared, and a recess is formed on the upper surface of (the n− layer of) this SiC substrate 11. 5 is formed (step 1). In this case, as shown in FIG. 13, the recess 5 has a plurality of square pattern shapes. The direction of one side of the square recess 5 is
It is configured to be substantially perpendicular to the off direction A of the SiC substrate 11.

Then, as shown in FIG.
Homoepitaxy is performed on the upper surface of the C substrate 11 to form, for example, a P-type homoepitaxial film 4 and a defect layer 6, and the recess 5 is filled with the homoepitaxial film 4 (step 2). In this case, the homoepitaxy conditions are almost the same as in the case of the first embodiment (the CVD growth conditions for generating the defect layer 6), and only the film thickness is set to such an extent that the recess 5 can be filled. There is.

Then, by measuring the length dimension L of the defect layer 6, the film thickness of the homoepitaxial film (that is, the buried epitaxial layer) 4 is measured. Then, by measuring this film thickness, it is possible to accurately determine whether or not the filling into the recess 5 is completed.

Subsequently, as shown in FIG. 12D, the upper surface of the SiC substrate 11 is polished (etched) until the defect layer 6 disappears (step 3). In this case, since the defect layer 6 serves as a film thickness monitor of the polishing amount, it becomes easy to control the polishing amount. As a result, overetching can be prevented. Further, the step of forming the polishing stop mark can be omitted.

The structure of the ninth embodiment other than that described above is the same as the structure of the first embodiment. Therefore, also in the ninth embodiment, it is possible to obtain substantially the same operational effects as in the first embodiment.

FIG. 14 shows a tenth embodiment of the present invention. The same parts as those in the ninth embodiment are designated by the same reference numerals. In the tenth embodiment, the pattern shape of the recess 5 is substantially hexagonal. And this 6
The direction of one side of the rectangular recess 5 is configured to be substantially perpendicular to the off direction A of the SiC substrate 11. The configuration of the tenth embodiment other than the above is the same as the configuration of the ninth embodiment. Therefore, also in the tenth embodiment, it is possible to obtain substantially the same operational effects as those of the ninth embodiment.

FIG. 15 shows the 11th embodiment of the present invention. The same parts as those in the ninth embodiment are designated by the same reference numerals. In the eleventh embodiment, the pattern shape of the recess 5 is circular. With this configuration, Si
Even if the off direction of the C substrate 11 is unknown, the defect layer 6 can be surely generated.

The structure of the eleventh embodiment other than the above is the same as the structure of the ninth embodiment. Therefore, also in the eleventh embodiment, it is possible to obtain substantially the same operational effects as those of the ninth embodiment.

In each of the above embodiments, the semiconductor substrate is, for example, a SiC substrate (that is, a SiC semiconductor device).
However, instead of this, an ordinary Si substrate (ie,
Si semiconductor device).

[Brief description of drawings]

FIG. 1 is a view showing a manufacturing process of a semiconductor device showing a first embodiment of the present invention.

FIG. 2 is a cutaway perspective view of a SiC substrate.

FIG. 3 is a partial top view of a SiC substrate.

FIG. 4 is a diagram corresponding to FIG. 3 showing a second embodiment of the present invention.

FIG. 5 is a view corresponding to FIG. 3 showing a third embodiment of the present invention.

FIG. 6 is a view corresponding to FIG. 3 showing a fourth embodiment of the present invention.

FIG. 7 is a top view of the entire SiC substrate showing the fifth embodiment of the present invention.

FIG. 8 is a view corresponding to FIG. 7 showing a sixth embodiment of the present invention.

FIG. 9 is a view corresponding to FIG. 3 showing a seventh embodiment of the present invention.

FIG. 10 is a view corresponding to FIG.

FIG. 11 is a view corresponding to FIG. 9 showing an eighth embodiment of the present invention.

FIG. 12 is a view corresponding to FIG. 1 showing a ninth embodiment of the present invention.

FIG. 13 is a top view of a SiC substrate

FIG. 14 is a view corresponding to FIG. 13 showing a tenth embodiment of the present invention.

FIG. 15 is a view corresponding to FIG. 13 showing an eleventh embodiment of the present invention.

[Explanation of symbols]

1 is a SiC substrate (semiconductor substrate), 2 is a C-axis, 4 is a homoepitaxial film, 5 is a recess, 6 is a defect layer, 7 is a recess, 8
Indicates a defect layer, 9 indicates a concave portion, 10 indicates a defect layer, and 11 indicates a SiC substrate.

Claims (31)

[Claims] 1. A method of manufacturing a semiconductor device having a structure in which a homoepitaxial film is formed on an upper surface of a semiconductor substrate having an off-angle, the step of forming a concave portion or a convex portion on the upper surface of the semiconductor substrate; Forming a homoepitaxial film and a defect layer by performing homoepitaxy on the upper surface of the substrate, and measuring the thickness of the homoepitaxial film based on measuring the length dimension of the defect layer in the off direction. A method of manufacturing a semiconductor device, comprising: 2. The method of manufacturing a semiconductor device according to claim 1, wherein the off-angle of the semiconductor substrate is set to 1 degree or more and 10 degrees or less with respect to the C axis of the semiconductor substrate. 3. The semiconductor substrate has a crystal form of 4H, 6
3. The method for manufacturing a semiconductor device according to claim 1, wherein the H, 15R SiC substrate is used. 4. The method of manufacturing a semiconductor device according to claim 1, wherein the depth dimension of the concave portion or the height dimension of the convex portion is set to 0.1 μm or more. 5. The pattern shape of the concave portion or the convex portion,
5. The method for manufacturing a semiconductor device according to claim 1, wherein the method is set to be rectangular. 6. A structure in which the long side of the rectangular pattern shape of the concave or convex is within the range of 45 to 135 degrees with respect to the off direction of the semiconductor substrate. 5. The method for manufacturing a semiconductor device according to 5. 7. The semiconductor according to claim 6, wherein the direction of the long side of the rectangular pattern shape of the concave portion or the convex portion is substantially perpendicular to the off direction of the semiconductor substrate. Device manufacturing method. 8. The pattern shape of the concave portion or the convex portion,
5. The method for manufacturing a semiconductor device according to claim 1, wherein the semiconductor device is formed in a circular shape. 9. The plurality of recesses or protrusions are formed on the upper surface of the semiconductor substrate.
9. A method of manufacturing a semiconductor device according to any one of items 8 to 8. 10. The pattern shape of the plurality of recesses or protrusions is formed in a rectangular shape, and the lengths of the long sides of the rectangles of the plurality of recesses or protrusions are arranged differently and close to each other. The method for manufacturing a semiconductor device according to claim 9. 11. The method for manufacturing a semiconductor device according to claim 9, wherein the plurality of recesses or protrusions are formed in a rectangular pattern shape, and the plurality of recesses or protrusions are arranged at different intervals. . 12. The film thickness of the homoepitaxial film is:
The method for manufacturing a semiconductor device according to claim 1, wherein the thickness is set to 50 nm or more. 13. A step of forming a concave portion or a convex portion on an upper surface of a semiconductor substrate having an off angle, a step of performing homoepitaxy on the upper surface of the semiconductor substrate to form a homoepitaxial film and a defect layer, And a step of measuring the film thickness of the homoepitaxial film based on measuring the length dimension of the defect layer in the off direction. 14. A method of manufacturing a semiconductor device having a structure of forming a homoepitaxial film on an upper surface of a semiconductor substrate having an off angle, comprising: forming a recess on the upper surface of the semiconductor substrate; The method comprises performing homoepitaxy to form a homoepitaxial film and a defect layer, filling the recess with the homoepitaxial film, and polishing the upper surface of the semiconductor substrate until the defect layer disappears. A method of manufacturing a semiconductor device, comprising: 15. The method of manufacturing a semiconductor device according to claim 14, wherein the off-angle of the semiconductor substrate is set to 1 degree or more and 10 degrees or less with respect to the C-axis of the semiconductor substrate. 16. The semiconductor substrate has a crystalline form of 4H, 6
16. The method of manufacturing a semiconductor device according to claim 14, wherein the H, 15R SiC substrate is used. 17. The structure of the semiconductor substrate is n− / n +.
The method of manufacturing a semiconductor device according to claim 16, wherein the method is a structure. 18. The method of manufacturing a semiconductor device according to claim 14, wherein the depth of the recess is set to 0.5 μm or more. 19. The method for manufacturing a semiconductor device according to claim 14, wherein the pattern shape of the recess is set to be a polygon. 20. One of the polygonal pattern shapes of the recesses
2. A structure in which the direction of one side is substantially perpendicular to the off direction of the semiconductor substrate.
9. The method for manufacturing a semiconductor device according to 9. 21. The method for manufacturing a semiconductor device according to claim 14, wherein the pattern shape of the recess is set to be circular. 22. The method of manufacturing a semiconductor device according to claim 14, wherein a plurality of the recesses are formed on the upper surface of the semiconductor substrate. 23. A semiconductor device comprising a homoepitaxial film formed on an upper surface of a semiconductor substrate having an off angle, wherein a step portion formed on the upper surface of the semiconductor substrate so that a step flow downstream side becomes higher, A semiconductor device comprising: a homoepitaxial film formed by performing homoepitaxy on an upper surface of a semiconductor substrate; and a defect layer formed so as to be generated from the step portion. 24. The semiconductor device according to claim 23, wherein the step portion is formed by a concave portion or a convex portion formed on the upper surface of the semiconductor substrate. 25. The semiconductor device according to claim 23, wherein the off-angle of the semiconductor substrate is set to 1 degree or more and 10 degrees or less with respect to the C axis of the semiconductor substrate. 26. The semiconductor substrate has a crystal form of 4H or 6
26. The semiconductor device according to claim 23, which is a H, 15R SiC substrate. 27. The semiconductor device according to claim 23, wherein the depth dimension of the concave portion or the height dimension of the convex portion is set to 0.1 μm or more. 28. The semiconductor device according to claim 23, wherein the pattern shape of the concave portion or the convex portion is set to a rectangle. 29. The semiconductor device according to claim 23, wherein the pattern shape of the concave portion or the convex portion is set to be circular. 30. The semiconductor according to claim 23, wherein a direction of the step portion is configured to be within a range of 45 to 135 degrees with respect to an off direction of the semiconductor substrate. apparatus. 31. The semiconductor device according to claim 23, wherein a direction of the step portion is configured to be in a range substantially perpendicular to an off direction of the semiconductor substrate.