JP2006269960A - Method of cleaning semiconductor substrate and method of manufacturing semiconductor substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of cleaning a semiconductor substrate which improves the cleanliness factor of surface of the semiconductor substrate, and which is capable of avoiding the generation of variety in roughness on the surface of the semiconductor substrate, and to provide a method of manufacturing the semiconductor substrate. <P>SOLUTION: The method of cleaning a semiconductor substrate is provided with an HF (Hydrogen Fluoride) treatment process (treatment S23) for cleaning the semiconductor substrate with HF water solution, and an ozone treatment process (treatment S25) for cleaning the semiconductor substrate with ozone water consisting of deionized water and ozone contained therein after the HF treatment process (treatment S23). Further, a deionized water treatment process (treatment S24) for cleaning the semiconductor substrate with deionized water is provided between the HF treatment process (treatment S23) and the ozone treatment process (treatment S25). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor substrate cleaning method and a semiconductor substrate manufacturing method.

In recent years, with the miniaturization and high integration of semiconductor devices, the influence of the surface contamination of the semiconductor substrate on the manufacturing yield, device characteristics, and reliability is increasing. In particular, fine particles, metal impurities, organic substances, etc. are likely to adhere to the surface of the semiconductor substrate after the finishing process for mirror polishing the semiconductor substrate is performed. For this reason, a cleaning method for removing the adhered fine particles, metal impurities, organic substances, etc. after the semiconductor substrate has been finished has been proposed (for example, see Patent Document 1).
The semiconductor substrate cleaning method described in Patent Document 1 is a method in which a semiconductor substrate is immersed in an aqueous HF solution and then immersed in an aqueous ozone solution. By such a cleaning method, after removing fine particles, metal impurities, organic substances, or the like adhering on the surface of the semiconductor substrate, a uniform oxide film is formed on the surface of the semiconductor substrate.

JP 2002-118088 A

  However, in the semiconductor substrate cleaning method described in Patent Document 1, the HF aqueous solution remains on the surface of the semiconductor substrate after the semiconductor substrate is immersed in the HF aqueous solution. When the semiconductor substrate is immersed in the ozone aqueous solution with the HF aqueous solution residue on the surface of the semiconductor substrate in this manner, the residue of the HF aqueous solution reacts with ozone in the ozone aqueous solution, and the surface of the semiconductor substrate is roughened (HAZE). ). Thus, when unevenness of roughness occurs on the surface of the semiconductor substrate, it may be handled as a defective product in the appearance inspection of the semiconductor substrate. In particular, a semiconductor substrate that is treated as a defective product in appearance inspection appears remarkably when it is cleaned by a single wafer cleaning method or when the dopant concentration of the semiconductor substrate is high.

  An object of the present invention is to provide a method for cleaning a semiconductor substrate and a method for manufacturing a semiconductor substrate, which can improve the cleanliness of the surface of the semiconductor substrate and avoid the occurrence of uneven roughness on the surface of the semiconductor substrate.

  According to a first aspect of the present invention, there is provided a semiconductor substrate cleaning method comprising: an HF processing step for cleaning a semiconductor substrate with an HF aqueous solution; and ozone water in which ozone is contained in pure water after the HF processing step. A cleaning method for a semiconductor substrate comprising an ozone treatment step for performing a cleaning treatment at a step, comprising a pure water treatment step for washing the semiconductor substrate with pure water between the HF treatment step and the ozone treatment step. It is characterized by being.

  The method for cleaning a semiconductor substrate according to claim 2 of the present invention is the method for cleaning a semiconductor substrate according to claim 1, wherein the semiconductor substrate is made of a material having a resistivity of 1 Ω · cm or less. And

  The semiconductor substrate cleaning method according to claim 3 of the present invention is the semiconductor substrate cleaning method according to claim 1 or 2, wherein the semiconductor substrate is cleaned with the ozone water before the HF processing step. An ozone pretreatment step is provided.

  According to a fourth aspect of the present invention, there is provided a semiconductor substrate manufacturing method comprising: a mirror processing step for mirror processing a semiconductor substrate; and a vapor phase growth processing step for vapor-phase-growing an epitaxial film on the semiconductor substrate surface. Then, the semiconductor substrate cleaning method according to any one of claims 1 to 3 is performed.

  According to the semiconductor substrate cleaning method of the first aspect, since the pure water treatment step is performed after the HF treatment step, residues of the HF aqueous solution remaining on the semiconductor substrate can be removed by the pure water treatment step. For this reason, even if the ozone treatment step is performed, the residue of the HF aqueous solution and the ozone in the ozone water do not react on the surface of the semiconductor substrate, and unevenness of roughness occurs on the surface of the semiconductor substrate. Can be avoided. Therefore, it is possible to improve the cleanliness of the surface of the semiconductor substrate in the HF treatment step and the ozone treatment step, and to carry out the pure water treatment step between the HF treatment step and the ozone treatment step, thereby reducing the roughness on the surface of the semiconductor substrate. Unevenness can be avoided, and it will not be defective in appearance inspection.

According to the semiconductor substrate cleaning method of the second aspect, since the semiconductor substrate is made of a material having a resistivity of 1 Ω · cm or less, the following effects can be obtained.
Semiconductor substrates tend to have different amounts of unsaturated bonds (dangling bonds) on the substrate surface depending on their resistivity.
For example, when the resistivity of the semiconductor substrate is large (the resistivity exceeds 1 Ω · cm), the amount of unsaturated bonds on the substrate surface decreases. When such a semiconductor substrate is washed with an HF aqueous solution, the residue of the HF aqueous solution captured by the unsaturated bond on the surface of the semiconductor substrate is relatively small. For this reason, it is difficult to adversely affect the roughness of the semiconductor substrate.
On the other hand, when the resistivity of the semiconductor substrate is small (the resistivity is 1 Ω · cm or less), the amount of unsaturated bonds on the substrate surface increases. When such a semiconductor substrate is washed with an HF aqueous solution, the residue of the HF aqueous solution captured by the unsaturated bond on the surface of the semiconductor substrate is relatively large. For this reason, it tends to adversely affect the roughness of the semiconductor substrate. Therefore, the cleaning method in which the pure water treatment step is performed between the HF treatment step and the ozone treatment step described above is particularly effective for washing a semiconductor substrate having a resistivity of 1 Ω · cm or less.

  According to the method for cleaning a semiconductor substrate according to claim 3, since the ozone pretreatment step is performed before the HF treatment step, organic substances adhering to the semiconductor substrate surface are decomposed or adhered to the semiconductor substrate surface. It is possible to oxidize the metal. Then, a clean substrate can be obtained by removing impurities such as metal and particles from the substrate together with the substrate surface oxidized in the HF treatment step. Further, in the ozone treatment process, an oxide film is formed on the surface of the semiconductor substrate, so that a surface on which particles are difficult to adhere can be made. Therefore, an ozone pretreatment process, an HF treatment process, a pure water treatment process, and an ozone treatment By combining the steps, the cleanliness of the surface of the semiconductor substrate can be improved.

  According to the semiconductor substrate manufacturing method of the fourth aspect, the semiconductor substrate cleaning method according to any one of the first to third aspects is performed after the mirror surface processing step or the vapor phase growth processing step. , Good organic substrate with no roughness unevenness (HAZE) on the substrate surface by removing organic matter, metal, particles, etc. adhering on the substrate surface in the mirror finishing process to improve the substrate surface cleanliness Can be manufactured.

[First embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
[Configuration of semiconductor substrate cleaning equipment]
FIG. 1 is a diagram schematically showing a schematic configuration of a cleaning apparatus 1 for a semiconductor substrate W in the first embodiment.
The cleaning apparatus 1 is a so-called batch type cleaning apparatus that collectively cleans a plurality of semiconductor substrates W that have undergone mirror finishing. As illustrated in FIG. 1, the cleaning apparatus 1 includes a transport unit 2 that transports a carrier 10 that holds a plurality of semiconductor substrates W, a cleaning liquid tank 3 that stores a cleaning liquid, and a drying process that performs a drying process on the semiconductor substrate W. And a processing unit 4.
The transport unit 2 is configured to be movable to the loader 1A, the cleaning liquid tank 3, the drying processing unit 4, and the unloader 1B as shown in FIG. 1 under the control of a control device (not shown) while supporting the carrier 10. Yes.
The loader 1A is a place where the carrier 10 can be carried into the cleaning apparatus 1. The unloader 1B is a place where the carrier 10 can be carried out from the cleaning apparatus 1 to the outside.

  As shown in FIG. 1, the cleaning liquid tank 3 includes an ozone pretreatment tank 31 that can store ozone water containing ozone in pure water, an HF treatment tank 32 that can store an HF aqueous solution, and pure water. Is composed of a pure water treatment tank 33 that can store water, an ozone treatment tank 34 that can store the ozone water, and a pure water post-treatment tank 35 that can store pure water. And each of these processing tanks 31-35 is formed in the substantially container shape which can carry in the carrier 10 inside and has an opening in the upper side. Moreover, the overflow system is employ | adopted for these process tanks 31-35.

  The drying processing unit 4 performs a drying process on the cleaning liquid attached to the carrier 10 and the semiconductor substrate W by cleaning in the cleaning liquid tank 3. Various configurations can be adopted as the drying processing unit 4. For example, the carrier 10 is rotated and the cleaning liquid is removed from the carrier 10 and the semiconductor substrate W by the centrifugal force generated by the rotation, or the IPA (isopropyl alcohol) is used. It is also possible to adopt a configuration in which the drying process is performed with steam.

FIG. 2 is a cross-sectional view schematically showing a holding state of the semiconductor substrate W by the carrier 10. Specifically, FIG. 2 is a cross-sectional view of the semiconductor substrate W as viewed from a direction orthogonal to the substrate main surface or the substrate back surface.
As shown in FIG. 2, the carrier 10 includes openings 11 and 12 on the upper side and the lower side, and is configured by a substantially cylindrical member whose width dimension in the left-right direction decreases from the substantially vertical central portion toward the lower side. ing. Then, the semiconductor substrate W is inserted into the carrier 10 through the upper opening 11.
In the carrier 10, a support part 111 extending in a direction away from the upper side opening 11 is formed near the upper side opening 11, as shown in FIG. 2, and the carrier 10 is transported by the support part 111. 2 is supported.
In the carrier 10, a plurality of grooves (not shown) are formed on the cylindrical inner surface from the upper opening 11 to the lower opening 12. Then, by sliding the semiconductor substrate W into the groove through the upper opening 11 of the carrier 10, the lower end of the semiconductor substrate W comes into contact with the lower side of the carrier 10, and the semiconductor substrate W is supported inside the carrier 10. Is done.

[Method of manufacturing a semiconductor substrate]
Next, a method for manufacturing the semiconductor substrate W will be described with reference to the drawings.
FIG. 3 is a flowchart for explaining a method of manufacturing the semiconductor substrate W.
In order to manufacture the semiconductor substrate W, for example, p + and p ++ type semiconductor single crystal ingots having a resistivity of 0.1 Ω · cm or less are formed by CZ method (Czochralski process), MCZ method (Magnetic Field Applied Czochralski process). ), FZ method (Floating Zone process), the process of cutting the semiconductor single crystal ingot to cut out the semiconductor substrate W, the process of chamfering the corners of the periphery of the semiconductor substrate W, the unevenness of the semiconductor substrate W by mechanical polishing The steps of removing the stencil and increasing the parallelism are carried out. However, these steps are well-known techniques, and thus description thereof is omitted.

After the semiconductor substrate W is mirror-polished and the semiconductor substrate W is finished in a mirror shape (processing S1: mirror processing), the semiconductor substrate W is cleaned as described below (processing S2).
Organic substances, metals, particles, and the like adhere to the surface of the semiconductor substrate W after the mirror polishing process of the semiconductor substrate W in the process S1.
Then, the following process S2 is performed to remove organic substances, metals, particles, or the like attached to the surface of the semiconductor substrate W.

In process S <b> 1, the plurality of semiconductor substrates W are mirror-polished and then the plurality of semiconductor substrates W are placed in the carrier 10. And the carrier 10 is carried in in the washing | cleaning apparatus 1, and this carrier 10 is supported by the conveyance part 2 positioned by the loader 1A (process S21).
The control device of the cleaning apparatus 1 drives and controls the transport unit 2 to bring the carrier 10 into the ozone pretreatment tank 31 and immerse the carrier 10 in ozone water in the ozone pretreatment tank 31 for a predetermined time (treatment). S22: ozone pretreatment step). At this time, the plurality of semiconductor substrates W installed in the carrier 10 decomposes organic substances adhering to the surface of the semiconductor substrate W or oxidizes metal adhering to the surface of the semiconductor substrate W with ozone water. Can do. For this reason, impurities, such as a metal and a particle, are removed from the board | substrate with the HF aqueous solution in process S23 mentioned later with the oxidized board | substrate surface, and the clean semiconductor substrate W can be obtained.

  After the process S22, the control device of the cleaning device 1 drives and controls the transport unit 2, pulls up the carrier 10, and carries it out of the ozone pretreatment tank 31. After unloading, the carrier 10 is moved to the upper side of the HF processing tank 32 and is carried into the HF processing tank 32, and the carrier 10 is immersed in the HF aqueous solution in the HF processing tank 32 for a predetermined time (processing S23: HF processing). Process). At this time, the surface of the semiconductor substrate W oxidized in the process S22 is removed from the plurality of semiconductor substrates W installed in the carrier 10 by the HF aqueous solution, and metal, particles, and the like on the surface of the semiconductor substrate W are also removed. .

After the processing S23, the control device of the cleaning device 1 drives and controls the transport unit 2, pulls up the carrier 10, and carries it out of the HF processing tank 32. After unloading, the carrier 10 is moved to the upper side of the pure water treatment tank 33 and carried into the pure water treatment tank 33, and the carrier 10 is immersed in pure water in the pure water treatment tank 33 for a predetermined time (processing S24). : Pure water treatment process). At this time, the residue of the HF aqueous solution remaining on the surface of the plurality of semiconductor substrates W installed in the carrier 10 is removed with pure water in the process S23. For this reason, on the surface of the semiconductor substrate W, the residue of the HF aqueous solution does not react with ozone in ozone water in the processing S25 described later, and unevenness of the roughness (HAZE) occurs on the surface of the semiconductor substrate W. Can be avoided. Therefore, after the semiconductor substrate W is manufactured, the semiconductor substrate W is not defective when an appearance inspection is performed.
In step S23, when the semiconductor substrate W is cleaned with the HF aqueous solution, the surface of the semiconductor substrate W is in a very active state, and contaminants are likely to adhere to the surface of the semiconductor substrate W. Therefore, in the process S24, the immersion time for immersing in pure water should be short in order to sufficiently remove the residue of the HF aqueous solution and prevent the contaminants from adhering to the surface of the semiconductor substrate W. desirable. For example, the immersion time for immersion in pure water in the process S24 is preferably 300 seconds or less.

  After the process S24, the control device of the cleaning device 1 drives and controls the transport unit 2, pulls up the carrier 10, and carries it out of the pure water treatment tank 33. After unloading, the carrier 10 is moved to the upper side of the ozone treatment tank 34 and is carried into the ozone treatment tank 34, and the carrier 10 is immersed in ozone water in the ozone treatment tank 34 for a predetermined time (process S25: ozone treatment). Process). At this time, an oxide film is formed on the surface of the plurality of semiconductor substrates W installed in the carrier 10 by ozone water. In this way, by forming an oxide film on the surface of the semiconductor substrate W, contamination of the surface of the semiconductor substrate W is prevented.

  After the process S25, the control device of the cleaning device 1 drives and controls the transport unit 2, pulls up the carrier 10, and carries it out of the ozone treatment tank 34. After unloading, the carrier 10 is moved to the upper side of the pure water post-treatment tank 35 and carried into the pure water post-treatment tank 35, and the carrier 10 is immersed in pure water in the pure water post-treatment tank 35 for a predetermined time. (Process S26). At this time, the carrier 10 and the plurality of semiconductor substrates W are washed with pure water, and ozone water attached to the carrier 10 and the plurality of semiconductor substrates W is removed in the process S25.

  After the process S26, the control device of the cleaning apparatus 1 drives and controls the transport unit 2, pulls up the carrier 10, and carries it out of the pure water post-treatment tank 35. After unloading, the carrier 10 is transported to the drying processing unit 4. The drying processing unit 4 performs a drying process for the carrier 10 and the plurality of semiconductor substrates W for a predetermined time (process S27). At this time, the pure water adhering to the carrier 10 and the plurality of semiconductor substrates W is removed in the process S27.

After the process S27, the control device of the cleaning device 1 drives and controls the transport unit 2, and transports the carrier 10 from the drying processing unit 4 to the unloader 1B. Then, the carrier 10 is carried out from the unloader 1B to the outside of the cleaning device 1 (processing S28).
The semiconductor substrate W is manufactured through the above steps.
As described above, since the cleaning process (Process S2) is performed after the mirror surface processing step (Process S1), organic substances, metals, particles, and the like attached on the substrate surface in the mirror surface processing process (Process S1) are removed. It is possible to manufacture a good semiconductor substrate W with good roughness of the substrate surface by removing and having no roughness unevenness on the substrate surface.

[Second Embodiment]
Next, a second embodiment of the present invention will be described.
In the first embodiment, a batch-type cleaning method is employed as a method for cleaning the semiconductor substrate W.
On the other hand, in the second embodiment, the cleaning liquid is supplied onto the surface of the semiconductor substrate W while being rotated around the center of the semiconductor substrate W, and the cleaning liquid on the substrate surface is diffused by the centrifugal force generated by the rotation. Thus, a so-called single wafer type spin cleaning method for cleaning the semiconductor substrate W is employed.
For example, in the pure water treatment process (process S24) described in the first embodiment, the semiconductor substrate W is rotated in the circumferential direction around the center of the semiconductor substrate W as a rotation center, and the pure water is the substrate of the semiconductor substrate W. The semiconductor substrate W is supplied to the surface, and the pure water is diffused on the substrate surface of the semiconductor substrate W by a centrifugal force by rotation, and the semiconductor substrate W is cleaned with pure water.
In this embodiment as well, as in the first embodiment, when the semiconductor substrate W is cleaned with an HF aqueous solution, the surface of the semiconductor substrate W becomes in a very active state. Is preferably a short time in order to sufficiently remove the residue of the aqueous HF solution and to prevent contaminants from adhering to the surface of the semiconductor substrate W. For example, in this embodiment, the supply time for supplying pure water is preferably 60 seconds or less.

  As described above, in the present embodiment, the semiconductor substrate W is cleaned with the cleaning liquid by supplying the cleaning liquid onto the substrate surface while the semiconductor substrate W is rotated in the circumferential direction. Easy to implement. Further, as compared with the first embodiment, since it is not necessary to move the semiconductor substrate W to each cleaning liquid tank 3, the size of the cleaning apparatus can be reduced.

Although the present invention has been described with reference to preferred embodiments, the present invention is not limited to these embodiments, and various improvements and design changes can be made without departing from the scope of the present invention. It is.
In each of the above embodiments, the cleaning process (process S2) of the semiconductor substrate W is not limited to the flow shown in FIG. In addition to the processing steps S22 to S26, other processing steps may be additionally performed. For example, an alkali cleaning process using an alkaline cleaning liquid (for example, NH4OH-H2O2-H2O mixed liquid (SC-1 (Standard Clean, Solution 1) cleaning liquid)) may be performed.

In each of the above embodiments, the configuration of the cleaning device 1 is not limited to the configuration described in each of the above embodiments, and other configurations may be employed. That is, in the first embodiment, any configuration may be adopted as long as the semiconductor substrate W is immersed in the cleaning liquid and cleaned with the cleaning liquid. In the first embodiment, the overflow method is employed. However, the present invention is not limited to this, and for example, a quick dump rinse method may be employed. Specifically, the carrier 10 including a plurality of semiconductor substrates W is installed in a single cleaning liquid tank. Then, the cleaning liquid tank is filled with a predetermined cleaning liquid, and after the predetermined time, the filled cleaning liquid is discharged. Further, the cleaning liquid tank is filled with another cleaning liquid, and after a predetermined time, the filled cleaning liquid is discharged. Such steps are sequentially performed. In the second embodiment, any structure may be adopted as long as the semiconductor substrate W is spin-cleaned with a cleaning liquid.
Moreover, in each said embodiment, you may employ | adopt suitably the ultrasonic cleaning which applies an ultrasonic wave to the semiconductor substrate W during the process process of at least any one of process process S22-26.
Furthermore, in each said embodiment, each process process S22-26 may be implemented at normal temperature, and may be implemented at other temperature.

  In each of the above-described embodiments, the cleaning process (process S2) of the semiconductor substrate W is performed after the mirror processing step S1, but not limited thereto, an epitaxial film is grown on the surface of the semiconductor substrate W by vapor phase growth. Thereafter, the object of the present invention can be sufficiently achieved even if the cleaning process (process S2) described in the above embodiments is performed.

Although the best configuration for carrying out the present invention has been disclosed in the above description, the present invention is not limited to this. That is, the invention has been illustrated and described primarily with respect to particular embodiments, but may be configured for the above-described embodiments without departing from the scope and spirit of the invention. Various modifications can be made by those skilled in the art in terms of materials, quantity, and other detailed configurations.
Therefore, the description limited to the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such is included in this invention.

Next, the effect of this invention is demonstrated based on a specific Example.
[Example 1]
In Example 1, the semiconductor substrate W was manufactured under the following manufacturing conditions by the manufacturing method described in the first embodiment.

(Production conditions)
Semiconductor substrate W; p ++ type (resistivity: 0.005 to 0.01 Ω · cm)
Ozone pretreatment process; ozone concentration: 10 to 20 ppm, immersion time: 180 to 240 sec.
HF treatment step; HF concentration: less than 5%, immersion time: 10-60 sec.
Pure water treatment process; immersion time: 10 to 60 sec.
Ozone treatment process; ozone concentration: 10 to 20 ppm, immersion time: 180 to 240 sec.
Pure water post-treatment process; immersion time 180-240 sec.

[Example 2]
In Example 2, a semiconductor substrate W was manufactured by the same method as in Example 1 except that the manufacturing conditions in Example 1 were changed as follows.
Semiconductor substrate W; p + type (Resistivity: 0.01 to 0.02Ω · cm)

[Example 3]
In Example 3, a semiconductor substrate W was manufactured by the same method as in Example 1 except that the manufacturing conditions in Example 1 were changed as follows.
Semiconductor substrate W; p-type (Resistivity: 6.02 to 24.8Ω · cm)

[Example 4]
In Example 4, the semiconductor substrate W was manufactured under the following manufacturing conditions by the manufacturing method described in the second embodiment.

(Production conditions)
Semiconductor substrate W; p ++ type (Resistivity: 0.005-0.01Ω · cm)
Ozone pretreatment process; ozone concentration: 10 to 20 ppm, supply time: 15 sec. Or more HF treatment process; HF concentration: less than 5%, supply time: 5 sec. Or less Pure water treatment process; supply time: 1 to 2 sec.
Ozone treatment process; ozone concentration: 10 to 20 ppm, supply time: 30 sec. Or more Pure water post-treatment process; not implemented

[Example 5]
In Example 5, a semiconductor substrate W was manufactured by the same method as in Example 4 except that the manufacturing conditions in Example 3 were changed as follows.
Semiconductor substrate W; p + type (Resistivity: 0.01 to 0.02Ω · cm)

[Example 6]
In Example 6, a semiconductor substrate W was manufactured by the same method as in Example 4 except that the manufacturing conditions in Example 3 were changed as follows.
Semiconductor substrate W; p-type (Resistivity: 6.02 to 24.8Ω · cm)

[Comparative Example 1]
In Comparative Example 1, the semiconductor substrate W was manufactured by performing the ozone treatment process after the HF treatment process without performing the pure water treatment process after the HF treatment process. Other steps and manufacturing conditions are the same as those in the first embodiment.

[Comparative Example 2]
In this comparative example 2, a semiconductor substrate W was manufactured by the same method as in the comparative example 1 except that the manufacturing conditions in the comparative example 1 were changed as shown below.
Semiconductor substrate W; p + type (Resistivity: 0.01 to 0.02Ω · cm)

[Comparative Example 3]
In this comparative example 3, a semiconductor substrate W was manufactured by the same method as in the comparative example 1 except that the manufacturing conditions in the comparative example 1 were changed as follows.
Semiconductor substrate W; p-type (Resistivity: 6.02 to 24.8Ω · cm)

[Comparative Example 4]
This comparative example 4 manufactured the semiconductor substrate W by performing the ozone treatment process after the HF treatment process without performing the pure water treatment process after the HF treatment process. Other steps and manufacturing conditions are the same as those in Example 3.

[Comparative Example 5]
In this comparative example 5, a semiconductor substrate W was manufactured by the same method as in the comparative example 4 except that the manufacturing conditions in the comparative example 4 were changed as follows.
Semiconductor substrate W; p + type (Resistivity: 0.01 to 0.02Ω · cm)

[Comparative Example 6]
In this comparative example 6, a semiconductor substrate W was manufactured by the same method as in the comparative example 4 except that the manufacturing conditions in the comparative example 4 were changed as follows.
Semiconductor substrate W: p-type (Resistivity: 6.06 to 24.8Ω · cm)
The manufacturing conditions of Examples 1 to 6 and Comparative Examples 1 to 6 are shown in Table 1.

And the semiconductor substrate W manufactured in the said Examples 1-6 and Comparative Examples 1-6 was evaluated with the following evaluation methods.
(Evaluation methods)
SFS6220 (made by KLA-Tencor, Gain 6) and SP1 (made by KLA-Tencor) for each semiconductor substrate W manufactured in Examples 1 to 6 and Comparative Examples 1 to 6 were evaluated for surface defects, foreign matter, and HAZE. ). Specifically, the SFS6220, SP1 optically detects surface defects, foreign matter, and HAZE of the semiconductor substrate W. The SFS6220, SP1 scans the entire surface of the semiconductor substrate W, and can detect the position of detected surface defects, foreign matter, and HAZE (in this evaluation, the portion where the roughness (HAZE) has deteriorated). Map display. In this evaluation, a predetermined number of semiconductor substrates W are manufactured in Examples 1 to 6 and Comparative Examples 1 to 6, respectively. And the ratio (stain occurrence rate) of the sheet | seat by which the spot was confirmed by the said test | inspection with respect to all manufactured was calculated.

  The evaluation results of Examples 1 to 6 and Comparative Examples 1 to 6 are shown in Table 2 above. Moreover, in Examples 1-6 and Comparative Examples 1-6, the example which displayed the map of the semiconductor substrate W surface in SP1 is shown in FIG. Specifically, FIG. 4A shows the evaluation result of the semiconductor substrate W in which no stain was confirmed, and FIGS. 4B and 4C show the evaluation results of the semiconductor substrate W in which the stain was confirmed. . 4A and 4B are HAZE MAP evaluated at SP1, and FIG. 4C is an LPD MAP evaluated at SP1.

As a result, spots as shown in FIG. 4B were confirmed in Comparative Examples 1 and 2, and spots as shown in FIG. 4C were confirmed in Comparative Examples 4 to 6. In addition, as shown in Table 2, Comparative Examples 1 to 6 resulted in a high spot generation rate.
In Comparative Examples 1 to 6, after the semiconductor substrate W was cleaned in the HF processing step, the semiconductor substrate W was cleaned with ozone water in the ozone processing step, and thus remained on the surface of the semiconductor substrate W. It is considered that the HF aqueous solution and ozone in the ozone water reacted to form unevenness (stain H1) of the roughness shown in FIGS. 4B and 4C on the surface of the semiconductor substrate W.

On the other hand, in Examples 1 to 6, as shown in Table 2, in the surface defect / foreign particle / HAZE evaluation, the spot generation rate was 0%. And in Examples 1-6, as shown to FIG. 4 (A), the favorable semiconductor substrate W without a stain was manufactured.
That is, when the comparative examples 1, 2, 4 to 6 and the examples 1, 2, 4 to 6 are compared, the pure water treatment process is performed after the HF treatment process, whereby the surface of the semiconductor substrate W is It is considered that the residue of the HF aqueous solution was removed, and as a result, it was possible to avoid the occurrence of a stain on the surface of the semiconductor substrate W without the reaction of the residue of the HF aqueous solution and the ozone in the ozone water in the ozone treatment step. It is done.

By the way, in Comparative Example 3, as shown in Table 2, in the surface defect / foreign particle / HAZE evaluation, a stain generation rate is 5% or less, and a good semiconductor substrate having no stain as shown in FIG. Many Ws were manufactured. The amount of unsaturated bonds (dangling bonds) on the substrate surface tends to differ depending on the resistivity of the semiconductor substrate W. The above result is considered to be caused by the difference in resistivity of the semiconductor substrate W.
For example, when the resistivity of the semiconductor substrate W is large (the resistivity exceeds 1 Ω · cm), the amount of unsaturated bonds on the substrate surface decreases. When such a semiconductor substrate W is washed with an HF aqueous solution, the residue of the HF aqueous solution captured by the unsaturated bond on the surface of the semiconductor substrate W is relatively small. For this reason, in Comparative Example 3 and Example 3, it is considered that the occurrence of spots was suppressed.
Therefore, it was confirmed that the cleaning treatment of the present invention is particularly effective for cleaning p ++, p + type semiconductor substrate W having a resistivity of 1 Ω · cm or less.

  Since the semiconductor substrate cleaning method of the present invention can improve the cleanliness of the surface of the semiconductor substrate and avoid the occurrence of uneven roughness on the surface of the semiconductor substrate, an HF processing step of cleaning the semiconductor substrate with an HF aqueous solution; This is useful for a semiconductor substrate cleaning method including an ozone treatment step of washing a semiconductor substrate with ozone water in which ozone is contained in pure water after the HF treatment step.

The figure which shows typically schematic structure of the cleaning apparatus of the semiconductor substrate in 1st Embodiment. Sectional drawing which shows typically the holding | maintenance state of the semiconductor substrate by the carrier in the said embodiment. The flowchart for demonstrating the manufacturing method of the semiconductor substrate in the said embodiment. The figure which shows an example which displayed the semiconductor substrate W surface as a map by the surface defect, foreign material, and HAZE evaluation in the said Example.

Explanation of symbols

W ... Semiconductor substrate S1 ... Mirror finish processing step S22 ... Ozone pretreatment step S23 ... HF treatment step S24 ... Pure water treatment step S25 ... Ozone treatment step

Claims (4)

Cleaning of a semiconductor substrate comprising: an HF treatment step for washing a semiconductor substrate with an HF aqueous solution; and an ozone treatment step for washing the semiconductor substrate with ozone water containing ozone in pure water after the HF treatment step. A method,
A method for cleaning a semiconductor substrate, comprising a pure water treatment step for washing the semiconductor substrate with pure water between the HF treatment step and the ozone treatment step. The method for cleaning a semiconductor substrate according to claim 1,
A method of cleaning a semiconductor substrate, wherein the semiconductor substrate is made of a material having a resistivity of 1 Ω · cm or less. In the cleaning method of the semiconductor substrate according to claim 1 or 2,
A method for cleaning a semiconductor substrate, comprising: an ozone pretreatment step for washing the semiconductor substrate with the ozone water before the HF treatment step.   4. A mirror surface processing step for mirror processing a semiconductor substrate, and a vapor phase growth processing step for vapor-phase epitaxial film growth on the surface of the semiconductor substrate or the mirror surface processing step. A method for manufacturing a semiconductor substrate, comprising performing the semiconductor substrate cleaning method described above.

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