WO2006035865A1

WO2006035865A1 - Semiconductor wafer manufacturing method and semiconductor wafer

Info

Publication number: WO2006035865A1
Application number: PCT/JP2005/017936
Authority: WO
Inventors: Hideki Munakata
Original assignee: Shin-Etsu Handotai Co., Ltd.
Priority date: 2004-09-30
Filing date: 2005-09-29
Publication date: 2006-04-06
Also published as: JPWO2006035865A1; JP4683233B2

Abstract

A semiconductor wafer manufacturing method is at least provided with a primary polishing process of roughly polishing a material wafer, a finishing polishing process wherein finishing polishing is performed to the wafer polished by the primary polishing, and a cleaning process for cleaning the wafer to which the finishing polishing is performed. In the cleaning process, chemical cleaning is performed by having an etching margin of 0.2-1.0nm. Thus, the semiconductor wafer manufacturing method and a semiconductor wafer are provided for improving a haze level to an extent that a particle which is adhered on a wafer surface and has a size of, for instance, 47nm or more can be surely measured.

Description

Semiconductor wafer manufacturing method and semiconductor wafer

Technical field

The present invention relates to a method for manufacturing a semiconductor wafer having an improved haze level, and more particularly to a cleaning process thereof. Background art

[0002] In the manufacture of conventional semiconductor silicon wafers, a slicing process in which a silicon single crystal rod manufactured by a single crystal manufacturing apparatus is sliced to obtain a thin disc-shaped woofer, and a wafer obtained in the slicing process is obtained. Chamfering process for chamfering the outer edge to prevent cracking and chipping, wrapping process for lapping the chamfered wafer and flattening it, and chamfered and lapped wafer surface An etching process that removes the processing strain remaining on the surface, a primary polishing process in which the surface of the etched wafer is brought into sliding contact with a polishing cloth to perform rough polishing mainly for adjusting the flatness, and a primary polishing process. The final polishing process mainly aimed at improving the surface roughness (so-called haze) having a wavelength of several to several tens of nanometers on the surface of the wafer, and the final polished wafer is washed. A final cleaning step is performed to remove the abrasives and foreign matter that have been cleaned and attached to the wafer.

In addition, heat treatment and surface grinding processes are performed as necessary, and addition, omission, replacement, and repetition of processes are performed according to the purpose.

Here, the primary polishing process will be described in more detail. The primary polishing performed as rough polishing is polishing performed to increase the flatness of the wafer surface after the etching process or the surface grinding process, and the shape is corrected. Done to do. In general, the polishing cloth used for rough polishing is, for example, Asker C hardness (a type of spring hardness tester C-type, a type of spring hardness tester) in which polyester felt (with a random structure) is impregnated with polyurethane. A relatively hard material with a value of 80) is used. A polishing cloth is affixed on a rotatable surface plate, an abrasive containing colloidal silica is used in an alkali-based aqueous solution, and the wafer is rubbed against the polishing cloth while supplying the abrasive between the wafer and the polishing cloth. Yo Polishing is performed. Under the conditions used in such rough polishing such as primary polishing, the polishing cloth is hard, so a minute scratch on the wafer surface called scratch may occur.

[0004] On the other hand, final polishing is the final process of wafer polishing, with the aim of reducing the unevenness of several to several tens of nanometer levels called haze to obtain a mirror surface and removing scratches generated by rough polishing. Process. For finishing polishing, a suede-like artificial leather made of soft foamed urethane is pasted on a rotatable surface plate, and the wafer is rubbed while supplying an abrasive containing colloidal silica to an alkali-based aqueous solution. This is done by

Here, FIG. 2 shows a polishing apparatus used for finish polishing. In FIG. 2, the polishing apparatus comprises a rotating platen 2, a wafer holder 3, and an abrasive supply device 5. The rotating surface plate 2 has a rotating surface plate body, and a polishing cloth 4 is pasted on the upper surface thereof. The rotating surface plate 2 is rotated at a predetermined rotational speed by a rotating shaft. The wafer holder 3 holds the wafer 1 on the lower surface thereof by vacuum suction or the like and is rotated by the rotating shaft and simultaneously presses the wafer 1 against the polishing cloth 4 with a predetermined load. The abrasive supply device 5 supplies an abrasive onto the polishing cloth at a predetermined flow rate from an abrasive supply tank (not shown), and the abrasive 1 is supplied between the wafer 1 and the polishing cloth 4 so that the wafer 1 Is polished.

[0006] Since the polishing cloth used for finish polishing is generally softer than the polishing cloth used for rough polishing, scratches are unlikely to occur. However, if the polishing pressure is increased, scratches are likely to occur. Finish polishing is generally performed at a relatively low polishing pressure.

[0007] Next, the cleaning process will be described. A cleaning process such as RCA cleaning, which has a combined force of removing foreign substances on the surface with chemicals and rinsing with pure water, is often used.

[0008] A typical process procedure of the powerful RC A cleaning process is shown below.

1) SC-1 cleaning (Ammonia: Hydrogen peroxide solution: Water = 1: 1: 5-7)

2) Pure water rinse

3) Hydrofluoric acid cleaning

4) Pure water rinse

5) SC-2 cleaning (hydrochloric acid: hydrogen peroxide water: water = 1: 1 to 2: 6 to 8) 6) Pure water rinse

7) Spin dry

The pure water rinsing process may be repeated a plurality of times.

In addition, cleaning without using a chemical solution has been performed, and cleaning methods using brush cleaning and a two-fluid nozzle have also been proposed (see, for example, JP-A-2003-22993).

[0009] In recent years, with the progress of high integration of semiconductor devices, the minimum line width of the circuit itself has become a level of 0.13 m or less, and the size of the problem of particles adhering to the wafer surface has also reached a level of 47 nm or more. Come on.

On the other hand, a surface roughness having a wavelength of several to several tens of nm called haze remains on the surface of the semiconductor silicon wafer manufactured by the above manufacturing method even after finishing polishing and cleaning. If haze remains on the wafer surface in this way, the particle counter that measures the number of particles will recognize the haze as particles. This tendency increases as the particle size to be measured decreases. For example, when trying to measure the number of particles with a size of 47 nm or more on a wafer surface manufactured by a conventional method, it was difficult to measure the actual number of particles due to the effect of haze. Disclosure of the invention

[0011] The present invention has been made in view of such problems, and a semiconductor wafer having an improved haze level to such an extent that particles having a size of 47 nm or more attached to the wafer surface can be reliably measured, for example. It is an object of the present invention to provide a manufacturing method and a semiconductor wafer.

[0012] The present invention has been made to solve the above problems, and is a method for manufacturing a semiconductor wafer, comprising at least a primary polishing step of roughly polishing a raw material wafer, and the primary polished wafer. And a final polishing process for final polishing, and a cleaning process for cleaning the final polished wafer, in which chemical cleaning is performed with an etching allowance of 0.2 to 1. Onm. A method for manufacturing a semiconductor wafer is provided.

[0013] In the cleaning process for cleaning the wafer after the finish polishing process as described above, the chemical haze level of the wafer is deteriorated by performing chemical cleaning with an etching allowance of 0.2 to 1. Onm. This makes it possible to manufacture a semiconductor wafer that can reliably measure a 47-nm or larger size particle adhering to the wafer surface.

[0014] In this case, in the cleaning step, it is preferable to perform chemical cleaning with an etching allowance of 0.2 to 1. Onm after performing mechanical cleaning by applying a mechanical force.

[0015] After performing mechanical cleaning in this manner, chemical cleaning with an etching allowance of 0.2 to 1. Onm can be performed to reduce particles on the wafer surface.

[0016] In the cleaning step, it is preferable to perform chemical cleaning with an etching allowance of 0.2 to 1. Onm simultaneously with mechanical cleaning.

[0017] By performing chemical cleaning with an etching allowance of 0.2 to 1. Onm simultaneously with mechanical cleaning, particles on the wafer surface can be further reduced.

[0018] Further, in the cleaning step, the first chemical cleaning is performed simultaneously with the mechanical cleaning, and then the second chemical cleaning is further performed to perform the total etching by the first and second chemical cleaning. The bill can be 0.2 to 1. Onm.

[0019] Thus, the first chemical cleaning is performed simultaneously with the mechanical cleaning, and then the second chemical cleaning is further performed, so that the total etching allowance by the first and second chemical cleaning is 0.2 to 1. Good as Onm.

[0020] Further, in the cleaning step, it is preferable to perform chemical cleaning with an etching allowance of 0.2 to 1. Onm after performing mechanical cleaning following ozone cleaning for cleaning the wafer with ozone water. .

[0021] In this way, after performing mechanical cleaning following ozone cleaning, chemical cleaning with an etching allowance of 0.2 to 1. Onm is performed, so that organic substances attached to the wafer can be easily peeled off. be able to.

[0022] In the cleaning step, chemical cleaning with an etching allowance of 0.2 to 1. Onm can be performed simultaneously with mechanical cleaning, following ozone cleaning.

[0023] As described above, by performing chemical cleaning with an etching margin of 0.2 to 1.0 nm simultaneously with mechanical cleaning, following ozone cleaning, particles on the wafer surface can be further reduced. Can do.

[0024] Further, in the cleaning step, following the ozone cleaning, mechanical cleaning and first chemical cleaning are performed. The total etching allowance for the first and second chemical cleaning can be reduced to 0.2 to 1. Onm.

[0025] As described above, the ozone cleaning is followed by the mechanical cleaning and the first chemical cleaning at the same time, and then the second chemical cleaning is performed and the total etching by the first and second chemical cleaning is performed. The ringing cost may be 0.2 to 1. Onm.

[0026] Further, it is preferable that the chemical cleaning is cleaning with a mixed aqueous solution of ammonia water, peroxy hydrogen water and water!

[0027] As described above, the chemical cleaning is performed by cleaning with a mixed aqueous solution of ammonia water, peroxyhydrogen water, and water, so that the desired etching allowance can be ensured, and the wafer surface can be further improved. Particles can be reduced.

[0028] The mechanical cleaning is preferably two-fluid cleaning in which two or more kinds of fluids are mixed to clean the wafer.

[0029] In this way, by using two-fluid cleaning as the mechanical cleaning, it is possible to further reduce the wafer surface partition.

[0030] The temperature of the ozone water in the ozone cleaning is preferably 50 ° C or higher.

[0031] Thus, by setting the temperature of the ozone water in the ozone cleaning to 50 ° C or higher, the cleaning power can be improved, and particles on the surface of the organic substance can be further reduced.

[0032] Further, the present invention provides a mirror-polished semiconductor wafer having a haze of 5 ppb or less,

Provided is a semiconductor wafer characterized in that particles having a size of 47 nm or more are 0.15 particles / cm ² or less.

[0033] Such a semiconductor wafer is an unprecedented high quality semiconductor wafer with less haze and minute particles.

As described above, according to the present invention, it is possible to manufacture a semiconductor wafer having an improved haze level to such an extent that particles having a size of, for example, 47 ηm or more adhering to the surface of the semiconductor wafer can be reliably measured.

Brief Description of Drawings FIG. 1 is a flowchart schematically illustrating an example of a method for producing a semiconductor wafer according to the present invention.

FIG. 2 is an example of a finish polishing apparatus used in a semiconductor wafer manufacturing method.

FIG. 3 is an example of a cleaning apparatus that can be used in the method for manufacturing a semiconductor wafer of the present invention.

[FIG. 4] (a) is a flow diagram schematically illustrating an example of the method of manufacturing a semiconductor wafer of the present invention, and (b) is another example of the method of manufacturing the semiconductor wafer of the present invention. It is a flowchart explaining roughly. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the power to explain the present invention in more detail The present invention is not limited to these.

On the surface of a semiconductor silicon wafer manufactured by a conventional manufacturing method, a surface roughness having a wavelength of several to several tens of nm called haze remained even after finishing polishing and cleaning. Since the particle counter recognizes this haze as a particle, for example, even if it was attempted to measure the number of particles with a size of 47 nm or more, which has been required in recent years, it was not possible to make a reliable measurement. This is because conventional RCA cleaning is performed after finishing polishing, and wafers are etched with a machining allowance of about 4 nm or more, and the haze level remaining in finishing polishing is further deteriorated to about 30 ppb or more. It turned out to be. Therefore, as a result of repeated investigations, the inventors have been able to minimize the deterioration of the haze level of wafers by setting the etching cost in the cleaning process to 0.2 to 1. Onm smaller than before. The present inventors have found that the number of particles adhering to the wafer surface can be measured.

[0037] A method for manufacturing a semiconductor wafer according to the present invention will be described below with reference to FIG. 1 as an example of the case of manufacturing a silicon wafer.

[0038] First, a silicon single crystal ingot pulled up by a single crystal pulling apparatus (not shown) is sliced at a right angle or at an angle with respect to the rod axis direction to obtain a plurality of thin disk-shaped wafers (slices). Process). The wafer obtained by the above slicing process is chamfered at its outer edge in order to prevent cracking (chamfering process). Next, Sly In addition to removing the work-affected layer induced on the wafer surface by cutting in the wafer process, the wafer is mechanically ground (lapped) to flatten the wafer (lapping process). Further, the wafer is etched (etching process) in order to remove the processing distortion generated in the wafer surface layer in the above process.

[0039] Subsequently, in order to further flatten the surface of the etched wafer, rough polishing is performed (primary polishing step). This rough polishing (primary polishing) may be composed of two stages or three or more stages. For example, it is possible to polish using a coarse abrasive at the first stage and a finer abrasive after the second stage.

Furthermore, the surface of the wafer is polished using a polishing apparatus as shown in FIG. 2 to obtain a mirror surface with a level of unevenness called haze, and scratches generated in the primary polishing are removed (finish polishing step). .

[0040] The semiconductor silicon wafer that has been subjected to final polishing is cleaned to remove the abrasive and the like (cleaning step). In the cleaning process after finish polishing, the present invention prevents the haze level from deteriorating by performing chemical cleaning with an etching margin of 0.2 to 1. Onm, and particles having a size of 47 nm or more on the wafer surface. It is characterized in that it can be measured. In this case, the number of particles can be further reduced by performing mechanical cleaning before chemical cleaning. When combined with ozone cleaning, it is also effective in removing organic substances, and a higher quality semiconductor wafer can be obtained. Hereinafter, the cleaning process performed in the present invention will be described in detail by taking as an example the case of performing ozone cleaning, mechanical cleaning, and chemical cleaning in this order.

FIG. 3 shows an example of a cleaning apparatus used in the cleaning process.

First, ozone cleaning is performed. In ozone cleaning, for example, 5 to: pure water 8 containing LOOppm of ozone is sprayed from nozzle 10 toward rotating wafer 1. At this time, the nozzle 10 is scanned in the radial direction of the wafer. By performing ozone cleaning in this way, contaminants such as organic matter adhering to the wafer surface can be effectively removed. At this time, if the temperature of the ozone water is set to 50 ° C or more, it is preferable because the cleaning power is improved and more contaminants can be removed.

[0042] Next, mechanical cleaning is performed. Mechanical cleaning is the application of mechanical and physical forces to the wafer surface. This refers to removal by applying to attached impurities (particles, etc.), for example, brush cleaning or two-fluid cleaning. In this two-fluid cleaning, two or more fluids are mixed and the mixed fluid is sprayed onto the wafer surface to remove impurities. For example, ultrapure water 7 to which carbon dioxide (CO) is added and nitrogen gas (N) 6 are mixed with a two-fluid cleaning nozzle 9.

twenty two

Then, the nozzle is scanned in the radial direction of the woofer and sprayed on the surface of the rotating woofer 1. If ultrapure water to which carbon dioxide is added is used as a cleaning liquid in this way, static electricity generated by friction between the processing surface of the semiconductor wafer and the cleaning liquid can be suppressed. In addition, as a gas used as a gas, a suitable force is nitrogen (N), which is an inert gas.

2

In addition, air, argon (Ar), or the like can be used.

Next, chemical cleaning is performed. Chemical cleaning refers to the process of chemically dissolving and decomposing and removing metal particles, etc. that adhere to the wafer surface and that are organic, organic, and abrasive.

Here, as an example of chemical cleaning, cleaning is performed using a mixed aqueous solution of low-concentration aqueous ammonia, peroxyhydrogen water, and water.

As for the cleaning solution, the normal SC-1 cleaning used in RCA cleaning uses an ammonia water: peroxy acid-basic water: water: water composition ratio of 1: 1: 5, whereas 1: 1: Use 10-200.

By immersing the wafer in a cleaning solution tank filled with this cleaning solution, cleaning is performed using a mixed solution of low-concentration ammonia water, hydrogen peroxide solution, and water. At this time, the cleaning time is adjusted so that the etching allowance is 0.2 to 1.0 nm. If the etching allowance is less than 0.2 nm, the polishing agent cannot be completely removed, resulting in poor particle levels. In addition, if the etching allowance is made larger than 1. Onm, the haze level becomes poor and the measurement of particles is hindered. Therefore, chemical cleaning is performed with an etching allowance of 0.2 to 1. Onm in this way, and the haze level of the wafer is improved, and the number of particles having a size of, for example, 47 nm or more attached to the wafer surface can be reliably measured. Like that.

As another example of chemical cleaning, chemical cleaning is performed using an alkaline solution such as diluted KOH (for example, 0.1 wt% to 10 wt%) or diluted NaOH (for example, 0.1 wt% to 10 wt%). Chisaru [0044] Finally, the woofer is dried. The drying method is not particularly limited. For example, the wafer is placed on a mounting table on which a groove having a hollow portion and an opening is formed, and the water adhering to the surface of the wafer is reduced by reducing the pressure of the hollow portion. It is possible to perform so-called suction drying or spin drying in which water is sprinkled off from the oven using centrifugal force. A semiconductor silicon wafer is obtained as described above.

[0045] In the cleaning step, mechanical cleaning and chemical cleaning have been described separately. However, mechanical cleaning and chemical cleaning may be performed simultaneously. For example, as shown in FIG. 4 (a), chemical cleaning with an etching allowance of 0.2 to 1. Onm may be performed simultaneously with mechanical cleaning, following ozone cleaning. Alternatively, as shown in FIG. 4 (b), after the ozone cleaning, the mechanical cleaning and the first chemical cleaning are performed at the same time, and then the second chemical cleaning is further performed. The total etching allowance by chemical cleaning may be 0.2 to 1. Onm.

[0046] When performing mechanical cleaning and chemical cleaning at the same time, for example, in the above-mentioned two-fluid cleaning! /, Instead of ultra pure water, a mixed aqueous solution of ammonia water, hydrogen peroxide water and water is used. For this reason, gas can be mixed with this and mechanical cleaning can be performed simultaneously with chemical cleaning with etching.

[0047] Even when these mechanical cleaning and chemical cleaning are performed simultaneously, combining ozone cleaning as shown in Fig. 4 (a) and Fig. 4 (b) is effective in removing organic matter. Thus, a higher quality semiconductor wafer can be obtained. However, it is quite possible to omit this ozone cleaning.

[0048] The semiconductor wafer obtained by the above method has a haze of 5 ppb or less and a particle size of 47 nm or more of 0.15 particles / cm ² or less (100 mm / 300 mm diameter wafer). It can be a high quality semiconductor wafer with less particles.

[0049] Examples of the present invention will be described below, but the present invention is not limited thereto.

(Example 1)

A single crystal with a diameter of 300 mm and an orientation of {100} is pulled up by the Chiyoklarsky method, Rice was chamfered and lapped to prepare silicon wafers.

This silicon wafer was etched by a conventional method to obtain an etch wafer.

[0050] Next, while supplying a polishing liquid containing a colloidal silica-based abrasive to the polishing cloth of the polishing apparatus

Then, the polishing cloth was subjected to primary polishing by sliding the etch dowel.

In addition, a suede-like artificial leather made of soft foamed urethane is affixed to a rotatable surface plate, and the wafer is slid in contact with an abrasive solution containing colloidal silica in an alkali-based aqueous solution. And finish polished.

[0051] Next, the cleaning process was performed in the order of ozone cleaning, two-fluid cleaning, and chemical cleaning. The cleaning equipment shown in Fig. 3 was used for ozone cleaning and two-fluid cleaning.

First, in ozone cleaning, normal water containing ozone at 20 ppm from nozzle 10 is flowed 1.

At 2L / min, spray was directed to wafer 1 rotating at 60rpm. At this time, the distance between nozzle 10 and wafer 1 was 30 mm, and the angle of nozzle 10 was 75 °. Nozzle 10 was scanned so that one round trip in the radial direction of the wafer was 30 seconds.

[0052] In the subsequent two-fluid cleaning, 0.2 L / min'0.5MP of ultrapure water to which carbon dioxide (CO 2) has been added is used.

2

In a, nitrogen (N) was supplied to the nozzle 9 at 235 L / mim'0.4 MPa and mixed, and the mixture was mixed.

2

The fluid was sprayed toward wafer 1 rotating at 1800 rpm. At this time, the distance between nozzle 9 and ueno 1 was 20 mm, and the angle of nozzle 9 was 90 °. In addition, nozzle 9 was scanned in the radial direction of wafer so that one reciprocation was 30 seconds.

[0053] In the next chemical cleaning, the composition ratio of ammonia water: hydrogen peroxide water: water is 1: 1: 1 in the water purification tank.

This was done by filling a cleaning solution of 100 and immersing the wafer in this. At this time, the etching allowance was adjusted to 0.2 nm.

Subsequently, the wafer was dried by spin drying to obtain a semiconductor wafer.

[0054] (Example 2)

A silicon wafer obtained by slicing the same silicon single crystal as in Example 1 was chamfered, rubbed, etched, and subjected to primary polishing and final polishing. Further, for this wafer, cleaning steps were performed in the order of ozone cleaning, two-fluid cleaning, and chemical cleaning under the same conditions as in Example 1 except that the etching allowance for chemical cleaning was 0.5 nm. Next, dry the woofer Line, got a semiconductor wafer.

[Example 3]

A silicon wafer obtained by slicing the same silicon single crystal as in Example 1 was chamfered, lapped, etched, and subjected to primary polishing and final polishing. Further, for this wafer, cleaning steps were performed in the order of ozone cleaning, two-fluid cleaning, and chemical cleaning under the same conditions as in Example 1 except that the etching cost for chemical cleaning was set to 1. Onm. . Subsequently, the wafer was dried to obtain a semiconductor wafer.

[0056] (Example 4)

A silicon wafer obtained by slicing the same silicon single crystal as in Example 1 was chamfered, rubbed, etched, and subjected to primary polishing and final polishing. Further, for this wafer, cleaning steps were performed in the order of ozone cleaning, two-fluid cleaning and chemical cleaning under the same conditions as in Example 1 except that the temperature of ozone water for ozone cleaning was 40 ° C. Subsequently, the wafer was dried to obtain a semiconductor wafer.

[0057] (Example 5)

A silicon wafer obtained by slicing the same silicon single crystal as in Example 1 was chamfered, rubbed, etched, and subjected to primary polishing and final polishing. Further, for this wafer, cleaning steps were performed in the order of ozone cleaning, two-fluid cleaning and chemical cleaning under the same conditions as in Example 1 except that the temperature of ozone water for ozone cleaning was 50 ° C. Subsequently, the wafer was dried to obtain a semiconductor wafer.

[Example 6]

A silicon wafer obtained by slicing the same silicon single crystal as in Example 1 was chamfered, rubbed, etched, and subjected to primary polishing and final polishing. Further, the wafer was only subjected to chemical cleaning under the same conditions as in Example 1 as a cleaning process. Subsequently, the wafer was dried! A semiconductor wafer was obtained. [Example 7]

A silicon wafer obtained by slicing the same silicon single crystal as in Example 1 was chamfered, rubbed, etched, and subjected to primary polishing and final polishing. The wafer was subjected to the same ozone cleaning as in Example 1, followed by a two-fluid cleaning. In this two-fluid cleaning, instead of the ultrapure water of Example 1, a cleaning solution having a thread ratio of 1: 1: 100 of ammonia water: hydrogen peroxide water: water is used, and chemical cleaning is performed simultaneously with mechanical cleaning. Washing was performed. At this time, the etching margin was adjusted to be 0.2 nm. Subsequently, the wafer was dried by spin drying to obtain a semiconductor wafer.

[0060] (Example 8)

A silicon wafer obtained by slicing the same silicon single crystal as in Example 1 was chamfered, rubbed, etched, and subjected to primary polishing and final polishing. The wafer was subjected to ozone cleaning under the same conditions as in Example 7 except that the etching cost for chemical cleaning was set to 1. Onm, followed by two-fluid cleaning (chemical cleaning simultaneously with mechanical cleaning). Subsequently, the wafer was dried by spin drying to obtain a semiconductor wafer.

[Example 9]

A silicon wafer obtained by slicing the same silicon single crystal as in Example 1 was chamfered, rubbed, etched, and subjected to primary polishing and final polishing. The wafer was subjected to the same ozone cleaning as in Example 1, followed by a two-fluid cleaning. In this two-fluid cleaning, instead of the ultrapure water of Example 1, a cleaning solution having a thread ratio of 1: 1: 100 of ammonia water: hydrogen peroxide water: water is used. One chemical wash was performed. Furthermore, the second chemical cleaning was performed by filling the water purification tank with a cleaning solution having a composition ratio of ammonia water: hydrogen peroxide water: water of 1: 1: 100 and immersing the wafer in the cleaning solution. . At this time, the total etching allowance of the first and second chemical cleaning was adjusted to be 0.2 nm. Subsequently, the wafer was dried by spin drying to obtain a semiconductor wafer. [Example 10]

A silicon wafer obtained by slicing the same silicon single crystal as in Example 1 was chamfered, rubbed, etched, and subjected to primary polishing and final polishing. For this wafer, ozone cleaning was performed under the same conditions as in Example 9 except that the total etching allowance for the first and second chemical cleaning was adjusted to 1. Onm, followed by two-fluid cleaning (mechanical cleaning). At the same time, a first chemical cleaning was performed, followed by a second chemical cleaning. Subsequently, the wafer was dried by spin drying to obtain a semiconductor wafer.

[0063] (Comparative Example 1)

A silicon wafer obtained by slicing the same silicon single crystal as in Example 1 was chamfered, rubbed, etched, and subjected to primary polishing and final polishing. In addition, a conventional RCA cleaning process was performed on the wafer. RCA cleaning was performed by immersing wafers in a cleaning solution tank filled with cleaning solution in the order SC-1 cleaning 'hydrofluoric acid cleaning' SC-2 cleaning. The mixing ratio of the cleaning solution used for SC-1 cleaning was ammonia: hydrogen peroxide-hydrogen water: water = 1: 1: 5, and the mixing ratio of the cleaning solution used for SC-2 cleaning was hydrochloric acid: peroxide. Hydrogen water: water = 1: 1: 6. The etching cost for SC-1 cleaning was adjusted to 4 nm.

Finally, the wafer was dried and a semiconductor wafer was obtained.

[0064] (Comparative Example 2)

A silicon wafer obtained by slicing the same silicon single crystal as in Example 1 was chamfered, rubbed, etched, and subjected to primary polishing and final polishing. Further, the wafer was subjected to a cleaning process in the order of ozone cleaning and two-fluid cleaning under the same conditions as in Example 1 without performing chemical cleaning. Subsequently, the woofer was dried to obtain a semiconductor woofer.

[0065] (Comparative Example 3)

A silicon wafer obtained by slicing the same silicon single crystal as in Example 1 was chamfered, rubbed, etched, and subjected to primary polishing and final polishing. Furthermore, for this wafer, ozone was removed under the same conditions as in Example 1 except that the etching allowance for chemical cleaning was 1.5 nm. Cleaning · The cleaning process was performed in the order of two-fluid cleaning and chemical cleaning. Subsequently, the wafer was dried to obtain a semiconductor wafer.

[0066] (Evaluation method)

The haze level and the number of particles of the semiconductor wafer obtained in the above examples and comparative examples were measured in the DWO mode of a surface inspection apparatus (trade name: SP1) manufactured by KLA TENCOR. The results obtained are shown in Table 1.

[table 1]

[0067] When the results of Examples 1 to 10 and Comparative Example 1 are compared, the wafers manufactured using the cleaning process according to the present invention have a greater haze than the wafers manufactured using conventional RCA cleaning. It has been improved. Therefore, it was confirmed that the method of the present invention was effective in improving the haze of the wafer and measuring the number of fine particles adhering to the wafer surface.

[0068] Further, when comparing Examples 1 to 3 with Comparative Examples 1 and 3, compared with Examples 1 to 3 where the etching allowance in chemical cleaning was 0.2 to 1. Onm, 4 nm and 1. The haze level of Comparative Examples 1 and 3 with 5 nm is very bad. Therefore, it was confirmed that limiting the etching allowance to 0.2 to 1. Onm has a high effect on improving the haze level of wafers. In addition, comparing Example 4 and Example 5, in Example 5 where the temperature of ozone water for ozone cleaning was 50 ° C or higher, the number of particles was considerably improved, and the temperature of ozone water was 50 ° C or higher. As a result, it was confirmed that ozone cleaning and two-fluid cleaning contributed to the reduction of the particle by comparing Example 1 and Example 6. .

Further, when Example 1 was compared with Examples 7 and 9, it was confirmed that particles were reduced by performing chemical cleaning simultaneously with mechanical cleaning.

Similarly, when Example 3 was compared with Examples 8 and 10, it was confirmed that particles were reduced by performing chemical cleaning simultaneously with mechanical cleaning.

In addition, as in Comparative Example 2, particles cannot be removed without chemical cleaning.

The present invention is not limited to the above embodiment. The above embodiment is an exemplification, and the present invention has the same configuration as the technical idea described in the scope of claims of the present invention, and any device that exhibits the same function and effect is the present embodiment. It is included in the technical scope of the invention.

For example, the semiconductor wafer to which the present invention can be applied is not limited to a silicon wafer, but can also be applied to a wafer such as a compound semiconductor.

Claims

The scope of the claims

[1] A method for manufacturing a semiconductor wafer, comprising at least a primary polishing step for roughly polishing a raw wafer, a final polishing step for final polishing the primary polished wafer, and the finish polishing. And a cleaning process for cleaning the wafer, and performing a chemical cleaning with an etching allowance of 0.2 to 1. Onm through the cleaning process.

[2] In the cleaning step, after performing mechanical cleaning by applying mechanical force!], Chemical cleaning is performed with an etching allowance of 0.2 to 1. Onm. The method for producing a semiconductor wafer according to claim 1.

[3] The method for producing a semiconductor wafer according to [1], wherein in the cleaning step, chemical cleaning is performed with an etching allowance of 0.2 to 1. Onm simultaneously with mechanical cleaning.

[4] In the cleaning step, the first chemical cleaning is performed simultaneously with the mechanical cleaning, and then the second chemical cleaning is further performed to reduce the total etching allowance by the first and second chemical cleanings. 2. The method for producing a semiconductor wafer according to claim 1, wherein the thickness is set to 2 to 1. Onm.

[5] The cleaning step is characterized by performing chemical cleaning with an etching allowance of 0.2 to 1. Onm after performing mechanical cleaning following ozone cleaning for cleaning wafers with ozone water. The method for producing a semiconductor wafer according to claim 1.

[6] The chemical cleaning according to claim 1, wherein the cleaning step is followed by ozone cleaning, followed by mechanical cleaning and chemical cleaning with an etching allowance of 0.2 to 1. Onm. A method for producing a semiconductor wafer according to 1.

[7] In the cleaning step, following the ozone cleaning, the mechanical cleaning and the first chemical cleaning are simultaneously performed, and then the second chemical cleaning is further performed to obtain the first and second chemical cleaning. 2. The method for producing a semiconductor wafer according to claim 1, wherein the total etching allowance is set to 0.2 to 1. Onm.

[8] The semiconductor queue according to any one of [1] to [7], wherein the chemical cleaning is cleaning with a mixed aqueous solution of ammonia water, peroxyhydrogen water, and water. Method for manufacturing c.

[9] The semiconductor wafer according to any one of [2] to [8], wherein the mechanical cleaning is a two-fluid cleaning in which two or more kinds of fluids are mixed to clean the wafer. Manufacturing method.

10. The method for producing a semiconductor wafer according to any one of claims 5 to 9, wherein the temperature of the ozone water in the ozone cleaning is set to 50 ° C or higher. A mirror-polished semiconductor wafer having a haze of 5 ppb or less and a particle size of 47 nm or more of 0.15 particles / cm ² or less.