JP2005051099A - Method of cleaning substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate cleaning technique for improving the rinse effect carried out after chemical processing so as to reduce the consumption of the rinsing DIW. <P>SOLUTION: A rinsing process with a weak alkaline solution is provided after an APM treating process is carried out, so that an electrostatic force acting between the surface of a substrate and particles can be made minus by controlling, and the particles are prevented from sticking again to the surface of the substrate. By this setup, a rinsing process performed after an APM treatment can be carried out in a shorter time than usual, so that the DIW can be reduced in consumption. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a substrate cleaning method, and more particularly to a cleaning technique for cleaning a thin plate substrate such as a semiconductor substrate or a liquid crystal glass substrate using a cleaning liquid.

As this type of substrate cleaning method, for example, a conventional semiconductor substrate cleaning method, an RCA cleaning method is known. If an example of this RCA cleaning method is given, the process steps as shown in FIG. 6 are followed (for example, see Non-Patent Document 1).

In particular,
First, the substrate is treated with APM (ammonia hydrogen peroxide) a and then rinsed with DIW (ultra pure water) b.
Next, the substrate is treated with HPM (hydrochloric acid excess water) c and then rinsed with DIWd.
Further, the substrate is treated with DHF (dilute hydrofluoric acid) e and then rinsed with DIWf.
Finally, the substrate is dried with a dryer g such as an IPA dryer or a spin dryer.

The above APM treatment removes particles adhering to the substrate surface by oxidizing the substrate (silicon) surface with hydrogen peroxide solution, lifting off the oxide film with ammonia, and then performing a substitution rinse with DIW. In this case, once lifted off particles may be reattached to the substrate surface, and a large amount of DIW is required for rinsing so as not to leave the particles and the APM treatment liquid.

However, even when rinsing with a large amount of DIW in this way, particles may remain on the substrate surface after APM treatment.

In addition, when a large amount of DIW is consumed, not only the running cost increases, but also affects environmental problems.
Ricoh Technical Report No.22, JULY, 1996

An object of the present invention is to prevent reattachment of particles lifted off from the substrate surface in the rinsing process immediately after the APM process, thereby accelerating the rinsing process and suppressing consumption of DIW.

  In order to achieve this object, a substrate cleaning method of the present invention is a substrate cleaning method of cleaning a substrate by sequentially using a plurality of cleaning liquids according to a cleaning recipe, and is an APM process for processing a substrate by at least APM. Comprising a step of rinsing with a weak alkaline solution after the APM treatment step.

  In a preferred embodiment, ammonia water, hydrogen water, or a mixed solution of ammonia water and hydrogen water is used as the weak alkaline solution.

  According to the present invention, since the weakly alkaline solution ammonia water, hydrogen water, or a mixed solution of these ammonia water and hydrogen water is used for the rinse liquid immediately after cleaning with APM, The electrostatic force acting between the particles is controlled to the minus side to prevent the particles from reattaching to the substrate surface. As a result, the rinsing process after the APM treatment can be accelerated compared to the conventional cleaning method, and consumption of DIW can be suppressed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1
The processing steps of the substrate cleaning method according to the present invention are shown in FIG.

-The substrate surface is treated with APM (ammonia peroxide) by dipping or spraying (processing step 1). As conventionally known, this APM treatment is a process in which particles on the substrate surface are lifted off together with the oxide film by oxidizing the substrate surface with hydrogen peroxide water and removing the oxide film with ammonia.

Ammonia water (cleaning solution in which NH ₄ OH is dissolved in pure water) (processing step 2a) or hydrogen water (cleaning solution in which H ₂ is dissolved in pure water) (processing step 2b), or ammonia water and hydrogen, which are weak alkaline solutions Rinse with a cleaning solution mixed with water (treatment step 2c).

  Before the rinsing step with DIW (ultra pure water), the substrate surface of particles lifted off is controlled by negatively controlling the electrostatic force acting between the substrate surface and the particles by rinsing with the weak alkaline solution as described above. Reattachment to is prevented.

  The concentration of ammonia water, hydrogen water, or a mixed solution of ammonia water and hydrogen water used above is several P.P.M, preferably 2 P.P.M or less.

-Rinse with DIW (process step 3). The amount of DIW used at this time can be greatly reduced by the above-described measures for preventing reattachment of particles as compared with the conventional method.

-Treat with HPM (hydrochloric acid overwater) (treatment step 4). In this HPM treatment, as conventionally known, heavy metals (Fe, Ni, Cr, Cu, etc.) adhering to the substrate surface are dissolved and removed with HCL (hydrochloric acid).

5) Rinse with DIW (process step 5).

6) Treat with DHF (dilute hydrofluoric acid) (process step 6). The DHF process is the same as a conventionally employed method, and the natural oxide film on the substrate surface is removed.

-Rinse with DIW (process step 7). This rinse becomes the final rinse of the main cleaning step.

-The substrate is later dried with a dryer such as an IPA dryer or a spin dryer (processing step 8).

  The above-described cleaning process is repeatedly performed along the cleaning recipe.

Embodiment 2.
This embodiment is shown in FIG. 2, and the cleaning method of Embodiment 1 is applied to a multi-bus type cleaning apparatus.

  This multi-bus type substrate cleaning section includes a cleaning tank array in which a plurality of (in the illustrated case, four) single-function cleaning tanks A to D that can be cleaned with a dedicated processing liquid (cleaning liquid) are arranged. The substrate transferred from the carrier cassette for transfer in the substrate carry-in unit E to the substrate transfer processing robot in the substrate transfer unit F is sequentially immersed in each of the single-function cleaning tanks A to D for cleaning by the substrate transfer robot. It is processed.

In particular,
1) After the substrate is treated with the first treatment liquid APM in the first washing tank A, the substrate is rinsed with ammonia water or hydrogen water, or a mixed liquid of ammonia water and hydrogen water in the same washing tank A. Further, in the cleaning tank A, rinsing is performed with DIW.

2) After being treated with the second treatment liquid HPM in the second washing tank B, the same washing tank B is rinsed with DIW.

3) After being treated with the third treatment liquid DHF in the third washing tank C, the same washing tank C is rinsed with DIW.

4) The final rinse with DIW is performed in the fourth washing tank D.

5) Finally, the drying process is performed by the drying unit G, and the substrate is unloaded in the transfer carrier cassette in the substrate unloading unit H and is transported to the next process.

Embodiment 3
This embodiment is shown in FIG. 3, and the cleaning method of Embodiment 1 is applied to a one-bus type cleaning apparatus.

  This one-bath type substrate cleaning section is composed of one or more (two in the illustrated case) multifunctional cleaning tanks I and J that can be cleaned with a plurality of types of processing liquids (cleaning liquids). Substrates transferred from the carrier cassette for conveyance in the substrate carry-in unit E to the substrate conveyance processing robot of the substrate conveyance processing unit F are immersed in each of the multifunctional cleaning tanks I or J by the substrate conveyance processing robot, The substrates immersed in these two multifunctional cleaning tanks I and J are simultaneously cleaned in parallel.

In particular,
1) The substrate put into each of the cleaning tanks I and J is treated with the first treatment liquid APM, rinsed with ammonia water, hydrogen water, or a mixture of these ammonia water and hydrogen water, and further DIW Rinse.

2) After being treated with the second treatment liquid HPM, it is rinsed with DIW.

3) After being treated with DHF, which is the third treatment liquid, rinsing is performed with DIW.

4) Finally, it is dried by the drying unit G, and is stored again in the carrier cassette for conveyance in the substrate carry-out unit h and carried out to the next process.

Embodiment 4
This embodiment is shown in FIG. 4 and applies the cleaning method of Embodiment 1 to a combination type cleaning apparatus in which a multi-function cleaning tank and a single-function cleaning tank are combined.

  This combination type substrate cleaning section includes one or a plurality of (two in the illustrated example) multi-functional cleaning tanks K and M that can be cleaned with a plurality of types of processing liquids (cleaning liquids), and a dedicated processing liquid ( A plurality of (in the illustrated case, two) single-function cleaning tanks L and N that can be cleaned with a cleaning solution), and a substrate carrying section E to transfer the substrate from the carrier cassette The substrate transferred to the substrate transfer processing robot of the transfer processing unit F is immersed in each of the multifunction cleaning tanks K and M or the single function cleaning tanks L and N by the substrate transfer processing robot. The substrates immersed in the two multifunctional cleaning tanks K and M are simultaneously cleaned in parallel.

In particular,
1) The substrate put into each multifunction cleaning tank K, M is processed with the first processing liquid APM.

2) The substrate is put into the single-function cleaning tanks L and N, rinsed with ammonia water or hydrogen water, or a mixed solution of ammonia water and hydrogen water, and further rinsed with DIW.

3) The substrate is reintroduced into the multi-function cleaning tanks K and M and processed with the second processing liquid HPM.

4) The substrate is recharged into the single function cleaning tanks L and N and rinsed with DIW.

5) The substrate is reintroduced into the multi-function cleaning tanks K and M and processed with DHF which is the third processing liquid.

6) The substrate is reintroduced into the single-function cleaning tanks L and N, and finally rinsed with DIW.

7) Finally, it is dried by the drying unit G, and is again stored in the carrier cassette for conveyance in the substrate carry-out unit H and carried out to the next process.

Embodiment 5
This embodiment is shown in FIG. 5, and the cleaning method of Embodiment 1 is applied to a single wafer cleaning apparatus.

  The cleaning unit of the single wafer cleaning apparatus includes a rotary table 11 that supports and rotates a single substrate W in a horizontal state in a cleaning housing 10, and a cleaning chamber 12 that can move up and down relative to the rotary table 11. And the chemical | medical solution supply means 13 which supplies a process liquid is comprised as a main part.

  Specifically, the cleaning chamber 12 includes a plurality of annular processing tanks 14 to 17 arranged in the vertical direction on the inner peripheral portion thereof, and can be moved up and down with respect to the rotary table 11. The substrate W that is configured and placed on the turntable 11 is subjected to a cleaning process corresponding to one of the annular processing tanks 14 to 17.

In particular,
1) The substrate W is rotated in a state corresponding to the annular processing tank 14, and the first processing liquid APM is dropped from the chemical solution supply unit 13 onto the upper surface of the substrate W and processed.

2) Ammonia water, hydrogen water, or a mixture of these ammonia water and hydrogen water is dropped from the chemical solution supply unit 13 onto the upper surface of the substrate W and rinsed, and then rinsed with DIW.

3) The substrate W is rotated in a state corresponding to the annular processing tank 15, and the second processing liquid HPM is dropped from the chemical solution supply unit 13 onto the upper surface of the substrate W and processed.

4) DIW is dropped from the chemical solution supply unit 13 onto the upper surface of the substrate W and rinsed.

5) The substrate W is rotated in a state corresponding to the annular processing tank 16, and DHF, which is the third processing liquid, is dropped onto the upper surface of the substrate W from the chemical solution supply unit 13 and processed.

6) Final rinse with DIW.

Finally, the substrate W is rotated at a high speed in a state corresponding to the annular processing tank 17 and spin-dried.

  In addition, Embodiment 1-5 mentioned above shows the suitable embodiment of this invention to the last, This invention is not limited to this, A various design change is possible within the range.

  For example, in the substrate cleaning methods according to the first to fifth embodiments, a rinsing process using DIW is provided after a rinsing process using a weak alkaline solution after APM treatment. Depending on the concentration of the weak alkaline solution, the rinsing process using DIW may be performed. The process may be omitted.

  The present invention can be used for cleaning a substrate to be processed such as a semiconductor substrate, a liquid crystal glass substrate, and a plasma display substrate.

It is a process-process figure which shows the washing | cleaning method of the board | substrate which is one Embodiment of this invention. It is a schematic block diagram of a one-bus type substrate cleaning apparatus. It is a schematic block diagram of a multi-bus type substrate cleaning apparatus. It is a schematic block diagram of a combination type substrate cleaning apparatus. It is a schematic block diagram of the washing | cleaning part of a single wafer washing | cleaning apparatus. It is a process drawing which shows the washing | cleaning method of the conventional board | substrate.

Explanation of symbols

1 APM (ammonia overwater)
2a Ammonia water 2b Hydrogen water 2c Ammonia water + hydrogen water 3, 5, 7 DIW (ultra pure water)
4 HPM (hydrochloric acid excess water)
6 DHF (dilute hydrofluoric acid)
8 Drying 10 Cleaning housing 11 Rotary table 12 Cleaning chamber 13 Chemical solution supply unit 14, 15, 16, 17 annular processing tank A, B, C, D, L, N Single function cleaning tank E Substrate carry-in section F Substrate transport processing section G Drying section H Substrate unloading section I, J, K, M Multi-function cleaning tank W Substrate

Claims (8)

A method of cleaning a substrate in which a substrate is cleaned using a plurality of cleaning liquids sequentially according to a cleaning recipe,
A method for cleaning a substrate, comprising an APM treatment step for treating a substrate with at least APM, wherein a rinsing step with a weak alkaline solution is provided after the APM treatment step. 2. The substrate cleaning method according to claim 1, wherein ammonia water is used as the weak alkaline solution. The method for cleaning a substrate according to claim 1, wherein hydrogen water is used as the weak alkaline solution. The substrate cleaning method according to claim 1, wherein a mixed solution of ammonia water and hydrogen water is used as the weak alkaline solution. 5. The method according to claim 1, wherein the cleaning method is applied to a multi-bath type cleaning apparatus including a plurality of single-function cleaning tanks that can be cleaned with a dedicated cleaning solution. A method for cleaning a substrate as described. 5. The method according to claim 1, wherein the cleaning method is applied to a one-bath type cleaning apparatus including a multifunction cleaning tank capable of performing a cleaning process with a plurality of types of cleaning liquids. Substrate cleaning method. The above-described cleaning method is applied to a multi-bus type cleaning apparatus including a multi-functional cleaning tank capable of performing a cleaning process with a plurality of types of cleaning liquids and a single function cleaning tank capable of performing a cleaning process with a dedicated cleaning liquid. The method for cleaning a substrate according to any one of claims 1 to 4. 5. The substrate cleaning method according to claim 1, wherein the cleaning method is applied to a single wafer cleaning apparatus capable of cleaning a single substrate with a plurality of types of cleaning liquids.

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