JP2013045961A - Substrate cleaning method, substrate cleaning liquid and substrate processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate cleaning method capable of cleaning the substrate surface where a germanium layer is exposed while combining inhibition of film reduction of the germanium layer and excellent cleaning efficiency.SOLUTION: In the substrate cleaning method, cleaning liquid is supplied to the substrate surface where a germanium layer is exposed, and ozone water having pH adjusted to a value larger than 7 by adding an alkaline substance is used as the cleaning liquid. The substrate processing apparatus includes a spin chuck 12 which holds a substrate W having the surface where the germanium layer is exposed, and a cleaning liquid supply mechanism 20 which supplies the cleaning liquid, consisting of the ozone water having pH adjusted to a value larger than 7 by adding the alkaline substance, to the surface of the substrate W held by the spin chuck 12.

Description

  The present invention relates to a substrate cleaning method, a substrate cleaning liquid, and a substrate processing apparatus for cleaning a substrate surface from which a germanium layer is exposed.

Miniaturization of semiconductor devices using silicon is reaching the limit, and reduction of power consumption is also a major issue. Thus, germanium, which has higher mobility than silicon, has attracted attention as a semiconductor material that can replace silicon.
In the manufacturing process of a semiconductor device, a cleaning process for removing unnecessary materials from the surface of the semiconductor substrate is indispensable. An example of the cleaning liquid for removing foreign substances from the surface of the silicon substrate is an ammonia hydrogen peroxide solution mixture (NH ₄ OH / H ₂ O ₂ / H ₂ O). When the ammonia hydrogen peroxide solution mixture is supplied to the silicon substrate surface, a silicon oxide layer is formed by oxidation with the hydrogen peroxide solution in the mixture, and the silicon oxide layer is etched in a small amount by the ammonia water in the mixture solution. Is done. Thereby, the foreign matter on the silicon substrate surface is lifted off together with the silicon oxide layer. This is the mechanism of cleaning with ammonia hydrogen peroxide solution.

JP 2004-281463 A US Pat. No. 7,569,493

  The present inventor applied ammonia hydrogen peroxide solution to the cleaning of the substrate surface where the germanium layer was exposed, and verified its validity. As a result, it was found that an unacceptable loss (film loss) occurs in the germanium layer. One reason for this is presumed to be that germanium oxide generated on the surface of the germanium layer by oxidation with hydrogen peroxide solution is dissolved in water. That is, the oxidation of the surface of the germanium layer and the etching of the germanium oxide generated thereby proceed at a high speed, and the film reduction of the germanium layer proceeds at a high speed.

FIG. 15 shows the results of examining the relationship between the concentration of the ammonia hydrogen peroxide solution mixture and the film loss rate of the germanium layer (Ge loss rate; the amount of film loss due to liquid supply for one minute). The horizontal axis represents the dilution ratio (volume ratio) x of water (DIW: deionized water) in ammonia hydrogen peroxide water.
Even if the ammonia hydrogen peroxide solution is in an ultra-diluted state of NH ₄ OH: H ₂ O ₂ : DIW = 1: 1: 20000 and the processing time is shortened, the allowable limit for device fabrication (for example, 3 nm) is exceeded. Film loss may occur. More specifically, in order to reliably clean the entire surface of the substrate, it is necessary to supply the cleaning liquid to the substrate surface for at least about 30 seconds. However, from the results of FIG. 15, it can be seen that even with the ultra-diluted ammonia hydrogen peroxide solution mixture, a film loss of about 5 nm occurs when supplied for 30 seconds. If the supply of the ammonia hydrogen peroxide solution mixture is limited to a few seconds, the problem of film reduction may be solved, but the substrate may not be sufficiently cleaned. In addition, it is extremely difficult to limit the supply of the processing liquid to a few seconds by the processing liquid supply control by the substrate processing apparatus. Furthermore, it is not easy to stably purify the ammonia hydrogen peroxide solution mixture in the ultra-diluted state as described above. For example, it is conceivable to provide a unit for two-stage dilution that performs 100-fold dilution in the first stage and 200-fold dilution in the second stage, but a significant reduction in productivity is inevitable.

  Accordingly, an object of the present invention is to provide a substrate cleaning method, a substrate cleaning liquid, and a substrate processing apparatus that can clean the surface of the substrate on which the germanium layer is exposed and that can achieve both a reduction in film thickness of the germanium layer and excellent cleaning efficiency. is there.

The present invention relates to a substrate cleaning method for supplying a cleaning liquid to a substrate surface from which a germanium layer is exposed, wherein ozone water whose pH is adjusted to a value greater than 7 by adding an alkaline substance is used as the cleaning liquid. (Claim 1).
Ozone water can be easily supplied continuously at an oxidant concentration as low as 0.5 ppm to 20 ppm. The oxidant concentration in the super-diluted ammonia hydrogen peroxide solution mixture (NH ₄ OH: H ₂ O ₂ : DIW = 1: 1: 20000) is 17 ppm. Therefore, ozone water is suitable as an alternative solution for the super-diluted ammonia hydrogen peroxide solution mixture in terms of oxidant concentration.

  On the other hand, the zeta potential of the substance that constitutes the substrate and the substance that constitutes the foreign substance is deeply involved in the removal performance of the foreign substance on the substrate. The behavior of the zeta potential of the substrate material and the foreign matter on the substrate is disclosed in, for example, Patent Document 2. According to this, in the region where the pH is higher than 7 (more preferably, the region of 8 or more), the zeta potential of each material becomes a negative value. Therefore, if the pH is higher than 7, the materials have the same polarity potential, and repulsive force is generated between the materials. As a result, foreign substances are less likely to adhere to the substrate. That is, the foreign matter is easily separated from the substrate and is less likely to reattach to the substrate.

  Furthermore, the present inventor investigated the relationship between the film thickness reduction of the germanium layer and the foreign matter removal rate. As a result, it was found that in the ultra-diluted ammonia hydrogen peroxide water mixed solution described above, a film loss of the germanium layer was about 2 nm when trying to obtain a foreign matter removal rate of 100%. Although this film reduction is within an allowable range, the problem in the case of using a super-diluted ammonia hydrogen peroxide solution mixture as a cleaning solution is as described above. On the other hand, when ozone water was used as the cleaning liquid, it was found that a film loss exceeding 3 nm occurred when trying to obtain a foreign matter removal rate of 100%. On the other hand, when the present inventor adds an alkaline substance to ozone water and adjusts the pH, the larger the pH, the less the germanium layer film decrease at a foreign matter removal rate of 100%. As a result, it was found that the film thickness of the germanium layer can be reduced to 3 nm or less, and the present invention has been completed.

That is, according to the present invention, the substrate is cleaned using ozone water whose pH is adjusted to a value greater than 7 by the addition of an alkaline substance, so that the germanium layer is exposed while suppressing the reduction of the germanium layer. Precise cleaning of the substrate surface can be realized.
The alkaline substance preferably contains one or more selected from the group consisting of ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide (TMAH), and choline (Claim 2).

Moreover, it is preferable that the oxidizing agent density | concentration of the said washing | cleaning liquid is 0.5 ppm-20 ppm. Thereby, it becomes the oxidizing agent density | concentration comparable as the ammonia hydrogen peroxide aqueous solution mixture of a super dilution state.
More preferably, the cleaning liquid has a pH adjusted to 9.5 or higher by addition of an alkaline substance. As a result, the film reduction rate of the germanium layer does not depend much on the oxidant concentration, so that it is not necessary to strictly control the oxidant concentration.

  Furthermore, the present invention provides a cleaning liquid for cleaning the substrate surface from which the germanium layer is exposed, wherein the pH is adjusted to a value greater than 7 (more preferably 9.5 or more) by adding an alkaline substance. A substrate cleaning solution is provided (claim 4). The substrate cleaning method described above can be carried out using this substrate cleaning liquid. Also in this case, it is preferable that the alkaline substance contains one or more selected from the group consisting of ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide (TMAH), and choline (Claim 5). Moreover, it is preferable that an oxidizing agent density | concentration is 0.5 ppm-20 ppm (Claim 6).

  The present invention also provides a substrate holding means for holding a substrate having a surface with an exposed germanium layer, and a pH value greater than 7 (more preferably) by adding an alkaline substance to the surface of the substrate held by the substrate holding means. And a cleaning solution supply means for supplying a cleaning solution made of ozone water adjusted to 9.5 or higher). With this configuration, the above-described substrate cleaning method can be performed on the substrate held by the substrate holding unit. Also in this case, it is preferable that the alkaline substance contains one or more selected from the group consisting of ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide (TMAH), and choline (Claim 8). Moreover, it is preferable that the oxidizing agent density | concentration of the said washing | cleaning liquid is 0.5 ppm-20 ppm.

More specifically, it is preferable that the cleaning liquid supply means includes a mixing means for preparing the cleaning liquid (claim 10).
In one embodiment of the present invention, the blending means is coupled to an alkaline aqueous solution supply pipe for circulating an alkaline aqueous solution, a mixing unit provided in the middle of the alkaline aqueous solution supply pipe, and the mixing unit. And ozone water piping through which ozone water is circulated (claim 11). That is, by mixing and mixing ozone water with the alkaline aqueous solution flowing through the alkaline aqueous solution supply pipe, a continuous flow of ozone water adjusted in pH can be formed, and such ozone water can be continuously supplied.

  In another embodiment of the present invention, the blending means is coupled to an alkaline aqueous solution supply pipe for circulating an alkaline aqueous solution, a gas dissolution unit provided in the middle of the alkaline aqueous solution supply pipe, and the gas dissolution unit, And an ozone gas pipe for circulating ozone gas toward the gas dissolving unit. According to this configuration, the ozone gas is dissolved in the alkaline aqueous solution flowing through the alkaline aqueous solution supply pipe, whereby a continuous flow of ozone water having a pH adjusted can be formed, and such ozone water can be continuously supplied.

  In still another embodiment of the present invention, the blending means is coupled to an ozone water supply pipe for circulating ozone water, a mixing unit provided in the middle of the ozone water supply pipe, and the mixing unit. And an alkaline aqueous solution pipe for circulating the alkaline aqueous solution toward the unit. According to this configuration, by mixing and dissolving the alkaline aqueous solution in the ozone water flowing through the ozone water supply pipe, it is possible to form a continuous flow of ozone water whose pH is adjusted, and such ozone water can be continuously supplied.

  In still another embodiment of the present invention, the blending means is coupled to an ozone water supply pipe for circulating ozone water, a gas dissolution unit provided in the middle of the ozone water supply pipe, and the gas dissolution unit, And an alkali gas pipe for circulating an alkali gas toward the gas dissolving unit. According to this configuration, by dissolving the alkali gas in the ozone water flowing through the ozone water supply pipe, a continuous flow of the ozone water adjusted in pH can be formed, and such ozone water can be continuously supplied.

The substrate holding means may be configured to hold a single substrate, and the substrate processing apparatus may be a single wafer type substrate processing apparatus that processes substrates one by one. In this case, the substrate processing apparatus may include a substrate rotating unit that rotates the substrate held by the substrate holding unit, and a nozzle that supplies a cleaning liquid toward the substrate held by the substrate holding unit. Good.
The substrate holding means is configured to collectively hold a plurality of substrates, and the substrate processing apparatus collectively immerses the plurality of substrates held by the substrate holding means in the cleaning liquid. It may be a batch type substrate processing apparatus having a cleaning tank.

FIGS. 1A to 1E are schematic cross-sectional views for explaining a manufacturing process of a MISFET (Metal-Insulator-Semiconductor Field-Effect-Transistor) using a germanium layer as a channel layer. Figure 2 shows the relationship between the Ge loss of the germanium layer and the foreign matter removal rate by cleaning the substrate with the germanium layer exposed using ozone water adjusted to pH by adding ammonia. The result of having investigated is shown. FIG. 3 shows, as a comparative example, the result of examining the relationship between the reduction of the germanium layer and the foreign matter removal rate by cleaning the substrate with the germanium layer exposed in a superdiluted ammonia hydrogen peroxide solution. Indicates. FIG. 4 shows the results of investigating the behavior of germanium layer film decrease with respect to pH for a mixed solution of ammonia hydrogen peroxide and ozone water (pH adjusted with ammonia). FIG. 5 shows the configuration of the substrate processing apparatus according to the first embodiment of the present invention. FIG. 6 shows the configuration of a substrate processing apparatus according to the second embodiment of the present invention. FIG. 7 shows the configuration of a substrate processing apparatus according to the third embodiment of the present invention. FIG. 8 shows the configuration of a substrate processing apparatus according to the fourth embodiment of the present invention. FIG. 9 shows the configuration of a substrate processing apparatus according to the fifth embodiment of the present invention. FIG. 10 shows the configuration of a substrate processing apparatus according to the sixth embodiment of the present invention. FIG. 11 shows the configuration of a substrate processing apparatus according to the seventh embodiment of the present invention. FIG. 12 shows the configuration of the substrate processing apparatus according to the eighth embodiment of the present invention. FIG. 13 shows the configuration of a substrate processing apparatus according to the ninth embodiment of the present invention. FIG. 14 shows the configuration of a substrate processing apparatus according to the tenth embodiment of the present invention. FIG. 15 shows the results of examining the relationship between the concentration of the ammonia hydrogen peroxide solution mixture and the film reduction rate of the germanium layer (the amount of film reduction by supplying the liquid for one minute).

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIGS. 1A to 1E are schematic cross-sectional views for explaining a manufacturing process of a MISFET (Metal-Insulator-Semiconductor Field-Effect-Transistor) using a germanium layer as a channel layer. As shown in FIG. 1A, a SiGe buffer layer 2 is formed on a silicon substrate 1, and the buffer layer 2 is separated by an STI (Shallow Trench Isolation) structure 4. From this state, as shown in FIG. 1B, the surface layer portion of the SiGe buffer layer 2 is etched to expose the clean surface 2a. On the clean surface 2a, as shown in FIG. 1C, a germanium layer 3 as a channel layer is epitaxially grown. Thereafter, as shown in FIG. 1 (d), a gate structure 5 is formed on the germanium layer 3. The gate structure 5 includes, for example, a high-k metal layer 6 in contact with the germanium layer 3 and a gate metal layer 7 stacked on the high-k metal layer 6. The high-k metal layer 6 may be made of, for example, a titanium nitride (TiN) layer. The gate metal layer 7 may be made of, for example, a tungsten (W) layer. The gate structure 5 is formed in a belt-like pattern that exposes the germanium layer 3 on both sides thereof. Spacers 8 (sidewalls) are formed on both side walls of the gate structure 5 as shown in FIG.

After the epitaxial growth step of the germanium layer 3 (FIG. 1C), after the step of forming the gate structure 5 (FIG. 1D) and after the step of forming the spacer 8 (FIG. 1E), The germanium layer 3 is exposed on the substrate surface. A substrate cleaning process is performed on the substrate in this state in order to remove foreign substances on the surface.
In this embodiment, ozone water whose pH is adjusted to a value higher than 7 (preferably, 9.5 or more) by adding an alkaline substance is used as the cleaning liquid in this embodiment. As the alkaline substance to be added, one or more selected from the group consisting of ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide (TMAH. (CH3) 4NOH aqueous solution), and choline can be used. Hereinafter, an example using ammonia will be described.

Figure 2 shows the relationship between the Ge loss of the germanium layer and the foreign matter removal rate by cleaning the substrate with the germanium layer exposed using ozone water adjusted to pH by adding ammonia. The result of having investigated is shown. For comparison, similar experimental results with ozone water (pH 7) not adjusted for pH are also shown.
The foreign matter removal rate refers to a ratio of the fine particles removed from the wafer (substrate) to which fine particles are attached in advance. Specifically, the number N ₀ of particles on the wafer surface is measured, and then the number of particles N ₁ on the wafer surface is measured by attaching particles (for example, Si ₃ N ₄ particles) to the surface of the wafer. The number N ₂ of particles on the wafer surface is measured. The foreign matter removal rate in this case is calculated by the following equation.

Foreign matter removal rate (%) = 100 × (N ₁ −N ₂ ) / (N ₁ −N ₀ )
FIG. 2 shows that the foreign substance removal rate with respect to the film reduction of the germanium layer rises sharply as the pH increases, and the film reduction at the foreign substance removal rate of 100% decreases. Then, it can be seen that by adjusting the pH to be higher than 7, the film thickness reduction of the germanium layer at a foreign matter removal rate of 100% can be reduced to 3 nm or less.

  FIG. 3 shows, as a comparative example, the result of examining the relationship between the reduction of the germanium layer and the foreign matter removal rate by cleaning the substrate with the germanium layer exposed in a superdiluted ammonia hydrogen peroxide solution. Indicates. From FIG. 3, it can be seen that in the ultra-diluted ammonia hydrogen peroxide aqueous solution, a reduction in the germanium layer thickness of about 2 nm occurs when trying to obtain a foreign matter removal rate of 100%. Although this film reduction is within an allowable range, the problem in the case of using a superdiluted ammonia hydrogen peroxide solution mixture as the cleaning solution is as described above in the section “Problems to be solved by the invention”. .

  From the comparison between FIG. 2 and FIG. 3, it can be seen that by adjusting the pH to 9 or more, it is possible to achieve a film reduction and a foreign matter removal rate equivalent to the super-diluted ammonia hydrogen peroxide solution mixture. Furthermore, it can be seen from FIG. 2 that by adjusting the pH to 10 or more, a foreign matter removal rate of 100% can be achieved while suppressing the film loss of the germanium layer to a negligible level (0.5 nm or less).

FIG. 4 shows the results of investigating the behavior of germanium layer film decrease with respect to pH for a mixed solution of ammonia hydrogen peroxide and ozone water (pH adjusted with ammonia). The pH of the ammonia hydrogen peroxide solution mixture was adjusted by increasing the mixing ratio of ammonia water to hydrogen peroxide solution. The pH when the hydrogen peroxide solution is a single solution is 7. The pH of the ozone water was adjusted by adding ammonia water (NH ₄ OH) to the ozone water. However, for reference, experimental results A and B are also shown for a sample in which hydrochloric acid was added to adjust the pH to less than 7. The pH of the single ozone water solution is 7. Each solution was adjusted so that the oxidant concentration was kept constant and only the pH was changed.

  From FIG. 4, the ammonia hydrogen peroxide solution mixed solution and ozone water adjusted to pH with ammonia water have completely different behaviors of germanium layer film reduction with respect to pH, although they have the same chemical composition of oxidizing agent and ammonia. I understand that. That is, in the ammonia hydrogen peroxide solution mixture, the rate of reduction of the germanium layer film increases as the ratio of ammonia water increases and the pH increases. On the other hand, in the ozone water added with ammonia, the rate of decrease of the germanium layer film decreases as the pH increases.

  2 and FIG. 4, the conclusion is that ozone water whose pH is adjusted to a value higher than 7 by adding an alkaline substance such as ammonia is a mixture of ammonia and hydrogen peroxide with respect to cleaning of the substrate with the germanium layer exposed. Is an optimal cleaning solution that exhibits completely different behavior and can achieve both foreign substance removal performance and suppression of germanium layer film loss. This tendency becomes more prominent as the pH increases.

  When analyzing in more detail, it can be seen from the results of FIG. 4 that in the region where the pH is 9.5 or higher, the film reduction rate of germanium or the like does not depend on the oxidizing agent concentration of ozone water. Therefore, by using ozone water whose pH is adjusted to 9.5 or higher by adding an alkaline substance as a cleaning liquid, excellent foreign matter removal performance and germanium layer film can be obtained without precisely controlling the oxidizing agent concentration of ozone water. Both reduction and suppression can be achieved.

FIG. 5 is a diagram showing the configuration of the substrate processing apparatus according to the first embodiment of the present invention. In order to clean the substrate W with ozone water to which the pH is adjusted to a value larger than 7 by adding an alkaline substance. The apparatus is shown. The substrate W is a substrate with a germanium layer exposed on the surface as shown in FIGS. 1 (c), (d), and (e).
This substrate processing apparatus is a single-wafer type substrate processing apparatus that processes substrates W one by one, and includes a processing chamber 10, a processing cup 11 accommodated in the processing chamber 10, and a spin disposed in the processing cup 11. A chuck 12 (substrate holding means) and a processing liquid nozzle 13 are included.

  The spin chuck 12 is provided so as to be rotatable about a vertical axis while holding the substrate W in a horizontal posture. The spin chuck 12 has a rotating shaft 14 extending along the vertical direction. The rotary shaft 14 is rotationally driven by a rotary drive mechanism 15 (substrate rotating means) such as an electric motor. The processing liquid nozzle 13 is provided at the tip of the processing liquid pipe 16 and is configured to discharge the processing liquid toward the upper surface of the substrate W held by the spin chuck 12. The processing liquid deposited on the substrate W held by the spin chuck 12 receives a centrifugal force on the rotating substrate W, spreads outward, and jumps out of the substrate W. The protruding processing liquid is received by the processing cup 11 and is discharged or collected.

The processing liquid pipe 16 is connected to the cleaning liquid supply mechanism 20 and is configured to receive the supply of the cleaning liquid from the cleaning liquid supply mechanism 20. The cleaning liquid supply mechanism 20 includes a first mixing unit 21, a second mixing unit 22, a deionized water pipe 23, an ammonia water pipe 24, and an ozone water pipe 25, which constitute a blending means. .
The deionized water pipe 23 connects between the deionized water supply source 26 and the first mixing unit 21, and supplies deionized water from the deionized water supply source 26 to the first mixing unit 21. In the middle of the deionized water pipe 23, a flow rate adjustment valve 27 and an on-off valve 28 are interposed. The ammonia water pipe 24 connects between the ammonia water supply source 31 and the first mixing unit 21, and supplies ammonia water from the ammonia water supply source 31 to the first mixing unit 21. A flow rate adjustment valve 32 and an opening / closing valve 33 are interposed in the middle of the ammonia water pipe 24.

  The first mixing unit 21 is configured to inject ammonia water from the ammonia water pipe 24 into the flow path of deionized water from the deionized water pipe 23, thereby generating diluted ammonia water. Yes. The diluted ammonia water is guided to the ammonia water supply pipe 35 (alkaline aqueous solution supply pipe). The ammonia water supply pipe 35 is coupled to the processing liquid pipe 16. The second mixing unit 22 is provided in the middle of the ammonia water supply pipe 35.

  The second mixing unit 22 is configured to inject ozone water from the ozone water pipe 25 into the ammonia water flow path from the ammonia water supply pipe 35, thereby generating ozone water whose pH is adjusted with ammonia. Has been. The ozone water pipe 25 connects between the ozone water supply source 36 and the second mixing unit 22, and supplies ozone water from the ozone water supply source 36 to the second mixing unit 22. In the middle of the ozone water pipe 25, a flow rate adjustment valve 37 and an opening / closing valve 38 are interposed.

The flow rate adjustment valve 27 adjusts the flow rate of deionized water to 1550 milliliters / minute, for example. The flow rate adjusting valve 32 adjusts the flow rate of ammonia water to 70 ml / min, for example. Accordingly, diluted ammonia water flows through the ammonia water supply pipe 35 at a flow rate of 1620 ml / min. For example, the flow rate adjustment valve 37 adjusts the flow rate of ozone water to 180 ml / min. The oxidant concentration of ozone water supplied from the ozone water pipe 25 may be 10 ppm. In this case, finally, 1 ppm ozone water mixed with ammonia water is supplied from the processing liquid pipe 16 to the processing liquid nozzle 13 at a flow rate of 1800 ml / min, and is supplied to the surface of the substrate W as a cleaning liquid. . The cleaning liquid in this case is O ₃ / NH ₄ OH mixed with aqueous ammonia at a ratio of 1730: 70. When the ammonia water concentration supplied by the ammonia water supply source 31 is 8.97 wt%, the ammonia concentration in the cleaning liquid is 0.34 wt%.

With such a configuration, it is possible to perform a cleaning process on the substrate W using ozone water whose pH is adjusted with ammonia as a cleaning liquid.
FIG. 6 is a view for explaining the configuration of a substrate processing apparatus according to the second embodiment of the present invention. In FIG. 6, the same reference numerals are given to the portions corresponding to the configuration shown in FIG. 5 described above. This substrate processing apparatus is a batch-type substrate processing apparatus that processes a plurality of substrates W at once. Specifically, the substrate processing apparatus includes a processing tank 17 (cleaning tank) connected to the cleaning liquid supply mechanism 20 by a processing liquid pipe 16 and a substrate that holds a plurality of substrates W in the processing tank 17 collectively. And holding mechanism 18 (substrate holding means). The substrate holding mechanism 18 is configured to hold, for example, a plurality of substrates W in a vertical posture stacked in the horizontal direction. The processing tank 17 stores the cleaning liquid supplied from the cleaning liquid supply mechanism 20 therein, and is configured to immerse the plurality of substrates W held by the substrate holding mechanism 18 in the stored cleaning liquid. .

With this configuration, a plurality of substrates W can be collectively subjected to a process (substrate cleaning process) using a cleaning liquid made of ozone water whose pH is adjusted with ammonia.
FIG. 7 is a view for explaining the configuration of a substrate processing apparatus according to the third embodiment of the present invention. In FIG. 7, the same reference numerals are given to portions corresponding to the configuration shown in FIG. 5 described above.
This substrate processing apparatus is a single-wafer type substrate processing apparatus that processes the substrates W one by one, similar to the apparatus of FIG. 5, and the configuration of the cleaning liquid supply mechanism 20 is different from the apparatus of FIG. In this embodiment, the ozone water pipe 25 is connected to the first mixing unit 21, and the ammonia water pipe 24 is connected to the second mixing unit 22. Therefore, the first mixing unit 21 is configured to inject ozone water from the ozone water pipe 25 into the flow path of deionized water from the deionized water pipe 23, thereby generating diluted ozone water. Has been. The diluted ozone water is guided to the ozone water supply pipe 39. The ozone water supply pipe 39 is coupled to the processing liquid pipe 16. The second mixing unit 22 is provided in the middle of the ozone water supply pipe 39.

The second mixing unit 22 is configured to inject ammonia water from the ammonia water pipe 24 into the ozone water flow path from the ozone water supply pipe 39, thereby generating ozone water whose pH is adjusted with ammonia. Has been.
The flow rate adjustment valve 27 adjusts the flow rate of deionized water to 1550 milliliters / minute, for example. The flow rate adjusting valve 32 adjusts the flow rate of ammonia water to 70 ml / min, for example. For example, the flow rate adjustment valve 37 adjusts the flow rate of ozone water to 180 ml / min. The oxidant concentration of ozone water supplied from the ozone water pipe 25 may be 10 ppm. In this case, finally, 1 ppm ozone water mixed with ammonia water is supplied from the processing liquid pipe 16 to the processing liquid nozzle 13 at a flow rate of 1800 ml / min, and is supplied to the surface of the substrate W as a cleaning liquid. . The cleaning liquid in this case is O ₃ / NH ₄ OH mixed with aqueous ammonia at a ratio of 1730: 70. When the ammonia water concentration supplied by the ammonia water supply source 31 is 8.97 wt%, the ammonia concentration in the cleaning liquid is 0.34 wt%.

With such a configuration, it is possible to perform a cleaning process on the substrate W using ozone water whose pH is adjusted with ammonia as a cleaning liquid.
FIG. 8 is a view for explaining the configuration of a substrate processing apparatus according to the fourth embodiment of the present invention. In FIG. 8, the same reference numerals are given to the portions corresponding to the configurations shown in FIG. 6 and FIG. This substrate processing apparatus is a batch type substrate processing apparatus that performs a process on a plurality of substrates W at once as in the apparatus of FIG. The cleaning liquid supply mechanism 20 is combined with the configuration shown in FIG. Even with such a configuration, a plurality of substrates W can be collectively subjected to a treatment (substrate cleaning treatment) with a cleaning liquid made of ozone water whose pH is adjusted with ammonia.

  FIG. 9 is a view for explaining the configuration of a substrate processing apparatus according to the fifth embodiment of the present invention. In FIG. 9, the same reference numerals are given to portions corresponding to the configuration shown in FIG. 5 described above. This substrate processing apparatus is a single-wafer type substrate processing apparatus that processes the substrates W one by one, similar to the apparatus of FIG. 5, and the configuration of the cleaning liquid supply mechanism 20 is different from the apparatus of FIG. In this embodiment, instead of the second mixing unit 22, a gas dissolving unit 40 is interposed in the middle of the ammonia water supply pipe 35. In the gas dissolving unit 40, ozone gas is dissolved in diluted ammonia water, thereby generating ozone water whose pH is adjusted by ammonia.

  Specifically, one end of an ozone gas pipe 41 is connected to the gas dissolving unit 40. The other end of the ozone gas pipe 41 is connected to an ozone gas supply source 42. In the middle of the ozone gas pipe 41, a flow rate adjustment valve 43 and an on-off valve 44 are interposed. As the gas dissolving unit 40, for example, a semipermeable membrane that does not transmit liquid but transmits only gas can be used.

  With such a configuration, in the mixing unit 21, ammonia water is injected into deionized water to generate diluted ammonia water. Ozone gas is dissolved in the diluted ammonia water in the gas dissolving unit 40. Thereby, the pH-adjusted ozone water is generated. The ozone water is supplied from the processing liquid pipe 16 to the processing liquid nozzle 13 and supplied to the surface of the substrate W as a cleaning liquid. Thus, the cleaning process can be performed on the substrate W using ozone water whose pH is adjusted with ammonia as the cleaning liquid.

  FIG. 10 is a view for explaining the configuration of a substrate processing apparatus according to the sixth embodiment of the present invention. In FIG. 10, the same reference numerals are assigned to the portions corresponding to the configurations shown in FIGS. 6 and 9 described above. This substrate processing apparatus is a batch type substrate processing apparatus that performs a process on a plurality of substrates W at once as in the apparatus of FIG. Then, the configuration shown in FIG. 9 is combined as the cleaning liquid supply mechanism 20. Even with such a configuration, a plurality of substrates W can be collectively subjected to a treatment (substrate cleaning treatment) with a cleaning liquid made of ozone water whose pH is adjusted with ammonia.

  FIG. 11 is a view for explaining the configuration of a substrate processing apparatus according to the seventh embodiment of the present invention. In FIG. 11, the same reference numerals are given to portions corresponding to the configuration shown in FIG. 7 described above. This substrate processing apparatus is a single-wafer type substrate processing apparatus that processes the substrates W one by one, similar to the apparatus of FIG. 7, and the configuration of the cleaning liquid supply mechanism 20 is different from the apparatus of FIG. In this embodiment, a gas dissolution unit 46 is provided in the middle of the ozone water supply pipe 39 instead of the second mixing unit 22. In the gas dissolving unit 46, ammonia gas is dissolved in ozone water, thereby generating ozone water whose pH is adjusted by ammonia.

  Specifically, one end of an ammonia gas pipe 47 (alkali gas pipe) is connected to the gas dissolving unit 46. The other end of the ammonia gas pipe 47 is connected to an ammonia gas supply source 48. In the middle of the ammonia gas pipe 47, a flow rate adjusting valve 49 and an on-off valve 50 are interposed. As the gas dissolution unit 46, the same one as the gas dissolution unit 40 of the fifth embodiment (FIG. 9) can be used.

  With such a configuration, the mixing unit 21 generates ozone water diluted with ozone water injected into deionized water. The ammonia gas is dissolved in the diluted ozone water in the gas dissolving unit 46, so that the pH-adjusted ozone water is generated. The ozone water is supplied from the processing liquid pipe 16 to the processing liquid nozzle 13 and supplied to the surface of the substrate W as a cleaning liquid. Thus, the cleaning process can be performed on the substrate W using ozone water whose pH is adjusted with ammonia as the cleaning liquid.

  FIG. 12 is a view for explaining the configuration of a substrate processing apparatus according to the eighth embodiment of the present invention. In FIG. 12, the same reference numerals are assigned to the portions corresponding to the configurations shown in FIGS. 6 and 11 described above. This substrate processing apparatus is a batch type substrate processing apparatus that performs a process on a plurality of substrates W at once as in the apparatus of FIG. Then, the configuration shown in FIG. 11 is combined as the cleaning liquid supply mechanism 20. Even with such a configuration, a plurality of substrates W can be collectively subjected to a treatment (substrate cleaning treatment) with a cleaning liquid made of ozone water whose pH is adjusted with ammonia.

  FIG. 13 is a view for explaining the configuration of a substrate processing apparatus according to the ninth embodiment of the present invention. In FIG. 13, the same reference numerals are assigned to portions corresponding to the configuration shown in FIG. 5 described above. This substrate processing apparatus is a single-wafer type substrate processing apparatus that processes the substrates W one by one, similar to the apparatus of FIG. 5, and the configuration of the cleaning liquid supply mechanism 20 is different from the apparatus of FIG. In this embodiment, the second mixing unit 22 is omitted, and the mixing unit 21 mixes ozone water, ammonia water, and deionized water. The ozone water pipe 25 connects the ozone water supply source 36 and the mixing unit 21, and a flow rate adjusting valve 37 and an opening / closing valve 38 are interposed in the middle thereof. The mixing unit 21 is configured to inject ammonia water from the ammonia water pipe 24 and ozone water from the ozone water pipe 25 into the flow path through which the deionized water from the deionized water pipe 23 flows. Yes. In this way, the ozone water whose pH is adjusted with the ammonia water is supplied to the treatment liquid pipe 16. The processing liquid pipe 16 is connected to the mixing unit 21.

The flow rate adjustment valve 27 adjusts the flow rate of deionized water to 1550 milliliters / minute, for example. The flow rate adjusting valve 32 adjusts the flow rate of ammonia water to 70 ml / min, for example. For example, the flow rate adjustment valve 37 adjusts the flow rate of ozone water to 180 ml / min. The oxidant concentration of ozone water supplied from the ozone water pipe 25 may be 10 ppm. In this case, finally, 1 ppm ozone water mixed with ammonia water is supplied from the processing liquid pipe 16 to the processing liquid nozzle 13 at a flow rate of 1800 ml / min, and is supplied to the surface of the substrate W as a cleaning liquid. . The cleaning liquid in this case is O ₃ / NH ₄ OH mixed with aqueous ammonia at a ratio of 1730: 70. When the ammonia water concentration supplied by the ammonia water supply source 31 is 8.97 wt%, the ammonia concentration in the cleaning liquid is 0.34 wt%.

With such a configuration, it is possible to perform a cleaning process on the substrate W using ozone water whose pH is adjusted with ammonia as a cleaning liquid.
FIG. 14 is a view for explaining the structure of a substrate processing apparatus according to the tenth embodiment of the present invention. In FIG. 14, the same reference numerals are assigned to the portions corresponding to the configurations shown in FIGS. 6 and 13 described above. This substrate processing apparatus is a batch type substrate processing apparatus that performs a process on a plurality of substrates W at once as in the apparatus of FIG. Then, the configuration shown in FIG. 13 is combined as the cleaning liquid supply mechanism 20. Even with such a configuration, a plurality of substrates W can be collectively subjected to a treatment (substrate cleaning treatment) with a cleaning liquid made of ozone water whose pH is adjusted with ammonia.

  Although specific embodiments of the present invention have been described above, the present invention can also be implemented in other forms. For example, ozone water whose pH is adjusted with an alkaline substance (such as ammonia) may be generated by mixing an alkaline aqueous solution and ozone water in a preparation tank. The ozone water whose pH is adjusted with an alkaline substance (ammonia water) can also be generated by supplying an alkali gas such as ammonia gas into a water tank filled with ozone water. Furthermore, ozone water whose pH is adjusted with an alkaline substance (ammonia or the like) can also be generated by supplying ozone gas to a water tank filled with an alkaline aqueous solution such as alkaline water.

  In addition, various design changes can be made within the scope of matters described in the claims.

DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 SiGe buffer layer 3 Germanium layer 4 STI structure 5 Gate structure 6 High-k metal layer 7 Gate metal layer 8 Spacer 10 Process chamber 11 Process cup 12 Spin chuck 13 Process liquid nozzle 14 Rotating shaft 15 Rotation drive mechanism 16 Process Liquid piping 17 Treatment tank 18 Substrate holding mechanism 20 Cleaning liquid supply mechanism 21 First mixing unit 22 Second mixing unit 23 Deionized water piping 24 Ammonia water piping 25 Ozone water piping 26 Deionized water supply source 27 Flow rate adjustment valve (DIW)
28 On-off valve (DIW)
31 Ammonia water supply source 32 Flow control valve (ammonia water)
33 On-off valve (ammonia water)
35 Ammonia water supply pipe 36 Ozone water supply source 37 Flow control valve (ozone water)
38 On-off valve (ozone water)
39 Ozone water supply pipe 40 Gas dissolution unit 41 Ozone gas pipe 42 Ozone gas supply source 43 Flow control valve (ozone gas)
44 On-off valve (ozone gas)
46 Gas dissolution unit 47 Ammonia gas piping 48 Ammonia gas supply source 49 Flow control valve (ammonia gas)
50 On-off valve (ammonia gas)
W substrate

Claims (14)

A substrate cleaning method for supplying a cleaning liquid to a substrate surface where a germanium layer is exposed,
A substrate cleaning method using ozone water having a pH adjusted to a value greater than 7 by adding an alkaline substance as the cleaning liquid.   The substrate cleaning method according to claim 1, wherein the alkaline substance includes one or more selected from the group consisting of ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide (TMAH), and choline.   The substrate cleaning method according to claim 1, wherein an oxidant concentration of the cleaning liquid is 0.5 ppm to 20 ppm.   A cleaning solution for cleaning a substrate surface from which a germanium layer is exposed, the substrate cleaning solution comprising ozone water having a pH adjusted to a value greater than 7 by addition of an alkaline substance.   The substrate cleaning liquid according to claim 4, wherein the alkaline substance includes one or more selected from the group consisting of ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide (TMAH), and choline.   The substrate cleaning solution according to claim 4 or 5, wherein the oxidizing agent concentration is 0.5 ppm to 20 ppm. Substrate holding means for holding a substrate having a surface with an exposed germanium layer;
A substrate processing apparatus, comprising: a cleaning liquid supply unit configured to supply a cleaning liquid made of ozone water having a pH adjusted to a value greater than 7 by adding an alkaline substance to the surface of the substrate held by the substrate holding unit.   The substrate processing apparatus according to claim 7, wherein the alkaline substance includes one or more selected from the group consisting of ammonia, potassium hydroxide, sodium hydroxide, tetramethylammonium hydroxide (TMAH), and choline.   The substrate processing apparatus according to claim 7 or 8, wherein an oxidizing agent concentration of the cleaning liquid is 0.5 ppm to 20 ppm.   The substrate processing apparatus according to claim 7, wherein the cleaning liquid supply unit includes a mixing unit that prepares the cleaning liquid.   The blending means is an alkaline aqueous solution supply pipe for circulating an alkaline aqueous solution, a mixing unit provided in the middle of the alkaline aqueous solution supply pipe, and ozone that is coupled to the mixing unit and allows ozone water to flow toward the mixing unit. The substrate processing apparatus as described in any one of Claims 7-10 containing water piping.   The blending means is connected to an alkaline aqueous solution supply pipe for circulating an alkaline aqueous solution, a gas dissolving unit provided in the middle of the alkaline aqueous solution supply pipe, and the gas dissolving unit, and distributes ozone gas toward the gas dissolving unit. The substrate processing apparatus as described in any one of Claims 7-10 containing the ozone gas piping to be made.   The blending means is an ozone water supply pipe for circulating ozone water, a mixing unit provided in the middle of the ozone water supply pipe, and an alkali that is connected to the mixing unit and flows an alkaline aqueous solution toward the mixing unit. The substrate processing apparatus as described in any one of Claims 7-10 containing aqueous solution piping.   The blending means is coupled to an ozone water supply pipe through which ozone water is circulated, a gas dissolution unit provided in the middle of the ozone water supply pipe, and the gas dissolution unit, and the alkali gas is supplied to the gas dissolution unit. The substrate processing apparatus as described in any one of Claims 7-10 containing the alkali gas piping to distribute | circulate.

Images