TWI837412B - Substrate processing method - Google Patents

Abstract

The subject of the present invention is to provide a substrate processing method that can enhance the effect of ozone on a substrate. The substrate processing method of the present invention comprises: a step of holding a substrate (WF) having a first surface (S1) and a second surface (S2) opposite to the first surface (S1); a step of supplying a processing liquid mixed with bubbles of a particle size of 50 nm or less containing ozone gas to the second surface (S2) of the wafer (WF); and a step of heating the processing liquid at a point of use for processing the substrate (WF).

Description

Substrate processing method

The present invention relates to a substrate processing method, and more particularly to a substrate processing method using ozone gas.

After the step of using a photoresist film on a wafer (substrate), the photoresist film is usually removed from the substrate. In particular, since the photoresist film used as an implantation mask for the ion implantation step is not easy to remove, a cleaning solution with a stronger effect is generally used. As a cleaning solution with a stronger effect, sulfuric acid/hydrogen peroxide mixure (SPM) has been widely known in the past. However, due to the heavy burden of waste liquid treatment, substrate processing methods that do not use SPM have been required in recent years.

According to Japanese Patent Publication No. 2008-153605, a substrate cleaning method is disclosed in which ozone water generated by a gas-liquid mixing method without addition is used to clean a substrate. Here, the particle size R of the ozone bubbles contained in the ozone water is 0＜R≦50nm. In addition, it is disclosed that the generated ozone water is heated before being supplied to the processing tank. As a heating temperature, a range of 30℃ to 80℃ is exemplified. According to the above-mentioned publication, the following issues 1 and 2 are advocated.

First, since the ozone bubbles have a particle size of less than 50nm, the buoyancy they receive from the ozone water is extremely small, so it is difficult for the ozone bubbles to rise to the water surface. In other words, they will be stably retained in the ozone water. Stably retained ozone bubbles will rarely be degassed due to the impact when the ozone water collides with the substrate, etc. This can effectively suppress ozone degassing.

Second, the temperature of the ozone water is raised to an appropriate temperature for cleaning, so that cleaning can be performed more efficiently. The appropriate temperature may be affected by the nature of the object to be cleaned, whether it is partial cleaning or full cleaning, the length of cleaning time, and other environmental factors, but generally a higher temperature is better. On the other hand, since ozone is more easily dissolved in water at a lower temperature, it is also a fact that if the ozone water is heated, it is easy to degas or thermally decompose. In contrast, since the particle size of the ozone bubbles contained in the ozone water is less than 50nm, even if it expands due to heating, the buoyancy it receives is still very small. Therefore, the ozone bubbles will remain in the ozone water and will not be easily degassed. It is speculated that the temperature of ozone water can rise to around 80°C because the particle size of the ozone bubbles is small enough.

As described above, according to the above-mentioned publication, it is claimed that sufficient cleaning effect can be obtained by preventing degassing easily. [Prior technical literature] [Patent literature]

[Patent Document 1] Japanese Patent Publication No. 2008-153605

(Invent the problem you want to solve)

According to the review of the inventors of this case, in the technology described in the above-mentioned gazette, when the ozone water used as the treatment liquid is not heated, the effect on the substrate is often insufficient. Although the effect will be enhanced by increasing the ozone concentration, the upper limit of the ozone concentration in the ozone water is usually about 80ppm. Therefore, in order to promote the chemical action of ozone, it is desirable to heat it to a certain temperature. In the technology of the above-mentioned gazette, the ozone water used as the treatment liquid is heated before the treatment liquid is supplied to the treatment tank. According to the review of the inventors of this case, in this case, it is difficult for the ozone bubbles to maintain a dispersed state in a high concentration in the treatment liquid before reaching the point of use (POU: Point of Use) of the treatment liquid. As a result, the unique effect that can be obtained by mixing tiny ozone bubbles will be reduced. Therefore, the treatment effect using ozone will be weakened.

This invention is completed to solve the above-mentioned problem, and its purpose is to provide a substrate processing method that can enhance the effect of ozone on the substrate. (Technical means to solve the problem)

The first aspect is a substrate processing method, which comprises: a step of holding a substrate having a first surface and a second surface opposite to the first surface; a step of supplying a processing liquid mixed with bubbles of a particle size of 50 nm or less containing ozone gas to the second surface of the substrate; and a step of heating the processing liquid at a point of use for processing the substrate. In addition, in addition to bubbles of a particle size of 50 nm or less, bubbles of a particle size of more than 50 nm may be mixed into the processing liquid.

The second aspect is that in the substrate processing method of the first aspect, the step of holding the substrate is performed with the second surface of the substrate facing downward.

According to a third aspect, in the substrate processing method of the first or second aspect, the step of heating the processing liquid includes the step of heating the substrate from the first surface.

According to a fourth aspect, in the substrate processing method of the first or second aspect, the step of heating the processing liquid includes the step of heating the substrate from the second surface.

According to a fifth aspect, in the substrate processing method of the first or second aspect, the step of heating the processing liquid includes the step of heating the substrate from the first surface and the second surface simultaneously.

A sixth aspect is a substrate processing method according to any one of the first to fifth aspects, wherein the step of supplying the processing liquid includes the step of ejecting the processing liquid toward the second surface of the substrate.

A seventh aspect is a substrate processing method according to any one of the first to fifth aspects, wherein the step of supplying a processing liquid includes a step of immersing the second surface of the substrate in the processing liquid stored in a processing tank.

The eighth aspect is a step of immersing the second surface of the substrate in the substrate processing method of the seventh aspect, in which the first surface of the substrate is located above the liquid level of the processing liquid.

A ninth aspect is a step of immersing the second surface of the substrate in the substrate processing method of the seventh or eighth aspect, comprising the step of sealing a processing tank storing the processing solution.

A tenth aspect is the substrate processing method of any one of the first to ninth aspects, wherein the processing liquid comprises water.

The eleventh aspect is the substrate processing method according to the tenth aspect, wherein the processing liquid includes at least one of ammonia and hydrogen peroxide.

The twelfth aspect is the substrate processing method of any one of the first to ninth aspects, further comprising: a step of generating a processing liquid. The step of generating a processing liquid includes a step of mixing bubbles containing ozone gas with a particle size of 50 nm or less into an aqueous solution containing ozone water.

The 13th aspect is a substrate processing method of the 12th aspect, wherein the aqueous solution contains at least one of ammonia and hydrogen peroxide. (Compared with the effect of the prior art)

According to the first aspect, since the treatment liquid is heated at the use point, the temperature of the treatment liquid can be suppressed to a lower level just before reaching the use point. Thereby, the ozone bubbles can be easily maintained in a state of being dispersed at a high concentration in the treatment liquid before reaching the use point. Therefore, the ozone bubbles can be supplied to the second surface of the substrate at a high concentration. Then, the bubble treatment liquid is heated and expanded at the use point. Thereby, since the surface area of the bubbles becomes larger, it becomes easier for the bubbles to contact the second surface of the substrate. A thin film of the treatment liquid is formed between the bubbles contacting the second surface of the substrate and the second surface of the substrate. The thin film of the treatment liquid has a higher ozone concentration due to being adjacent to the bubbles. In addition, due to the above-mentioned heating, the ozone of the thin film has a higher temperature. Therefore, the ozone in the thin film of the treatment liquid has both a high concentration and a high temperature, so the second surface of the substrate in contact with the thin film will be more strongly affected by the ozone. Thereby, the effect of ozone on the substrate can be strengthened.

According to the second aspect, the processing liquid is supplied to the second side of the main substrate facing downward. Thereby, the second side of the substrate is located above the supplied processing liquid. Then, as the processing liquid is heated, tiny bubbles expand. The expanded bubbles easily float in the processing liquid. In other words, the bubbles easily move toward the second side of the substrate. Thereby, the bubbles can more easily contact the second side of the substrate. Therefore, the effect of ozone on the substrate can be further enhanced.

According to the third aspect, the step of heating the processing liquid includes the step of heating the substrate from the first surface. Thus, the adverse effects of heating are unlikely to affect the second surface.

According to the fourth aspect, the step of heating the processing liquid includes the step of heating the substrate from the second surface. Thereby, the second surface, which is the surface to be processed, can be preferentially heated between the first surface and the second surface.

According to the fifth aspect, the step of heating the processing liquid includes the step of heating the substrate from the first surface and the second surface simultaneously. Thereby, the second surface as the surface to be processed can be easily and sufficiently heated.

According to the sixth aspect, the step of supplying the processing liquid includes the step of discharging the processing liquid toward the second surface of the substrate. Thus, the processing liquid can be continuously supplied toward the second surface of the substrate. Therefore, the effect of ozone can be prevented from being weakened due to deactivation.

According to the seventh aspect, the step of supplying the treatment liquid includes the step of immersing the second surface of the substrate in the treatment liquid stored in the treatment tank. Thereby, the time for the bubbles in the treatment liquid to expand and move toward the second surface of the substrate can be ensured longer.

According to the eighth aspect, the step of immersing the second surface of the substrate is performed in such a way that the first surface of the substrate is located above the liquid level of the treatment liquid. Thus, the height of the second surface of the substrate is close to the liquid level where the density of bubbles tends to increase. Therefore, the bubbles can more easily contact the second surface of the substrate. Therefore, the effect of ozone on the substrate can be further enhanced.

According to the ninth aspect, the step of immersing the second surface of the substrate includes the step of sealing the treatment tank storing the treatment solution. Thus, ozone will not easily escape from the treatment solution. Therefore, the effect of ozone on the substrate can be further enhanced.

According to the tenth aspect, the processing liquid includes water, thereby allowing the ozone water to act on the substrate.

According to the eleventh aspect, the processing liquid includes at least one of ammonia and hydrogen peroxide. This can promote the processing of the substrate.

According to the twelfth aspect, the step of generating the treatment solution includes the step of mixing bubbles with a particle size of 50 nm or less containing ozone gas into the aqueous solution containing ozone water. Thereby, the effect of ozone on the substrate can be further enhanced.

According to the 13th aspect, the aqueous solution includes at least one of ammonia and hydrogen peroxide. This can promote the processing of the substrate.

In the following, the embodiments of the present invention are described according to the drawings. In the following drawings, the same or corresponding parts are marked with the same element symbols and their descriptions are not repeated.

(Implementation Form 1) Figure 1 is a block diagram schematically showing the structure of the substrate processing system in this implementation form 1. The substrate processing system has an indexing machine 310, a turning mechanism 320, a central robot 330 (transport mechanism), a processing device 101 (substrate processing device), a processing device 201, and a control unit 90 (controller).

The indexer 310 is a mechanism that can deliver and receive wafers (substrates). The flip mechanism 320 is disposed between the indexer 310 and the central robot 330 to flip the wafers passing therebetween. The central robot 330 transfers wafers between the flip mechanism 320 and each of the processing apparatuses 101 and 201.

The processing device 101 is a monolithic device that can be used to remove organic matter attached to a wafer. The organic matter is typically a used photoresist film. The photoresist film is used, for example, as an implantation mask for an ion implantation step.

The processing device 201 may be the same as or different from the processing device 101. Furthermore, the number of processing devices included in the substrate processing system is arbitrary.

FIG2 is a block diagram schematically showing the structure of the control unit 90 (FIG1). The control unit 90 can be formed by a general computer having an electrical circuit. Specifically, the control unit 90 has a CPU (Central Processing Unit) 91, a ROM (Read Only Memory) 92, a RAM (Random Access Memory) 93, a storage device 94, an input unit 96, a display unit 97, a communication unit 98, and a bus 95 connecting them to each other.

ROM 92 stores basic programs. RAM 93 is used as a work area when CPU 91 performs predetermined processing. Storage device 94 is composed of a non-volatile storage device such as a flash memory or a hard disk device. Input unit 96 is composed of various switches or touch panels, etc., and receives input setting instructions such as processing recipes from the operator. Display unit 97 is composed of, for example, a liquid crystal display device and a lamp, and displays various information under the control of CPU 91. Communication unit 98 has a data communication function via LAN (Local Area Network) and the like. Storage device 94 pre-sets a plurality of modes for controlling each device constituting the substrate processing system (Figure 1). One of the above-mentioned multiple modes is selected by the CPU 91 executing the processing program 94P, so that each device is controlled by the mode. In addition, the processing program 94P can also be stored in a recording medium. If the recording medium is used, the processing program 94P can be installed in the control unit 90. In addition, part or all of the functions executed by the control unit 90 must be realized by software, and can also be realized by hardware such as a dedicated logic circuit.

FIG3 is a cross-sectional view schematically showing the structure of the processing device 101. The processing device 101 has a processing liquid supply unit 121, a heating unit 141, and a holding unit 151. In addition to the processing device 101, the figure also shows a wafer WF (substrate) to be processed by the processing device 101. The wafer WF has a back side S1 (first side) and a processing side S2 (second side opposite to the first side).

The treatment liquid supply unit 121 has a deionized water (DIW: De-Ionized Water) source 21, an ozone gas source 22, a bubble generator 23, and a treatment liquid nozzle 31. The bubble generator 23 mixes ozone gas with deionized water. Thereby, bubbles with a particle size of 50nm or less containing ozone gas are mixed into the deionized water. Hereinafter, bubbles with such a particle size will also be referred to as "micro bubbles". The particle size distribution of micro bubbles typically includes particles with a particle size of 1nm or more, for example, particularly including many particles of around 10nm. Deionized water mixed with micro bubbles containing ozone gas will be used as a treatment liquid in the treatment device 101. Furthermore, in addition to micro bubbles, the treatment liquid may also be mixed with bubbles with a particle size exceeding 50nm. The processing liquid nozzle 31 has a front end facing upward, and discharges the processing liquid toward the processing surface S2 of the wafer WF as indicated by an arrow D2.

The heating unit 141 includes a lamp heater 41. The lamp heater 41 radiates light LT toward the back surface S1 of the wafer WF. The back surface S1 is heated by absorbing the light LT. Therefore, the light LT preferably includes light of a wavelength that is easily absorbed by the wafer WF. The lamp heater 41 preferably includes a light emitting diode (LED).

Furthermore, the heating unit 141 may also include a machine arm 56 for holding the lamp heater 41, a rotation shaft 57, and a rotation angle adjuster 58. The rotation angle adjuster 58, which is composed of an actuator, adjusts the rotation angle of the rotation shaft 57 as indicated by the arrow Ag. The machine arm 56 extends radially from the rotation shaft 57. By the operation of the rotation angle adjuster 58, a position on the back surface S1 that is strongly exposed to the light LT from the lamp heater 41 is scanned. In this way, the back surface S1 can be heated more evenly.

In addition, the heating part 141 may also have a hot water source 51 and a hot water nozzle 52. The hot water nozzle 52 supplies hot water from the hot water source 51 to the back side S1. The hot water on the back side S1 can alleviate the rapid heating of the back side S1 by the light LT. Thereby, the warping of the wafer WF caused by uneven heating can be suppressed. The hot water nozzle 52 can be mounted on the machine arm 56, thereby making it easy to synchronize the displacement of the lamp heater 41 with the displacement of the hot water nozzle 52. Furthermore, cold water (unheated water) can be used instead of hot water. Alternatively, the hot water source 51 and the hot water nozzle 52 can be omitted.

The holding portion 151 includes a holding pin 11, a rotating plate 61, and a motor 65. The holding pin 11 supports the wafer WF. The rotating plate 61 supports the holding pin 11. The motor 65 rotates the rotating plate 61 as indicated by the arrow RT. With this configuration, the wafer WF can be rotated. The processing liquid ejected as indicated by the arrow D2 is spread over the entire processing surface S2 as indicated by the arrow SR due to the rotation of the wafer WF.

Furthermore, the operation of the above-mentioned components of the processing device 101 can be controlled by the control unit 90 ( FIG. 1 ).

Next, the wafer (substrate) processing method of this embodiment is described below.

Referring to step S10 (FIG. 4), the indexer 310 (FIG. 1) transfers the wafer WF toward the flip mechanism 320. When the wafer WF is transferred toward the flip mechanism 320, the processing surface S2 of the wafer WF faces upward. Referring to step S20 (FIG. 4), the wafer WF is flipped by the flip mechanism 320, and the processing surface S2 of the wafer WF faces downward. The flipped wafer WF is transferred toward the processing device 101 by the central robot 330 (FIG. 1).

Referring to step S30 (FIG. 4), the wafer WF (substrate) is held by the holding pin 11 (FIG. 3). As a result of the above-mentioned flipping, the holding is performed in a manner that the processing surface S2 of the wafer WF faces downward. Next, the wafer WF is rotated by the rotating plate 61 (FIG. 3) (arrow RT).

Referring to step S40 (FIG. 4), the processing liquid nozzle 31 ejects the processing liquid mixed with the micro bubbles containing the ozone gas toward the processing surface S2 of the wafer WF (arrow D2). Thus, the processing liquid is supplied toward the processing surface S2 of the wafer WF. The supplied processing liquid is diffused over the entire processing surface S2 as indicated by the arrow SR due to the centrifugal force.

Referring to step S50 (FIG. 4), the wafer WF is heated from the back side S1 by the heating unit 141. Specifically, the back side S1 of the wafer WF is heated by absorbing the light LT from the lamp heater 41. The processing surface S2 is heated by heat conduction from the back side S1. The processing liquid is heated on the processing surface S2 by heat conduction from the heated processing surface S2. It is preferred that the processing liquid is heated to a temperature above 40°C and below the boiling point, and it is more preferred that it is heated to a temperature close to the boiling point within the temperature range. The position on the processing surface S2 (in other words, the position directly below the processing surface S2) is the position where the processing liquid acts on the wafer WF, that is, the use point for processing the wafer WF. Therefore, the processing liquid is heated at the use point for processing the wafer WF by the above-mentioned heating. The heated processing liquid acts on the processing surface S2 to process the wafer WF. Specifically, the wafer WF is cleaned, for example, the photoresist is removed.

Referring to step S60 (FIG. 4), after the above-mentioned cleaning step, a rinsing step of the wafer WF is performed. The rinsing step can be performed by the processing device 101 (FIG. 3) or by the processing device 201 (FIG. 1). When the processing device 101 is used, the deionized water from the deionized water source 21 is directly transferred to the processing liquid nozzle 31 by the bubble generator 23 (FIG. 3) without being mixed with the ozone gas. After the rinsing step, the wafer WF is dried, for example, by spin drying. The dried wafer WF is transferred to the flip mechanism 320 by the central robot 330 (FIG. 1).

Referring to step S70 ( FIG. 4 ), the wafer WF is flipped by the flip mechanism 320 ( FIG. 1 ), and the processing surface S2 of the wafer WF faces upward again. Referring to step S80 ( FIG. 4 ), the indexer 310 ( FIG. 1 ) receives the wafer WF from the flip mechanism 320 .

Thereby, the processing of the wafer WF is completed.

According to the present embodiment, since the processing liquid is heated at the point of use, the temperature of the processing liquid can be kept relatively low until it is about to reach the point of use. Thereby, it is easy to maintain the state in which the micro bubbles of ozone are dispersed at a high concentration in the processing liquid until it reaches the point of use. Therefore, the micro bubbles of ozone can be supplied to the processing surface S2 of the wafer WF at a high concentration. Then, the bubbles will expand due to the heating of the processing liquid at the point of use. Thereby, since the surface area of the bubbles will increase, the bubbles will easily contact the processing surface S2 of the wafer WF. A thin film of the processing liquid is formed between the bubbles contacting the processing surface S2 of the wafer WF and the processing surface S2 of the wafer WF. The thin film of the processing liquid has a higher ozone concentration due to being adjacent to the bubbles. In addition, through the above-mentioned heating, the ozone in the film has a higher temperature. Since the ozone in the film of the processing liquid has both a higher concentration and a higher temperature, the processing surface S2 of the wafer WF in contact with the film is more strongly affected by the ozone. In this way, the effect of ozone on the wafer WF can be strengthened.

The processing liquid is supplied to the processing surface S2 of the wafer WF facing downward. Thereby, the processing surface S2 of the wafer WF is located above the supplied processing liquid. Then, the tiny bubbles expand due to the heating of the processing liquid. The expanded bubbles easily float in the processing liquid. In other words, the bubbles easily move toward the processing surface S2 of the wafer WF. Thereby, the bubbles can more easily contact the processing surface S2 of the wafer WF. Therefore, the effect of ozone on the wafer WF can be further enhanced.

The processing liquid is heated by heating the wafer WF from the back side S1. Thus, the adverse effects of heating are unlikely to reach the processing surface S2. Specifically, the light LT (FIG. 3) from the lamp heater 41 is shielded by the wafer WF and does not substantially reach the processing surface S2. Thus, the photoresist on the processing surface S2 is prevented from being hardened due to the photosensitivity of the light LT. Therefore, the photoresist is prevented from being difficult to remove due to hardening. Therefore, the effect of wafer processing can be improved.

The supply of the processing liquid is performed by discharging the processing liquid toward the processing surface S2 of the wafer WF. In this way, the processing liquid can be continuously supplied to the processing surface S2 of the wafer WF again. Therefore, the situation where the effect of ozone is weakened due to deactivation can be avoided.

The processing liquid includes water, thereby allowing the ozone water to act on the wafer WF.

(Variation of Implementation Form 1) The method of heating the wafer WF is not limited to the above method. The wafer WF (FIG. 3) can also be heated from the processing surface S2 instead of the back surface S1. In this way, the processing surface S2, which is the surface to be processed, can be heated preferentially between the back surface S1 and the processing surface S2. The heating from the processing surface S2 can be performed, for example, using a heater 43 (see FIG. 6 described later). Alternatively, the wafer WF can also be heated from the back surface S1 and the processing surface S2 simultaneously. In this way, the processing surface S2 can be easily and sufficiently heated.

The water in the processing liquid may contain at least one of ammonia and hydrogen peroxide, or both of them, thereby promoting the processing of the wafer WF.

The processing liquid can also be generated by pre-mixing micro bubbles containing ozone gas into an aqueous solution containing ozone water. Therefore, it is sufficient to use an ozone water source to replace the deionized water source 21. In this way, the effect of ozone on the wafer WF can be further enhanced. In addition, the above-mentioned aqueous solution can contain at least one of ammonia and hydrogen peroxide, or both. In this way, the processing of the wafer WF can be promoted.

(Implementation Form 2) Figure 5 is a cross-sectional view schematically showing the structure of the processing device 102 (substrate processing device) in this implementation form 2. The processing device 102 can be used as a substitute for the processing device 101 (Figure 3: Implementation Form 1) in the substrate processing system (Figure 1). The processing device 102 has a processing liquid supply unit 122, a heater 42 as a heating unit, and a holding ring 12 as a holding unit for the wafer WF.

The treatment liquid supply unit 122 has a treatment liquid introduction pipe 32 instead of the treatment liquid nozzle 31 (FIG. 3: Embodiment 1), and further has a valve 24 and a treatment tank 62. The valve 24 is arranged between the treatment liquid introduction pipe 32 and the bubble generator 23. When the valve 24 is in an open state, the treatment liquid introduction pipe 32 will introduce the treatment liquid into the treatment tank 62 as shown by the arrow IR. If the valve 24 is closed, the introduction of the treatment liquid from the treatment liquid introduction pipe 32 will be stopped.

After the processing liquid is fully introduced, a region filled with the processing liquid is formed directly below the processing surface S2 of the wafer WF in a manner that contacts the processing surface S2. With respect to the vertical direction, the region is sandwiched between the components of the processing device 102 (e.g., the processing tank 62 and the processing liquid introduction pipe 32) and the wafer WF, and the processing liquid will not leak out, in other words, it is in a liquid-tight state. In particular, if the valve 24 is set to a closed state, the region is in a state with respect to the vertical direction where the processing liquid will neither leak out nor be introduced.

The heater 42 as a heating unit may be, for example, a heat generating heater built into the processing tank 62. The heater 42 faces the processing surface S2 of the wafer WF. Therefore, the wafer WF is heated from the processing surface S2 by the heater 42. The holding ring 12 as a holding unit supports the wafer WF in the processing tank 62.

Next, the wafer (substrate) processing method of this embodiment will be described below, mainly focusing on the differences from embodiment 1.

Referring to step S30 ( FIG. 4 ), the holding ring 12 ( FIG. 5 ) holds the wafer WF. The holding is performed in such a manner that the processing surface S2 of the wafer WF faces downward. This embodiment is different from the embodiment 1 in that the wafer WF is not rotated.

Referring to step S40 (FIG. 4), the processing liquid introduction pipe 32 introduces the processing liquid LP mixed with micro bubbles containing ozone gas into the processing tank 62 (arrow IR). Thereby, the processing liquid LP is stored in the processing tank 62. As the processing liquid LP is introduced, the liquid level LS rises and eventually reaches the processing surface S2 of the wafer WF. In other words, the processing surface S2 is immersed in the processing liquid LP stored in the processing tank 62.

Referring to step S50 (FIG. 4), the wafer WF is heated from the processing surface S2 by the heater 42 serving as a heating unit. Specifically, the processing surface S2 of the wafer WF is heated by the heat release from the heater 42. Furthermore, the processing liquid on the processing surface S2 is heated by the heat release from the heater 42. The position on the processing surface S2 (in other words, the position directly below the processing surface S2) is the position where the processing liquid LP acts on the wafer WF, that is, the point of use for processing the wafer WF. Therefore, by the above-mentioned heating, the processing liquid LP is heated at the point of use for processing the wafer WF. The processing of the wafer WF is performed by the heated processing liquid LP acting on the processing surface S2. Specifically, the wafer WF is cleaned (for example, photoresist removal).

The above-mentioned immersion of the processing surface S2 of the wafer WF is preferably performed in a manner that the back surface S1 is located above the liquid level LS of the processing liquid LP. Such a positional relationship can be achieved by continuously introducing the processing liquid into the processing tank 62 as shown by the arrow IR during immersion, while allowing the processing liquid LP to overflow at the height between the processing surface S2 and the back surface S1 as shown by the arrow OF.

Furthermore, regarding the configurations and methods other than those described above, since they are substantially the same as those of the above-described embodiment 1 or its variations, the same or corresponding components are designated by the same component symbols and repeated descriptions are omitted.

By means of this embodiment, substantially the same effect as that of the aforementioned embodiment 1 can be obtained. Furthermore, in this embodiment, unlike the aforementioned embodiment 1, the processing surface S2 of the wafer WF is immersed in the processing liquid LP stored in the processing tank 62. Thereby, the flow of the processing liquid facing the processing surface S2 can be set to be slow or substantially stopped. Therefore, the time for the bubbles that expand due to the heating at the use point to float can be ensured longer. In other words, the time for the bubbles to move toward the processing surface S2 of the wafer WF can be ensured longer. Thereby, the bubbles can more easily contact the processing surface S2 of the wafer WF. Therefore, the effect of ozone on the wafer WF can be further enhanced.

The processing liquid LP is heated by heating the wafer WF from the processing surface S2. Thus, the processing surface S2, which is the surface to be processed, can be heated preferentially between the back surface S1 and the processing surface S2.

When the immersion of the processing surface S2 of the wafer WF is performed in a manner that the back surface S1 of the wafer WF is located above the liquid level of the processing liquid, the height of the processing surface S2 will be close to the liquid level LS where the density of bubbles tends to increase. Therefore, the bubbles will be more likely to contact the processing surface S2 of the wafer WF. Therefore, the effect of ozone on the wafer WF can be further enhanced.

(Variation of Implementation Form 2) The method of heating the wafer WF is not limited to the above method. The wafer WF can also be heated from the back side S1 instead of the processing surface S2. The heating from the back side S1 can be performed, for example, using the heating unit 141 (Figure 3: Implementation Form 1). Alternatively, the wafer WF can also be heated from the back side S1 and the processing surface S2 at the same time. Thereby, the processing surface S2 can be easily and sufficiently heated.

When the processing surface S2 of the wafer WF is immersed, the processing tank 62 storing the processing liquid LP can also be sealed. Thereby, ozone is not easy to escape from the processing liquid LP. Therefore, the effect of ozone on the wafer WF can be further enhanced. The above-mentioned sealing can be obtained, for example, by not designing a gap GP between the edge of the processing tank 62 and the retaining ring 12. For this purpose, a sealing component such as an O-ring can also be provided between the edge of the processing tank 62 and the retaining ring 12.

(Implementation Form 3) Figure 6 is a cross-sectional view schematically showing the structure of the processing device 103 (substrate processing device) in this implementation form 3. The processing device 103 can be used as a substitute for the processing device 101 (Figure 3: Implementation Form 1) in the substrate processing system (Figure 1), and in this case, the flip mechanism 320 is not required.

The processing device 103 includes a processing liquid supply unit 123, a heater 43 as a heating unit, and a holding unit 153. The processing liquid supply unit 123 includes a processing liquid nozzle 33 instead of the processing liquid nozzle 31 (FIG. 3: Embodiment 1). The processing liquid nozzle 33 has a front end facing downward, and discharges the processing liquid toward the processing surface S2 of the wafer WF as indicated by an arrow D2.

The heater 43 as a heating unit radiates heat toward the back surface S1 of the wafer WF as indicated by the arrow RD. The back surface S1 is heated thereby. By making the size of the heater 43 large enough, even if the scanning operation of the heater as described in the first embodiment is not performed, a certain degree of heating uniformity can be ensured.

The holding portion 153 includes a holding pin 11, a rotating ring 63, and a motor 65. The rotating ring 63 supports the holding pin 11. The motor 65 rotates the rotating ring 63. With this configuration, the wafer WF can be rotated as indicated by the arrow RT. The processing liquid ejected as indicated by the arrow D2 is spread over the entire processing surface S2 as indicated by the arrow SR due to the rotation of the wafer WF by the centrifugal force.

In the wafer (substrate) processing method using the processing apparatus 103, the wafer WF is held with the processing surface S2 facing upward. When the processing liquid is heated, the wafer WF is heated from the back surface S1.

Furthermore, regarding the configurations and methods other than those described above, since they are substantially the same as those of the above-described embodiment 1 or its variations, the same or corresponding components are designated by the same component symbols and repeated descriptions are omitted.

According to the present embodiment, similar to the embodiment 1, since the processing liquid is heated at the use point, the temperature of the processing liquid can be suppressed to a lower level just before reaching the use point. Thereby, it is easy to maintain the ozone bubbles dispersed in the processing liquid at a high concentration until the use point. Therefore, the ozone bubbles can be supplied to the processing surface S2 of the wafer WF at a high concentration. Then, the bubbles will expand due to the heating of the processing liquid at the use point. Thereby, since the surface area of the bubbles will increase, the bubbles will easily contact the processing surface S2 of the wafer WF. A thin film of the processing liquid is formed between the bubbles contacting the processing surface S2 of the wafer WF and the processing surface S2 of the wafer WF. This thin film of the processing liquid has a higher ozone concentration due to being adjacent to the bubbles. In addition, through the above-mentioned heating, the ozone in the film has a higher temperature. Therefore, the ozone in the film of the processing liquid has both a higher concentration and a higher temperature, so the processing surface S2 of the wafer WF in contact with the film will be more strongly affected by the ozone. In this way, the effect of ozone on the wafer WF can be strengthened.

(Variation of Implementation Form 3) The method of heating the wafer WF is not limited to the above method. The wafer WF may be heated from the processing surface S2 instead of the back surface S1. In this way, the processing surface S2, which is the surface to be processed, can be heated preferentially between the back surface S1 and the processing surface S2. Alternatively, the wafer WF may be heated from the back surface S1 and the processing surface S2 simultaneously. In this way, the processing surface S2 can be easily and sufficiently heated.

Although the present invention has been described in detail, the above description is only for illustration in all aspects, and the present invention is not limited thereto. Countless variations that are not illustrated should be understood as being conceivable without departing from the scope of the present invention. The various structures described in the above embodiments and various variations can be appropriately combined or omitted as long as they do not contradict each other.

11: Retaining pin 12: Retaining ring 21: Deionized water source 22: Ozone gas source 23: Bubble generator 24: Valve 31,33: Processing liquid nozzle 32: Processing liquid inlet pipe 41: Lamp heater 42,43: Heater 51: Hot water source 52: Hot water nozzle 56: Machine arm 57: Rotating shaft 58: Rotation angle adjuster 61: Rotating plate 62: Processing tank 63: Rotating ring 65: Motor 90: Control unit 91: CPU 92: ROM 93: RAM 94: Storage Storage device 94P: Processing program 95: Bus line 96: Input unit 97: Display unit 98: Communication unit 101~103,201: Processing device (substrate processing device) 121~123: Processing liquid supply unit 141: Heating unit 151,153: Holding unit 310: Indexing machine 320: Flip mechanism 330: Central robot GP: Gap LP: Processing liquid LS: Liquid level LT: Light S1: Back side (1st side) S2: Processing side (2nd side) WF: Wafer (substrate)

FIG. 1 is a block diagram schematically showing the structure of the substrate processing system in the first embodiment of the present invention. FIG. 2 is a block diagram schematically showing the structure of the control unit included in the substrate processing system of FIG. 1. FIG. 3 is a cross-sectional view schematically showing the structure of the substrate processing device in the first embodiment of the present invention. FIG. 4 is a flow chart schematically showing the substrate processing method in the first embodiment of the present invention. FIG. 5 is a cross-sectional view schematically showing the structure of the substrate processing device in the second embodiment of the present invention. FIG. 6 is a cross-sectional view schematically showing the structure of the substrate processing device in the third embodiment of the present invention.

11: Retaining pin

21: Deionized water source

22: Ozone gas source

23: Bubble generator

31: Treatment fluid nozzle

41: Lamp heater

51:Warm water source

52: Warm water nozzle

56: Robot arm

57: Rotation axis

58: Rotation angle adjuster

61: Rotating plate

65: Motor

121: Treatment fluid supply unit

141: Heating unit

151:Maintenance Department

LT: Light

S1: Back side (1st side)

S2: Processing surface (2nd side)

WF: Wafer (substrate)

Claims (15)

A substrate processing method comprises: a step of holding a substrate having a first surface and a second surface opposite to the first surface; a step of supplying a processing liquid mixed with bubbles of a particle size of 50 nm or less containing ozone gas to the second surface of the substrate; and a step of heating the processing liquid by applying heat to the processing liquid at a point of use where the processing liquid acts on the substrate for processing the substrate. As in claim 1, the substrate processing method, wherein the step of maintaining the substrate is performed in a manner such that the second surface of the substrate faces downward. A substrate processing method as claimed in claim 1 or 2, wherein the step of heating the processing liquid includes the step of heating the substrate from the first surface. A substrate processing method as claimed in claim 1 or 2, wherein the step of heating the processing liquid includes the step of heating the substrate from the second surface. A substrate processing method as claimed in claim 1 or 2, wherein the step of heating the processing liquid includes the step of heating the substrate from the first surface and the second surface simultaneously. A substrate processing method as claimed in claim 1 or 2, wherein the step of supplying the processing liquid includes the step of discharging the processing liquid toward the second surface of the substrate. The substrate processing method of claim 1 or 2, wherein the step of supplying the processing liquid includes the step of immersing the second surface of the substrate in the processing liquid stored in the processing tank. The substrate processing method of claim 7, wherein the step of immersing the second surface of the substrate is performed in a manner such that the first surface of the substrate is located above the liquid level of the processing liquid. In the substrate processing method of claim 7, the step of immersing the second surface of the substrate includes the step of sealing the processing tank storing the processing liquid. A substrate processing method as claimed in claim 1 or 2, wherein the processing liquid contains water. As in claim 10, the substrate processing method, wherein the processing liquid contains at least one of ammonia and hydrogen peroxide. The substrate processing method of claim 1 or 2 further comprises: a step of generating the above-mentioned processing liquid; and the step of generating the above-mentioned processing liquid includes a step of mixing bubbles containing ozone gas with a particle size of less than 50nm into an aqueous solution containing ozone water. As in claim 12, the substrate processing method, wherein the aqueous solution contains at least one of ammonia and hydrogen peroxide. A substrate processing method as claimed in claim 1 or 2, wherein the processing liquid is not heated before reaching the use point. A substrate processing method as claimed in claim 1 or 2, wherein in the step of heating the processing liquid, the processing liquid is heated to a temperature above 40°C but below the boiling point.