JP2023111564A - Substrate processing method and substrate processing apparatus - Google Patents

Abstract

To provide a substrate processing method and a substrate processing apparatus, capable of improving accuracy of an exposure performed to a front surface of a substrate for forming a pattern.SOLUTION: A semiconductor wafer W includes: a front surface Wf as a main surface, exposed for forming a pattern; and a back surface Wb as a main surface that is an opposite side of the front surface. Before the exposure for forming the pattern to the front surface of the semiconductor wafer, flatness processing for flatting the back surface is performed. The flatness processing contains: a convex part removing step of removing a convex part 91 existed in the back surface of the semiconductor wafer by chemical polishing; and a concave embedding step of embedding a flowability flexible material 96 into a concave part 92 existed on the back surface of the semiconductor wafer after the convex part removing step. After the post-processing to the front surface of the semiconductor wafer W, it is preferable to remove a sacrificial film 97 formed of the flexible material 96.SELECTED DRAWING: Figure 4

Description

The present invention relates to a substrate processing method and a substrate processing apparatus. Substrates to be processed include, for example, semiconductor wafers, FPD (Flat Panel Display) substrates such as liquid crystal display devices and organic EL (Electroluminescence) display devices, photomask substrates, ceramic substrates, solar cell substrates, and the like. .

In the manufacturing process of a semiconductor device, a substrate (specifically, a semiconductor wafer) is subjected to multiple photolithography steps. The photolithography process includes a process of forming a resist film on a substrate, a process of exposing the resist film to a predetermined pattern (pattern exposure) with an exposure device, and a process of developing the resist film after exposure. For example, in the formation of a multilayer wiring structure, alignment accuracy of exposure regions between one lithography process and the subsequent lithography process, that is, overlay accuracy, is important. A particularly high overlay accuracy is required when forming fine wiring.

The exposure apparatus includes, for example, a substrate stage that holds a substrate, a reticle stage that holds a reticle on which a circuit pattern is drawn, and projection optics that exposes the substrate on the substrate stage via the reticle (for example, shot exposure). system. The substrate stage holds the back surface of the substrate by suction. A projection type exposure apparatus holds the back surface of a substrate with a vacuum chuck. Since the EUV (Extreme Ultraviolet) exposure apparatus performs exposure in a vacuum state, the back surface of the substrate is held by an electrostatic chuck. The electrostatic chuck device includes a flat chucking stage and a large number of fine projections distributed on the chucking surface of the chucking stage, and electrostatically chucks the substrate while the numerous projections are in contact with the back surface of the substrate. It is configured to hold

In order to improve the overlay accuracy, the substrate is placed at an accurate position on the suction stage, and the exposure shot area in the previous photolithography process and the exposure shot area in the subsequent photolithography process are accurately aligned. This is very important.

In Patent Document 1, the back surface of the substrate before pattern exposure is polished to roughen the back surface, and the contact area between the back surface of the substrate and the suction stage is reduced during exposure, so that the back surface of the substrate is on the suction stage. Disclosed is a method that enables gliding. It is explained that this corrects the substrate along the surface of the suction stage to eliminate the distortion, thereby improving the overlay accuracy.

JP 2017-69271 A

However, since the flatness of the back surface of the substrate decreases due to the roughening treatment of the back surface, the front surface of the substrate may not fall within the range of the depth of focus of the exposure apparatus (focus error that does not interfere with pattern formation). Moreover, depending on the positional relationship between the unevenness formed on the back surface of the substrate by the surface roughening treatment and the protrusions provided on the suction stage, the distortion of the substrate cannot always be eliminated. It is possible that the effect may not be achieved.

Accordingly, one embodiment of the present invention provides a substrate processing method and substrate processing apparatus capable of improving the accuracy of exposure performed on the surface of a substrate to form a pattern.

One embodiment of the present invention provides a substrate processing method for processing a substrate having a front surface, which is a main surface to be exposed to form a pattern, and a back surface, which is a main surface opposite to the front surface. This substrate processing method includes a planarization process for planarizing the back surface before exposure for forming a pattern on the front surface. The planarization process includes a convex portion removing step of removing convex portions present on the back surface of the substrate by chemical polishing, and a fluid plastic material embedded in concave portions present on the back surface of the substrate after the convex portion removing step. and a recess filling step.

According to this method, the back surface of the substrate is planarized by removing the convex portions by chemical polishing and filling the concave portions with a fluid plastic material. By performing not only physical polishing but also chemical polishing using a chemical action to remove the protrusions, the protrusions can be removed while suppressing damage to the back surface of the substrate. By embedding a fluid plastic material in the recesses on the back surface of the substrate from which the protrusions have been removed, the back surface of the substrate can be planarized with high accuracy. Therefore, when the front surface of the substrate is exposed to form a pattern (pattern exposure) after flattening the back surface, the substrate can have a high degree of flatness. As a result, each part of the surface of the substrate can easily fit within the depth of focus range of the exposure apparatus. In other words, the positional accuracy of the substrate surface during exposure, particularly the positional accuracy in the focal depth direction of the exposure apparatus (specifically, the direction perpendicular to the main surface of the substrate) is increased. Thereby, the quality of pattern exposure can be improved.

In addition, when the substrate is held by suction on the suction stage during pattern exposure, problems with suction can be suppressed. In addition, the plastic material on the back surface of the substrate deforms to capture at least a portion of any foreign matter on the suction stage to which the substrate is suctioned. Thereby, adsorption failure can be further suppressed. Moreover, since the plastic material adsorbs foreign matter, the foreign matter is carried away together with the substrate when the substrate is removed from the adsorption stage. As a result, the adsorption stage can be maintained in a clean state, so that maintenance frequency of the adsorption stage can be reduced, and the operating rate of the apparatus using the adsorption stage can be increased accordingly.

In addition, the plastic material relieves the stress that the substrate receives from the suction stage, and furthermore, if there is a foreign substance on the suction stage, it relieves the stress that the foreign substance receives. This enables high-quality substrate processing while suppressing adverse effects on the characteristics of devices formed on the substrate.

In one embodiment, the convex portion removing step includes a chemical solution supply step of supplying a chemical solution to the back surface of the substrate, and a scrubbing step of scrubbing the back surface of the substrate to which the chemical solution is supplied in the chemical solution supply step with a polishing brush. ,including. By this method, the chemical action of the chemical solution and the physical action of the polishing brush are used in combination, and the protrusions on the back surface of the substrate can be removed while suppressing damage to the back surface of the substrate.

The chemical solutions include hydrofluoric acid, hydrofluoric acid/hydrogen peroxide mixture, ozone-containing hydrofluoric acid solution, ammonia/hydrogen peroxide/water mixture, ozone-containing sulfuric acid solution, hydrochloric acid/hydrogen peroxide/water mixture, ozone water, and sulfuric acid/hydrogen peroxide. It preferably contains one or more selected from the group consisting of a water mixture (SPM: Sulfuric Acid Hydrogen Peroxide Mixture) and a hydrogen peroxide solution. By selecting an appropriate chemical solution according to the material of the back surface of the substrate, the protrusion can be removed while suppressing damage to the back surface of the substrate.

The polishing brush preferably has, on its polishing surface, one or more selected from the group consisting of polyvinyl alcohol, silicon carbide, and diamond. By selecting a polishing brush made of an appropriate material according to the material of the back surface of the substrate, the protrusions on the back surface of the substrate can be removed while suppressing damage to the back surface of the substrate. More preferably, the polishing brush has a polishing surface in which abrasive grains are contained in a brush pad bonding material. In this case, the abrasive grains preferably contain one or more of cerium (Ce), silicon carbide (SiC) and diamond (C). The brush pad binding material is preferably made of PVA (polyvinyl alcohol), PP (polypropylene), PTFE (polytetrafluoroethylene, fluororesin), or the like. The polishing surface of the polishing brush can be formed according to the material of the back surface of the substrate and the chemical used.

Preferably, the plastic material includes either a resin material or a silicon-based material, or a mixture thereof. Such a plastic material can exhibit a fluid state and has moderate flexibility (elasticity) in a solidified state. As a result, it is possible to suppress the occurrence of stress concentration on the substrate when it is adsorbed by the adsorption stage. That is, it is possible to achieve high flatness of the substrate on the adsorption stage while suppressing stress concentration.

The resin material includes, for example, polyimide. The silicon-based material includes, for example, a methyl-based silicon coating material. Since these resin materials and silicon-based materials have one or more of oil repellency, water repellency, and antifouling properties, they can be expected to have the effect of protecting the back surface of the substrate.

Preferably, said plastic material comprises an organosilicon material. By using an organic silicon material (silicone) as the plastic material, when the plastic material on the back surface of the substrate comes into contact with the adsorption stage, an effect of removing foreign matter (especially particles) existing on the adsorption stage can be expected. Thereby, a special cleaning process for cleaning the adsorption stage can be eliminated or reduced in frequency. Therefore, it is possible to increase the operation rate of the apparatus using the adsorption stage.

In one embodiment, the recess filling step includes a coating step of coating the back surface of the substrate with a fluid plastic material, and after the coating step, scrubbing the back surface of the substrate with a brush to remove excess plastic material. and a surplus material removal step of removing the . By removing excess plastic material by brush scrubbing, the flatness of the back surface of the substrate with the plastic material embedded in the recesses can be improved.

In one embodiment, the step of solidifying the plastic material is further included after the applying step and before the excess material removing step. As a result, the state in which the concave portion on the back surface of the substrate is filled with the plastic material can be reliably maintained.

For example, the solidification step preferably includes at least one of a baking treatment of heating the plastic material to 100° C. to 400° C. and an ultraviolet treatment of irradiating the plastic material with ultraviolet rays. Baking is preferably performed when a heat-curable plastic material is used. When using an ultraviolet curable plastic material, it is preferable to perform an ultraviolet treatment.

In one embodiment, the substrate processing method includes, after the recess filling step, a surface treatment step of treating the surface of the substrate, and after the surface treatment step, removing the plastic material from the back surface of the substrate. and a removing step.

According to this method, since the plastic material is removed after the surface treatment process, the substrate treatment can be completed without the plastic material adhering to the back surface. Therefore, it is possible to avoid the influence of the plastic material on the substrate.

The removing step preferably includes a step of supplying an alkaline chemical solution or an oxidant-containing chemical solution to the back surface of the substrate to dissolve the plastic material.

When the plastic material is a silicon-rich organic silicon material, the plastic material can be dissolved and removed with an alkaline chemical solution. One specific example of a silicon-rich organosilicon material is UV-curable liquid silicone rubber, and more specifically PDMS (polydimethylsiloxane). Specific examples of alkaline chemicals include TMAH (tetramethylammonium hydroxide) and SC1 (ammonia-hydrogen peroxide mixture).

When the plastic material is an organic-rich organosilicon material, the plastic material can be dissolved and removed by an oxidant-containing chemical solution. One specific example of an organic-rich organosilicon material is a polyimide polymer. Specific examples of the oxidant-containing chemical solution include ozone water, ozone-containing hydrofluoric acid solution, sulfuric acid hydrogen peroxide mixture (SPM), and ozone-containing sulfuric acid solution.

In one embodiment, the surface treatment step includes a step of holding the back surface of the substrate by suction on a suction stage, and a step of pattern-exposing the front surface of the substrate held on the suction stage.

The back surface of the substrate that is sucked by the suction stage is a flat surface that has undergone a flattening process and has excellent flatness. Therefore, since the substrate sucked by the sucking stage has excellent flatness, high-quality pattern exposure is possible.

In addition, since a plastic material is applied to the back surface of the substrate (particularly inside the concave portion), the plastic material can absorb the stress when the substrate is adsorbed by the adsorption stage. In addition, foreign matter on the adsorption stage can be adsorbed by the plastic material, and the foreign matter can be taken away at the same time when the substrate is dispensed, so the adsorption stage can be kept clean.

In one embodiment, the substrate processing method further includes the step of processing the front surface of the substrate by adsorbing and holding the rear surface of the substrate on a suction stage before the planarization processing. Even if unevenness occurs on the back surface of the substrate due to the adsorption of the back surface of the substrate on the adsorption stage, the unevenness can be improved by planarization treatment, and the back surface of the substrate has excellent flatness during pattern exposure. Thereby, high-quality pattern exposure becomes possible.

In one embodiment of the present invention, a substrate having a front surface, which is a main surface on which a pattern is formed, and a back surface, which is a main surface opposite to the front surface, is subjected to exposure for forming the pattern. To provide a substrate processing apparatus for processing a substrate. This substrate processing apparatus includes a chemical polishing unit that scrubs the back surface of the substrate with a polishing brush while supplying a chemical solution to the back surface of the substrate, and a coating solution containing a fluid plastic material that is supplied to the back surface of the substrate to apply the plasticity to the back surface of the substrate. a coating unit for forming a coating film containing the material.

In one embodiment, the substrate processing apparatus further includes a transfer robot that transfers the substrate processed by the chemical polishing unit to the coating unit.

In one embodiment, the substrate processing apparatus further includes a solidification unit that processes the substrate having the coating film of the plastic material formed on the back surface thereof and solidifies the coating film.

The solidification unit preferably includes at least one of a heating unit heating the substrate and an ultraviolet processing unit irradiating the substrate with ultraviolet rays.

The chemical solutions include hydrofluoric acid, hydrofluoric acid-hydrogen peroxide solution mixture, sulfuric acid hydrogen peroxide solution mixture (SPM), ozone-containing hydrofluoric acid solution, ammonia-hydrogen peroxide solution mixture, ozone-containing sulfuric acid, It preferably contains one or more selected from the group consisting of solution, hydrochloric acid/hydrogen peroxide solution mixture, ozone water, and hydrogen peroxide solution.

The polishing brush preferably has, on its polishing surface, one or more selected from the group consisting of polyvinyl alcohol, silicon carbide, and diamond. More preferably, the polishing brush has a polishing surface in which abrasive grains are contained in a brush pad bonding material. In this case, the abrasive grains preferably contain one or more of cerium (Ce), silicon carbide (SiC) and diamond (C). The brush pad binding material is preferably made of PVA (polyvinyl alcohol), PP (polypropylene), PTFE (polytetrafluoroethylene, fluororesin), or the like.

Preferably, the plastic material includes either a resin material or a silicon-based material, or a mixture thereof.

Preferably, said plastic material comprises an organosilicon material.

FIG. 1 is a diagram for explaining problems associated with the use of an electrostatic chuck device. FIG. 2 shows a process example for improving unevenness on the back surface of the semiconductor wafer W. As shown in FIG. FIG. 3 shows another example process. FIG. 4 shows an example of a more specific process. FIG. 5 shows an example of a substrate processing system that can be used to carry out the processes described above. FIG. 6 is an illustrative plan view for explaining a configuration example of a substrate cleaning apparatus that constitutes the substrate processing system. FIG. 7 shows a configuration example of a chemical cleaning unit provided in the substrate cleaning apparatus. FIG. 8 shows a configuration example of a coating unit provided in the substrate cleaning apparatus. FIG. 9 shows a configuration example of a solidification unit provided in the substrate cleaning apparatus. FIG. 10 shows another configuration example of the solidification unit provided in the substrate cleaning apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram for explaining problems associated with the use of an electrostatic chuck device. In the manufacturing process of a semiconductor device, an electrostatic chuck device 80 is used to hold the wafer W by attracting the back surface Wb of the semiconductor wafer W, which is an example of a substrate. More specifically, the electrostatic chuck device 80 is used to hold the semiconductor wafer W to be processed in a photolithography process, an etching process, a thin film forming process, and the like.

The photolithography process includes a process of forming a resist film on the surface Wf of the semiconductor wafer W, a process of exposing the resist film, and a process of developing the resist film after exposure. For example, an exposure apparatus for exposing a resist film is provided with an electrostatic chuck device 80, and a semiconductor wafer W to be exposed is held by the electrostatic chuck device 80 with its rear surface Wb attracted.

The etching process may be, for example, a dry etching process such as reactive ion etching. The semiconductor wafer W is held with its rear surface Wb attracted by an electrostatic chuck device 80 provided in the etching apparatus, and in this state, etching is performed using a resist film or the like formed on the front surface Wf of the semiconductor wafer W as a mask. .

The thin film forming process is a process of forming a thin film by a PVD (Physical Vapor Deposition) method, a CVD (Chemical Vapor Deposition) method, or the like. A semiconductor wafer W is held by an electrostatic chuck device 80 provided in a film forming apparatus with its rear surface Wb attracted.

The electrostatic chuck device 80 includes a flat adsorption stage 81 and a large number of protrusions 83 distributed on an adsorption surface 82 of the adsorption stage 81 . The rear surface Wb of the semiconductor wafer W is attracted toward the attraction stage 81 by electrostatic force while being in contact with the convex portion 83 . Thereby, ideally, the semiconductor wafer W assumes a flat shape along the suction surface 82 of the suction stage 81 .

The rear surface Wb of the semiconductor wafer W is pressed against the convex portion 83 of the suction stage 81 when being sucked, and is released from the convex portion 83 of the suction stage 81 when the suction is released. At this time, local rubbing between the convex portion 83 and the back surface Wb of the semiconductor wafer W occurs. As a result, the material of the back surface Wb of the semiconductor wafer W falls off, and the back surface Wb of the semiconductor wafer W becomes finely uneven.

When the semiconductor wafer W having such unevenness on the back surface Wb is held by another electrostatic chuck device 80, the flatness of the semiconductor wafer W when it is attracted to the attraction stage 81 of the electrostatic chuck device 80 is It is affected by the unevenness of the back surface Wb. As a result, for example, focus shift occurs during exposure, which may cause exposure failure. Specifically, when the unevenness of the surface Wf of the semiconductor wafer W exceeds the depth of focus range of the exposure apparatus, the exposure is defective. This results in so-called depth of focus (DOF) hot spots in the resist pattern.

On the other hand, as the material of the back surface Wb of the semiconductor wafer W falls off, particles P are generated and left on the adsorption surface 82 . These particles P may cause an adsorption error when the next semiconductor wafer W is held on the adsorption stage 81 of the electrostatic chuck device 80 . Moreover, even if a suction error does not occur, the flatness of the semiconductor wafer W in the suctioned state is affected, so that, for example, defocus may occur during exposure, which may cause exposure failure. Specifically, when the unevenness of the surface Wf of the semiconductor wafer W exceeds the depth of focus range of the exposure apparatus, the exposure is defective. This causes so-called depth-of-focus hot spots in the resist pattern.

The material of the back surface Wb of the semiconductor wafer W may be the material of bare silicon (that is, silicon), or the material of the thin film (for example, a protective film such as a silicon nitride film) formed on the back surface Wb. .

FIG. 2 shows a process example for improving unevenness of the back surface Wb of the semiconductor wafer W. FIG. The semiconductor wafer W is held by the electrostatic chuck device 80 and undergoes a surface treatment process (surface process 1: photolithography, etching, film formation, etc.) in which the front surface Wf of the semiconductor wafer W is processed. As described above, unevenness occurs on the surface. The back surface Wb of the semiconductor wafer W having the irregularities on the back surface Wb is chemically polished by a polishing brush while supplying a chemical solution (back surface chemical polishing step). Thereby, the convex portion 91 on the rear surface Wb of the semiconductor wafer W is removed (convex removing step). A sacrificial film 97 is formed by embedding a fluid plastic material 96 into the recesses 92 remaining on the rear surface Wb of the semiconductor wafer W after the protrusions 91 have been removed (sacrificial film coating process, recess filling process). As a result, the back surface Wb of the semiconductor wafer W is flattened (flattening process). The semiconductor wafer W in this state exhibits excellent flatness when held by the electrostatic chuck device 80 (see FIG. 1) in the next process (eg, exposure process). Therefore, for example, the exposure process can be performed with high accuracy, so that the surface Wf of the semiconductor wafer W can be formed with a high-precision pattern.

On the other hand, when the sacrificial film 97 made of the fluid plastic material 96 is in contact with the attraction surface 82 (see FIG. 1) of the electrostatic chuck device 80, the stress from the protrusions 83 (see FIG. 1) of the attraction surface 82 is applied. absorb and relieve Furthermore, the sacrificial film 97 can at least partially take in the particles P (see FIG. 1) existing on the attraction surface 82 (especially the surface of the convex portion 83). As a result, the stress from the particles P can be absorbed, and adsorption failure can be suppressed. Moreover, since the particles P taken into the sacrificial film 97 are taken away together with the semiconductor wafer W when the semiconductor wafer W is discharged, the adsorption surface 82 can be cleaned. Therefore, the attracting surface 82 of the electrostatic chuck device 80 is kept clean without performing a special cleaning process. Thereby, the flatness of the semiconductor wafer W when it is attracted to the attraction stage 81 of the electrostatic chuck device 80 can be further improved.

FIG. 3 shows another example process. In this example, the front surface Wf of the semiconductor wafer W having the sacrificial film 97 formed on the back surface Wb through the same processes (surface process 1, back surface chemical polishing and sacrificial film coating) as in FIG. (Surface process 2: photolithography, etching, film formation, etc.) is performed. During the surface process 2, the back surface Wb of the semiconductor wafer W is held by the electrostatic chuck device 80 (see FIG. 1). As a result, unevenness caused by contact with the protrusions 83 of the attraction surface 82 of the electrostatic chuck device 80 is formed on the back surface Wb of the semiconductor wafer W on which the sacrificial film 97 is formed. Specifically, a concave portion 102 is formed in the sacrificial film 97, and a convex portion 101 is formed on the periphery thereof. A sacrificial film removing process (a sacrificial film selective removing process) for removing the sacrificial film 97 on the back surface Wb is performed on the semiconductor wafer W as described above. Thereby, the back surface Wb of the semiconductor wafer W without the sacrificial film 97 appears. Therefore, the processing of the semiconductor wafer W can be completed without leaving the influence of the sacrificial film 97 .

FIG. 4 shows an example of a more specific process. After the semiconductor wafer W to be processed is subjected to the cleaning process, the protective film 100 is formed on the back surface Wb of the semiconductor wafer W. As shown in FIG. The protective film 100 may also be formed on the front surface Wf of the semiconductor wafer W, and an example in which the protective film 100 is formed on the front surface Wf and the rear surface Wb of the semiconductor wafer W is shown in FIG. The protective film 100 is typically an insulating film, and more specifically may be a silicon nitride film.

After the protective film 100 is formed, the front surface Wf of the semiconductor wafer W is subjected to a first surface process (surface process 1; first surface treatment step). The first surface process includes, for example, one or more of a photolithography process, an etching process and a film formation process. In at least one of these processes, the back surface Wb of the semiconductor wafer W is attracted and held by the electrostatic chuck device 80 (see FIG. 1). Therefore, the rear surface Wb of the semiconductor wafer W that has undergone the first surface process is subjected to contact with a large number of protrusions 83 (see FIG. 1) provided on the attraction surface 82 of the attraction stage 81 of the electrostatic chuck device 80 . Concave and convex portions are formed. More specifically, when the protective film 100 on the back surface Wb of the semiconductor wafer W comes into contact with the projections 83 of the electrostatic chuck device 80 and is locally rubbed, the material of the protective film 100 is scraped off. A concave portion 92 is formed in the scraped portion, and a convex portion 91 is formed on the peripheral edge of the concave portion 92 . If the material separates from the protective film 100, the separated material becomes particles P (see FIG. 1).

After the first surface process, the back surface Wb of the semiconductor wafer W is subjected to chemical polishing (back surface chemical polishing step). As a result, the protrusions 91 formed on the rear surface Wb of the semiconductor wafer W are removed. By chemical polishing using both chemical action and physical action, the convex portion 91 can be removed while suppressing damage to the back surface Wb of the semiconductor wafer W (convex removing step). That is, since chemical polishing rarely damages the back surface Wb of the semiconductor wafer W (the surface of the protective film 100 in this example), the convex portions 91 are removed while suppressing the formation of new concave portions on the back surface Wb. Remove.

Chemical solutions used for chemical polishing include, for example, hydrofluoric acid (HF), hydrofluoric acid/hydrogen peroxide solution mixture (FPM), ozone-containing hydrofluoric acid solution (FOM: hydrofluoric acid/ozone solution mixture), SC1 (ammonia hydrogen peroxide water mixture), ozone-containing sulfuric acid solution (SOM. sulfuric acid ozone water mixture), SC1 (hydrochloric acid hydrogen peroxide water mixture), ozone water (O ₃ ), sulfuric acid hydrogen peroxide water mixture (SPM: Sulfuric Acid Hydrogen Peroxide Mixture), hydrogen peroxide solution (H ₂ O ₂ ), etc., or two or more.

A polishing brush used for chemical polishing may have one or more of polyvinyl alcohol (PVA), silicon carbide (SiC), diamond and the like on the polishing surface. More specifically, the polishing brush preferably has a polishing surface in which abrasive grains are contained in a brush pad bonding material. In this case, the abrasive preferably contains one or more of cerium (Ce), silicon carbide (SiC) and diamond (C). The brush pad binding material is preferably made of PVA (polyvinyl alcohol), PP (polypropylene), PTFE (polytetrafluoroethylene, fluororesin), or the like.

After the chemical polishing, the semiconductor wafer W is washed to wash away substances dropped from the semiconductor wafer W due to dissolution by the chemical solution and shear force due to polishing.

After chemical polishing of the back surface Wb of the semiconductor wafer W and subsequent necessary cleaning are completed, the back surface Wb of the semiconductor wafer W is coated with a sacrificial film. Specifically, a fluid plastic material 96 is embedded in the concave portion 92 formed in the back surface Wb of the semiconductor wafer W (more specifically, the exposed portion of the protective film 100) (concave portion filling step).

The sacrificial film coating includes, for example, a coating step of coating the back surface Wb of the semiconductor wafer W with the fluid plastic material 96 (material of the sacrificial film 97) and a surplus plastic material 96 of removing the surplus plastic material 96 from the back surface Wb of the semiconductor wafer W. and a material removal step. Through the coating process, the plastic material 96 is embedded in the concave portion 92 of the back surface Wb of the semiconductor wafer W, and the plastic material 96 is also deposited on the flat portion 93 outside the concave portion 92 to form a coating film. After the coating process, it is preferable to perform a solidification process for solidifying the coating film formed on the back surface Wb of the semiconductor wafer W, and it is preferable to perform a surplus material removal process after the solidification process.

The excess material removal step removes the plastic material 96 deposited on the flat portion 93 outside the recess 92 . However, it is not necessary to remove all the plastic material 96 deposited on the flat portion 93, and the plastic material 96 may be left on the flat portion 93 as long as the back surface Wb of the semiconductor wafer W becomes flat as a whole. The excess material removal step may be performed by chemical polishing. The chemical polishing is preferably performed under conditions with a high removal selectivity ratio of the plastic material 96 to the material of the protective film 100, thereby selectively removing the plastic material 96 while suppressing damage to the protective film 100. , the back surface Wb of the semiconductor wafer W can be planarized.

After the coating process, it is preferable to perform an edge rinse process for cleaning the plastic material 96 adhering to the edge portion (particularly the peripheral end face) of the semiconductor wafer W prior to the excess material removing process.

The solidification step may be a step of cooling and solidifying the coating film, or a step of heating and solidifying (baking step). The solidification step is preferably performed after the edge rinse step described above. For example, the baking step may be heating the plastic material 96 to between 100.degree. C. and 400.degree. A cooling step for cooling the semiconductor wafer W, for example, to room temperature is preferably performed after the baking step. The room temperature is the environmental temperature of the space in which the processing equipment for processing the semiconductor wafer W is arranged, and more specifically, the temperature in the clean room of the semiconductor device manufacturing factory. Typical room temperature ranges are generally from 0°C to 30°C, more specifically for example from 20°C to 30°C. for example, 23°C).

Further, the solidification step may be an ultraviolet irradiation step of irradiating the coating film with ultraviolet rays. UV treatment may be performed instead of or in addition to the baking process. When using the plastic material 96 having a composition that is cured by ultraviolet rays, it is preferable to perform an ultraviolet irradiation step.

The fluid plastic material 96 used in the coating process includes either or a mixed material of a resin material and a silicon-based material. The resin material includes polyimide, for example. Silicon-based materials include, for example, methyl-based silicon coating materials. The plastic material 96 preferably has one or more of oleophobic, water repellent and stain resistant properties. Polyimide and methyl-based silicone coating materials are both oleophobic, water repellent and antifouling materials. More specifically, the plastic material 96 may be a cleaning material used for the cleaning surface of a chuck cleaning wafer that cleans the chuck surface of the electrostatic chuck device 80 . Typical cleaning materials include at least one of polyimide and methyl-based silicone coating materials. Also, typical cleaning materials are organosilicon materials. By using these materials as the plastic material 96 , when the sacrificial film 97 comes into contact with the attraction surface 82 of the electrostatic chuck device 80 , it attracts foreign matter (mainly particles P) on the attraction surface 82 .

In the chemical polishing in the excess material removing step, when the plastic material 96 is an organic-rich organic silicon material, it is preferable to use a chemical solution containing an oxidant such as ozone (oxidant-containing chemical solution). Further, when the plastic material 96 is a silicon-rich organic silicon material, it is preferable to use an alkaline chemical such as TMAH (tetramethylammonium hydroxide) or SC1 (ammonia-hydrogen peroxide mixture). In either case, in chemical polishing, the organic silicon material, which is the plastic material 96, can be dissolved with a chemical solution. In parallel with such a dissolving action, the back surface Wb of the semiconductor wafer W is physically polished by the polishing brush 43 . The polishing brush 43 preferably has a polishing surface made of polyvinyl alcohol, silicon carbide, or diamond. More specifically, the polishing brush 43 preferably has a polishing surface made of a brush pad binding material containing abrasive grains. In this case, the abrasive preferably contains one or more of cerium (Ce), silicon carbide (SiC) and diamond (C). The brush pad binding material is preferably made of PVA (polyvinyl alcohol), PP (polypropylene), PTFE (polytetrafluoroethylene, fluororesin), or the like.

After the sacrificial film coating, the surface Wf of the semiconductor wafer W is subjected to a second surface process (surface process 2; second surface treatment step). The second surface process includes, for example, one or more of a photolithography process, an etching process and a film formation process. In at least one of these processes, the back surface Wb of the semiconductor wafer W is attracted and held by the electrostatic chuck device 80 (see FIG. 1). Therefore, the rear surface Wb of the semiconductor wafer W that has undergone the second surface process is affected by contact with a large number of protrusions 83 (see FIG. 1) provided on the attraction surface 82 of the attraction stage 81 of the electrostatic chuck device 80 . Concave and convex portions are formed. More specifically, when the sacrificial film 97 or the protective film 100 on the back surface Wb of the semiconductor wafer W comes into contact with the projections 83 of the electrostatic chuck device 80 and is locally rubbed, these film materials are scraped off. . Concave portions 92 and 102 are formed in the film portions that have been scraped off, and convex portions 91 and 101 are formed on the peripheral edges of the concave portions 92 and 102 . When the film material separates, the separated material becomes particles P (see FIG. 1).

After the second surface process, a step of selectively removing the sacrificial film 97 on the back surface Wb of the semiconductor wafer W (sacrificial film selective removal) is performed. As a result, the back surface Wb of the semiconductor wafer W becomes a surface on which the sacrificial film 97 does not exist. Specifically, in this example, the back surface Wb of the semiconductor wafer W is the surface covered with the protective film 100 .

The selective removal of the sacrificial film 97 is preferably chemical solution processing using a chemical solution selected according to the film material of the sacrificial film 97 . Specifically, when the sacrificial film 97 is made of an organic-rich organic silicon material, it is preferable to use a chemical solution containing an oxidant such as ozone (an oxidant-containing chemical solution). Further, when the sacrificial film 97 is made of a silicon-rich organic silicon material, it is preferable to use an alkaline chemical such as TMAH (tetramethylammonium hydroxide) or SC1 (ammonia-hydrogen peroxide mixture). In either case, the organic silicon material, which is the plastic material 96, can be dissolved and removed with a chemical solution.

One specific example of an organic-rich organosilicon material is a polyimide polymer. One specific example of the silicon-rich organosilicon material is UV curable liquid silicone rubber, more specifically PDMS (polydimethylsiloxane).

According to the process of this specific example, the semiconductor wafer W has a front surface Wf, which is the main surface to be exposed to form a pattern, and a back surface Wb, which is the main surface opposite to the front surface Wf. Before exposure for forming a pattern for the second surface process (surface process 2) on the surface Wf, a planarization process for planarizing the back surface Wb is performed. The planarization process includes a convex portion removing step (back surface chemical polishing) for removing the convex portions 91 existing on the back surface Wb of the semiconductor wafer W by chemical polishing, and the convex portion removing step on the back surface Wb of the semiconductor wafer W after this convex portion removing step. and a recess filling step (sacrificial film coating) of filling the recess 92 with a fluid plastic material 96 .

Therefore, the back surface Wb of the semiconductor wafer W is flattened by not only polishing the convex portions 91 but also filling the concave portions 92 with a fluid plastic material 96, so that the semiconductor wafer W can be subjected to pattern forming exposure (pattern During exposure), a high degree of flatness can be achieved on the adsorption stage 81 of the electrostatic chuck device 80 provided in the exposure apparatus. Moreover, the convex portion 91 can be removed while suppressing damage to the rear surface Wb of the semiconductor wafer W by performing not only physical polishing but also chemical polishing that uses a chemical action to remove the convex portion 91 . By embedding a fluid plastic material 96 in the concave portions 92 of the back surface Wb of the semiconductor wafer W from which the convex portions have been removed, the back surface Wb of the semiconductor wafer W can be flattened with high accuracy. This makes it easier for the surface Wf of the semiconductor wafer W to fit within the depth of focus range of the exposure apparatus. In other words, the positional accuracy of the surface of the semiconductor wafer W is improved. As a result, the quality of pattern exposure by the exposure apparatus can be improved, and the frequency of occurrence of depth-of-focus hot spots in the resist pattern can be reduced. As a result, the frequency of maintenance based on, for example, Statistical Process Control (SPC) can be reduced, thereby reducing the effort for maintenance, and the utility (plant utility equipment) used for maintenance. ) can be reduced.

In addition, since the back surface Wb of the semiconductor wafer W is flattened with high accuracy, it is possible to suppress the adsorption failure in the electrostatic chuck device 80 . In addition, the sacrificial film 97 made of the plastic material 96 can take in at least part of foreign matter if it exists on the attraction surface 82 of the electrostatic chuck device 80 and attract it. Since the foreign matter is carried away together with the semiconductor wafer W when it is dispensed, the attraction surface 82 can be kept clean. As a result, adsorption defects can be further suppressed, and the operation rate of the device using the electrostatic chuck device 80 can be improved. That is, since the frequency of maintenance such as parts replacement and cleaning can be reduced, the labor for maintenance can be reduced, and the utility used for maintenance can be reduced.

Furthermore, the sacrificial film 97 made of the plastic material 96 can relieve the stress received from the projections 83 distributed on the chucking surface 82 of the electrostatic chuck device 80. Stress received from foreign matter can be relaxed. Thereby, the back surface Wb of the semiconductor wafer W can be more favorably attracted to the attraction surface 82 . Moreover, high-quality processing can be achieved while suppressing adverse effects of stress on the characteristics of devices manufactured on the semiconductor wafer W.

The material of the polishing surface of the polishing brush 43 used to remove the protrusions 91 on the back surface Wb of the semiconductor wafer W is appropriately selected according to the material of the back surface Wb of the semiconductor wafer W (bare silicon, protective film 100, etc.). preferably. Specifically, the polishing brush 43 may have polyvinyl alcohol, silicon carbide, or diamond on the polishing surface. More preferably, the polishing brush 43 has a polishing surface in which abrasive grains are contained in a brush pad bonding material. In this case, the abrasive grains preferably contain one or more of cerium (Ce), silicon carbide (SiC) and diamond (C). The brush pad binding material is preferably made of PVA (polyvinyl alcohol), PP (polypropylene), PTFE (polytetrafluoroethylene, fluororesin), or the like.

Specific examples of the plastic material 96 are as described above. In particular, by using an organic silicon material, when the sacrificial film 97 on the back surface Wb of the semiconductor wafer W contacts the adsorption stage 81 of the electrostatic chuck device 80, This is preferable because it has the effect of removing foreign matter (especially particles P) existing on the adsorption stage 81 . Thereby, a special cleaning process for cleaning the adsorption stage 81 can be eliminated or reduced in frequency. As a result, it is possible to increase the operation rate of the processing equipment (etching equipment, film forming equipment, exposure equipment, etc.) using the electrostatic chuck device 80, thereby contributing to the improvement of productivity.

The substrate processing as described above is achieved, for example, by transferring the semiconductor wafers W to be processed between a plurality of substrate processing apparatuses. Here, as an example, a case where a substrate cleaning device 1, a film forming device 2, a resist coating and developing device 3, an exposure device 4, and a dry etching device 5 are used will be described with reference to FIG.

A semiconductor wafer W to be processed is transported (for example, automatically transported) between the above devices by a carrier transport device 6, which is a substrate transport device. The carrier transfer device 6 is configured to transfer a carrier C (see FIG. 6) capable of accommodating a plurality of semiconductor wafers W. As shown in FIG. However, the semiconductor wafer W may be directly transferred between the resist coating/developing device 3 and the exposure device 4 without using the carrier transfer device 6 .

The substrate cleaning apparatus 1, for example, cleans a semiconductor wafer W before processing, chemically polishes the back surface Wb of the semiconductor wafer W (back surface chemical polishing), and coats the back surface Wb of the semiconductor wafer W with a sacrificial film 97 (sacrificial film coating). , for removing the sacrificial film 97 on the rear surface Wb of the semiconductor wafer W (selective sacrificial film removal). A specific configuration example of the substrate cleaning apparatus 1 will be described later.

The film forming apparatus 2 forms various films on the front surface Wf of the semiconductor wafer W (formation in the front surface processes 1 and 2), such as the formation of the protective film 100 on the rear surface Wb of the semiconductor wafer W (back surface protective film formation). membrane process). Specifically, the film forming apparatus 2 may be an apparatus for forming various films such as an insulating film on the surface Wf of the semiconductor wafer W by CVD, PVD, or the like.

The resist coating and developing device 3 has a function of coating a front surface Wf of the semiconductor wafer W with a resist, baking the coated resist to form a hardened resist film, and dispensing the resist to the exposure device 4 . Further, the resist coating and developing device 3 has a function of developing the resist film after being exposed by the exposure device 4 to form a patterned resist film (resist pattern). That is, the resist coating/developing device 3 and the exposure device 4 are responsible for photolithography steps in the surface processes 1 and 2 .

The exposure device 4 is a device that selectively exposes a resist film formed on the surface Wf of the semiconductor wafer W according to an electronic circuit pattern. The exposure device 4 may be a scanner device such as an EUV (Extreme Ultraviolet) scanner that performs exposure while scanning a long and narrow slit-shaped region in the horizontal direction, or a device that repeats exposure for each unit region called an exposure shot (a so-called stepper). ).

The dry etching apparatus 5 performs an etching process (etching steps of surface processes 1 and 2) on the semiconductor wafer W having the resist pattern formed on the front surface Wf, using the resist pattern as a mask. The dry etching device 5 may be, for example, a reactive ion etching device.

FIG. 6 is a schematic plan view for explaining a configuration example of a substrate cleaning apparatus 1, which is a substrate processing apparatus according to an embodiment of the present invention. An arrangement example is shown. The substrate cleaning apparatus 1 has an indexer section 10 and a process section 25 . The substrate cleaning apparatus 1 further includes a control device 15 that controls each part of the apparatus. The control device 15 typically has a configuration as a computer and includes a processor (CPU) 16 and memory 17 . Various operations of the substrate cleaning apparatus 1 are realized by the processor 16 executing the programs stored in the memory 17 .

The indexer section 10 comprises a carrier holder 11 and an indexer robot 12 . In this embodiment, a plurality of carrier holding portions 11 are provided. Each carrier holding portion 11 is configured to hold one carrier C. As shown in FIG. The carrier C is typically configured to hold a plurality of horizontally positioned semiconductor wafers W stacked vertically. Examples of the carrier C include a FOUP (Front Opening Unified Pod), a SMIF (Standard Mechanical Interface) pod, and an OC (Open Cassette). The indexer robot 12 can put the semiconductor wafer W in and out of the carrier C held by the carrier holding part 11 and put the semiconductor wafer W in and out of the process section 25 . The indexer robot 12 thereby transfers the semiconductor wafer W between the carrier C and the process section 25 . Specifically, the indexer robot 12 takes out the unprocessed semiconductor wafer W from the carrier C and loads it into the process section 25 . The indexer robot 12 also unloads the processed semiconductor wafer W from the process section 25 and loads the semiconductor wafer W into the carrier C. As shown in FIG.

The process section 25 includes a substrate waiting and reversing unit 26 , a plurality of processing units 20 and a main transfer robot 27 . The main transfer robot 27 accesses the substrate waiting and reversing unit 26 and the plurality of processing units 20 to transfer the semiconductor wafer W therebetween. More specifically, the main transfer robot 27 includes a hand 28 that holds the semiconductor wafer W, and a hand drive mechanism 29 that moves the hand 28 horizontally and vertically and rotates it about the vertical axis. The hand drive mechanism 29 typically includes actuators such as cylinders and electric motors. The main transfer robot 27 causes the hand 28 to access the substrate waiting and reversing unit 26 and the plurality of processing units 20, and transfers the semiconductor wafer W therebetween. More specifically, the main transfer robot 27 receives an unprocessed semiconductor wafer W from the substrate standby and reversing unit 26 and loads the semiconductor wafer W into one of the processing units 20 . When the processing by the processing unit 20 is completed, the main transfer robot 27 unloads the processed semiconductor wafer W and either carries it into another processing unit 20 for another processing, or transfers it to the substrate standby reversing unit 26. bring in.

The substrate standby and reversing unit 26 is a substrate standby unit that provides a standby place for the semiconductor wafers W transferred between the indexer section 10 and the process section 25 . Further, the substrate standby reversing unit 26 is also a substrate reversing unit having a function of reversing the upper and lower surfaces of the semiconductor wafer W. FIG. Specifically, the substrate standby and reversing unit 26 includes a substrate holder 26a that horizontally holds one or more semiconductor wafers W, and the substrate holder 26a that is held by the substrate holder 26a by rotating the substrate holder 26a around a horizontal rotation axis. and a rotation mechanism (not shown) for exchanging the upper and lower surfaces of the semiconductor wafer W. The rotating mechanism typically includes an actuator such as an electric motor.

When a semiconductor wafer W with its front surface facing upward is accommodated in the carrier C and the back surface of the semiconductor wafer W is to be processed, the substrate standby reversing unit 26 reverses the upper and lower surfaces of the semiconductor wafer W. be. That is, upon receiving an unprocessed semiconductor wafer W from the indexer robot 12, the substrate standby reversing unit 26 turns over the semiconductor wafer W so that the back surface Wb of the semiconductor wafer W becomes the top surface. The semiconductor wafer W is unloaded from the substrate standby and reversing unit 26 by the main transport robot 27 and loaded into the processing unit 20 . Further, upon receiving the processed semiconductor wafer W from the main transfer robot 27, the substrate standby reversing unit 26 reverses the semiconductor wafer W upside down so that the front surface Wf of the semiconductor wafer W becomes the upper surface. The semiconductor wafer W is accommodated in the carrier C by the indexer robot 12 . Accordingly, the carrier C accommodates the processed semiconductor wafer W with its surface facing upward.

In this embodiment, the processing unit 20 is a single-wafer type processing unit that processes the semiconductor wafers W one by one. The multiple processing units 20 include, for example, a chemical cleaning unit 21, a coating unit 22, and a solidification unit 23. A plurality of processing units 20 of the same type may be provided. Also, a unit capable of chemical cleaning and coating may be provided. FIG. 6 shows one chemical cleaning unit 21, one coating unit 22, and two solidification units 23 in plan view. However, the plurality of processing units 20 may be stacked in the vertical direction and arranged three-dimensionally, and the number and arrangement thereof are not limited to the example in FIG.

The chemical cleaning unit 21 performs, for example, a cleaning process of the semiconductor wafer W before the front surface process 1, a back surface chemical polishing process, a surplus material removal process at the time of sacrificial film coating, and a sacrificial film selective removal process (removal) after the surface process 2. process). A chemical cleaning unit is an example of a chemical polishing unit. The coating unit 22 performs, for example, a coating process and an edge rinse process for sacrificial film coating. The solidification unit 23 performs a solidification process for solidifying the coating film of the plastic material during the sacrificial film coating. The solidification unit 23 may be, for example, a heat treatment unit that performs baking and cooling after baking. Further, the solidification unit 23 may be an ultraviolet irradiation unit (ultraviolet treatment unit) that irradiates ultraviolet rays to solidify the plastic material.

FIG. 7 shows a configuration example of the chemical cleaning unit 21. As shown in FIG. The chemical cleaning unit 21 includes a spin chuck 31 as a substrate holder that horizontally holds a semiconductor wafer W, a rotation drive mechanism 32 that rotates the spin chuck 31 around a vertical rotation axis, and a semiconductor wafer held by the spin chuck 31. It includes a processing liquid supply unit 33 that supplies processing liquid to W, and a scrubbing unit 42 that scrubs (polishes) the upper surface of the semiconductor wafer W held by the spin chuck 31 .

The spin chuck 31 is arranged inside the processing cup 30 . The rotary drive mechanism 32 typically includes an electric motor.

The processing liquid supply unit 33 includes a chemical liquid supply unit 34 and a rinse liquid supply unit 38 . The chemical liquid supply unit 34 is interposed in the chemical liquid nozzle 35 for discharging the chemical liquid toward the upper surface of the semiconductor wafer W held by the spin chuck 31, the chemical liquid pipe 36 for supplying the chemical liquid to the chemical liquid nozzle 35, and the chemical liquid pipe 36. and a chemical liquid valve 37 for opening and closing the flow path. The rinse liquid supply unit 38 includes a rinse liquid nozzle 39 that discharges a rinse liquid (deionized water, carbonated water, etc.) toward the upper surface of the semiconductor wafer W held by the spin chuck 31 and a rinse liquid to the rinse liquid nozzle 39 . It includes a rinsing liquid pipe 40 to be supplied and a rinsing liquid valve 41 interposed in the rinsing liquid pipe 40 to open and close the flow path. The chemical liquid nozzle 35 and/or the rinse liquid nozzle 39 may be a fixed nozzle that ejects the processing liquid (chemical liquid or rinse liquid) toward a certain position on the upper surface of the semiconductor wafer W. It may be a movable nozzle (so-called scan nozzle) whose liquid landing position is variable.

By supplying the chemical liquid to the semiconductor wafer W from the chemical liquid supply unit 34 while holding and rotating the semiconductor wafer W by the spin chuck 31 , the semiconductor wafer W can be processed with the chemical liquid. Further, the supply of the chemical solution is stopped, and while the semiconductor wafer W is held and rotated by the spin chuck 31, the rinse solution supply unit 38 supplies the semiconductor wafer W with the rinse solution, thereby rinsing the chemical solution on the semiconductor wafer W. A rinsing treatment for replacing with a liquid can be performed. Then, the supply of the rinsing liquid is stopped and the rotation of the spin chuck 31 (that is, the rotation of the semiconductor wafer W) is accelerated to perform a drying process (spin drying) to shake off the rinsing liquid adhering to the semiconductor wafer W. can be done.

The chemical liquid supply unit 34 may be configured to supply a plurality of types of chemical liquids, and may be provided with a plurality of chemical liquid nozzles 35 and chemical liquid supply systems corresponding to the number of types of chemical liquids. The chemical solution supply unit 34 performs, for example, a cleaning process of the semiconductor wafer W before the front surface process 1, a back surface chemical polishing process, a surplus material removal process at the time of sacrificial film coating, and a sacrificial film selective removal process (removal) after the surface process 2. process) can be supplied with the necessary chemicals.

The scrubbing unit 42 includes a polishing brush 43 (scrubbing brush), a swing arm 44 that holds the polishing brush 43 , and an arm drive mechanism 45 that drives the swing arm 44 . The arm drive mechanism 45 vertically moves the swing arm 44 and swings it about a vertical axis. For such operations, the arm drive mechanism 45 has actuators such as cylinders and electric motors. By driving the swing arm 44 by the arm driving mechanism 45, the polishing brush 43 can contact the upper surface of the semiconductor wafer W held by the spin chuck 31 and move in the radial direction of the semiconductor wafer W. can do. Such an operation is performed while rotating the semiconductor wafer W by the spin chuck 31, so that the polishing brush 43 can scrub the upper surface of the semiconductor wafer W while scanning it.

The polishing brush 43 can be used for scrubbing the back surface Wb of the semiconductor wafer W in the back surface chemical polishing step and the excess material removing step. That is, while performing the chemical solution supply step by supplying an appropriate chemical solution from the chemical solution supply unit 34 to the upper surface of the semiconductor wafer W, the scrubbing step of scrubbing the upper surface of the semiconductor wafer W with the polishing brush 43 is performed to perform the back surface chemical polishing step. Alternatively, an excess material removal step can be performed.

FIG. 8 shows a configuration example of the coating unit 22 . The coating unit 22 includes a spin chuck 51 as a substrate holder that horizontally holds the semiconductor wafer W, a rotation drive mechanism 52 that rotates the spin chuck 51 around a vertical axis, and a coating liquid that is supplied to the upper surface of the semiconductor wafer W. A coating liquid supply unit 53 and an edge rinse unit 57 for cleaning the peripheral edge of the semiconductor wafer W are included.

The spin chuck 51 is preferably configured to hold the semiconductor wafer W with the peripheral edge of the semiconductor wafer W exposed over the entire circumference. Preferably, the semiconductor wafer W is held by a mechanism for holding portions other than the device surface on the wafer W, for example, a chuck pin holding mechanism as illustrated in FIG. The chuck pin gripping mechanism preferably includes a chuck pin opening/closing mechanism for switching between a state in which the chuck pin is in contact with the wafer W for rinsing the end face of the semiconductor wafer W and a state in which the chuck pin is not in contact. If the device surface is protected by a protective film such as a sacrificial film and can withstand mechanical damage, the device surface may be sucked and held by a vacuum chuck. For example, it may be a vacuum chuck that holds the central portion of the lower surface of the semiconductor wafer W by suction. A spin chuck 51 is arranged in the processing cup 50 . Rotation drive mechanism 52 typically includes an electric motor.

The coating liquid supply unit 53 includes a coating liquid nozzle 54 for discharging the coating liquid, a coating liquid pipe 55 for supplying the coating liquid to the coating liquid nozzle 54, and a coating liquid interposed in the coating liquid pipe 55 for opening and closing the flow path. valve 56; The coating liquid nozzle 54 may be a fixed nozzle that discharges the coating liquid toward the center of rotation of the semiconductor wafer W, or may be a fixed nozzle that dispenses the coating liquid toward the center of rotation of the semiconductor wafer W. It may be a moving nozzle (so-called scan nozzle) that ejects liquid. A coating liquid is a fluid plastic material.

As the spin chuck 51 rotates the semiconductor wafer W and the coating liquid is discharged toward the upper surface thereof, the coating liquid that has landed on the upper surface of the semiconductor wafer W receives centrifugal force and spreads over the entire upper surface. Thereby, the upper surface of the semiconductor wafer W can be coated with the coating liquid. By holding the semiconductor wafer W on the spin chuck 51 with the back surface of the semiconductor wafer W facing upward, the coating liquid can be applied to the back surface Wb of the semiconductor wafer W to form a coating film. This coating film forms a sacrificial film that is embedded in the concave portion of the back surface of the semiconductor wafer W. As shown in FIG.

The edge rinse unit 57 selectively removes the coating liquid adhering to the peripheral edge portion (especially peripheral end face) of the semiconductor wafer W. As shown in FIG. The edge rinse unit 57 may include a cleaning brush that contacts the periphery of the semiconductor wafer W. FIG. Further, the edge rinse unit 57 may include a cleaning liquid nozzle for discharging the cleaning liquid toward the peripheral edge of the semiconductor wafer W. FIG. For example, by operating the edge rinse unit 57 while rotating the semiconductor wafer W by the spin chuck 51 , the edge rinse process can be performed over the entire periphery of the semiconductor wafer W. FIG.

FIG. 9 shows a configuration example of the solidification unit 23. As shown in FIG. The solidification unit 23 is a heat treatment unit including a heating unit 23H (baking unit) and a cooling unit 23C in this example. In this example, the solidification unit 23 further includes a local transfer device 23R that transfers the semiconductor wafer W within the unit.

The heating unit 23H includes a hot plate 60 on which a semiconductor wafer W is placed and which heats the semiconductor wafer W. As shown in FIG. The hot plate 60 typically includes a plate body 61 with high thermal conductivity and a heater 62 in contact with the plate body 61 . As the heating unit, a light source arranged above the semiconductor wafer W, for example, a lamp light source such as an LED light source or a halogen lamp may be used to heat the semiconductor wafer W. FIG. In this case, the surface coated with the coating liquid faces the light source.

A transfer unit 63 for transferring the semiconductor wafer W between the local transfer device 23R and the hot plate 60 may be provided. The transfer unit 63 includes support pins 64 that move up and down while supporting the semiconductor wafer W from below by moving up and down through the heating surface of the hot plate 60, and a pin elevating mechanism 65 that moves the support pins 64 up and down. and may be provided. The pin lifting mechanism 65 has an actuator such as a cylinder or an electric motor as a drive source.

The cooling unit 23C is a unit that cools the semiconductor wafer W heat-treated by the heating unit 23H to, for example, room temperature. The cooling unit 23C includes a cool plate 70 on which the semiconductor wafer W is mounted and which cools the semiconductor wafer W. As shown in FIG. The cool plate 70 typically includes a plate body 71 with high thermal conductivity and a cooling element 72 in contact with the plate body 71 . The cooling element 72 may be an electric cooling element such as a Peltier element, or may be a non-electric cooling element such as a cooling water flow path. A transfer unit 73 for transferring the semiconductor wafer W between the main transfer robot 27 and the local transfer device 23R and the cool plate 70 may be provided. The transfer unit 73 includes support pins 74 that move up and down while supporting the semiconductor wafer W from the bottom surface by penetrating the heating surface of the cool plate 70 and moving up and down, and a pin elevating mechanism 75 that moves the support pins 74 up and down. and may be provided. The pin lifting mechanism 75 has an actuator such as a cylinder or an electric motor as a drive source.

The local transport device 23R includes, for example, a local transport hand 77 that holds the semiconductor wafer W and a hand driving mechanism 78 that drives the local transport hand 77. As shown in FIG. Hand drive mechanism 78 typically includes an actuator such as a cylinder or an electric motor.

For example, the main transfer robot 27 delivers the semiconductor wafer W to the support pins 74 of the cooling unit 23C. At this time, the support pin 74 is in the upper position, and its tip is positioned above the cool plate 70 . The local transfer device 23R receives the semiconductor wafer W from the support pins 74 and transfers it to the support pins 64 of the heating unit 23H. At this time, the support pin 64 is in the upper position, and its tip is positioned above the hot plate 60 . The semiconductor wafer W is baked by lowering the support pins 64 and placing the semiconductor wafer W on the heating surface (upper surface) of the hot plate 60 . After the baking process, when the support pins 64 rise and push up the semiconductor wafer W, the local transfer device 23R receives the semiconductor wafer W, transfers it to the cooling unit 23C, and passes it to the support pins 74. FIG. The semiconductor wafer W is cooled by lowering the support pins 74 and placing the semiconductor wafer W on the cooling surface (upper surface) of the cool plate 70 . After the semiconductor wafer W is cooled, the support pins 74 are lifted to push up the semiconductor wafer W, and the main transfer robot 27 receives the semiconductor wafer W from the support pins 74 and carries it out of the solidification unit 23 .

In this example, the transfer of the semiconductor wafer W between the cooling unit 23C and the heating unit 23H is performed by the local transfer device 23R, but this transfer may be performed by the main transfer robot 27.

FIG. 10 shows another configuration example of the solidification unit 23 . The solidification unit 23 is an ultraviolet irradiation unit (an example of an ultraviolet processing unit) that irradiates the semiconductor wafer W with ultraviolet rays in this example. The solidification unit 23 in this example includes a flat support plate 111 that supports the semiconductor wafer W, and an ultraviolet lamp 112 arranged above the support plate 111 . By irradiating the semiconductor wafer W with ultraviolet rays from the ultraviolet lamps 112 while the semiconductor wafer W is supported by the support plate 111, the ultraviolet irradiation treatment can be performed. If the back surface Wb (upper surface) of the semiconductor wafer W is formed with a coating film of an ultraviolet curable plastic material, the coating film can be cured by irradiating ultraviolet rays.

A transfer unit 113 for transferring the semiconductor wafer W between the main transfer robot 27 and the support plate 111 may be provided. The transfer unit 113 vertically moves through the support surface (upper surface) of the support plate 111 to support the semiconductor wafer W from the bottom surface and vertically move the support pins 114 and pins for vertically moving the support pins 114 . A lifting mechanism 115 may be provided. The pin lifting mechanism 115 has an actuator such as a cylinder or an electric motor as a drive source.

Next, an operation example of the substrate cleaning apparatus 1 will be described. These operation examples are realized by control operations by the control device 15 . That is, the controller 15 is programmed to control each part of the substrate cleaning apparatus 1 so as to implement these operation examples.

An operation example of the substrate cleaning apparatus 1 in the cleaning process for cleaning the semiconductor wafer W before the back surface protective film forming process is as follows. That is, when the carrier C housing the semiconductor wafer W before the back surface protective film forming process is loaded into the carrier holding unit 11 , the indexer robot 12 unloads it and passes it to the substrate standby reversing unit 26 . The main transfer robot 27 unloads the semiconductor wafer W and carries it into the chemical cleaning unit 21 . The chemical solution cleaning unit 21 performs a process of cleaning the semiconductor wafer W. FIG. This process includes a chemical solution process of supplying a chemical solution to the semiconductor wafer W while rotating the semiconductor wafer W, a rinsing process of replacing the chemical solution adhering to the semiconductor wafer W with a rinsing solution while rotating the semiconductor wafer W, and a rotation of the semiconductor wafer W. is accelerated to shake off the rinse liquid adhering to the semiconductor wafer W (spin dry). After such processing is completed, the main transfer robot 27 unloads the semiconductor wafer W from the chemical cleaning unit 21 and carries it into the substrate standby reversing unit 26 . The semiconductor wafer W is taken out by the indexer robot 12 and carried into the carrier C. As shown in FIG. The substrate standby reversing unit 26 only needs to provide a temporary standby place for the semiconductor wafers W transferred between the indexer robot 12 and the main transfer robot 27, and the semiconductor wafers W do not need to be reversed upside down.

An operation example of the substrate cleaning apparatus 1 during the back surface chemical polishing process and the sacrificial film coating process is as follows. When the carrier C housing the semiconductor wafer W that has undergone the surface process 1 is carried into the carrier holding section 11 , the indexer robot 12 carries it out and passes it to the substrate waiting and reversing unit 26 . The substrate standby reversing unit 26 performs a reversing operation of reversing the upper and lower surfaces of the semiconductor wafer W so that the back surface Wb of the semiconductor wafer W becomes the upper surface. After that, the main transfer robot 27 unloads the semiconductor wafer W and carries it into the chemical cleaning unit 21 . The chemical solution cleaning unit 21 performs a back surface chemical polishing process on the semiconductor wafer W, and removes the protrusions present on the back surface Wb of the semiconductor wafer W by using both chemical action and physical action (convex removal process ). After that, the chemical cleaning unit 21 supplies a processing liquid (chemical and/or rinsing liquid) to the semiconductor wafer W while rotating the semiconductor wafer W to wash away the residue on the semiconductor wafer W. is accelerated to dry the rinse solution, and the treatment is completed. Then, the main transfer robot 27 unloads the semiconductor wafer W from the chemical cleaning unit 21 and carries it into the coating unit 22 . The coating unit 22 rotates the semiconductor wafer W and discharges a coating liquid (a fluid plastic material) onto the upper surface thereof. Thereby, a coating film covering the back surface of the semiconductor wafer W is formed. After that, an edge rinse process for cleaning the coating film adhering to the peripheral portion of the semiconductor wafer W is performed. After the rotation of the semiconductor wafer W has stopped, the main transfer robot 27 takes out the semiconductor wafer W from the coating unit 22 and carries it into the solidification unit 23 . The solidification unit 23 performs a solidification step of solidifying the coating film formed on the back surface of the semiconductor wafer W. As shown in FIG. After that, the main transfer robot 27 transfers the semiconductor wafer W from the solidification unit 23 to the chemical cleaning unit 21 . The chemical cleaning unit 21 performs a surplus material removing step of removing surplus plastic material from the back surface Wb of the semiconductor wafer W. FIG. Specifically, while rotating the semiconductor wafer W, a chemical solution is supplied to the back surface Wb of the semiconductor wafer W, and the back surface Wb of the semiconductor wafer W is polished by the polishing brush 43 . As a result, excess plastic material is removed from the rear surface Wb of the semiconductor wafer W. As shown in FIG. After that, while rotating the semiconductor wafer W, a processing liquid (chemical and/or liquid) is supplied to the semiconductor wafer W to wash off the residue from the semiconductor wafer W. is accelerated to shake off the liquid component from the semiconductor wafer W, and a drying process is performed. When the rotation of the semiconductor wafer W is stopped, the main transfer robot 27 takes out the processed semiconductor wafer W from the chemical cleaning unit 21 and carries it into the substrate standby reversing unit 26 . The substrate standby reversing unit 26 performs a reversing process of reversing the upper and lower surfaces of the semiconductor wafer W so that the front surface Wf is the upper surface. The semiconductor wafer W is taken out by the indexer robot 12 and carried into the carrier C. As shown in FIG.

An operation example of the substrate cleaning apparatus 1 during the sacrificial film selective removal step is as follows. That is, when the carrier C housing the semiconductor wafer W that has undergone the surface process 2 is carried into the carrier holding unit 11 , the indexer robot 12 carries it out and passes it to the substrate standby reversing unit 26 . The substrate standby reversing unit 26 performs a reversing operation of reversing the upper and lower surfaces of the semiconductor wafer W so that the back surface Wb of the semiconductor wafer W becomes the upper surface. After that, the main transfer robot 27 unloads the semiconductor wafer W and carries it into the chemical cleaning unit 21 . The chemical cleaning unit 21 performs processing for selectively removing the sacrificial film on the back surface Wb (upper surface) of the semiconductor wafer W. FIG. This processing consists of a chemical liquid process in which a chemical liquid for selectively removing the sacrificial film is supplied to the semiconductor wafer W while the semiconductor wafer W is being rotated, and a chemical liquid adhering to the semiconductor wafer W is replaced with a rinse liquid while the semiconductor wafer W is being rotated. It includes a rinsing process and a drying process (spin dry) in which the rotation of the semiconductor wafer W is accelerated to shake off the rinsing liquid adhering to the semiconductor wafer W. FIG. After such processing is completed, the main transfer robot 27 unloads the semiconductor wafer W from the chemical cleaning unit 21 and carries it into the substrate standby reversing unit 26 . The substrate standby reversing unit 26 performs a reversing process of reversing the upper and lower surfaces of the semiconductor wafer W so that the front surface Wf is the upper surface. The semiconductor wafer W is taken out by the indexer robot 12 and carried into the carrier C. As shown in FIG.

Although the embodiments of the present invention have been described above, the present invention can be implemented in other forms.

For example, substrates to be processed are not limited to semiconductor wafers, and may be other types of substrates such as flat display panel substrates and photomask substrates.

Further, in the above-described embodiments, the problems caused by the semiconductor wafer being attracted to the attraction stage of the electrostatic chuck device and the means for solving the problems were mainly described. There are similar problems and similar solutions can be applied when

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

Reference Signs List 1: substrate cleaning device 2: film forming device 3: resist coating and developing device 4: exposure device 5: dry etching device 6: carrier transfer device 10: indexer section 11: carrier holding section 12: indexer robot 15: control device 20: processing Unit 21 : Chemical washing unit 22 : Coating unit 23 : Solidification unit 23C : Cooling unit 23H : Heating unit 25 : Process section 26 : Substrate waiting and reversing unit 27 : Main transfer robot 31 : Spin chuck 33 : Processing liquid supply unit 34 : Chemical liquid Supply unit 38 : Rinse liquid supply unit 42 : Scrub unit 43 : Polishing brush 51 : Spin chuck 53 : Coating liquid supply unit 57 : Edge rinse unit 60 : Hot plate 70 : Cool plate 77 : Local transfer hand 80 : Electrostatic chuck device 81 : adsorption stage 82 : adsorption surface 83 : convex portion 91 : convex portion 92 : concave portion 93 : flat portion 96 : plastic material 97 : sacrificial film 100 : protective film 101 : convex portion 102 : concave portion 111 : support plate 112 : ultraviolet lamp C: carrier P: particle W: semiconductor wafer Wb: back surface Wf: front surface

Claims (25)

1. A method of processing a substrate having a front surface, which is a major surface exposed to form a pattern, and a back surface, which is a major surface opposite to the surface, comprising:
A planarization process for planarizing the back surface prior to exposure to form a pattern on the front surface;
The planarization process includes
a protrusion removing step of removing protrusions present on the back surface of the substrate by chemical polishing;
a concave portion filling step of filling a concave portion present on the back surface of the substrate with a fluid plastic material after the convex portion removing step;
Substrate processing method. The convex portion removing step includes:
a chemical solution supply step of supplying the chemical solution to the back surface of the substrate;
2. The substrate processing method according to claim 1, further comprising a scrubbing step of scrubbing, with a polishing brush, the back surface of said substrate to which the chemical solution has been supplied in said chemical solution supply step. The chemical solutions include hydrofluoric acid, hydrofluoric acid/hydrogen peroxide mixture, ozone-containing hydrofluoric acid solution, ammonia/hydrogen peroxide/water mixture, ozone-containing sulfuric acid solution, hydrochloric acid/hydrogen peroxide/water mixture, ozone water, and sulfuric acid/hydrogen peroxide. 3. The substrate processing method according to claim 2, comprising at least one selected from the group consisting of a mixed solution of water and aqueous hydrogen peroxide. 4. The substrate processing method according to claim 2, wherein said polishing brush has a polishing surface in which abrasive grains are contained in a brush pad bonding material. 5. The substrate processing method according to claim 4, wherein said abrasive grains include one or more of cerium, silicon carbide and diamond. 6. The substrate processing method according to claim 1, wherein said plastic material includes either a resin material, a silicon-based material, or a mixed material thereof. 7. The substrate processing method according to claim 6, wherein said resin material includes polyimide. 8. The substrate processing method of claim 6, wherein the silicon-based material includes a methyl-based silicon coating material. The substrate processing method according to any one of claims 1 to 5, wherein the plastic material comprises an organic silicon material. The recess embedding step includes:
a coating step of coating the back surface of the substrate with a fluid plastic material;
10. The substrate processing method according to any one of claims 1 to 9, further comprising a surplus material removing step of scrubbing the back surface of the substrate with a brush to remove surplus plastic material after the applying step. 11. The substrate processing method according to claim 10, further comprising a solidifying step of solidifying said plastic material after said applying step and before said excess material removing step. 12. The substrate processing method according to claim 11, wherein said solidifying step includes at least one of a baking process of heating said plastic material to 100° C. to 400° C. and an ultraviolet process of irradiating said plastic material with ultraviolet rays. a surface treatment step of treating the surface of the substrate after the recess filling step;
13. The substrate processing method according to claim 1, further comprising a removing step of removing said plastic material from the back surface of said substrate after said surface treating step. 14. The substrate processing method according to claim 13, wherein said removing step includes a step of supplying an alkaline chemical solution or an oxidant-containing chemical solution to the back surface of said substrate to dissolve said plastic material. The surface treatment step includes
a step of sucking and holding the back surface of the substrate on a suction stage;
15. The substrate processing method according to claim 13, comprising the step of pattern-exposing the surface of said substrate held by said suction stage. Before the planarization process,
16. The substrate processing method according to any one of claims 1 to 15, further comprising the step of processing the front surface of the substrate by adsorbing and holding the back surface of the substrate on an adsorption stage. A substrate processing apparatus for performing processing on a substrate having a front surface, which is a main surface on which a pattern is formed, and a back surface, which is a main surface opposite to the front surface, before performing exposure for forming the pattern. There is
a chemical polishing unit that scrubs the back surface of the substrate with a polishing brush while supplying a chemical solution to the back surface of the substrate;
a coating unit that supplies a coating liquid containing a fluid plastic material to the back surface of the substrate to form a coating film containing the plastic material. 18. The substrate processing apparatus of claim 17, further comprising a transfer robot that transfers the substrate processed by the chemical polishing unit to the coating unit. 19. The substrate processing apparatus according to claim 17, further comprising a solidification unit that processes the substrate having the coating film of the plastic material formed on the back surface thereof and solidifies the coating film. 20. The substrate processing apparatus of claim 19, wherein the solidifying unit includes at least one of a heating unit heating the substrate and an ultraviolet processing unit irradiating the substrate with ultraviolet rays. The chemical solutions include hydrofluoric acid, hydrofluoric acid/hydrogen peroxide mixture, ozone-containing hydrofluoric acid solution, ammonia/hydrogen peroxide/water mixture, ozone-containing sulfuric acid solution, hydrochloric acid/hydrogen peroxide/water mixture, ozone water, and sulfuric acid/hydrogen peroxide. 21. The substrate processing apparatus according to any one of claims 17 to 20, containing at least one selected from the group consisting of a water mixture and hydrogen peroxide water. 22. The substrate processing apparatus according to claim 17, wherein said polishing brush has a polishing surface in which abrasive grains are contained in a brush pad bonding material. 23. The substrate processing apparatus of claim 22, wherein said abrasive grains include one or more of cerium, silicon carbide and diamond. 24. The substrate processing apparatus according to any one of claims 17 to 23, wherein said plastic material includes any one of a resin material and a silicon-based material, or a mixed material thereof. The substrate processing apparatus of any one of claims 17-23, wherein the plastic material comprises an organic silicon material.

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