JP7587236B2 - Surface Treatment Equipment - Google Patents

Description

The present invention relates to a surface treatment device.

Conventionally, there is known a submerged plasma processing apparatus that generates plasma in a liquid and uses the generated plasma to process an object placed in the liquid (for example, Patent Document 1).

The in-liquid plasma processing apparatus disclosed in Patent Document 1 includes a slot antenna that radiates microwaves from a microwave generator into the liquid, and a spacer that forms a processing space between the slot antenna and the object in the liquid. The spacer defines the distance between the slot antenna and the object.

In the processing space, microwaves radiated from the slot antenna stably generate bubbles that spread in a plane. Therefore, plasma induced in the bubbles also spreads in a plane and exists stably in the area where the bubbles are generated. This makes it possible to obtain a submerged plasma processing apparatus that can efficiently plasma process a flat object placed in the processing space. The submerged plasma processing apparatus can, for example, efficiently remove a resist film provided on the surface of a semiconductor substrate.

JP 2014-127705 A

The in-liquid plasma processing apparatus disclosed in Patent Document 1 processes an object in a liquid, which is the raw material for plasma, so the object is in contact with the liquid. This requires drying equipment and a drying process to remove the liquid from the object after processing, which creates the problem of additional costs, such as the space required for the drying equipment and the time required for the drying process. There is also the problem of additional costs being incurred for equipment or an inspection process to check for the presence or absence of watermarks on the surface of the object.

Therefore, the present invention aims to provide a surface treatment device that does not require a drying process to remove liquid from the object after surface treatment.

In order to achieve the above-mentioned object, a surface treatment device according to one aspect of the present invention comprises a treatment chamber in which an object is placed, a tank placed outside the treatment chamber and storing a liquid, piping connecting the treatment chamber and the tank, through which a gas produced by vaporizing the liquid stored in the tank is introduced into the treatment chamber through the piping due to the negative pressure in the treatment chamber, a microwave generator that generates microwaves toward the object, and a slot antenna that generates plasma by passing the microwaves generated by the microwave generator and irradiating the gas in the treatment chamber.

According to this configuration, the surface treatment device treats the object with plasma generated by irradiating microwaves to the gas introduced from the tank through the piping into the treatment chamber due to the negative pressure in the treatment chamber. Here, since there is no liquid in the treatment chamber, adhesion of liquid to the object is avoided, and a drying process for removing liquid from the object after surface treatment is not required. In addition, there is an effect that equipment or an inspection process for inspecting the presence or absence of watermarks on the surface of the object is not required. Furthermore, since the device and the liquid or gas flow control device that would be required if a liquid were to be vaporized using a liquid vaporizing device are not required, the cost required for the device and the flow control device can be reduced. In addition, there is an effect that costs can be reduced by eliminating the need for a device for humidifying the inside of the piping, which is required to prevent condensation in the piping. In this way, with the surface treatment device, a drying process for removing liquid from the object after surface treatment is not required.

The piping may also be connected to the wall of the processing chamber at a position below the object.

In this configuration, in the surface treatment device, the position where the piping is connected to the treatment chamber is below the target object, so even if liquid is introduced into the treatment chamber through the piping, the liquid is prevented from adhering to the target object. Therefore, with the surface treatment device, even if liquid is introduced into the treatment chamber through the piping, a drying process for removing liquid from the target object after surface treatment is not required.

The surface treatment device may further include a member having a plurality of openings disposed between the object and the slot antenna.

With this configuration, the arrangement of the member having multiple openings reduces the amount of the microwaves and charged particle flux that constitutes the plasma that passes through the member and reaches the target object. This allows the target object to be preferentially surface-treated with uncharged, electrically neutral, chemically active species (radicals). In areas with high radical density, the density is reduced due to deactivation caused by recombination, etc., and the radicals diffuse freely without being affected by electromagnetic fields, so that differences in the strength of the treatment applied to the target object due to position are suppressed. In this way, the surface treatment device can make the strength of the treatment applied to the target object uniform, and does not require a drying process to remove liquid from the target object after surface treatment.

A surface treatment device according to one aspect of the present invention includes a treatment chamber in which an object is placed, a microwave generator that generates microwaves toward the object, a slot antenna that generates plasma by passing the microwaves generated by the microwave generator and irradiating the gas in the treatment chamber, and a member with multiple openings that is placed between the object and the slot antenna.

With this configuration, the surface treatment device reduces the amount of the microwaves and charged particle flux that constitutes the plasma that passes through the member and reaches the target object by arranging a member having multiple openings. This makes the density of the charged particles that constitute the plasma uniform in a plane perpendicular to the direction of microwave irradiation, and also slows down the speed of the charged particles. This reduces the difference in the intensity of the treatment applied to the target object due to position. In addition, by reducing the charged particle flux irradiated to the target object by the mesh member and making the radical reaction dominant, the difference in the intensity of the treatment applied to the target object due to position is reduced. In this way, with the surface treatment device, the intensity of the treatment applied to the target object is uniform, and a drying process for removing liquid from the target object after surface treatment is not required.

The slot antenna may also have a conductive plate and a first slit provided in the plate, and the first slit may have a first linear opening provided in the plate, a second opening provided in the plate and connected to the first opening at one end of the first opening, and a third opening provided in the plate and connected to the first opening at the other end of the first opening.

With this configuration, the surface treatment device uses the slot antenna to generate plasma with a shape that has a relatively large width in the left-right direction. Then, the object is treated with this plasma, so the surface treatment device can perform uniform plasma treatment on a relatively wide area of the object. Therefore, the surface treatment device can perform uniform plasma treatment on a relatively wide area of the object, and further, a drying process for removing liquid from the object after surface treatment is not required.

The slot antenna may further include a second slit provided on the plate and spaced apart from the first slit.

The surface treatment device can generate plasma over a relatively wide area by irradiating microwaves through two spaced slits, thereby reducing differences in the strength of the treatment applied to the object depending on the position. In this way, the surface treatment device can homogenize the strength of the treatment applied to the object, while eliminating the need for a drying process to remove liquid from the object after surface treatment.

The second slit may also have a fourth linear opening provided in the plate body, the fourth opening being parallel to the first opening, a fifth opening provided in the plate body, the fifth opening being connected to the fourth opening at one end of the fourth opening, and a sixth opening provided in the plate body, the sixth opening being connected to the fourth opening at the other end of the fourth opening.

With this configuration, the surface treatment device uses a slot antenna with two spaced slits to generate plasma with a shape having a larger width in a plane perpendicular to the direction of microwave irradiation, and can perform uniform plasma treatment on a wider area of the object. Therefore, the surface treatment device can perform uniform plasma treatment on a relatively wide area of the object, and further, a drying process for removing liquid from the object after surface treatment is not required.

The second opening may be connected to the first opening at one of both ends of the second opening that is closer to the fourth opening, the third opening may be connected to the first opening at one of both ends of the third opening that is closer to the fourth opening, the fifth opening may be connected to the fourth opening at one of both ends of the fifth opening that is closer to the first opening, and the sixth opening may be connected to the fourth opening at one of both ends of the sixth opening that is closer to the first opening.

With this configuration, the surface treatment device uses a slot antenna with two spaced apart U-shaped slits to generate plasma with a shape having a larger width in a plane perpendicular to the direction of microwave irradiation, and can perform uniform plasma treatment on a wider area of the object. Therefore, the surface treatment device can perform uniform plasma treatment on a relatively wide area of the object, and further, a drying process for removing liquid from the object after surface treatment is not required.

The member having the multiple openings may also be a conductive mesh member or a punched plate.

With this configuration, the arrangement of the conductive mesh member or punching plate further reduces the amount of microwaves and charged particle fluxes that constitute the plasma that pass through the mesh and reach the target object. This allows the target object to be preferentially surface-treated with uncharged, electrically neutral, chemically active species (radicals). In areas with high radical density, the density is reduced due to deactivation caused by recombination, etc., and the radicals diffuse freely without being affected by electromagnetic fields, so that differences in the strength of the treatment applied to the target object due to position are suppressed. In this way, the surface treatment device can uniformize the strength of the treatment applied to the target object, and does not require a drying process to remove liquid from the target object after surface treatment.

In addition, the member having the multiple openings may not have electrical connection to other conductive members.

With this configuration, the surface treatment device has a stable potential for the mesh member because the mesh member is electrically disconnected from other conductive members, and plasma can be generated stably. Therefore, with the surface treatment device, the object can be treated with stably generated plasma, and a drying process for removing liquid from the object after surface treatment is not required.

The object may be a substrate coated with resist, the gas may be water vapor produced by vaporizing ultrapure water, and the surface treatment device may remove the resist from the object by using plasma generated by irradiating the water vapor with the microwaves.

With this configuration, the surface treatment device can perform resist removal processing as a surface treatment in the manufacture of semiconductor devices. Therefore, the surface treatment device does not require a drying process to remove liquid from the target object after the resist removal processing.

The plasma processing apparatus according to this aspect of the present invention does not require a drying process to remove liquid from the object after surface treatment.

1 is a schematic diagram showing an example of a configuration of a surface treatment apparatus according to an embodiment; FIG. 2 is an enlarged view of the configuration within a frame II in FIG. 1 . FIG. 1 is a schematic diagram showing a first example of a slot antenna according to an embodiment. FIG. 11 is a schematic diagram showing a second example of a slot antenna according to an embodiment. FIG. 13 is a schematic diagram showing a third example of a slot antenna according to an embodiment. FIG. 13 is a schematic diagram showing a fourth example of a slot antenna according to an embodiment. FIG. 13 is a schematic diagram showing a fifth example of a slot antenna according to an embodiment. FIG. 2 is a schematic diagram showing a first example of a mesh member according to an embodiment. FIG. 11 is a schematic diagram showing a second example of a mesh member according to an embodiment. 1A to 1C are explanatory diagrams showing examples of results of surface treatment performed by a surface treatment device according to a related art and an embodiment; 1A to 1C are first explanatory diagrams showing examples of evaluation results of the uniformity of surface treatment performed by the surface treatment apparatus according to the embodiment; FIG. 11 is a second explanatory diagram showing an example of the evaluation result of the uniformity of the surface treatment performed by the surface treatment apparatus according to the embodiment. FIG. 11 is a third explanatory diagram showing an example of an evaluation result of the uniformity of the surface treatment performed by the surface treatment apparatus according to the embodiment.

The surface treatment device according to the embodiment of the present invention will be described in detail below with reference to the drawings.

The embodiment described below shows one specific example of the present invention. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiment are merely examples and are not intended to limit the present invention. Furthermore, among the components in the following embodiment, those components that are not described in an independent claim that shows the highest concept are described as optional components.

(Embodiment)
In this embodiment, a surface treatment apparatus that does not require a drying step for removing liquid from an object after surface treatment will be described.

Figure 1 is a schematic diagram showing an example of the configuration of a surface treatment device according to this embodiment. Figure 2 is an enlarged view of the configuration within frame II in Figure 1. Figures 1 and 2 show the posture of the surface treatment device when in use. Note that the illustrated XYZ axes may also be used for explanation. The positive direction of the Z axis is also referred to as the down or downward direction, and the negative direction of the Z axis is also referred to as the up or upward direction.

The surface treatment device 10 shown in Figures 1 and 2 is a device that performs plasma treatment on the surface of an object 80, that is, the upper surface in Figures 1 and 2. The surface treatment device 10 includes a microwave generator 11, a waveguide 12, a microwave-transparent member 13, a container 14, a slot antenna 15, a mesh member 16, a spacer 17, a holder 18, a pipe 20, and a tank 21.

The microwave generator 11 is a device that generates pulse-modulated microwaves. The microwave generator 11 generates microwaves using a magnetron or a semiconductor, and outputs the microwaves via the waveguide 12 toward the object 80 in the processing chamber S1.

The waveguide 12 is a tapered waveguide that propagates the microwaves output from the microwave generator 11. A microwave-transparent member 13 is provided inside the waveguide 12. The microwave-transparent member 13 may be formed of, for example, quartz.

The container 14 is a container having a processing chamber S1 inside. An object 80 is placed in the processing chamber S1. The container 14 is formed of, for example, acrylic resin. The tip of the waveguide 12 is connected to the top surface of the container 14. In addition, a pipe 20 is connected to the side wall of the container 14, and a tank 21 is further connected via the pipe 20.

The container 14 also has an exhaust port 141. The processing chamber S1 in the container 14 is depressurized by an air pump (not shown) connected to the exhaust port 141, so that the pressure inside the container 14 becomes negative.

The slot antenna 15 is an antenna that radiates microwaves propagated from the microwave generator 11 through the waveguide 12 and the microwave-transmitting member 13 to the processing chamber S1. The slot antenna 15 is disposed at the tip of the waveguide 12 in the processing chamber S1. The slot antenna 15 is formed of a conductive plate and has a slit 151 that allows microwaves to pass through. The microwaves that pass through the slot antenna 15 are irradiated to the gas present below the slot antenna 15 to generate plasma (surface wave plasma). The material of the slot antenna 15 is a conductive substance, such as silicon or copper. However, when a resist removal process for a substrate is assumed as the surface treatment, the material of the slot antenna 15 is, for example, silicon. This is because copper may cause impurities in the substrate.

The slit 151 is a long and narrow opening, in other words a gap or void, provided in a conductive plate. The slit 151 is formed, for example, by wire cutting. The shape of the slit 151 will be described in detail later.

The mesh member 16 is a conductive mesh member. The mesh member 16 is placed between the object 80 and the slot antenna 15, and is fixed at a position 4 mm downward from the slot antenna 15, for example. The mesh member 16 is an example of a member having multiple openings. Here, an example will be described in which the mesh member 16 is used as a member having multiple openings, but a punching plate may also be used. The mesh member 16 is not a required component.

The mesh member 16 may or may not be conductive.

If the mesh member 16 is conductive, it may not be electrically connected to other conductive members. The material of the mesh member 16 is, for example, anodized aluminum or stainless steel. The wire diameter of the mesh member 16 is, for example, 0.11 mm, and the number of meshes is, for example, #20 mesh or #30 mesh, but is not limited to these. The wire diameter, number of meshes, or material of the mesh member 16 may be uniform throughout the entire mesh member 16, or may vary depending on the position.

The mesh member 16 has the effect of blocking microwaves that have passed through the slot antenna 15. In other words, the mesh member 16 has the effect of reducing the amount of microwaves that have passed through the slot antenna 15 and reach the target object 80. This microwave blocking effect is exerted even if the surface of the mesh member 16 is anodized, as long as the inside of the coating is conductive.

The mesh member 16 adjusts the intensity of the plasma 19 generated by the microwaves that have passed through the slot antenna 15. Specifically, the mesh member 16 has the effect of uniforming the density of the plasma 19 in the XY plane, and as a result, the intensity of the plasma processing on the surface of the object 80 can be uniformed. This effect of uniforming the density of the plasma 19 is exerted whether the mesh member 16 is conductive or not.

The spacer 17 determines the distance between the slot antenna 15 and the mesh member 16 and the target object 80.

The holder 18 is a member that is fixed in the processing chamber S1 and holds the object 80. For example, the holder 18 holds the object 80 from vertically below. The object 80 is held at a position that is, for example, 9 mm below the slot antenna 15.

The piping 20 connects the processing chamber S1 (container 14) and the tank 21. The piping 20 connects the processing chamber S1 and the tank 21. The piping 20 may be made of a material with a fixed shape, such as metal or resin, or may be made of a flexible material, such as rubber.

The tank 21 is a tank that stores a liquid that is a raw material for plasma. The tank 21 is placed outside the processing chamber S1 and is connected to the processing chamber S1 inside the container 14 via piping 20. The air pressure inside the tank 21 is approximately the same as inside the processing chamber S1 that is connected to it by piping 20, and the liquid 81 vaporizes inside the tank 21 to generate a gas. The liquid 81 is, for example, ultrapure water or ethanol.

In the surface treatment device 10 configured in this manner, the gas generated by vaporizing the liquid 81 stored in the tank 21 is introduced into the treatment chamber S1 through the piping 20 due to the negative pressure in the treatment chamber S1. The gas introduced into the treatment chamber S1 is ionized by microwaves passing through the slot antenna 15 to generate plasma 19. The surface of the object 80 is treated by the generated plasma 19.

Note that although the plasma 19 is illustrated in Figures 1 and 2 as being located between the object 80 and the mesh member 16, some of the plasma 19 may reach below the mesh member 16.

That is, charged particles and radicals that constitute plasma 19 are generated in the space between slot antenna 15 and mesh member 16. The density of the generated charged particles and radicals is higher near slit 151, i.e., the center of slot antenna 15. Here, mesh member 16 acts as a potential wall for the charged particles. Mesh member 16 also has the effect of decelerating the charged particles. Therefore, the presence of mesh member 16 prevents the charged particles from moving into the space below mesh member 16. Note that radicals, which are electrically neutral, are thought to reach below mesh member 16 without being significantly affected by mesh member 16. In this way, it is thought that part of plasma 19 reaches below mesh member 16.

The position where the piping 20 is connected to the processing chamber S1 (container 14) may be any position on the wall of the processing chamber S1, but may also be connected at a position below the target object 80 when in use. If the piping 20 is connected at such a position, even if a small amount of liquid 81 is introduced into the processing chamber S1 through the piping 20, the liquid 81 can be prevented from adhering to the target object 80.

An example of the object 80 is a substrate covered with resist. The liquid 81 is ultrapure water. In this case, the surface treatment device 10 functions as a resist removal device (resist asher) that removes resist from the object 80 by radicals generated by irradiating microwaves to water vapor generated by vaporization of the ultrapure water, which is the liquid 81. At this time, the air pressure in the treatment chamber S1 is, for example, about 3 kPa. Since the saturated vapor pressure of water is about 2.5 kPa at room temperature, the proportion of water vapor in the gas in the treatment chamber S1 can be relatively increased by lowering the air pressure in the treatment chamber S1 to about 3 kPa, which contributes to the generation of high-density plasma. Hydrogen peroxide can also be used as the liquid 81.

If the tank 21 is located outside the processing chamber S1 and in a position where it is not irradiated with microwaves generated by the microwave generator 11, vaporization of the liquid 81 caused by microwave irradiation is suppressed, which can contribute to stabilizing the air pressure in the processing chamber S1. If microwaves are irradiated to the liquid 81, vaporization of the liquid 81 is promoted, causing the air pressure in the processing chamber S1 to fluctuate, which may cause a change in the speed of plasma processing of the target object 80 by the plasma 19 or a change in the characteristics of the plasma processing.

In this way, gas is introduced into the processing chamber S1 through the piping 20; in other words, no liquid 81 is present. This makes it possible to prevent the liquid 81 from adhering to the object 80, which has the advantage that there is no need to detect and process the watermark after processing the object 80.

The slot antenna 15 will be explained in more detail below.

Figure 3 is a schematic diagram showing a first example of a slot antenna 15 according to this embodiment.

As shown in FIG. 3, the slot antenna 15 has three linear openings (gaps) as the slit 151: a first opening 151A, a second opening 151B, and a third opening 151C. The linear openings can also be considered as elongated rectangular openings.

The first opening 151A is connected at both ends to the second opening 151B and the third opening 151C.

The second opening 151B is connected to the first opening 151A at one end of the first opening 151A. The angle between the second opening 151B and the first opening 151A is, for example, 90 degrees or within a range of 90 degrees plus or minus 10 degrees, but is not limited to this.

The third opening 151C is connected to the first opening 151A at the other end of the first opening 151A. The angle between the third opening 151C and the first opening 151A is, for example, 90 degrees or within a range of 90 degrees plus or minus 10 degrees, but is not limited to this.

For example, when the microwave frequency is 2.45 GHz and the material of the waveguide for sealing the vacuum is quartz, the width L1 of the first opening 151A is about several mm, and the length L2 is, for example, about several cm. The width L3 of the second opening 151B and the third opening 151C is, for example, about several mm, and the length L4 is, for example, about several cm. These dimensions can be determined by the frequency of the microwaves (electromagnetic waves) or the dielectric constant of the medium that propagates the microwaves.

By using such a slot antenna 15, it is possible to generate plasma 19 that is relatively close to a circle in the XY plane. If a slot antenna with only one linear opening were used, plasma that is linear or elliptical in the XY plane would be generated. Plasma of this shape is not suitable for processing an object 80 that extends in the X and Y directions. In contrast, plasma 19 that is relatively close to a circle in the XY plane as described above is suitable for processing an object 80 that extends in the X and Y directions.

Figure 4 is a schematic diagram showing a second example of a slot antenna 15 according to this embodiment.

The slot antenna 15 shown in FIG. 4 is the slot antenna 15 shown in FIG. 3 with the widths of the first opening 151A, the second opening 151B, and the third opening 151C changed.

The slot antenna 15 shown in FIG. 4 has three linear openings (gaps) as the slit 152: a first opening 152A, a second opening 152B, and a third opening 152C. The connection relationship of these openings is the same as in the slit 151 (see FIG. 3).

The width M1 of the first opening 152A is smaller than the width L1 of the first opening 151A (see FIG. 3). The width M3 of the second opening 152B is larger than the width L3 of the second opening 151B (see FIG. 3). In this way, by varying the width of the openings, the shape of the generated plasma 19 in the XY plane can be adjusted. In particular, as shown in FIG. 4, by increasing the width of the second opening 152B and the third opening 152C, it is possible to generate plasma 19 with a shape that is closer to a circle in the XY plane, and to effectively process the object 80 that has an extension in the X and Y directions.

The shape of the generated plasma 19 in the XY plane can also be adjusted by making the length M2 of the first opening 152A larger or smaller than the length L2 of the first opening 151A (see FIG. 3) or by making the length M4 of the second opening 152B larger or smaller than the length L4 of the second opening 151B (see FIG. 3).

Figure 5 is a schematic diagram showing a third example of a slot antenna 15 according to this embodiment.

The slot antenna 15 shown in FIG. 5 is a slot antenna 15 shown in FIG. 3 with the second opening 151B and the third opening 151C having different shapes.

The slot antenna 15 shown in FIG. 5 has three openings (gaps) as the slit 153: a first opening 153A, a second opening 153B, and a third opening 153C. The connection relationship of these openings is the same as in the slit 151 (see FIG. 3).

Second opening 153B has a pentagonal shape, whereas second opening 151B and second opening 152B have a rectangular shape. The same is true for third opening 153C.

In this way, the second opening 153B or the third opening 153C does not necessarily have to be rectangular, but may be a polygon, or may be a figure that is partially or entirely curved. In addition, the second opening 153B and the third opening 153C do not have to be the same shape.

The first opening 153A is rectangular, but as described above, it may be polygonal or may be a shape that is partially or entirely curved.

In this way, the shape of the opening can be adjusted in the XY plane by changing the shape of the opening to a polygon or a figure including curves.

Figure 6 is a schematic diagram showing a fourth example of a slot antenna 15 according to this embodiment.

The slot antenna 15 shown in FIG. 6 has two slits 152 as shown in FIG. 4. For ease of explanation, the two slits 152 of the slot antenna 15 shown in FIG. 6 are referred to as slits 154P and 154Q.

The slit 154P has a first opening 154A, a second opening 154B, and a third opening 154C. The slit 154Q has a fourth opening 154D, a fifth opening 154E, and a sixth opening 154F.

Slits 154P and 154Q are spaced apart.

The fourth opening 154D of the slit 154Q is illustrated as being parallel to the first opening 154A of the slit 154P as an example, but is not limited to this. Note that the term "parallel" does not only refer to being strictly parallel, but also includes being within a range that is considered to be substantially parallel (for example, an angle of about 10 degrees or 20 degrees or less). The same applies hereinafter.

In addition, the fifth opening 154E of the slit 154Q is shown as being located on an extension of the second opening 154B of the slit 154P, but they may be parallel, and are not limited to the above.

In addition, the sixth opening 154F of the slit 154Q is shown as being located on an extension of the third opening 154C of the slit 154P, but they may be parallel, and are not limited to the above.

The slot antenna 15 with slits 154P and 154Q shown in FIG. 6 allows the shape of the generated plasma 19 in the XY plane to be adjusted. More specifically, the slot antenna 15 with slits 154P and 154Q allows the generation of plasma 19 with a shape closer to a circle in the XY plane, allowing effective processing of the object 80 that has an extension in the X and Y directions.

Figure 7 is a schematic diagram showing a fifth example of a slot antenna 15 according to this embodiment.

The slot antenna 15 shown in FIG. 7 has two slits similar to the slit 152 shown in FIG. 4. For ease of explanation, the two slits 152 of the slot antenna 15 shown in FIG. 7 are referred to as slits 155P and 155Q.

Similar to slits 154P and 154Q shown in FIG. 6, slit 155P includes a first opening 155A, a second opening 155B, and a third opening 155C. Slit 155Q includes a fourth opening 155D, a fifth opening 155E, and a sixth opening 155F. Slits 155P and 155Q are spaced apart.

Furthermore, as with slits 154P and 154Q shown in FIG. 6, the fourth opening 155D of slit 155Q is illustrated as being parallel to the first opening 155A of slit 155P, but this is not limited to this. The fifth opening 155E of slit 155Q is illustrated as being located on an extension of the second opening 155B of slit 155P, but these may be parallel, and this is not limited to this. The sixth opening 155F of slit 155Q is illustrated as being located on an extension of the third opening 155C of slit 155P, but these may be parallel, and this is not limited to this.

Furthermore, as shown in FIG. 7, the second opening 155B is connected to the first opening 155A at the end of the second opening 155B that is closer to the fourth opening 155D. The third opening 155C is connected to the first opening 155A at the end of the third opening 155C that is closer to the fourth opening 155D. The fifth opening 155E is connected to the fourth opening 155D at the end of the fifth opening 155E that is closer to the first opening 155A. The sixth opening 155F is connected to the fourth opening 155D at the end of the sixth opening 155F that is closer to the first opening 155A.

The slot antenna 15 with slits 155P and 155Q shown in FIG. 7 allows adjustment of the shape of the generated plasma 19 in the XY plane. More specifically, the slot antenna 15 with slits 155P and 155Q allows generation of plasma 19 with a shape closer to a circle in the XY plane, allowing effective processing of the object 80 that has an extension in the X and Y directions.

Figure 8 is a schematic diagram showing a first example of a mesh member 16 according to this embodiment.

The mesh member 16 shown in FIG. 8 is a mesh member having a uniform mesh throughout the entire XY plane. Note that, although the mesh member 16 is shown to have a rectangular outer shape as an example, it may have any shape as long as it can be held by the spacer 17.

Figure 9 is a schematic diagram showing a second example (mesh member 16A) of the mesh member 16 according to this embodiment.

The mesh member 16A shown in FIG. 9 is an example of a mesh member in which the number of meshes varies depending on the position in the XY plane.

That is, mesh member 16A has mesh member 16B in its center, which has a larger number of meshes than the number of meshes in the peripheral area.

As described above, the density of plasma 19 in the XY plane is greater in the vicinity of slit 151, i.e., in the central area, than in the peripheral area. Therefore, by increasing the number of meshes in mesh member 16 near slit 151, i.e., closer to the central area, the effect of uniforming the distribution of charged particles and slowing them down in the central area can be increased. In this way, by having different numbers of meshes depending on the position of mesh member 16A, the density or shape of plasma 19 can be adjusted.

Mesh member 16A is an example of a mesh member in which the number of mesh holes varies depending on the position in the XY plane, but similarly, it is also possible to employ a mesh member in which the mesh line diameter varies depending on the position in the XY plane, or in which the mesh material varies depending on the position in the XY plane.

Figure 10 is an explanatory diagram showing an example of the results of surface treatment by the surface treatment device 10 according to the related art and the present embodiment. With reference to Figure 10, the effects of the slot antenna 15 and mesh member 16 provided in the surface treatment device 10 will be considered.

Figure 10 shows the results of measuring the speed (ashing rate) of the ashing process, which is an example of plasma processing, to remove a resist film provided on the surface of a semiconductor substrate, which is the target object 80. The density of the generated plasma in the XY plane can be inferred from the distribution of the magnitude of the ashing process speed in the XY plane.

In (a) to (d) of FIG. 10, the frequency of the microwaves generated by the microwave generator 11 is 2.45 GHz, the microwaves are square-wave modulated, and the peak power is 200 W. The square-wave modulation frequency is 100 Hz, and the on-duty factor is 30%. The air pressure in the processing chamber S1 is 3 kPa.

On the left side of the paper in (a) to (d) of Figure 10, the areas where the ashing speed for each position of the object 80 is relatively high are shown in a color closer to white, and the areas where the ashing speed is relatively low are shown in a color closer to black.

The positional relationship between the target object 80 and the slot antenna as viewed from a direction perpendicular to the Z axis is also shown at the center of the left-right direction on the paper of (a) to (d) of Figure 10. If the surface treatment device is equipped with a mesh, the mesh is also shown.

The right side of the paper in Figure 10 (a) to (d) shows a schematic diagram of the shape of the slot antenna as viewed from the positive direction of the Z axis.

Figure 10 (a) is an explanatory diagram showing the results of surface treatment by a surface treatment device according to the related art. Figure 10 (a) shows the results of surface treatment by a surface treatment device in which the distance between the slot antenna and the object 80 is 3.5 mm and there is no mesh member between the slot antenna and the object 80. The slot antenna has only a linear slit.

In the results shown in Figure 10(a), the area with relatively high processing speed has an elliptical shape.

This is thought to be due in part to the fact that the slits in the slot antenna are linear, causing the plasma generated to have an elliptical shape that is slightly wider than a straight line in the XY plane.

Figure 10(b) is an explanatory diagram showing the result of surface treatment by the surface treatment device 10 according to this embodiment. Figure 10(b) shows the result of surface treatment by the surface treatment device 10 in which the separation distance between the slot antenna 15 and the object 80 is 3.5 mm and there is no mesh member 16 between the slot antenna 15 and the object 80.

In the results shown in Figure 10(b), the shape of the area with relatively fast processing speed is closer to a circle compared to Figure 10(a).

In this way, by using the slot antenna 15, the processing area of the target object 80 can be expanded to a shape close to a circle. This is thought to be due in part to the fact that the slot antenna 15 is able to make the density of the plasma 19 more uniform in the XY plane than a slot antenna that has only a linear slit (see FIG. 10(a)).

Figure 10 (c) is an explanatory diagram showing the result of surface treatment by the surface treatment device 10 according to this embodiment. Figure 10 (c) shows the result of surface treatment by the surface treatment device 10 in which the separation distance between the slot antenna 15 and the object 80 is 9.0 mm and there is no mesh member 16 between the slot antenna 15 and the object 80.

In the results shown in FIG. 10(c), the difference between areas with a large amount of surface treatment and areas with a small amount of surface treatment is smaller than in FIG. 10(b). In other words, the amount of surface treatment is uniform within the XY plane.

In this way, by increasing the distance between the slot antenna 15 and the object 80, the amount of processing on the object 80 can be made uniform. It is believed that one reason for this is that the action of the plasma 19 on the object 80 is made more uniform when the distance between the slot antenna 15 and the object 80 is larger.

Figure 10(d) is an explanatory diagram showing the results of surface treatment by the surface treatment device 10 according to this embodiment. Figure 10(d) shows the results of surface treatment by the surface treatment device 10 in which the separation distance between the slot antenna 15 and the object 80 is 9.0 mm and there is a mesh member 16 between the slot antenna 15 and the object 80.

In the results shown in FIG. 10(d), the difference between areas with a large amount of surface treatment and areas with a small amount of surface treatment is smaller than in FIG. 10(c). In other words, the amount of surface treatment is more uniform within the XY plane.

In this way, the presence of the mesh member 16 between the slot antenna 15 and the object 80 makes it possible to make the processing amount on the object 80 even more uniform. It is believed that one of the reasons for this is that the mesh member 16 makes the density of the plasma 19 uniform in the XY plane.

Next, we will explain the evaluation results of the uniformity of surface treatment using the surface treatment device 10 equipped with the slot antenna 15 shown in Figures 4, 6, and 7.

Figure 11 is a first explanatory diagram showing an example of the evaluation results of the uniformity of surface treatment by the surface treatment apparatus 10 according to this embodiment. More specifically, Figure 11 shows the evaluation results of the electric field intensity distribution and ashing rate in the XY plane at a position 6.3 mm in the positive direction of the Z axis from the slot antenna 15, for plasma 19 generated using a slot antenna 15 (see (a)) having a slit 152. The uniformity shown below is used as an evaluation index for the ashing rate.

Uniformity (%) = (maximum value - minimum value) / (2 x average value)

Here, the maximum, minimum, and average values are the maximum, minimum, and average values of the ashing rate in the XY plane, respectively.

As shown in FIG. 11(b), the electric field strength distribution is relatively high at the center in the XY plane and decreases the farther away from the center. The maximum value of the electric field strength is 944 V/m.

As shown in FIG. 11(c), the ashing rate is relatively high at the center in the XY plane, similar to the electric field intensity distribution, and decreases the farther from the center. The uniformity of the ashing rate is 30.00% (see (d)).

Figure 12 is a second explanatory diagram showing an example of the evaluation results of the uniformity of surface treatment by the surface treatment device 10 according to this embodiment. More specifically, Figure 12 shows the evaluation results of the electric field intensity distribution and the ashing rate measured under the same conditions as in Figure 11 using a slot antenna 15 (see (a)) having slits 154P and 154Q.

As shown in FIG. 12(b), the electric field strength distribution is relatively high at positions located a certain distance from the center in the positive and negative Y-axis directions in the XY plane, and decreases the further away from the center. The area where the electric field strength is relatively high has a gourd shape that is long in the Y-axis direction. The maximum electric field strength is 875 V/m.

As shown in FIG. 12(c), the ashing rate is relatively high at positions in the XY plane that are a certain distance from the center in both the positive and negative Y-axis directions, and decreases the further away from the center. The uniformity of the ashing rate is 18.12% (see (d)).

Figure 13 is a third explanatory diagram showing an example of the evaluation results of the uniformity of surface treatment by the surface treatment device 10 according to this embodiment. More specifically, Figure 13 shows the evaluation results of the electric field intensity distribution and ashing rate measured under the same conditions as in Figure 11 using a slot antenna 15 having the shape shown in Figure 7 (see (a)).

As shown in FIG. 13(b), the electric field strength distribution is relatively high at positions located a certain distance from the center in the positive and negative Y-axis directions in the XY plane, and decreases the further away from the center. The shape of the part where the electric field strength is relatively high is an ellipse that is long in the Y-axis direction. The maximum value of the electric field strength is 956 V/m.

As shown in FIG. 13(c), the ashing rate is relatively high at the center in the XY plane and decreases away from the center. The uniformity of the ashing rate is 14.66% (see (d)).

As described above, the surface treatment by the slot antenna 15 having slits 154P and 154Q is more uniform than the surface treatment by the slot antenna 15 having slits 152, and furthermore, the surface treatment by the slot antenna 15 having slits 155P and 155Q is more uniform.

Note that there exists a processing apparatus having a different configuration from the above-mentioned surface processing apparatus 10, which has two opposing electrodes in a processing chamber and generates a high frequency (approximately 13 MHz or 27 MHz) between the electrodes to turn a gas into plasma. In such an apparatus, it is known that the energy of the ions contained in the plasma becomes greater than necessary, causing significant damage to the target object 80.

Compared to such devices, the above-mentioned surface treatment device 10 can generate plasma by passing microwaves through the slot antenna 15, and has the advantage that the energy of the ions contained in the plasma is relatively small, minimizing damage to the target object 80.

The above describes the surface treatment device according to one or more aspects of the present invention based on the embodiment, but the present invention is not limited to this embodiment. As long as it does not deviate from the spirit of the present invention, various modifications that a person skilled in the art may make to this embodiment, or a form constructed by combining components of different embodiments, may also be included within the scope of one or more aspects of the present invention.

In the embodiment, the application of the surface treatment device to a resist removal device has been described as an example, but the surface treatment device is not limited to a resist removal device and can be widely used in devices that perform various surface treatments that are suitable for plasma treatment. For example, it can be used in a surface modification device that makes the surface of an object hydrophilic, or a film formation device that forms a graphene film on the surface of an object using an organic liquid (e.g., ethanol, methanol, etc.).

The present invention can be widely used as a surface treatment device for performing various types of surface treatment that are suitable for plasma treatment.

REFERENCE SIGNS LIST 10 Surface treatment device 11 Microwave generator 12 Waveguide 13 Microwave-transmitting member 14 Container 15 Slot antenna 16, 16A, 16B Mesh member 17 Spacer 18 Holder 19 Plasma 20 Pipe 21 Tank 80 Object 81 Liquid 141 Exhaust port 151, 152, 153, 154P, 154Q, 155P, 155Q Slit 151A, 152A, 153A, 154A, 155A First opening 151B, 152B, 153B, 154B, 155B Second opening 151C, 152C, 153C, 154C, 155C Third opening 154D, 155D Fourth opening 154E, 155E Fifth opening 154F, 155F Sixth opening S1 Processing chamber

Claims (11)

a processing chamber within which the object is placed;
a tank disposed outside the processing chamber and storing a liquid;
a pipe connecting the processing chamber and the tank, the pipe being configured so that a gas generated by vaporizing a liquid stored in the tank is introduced into the processing chamber through the pipe by a negative pressure in the processing chamber;
a microwave generator that generates microwaves toward the target;
a slot antenna that generates plasma by passing microwaves generated by the microwave generator and irradiating the gas in the processing chamber;
The piping is connected to a wall of the processing chamber at a position below the object. The surface treatment device further comprises:
The surface treatment apparatus according to claim 1 , further comprising a member having a plurality of openings, the member being disposed between the object and the slot antenna. The slot antenna is
A conductive plate;
A first slit is provided in the plate body,
The first slit is
A linear first opening provided in the plate;
A second opening provided in the plate body, the second opening being connected to the first opening at one end of the first opening;
The surface treatment device according to claim 1 or 2, further comprising a third opening provided in the plate, the third opening being connected to the first opening at the other end of the first opening. The slot antenna further comprises:
The surface treatment device according to claim 3 , further comprising a second slit provided on the plate and spaced apart from the first slit. The second slit is
a fourth linear opening provided in the plate and parallel to the first opening;
a fifth opening provided in the plate body, the fifth opening being connected to the fourth opening at one end of the fourth opening;
The surface treatment device according to claim 4 , further comprising a sixth opening provided in the plate, the sixth opening being connected to the fourth opening at the other end of the fourth opening. The second opening is connected to the first opening at an end of the second opening that is closer to the fourth opening,
The third opening is connected to the first opening at an end portion of the third opening that is closer to the fourth opening,
The fifth opening is connected to the fourth opening at an end closer to the first opening, of both ends of the fifth opening;
The surface treatment device according to claim 5 , wherein the sixth opening is connected to the fourth opening at one of both ends of the sixth opening that is closer to the first opening. The surface treatment device according to claim 2 , wherein the member having the plurality of openings is a conductive mesh member or a punched plate. The surface treatment device of claim 7 , wherein the member having the plurality of openings is not electrically connected to other conductive members. the object is a substrate coated with a resist;
the gas is water vapor produced by vaporization of ultrapure water,
The surface treatment apparatus according to any one of claims 1 to 8, wherein the surface treatment apparatus removes the resist from the object by using plasma generated by irradiating the water vapor with the microwaves. a processing chamber within which the object is placed;
a tank disposed outside the processing chamber and storing a liquid;
a pipe connecting the processing chamber and the tank, the pipe being configured so that a gas generated by vaporizing a liquid stored in the tank is introduced into the processing chamber through the pipe by a negative pressure in the processing chamber;
a microwave generator that generates microwaves toward the target;
a slot antenna that passes the microwaves generated by the microwave generator and irradiates the gas in the processing chamber to generate plasma ;
a waveguide for guiding the microwaves generated by the microwave generator to the target, the waveguide having the slot antenna at an end of the waveguide closer to the target ,
The slot antenna is
A conductive plate;
A first slit is provided in the plate body,
The first slit is
A linear first opening provided in the plate;
A second opening provided in the plate body, the second opening being connected to the first opening at one end of the first opening;
a third opening provided on the plate, the third opening being connected to the first opening at the other end of the first opening. The slot antenna further comprises:
A second slit is provided in the plate body and spaced apart from the first slit,
The second slit is
A fourth opening portion is provided in the plate body and is linear, the fourth opening portion being arranged in a direction perpendicular to the longitudinal direction of the first opening portion and parallel to the first opening portion;
a fifth opening provided in the plate body, the fifth opening being connected to the fourth opening at one end of the fourth opening;
a sixth opening provided in the plate body, the sixth opening being connected to the fourth opening at the other end of the fourth opening;
The surface treatment device according to claim 10.

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