KR20060123394A - Apparatuses and methods for cleaning a substrate - Google Patents

Abstract

An apparatus for use in processing a substrate (216) includes a brush enclosure (212) extending over a length. The brush enclosure (212) is configured to be disposed over a surface of the substrate (216) and has an open region that is configured to be disposed in proximity to the substrate (216). The open region extends over the length of the brush enclosure (212) and enables foam (410) from within the brush enclosure (212) to contact the surface of the substrate (216). A substrate cleaning system and method for cleaning a substrate are also described.

Description

Substrate cleaning apparatus and method {APPARATUSES AND METHODS FOR CLEANING A SUBSTRATE}

Background of the Invention

Field of invention

TECHNICAL FIELD The present invention relates to semiconductor manufacturing, and more particularly, to an apparatus and method used to process a substrate.

Description of the related technology

In the manufacture of semiconductor devices, it is necessary to perform substrate (eg semiconductor wafer) cleaning. For example, the process of manufacturing an electronic device on a semiconductor wafer involves a complex process of depositing and removing many layers. Typically, patterning of layer material involves the application of an organic photoresist onto a semiconductor wafer. After the chemical action of the plasma etches the target material, the semiconductor wafer needs to be cleaned to remove the organic photoresist. If the organic photoresist is not removed, the organic photoresist will contaminate the semiconductor wafer and damage the electronic device on the semiconductor wafer. In addition, after a chemical mechanical polishing (CMP) operation, residual particles or films remain on the surface of the semiconductor wafer. Similarly, these residual particles or films may cause defects such as scratches on the surface of the wafer, which may render the device on the wafer inoperable. To avoid damaging the device, the wafer also needs to be cleaned after the CMP process. As such, the cleaning operation is a very important step that is repeated many times throughout the process of manufacturing a semiconductor device.

1 is a simplified side view of a conventional system used for cleaning semiconductor wafers. The cleaning system includes two brushes 110 that are configured to receive the semiconductor wafer 112 between the brushes. Foam 114 is supplied to the surface of the semiconductor wafer 112, and the brush 110 rotates to scrub the surface of the semiconductor wafer to remove particles and films. The problem with applying the foam 114 in an open environment is that the foam grows randomly around the brush 110 and cannot be sent to a particular surface area of the semiconductor wafer 112. That is, when applied in an open environment, the flow of foam 114 becomes difficult to control. In addition, different properties of the foam 114 result in different cleaning capabilities, and the properties of the foam 114 are also difficult to control when applied in an open environment. In addition, applying the foam 114 in an open environment is very wasteful because a large amount of foam is required to ensure uniform distribution across the surface of the semiconductor wafer 112.

In view of the foregoing, when applied on the surface of a semiconductor wafer, there is a need to save foam and to control the physical properties and flow of the foam.

Summary of the Invention

Broadly speaking, the present invention meets this need by providing an apparatus and method for cleaning a substrate. The invention can be implemented in a number of ways, including as a process, apparatus, system, computer readable medium, or device. Some inventive embodiments of the present invention are described below.

According to a first aspect of the invention, an apparatus for use in processing a substrate is provided. The device includes a brush enclosure extending over its length. The brush enclosure is configured to be disposed above the surface of the substrate and has an open area configured to be disposed proximate to the substrate. The open area extends over the length of the brush enclosure and allows the foam from inside the brush enclosure to contact the surface of the substrate.

According to a second aspect of the invention, a brush enclosure is provided for use in processing a substrate. The brush enclosure includes an elongated enclosure configured to enclose the brush. The elongated enclosure is configured to be disposed above the surface of the substrate and has opposite ends defining the length. The elongated enclosure also has an open area along the length of the elongated enclosure. The open area is configured to be disposed above the surface of the substrate, and enables the surface of the brush to contact the surface of the substrate.

According to a third aspect of the invention, a substrate cleaning system is provided. The system includes a first brush enclosure and a first brush partially enclosed within the first brush enclosure. The partially enclosed first brush is configured to be disposed above the surface of the substrate. The system also includes a first drive roller and a second drive roller, wherein the first and second drive rollers are configured to receive an edge of the substrate so that when the substrate is positioned under a partially enclosed first brush, the substrate Support and rotate.

According to a fourth aspect of the present invention, a method of cleaning a substrate is provided. In this method, foam is provided on the surface of the substrate. The surface of the substrate is then scrubbed with a brush. Pressure is applied to the foam, and the compressed foam is channeled to produce a jammed foam. Brush scrubbing of the substrate surface and channeling across the substrate surface of the compressed foam promotes removal of particles from the surface of the substrate.

Other aspects and advantages of the present invention will become apparent from the following detailed description, which, in conjunction with the accompanying drawings, illustrates the principles of the invention in an exemplary manner.

Brief description of the drawings

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be readily understood by the following detailed description taken in conjunction with the accompanying drawings in which like reference characters designate like elements.

1 is a simplified side view of a conventional system used to clean a semiconductor wafer.

2A is a perspective view of a brush partially enclosed within a brush enclosure, according to one embodiment of the invention.

FIG. 2B is a side view of the brush enclosure and brush shown in FIG. 2A, in accordance with an embodiment of the present invention. FIG.

3 is a perspective view of a substrate cleaning system, in accordance with an embodiment of the present invention.

4 is a side view of a brush partially enclosed in a foam, in accordance with an embodiment of the present invention.

FIG. 5A is an enlarged side view of the gap region shown in FIG. 4, in accordance with an embodiment of the present invention. FIG.

FIG. 5B is another embodiment of the gap region shown in FIG. 5A.

6 is a flowchart diagram of a method of cleaning a substrate, in accordance with an embodiment of the present invention.

details

Disclosed is an apparatus and method for cleaning a substrate. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without some or all of these specific details. In other respects, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention.

Embodiments described herein provide a brush enclosure for enclosing brushes and foams. In particular, the brush enclosure is configured to contain and control the flow and physical properties of the foam. As will be described in more detail below, the shape of the brush enclosure creates different cleaning effects within the brush enclosure.

2A is a perspective view of a brush 210 partially enclosed within a brush enclosure 212, in accordance with an embodiment of the present invention. For illustrative purposes, brush enclosure 212 includes a cut surface of reference region 220 that indicates that brush 210 is partially enclosed within the brush enclosure. Brush 210 rotates to remove particles to sweep the particles off the surface of the substrate. Brush enclosure 212 may be configured to enclose any suitable brush 210 used to process the substrate. For example, as shown in FIG. 2A, the exemplary brush 210 includes a series of parallel and continuously protruding strips perpendicular to the curved brush surface. Another exemplary suitable brush 210 has a rugged shape that includes a set of cylinders protruding perpendicular to the curved brush surface.

Brush enclosure 212 is an elongated member that extends over length 218. As shown in FIG. 2A, the length 218 of the brush enclosure 212 extends the length of the brush 210. However, in other embodiments, the length 218 of the brush enclosure 212 may be shorter or longer than the length of the brush 210. 2A illustrates a brush enclosure 212 having a tube form, in accordance with an embodiment of the present invention. However, brush enclosure 212 need not necessarily have a “tube” shape, and if the brush enclosure may be configured in such a way that it can partially enclose brush 210, for example, a right cross section, an elliptical cross section. It may be of any suitable configuration, shape and / or size, such as elongated members such as triangular cross sections, circular cross sections and the like.

As will be described in more detail below, brush enclosure 212 also includes an open region 222, and in one embodiment, two opposing flanges 214 extending along the length and sides of the open region 222. ) Additionally. Brush enclosure 212 is made of a chemically inert material. Examples of chemically inert materials include plastics, Delrin, polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET) and the like.

FIG. 2B is a side view of the brush 210 and brush enclosure 212 shown in FIG. 2A, in accordance with an embodiment of the present invention. Here, a brush 210 partially enclosed within the brush enclosure 212 is disposed above the substrate 216. As shown in FIG. 2B, the brush enclosure 212 includes an open area 222 and two opposing flanges 214. The open area 222 is configured to be disposed proximate to the surface of the substrate 216 and allows the surface of the brush 210 to contact the surface of the substrate. In one embodiment, the open area 222 extends along the entire length of the brush enclosure 212. In other embodiments, the length of open area 222 is less than the length of brush enclosure 212.

The flange 214 also extends in the outward radial direction from the outer surface of the brush enclosure 212. Each flange 214 extends along the length and side of the open area 222. In one embodiment, each flange 214 extends along the entire length of the open area 222. In other embodiments, the length of each flange 214 is smaller than the length of the open area 222. Each flange 214 defines a surface generally parallel to the surface of the substrate 216. As used herein, the expression “substantially” means that the angle between each flange 214 and the surface of the substrate 216 is between about 0 degrees and about ± 45 degrees. As shown in FIG. 2B, the brush enclosure 212 includes two flanges 214 on opposite ends. However, in other embodiments, the brush enclosure 212 may have one flange 214 instead of two flanges.

3 is a perspective view of a substrate cleaning system, in accordance with an embodiment of the present invention. As shown in FIG. 3, the substrate cleaning system includes two brushes 210, two drive rollers 310, and a substrate 216 partially enclosed in the brush enclosure 212. Drive roller 310 receives the edge of substrate 216 to support and rotate the substrate. The partially enclosed brushes 210 are directed relative to one another such that the substrate 216 is received between the brushes. 3 shows the use of two partially enclosed brushes 210 to clean the substrate 216. However, in another embodiment, one partially enclosed brush 210 may be used to clean the substrate 216. Further, in another embodiment, the substrate cleaning system includes two brushes 210, but one brush is partially enclosed in the brush enclosure 212, and the second brush is not enclosed within the brush enclosure.

As will be described in more detail below, the substrate cleaning system uses foam to clean the substrate 216. Many bubbles combine to form a form. Bubbles are two-phase systems in which gas is enclosed by a liquid. This liquid forms a film or film that traps the gas. In the foam, the liquid also exists in the spaces between the bubbles. In one embodiment, each brush 210 consists of a high-porosity foam, such as polyvinyl alcohol (PVA), and can be used as a foam generator and foam applicator. In order to create a foam in the brush enclosure 212, gas and liquid are supplied to the brush 210 through the conduit 312 under pressure. The gas and liquid are mixed in porous PVA brush 210 to create a foam. In another embodiment, the pre-generated foam is supplied to the brush 210 via the conduit 312. To spread the foam over the entire surface of the substrate 216, the drive roller 310 rotates the substrate 216. Alternatively, the brush 210 can move across the surface of the substrate 216 to spread the foam. The foam may be further spread by the combination of the rotating substrate 216 and the brush 210 moving across the surface of the substrate.

4 is a side view of a brush 210 partially enclosed with foam 410, in accordance with an embodiment of the present invention. As shown in FIG. 4, a brush 210 is disposed over the substrate 216, and the brush enclosure 212 partially encloses the brush and foam 410. The enclosure of the brush 210 and the foam 410 forms different regions 412, 414, and 416 that clean the surface of the substrate 216. Within the region defined as region A 412, the surface of the brush 210 contacts the surface of the substrate 216. As the brush 210 rotates, the brush physically scrubs the surface of the substrate 216 to remove particles. As a result, in region A 412, the surface of the substrate 216 is cleaned by scrubbing.

On the other hand, within the region defined as region B 412, the surface of the substrate 216 is cleaned with the foam 410 primarily by chemical treatment. The open area 222 of the brush enclosure 212 allows the foam 410 from inside the brush enclosure to contact the surface of the substrate 216. As mentioned above, the foam 410 consists of liquid and gas bubbles. When the bubbles in the foam 410 burst at the surface of the substrate 216, gas is released and the gas and liquid are placed in direct contact with the surface of the substrate 216. Chemical reactions occur between the gas, the liquid, and the surface of the substrate 216 to facilitate removal of layers of particles and materials (eg, organic material layers) from the surface of the substrate.

In order to chemically treat the surface of the substrate 216 with the foam 410, the gas is preferably a gas or any combination of gases that chemically reacts or promotes a chemical reaction when placed in direct contact with another material. Examples of gases that react with contaminants include ozone (O ₃ ), oxygen (O ₂ ), hydrochloric acid (HCl) and hydrofluoric acid (HF), and inert gases such as nitrogen (N ₂ ) and argon (Ar). Included. Gases include ozone (O ₃ ) and nitrogen (N ₂ ); Ozone (O ₃ ) and argon (Ar); Ozone (O ₃ ), oxygen (O ₂ ), and nitrogen (N ₂ ); Ozone (O ₃ ), oxygen (O ₂ ) and argon (Ar); Ozone (O ₃ ), oxygen (O ₂ ), nitrogen (N ₂ ) and argon (Ar); Oxygen (O ₂ ) and argon (Ar); Oxygen (O ₂ ) and nitrogen (N ₂ ); And any combination of gases such as oxygen (O ₂ ), argon (Ar) and nitrogen (N ₂ ). In one embodiment of the present invention, ozone is used as the gas because ozone chemically reacts with the organic material on the surface of the substrate 216 when combined with water. The organic material may be an organic photoresist material, which is commonly used in semiconductor photolithography processes. Nitrogen can be combined with ozone to increase the density of ozone in the bubble.

The liquid used to produce the foam 410 is any liquid or combination of liquids that chemically reacts or promotes a chemical reaction when placed in direct contact with another material. The liquid may be a semi-aqueous or aqueous solution of deionized water (DIW) containing a suitable cleaning fluid. Examples of liquids include water (H ₂ O); Deionized water (DIW); Water (H ₂ O) and a cleaning fluid; Water (H ₂ O) and surfactants; Water (H ₂ O) and cleaning fluids, and surfactants; Deionized water (DIW) and surfactants; And deionized water (DIW), cleaning fluids and surfactants, and the like. As mentioned above, one embodiment of the present invention uses water as the liquid, since water enables or promotes a chemical reaction between ozone and the organic photoresist material.

Within the region defined by region C 416, the surface of the substrate 216 is mainly cleaned by the attraction of particles to the gas / liquid interface of the bubbles. As shown in FIG. 4, the space between the surface of each flange 214 and the surface of the substrate 216 defines a gap 224. The gap 224 is maintained to form a non-Newtonian flow field. In one embodiment, the dimensions of the gap 224 range from about 0.1 mm to about 5 mm. As used herein, the expression “about” means that certain dimensions or parameters may vary within acceptable manufacturing errors for a given application. In one embodiment, the acceptable manufacturing tolerance is ± 10%.

Pressure is applied to the foam 410 inside the brush enclosure 212, and the foam is channeled into the gap 224 (ie, region C 416) to produce a jammed foam. The jammed foam is produced by the application of a force that compresses the foam 410. When compressed inside the gap 224, the bubbles inside the foam 410 are deformed and rearranged into a more dense configuration. In fact, the pressure and the shape of the gap 224 cause the foam 410 to change from a metastable position to a more stable position within the region C 416.

As pressure channels the foam 410 through the gap 224 in the brush enclosure 212, a shear force is created between the bubbles of the jammed foam. Shear forces cause the bubbles to move locally and locally. The local movement of the bubbles caused by the shear force releases an explosion of energy, which is transferred to the surface of the substrate 216 to facilitate the removal of particles from the surface of the substrate. Specifically, the bubbles inside the jammed foam want to be in a minimum energy state and the angle between the bubbles is approximately 120 degrees. Shear force causes bubbles of minimum energy state to pass through other bubbles, the angle between the bubbles changes, and the change in angle results in a higher energy state. In fact, the change in angles between the bubbles is equated with the change in energy. Thus, energy is released not by the bursting of the bubbles, but by the local rearrangement inside the jammed foam.

As shown in FIG. 4, in accordance with one embodiment of the present invention, the brush enclosure 212 may further include a removal conduit 450 located within the flange 214. Removal conduit 450 is configured to remove foam 410, liquid, particles, and the like from the surface of substrate 216 by applying a vacuum. Also, in other embodiments, conduit 450 may be configured to provide deionized water (DIW) and / or chemical rinse to promote foam removal. In another embodiment, as a means of removing liquid from the surface of the substrate 216, in order to reduce the surface tension of the liquid on the surface of the water, the additional conduit 450 may be further added, such as isopropyl alcohol (IPA). It is also possible to supply chemicals and / or gases.

5A and 5B are enlarged side views of the gap shown in FIG. 4, in accordance with an embodiment of the present invention. 5A and 5B, the gap region shows a brush 210 disposed over the substrate 216 partially enclosed within the brush enclosure 212. Brush enclosure 212 includes flange 214, and the space between the surface of the flange and the surface of substrate 216 defines a gap 224. Different gap 224 shapes may be used to address the mechanical properties and dimensions of the foam 410 and bubbles inside the foam. The combination of the mechanical and chemical properties of the foam 410 provides flexibility of the cleaning process by changing the original properties of the foam for different cleaning conditions. As an example, as shown in FIG. 5A, small gap 224 forms small bubbles inside the gap. Because the gap 224 is small, the pressure inside the brush enclosure 212 is large, and as a result, the foam 410 exits the gap 224 at a high speed. The combination of smaller bubble size and high foam viscosity increases the shear force between the bubbles. Higher shear forces result in greater energy being transferred to the surface of the substrate 216 when the bubbles in the jammed foam are rearranged locally.

On the other hand, as shown in FIG. 5B, the larger gap 224 forms larger bubbles in the gap. Because the gap 224 is large, the pressure inside the brush enclosure 212 is smaller, and as a result, the foam 410 exits the gap at a lower speed. The combination of larger bubble size and lower viscosity promotes the removal of particles from vias and trenches. Because different gap shapes form different cleaning properties, in accordance with one embodiment of the present invention, two flanges on opposite sides of brush enclosure 212 may be configured in different shapes. For example, one flange 214 has a small gap to form a higher shear force, while opposite flanges 214 on the same brush enclosure 212 have a larger gap to remove particles from vias and trenches. It may be configured to have. Thus, in this embodiment, the broth enclosure 212 may be configured to satisfy two different cleaning conditions.

6 is a flowchart diagram of a method for cleaning a substrate, in accordance with an embodiment of the present invention. Beginning at step 610, a foam is provided on the surface of the substrate. In the region where the surface of the brush contacts the surface of the substrate, the surface of the substrate is physically scrubbed by the brush in step 612. At the same time, within the area formed by the brush enclosure, between the area where the brush is in contact with the surface of the substrate and the area defined by the gap, the surface of the substrate is cleaned primarily by chemical treatment with foam in step 613. As mentioned above, chemical treatment facilitates the removal of particles and films from the surface of the substrate by placing gas and liquid in direct contact with the surface of the substrate, through the bursting of bubbles inside the foam. At the same time, in step 614, pressure is applied to the foam, and as a result, in step 616, the compressed foam is channeled to produce a jammed foam. In particular, the foam is channeled into a gap formed by the brush enclosure. The gap is defined by the space between the brush enclosure (eg flange) and the surface of the substrate. The pressure applied to the foam and the shape of the gap compresses the foam to create a jammed foam. Local relocation of bubbles inside the jammed foam releases energy, which promotes the removal of particles and film from the surface of the substrate.

In short, the present invention described above provides an apparatus and method for use in cleaning a substrate. The enclosure of the foam reduces the amount of foam needed to cover a particular surface area of the substrate. In addition, the shape of the brush enclosure can specifically govern the flow of the foam and can control the physical properties of the foam, further facilitating the removal of particles and film from the surface of the substrate. As a result, the brush enclosure allows different cleaning operations (eg, scrubbing, chemical treatment, and rearrangement of bubbles inside the jammed foam) to be performed simultaneously on the surface area of the substrate.

While the invention has been described in some detail for clarity of understanding, it will be apparent that certain changes or modifications may be made within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope of the appended claims and equivalents.

Claims (20)

A brush enclosure extending over its length, The brush enclosure is configured to be disposed on a surface of the substrate, the brush enclosure having an open area configured to be disposed proximate to the substrate, the open area being formed from the foam from inside the brush enclosure if the substrate is present. foam), wherein the open area extends over the length of the brush enclosure. The method of claim 1, And the brush enclosure has a tube shape. The method of claim 1, Wherein the length of the brush enclosure is configured to extend the length of the brush. An elongated enclosure configured to enclose the brush, The elongated enclosure is configured to be disposed on a surface of the substrate, the elongated enclosure having an open area along the length of the elongated enclosure with opposite ends defining a length, and configured to be disposed on a surface of the substrate. Wherein said open area is such that the surface of said brush, if present, makes contact with the surface of said substrate, if present. The method of claim 4, wherein A flange extending in an outward radial direction from an outer surface of the elongated enclosure, along a longitudinal direction of the elongated enclosure, And the flange defines a surface generally parallel to the surface of the substrate when the substrate is present. The method of claim 5, The space between the surface of the substrate and the surface of the flange, where the substrate is present, defines a gap, wherein the gap enables the creation of jammed foam. The method of claim 6, And the gap has a dimension of about 0.1 mm to about 5 mm. The method of claim 5, And the flange has a conduit configured to remove liquid resulting from the collapse of the jammed foam from the surface of the substrate when the substrate is present. The method of claim 4, wherein The length of the brush enclosure is configured to extend the length of the brush, the brush enclosure for substrate processing. The method of claim 4, wherein And the open area extends over the length of the elongated enclosure. A first brush enclosure; A first brush configured to be disposed on a surface of the substrate and partially enclosed in the first brush enclosure; A first drive roller; And A second drive roller, Wherein the first and second drive rollers are configured to receive an edge of the substrate to support and rotate the substrate when the substrate is positioned below the partially enclosed first brush. The method of claim 11, Second brush enclosure; Further comprising a second brush partially enclosed within the second brush enclosure, And the partially enclosed second brush is directed against the partially enclosed first brush to receive a substrate between the partially enclosed first and second brushes. Providing a foam to the surface of the substrate; Brush scrubbing the surface of the substrate; Providing pressure to the foam; And Channeling the compressed foam to produce a jammed foam, Brush scrubbing the surface of the substrate and channeling the compressed foam over the surface of the substrate facilitates removal of particles from the surface of the substrate. The method of claim 13, Chemically treating the surface of the substrate with the foam; And the chemical treatment promotes removal of particles from the surface of the substrate. The method of claim 14, Chemically treating the surface of the substrate with a foam, Rupturing bubbles inside the foam to release gas and liquid onto the surface of the substrate, And the gas and liquid promote removal of particles from the surface of the substrate. The method of claim 15, Wherein the gas is defined by one or more of ozone (O ₃ ), oxygen (O ₂ ), hydrochloric acid (HCl), hydrofluoric acid (HF), nitrogen (N ₂ ), and argon (Ar). The method of claim 15, Wherein the liquid is defined by one or more of water (H ₂ O), deionized water (DIW), cleaning fluid and surfactant. The method of claim 13, And the pressure applied to the jammed foam creates a shear force on the jammed foam. The method of claim 13, Providing pressure to the foam, Applying gas and liquid through the brush, The application of the gas and liquid enables the creation of pressure on the foam. The method of claim 13, Channeling the compressed foam to produce a jammed foam, Channeling the compressed foam into a gap; Wherein the gap is defined by the space between the surface of the brush enclosure and the surface of the substrate.

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