Cleaning member and substrate cleaning apparatus

A cleaning member 10, for use in cleaning a substrate W, comprises: a tip surface 13 configured to be in contact with the substrate W when cleaning the substrate W, and the tip surface 13 being not covered with a skin layer 11; and a circumferential part having a covered part 16, which is disposed on the base end side and a circumferential surface of which is covered with the skin layer 11, and an exposed part 17, which is disposed on the tip end side and a circumferential surface of which is not covered with the skin layer 11.

TECHNICAL FIELD

The present invention relates to a cleaning member and a substrate cleaning apparatus, which are used to clean a substrate such as a semiconductor wafer.

This application claims a priority of Japanese Patent Application No. 2016-079462 filed on Apr. 12, 2016 and incorporates all the contents of the application by reference.

BACKGROUND ART

Conventionally, a cleaning member with a skin layer for use in cleaning by chemical mechanical polishing (hereinafter referred to as CMP) process is known. Such a cleaning member is manufactured by molding the member, cutting the surface to be in contact with a substrate, and forming a skin layer on the surface that has been in contact with the inner surface of the mold (i.e., the side surface of the cleaning member). The skin layer has continuous pores having smaller diameters than those in the inner part made of sponge and also has a lower porosity than the inner sponge part. Therefore, using the cleaning member with such a skin layer for cleaning can hold sufficient water inside while preventing the liquid inside from leaking out of the surface, which enables the cleaning member to have desired water absorbing properties and water supplying properties during cleaning process. In addition, this cleaning member advantageously does not produce particles substantially and has a long life in general. For example, Japanese Patent Laid Open No. 2011-56382 discloses a sponge member having a shaft and a skin layer.

If a cleaning member with a skin layer on the side surface is used for cleaning by CMP, the skin layer on the side surface may be situated between the cleaning member and a substrate during cleaning process and cause contact contamination on the substrate (in such case, there might be resulting in cleaning irregularities in the circumferential direction. SeeFIG. 12).

On the other hand, if a cleaning member without a skin layer on the side surface is used, cleaning liquid collide with the bare side surface and go into the cleaning member. As a result, particles in the cleaning liquid may go into the cleaning member and then go down to a substrate to adhere to it. In addition, the cleaning member without a skin layer may not have strength enough to keep the cleaning properties under specific circumstances. Therefore, to avoid an occurrence of contact contamination using the cleaning member without a skin layer for cleaning a substrate seems to be preferable, but from other point of view, the cleaning member without a skin layer seems to be not preferable.

SUMMARY OF THE INVENTION

Problem to be Solved by Invention

As the technology for manufacturing fine semiconductor devices has developed recently, the requirements for substrate processing apparatuses such as cleaning apparatuses are becoming stricter in terms of the cleaning level. And now the measures for preventing the stains due to a cleaning member itself are required.

The present invention has been made to solve the problem. An object of the present invention is to provide a cleaning member and a substrate cleaning apparatus that prevent particles in cleaning liquid from coming inside and prevent the stains due to a skin layer.

Solution to Problem

A cleaning member according to the present invention is exemplified as a cleaning member for use in cleaning a substrate, may comprise:

a tip surface configured to be in contact with the substrate when cleaning the substrate, and the tip surface being not covered with a skin layer; and

a circumferential part having a covered part, which is disposed on the base end side and a circumferential surface of which is covered with the skin layer, and an exposed part, which is disposed on the tip end side and a circumferential surface of which is not covered with the skin layer.

In the cleaning member according to concept 1,

the exposed part may have a height equal to or more than a length of compression, by which the cleaning member can be compressed at the time of compression.

In the cleaning member according to concept 1,

the exposed part may have a height in the range of 1 mm to 5 mm.

In the cleaning member according to any one of concepts 1 to 3,

a base surface may not be covered with the skin layer.

In the cleaning member according to any one of concepts 1 to 4,

wherein the cleaning member may be a pencil-type cleaning member.

In the cleaning member according to any one of concepts 1 to 4,

wherein the cleaning member may be a nodule.

In the cleaning member according to any one of concepts 1 to 6,

wherein a tip part of the cleaning member may have a smaller cross section in the part near a tip than in the part near a base.

A substrate cleaning apparatus may comprise:

a substrate holder for holding a substrate; and

the cleaning member, according to any one of concepts 1 to 7, used to clean the substrate.

Effects of Invention

According to the present invention, the cleaning member has the tip surface without the skin layer; and the circumferential part having the covered part with the skin layer on the circumferential surface, which is disposed on the base end side, and the exposed part without the skin layer on the circumferential surface, which is disposed on the tip end side. Thus, the cleaning member can prevent particles in cleaning liquid from coming inside as much as possible; and can prevent the contact of the skin layer with the substrate and prevent the contact contamination due to the contact of the skin layer with the substrate as much as possible.

DESCRIPTION OF EMBODIMENTS

Embodiments

An embodiment of a substrate processing apparatus having a substrate cleaning apparatus of the present invention will now be described with reference to the accompanying drawings.FIGS. 1 to 11illustrate embodiments of the present invention.

As shown inFIG. 1, a substrate processing apparatus has a nearly rectangular housing110, and a load port112, on which a substrate cassette for storing many substrates W is disposed. The load port112is disposed adjacent to the housing110. The load port112can have an open cassette, a standard mechanical interface (hereinafter referred to as SMIF) pod, or a front opening unified pod (hereinafter referred to as FOUP). The SMIF pod and the FOUP is a closed container that has a substrate cassette inside and a partition wall as a cover for separating its internal environment from the outside space. The substrates W are semiconductor wafers, for example.

The housing110holds a plurality of polishing units114ato114d(four units inFIG. 1), a first substrate cleaning apparatus50and a second substrate cleaning apparatus55for cleaning a substrate W after polishing, and a drying unit60for drying the substrate W after cleaning. The polishing units114ato114dare arranged in the longitudinal direction of the substrate processing apparatus. The substrate cleaning apparatuses50and55and the drying unit60are also arranged in the longitudinal direction of the substrate processing apparatus.

A first transferring robot122is disposed in the area surrounded by the load port112, the polishing unit114anear the load port112, and the drying unit60. A transferring unit65is disposed along the polishing units114ato114d, and the substrate cleaning apparatuses50and55and the drying unit60. The first transferring robot122receives a substrate W from the load port112and delivers the substrate W to the transferring unit65before polishing, or receives a substrate W from the transferring unit65after drying at the drying unit60.

A second transferring robot66is disposed between the first substrate cleaning apparatus50and the second substrate cleaning apparatus55for transferring a substrate W between the first substrate cleaning apparatus50and the second substrate cleaning apparatus55. A third transferring robot67is disposed between the second substrate cleaning apparatus55and the drying unit60for transferring a substrate W between the second substrate cleaning apparatus55and the drying unit60. The housing110contains a control unit150for controlling the movements of the individual parts of the substrate processing apparatus, and a memory unit155for storing various kinds of data. In this embodiment, the housing110contains the control unit150and the memory unit155, however, this is not always the case. Alternatively, the control unit150and/or the memory unit155may be disposed outside the housing110. In this embodiment, even if the control unit150and the memory unit155are disposed outside the substrate cleaning apparatuses50and55, the control unit150and the memory unit155are used to carry out the functions of the substrate cleaning apparatuses50and55. Therefore, the control unit150and the memory unit155are regarded as parts of the substrate cleaning apparatuses50and55.

In the following description, the first substrate cleaning apparatus50is a roller-type cleaning apparatus and the second substrate cleaning apparatus55is a pencil-type cleaning apparatus, however, this is not always the case.

Alternatively, the first substrate cleaning apparatus50may be a pencil-type cleaning apparatus like the second substrate cleaning apparatus55, or a two-fluid jet cleaning apparatus that cleans the surface of a substrate W with a two-fluid jet. The second substrate cleaning apparatus55may be a roller-type cleaning apparatus like the first substrate cleaning apparatus50, or a two-fluid jet cleaning apparatus that cleans the surface of a substrate W with a two-fluid jet.

In the roller-type cleaning apparatus (the first substrate cleaning apparatus50) ofFIG. 2, linear roller-type cleaning members52and53, which extend substantially across the diameter of a substrate W, revolve around their axes disposed parallel to the substrate W while being in contact with the substrate W to scrub the surface of the substrate W in the presence of cleaning liquid. In the pencil-type cleaning apparatus (the second substrate cleaning apparatus55) ofFIG. 3, a vertically extending cylindrical pencil-type cleaning member10bspins around its axis and moves in one direction while its lower end surface is in contact with a substrate W to scrub the surface of the substrate W in the presence of cleaning liquid.

The drying unit60may be a spin-drying unit that ejects IPA steam from moving nozzles to a substrate W to blow dry the substrate W while spinning the substrate W horizontally at a high speed to dry the substrate W by centrifugal force.

As shown inFIG. 2, the first substrate cleaning apparatus50has a plurality of horizontally movable spindles51(four spindles inFIG. 2) as a mechanism for spinning a substrate W that spins a substrate W horizontally while supporting the substrate W faceup in contact with the rim of the substrate W, a first roller-type cleaning member (a sponge roller)52revolvably supported by a roller holder (not shown), and a second roller-type cleaning member (a sponge roller)53revolvably supported by a roller holder (not shown). The first roller-type cleaning member52and the second roller-type cleaning member53are long cylindrical members made of PVA, for example. The first roller-type cleaning member52may be moved up and down by its roller holder with respect to the front surface of the substrate W, and the second roller-type cleaning member53may be moved up and down by its roller holder with respect to the rear surface of the substrate W.

The first roller-type cleaning member52may be revolved by a driving mechanism (not shown), and the second roller-type cleaning member53may be revolved by a driving mechanism (not shown). Two nozzles21aand21bare disposed above the substrate W, which is supported and spun by the spindles51, for supplying cleaning liquid to the surface of the substrate W. The nozzle21amay supply rinsing liquid (such as deionized water) to the surface of the substrate W, and the nozzle21bmay supply chemical solution to the surface of the substrate W, for example.

In the first substrate cleaning apparatus50, spindles51have pieces51awith a groove in its outer side surface on the upper part of the spindles. The spindles51support the substrate W with the rim of the substrate W in the grooves in the pieces51awhile applying inward pressure to the rim of the substrate W. When the pieces51aspin around their axes in this state, the substrate W is spun horizontally. In this example, among the four pieces51a, two pieces51aapply rotary force to the substrate W and the other two pieces51afunction as bearings for receiving the rotary force from the substrate W. Alternatively, all the four pieces51amay be connected to a driving mechanism to apply rotary force to the substrate W.

The first roller-type cleaning member52and/or the second roller-type cleaning member53may have a plurality of nodules10aon the surface(s). These nodules may be arranged at regular intervals. In the aspect ofFIG. 2, the first roller-type cleaning member52has the nodules10a, however, this is not always the case. The inside of the first roller-type cleaning member52and/or the second roller-type cleaning member53may be supplied with cleaning liquid, which is then supplied to the substrate W from the ends of the nodules. More specifically, cleaning liquid may be supplied into the cylindrical body/bodies of the first roller-type cleaning member52and/or the second roller-type cleaning member53and then supplied to the substrate W from the ends of the nodules while the nodules are cleaning the substrate W.

As shown inFIG. 3, the second substrate cleaning apparatus55has a plurality of spindles51(four spindles inFIG. 3) similar to the spindles51of the first substrate cleaning apparatus50as a mechanism for spinning a substrate, a vertically extending pole56that can be moved up and down, a horizontally extending arm57with one end rotatably attached to the tip end of the pole56, and a cylindrical pencil-type cleaning member10bspinnably and downwardly attached to the other end of the arm57. Two nozzles21aand21bare disposed above the substrate W, which is supported and spun by the spindles51, for supplying cleaning liquid to the surface of the substrate W, as in the first substrate cleaning apparatus50. The nozzle21amay supply rinsing liquid (such as deionized water) to the surface of the substrate W, and the nozzle21bmay supply chemical solution to the surface of the substrate W, for example.

The pencil-type cleaning member10bis held by a cleaning member holder1to be spinnably and downwardly attached to an end of the arm57, and spun by a driving mechanism (not shown) around its axis. This rotation axis is orthogonal to the substrate W. The pencil-type cleaning member10bis made of PVA, for example. When the arm57moves around the pole56, the pencil-type cleaning member10bat the end of the arm57moves along an arc on the substrate W. The end of the arm57may extend to the center O of the substrate W. In this aspect, the orbit of the pencil-type cleaning member10bis on the center O of the substrate W. The pencil-type cleaning member10bmay be moved beyond the circumference of the substrate W. The orbit of the pencil-type cleaning member10b, determined by the movement of the arm57, can be an arc of a circle with a radius equal to the length of the arm57. The pencil-type cleaning member10bmay move between the circumference and the position beyond the center O of the substrate W.

The arm57has the cleaning member holder1at the tip end. As shown inFIG. 4, the cleaning member holder1may have a holder core3, a sleeve4, and a ring5.

The holder core3may have a holder core body3bhaving a larger outer diameter at the base, and a plurality of projections3aon the lower end surface of the holder core body3b. The holder core body3bmay have a through-hole3cfor accepting a fastener6such as a screw.

The sleeve4may have a plurality of chucks4a. The sleeve4may have a hole7formed by the inner surfaces of the chucks4afor accepting the base part of the cleaning member10. The sleeve4may have a screw hole4cfor accepting the fastener such as a screw6in the base end surface. The sleeve may have a protrusion4daround the tip outer surface. The protrusion4dmay have a projection4earound the base outer surface.

The ring5may have a cylindrical body having an inner diameter substantially equal to the outer diameter of the sleeve4. The ring5may have a groove5afor accepting the projection4eof the sleeve4in its inner surface.

The pencil-type cleaning member10bmay have a nearly cylindrical base part10b1, and a nearly cylindrical tip part10b2having a larger diameter than the base part10b1.

The holder core3may be inserted into the central hole of the sleeve4until the undersurface of a flange3bcomes into contact with the upper end surface of the sleeve4. The holder core3may be fastened to the sleeve4with the fastener such as a screw6in this position.

The base part of the pencil-type cleaning member10bmay be inserted into the hole7formed by the inner surfaces of the four chucks4a, and then the sleeve4may be inserted into the ring5. As a result, the chucks4aspread outward are pressed inward and the projections4bon the inner surfaces of the chucks4abite into the outer surface of the cleaning member10to firmly lock the cleaning member10. In addition, the projections3aon the lower end surface of the holder core3also bite into the upper end surface of the cleaning member10to firmly lock the cleaning member10. The projections4eon the outer surfaces of the chucks4amay be engaged with the groove5ain the inner surface of the ring5to firmly attach the sleeve4to the ring5.

As shown inFIGS. 2 and 3, in this embodiment, the spindles51support the substrate W as substrate supporting components, however, this is not always the case. Alternatively, the substrate W may be held by chucks as substrate supporting components. In this embodiment, “to support” includes the meaning of “to hold.” When the chucks support (hold) the substrate W, the substrate W may be spun by a separate spinning component. When the spindles51are used, the substrate W is spun by the spindles51while being supported by the spindles51. The spindles51thus have two functions of supporting the substrate W and spinning the substrate W. InFIGS. 2 and 3, the substrate W is supported horizontally, however, this is not always the case. Alternatively, the substrate W may be supported vertically, for example.

In this embodiment, the nozzles21are provided as supplying components20for supplying cleaning liquid to the substrate W, which is supported by the substrate supporting components, however, this is not always the case.

In this embodiment, examples of the cleaning liquid include rinsing liquid such as deionized water (DIW), and chemical solutions such as a mixture of ammonium hydroxide and hydrogen peroxide (SC1), a mixture of hydrochloric acid and hydrogen peroxide (SC2), a mixture of sulfuric acid and hydrogen peroxide (SPM), a sulfuric acid-hydrogen peroxide mixture, and hydrofluoric acid. In this embodiment, the cleaning liquid means either of rinsing liquid or chemical solution, otherwise described.

The cleaning member10for use in the substrate cleaning apparatuses will now be described. More specifically, the cleaning member10for the pencil-type cleaning member10bor each nodule10aof the roller-type cleaning member will now be described. The “substrate cleaning apparatus” means either of the first substrate cleaning apparatus50or the second substrate cleaning apparatus55, or both of the first substrate cleaning apparatus50and the second substrate cleaning apparatus55, otherwise described.

As shown inFIGS. 5 to 7, the cleaning member10of this embodiment has a tip surface13configured to be in contact with a substrate W when cleaning the substrate W, and a circumferential part having a covered part16disposed on the base end side and an exposed part17disposed on the tip end side. In the tip surface13, the sponge part12is not covered with the skin layer11. In the covered part16, the circumferential surface of the sponge part12is covered with the skin layer11. In the exposed part17, the circumferential surface of the sponge part12is not covered with the skin layer11. The cleaning member10of this embodiment is a collective term for the nodules10aor the pencil-type cleaning member10band means either of the nodules10aor the pencil-type cleaning member10b, otherwise described.

The exposed part17may have a height equal to or more than the length of compression by which the cleaning member10can be compressed at the time of compression. The length of compression is determined by a force applied to the cleaning member10for compression and a material of the cleaning member10. The “length of compression” may be measured in a pretest, or may be calculated by simulation. The “length of compression” may be determined based on the length of contraction in the specification. In this case, the “length of compression” should be equal to or more than the length of contraction in the specification. The “length of contraction” in the specification means the length by which the cleaning member10can be contracted when applying a predetermined force (2N, for example) to the cleaning member10without spinning the substrate W and the cleaning member10.

The “length of compression” can be changed between the case in which the nodule10ais used as the cleaning member10and the case in which the pencil-type cleaning member10bis used as the cleaning member10. The length of compression for the nodule10acan be shorter the length of compression for the pencil-type cleaning member10b.

The exposed part17may have a height in the range of 1 mm to 5 mm, for example. When the cleaning member10is used for the pencil-type cleaning member10b, the exposed part17may have a height in the range of 1 mm to 5 mm. When the cleaning member10is used for the nodules10a, the exposed part17may have a height in the range of 1 mm to 3 mm.

As shown inFIGS. 7(a) and 7(b), the cleaning member10may have a base surface18. The base surface18may not be covered with the skin layer11. As shown inFIG. 7(b), a circumferential part19on the base end side may not be covered with the skin layer11and the sponge part12may be exposed in the circumferential part19.

The tip part of the cleaning member10may have a larger cross section (a horizontal cross section) in the part near the tip than in the part near the base. For example, as shown inFIGS. 5(b), 5(c), and 5(d), the tip part of the cleaning member10may be tapered toward the tip and have a trapezoidal vertical cross section. Alternatively, as shown inFIGS. 5(e), 5(f), and 5(g), the tip part of the cleaning member10may be stepped decreasingly toward the tip to have a stepped vertical cross section. The tip part of the cleaning member10may have a smaller cross section in the exposed part17than in the covered part16. For example, the tip part of the cleaning member10may have a cross section continuously or intermittently decreasing from the border between the exposed part17and the covered part16toward the tip in the exposed part17(SeeFIGS. 5(b) and 5(f)). Alternatively, the tip part of the cleaning member10may have a cross section continuously or intermittently decreasing from the tip side position relative to the border between the exposed part17and the covered part16toward the tip in the exposed part17(SeeFIGS. 5(c) and 5(e)). Alternatively, the tip part of the cleaning member10may have a cross section continuously or intermittently decreasing from the base side position relative to the border between the exposed part17and the covered part16toward the tip in the exposed part17(SeeFIGS. 5(d) and 5(g)).

As shown inFIG. 6, the cleaning member10is subjected to the friction with a substrate W in the direction opposite to the moving direction while cleaning the substrate W. The tip part of the cleaning member10is thus pulled in the direction opposite to the moving direction. If the circumferential part of the tip part of the cleaning member10is covered with the skin layer11to the tip end, the skin layer11is pulled in the direction opposite to the moving direction and causes contact contaminants on the substrate W (SeeFIG. 12, for example).

The advantageous effects of the embodiments having the above characteristics and especially the advantageous effects that have not been described yet will now be described.

In the above embodiment, the cleaning member10has the tip surface13without the skin layer11; and the circumferential part having the covered part16with the skin layer11on the circumferential surface, which is disposed on the base end side, and the exposed part17without the skin layer11on the circumferential surface, which is disposed on the tip end side. The cleaning member10can prevent particles in cleaning liquid from coming inside as much as possible; and can prevent the contact of the skin layer with the substrate. As a result, the cleaning member10can prevent particles in cleaning liquid from contaminating the substrate W and can prevent the contact contamination due to the contact of the skin layer11with the substrate W. Especially in a final cleaning, even the contact contamination may be a problem. In this respect, this embodiment is advantageous because the contact contamination can be prevented.

It is obvious by comparingFIGS. 8 and 10illustrating the sponge part12andFIGS. 9 and 11illustrating the skin layer11that the sponge part12has a higher porosity than the skin layer11. Therefore, the sponge part12hardly cause contact contamination while scrubbing a substrate W for cleaning.

In the above aspect, the exposed part17has a height equal to or more than the length of compression by which the cleaning member10can be compressed at the time of compression, which surely prevents the skin layer11on the side surface from going into the contact surface for the substrate W and from causing contact contamination.

If the exposed part17has a too small height, the skin layer11will cause contact contamination. Taking this into consideration, it is advantageous that the exposed part17has a height of 1 mm or more. If the exposed part17has a too great height, particles in cleaning liquid will go into the cleaning member10and then go to a substrate and adhere to the substrate. In addition, the exposed part17with a too great height may not have strength enough to keep the cleaning properties. Taking these into consideration, it is advantageous that the exposed part17has a height of 5 mm or less. When the cleaning member10is used for the nodules10a, each of which is subjected to a relatively small force, the exposed part17may have a height of 3 mm or less.

When cleaning liquid is supplied through the base surface18, cleaning liquid from the base surface18can selectively be supplied to a substrate through the exposed part17, which is advantageous. For example, cleaning liquid is supplied into the cylindrical body/bodies of the first roller-type cleaning member52and/or the second roller-type cleaning member53and then supplied to a substrate W from the tip ends of the nodules while the nodules are cleaning the substrate W (SeeFIG. 2). In this respect, when the base surface18is not covered with the skin layer11as shown inFIGS. 7(a) and 7(b), cleaning liquid can be taken into the cleaning member10through the base surface18and then efficiently be supplied to a substrate through the tip surface13and the exposed part17on the tip end side of the cleaning member10, which is advantageous. Especially when the base part has the circumferential part19without the skin layer11and the sponge part12is exposed in the circumferential part19as shown inFIG. 7(b), cleaning liquid can easily be taken into by the exposed sponge part12, which is advantageous.

When the tip part of the cleaning member10has a smaller cross section (a horizontal cross section) in the part near the tip than in the part near the base as shown inFIG. 5(b) to 5(g), the deformation of the cleaning member10can be restricted and thus the force applied to a substrate can be stabilized, which is advantageous. In this embodiment, since the exposed part17without the skin layer11on the circumferential surface is disposed on the tip end side, the cleaning member10can easily spread at the tip end. This embodiment is very advantageous for stabilizing the force applied to a substrate.

When the tip part of the cleaning member10is tapered and have a trapezoidal vertical cross section as shown inFIGS. 5(b), 5(c), and 5(d), the cleaning member10is advantageously tapered gradually toward the tip, which is easily deformed. When the tip part of the cleaning member10is stepped decreasingly toward the tip to have a stepped vertical cross section as shown inFIGS. 5(e), 5(f), and 5(g), the cleaning member10can advantageously change its shape toward the tip, which is easily deformed.

When the tip part of the cleaning member10has a cross section continuously or intermittently decreasing from the border between the exposed part17and the covered part16toward the tip in the exposed part17as shown inFIGS. 5(b) and 5(f), the cleaning member10can easily be manufactured by partially removing the skin layer11on the tip end side, which is advantageous. When the tip part of the cleaning member10has a cross section continuously or intermittently decreasing from the tip side position relative to the border between the exposed part17and the covered part16toward the tip in the exposed part17as shown inFIGS. 5(c) and 5(e), the cross section of the exposed part17, which is easily deformed, can surely be reduced, which is advantageous. When the tip part of the cleaning member10has a cross section continuously or intermittently decreasing from the base side position relative to the border between the exposed part17and the covered part16toward the tip in the exposed part17as shown inFIGS. 5(d) and 5(g), the deformation of the exposed part17can be restricted, which is advantageous.

Lastly, descriptions on the aforementioned embodiment as well as disclosed drawings are merely examples for describing the invention described in CLAIMS. The descriptions on the aforementioned embodiment or disclosed drawings should not be construed to limit the invention described in CLAIMS.

DESCRIPTION OF REFERENCE NUMERALS