JP2005074574A - Polishing device and polishing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing device and a polishing method which neither pollute a chuck surface of a conveying device for receiving a wafer after polished, with slurry and chips from polishing, nor reduce the cleaning efficiency of a washing device for washing the wafer after polished. <P>SOLUTION: Prior to the conveyance of a plate-like material W after polished to the washing device 40, the back face of the plate-like material W is subjected to shower washing and scrub washing by a pre-washing device 7 inside a delivery device 50 for receiving the plate-like material W from a polishing head 33 and delivering it to the conveying device 60, to wash away the slurry and polishing waste, stuck to the back face of the plate-like material W. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polishing apparatus and a polishing method, and more particularly to a polishing apparatus and a polishing method for polishing the surface of a plate-like material and then carrying the cleaned plate-like material into a cleaning device for cleaning.

  In recent years, with the development of semiconductor technology, design rules have been miniaturized and multilayered wiring has been progressed, and the wafer diameter has been increased in order to reduce costs. Therefore, when trying to form the pattern of the next layer as it is on the layer where the pattern is formed as in the past, it is difficult to form a good pattern in the next layer due to the unevenness of the previous layer, It was easy to occur.

  Therefore, the surface of the layer on which the pattern is formed is flattened, and then the pattern of the next layer is formed. In this case, a wafer polishing apparatus using a CMP (CMP: Chemical Mechanical Polishing) method is used.

  As a wafer polishing apparatus by this CMP method, it has a disk-shaped polishing surface plate with a polishing pad affixed to the surface, and a polishing head that holds one surface of the wafer and abuts the other surface of the wafer against the polishing pad. And a CMP apparatus for polishing the other surface of the wafer while rotating the polishing platen and rotating the polishing head to bring the wafer into contact with the polishing pad and supplying slurry as an abrasive between the polishing pad and the wafer. Generally known widely.

  A plurality of transfer devices for transferring a wafer are incorporated in the CMP apparatus, and the wafer is transferred to each part of the CMP apparatus by the plurality of transfer apparatuses and polished to flatten the surface. In addition, a wafer delivery stage is incorporated for delivering a wafer between one transfer device and another transfer device.

  The wafer delivery stage is a stage having a recess having a diameter slightly larger than the diameter of the wafer and having a water supply port provided on the bottom surface of the recess. When the wafer is received from the transfer device, the wafer is received at the bottom surface of the recess. A load stage has been proposed in which positioning is performed on the side of the wafer and water is supplied to the recess when the wafer is transferred to another transfer device, and the wafer is floated and lifted (see, for example, Patent Document 1).

The wafer that has been polished and whose surface is flattened is transferred from the polishing head onto the load stage, and is transferred from the load stage to a cleaning device by another transfer device. In the cleaning apparatus, the front and back surfaces of the wafer are cleaned, rinsed, and dried.
JP 2000-124174 A

  However, in the conventional wafer processing apparatus described in Patent Document 1 described above, the wafer whose surface is polished is transferred from the polishing head to the load stage, and then transferred to the next transfer apparatus and transferred to the cleaning apparatus. There, washing and drying are performed.

  However, the wafer whose surface is polished by being held by the polishing head on the back side is sprayed with pure water to the surface side while being held by the polishing head after polishing, and the slurry and polishing debris adhering to the surface are washed away. In this state, it is delivered to the load stage, but the slurry and polishing debris that has come around to the back surface of the wafer remain attached to the back surface of the wafer.

  For this reason, there has been a problem that the chuck surface of the conveying means is contaminated with slurry or polishing debris when it is transferred from the load stage to the next conveying means. In addition, when the slurry or polishing waste adhering to the chuck surface of the transport means is dried and fixed, if the next wafer is chucked with this chuck surface, the back surface of the chucked wafer is damaged. Furthermore, there has been a problem that the efficiency of the cleaning device is reduced by bringing a wafer with much dirt into the cleaning device.

  The present invention has been made in view of such circumstances, and does not contaminate the chuck surface of the transfer device that receives the polished wafer with slurry or polishing debris. An object of the present invention is to provide a polishing apparatus and a polishing method that can prevent the rear surface of the wafer from being scratched by polishing debris and that do not reduce the cleaning efficiency of the cleaning apparatus that cleans the polished wafer.

  In order to achieve the above object, the invention according to claim 1 is a polishing pad that rotates while holding the back surface of the plate-like material with a polishing head and rotates the surface of the plate-like material while interposing a slurry. In a polishing apparatus that presses and polishes the surface of the plate-like object, the polishing apparatus comprising a cleaning device that cleans the plate-like object after polishing, the plate-like object after polishing is transferred to the cleaning device. A pre-cleaning device is provided that cleans the back surface of the plate-like object before being conveyed.

  According to the first aspect of the present invention, the slurry and polishing dust adhered to the back surface of the plate-like material by washing the back surface of the plate-like material with the pre-cleaning device before conveying the polished plate-like material to the cleaning device. The chuck surface of the transfer device is not contaminated. Further, it is possible to prevent the back surface of the plate-like material from being scratched by the slurry or polishing dust adhered to the chuck surface of the transport device, and further, the cleaning efficiency of the plate-like material cleaning device after polishing is not reduced.

  According to a second aspect of the present invention, in the first aspect of the invention, the pre-cleaning device is provided in a delivery device that receives a plate-like object from the polishing head and delivers it to a conveying device.

  According to the invention of claim 2, since the back surface of the plate-like object is pre-cleaned in the transfer device that receives the plate-like object from the polishing head and delivers it to the transfer device, the back surface of the plate-like object is brought into contact with the chuck surface of the transfer device. Slurry and polishing waste adhering to the back surface before contact can be washed away, and the chuck surface of the transfer device is not contaminated.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the pre-cleaning device performs shower cleaning or scrub cleaning, or shower cleaning and scrub cleaning.

  According to the invention of claim 3, since the back surface of the plate-like material is pre-cleaned by shower cleaning or scrub cleaning, or shower cleaning and scrub cleaning, the slurry and polishing scraps adhering to the back surface can be efficiently washed away. Can do.

  According to a fourth aspect of the present invention, the polishing head holds and rotates the back surface of the plate-like object, and the surface of the plate-like object is pressed against the rotating polishing pad while the slurry is interposed, so that the plate A polishing method for polishing a surface of a plate-like object, wherein the plate-like material after polishing is cleaned with a cleaning device, and before the plate-like material after polishing is transported to a cleaning device, It is characterized by pre-cleaning the back surface.

  According to a fifth aspect of the invention, in the fourth aspect of the invention, the pre-cleaning is performed in a delivery device that receives a plate-like object from the polishing head and delivers it to a conveying device. The invention described in any one of claims 4 and 5 is characterized in that in the pre-cleaning, shower cleaning or scrub cleaning, or shower cleaning and scrub cleaning is performed.

  According to the present invention, the back surface of the plate-like material is washed with the pre-cleaning device before the polished plate-like material is transferred to the cleaning device, and the slurry and polishing scraps adhered to the back surface of the plate-like material are washed away. Therefore, the chuck surface of the transfer device is not contaminated. In addition, it is possible to prevent the back surface of the plate-like material from being scratched by slurry or polishing debris adhered to the chuck surface of the conveying device, and further, the cleaning efficiency of the cleaning device for cleaning the plate-like material after polishing is not reduced. .

  In addition, since the back surface of the plate-like object is pre-cleaned in the transfer device that receives the plate-like material from the polishing head and delivers it to the transport device, it adheres to the back surface before it contacts the chuck surface of the transport device. The slurry and polishing scraps that have been removed can be washed away, and the chuck surface of the transfer device is not contaminated.

  Further, since the back surface of the plate-like material is pre-cleaned by shower cleaning or scrub cleaning, or shower cleaning and scrub cleaning, the slurry and polishing debris adhered to the back surface can be efficiently washed away.

  The best mode for carrying out the polishing apparatus and polishing method according to the present invention will be described in detail below with reference to the accompanying drawings. In addition, in each figure, the same number or the code | symbol is attached | subjected about the same member.

  1 and 2 are configuration diagrams illustrating an embodiment of a polishing apparatus according to the present invention. FIG. 1 is a plan view and FIG. 2 is a front view.

  The polishing apparatus 10 includes a wafer storage unit 20 that stores a wafer W that is a plate-like object, a polishing unit 30 that polishes the wafer W, a cleaning apparatus 40 that cleans and dries the polished wafer W, and a wafer when the wafer W is transported. A transfer device 50 for transferring W, a transfer device 60 for the wafer W, a pre-cleaning device 70 for pre-cleaning the back surface of the wafer W, and the like.

  The wafer storage unit 20 stores a supply cassette 21 that stores a large number of wafers W and a storage cassette 22 that stores the polished wafers W.

  As shown in FIGS. 1 and 2, the polishing unit 30 has a polishing pad 32 attached to the upper surface, is rotated by a polishing surface plate 31 rotated by a driving device (not shown), and the rear surface of the wafer W, and is rotated while the wafer is rotated. A polishing head 33 that presses the surface of W against the polishing pad 32, a slurry nozzle 34 that supplies polishing slurry while swinging on the upper surface of the polishing pad 32, and the like.

  The polishing head 33 is movable between the polishing position of the polishing unit 30 and the transfer position of the wafer W transfer device 50, receives the wafer W on the transfer device 50, and transfers the polished wafer W to the transfer device 50. Deliver.

  The cleaning apparatus 40 performs alkali cleaning, acid cleaning, rinsing, and spin drying of the polished wafer W. The transfer device 50 has a wafer cup 51 having an inner diameter slightly larger than the outer diameter of the wafer W, receives the wafer W from the transfer device 60 and transfers it to the polishing head 33, and also transfers the polished wafer W to the polishing head 33. It is received from the polishing head 33 and transferred to the transfer device 60.

  Pure water is stored in the wafer cup 51, and when the wafer W is received, the impact is suppressed on the water surface. Further, when the wafer W is delivered, the stored pure water is drained, and the wafer W is delivered while being supported by a plurality of support members 51A, 51A,... Provided at the bottom of the wafer cup 51. . It is preferable that six to eight support members 51A are arranged at equal intervals on the circumference.

  The transfer device 60 has a multi-indirect arm 61 with a suction pad 62 attached to the tip, sucks the wafer W by the chuck surface 62A of the suction pad 62, supplies the cassette 21, the transfer device 50, the cleaning device 40, and the storage. Wafers W are transferred between the cassettes 22.

  A pre-cleaning device 70 is provided above the delivery device 50. The pre-cleaning device 70 has a shower nozzle 71 and a rotating brush 72. The shower nozzle 71 reciprocates in the radial direction of the wafer W and jets pure water downward from the tip.

  The brush 72 is formed of a cylindrical nylon brush or sponge, and rotates while causing pure water to flow from the shaft core and reciprocates in the radial direction of the wafer W. The brush 72 is not limited to a cylindrical shape, and may be a cup-type brush.

  The pre-cleaning device 70 performs shower cleaning by reciprocating the shower nozzle 71 while spraying pure water from the shower nozzle 71 onto the back surface of the wafer W held by the delivery device 50 and rotating the rotating brush 72 to rotate the back surface. The back surface of the wafer W is scrubbed by abutting it. In this way, the slurry and polishing debris adhering to the back surface of the wafer W are washed away by shower cleaning and scrub cleaning by the pre-cleaning device 70.

  Next, the operation of the polishing apparatus 10 configured as described above will be described. A supply cassette 21 storing a plurality of wafers W to be polished and an empty storage cassette 22 storing the polished wafers W are set in the wafer storage unit 20.

  Next, the first wafer W is taken out from the supply cassette 21 by the transfer device 60 and transferred to the transfer device 50. Pure water is stored in the wafer cup 51 of the delivery device 50, and the wafer W is softly received on the water surface and the wafer W is centered. At this time, the surface side of the wafer W to be polished is facing downward and in contact with the water surface.

  Next, the pure water in the wafer cup 51 is discharged, and the wafer W is supported by a plurality of support members 51A, 51A,. Here, the polishing head 33 moves above the delivery device 50, moves to the upper surface of the polishing pad 32 while holding the back surface of the wafer W by suction.

  When the polishing head 33 receives the wafer W from the transfer device 50, since the pure water in the wafer cup 51 is discharged, the surface tension due to the pure water does not act on the wafer W, and the wafer W can be received smoothly.

  Here, the wafer W is pressed while rotating on the rotating polishing pad, and the surface is polished. In polishing, a chemical slurry containing an abrasive is supplied from the oscillating slurry nozzle 34 to the upper surface of the polishing pad 32, and the surface of the wafer W is flattened by chemical mechanical polishing by the CMP method. When the polishing is completed, pure water is jetted onto the surface of the polished wafer W from a pure water nozzle (not shown), and slurry and polishing debris are washed away from the surface.

  Next, the polishing head 33 moves above the transfer device 50, releases the suction, and transfers the polished wafer W into the wafer cup 51 in which pure water is stored. The wafer W is cleaned with pure water while being held by the polishing head 33 after polishing, and the slurry and polishing debris on the surface are removed. During the polishing, the wafer suction surface of the polishing head 33 and the back surface of the wafer W are removed. Since the slurry and the polishing dust that have entered the slight gap between them are not removed, the slurry and the polishing dust remain attached to the back surface of the wafer W transferred to the transfer device 50.

  Here, the pre-cleaning apparatus 70 is activated. That is, the shower nozzle 71 reciprocates in the radial direction of the wafer W, sprays pure water onto the back surface of the wafer W to perform shower cleaning, and the rotating brush 72 rotates and reciprocates while discharging pure water from the shaft core. Then, scrub cleaning is performed to wash away slurry and polishing debris adhering to the back surface of the wafer W.

  Next, the pure water in the wafer cup 51 is discharged and the wafer W is adsorbed to the suction pad 62 of the transfer device 60 while being supported by the plurality of support members 51A, 51A,. .

  At this time, since the back surface of the wafer W is cleaned by the pre-cleaning device 70, the suction surface 62A of the suction pad 62 of the transfer device 60 is not contaminated. Further, it is possible to prevent a large amount of dirt from being brought into the cleaning device 40.

  In the cleaning apparatus 40, scrub cleaning and rinsing with a PVA (polyvinyl alcohol) brush, scrub cleaning and rinsing with an acidic chemical and brush, and metal contamination removal while supplying an alkaline chemical to both the front and back surfaces of the wafer W Chemical spin cleaning, pure water megasonic spin cleaning with ultrasonic waves, spin drying with nitrogen gas, and the like are performed, and the wafer W is completely cleaned and dried. In this cleaning apparatus 40, since the wafer W is loaded with as little dirt as possible, the cleaning efficiency is high.

  The wafer W completely cleaned and dried by the cleaning device 40 is finally stored in the storage cassette 22 by the transfer device 60. The suction pad 62 of the transfer device 60 is previously cleaned with pure water sprayed from a cleaning nozzle (not shown) so as not to contaminate the cleaned wafer W. The above is the flow of one wafer W in the polishing apparatus 10 according to the present invention.

  In the above-described embodiment, the pre-cleaning apparatus 70 is configured with the shower nozzle 71 for shower cleaning and the rotary brush 72 for scrub cleaning. However, the present invention is not limited to this, and the shower nozzle 71 and the rotation are not limited thereto. Only one of the brushes 72 may be used, and other cleaning means such as megasonic cleaning may be used instead of shower cleaning or scrub cleaning.

The top view showing the polish device concerning an embodiment of the invention The partial front view showing the polish device concerning an embodiment of the invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Polishing apparatus, 32 ... Polishing pad, 33 ... Polishing head, 40 ... Cleaning apparatus, 50 ... Delivery apparatus, 60 ... Conveyance apparatus, 70 ... Pre-cleaning apparatus, W ... Wafer (plate-shaped object)

Claims (6)

A polishing apparatus that holds and rotates the back surface of the plate-like object with a polishing head and polishes the surface of the plate-like object by pressing the surface of the plate-like object against a rotating polishing pad while interposing a slurry. In a polishing apparatus provided with a cleaning device for cleaning the plate-like material after polishing,
A polishing apparatus, comprising: a pre-cleaning device that cleans the back surface of the plate-shaped object before the polished plate-shaped object is conveyed to the cleaning device.   The polishing apparatus according to claim 1, wherein the pre-cleaning device is provided in a transfer device that receives a plate-like object from the polishing head and transfers the plate-like object to a conveying device.   The polishing apparatus according to claim 1, wherein the pre-cleaning apparatus performs shower cleaning or scrub cleaning, or shower cleaning and scrub cleaning. In this polishing method, the back surface of the plate-like object is held by the polishing head and rotated, and the surface of the plate-like object is pressed against the rotating polishing pad while the slurry is interposed, thereby polishing the surface of the plate-like object. In the polishing method of cleaning the plate-like material after polishing with a cleaning device,
A polishing method comprising pre-cleaning the back surface of the plate-like material before conveying the plate-like material after polishing to a cleaning device.   The polishing method according to claim 4, wherein the pre-cleaning is performed in a delivery device that receives a plate-like object from the polishing head and delivers the plate-like material to a conveying device.   6. The polishing method according to claim 4, wherein in the pre-cleaning, shower cleaning or scrub cleaning, or shower cleaning and scrub cleaning is performed.

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