JP2007287993A - Polishing head in chemical mechanical polishing (cmp) polishing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing head in a CMP polishing device, which will disengage a polished wafer in a moment that is absorbed and held by itself. <P>SOLUTION: The present invention is to provide a polishing head in a CMP polishing device, in which a plurality of zone air-bags 32 prepared in an air room 29 between a carrier 8 for a polishing head 3 and an elastic sheet 11 are inflated by a low pressure with approximately 1psi or less through a command signal from a controller, and a small open space is formed among a wafer W located between respective zone air-bags 32, the elastic sheet 11, and the carrier 8 to terminate the vacuum state, thereby causing a jet of an air blow or DIW to function momentarily and effectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polishing head in a CMP polishing apparatus, and more particularly to a polishing head in a CMP (Chemical Mechanical Pplising) polishing apparatus in which a polished wafer can be immediately detached from the polishing head.

As a polishing head in a conventional CMP polishing apparatus of this type, for example, the one described in Patent Document 1 is known. Thus, the polishing head described in the document 1 divides the air chamber provided on the lower surface of the carrier into a plurality of zones, that is, the central portion and the outer portion, and the zone air bag is provided in each zone. Is formed. Each zone air bag is configured such that air is individually supplied from the air supply path and is independently expanded and contracted. Therefore, by supplying air to each air bag and expanding the air bag individually, different pressing force of the zone air bag is applied to the wafer surface to be polished through the elastic sheet stretched on the lower surface of the carrier. On the other hand, the wafer is polished. Thus, the processing amount of the film thickness of the wafer is changed, and the film thickness of the wafer can be uniformly polished.
Japanese Patent No. 3683149 (see paragraph 0021, FIG. 4)

  The polishing head of the CMP polishing apparatus described in the above cited reference 1 is configured to press and polish the wafer to be polished by the air pressure from the air float line onto the polishing pad attached to the upper surface of the polishing platen. Has been. On the other hand, in particular, in the polishing head described in the cited document 1, a plurality of air bags are provided on the lower surface of the carrier, and air is injected into each air bag to inflate and press the wafer with different pressing forces. The air bag is configured to uniformly polish the film thickness of the wafer, and the air bag is used only in the wafer polishing operation. That is, the air bag is used only when the air is injected to expand each of the air bags and when the wafer is polished by applying a different pressing force to the wafer.

  Thus, the wafer is polished using the polishing head described in Patent Document 1 and the polishing head of other general CMP polishing apparatuses, and the polished wafer is adsorbed and held by the action of the vacuum line of the polishing head. The polished wafer is transported onto the polished wafer mounting table, where the polished wafer is detached from the polishing head by releasing the vacuum line of the polishing head and mounted on the polished wafer mounting table. The polishing head from which the polished wafer has been detached holds the unpolished wafer waiting on the unpolished wafer mounting table by the action of the vacuum line, carries it to the upper surface of the polishing platen, and adheres to the upper surface of the polishing platen It is mounted on the polishing pad and polished.

  Thus, when the polished wafer is detached from the polishing head and placed on the polished wafer mounting table, the conventional polishing head ejects the blown wafer from the polishing head by blowing air blow or DIW. At this time, air blow or DIW jet is not blown directly onto the polished wafer, but is blown onto the elastic sheet, and air or DIW leaking from the holes opened in the elastic sheet reaches the polished wafer. Since the polished wafer is detached from the polishing head, the waiting time until the polished wafer is reliably detached from the polishing head is increased, and the unpolished wafer is loaded by the polishing head from which the polished wafer is detached. There was a defect that the process until receiving an unpolished wafer waiting on the pedestal also becomes long.

  It is also possible to incorporate a rod that is driven by an air cylinder or the like into the polishing head, and forcibly push off the polished wafer. However, the force is applied by directly touching the polished wafer, which damages the polished wafer. There is a possibility of damage or breakage.

  Therefore, in the CMP polishing apparatus, there arises a technical problem to be solved in order to enable the polished wafer to be detached from the polishing head holding the polished wafer by suction in as short a time as possible. The present invention aims to solve this problem.

  The present invention has been proposed to achieve the above object, and the invention according to claim 1 is a polishing head of a CMP polishing apparatus, wherein the polishing head is rotatably provided, and the head The carrier is located at the lower part of the main body and rotates coaxially with the head main body. The head main body and the carrier are provided with an air float line and a vacuum line. An elastic sheet is stretched, an air chamber is provided between the elastic sheet and the carrier, and an air float line and / or a DIW feeding line and a vacuum line communicate with the air chamber, and the elastic sheet A hole is opened in the hole, and the wafer on the lower surface of the elastic sheet is adsorbed by the vacuum from the vacuum line through the hole, or the air The wafer is configured to be pressed onto a polishing pad adhered to a polishing platen by air pressure from a gate line. Further, the air chamber is divided into a plurality of pressing zones, and each pressing zone is divided into a plurality of pressing zones. In a polishing head configured to provide a zone air bag and control the pressing force and pressing time of each zone air bag to uniformly polish the film thickness of the wafer, the zone air bag is controlled by a command signal from the control unit. The wafer is configured to be expanded at a predetermined low pressure even when the polished wafer is detached from the polishing head, and the wafer / elastic sheet positioned between the zone airbags expanded at the low pressure and the carrier between the zone airbags. A space is formed between them, and the polished wafer is immediately separated from the polishing head by air blow and / or DIW ejection. There is provided a polishing head in configured CMP polishing apparatus as possible.

  According to this configuration, the zone air bag of the polishing head is inflated at a low pressure when the polished wafer is detached from the polishing head by the command signal from the control unit, so that the wafer is elastic between the zone air bags. A space is generated between the sheet and the carrier, and air blow or DIW jet functions effectively in a short time.

  According to a second aspect of the present invention, the zone airbag at the time of peeling the polished wafer from the polishing head is inflated at a low pressure of about 1 psi or less by a command signal from the control unit. A polishing head in an apparatus is provided.

  According to this configuration, the zone airbag at the time of peeling the polished wafer from the polishing head expands at a low pressure of about 1 psi or less by a command signal from the control unit.

According to a third aspect of the present invention, there is provided a polishing head of a CMP polishing apparatus, wherein the polishing head includes a head body that is rotatably provided, and a carrier that is disposed below the head body and rotates coaxially with the head body. And an air float line and a vacuum line are provided on the head body and the carrier, and an elastic sheet is stretched on the lower surface of the carrier, and between the elastic sheet and the carrier. An air chamber is provided, and an air float line and / or a DIW feeding line and a vacuum line are communicated with the air chamber, and a hole is opened in the elastic sheet, and a bottom surface of the elastic sheet is formed through the hole. The wafer is adsorbed by vacuum from the vacuum line, or the wafer is polished by air pressure from the air float line. In the polishing head configured to be able to be pressed onto the polishing pad attached on the surface, the elastic sheet also serves as a DIW feed line extending to the carrier. Provided is a polishing head in a CMP polishing apparatus in which a blowout hole for blowing out air and / or DIW blown out from an air blowout port is provided immediately below an air blowout port of an air float line.

  According to this configuration, the air or DIW blown from the air blowing port of the air float line that also serves as the DIW supply line is directly sprayed onto the polished wafer, and the polished wafer is separated from the polishing head.

  In the first aspect of the invention, when the polished wafer is detached from the polishing head, an interlock portion is provided in the control portion so that a plurality of zone airbags provided between the carrier and the elastic sheet can be expanded at a low pressure. ing. Therefore, the zone air bag is not inflated at a high pressure higher than a predetermined low pressure by the interlock. Therefore, the zone air bag expands like a balloon and applies an excessive force to the elastic sheet to retain the ring. There is no damage or rupture of the zone air bag itself, and a slightly swelled zone air bag forms a small space between the carrier and the wafer / elastic sheet between the zone air bags and vacuum suction The state is released.

  Therefore, the polished wafer can be detached from the polishing head in a very short time by jetting air float or DIW. Thus, the efficiency of a series of wafer polishing operations by the CMP polishing apparatus is improved, which contributes to cost reduction.

  In the invention according to claim 2, the zone air bag is inflated at a low pressure of about 1 psi or less by the interlock portion provided in the control portion, so that it is polished on the lower surface of the elastic sheet by air blow or DIW jet. An appropriate space for detaching the wafer from the polishing head in an extremely short time is maintained, and the effect produced by the invention of claim 1 can be realized most efficiently.

  In the invention according to claim 3, since an air or DIW ejection hole is opened in a portion of the elastic sheet located immediately below the air blowing port of the air float line that also serves as a DIW feeding line, The jetted air or DIW is immediately sprayed directly onto the polished wafer on the lower surface of the elastic sheet through the jetting holes, so that the polished wafer can be detached from the polishing head in a very short time. Thus, the wafer polishing operation by the CMP polishing apparatus can be performed efficiently, which contributes to cost reduction.

  The present invention is a polishing head in a CMP polishing apparatus, which holds a polished wafer by suction and carries it to a polished wafer mounting table, where it is possible to remove the polished wafer from the polishing head. In order to achieve the purpose of separating in a short time, a plurality of zone airbags provided in the air chamber between the carrier of the polishing head and the elastic sheet are reduced to about 1 psi or less by a command signal from the control unit. The air is blown up to form a small space between the wafer / elastic sheet and the carrier located between each zone air bag, and the vacuum state is released, so that air blow or DIW jetting is effective in a short time. The present invention has been realized by providing a polishing head in a CMP polishing apparatus adapted to function.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 is a perspective view showing an outline of the wafer polishing apparatus 1. In the figure, the wafer polishing apparatus 1 mainly comprises a polishing platen 2 and a polishing head 3.

  Thus, the polishing platen 2 is formed in a disc shape, and a rotating shaft 4 is connected to the center of the lower surface thereof, and rotates in the direction of arrow A by driving of the motor 5. A polishing pad 6 is attached to the upper surface of the polishing platen 2, and an abrasive (slurry) is supplied onto the polishing pad 6 from a nozzle (not shown).

  As shown in FIG. 2, the polishing head 3 is mainly composed of a head body 7, a carrier 8, a retainer ring 9, a retainer ring pressing means 10, an elastic sheet 11, a carrier pressing means 16, and control means such as air. .

  The head body 7 is formed in a disk shape, and a rotary shaft 12 (see FIG. 1) is connected to the center of the upper surface thereof. The head body 7 is attached to the rotary shaft 12 and driven by a motor (not shown) to rotate in the direction of arrow B in FIG.

  The carrier 8 is formed in a disc shape and is arranged at the lower center of the head body 7. Further, a dry plate 13 is provided between the center of the upper surface of the carrier 8 and the lower center of the head body 7, and the rotation is transmitted from the head body 7 via the pins 14. An operation transformer main body 15a is fixed between the center lower portion of the dry plate 13 and the center upper portion of the carrier 8, and the core 15b of the operation transformer 15 is fixed to the center upper portion of the carrier 8, and a control unit. It is connected to (not shown) and outputs a polishing state signal of the wafer W to the control unit.

  A carrier pressing member 16a is provided on the peripheral edge of the upper surface of the carrier 8, and the carrier 8 receives a pressing force from the carrier pressing means 16 through the carrier pressing member 16a.

  An air outlet 19 for injecting air from the air float line 17 to the elastic sheet 11 is provided on the lower surface of the carrier 8. The air float line 17 is connected to an air supply pump 20 as an air supply source via an automatic opening / closing valve V1. Air is blown out from the air outlet 19 by switching the automatic opening / closing valve V1. If necessary, the air float line 17 also serves as a DIW (pure water) 21 supply line. Therefore, the air outlet 19 also serves as a DIW 21 outlet if necessary.

  The carrier 8 is provided with a vacuum port 19 a communicating with the vacuum line 24, and the elastic sheet 11 stretched on the lower surface of the carrier 8 has a hole 22 communicating with the vacuum line 24. Is provided. The suction of the air is performed by driving the vacuum pump 23, the automatic opening / closing valve V2 is provided in the vacuum line 24, and the vacuum is executed via the vacuum line 24 by switching the automatic opening / closing valve V2.

  Further, the air supply from the air float line 17, the vacuum action from the vacuum line 24, the DIW supply, etc. are executed by command signals from the control unit.

  The carrier pressing means 16 is disposed at the peripheral edge of the central portion of the lower surface of the head main body 7 and applies a pressing force to the carrier pressing member 16a, thereby transmitting the pressing force to the carrier 8 coupled thereto. The carrier pressing means 16 is preferably composed of a rubber sheet airbag 25 that expands and contracts by air intake and exhaust. An air supply mechanism (not shown) for supplying air is connected to the airbag 25.

  The retainer ring 9 is formed in a ring shape and is disposed on the outer periphery of the carrier 8. The retainer ring 9 is attached to a retainer ring holder 27 provided on the polishing head 3, and the elastic sheet 11 is stretched on the inner peripheral portion thereof.

  Furthermore, the elastic sheet 11 is formed in a circular shape, and a plurality of holes 22 are opened. The elastic sheet 11 is stretched on the inner side of the retainer ring 9 by sandwiching the peripheral edge portion between the retainer ring 9 and the retainer ring holder 27.

  An air chamber 29 is formed between the carrier 8 and the elastic sheet 11 below the carrier 8 on which the elastic sheet 11 is stretched. The wafer W is pressed against the carrier 8 through the air chamber 29. The retainer ring holder 27 is attached to an attachment member 30 formed in a ring shape via a snap ring 31. A retainer ring pressing member 10 a is connected to the mounting member 30. The retainer ring 9 is transmitted with the pressing force from the retainer ring pressing means 10 via the retainer ring pressing member 10a.

  The retainer ring pressing means 10 is disposed on the outer peripheral portion of the lower surface of the head body 7, and applies a pressing force to the retainer ring pressing member 10 a to press the retainer ring 9 coupled thereto against the polishing pad 6. This retainer ring pressing means 10 is also preferably composed of a rubber sheet airbag 25a, like the carrier pressing means 16. An air supply mechanism (not shown) for supplying air is connected to the airbag 25a.

  Hereinafter, a procedure for polishing the wafer W by the wafer polishing apparatus 1 of the present invention will be briefly described. First, the polishing head 3 is moved to a predetermined position on a non-polishing wafer on standby by a moving mechanism (not shown) and placed on the upper surface of the non-polishing wafer. Then, the vacuum line 24 of the polishing head 3 is actuated to evacuate the lower surface of the elastic sheet 11 through a vacuum port 19a provided in the carrier 8, thereby sucking and holding the non-polished wafer, and by the moving mechanism Then, the polishing head 3 holding the non-polishing wafer by suction is carried onto the polishing platen 2 and the non-polishing wafer is placed on the polishing pad 6 stuck on the polishing platen. Further, when the polishing operation of the wafer W is finished, the vacuum line 24 is again sucked and held by the polishing head 3 by the operation of the vacuum line 24 and transported to the polished wafer mounting table (not shown). It is also used when

  Next, the operation of the vacuum line 24 is released to release the suction of the unpolished wafer, and air is supplied to the airbags 25 and 25a from a pump (not shown) to inflate the airbags 25 and 25a. At the same time, air is supplied to the air chamber 29 from the air outlet 19 provided in the carrier 8. Thereby, the internal pressure of the air chamber 29 becomes high.

  The wafer W and the retainer ring 9 are pressed against the polishing pad 6 with a predetermined pressure by the expansion of the airbags 25 and 25a. In this state, the polishing platen 2 is rotated in the direction of arrow A in FIG. 1, and the polishing head 3 is rotated in the direction of arrow B in FIG. Then, slurry is supplied from a nozzle (not shown) onto the rotating polishing pad 6 so that the lower surface of the wafer W is polished by the polishing pad 6.

Next, an essential part of the invention described in claims 1 and 2 will be described with reference to FIG. In the above-described invention, the zone airbags 32 are provided on the left and right sides of the central portion of the air chamber 29 formed between the carrier 8 and the elastic sheet 11, respectively. An air supply line 33 is connected to each of the zone airbags 32 so that air can be supplied and expanded independently. Further, the supply of air to the zone airbag 32 is executed by a command signal from the controller, and thus each of the swollen zone airbags exerts different pressing forces on the surface to be polished of the wafer W to be polished. The wafer is applied to press the wafer, and the film thickness of the wafer can be uniformly polished.

  Thus, a software interlock unit (not shown) that allows the zone airbag 32 to be inflated only with a predetermined low pressure (about 1 psi or less) is provided in the control unit. Therefore, the zone airbag 32 can be inflated at about 1 psi or less, and a higher pressure is restricted by the interlock portion. Therefore, when the polished wafer W is separated from the polishing head 3 that holds the polished wafer W by suction, the zone airbag 32 is first inflated at the low pressure to be positioned between the zone airbags 32. Since a slight space is formed between the wafer W / elastic sheet 11 to be carried out and the carrier 8, mutual suction by the vacuum in this space is canceled in advance.

  Therefore, if air or DIW is ejected from the air blowing port 19 communicating with the air float line 17, the polished wafer W on the lower surface of the elastic sheet 11 is immediately removed from the suction by the polishing head 3 and removed in a very short time. Can.

  Next, an embodiment of the invention described in claim 3 will be described with reference to FIG. As shown in the figure, a vacuum port 19a communicated with a vacuum line 24 is provided in the vicinity of both left and right ends of the carrier 8, and the air chamber 29 is evacuated by the action of the vacuum line from the vacuum port 19a. The lower surface of the elastic sheet 11 is also evacuated through the holes 22 provided in the elastic sheet 11, the wafer W is attracted to the elastic sheet 11, and the wafer W is held by the polishing head 3. Then, the polished wafer W is detached from the polishing head 3 and placed on the polished wafer mounting table. Thus, the vacuum line 24 is used when the wafer W is delivered between the polished wafer mounting table, the unpolished wafer mounting table, and the polishing platen 2.

  In addition, air float lines 17 that also serve as DIW supply lines are disposed on the left and right sides of the center portion of the carrier 8, and an air outlet 19 that also serves as a DIW outlet is provided in the air float line 17. . The air blown from the air blowing port 19 applies air pressure to the air chamber 29 between the carrier 8 and the elastic sheet 11 to expand the elastic sheet 11, and the pressing force of the carrier 8 is expanded. The wafer W is indirectly loaded via the elastic sheet 11 and polishing of the wafer W is executed.

  On the other hand, DIW can also be ejected from the air outlet 19. In the present invention, in particular, the removal of the polished wafer W from the polishing head 3 is performed using DIW ejection, but of course, it can also be performed by air blowing.

  According to a third aspect of the present invention, a hole 34 is additionally opened in the elastic sheet 11 located immediately below the air outlet 19 that communicates with the air float line 17 that also serves as the DIW supply line. However, if the holes 34 are opened directly below all the air outlets 19, the elastic sheet 11 may not swell at the time of air float, or due to DIW between the elastic sheet 11 and the carrier 8. Because of the inconvenience that the cleaning cannot be performed, as described above, the hole 34 is additionally opened in the elastic sheet 11 facing the part of the air outlets 19 or the added air is added. It is possible to open the hole 34 in the elastic sheet 11 at a location facing the outlet 19. If this is the case, all the inconveniences can be eliminated.

Thus, in the invention described in claim 3, when the polished wafer W is detached from the polishing head 3, the vacuum is released, and if air or DIW is ejected from the air outlet 19, Air or DIW is directly sprayed onto the polished wafer W through the hole 34 opened in the elastic sheet 11, and the polished wafer W is detached from the polishing head 3 in an extremely short time. Then, the polishing head 3 from which the polished wafer W has been detached immediately moves onto the unpolished wafer mounting table, which is the next step, and sucks and holds the unpolished wafer W that is waiting on the vacuum platen 2. It becomes possible to carry on. Thus, the wafer polishing operation by the CMP polishing apparatus is performed very efficiently, which contributes to cost reduction.

  It should be noted that the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

1 is a perspective view of an entire wafer polishing apparatus according to an embodiment of the present invention. 1 is a longitudinal sectional view showing a polishing head of the present invention. The principal part of this invention is shown, and the description longitudinal cross-sectional view. The other principal part of this invention is shown, and the explanatory longitudinal cross-sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wafer polisher 2 Polishing platen 3 Polishing head 4,12 Rotating shaft 5 Motor 6 Polishing pad 7 Head main body 8 Carrier 9 Retainer ring 10 Retainer ring pressing means 10a Retainer ring pressing member 11 Elastic sheet 16 Carrier pressing means 16a Carrier pressing Member 17 Air float line 19 Air outlet 22 and 34 holes 24 Vacuum line 25 and 25a Air bag 29 Air chamber 32 Zone air bag

Claims (3)

A polishing head of a CMP polishing apparatus, the polishing head having a head body rotatably provided, a carrier at a lower part of the head body and rotating coaxially with the head body, and The head main body and the carrier are provided with an air float line and a vacuum line. Further, an elastic sheet is stretched on the lower surface of the carrier, and an air chamber is provided between the elastic sheet and the carrier. In addition, an air float line and / or a DIW feeding line and a vacuum line are connected to the air chamber, and a hole is opened in the elastic sheet, and a wafer on the lower surface of the elastic sheet is removed from the vacuum line through the hole. The wafer is adsorbed by a vacuum or attached to the polishing platen by the air pressure from the air float line. The air chamber is divided into a plurality of pressing zones, and zone air bags are provided in each pressing zone to control the pressing force and pressing time of each zone air bag. In the polishing head configured to uniformly polish the film thickness of the wafer,
The zone air bag is configured to be able to expand at a predetermined low pressure even when the polished wafer is detached from the polishing head by a command signal from the control unit. A CMP is characterized in that a space is formed between the elastic sheet and the carrier between the zone air bags so that the polished wafer can be immediately detached from the polishing head by air blow and / or DIW ejection. A polishing head in a polishing apparatus.   The zone air bag at the time of peeling the polished wafer from the polishing head is configured to be inflated at a low pressure of about 1 psi or less by a command signal from a control unit. A polishing head in a CMP polishing apparatus.   A polishing head of a CMP polishing apparatus, the polishing head having a head body that is rotatably provided, a carrier that is located below the head body and rotates coaxially with the head body, and the head The main body and the carrier are provided with an air float line and a vacuum line, and further, an elastic sheet is stretched on the lower surface of the carrier, and an air chamber is provided between the elastic sheet and the carrier. An air float line and / or a DIW feed line and a vacuum line are connected to the air chamber, and a hole is opened in the elastic sheet, and a wafer on the lower surface of the elastic sheet is passed through the hole from the vacuum line. Adsorbed by vacuum, or the wafer is stuck on the polishing platen by air pressure from the air float line. A polishing head configured to be able to be pressed onto a polishing pad, wherein the elastic sheet is directly below an air outlet of an air float line that also serves as a DIW feeding line extending to the carrier. A polishing head in a CMP polishing apparatus, wherein a jet hole for jetting air and / or DIW blown from the air blowing port is opened.

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