JP2010274408A - Conditioner of polishing pad - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conditioner capable of avoiding a drop in polishing performance due to clogging of surface pores on a polishing pad and wear on the polishing pad surface with a simple structure, and also grinding the polishing pad so that the polishing pad surface has desired surface roughness for precision polishing of a semiconductor substrate. <P>SOLUTION: The conditioner 10 includes a conditioning part 11 coming into contact with the polishing pad surface for grinding and a support 12 for supporting the conditioning part 11. The support 12 includes an elastic cushion layer 122. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a conditioner for a polishing pad used for planarization polishing of a semiconductor substrate in a semiconductor device manufacturing process.

  An example of a polishing pad used for planarization polishing of a semiconductor substrate is a polishing pad made of foamed polyurethane. This polishing pad has a number of independent pores, and is configured to polish the surface of the semiconductor substrate by holding an abrasive in the pores exposed on the surface.

  When polishing the surface of a semiconductor substrate using such a polishing pad, the reaction product generated during polishing and the polishing agent itself are compressed into the pores existing on the surface of the polishing pad as the number of polishing increases. Then, it is trapped and fixed, and the clogging of the pores proceeds. Furthermore, during polishing, the polishing pad continues to receive simultaneously a compressive force from a direction perpendicular to the polishing surface and a shearing force due to friction from a direction parallel to the polishing surface, and the surface of the polishing pad has deteriorated. As a result, the polishing rate is lowered and the polishing uniformity is deteriorated.

  The conditioner of the polishing pad removes clogging caused by foreign matter adhering to the surface pores of the polishing pad, and also maintains and improves the surface performance of the polishing pad that polishes the semiconductor substrate with high precision. Is ground by a certain amount.

  As a conditioner that grinds the surface of the polishing pad, for example, Patent Document 1 includes a conditioning unit that grinds in contact with the surface of the polishing pad, and a space that is supplied with pressurized fluid, and supports the conditioning unit. There is disclosed a conditioner configured to include a supporting portion.

  The conditioner disclosed in Patent Document 1 supports the conditioning unit such that the support unit in a state where the pressurized fluid is supplied to the space unit is movable in a direction perpendicular to the polishing pad surface. Regardless of the shape, the pressing force in the direction perpendicular to the surface of the polishing pad can be controlled to be constant.

JP 2000-753 A

  However, in the conditioner disclosed in Patent Document 1, when the surface of the polishing pad to which the polishing liquid is supplied is ground, the abrasive grains contained in the polishing liquid enter the space portion of the support portion and enter the space portion. It may adhere to the wall surface. In such a case, the conditioning unit is prevented from moving in the direction perpendicular to the surface of the polishing pad, and the pressing force in the direction perpendicular to the surface of the polishing pad cannot be controlled. Therefore, clogging of the surface pores of the polishing pad cannot be sufficiently removed, and grinding is performed so that the surface of the polishing pad has a desired surface roughness for high-precision polishing of the semiconductor substrate. I can't.

  The conditioning unit contacts the surface of the polishing pad in a state where a pressing force in the vertical direction is applied, and swings while rotating to grind the surface of the polishing pad. Therefore, the conditioning unit is applied with force from the polishing pad surface from a plurality of directions such as a parallel direction as well as a vertical direction. However, in the conditioner disclosed in Patent Document 1, the conditioning unit is supported by a support unit having a space. Since it is supported, the conditioning part vibrates during grinding. Therefore, grinding cannot be performed so that the surface of the polishing pad has a desired surface roughness for high-precision polishing of the semiconductor substrate.

  Further, the conditioner disclosed in Patent Document 1 requires a mechanism for supplying a pressurized fluid to the space portion in order to control the pressing force in the direction perpendicular to the surface of the polishing pad, and thus has a complicated structure. End up.

  Therefore, an object of the present invention is to have a simple structure, avoiding deterioration of polishing performance due to clogging of the surface pores of the polishing pad and wear of the polishing pad surface, and the surface of the polishing pad highly accurately polishes the semiconductor substrate. It is to provide a conditioner that can be ground to have a desired surface roughness.

The present invention includes a conditioning unit that contacts and grinds the surface of the polishing pad;
A conditioner for a polishing pad, comprising a cushion layer having elasticity, and a support portion that supports the conditioning portion.

  Further, the present invention is characterized in that the conditioning unit is divided into a plurality of regions.

  According to the present invention, the conditioner has a conditioning part that contacts and grinds the surface of the polishing pad, and a support part that supports the conditioning part. And a support part is comprised including the cushion layer which has elasticity.

  In the conditioner configured as described above, the support portion configured to include the cushion layer supports the conditioning portion so as to be movable in a direction perpendicular to the polishing pad surface. Regardless, the pressing force in the direction perpendicular to the surface of the polishing pad can be controlled to be constant. And since the support part which supports a conditioning part is comprised so that a cushion layer may be provided without having a space part and the pressing force with respect to a polishing pad may be controlled, the abrasive grain contained in polishing liquid is a support part. Intrusion to the side can be prevented. Therefore, the conditioning unit supported by the support unit including the cushion layer can avoid a decrease in polishing performance due to clogging of the surface pores of the polishing pad or wear of the polishing pad surface, and polishing. The pad surface can be ground so as to have a desired surface roughness for high-precision polishing of the semiconductor substrate.

  In addition, when the conditioning unit comes into contact with the surface of the polishing pad in a state in which a pressing force in the vertical direction is applied, and swings while rotating to grind the surface of the polishing pad, the conditioning unit includes: Force is applied from the polishing pad surface not only in the vertical direction but also in a plurality of directions such as a parallel direction. On the other hand, since the conditioning part is supported by the support part comprised including a cushion layer, a cushion layer absorbs the vibration of a conditioning part during grinding. Therefore, grinding can be performed so that the surface of the polishing pad has a desired surface roughness for high-precision polishing of the semiconductor substrate. Further, the pressing force in the direction perpendicular to the surface of the polishing pad can be controlled with a simple configuration in which a cushion layer is provided on the support portion.

  According to the invention, the conditioning unit is divided into a plurality of regions. As a result, the pressing force in the direction perpendicular to the polishing pad surface can be controlled for each of the divided areas of the conditioning unit, so that the followability to the shape of the polishing pad surface is improved and more precise grinding is performed. Can do.

It is sectional drawing which shows the structure of the conditioner 10 which concerns on one Embodiment of this invention. It is sectional drawing which shows the example of the division | segmentation state of the conditioning part. 3 is a plan view illustrating an example of a division pattern of a conditioning unit 11. FIG. 3 is a plan view illustrating an example of a division pattern of a conditioning unit 11. FIG. It is a figure explaining the grinding operation of the conditioner. It is a figure which shows the structure of the conditioner unit 20 provided with the several conditioner 10. FIG.

  FIG. 1 is a cross-sectional view showing a configuration of a conditioner 10 according to an embodiment of the present invention. The conditioner 10 includes a conditioning unit 11 and a support unit 12, and in order to maintain and improve the surface performance of the polishing pad used for planarization polishing of a semiconductor substrate, the surface of the polishing pad is fixed by a certain amount. It is for grinding. The polishing pad to be ground by the conditioner 10 is not particularly limited, and is a known pad used for planarization polishing of a semiconductor substrate.

  The conditioning unit 11 is a part that contacts and grinds the surface of the polishing pad, and is a member that includes abrasive grains (such as diamond abrasive grains) that are commonly used for conditioners. Moreover, in this Embodiment, the conditioning part 11 is formed in disk shape as a whole.

  The support part 12 is a part which supports the conditioning part 11, and supports the conditioning part 11 by fixing methods, such as adhesion | attachment and electrodeposition. The support portion 12 has a three-layer structure including a cushion support layer 121, a cushion layer 122, and a conditioning portion contact layer 123. The conditioning part contact layer 123 is a layer provided so as to contact the conditioning part 11 on one surface in the thickness direction and to contact the cushion layer 122 on the other surface in the thickness direction, such as a metal material such as stainless steel (SUS), graphite, or the like. It is made of material.

  The cushion layer 122 is a layer provided so as to be in contact with the conditioning portion contact layer 123 on the one surface in the thickness direction and in contact with the cushion support layer 121 on the other surface in the thickness direction. ).

  The cushion support layer 121 is a layer provided to come into contact with the cushion layer 122 and adjust the overall thickness of the support portion 12, and is formed of the same material as the conditioning portion contact layer 123.

  Note that the support portion 12 may have a two-layer structure including the cushion layer 122 and the conditioning portion contact layer 123. Thus, when the support part 12 is comprised by 2 layer structure, the whole thickness of the support part 12 is adjusted by adjusting the layer thickness of the cushion layer 122 or the conditioning part contact layer 123. FIG.

  In the conditioner 10 configured as described above, when the surface of the polishing pad is ground, the conditioning unit 11 is brought into contact with the surface of the polishing pad with a predetermined pressing force. At this time, in the conditioner 10, the support portion 12 including the cushion layer 122 supports the conditioning portion 11 so as to be movable in a direction perpendicular to the polishing pad surface. Regardless of the shape, the pressing force in the direction perpendicular to the surface of the polishing pad can be controlled to be constant. And since the support part 12 which supports the conditioning part 11 is comprised so that the cushion layer 122 may be provided without having a space part, and the pressing force with respect to a polishing pad may be controlled, the abrasive grain contained in polishing liquid Can be prevented from entering the support portion 12 side. Therefore, the conditioning unit 11 supported by the support unit 12 including the cushion layer 122 can avoid a decrease in polishing performance due to clogging of the surface pores of the polishing pad or wear of the polishing pad surface. At the same time, the surface of the polishing pad can be ground so as to have a desired surface roughness for high-precision polishing of the semiconductor substrate.

  Further, when the conditioning unit 11 comes into contact with the surface of the polishing pad in a state where a pressing force in the vertical direction is applied, and swings while rotating to grind the surface of the polishing pad, the conditioning unit 11 is The force is applied from a plurality of directions such as a parallel direction as well as a vertical direction from the polishing pad surface. On the other hand, since the conditioning part 11 is supported by the support part 12 comprised including the cushion layer 122, the cushion layer 122 absorbs the vibration of the conditioning part 11 during grinding. Therefore, grinding can be performed so that the surface of the polishing pad has a desired surface roughness for high-precision polishing of the semiconductor substrate.

  Further, with a simple configuration in which the cushion layer 122 is provided on the support portion 12, the pressing force in the direction perpendicular to the polishing pad surface can be controlled, and the replacement work can be simplified and the cost can be reduced. Further, in the conditioner 10, since the entire region of the conditioning unit 11 is in contact with the polishing pad surface to perform grinding, it is possible to suppress only a specific region of the conditioning unit 11 from being excessively pressed against the polishing pad surface. The lifetime of 10 itself can be extended.

  In addition, the conditioning unit 11 can be divided into a plurality of regions. The division state of the conditioning unit 11 will be described with reference to FIG. FIG. 2 is a cross-sectional view illustrating an example of a division state of the conditioning unit 11.

  In the example of the division state of the conditioning unit 11 shown in FIG. 2A, only the conditioning unit 11 is divided into a plurality of region parts, that is, a first region part 11y and a second region part 11z. Yes. Thus, when the conditioning part 11 is divided | segmented into a some area | region, the groove part 30 is formed between the 1st area | region part 11y and the 2nd area | region part 11z.

  Further, in the example of the division state of the conditioning unit 11 shown in FIG. 2B, the support unit 12 corresponds to each region portion of the conditioning unit 11 divided into the first region portion 11y and the second region portion 11z. The conditioning part contact layer 123 is divided into a first contact layer 123y and a second contact layer 123z. Thus, when the conditioning part 11 and the conditioning part contact layer 123 are divided | segmented into a some area | region, the 1st area | region part 11y and the 1st contact layer 123y, the 2nd area | region part 11z, and the 2nd contact layer 123z Between the two, a groove 30 is formed.

  In the example of the division state of the conditioning unit 11 shown in FIG. 2C, the support unit 12 corresponds to each region portion of the conditioning unit 11 divided into the first region portion 11y and the second region portion 11z. The conditioning portion contact layer 123 is divided into a first contact layer 123y and a second contact layer 123z, and the cushion layer 122 is divided into a first cushion layer 122y and a second cushion layer 122z. Configured. Thus, when the conditioning part 11, the conditioning part contact layer 123, and the cushion layer 122 are divided into a plurality of regions, the first region part 11y, the first contact layer 123y, the first cushion layer 122y, and the second A groove 30 is formed between the region portion 11z, the second contact layer 123z, and the second cushion layer 122z.

  As described above, the conditioning unit 11 is divided into a plurality of regions, whereby the pressing force in the direction perpendicular to the polishing pad surface is controlled for each of the divided region portions 11y and 11z of the conditioning unit 11. Therefore, the followability with respect to the shape of the polishing pad surface is improved, and more precise grinding can be performed. Further, the groove 30 formed between the first region portion 11y and the second region portion 11z has a flow path through which a polishing liquid (slurry or pure water containing abrasive grains) used during grinding by the conditioner 10 flows. As a result, the conditioning action of the conditioner 10 is improved.

  Next, the division pattern in the conditioning unit 11 configured to be divided into a plurality of regions will be described. 3A and 3B are plan views showing examples of division patterns of the conditioning unit 11. In the conditioner 10, the conditioning unit 11 does not have to be divided as shown in FIG. 3A (a). However, as described above, the conditioning unit 11 is divided into a plurality of regions on a plane perpendicular to the central axis. It can also be done.

  As an example of the division pattern of the conditioning unit 11, for example, as shown in FIG. 3A (b), the disk-shaped conditioning unit 11 as a whole is concentric in the radial direction, that is, by virtual circles having different coaxial radii. The first region portion 11a and the second region portion 11b may be divided into two. At this time, an annular groove 30a is formed between the first region portion 11a and the second region portion 11b. Further, as shown in FIG. 3B (c), the disc-shaped conditioning portion 11 as a whole has the first region portion 11a and the second region portion 11b at equal intervals (center angle 90 °) in the circumferential direction with respect to the central axis. The third region portion 11c and the fourth region portion 11d may be divided into four, and the respective divided regions may have the same shape (sector shape). At this time, two groove portions 30b extending in the radial direction are formed between the region portions 11a to 11d. As shown in FIG. 3B (d), the disc-shaped conditioning portion 11 as a whole is divided into four at equal intervals (a central angle of 90 °) in the circumferential direction with respect to the central axis, and 2 concentrically in the radial direction. It divides | segments and you may be comprised so that it may divide into eight 1st-8th area | region parts (11a-11h) in total. At this time, an annular groove 30a is formed by concentric division between the region portions 11a to 11h, and two grooves 30b extending in the radial direction by being divided in the circumferential direction. It is formed.

  For example, FIG. 4 is a diagram illustrating the grinding operation of the conditioner 10. FIG. 4A is a perspective view showing the positional relationship between the conditioner 10 and the polishing pad 43 during grinding, and FIG. 4B shows the positional relationship between the conditioner 10 and the polishing pad 43 during grinding. FIG.

  First, the conditioner 10 is attached to the arm 40 of the polishing apparatus so that the conditioning unit 11 faces the polishing pad 43 attached to the polishing surface plate 44 of the polishing apparatus. The operation of the conditioner 10 is controlled by the control unit of the polishing apparatus.

  The control unit of the polishing apparatus stores in advance a plurality of programs (grinding recipes) corresponding to the polishing pad 43 to be ground and the polishing liquid (slurry or pure water containing abrasive grains) 42 used during grinding. Has been. And the control part of a polisher will control operation of conditioner 10 based on this grinding recipe, if one grinding recipe is chosen among a plurality of grinding recipes memorized beforehand.

  The control unit of the polishing apparatus controls the polishing liquid supply means (not shown) so that the polishing liquid 42 flows through the polishing liquid tube 41 and is affixed to the polishing surface plate 44 that is rotationally driven in the direction of arrow B. The surface of the polishing pad 43 is supplied. The control unit of the polishing apparatus swings in the arrow C direction while the conditioner 10 supported by the arm 40 contacts the surface of the polishing pad 43 with a predetermined pressing force and rotates in the arrow A direction. Then, the arm 40 is driven. The rotation direction in which the polishing surface plate 44 is rotationally driven, that is, the rotation direction B in which the polishing pad 43 is rotated and the rotation direction A in which the conditioner 10 rotates are the same direction.

  That is, the conditioner 10 swings in the direction of the arrow C while rotating in the direction of the arrow A, and the conditioning pad 11 is rotated in the direction of the arrow B under the intervention of the polishing liquid 42 with a predetermined pressing force. The surface of the polishing pad 43 is ground in contact with the surface of 43.

  Further, a plurality of conditioners 10 can be combined to form a single unit, and the surface of the polishing pad can be ground using the unit. FIG. 5 is a diagram illustrating a configuration of a conditioner unit 20 including a plurality of conditioners 10.

  The conditioner unit 20 is configured by attaching a plurality of conditioners 10 to a conditioner jig 21. Moreover, in the conditioner unit 20, each conditioning part 11 of each conditioner 10 is made to be on the same plane.

  Since the conditioner unit 20 includes a plurality of the conditioners 10 of the present embodiment, the surface of the polishing pad can be efficiently ground into a desired surface roughness and shape.

DESCRIPTION OF SYMBOLS 10 Conditioner 11 Conditioning part 12 Support part 121 Cushion support layer 122 Cushion layer 123 Conditioning part contact layer

Claims (2)

A conditioning unit that contacts and grinds the surface of the polishing pad;
A polishing pad conditioner comprising: a cushioning layer having elasticity, and a support part for supporting the conditioning part.   The conditioner for a polishing pad according to claim 1, wherein the conditioning unit is divided into a plurality of regions.

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