阅读说明：本技术 研磨垫修整方法
(Polishing pad dressing method
) 是由 唐强 于 2018-07-17 设计创作，主要内容包括：本发明涉及研磨垫修整方法,利用研磨垫修整器的修整盘对研磨垫进行修整,其中,在修整所述研磨区期间,沿所述研磨垫的中心朝向边缘的方向,所述修整盘施加在所述研磨区上的下压力逐渐降低,不同的下压力对研磨垫的修整程度不同,本发明的研磨垫修整方法可以改善现有CMP工艺中研磨垫经过一段时间的研磨过程之后均一性变差的问题,有利于研磨液均匀分布在研磨垫中的沟槽中,可以提高研磨去除率,延长研磨垫的使用寿命。(The invention relates to a method for dressing a grinding pad, which utilizes a dressing disk of a grinding pad dresser to dress the grinding pad, wherein during dressing the grinding area, along the direction from the center of the grinding pad to the edge, the downward pressure exerted on the grinding area by the dressing disk is gradually reduced, and the dressing degrees of the grinding pad by different downward pressures are different.)
1. A polishing pad dressing method characterized by dressing a polishing region of a polishing pad with a dressing disk of a polishing pad dresser, wherein a down-pressure applied to the polishing region by the dressing disk is gradually decreased in a direction from a center toward an edge of the polishing pad during dressing of the polishing region.
2. A method of conditioning a polishing pad as recited in claim 1, wherein the polishing region includes a first polishing region, a second polishing region, and a third polishing region connected in series in a direction from the center to the edge of the polishing pad, and conditioning the polishing region includes:
the conditioning disk undergoes a first reciprocating motion in the first polishing zone at a first lower pressure;
the conditioning disk undergoes a second reciprocating motion in the second grinding zone at a second lower pressure; and
said conditioning disk undergoing a third reciprocating motion at said third polishing zone at a third downforce;
wherein the first downforce is greater than the second downforce, and the second downforce is greater than the third downforce.
3. The method of claim 2, wherein the conditioning disk undergoes the first reciprocating motion, the second reciprocating motion, and the third reciprocating motion in sequence.
4. The method of claim 2, wherein the first downforce is in a range of 5.05psi to 5.15psi, the second downforce is in a range of 4.95psi to 5.05psi, and the third downforce is in a range of 4.85psi to 4.95 psi.
5. The method of claim 2, wherein the first reciprocating motion lasts for 2.8 seconds to 3.2 seconds, the second reciprocating motion lasts for 2.5 seconds to 2.8 seconds, and the third reciprocating motion lasts for 2.2 seconds to 2.5 seconds.
6. The method of claim 2, wherein the first polishing zone, the second polishing zone, and the third polishing zone have equal proportions in the polishing zones.
7. The method of any of claims 2 to 6, wherein the conditioning disk is driven by a rotating arm to perform the first reciprocating motion, the second reciprocating motion and the third reciprocating motion, and the rotating speed of the rotating arm is 45 to 55 rpm; and/or the grinding pad rotates by taking a normal line positioned at the center of the grinding pad as an axis, and the rotation rate of the grinding pad is 100-110 rpm.
8. The polishing pad conditioning method according to any one of claims 2 to 6, further comprising:
pre-conditioning said polishing zone prior to conditioning said polishing zone, during which pre-conditioning the downforce exerted by said conditioning disk on said polishing zone is at a constant value; and/or
After conditioning the polishing zone, performing a post-conditioning at the polishing zone during which a down-force exerted by the conditioning disk on the polishing pad is constant.
9. The method of claim 8, wherein the pre-conditioning duration is between 10 seconds and 12 seconds and the post-conditioning duration is between 8 seconds and 10 seconds.
10. A polishing pad conditioning method as recited in claim 8, further comprising:
after the post-conditioning of the polishing zone, performing a supplemental conditioning at the second polishing zone and the third polishing zone during which a down force exerted by the conditioning disk on the polishing pad is constant.
Technical Field
The invention relates to the field of semiconductor technology, in particular to a polishing pad dressing method.
Background
With the development of large scale integrated circuits, semiconductor devices are fabricated on the surface of a wafer in a high density cluster, and the wafer needs to be finely ground. Chemical Mechanical Polishing (CMP) is a polishing process for simultaneously performing mechanical polishing and chemical polishing on a wafer.
In a conventional CMP apparatus, a polishing pad (pad) on a polishing platen is provided to rotate together with the polishing platen, a wafer is sucked by a polishing head (polish head), then is brought into contact with the polishing pad and is pressurized, and is reciprocated and rotated in a predetermined region (for example, in a radial direction of the polishing pad), and the wafer is mechanically polished by friction, and further, a polishing liquid is supplied onto the polishing pad by a polishing liquid supply unit (slurry delivery), and the polishing pad dresser (pad conditioner) is reciprocated on the polishing pad by a conditioning disk (diamond disk) of a rotary arm (arm) so that the polishing liquid applied to the polishing pad is uniformly diffused on the polishing pad and flows into the wafer, and a certain pressure is applied to the polishing disk of the polishing pad dresser during the reciprocation, so that the polishing pad is mechanically conditioned (dressing) to maintain a certain polishing surface.
Generally, when the polishing pad is worn to a certain extent, the polishing pad has poor controllability of the polishing thickness of the wafer and the polishing quality is deteriorated, and it is necessary to replace the polishing pad. However, in the conventional CMP process, due to the inconsistent degree of wear of the surface of the polishing pad, the area of the polishing pad near the edge tends to be worn to a greater extent, while the area of the polishing pad near the center tends to be worn to a lesser extent, so that the uniformity of the polishing pad is deteriorated.
Disclosure of Invention
The invention mainly solves the technical problem that the grinding removal rate is reduced due to the fact that the surface uniformity of a grinding pad is poor in the existing CMP process.
In order to solve the above problems, the present invention provides a polishing pad dressing method characterized by dressing a polishing region of a polishing pad with a dressing disk of a polishing pad dresser, wherein a down force applied to the polishing region by the dressing disk is gradually reduced in a direction from a center of the polishing pad toward an edge during dressing of the polishing region.
Optionally, the polishing region includes a first polishing region, a second polishing region and a third polishing region sequentially connected in a direction from the center to the edge of the polishing pad, and the trimming the polishing region includes: the conditioning disk undergoes a first reciprocating motion in the first polishing zone at a first lower pressure; the conditioning disk undergoes a second reciprocating motion in the second grinding zone at a second lower pressure; and said conditioning disk undergoes a third reciprocating motion at a third downforce at said third polishing zone; wherein the first downforce is greater than the second downforce, and the second downforce is greater than the third downforce.
Optionally, the conditioning disk performs the first reciprocating motion, the second reciprocating motion, and the third reciprocating motion in sequence.
Optionally, the first downward pressure ranges from 5.05psi to 5.15psi, the second downward pressure ranges from 4.95psi to 5.05psi, and the third downward pressure ranges from 4.85psi to 4.95 psi.
Optionally, the duration time of the first reciprocating motion is 2.8 seconds to 3.2 seconds, the duration time of the second reciprocating motion is 2.5 seconds to 2.8 seconds, and the duration time of the third reciprocating motion is 2.2 seconds to 2.5 seconds.
Optionally, the percentage of the first polishing area, the second polishing area, and the third polishing area in the polishing area are all equal.
Optionally, the trimming disk is driven by a rotating arm to perform the first reciprocating motion, the second reciprocating motion and the third reciprocating motion, and the rotating rate of the rotating arm is 45-55 rpm; and/or the grinding pad rotates by taking a normal line positioned at the center of the grinding pad as an axis, and the rotation rate of the grinding pad is 100-110 rpm.
Optionally, the polishing pad dressing method further includes: pre-conditioning said polishing zone prior to conditioning said polishing zone, during which pre-conditioning the downforce exerted by said conditioning disk on said polishing zone is at a constant value; and/or after conditioning the polishing zone, performing a post-conditioning at the polishing zone during which a down-force exerted by the conditioning disk on the polishing pad is constant.
Optionally, the duration of the pre-trimming is 10 seconds to 12 seconds, and the duration of the post-trimming is 8 seconds to 10 seconds.
Optionally, the polishing pad dressing method further includes: after the post-conditioning of the polishing zone, performing a supplemental conditioning at the second polishing zone and the third polishing zone during which a down force exerted by the conditioning disk on the polishing pad is constant.
The inventor researches and discovers that the reason that the conventional polishing pad dressing method still cannot meet the requirement of the surface uniformity of the polishing pad is as follows: after a period of CMP process, the polishing pad is worn as a whole, but the wear degrees are different, wherein the wear degree of the region near the center of the polishing pad is smaller, the wear degree of the polishing pad gradually becomes worse along the direction from the center to the edge, and the wear degree is the largest in the region near the edge.
The invention provides a polishing pad dressing method, which utilizes a dressing disk of a polishing pad dresser to dress a polishing area of a polishing pad, wherein during dressing of the polishing area, the lower pressure exerted on the polishing area by the dressing disk is gradually reduced along the direction from the center of the polishing pad to the edge. Because the dressing degree of different lower pressure to the grinding pad is different, can improve the regional degree of wear that the grinding pad is close to the edge great and the degree of wear that is close to the regional degree of wear that leads to of central less in the grinding process after the grinding pad passes through a period of time among the current CMP technology, be favorable to the grinding fluid evenly distributed in the slot in the grinding pad, can improve and grind the clearance. In addition, the polishing pad dressing method of the invention is beneficial to improving the uniformity of the polishing pad and reducing the degree of edge abrasion of the polishing pad, thereby being beneficial to prolonging the service life of the polishing pad and reducing the replacement frequency of the polishing pad, thereby reducing the cost.
Drawings
FIG. 1 is a schematic view of a polishing pad and pad dresser.
FIG. 2a is a schematic cross-sectional view of a polishing pad without a CMP process.
FIG. 2b is a schematic cross-sectional view of the polishing pad after a certain period of CMP processing.
FIG. 3 is a schematic view of a polishing pad dresser and a polishing pad in accordance with an embodiment of the present invention.
FIG. 4 is a flowchart of a method for conditioning a polishing pad according to an embodiment of the invention.
FIG. 5 is a schematic cross-sectional view of a polishing pad after a period of CMP processing according to an embodiment of the invention.
Description of reference numerals:
20-a polishing pad; 21-a groove; 10-a wafer; 10 a-wafer rotation direction, 20 a-polishing pad rotation direction; 40 a-dresser disk rotation direction; 30-a supply unit; 40. 400-pad dresser; 41. 410-a rotating arm; 42. 420-trimming disk.
Detailed Description
The polishing pad conditioning method of the present invention is described in further detail below with reference to the accompanying drawings and specific examples. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are simplified in form and are not to precise scale for the purpose of facilitating and clearly illustrating the embodiments of the present invention, and that elements in some drawings may be the same as elements in other drawings, and although such elements may be easily identified in all drawings, the description will not mark all the same elements with the same reference numerals for clarity of the description of the drawings.
Chemical Mechanical Polishing (CMP) equipment is widely used in semiconductor device manufacturing processes, for example, to simultaneously perform mechanical polishing and chemical polishing on a wafer (wafer) surface in a semiconductor manufacturing process to obtain a flat surface. FIG. 1 is a schematic view of a polishing pad and pad dresser. Wherein, the polishing pad 20 is driven by the polishing platform to rotate at a certain speed along the polishing pad rotating direction 20a, the wafer 10 contacts with the polishing pad 20 and is pressurized, and simultaneously, the polishing pad 20 rotates along the wafer rotating direction 10a, the supply unit 30 supplies the polishing solution to the polishing pad 20 through the supply port, the surface of the polishing pad 20 contacts with the surface of the wafer 10 and moves relatively to perform mechanical and chemical polishing, thereby performing a polishing process of precisely planarizing the surface. Fig. 2a is a schematic cross-sectional view of a polishing pad without a CMP process (i.e., a new polishing pad). As shown in fig. 2a, a plurality of grooves 21 are formed in the polishing pad 20, and the grooves 21 are used to uniformly distribute the polishing slurry spread on the polishing pad 20 between the polishing pad 20 and the wafer 10. The thickness of the polishing pad 20 without being subjected to the CMP process is about 3 mm. After a certain period of time of the CMP process, the polishing pad 20 (usually made of polyurethane) is worn, the surface of the polishing pad 20 becomes smooth (glaze), and the polishing pad 20 is prone to accumulation of residual particles.
In order to ensure the quality of the CMP process, a polishing pad dresser (or conditioner) 40 is usually disposed on the CMP apparatus, and the polishing pad dresser 40 includes a rotating arm 41 and a dressing disk 42 driven by the rotating arm 41 to make a reciprocating motion on the polishing pad 20, wherein the reciprocating motion makes the polishing liquid spread uniformly on the polishing pad 20. In addition, the conditioning disk 42 typically includes diamond particles disposed on the bottom surface, and the reciprocating motion can scrape the surface of the polishing pad 20 to restore the polishing pad 20 to a proper roughness, so as to maintain the removal rate and stability of the wafer 10 by the polishing pad 20.
However, the inventors have found that, with the conventional polishing pad conditioning method, the polishing pad 20 has poor in-plane uniformity after a certain period of CMP process, and fig. 2b is a schematic cross-sectional view of the polishing pad after a certain period of CMP process. As shown in fig. 2b, after a certain period of CMP process, the polishing pad 20 is worn, but the degree of wear is different, wherein the wear degree of the region of the polishing pad 20 near the center O is smaller, the wear degree of the polishing pad 20 is gradually increased along the direction from the center O to the edge, and the wear degree is maximum in the region near the edge. Since the frictional force between the wafer 10 and the polishing pad 20 is related to the distance between the wafer 10 and the center point O of the polishing pad 20, when the wafer 10 is located at different positions along the radius of the polishing pad 20, the frictional force will cause different degrees of wear of the polishing pad 20, and the polishing pad dresser 40 performs uniform reciprocating motion on the polishing pad 20, so that the polishing pad 20 is dressed more uniformly, resulting in non-uniform degrees of wear of the polishing pad 20.
The in-plane non-uniformity of the polishing pad 20 is detrimental to the CMP process. On one hand, because the thicknesses of the central region and the edge region of the polishing pad 20 are not the same, the depths of the grooves 21 in different radii of the central point O are different, and especially, the depth of the grooves 21 in the edge region is smaller, so that the polishing liquid is less retained in the edge region, which may result in poor polishing effect; on the other hand, residual particles generated during the polishing process may also overflow the grooves 21 and may enter between the surface of the polishing pad 20 and the surface of the wafer 10, and these residual particles are prone to cause scratches (scratch) on the surface of the wafer 10 during the polishing process, thereby affecting the subsequent processes of the wafer 10; on the other hand, the thickness of the polishing pad 20 is usually gradually reduced after a certain period of CMP process, and when the thickness is reduced to a certain extent, it is necessary to replace the polishing pad 20 with a new one, for example, it can be set that the polishing pad 20 is replaced when the average thickness is reduced to 1.6mm, but the non-uniformity in the surface of the polishing pad 20 as shown in fig. 2b may cause the thickness in the central area to be still in a continuous use range, while the thickness in the edge area is smoothed (glazing), which may seriously affect the removal rate of the polishing pad 20 to the wafer 10 and the stability of the polishing process, and reduce the lifetime of the polishing pad 20, increasing the process cost. Therefore, the existing CMP process is desired to improve the in-plane non-uniformity of the polishing pad 20.
In view of the above problems, embodiments of the present invention improve the dressing method of a pad dresser to improve the in-plane uniformity of a polishing pad. The method for dressing a polishing pad according to this embodiment will be described below with reference to the drawings.
FIG. 3 is a schematic view of a polishing pad dresser and a polishing pad in accordance with an embodiment of the present invention. As shown in fig. 3, the polishing pad dresser 400 includes a rotating arm 410 and a dressing disk 420 connected to each other, the dressing disk 420 is in contact with the polishing pad 20 and dresses the polishing zone Z4 of the polishing pad 20 under the driving of the rotating arm 410, and the downward pressure applied to the polishing pad 20 by the dressing disk 420 is gradually reduced in a direction from the center of the polishing pad toward the edge during the dressing of the polishing zone Z4.
Further, the polishing zone Z4 of the conditioning disk 420 defined by the maximum rotation range (or span range, movement range) of the rotating arm 410 includes a first polishing zone Z1, a second polishing zone Z2 and a third polishing zone Z3 which are sequentially connected from the center O of the polishing pad 20 to the edge, in this embodiment, the maximum rotation angle of the rotating arm 410 is about 45 degrees, and the movement range of the corresponding conditioning disk 420 in the polishing zone Z4 may include the center O of the polishing pad 20 and the arc trajectory of the boundary.
FIG. 4 is a schematic flow chart illustrating a method for conditioning a polishing pad according to an embodiment of the invention. The polishing pad dressing method of the present embodiment will be described with reference to fig. 3 and 4.
After the wafer 10 is placed on the polishing pad 20, the supply unit 30 supplies the polishing liquid onto the polishing pad 20 through the supply port, and at this time, the polishing pad dresser 400 may be controlled to condition the polishing pad 20 by contacting the dressing disk 420 on the polishing pad 20.
In this embodiment, after the supply unit 30 supplies the polishing liquid onto the polishing pad 20, the trimming disk 420 may be driven by the rotating arm 410 to perform a pre-trimming in the polishing zone Z4 (i.e., the maximum range of the polishing zone) (i.e., step S1), and during the pre-trimming, the trimming disk 420 may reciprocate with the center O and the edge of the polishing pad 20 as two ends, so as to uniformly distribute the polishing liquid on the surface of the polishing pad 20, specifically, the process may uniformly distribute the polishing particles in the polishing liquid in the grooves 21 in the polishing pad 20, so that the surface of the wafer 10 is mechanically and chemically polished when contacting the surface of the polishing pad 20. It should be noted that the present embodiment focuses on the dressing method of the polishing pad dresser 400, and the polishing pad 20 itself can rotate at a fixed rotation speed (in the polishing pad rotation direction 20a) in the conventional manner, for example, the polishing pad 20 rotates around the normal line at the center O, and the rotation speed of the polishing pad 20 is, for example, 100 to 110 revolutions per minute (rpm/min). In another embodiment, during the process of the dressing disk 420 of the polishing pad dresser 400 dressing the polishing region of the polishing pad 20, the wafer 10 itself rotates in the direction opposite to the rotation direction of the polishing pad 20 (in the wafer rotation direction 10a), and the wafer 10 can move relative to the polishing pad 20 along the radius direction of the polishing pad 20.
In this embodiment, the conditioning disk 420 is rotated in the conditioning disk rotational direction 40a, and in addition, the conditioning disk 420 applies a constant downforce on the polishing pad 20 to perform pre-conditioning at the polishing zone Z4. The pre-trim downforce can be selected, for example, to be a constant value in the range of 4.85psi to 5.15psi, with the pre-trim duration being 10 to 12 seconds (sec).
In order to overcome the uneven wear of the polishing pad 20 caused by the friction between the wafer 10 and the polishing pad 20 due to the wafer 10 being located at different positions on the polishing pad during the polishing process of the wafer 10, the present embodiment uses the trimming disk 420 to trim different areas of the polishing zone Z4 of the polishing pad 20 with unequal down-pressure after pre-trimming.
Specifically, first, the conditioning disc 420 performs a first reciprocating motion at a first lower pressure in the first polishing zone Z1 (i.e., step S2), for example, the first reciprocating motion is performed with both ends of the first polishing zone Z1 as end points. The first polishing zone Z1 is preferably located closer to the center point O of the polishing pad 20, and the first polishing zone Z1 preferably covers the center point O, for example, the first lower pressure can be selected to be a constant value or a non-constant value in the range of 5.05psi to 5.15psi, and the distance that the conditioning disk 420 moves in the first polishing zone Z1 is about 1/5 to 1/3 of the radial length of the polishing pad 20 (e.g., the distance between the center point O and the edge of the polishing pad 20). The first reciprocating motion lasts for about 2.8 seconds to 3.2 seconds.
Next, the conditioning disk 420 performs a second reciprocating motion in the second polishing zone Z2 with a second downward pressure (i.e., step S3), for example, the second reciprocating motion is performed with both ends of the second polishing zone Z2 as end points. The second polishing zone Z2 is disposed between the center point O and the edge of the polishing pad 20 and connected to the first polishing zone Z1, and the distance of movement of the conditioning disk 420 in the second polishing zone Z2 is about 1/5 to 1/3 of the radial length of the polishing pad 20. The second reciprocating motion lasts for about 2.5 seconds to 2.8 seconds. For example, the second pressing force may be selected to be a constant value or a non-constant value in the range of 4.95psi to 5.05psi, and preferably, the value of the second pressing force is reduced from the value of the first pressing force.
Then, the conditioning disk 420 performs a third reciprocating motion with a third down force across the third polishing zone Z3 (i.e., step S4), for example, with both ends of the third polishing zone Z3 as end points. The third polishing zone Z3 is connected to the second polishing zone Z2, the distance of movement of the conditioning disk 420 in the third polishing zone Z3 may be 1/3, which is greater than or equal to the radial length of the polishing pad 20, and the third polishing zone Z3 may cover the edge of the polishing pad 20. The third reciprocating motion lasts for about 2.2 seconds to 2.5 seconds. For example, the third pressing force may be selected to be a constant value or a non-constant value in the range of 4.85psi to 4.95psi, and preferably, the value of the third pressing force is further reduced than the value of the second pressing force.
It should be noted that the specific values of the down-force, the moving time and the moving distance of the conditioning disk 420 in the polishing zone Z4, the first polishing zone Z1, the second polishing zone Z2 and the third polishing zone Z3 are only an example of the embodiments of the present invention, and the specific values of the down-force, the moving time and the moving distance may be different in different CMP apparatuses and different wafers.
In another embodiment of the present invention, the first polishing zone Z1, the second polishing zone Z2, and the third polishing zone Z3 may further include a smaller dressing range, that is, they may include one or more sub-polishing zones, and the polishing pad dressing method of the present embodiment may further include the reciprocating motion of the polishing pad dresser 40 in each sub-polishing zone, and the lower pressure applied to the polishing pad 20 by the dressing disk 420 may be gradually decreased in the reciprocating motion corresponding to the sub-polishing zones from the near to the far from the center point O.
It can be seen that the reciprocating motion of the conditioning disk 420 in the proximal and distal direction from the center point O during conditioning of the polishing zone Z4 with different downforce can be divided into three phases: the first reciprocating motion, the second reciprocating motion, and the third reciprocating motion, and the first lower pressure of the first reciprocating motion is largest near the center point O, the third lower pressure of the third reciprocating motion is smallest away from the center point O and covering the edge of the polishing pad 20, and the second lower pressure of the second reciprocating motion between the center point O and the boundary of the polishing pad 20 has a value between the first lower pressure and the third lower pressure. Therefore, the dressing method using the above-mentioned varying downward pressure can enhance the dressing force to the region near the center of the polishing pad 20 relative to the dressing method using the same downward pressure to the dressing disk, while the dressing force to the edge region of the polishing pad 20 is relatively reduced, i.e., the in-plane nonuniformity of the polishing pad 20 is adjusted by reducing the degree of wear of the edge region of the polishing pad 20 and increasing the degree of wear of the center region of the polishing pad 20, which is beneficial to obtain a polishing pad 20 surface with better uniformity, so that the polishing pad 20 maintains a uniform rough surface, and the depth of the grooves 21 on the polishing pad 20 is the same or close, so that the polishing particles in the polishing liquid can be uniformly distributed on the polishing pad 20, which is beneficial to improve the removal rate of the polishing pad 20 to the wafer 10 and the polishing stability.
Preferably, after the polishing zone Z4 is dressed with different downforce, the polishing pad dressing method of the present embodiment may further include a post-dressing (step S5) of the dressing disk 420 in the polishing zone Z4 (i.e., the maximum range of the polishing zone), in which the downforce applied to the dressing disk 420 is about 4.85psi to 5.15psi (a constant value within the range may be selected), so that the post-dressing can make the slurry uniformly distributed on the surface of the polishing pad 20, and the slurry can reach between the surface of the wafer 10 and the surface of the polishing pad 20 to increase the removal rate. The duration of the post-conditioning is about 8 seconds to about 10 seconds in this embodiment, and in some embodiments, the post-conditioning may continue until the end of the polishing process on the wafer 10 (or the wafer 10 is removed from the polishing pad 20).
Preferably, after the post-dressing, the polishing pad dressing method of the present embodiment may further include a supplementary dressing performed by the dressing disk 420 on the polishing pad 20 (i.e., step S6), and in some embodiments, the supplementary dressing may be performed after the wafer 10 is moved away from the polishing pad 20 while the polishing pad 20 is still rotating, and the purpose of the supplementary dressing is to remove residual particles on the polishing pad 20, such as polishing particles from the polishing slurry, by-products (by-products) generated from the thin film material removed by polishing on the surface of the wafer 10, and particles dropped from the polishing pad 20 or the polishing pad dresser 400, which may scratch the surface of the wafer during the subsequent polishing process, thereby reducing the residual particles on the polishing pad. Since the first downforce pressure in the first polishing zone Z1 is higher and the residual particles are less during the dressing process, the supplemental dressing, which includes, for example, the reciprocating motion with both ends at the end of the second polishing zone Z2 near the center O and at the end of the third polishing zone Z3 near the edge, can be performed in a concentrated manner in the second polishing zone Z2 and the third polishing zone Z3, and in the supplemental dressing, the downforce applied to the dressing disk 420 can be selected to be a constant value or a non-constant value in the range of 4.85psi to 5.15psi, and the duration of the supplemental dressing can be about 5 to 10 seconds.
The conditioning disk 420 of the present embodiment completes the conditioning process of the polishing pad 20 by the above-mentioned pre-conditioning, conditioning of the polishing region (including the first reciprocating motion, the second reciprocating motion, and the third reciprocating motion) at different down-pressures, post-conditioning, and supplementary conditioning. During the whole trimming process, the rotation rate of the trimming disk 420 and the rotation rate driven by the rotating arm 410 may be kept constant, the rotation rate of the trimming disk 420 is about 25 to 30 rpm, the trimming disk 420 is driven by the rotating arm 41 to perform the pre-trimming, the first reciprocating motion, the second reciprocating motion, the third reciprocating motion, the post-trimming and the supplemental trimming, and the rotation rate (i.e., the rotation rate of the reciprocating motion) of the rotating arm 410 is about 45 to 55 revolutions per minute (rpm/min).
The above description is only for the purpose of describing the preferred embodiments of the present invention and is not intended to limit the scope of the claims of the present invention, and any person skilled in the art can make possible the variations and modifications of the technical solutions of the present invention using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention, and therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention belong to the protection scope of the technical solutions of the present invention.
