CN114515994A - Method for improving grinding rate of edge area of wafer - Google Patents
Method for improving grinding rate of edge area of wafer Download PDFInfo
- Publication number
- CN114515994A CN114515994A CN202210203428.0A CN202210203428A CN114515994A CN 114515994 A CN114515994 A CN 114515994A CN 202210203428 A CN202210203428 A CN 202210203428A CN 114515994 A CN114515994 A CN 114515994A
- Authority
- CN
- China
- Prior art keywords
- wafer
- grinding
- layer structure
- polishing
- pad
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B37/00—Lapping machines or devices; Accessories
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
- B24B1/00—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
Abstract
The invention provides a method for improving the grinding rate of a wafer edge area, which comprises the following steps: the method comprises the following steps of grinding a wafer by adopting chemical mechanical grinding equipment, wherein a grinding pad in the chemical mechanical grinding equipment is of a double-layer structure, the upper layer structure of the grinding pad is in contact with the surface of the wafer, the wafer is surrounded and fixed by a retaining ring, and the edge area of the wafer is in contact with both the grinding pad and the retaining ring; the hardness of the upper layer structure of the grinding pad is higher than that of the lower layer structure of the grinding pad, so that the hardness of the lower layer structure of the grinding pad is improved, and the grinding rate of the edge area of the wafer is improved. According to the invention, the hardness of the grinding pad is adjusted, especially the hardness of the lower layer structure of the grinding pad is improved, so that the micro deformation of the contact areas of the wafer edge, the grinding pad and the retaining ring is reduced during grinding, and the mechanical force of interaction is enhanced, thereby improving the grinding rate of the wafer edge, solving the problem of residue retention and improving the yield; the method is simple to operate, high in flexibility, low in cost and wide in application range.
Description
Technical Field
The invention belongs to the technical field of chemical mechanical polishing, and relates to a method for improving the polishing rate of a wafer edge area.
Background
Chemical mechanical polishing is a mainstream surface planarization method in the field of semiconductor manufacturing, which can be referred to as chemical mechanical polishing, and is very important for controlling the uniformity of the surface thickness of a wafer, and the in-plane uniformity and the local planarization degree of the film thickness are important indexes for controlling and evaluating the chemical mechanical polishing process. During chemical mechanical polishing, the polishing head clamps the wafer, the outer side of the wafer is also provided with a retaining ring, and the polishing head presses the wafer onto the polishing pad, so that the structure of the chemical mechanical polishing equipment can influence the surface uniformity and the planarization degree of the wafer after the chemical mechanical polishing except the surface condition of the wafer.
The grinding pad is used as a carrier of the wafer, is in direct contact with the surface of the wafer, removes a certain amount of film on the surface of the wafer through the combined action of pressure and shearing force to achieve the effect of planarization, and according to the difference between the central area and the edge of the wafer and the position relation of each structural component, the grinding rate of the edge of the wafer in the prior art is usually low, namely the removal amount of the edge of the wafer is less, residues are easy to exist, and therefore the yield is influenced. At present, the improvement of the wafer edge grinding rate is mainly to adjust the pressure applied by a machine table to a retaining ring, but the adjustment space of the parameter is limited, and the abrasion of a grinding pad and the retaining ring is easily caused by overlarge pressure, so the service life of the grinding pad and the retaining ring is shortened.
CN 113510609a discloses a method for processing a wafer, which includes: providing a wafer to be ground, wherein the wafer to be ground comprises a central area and an edge area; fixing a wafer to be ground on a clamp to enable the wafer to be bent, wherein the central area of the wafer is bent towards the clamp; placing the bent wafer on a grinding pad, and grinding and removing the surface part of the edge area of the wafer by using grinding liquid; adjusting the arrangement of the clamp to enable the wafer to be straight; the central region of the wafer is polished by a polishing pad. The method is characterized in that the edge area of the wafer is pre-ground, impurities in the edge area are removed, the wafer is prevented from being scratched by the falling of the impurities, the improvement of the grinding rate of the edge area is not emphasized, the requirement of the clamp for bending the wafer on the wafer is high, the wafer is easy to damage, and the operation difficulty is high.
CN 101121245a discloses a method for improving CMP uniformity of oxide film, comprising: in the first stage of main grinding, grinding the surface of the wafer by using a high-hardness grinding pad to eliminate the step difference; in the second stage of main grinding, grinding the surface of the ground wafer by using a medium-hardness grinding pad; this method improves the in-plane uniformity by performing multi-stage polishing on a wafer, has many operation steps, requires many kinds of polishing pads, does not involve the use of a retainer ring, and does not clearly improve polishing of the edge region of the wafer.
In summary, for the improvement of the polishing rate of the wafer edge region in the chemical mechanical polishing process, it is necessary to improve the polishing effect of the edge region and solve the problem of the residue on the wafer edge from new aspects, such as the characteristics of the polishing pad.
Disclosure of Invention
In view of the problems in the prior art, an object of the present invention is to provide a method for increasing the polishing rate of the edge region of a wafer, which reduces the micro-deformation of the wafer edge, the polishing pad and the contact region of a retaining ring during polishing and enhances the mechanical force of interaction by adjusting the hardness of the polishing pad during chemical mechanical polishing, especially increasing the hardness of the underlying structure of the polishing pad, thereby increasing the polishing rate of the edge region of the wafer, solving the problem of residue retention, and increasing the production yield of the wafer.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a method for improving the grinding rate of a wafer edge area, which comprises the following steps:
the method comprises the following steps of grinding a wafer by adopting chemical mechanical grinding equipment, wherein a grinding pad in the chemical mechanical grinding equipment is of a double-layer structure, the upper layer structure of the grinding pad is in contact with the surface of the wafer, the wafer is surrounded and fixed by a retaining ring, and the edge area of the wafer is in contact with both the grinding pad and the retaining ring;
The hardness of the upper layer structure of the grinding pad is higher than that of the lower layer structure of the grinding pad, so that the hardness of the lower layer structure of the grinding pad is improved, and the grinding rate of the edge area of the wafer is improved.
In the invention, chemical mechanical polishing is used as an important operation for wafer surface planarization, the polishing uniformity of each part of the surface needs to be ensured, but according to the structural characteristics of the wafer and the polishing equipment, the polishing degree of the edge area of the wafer is often lower than that of the central area, so that the polishing rate of the edge of the wafer needs to be improved; the invention improves the grinding degree of the edge of the wafer by changing the physical parameters of the grinding pad, particularly the hardness of the lower layer structure of the grinding pad, which is mainly based on the position relation of the wafer, the grinding pad and the retaining ring during the chemical mechanical grinding, and can cause certain deformation in the edge area of the wafer due to the mechanical force of the interaction among the three, so that the hardness of the grinding pad can be enhanced to reduce the deformation, thereby being beneficial to the close contact between the edge of the wafer and the grinding pad, improving the grinding rate, avoiding the problem of residue retention on the wafer, ensuring the cleanness of the polished surface and improving the yield of the wafer production;
compared with the traditional mode of applying pressure by improving the retaining ring and the grinding head, the mode of the invention has stronger flexibility, the problem of limited adjusting space of the retaining ring and the grinding head is avoided, only the hardness of the lower layer structure is adjusted mainly in the double-layer structure of the grinding pad, the hardness of the lower layer structure is lower, the buffering effect is mainly achieved, the hardness of the upper layer structure is relatively higher, the main grinding rate is contributed, if the hardness of the upper layer structure is adjusted, the whole grinding process of the wafer can be directly influenced, the proper grinding rate of the central area of the wafer cannot be ensured, therefore, the hardness of the lower layer structure is adjusted indirectly, and the grinding rate of the edge of the wafer is improved under the condition of basically not influencing the grinding rate of the center of the wafer; the method is simple to operate, obvious in improvement effect, low in cost and wide in application range.
The following technical solutions are preferred technical solutions of the present invention, but not limited to the technical solutions provided by the present invention, and technical objects and advantageous effects of the present invention can be better achieved and achieved by the following technical solutions.
As a preferred technical solution of the present invention, the chemical mechanical polishing apparatus sequentially includes, from top to bottom, a polishing head, a polishing pad, and a polishing table, the retaining ring is a structural component of the polishing head, and the wafer is located between the polishing head and the polishing pad.
Preferably, during the chemical mechanical polishing, the polishing head drives the wafer to rotate, and the polishing table drives the polishing pad to rotate.
Preferably, the rotation directions of the wafer and the grinding pad are the same, and the rotation speeds are different.
In a preferred embodiment of the present invention, the material of the upper layer structure of the polishing pad includes polyurethane.
Preferably, the hardness of the upper layer structure of the polishing pad is 58 to 68SHD, such as 58SHD, 60SHD, 62SHD, 64SHD, 66SHD, or 68SHD, but is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.
In the invention, SHD and SHA are indexes for representing the hardness of the high polymer material, probes used by the SHD and SHA are different, the SHA is generally used for representing a softer material, and the SHD is used for representing after a certain hardness is reached, so that the data is more accurate.
In a preferred embodiment of the present invention, the material of the lower layer structure of the polishing pad includes a nonwoven fabric.
Preferably, the non-woven fabric comprises any one of polypropylene non-woven fabric, polyurethane non-woven fabric or polyester non-woven fabric or a combination of at least two of the following, typical but non-limiting examples being: a combination of polypropylene nonwoven fabric and polyurethane nonwoven fabric, a combination of polyurethane nonwoven fabric and polyester nonwoven fabric, a combination of polypropylene nonwoven fabric, polyurethane nonwoven fabric and polyester nonwoven fabric, and the like.
Preferably, the hardness of the underlying structure of the polishing pad is 71 to 89SHA, for example, 71SHA, 73SHA, 75SHA, 78SHA, 80SHA, 83SHA, 85SHA, or 89SHA, but is not limited to the recited values, and other values not recited in the range of values are also applicable.
In the present invention, the material selection and hardness of the polishing pad are determined by the function of the lower layer structure, so that the hardness of the upper layer is higher than that of the lower layer, i.e., the hardness of the lower layer structure is adjusted.
In a preferred embodiment of the present invention, the thickness of the upper layer structure of the polishing pad is 1.0 to 2.0mm, for example, 1.0mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, or 2.0mm, but the thickness is not limited to the above-mentioned values, and other values not listed in the above-mentioned value range are also applicable.
Preferably, the thickness of the underlying structure of the polishing pad is 0.5 to 1.0mm, for example 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, or 1.0mm, but is not limited to the recited values, and other values not recited within this range are also applicable.
Preferably, the upper layer structure and the lower layer structure of the polishing pad are both microporous structures, the diameter of the micropores of the upper layer structure is 12 to 17 μm, such as 12 μm, 13 μm, 14 μm, 15 μm, 16 μm or 17 μm, and the diameter of the micropores of the lower layer structure is 18 to 22 μm, such as 18 μm, 19 μm, 20 μm, 21 μm or 22 μm, but the invention is not limited to the recited values, and other values not recited in the respective numerical ranges are also applicable.
In a preferred embodiment of the present invention, the upper layer structure and the lower layer structure of the polishing pad are bonded to each other by an adhesive layer.
Preferably, the adhesive layer is formed by melting an acrylic adhesive and then cooling and solidifying.
In the present invention, the adhesive layer is usually formed by curing an adhesive, and a polymer organic material is usually selected as the adhesive according to need, and is easily melted and has a high viscosity.
As a preferable technical scheme of the invention, the material is unchanged before and after the lower layer structure of the grinding pad is improved, and the microstructure is adjusted from an open pore structure to a closed pore structure.
Preferably, the hardness of the polishing pad underlayer is improved by 4 to 10%, for example, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, but the hardness is not limited to the above-mentioned values, and other values not listed in the above-mentioned range are also applicable.
In the chemical mechanical polishing according to a preferred embodiment of the present invention, the pressure applied to the wafer by the polishing head is 4 to 6psi, for example, 4psi, 4.5psi, 5psi, 5.5psi, or 6psi, and the pressure applied to the retaining ring is 6 to 8psi, for example, 6psi, 6.5psi, 7psi, 7.5psi, or 8psi, but the invention is not limited to the above values, and other values not listed in the range of the respective values are also applicable.
Preferably, the rotation speed of the wafer during the chemical mechanical polishing is 85 to 90r/min, such as 85r/min, 86r/min, 87r/min, 88r/min, 89r/min or 90r/min, but not limited to the values listed, and other values not listed in the range of the values are also applicable; the rotational speed of the polishing pad is 90 to 95r/min, such as 90r/min, 91r/min, 92r/min, 93r/min, 94r/min or 95r/min, but is not limited to the values listed, and other values not listed within this range are also applicable.
As a preferable technical scheme of the invention, the chemical mechanical polishing removes impurities and oxides on the surface of the wafer.
Preferably, the oxide on the surface of the wafer comprises tetraethoxysilane.
As a preferred technical scheme of the invention, the method comprises the following steps:
the wafer is ground by adopting chemical mechanical grinding equipment, the chemical mechanical grinding equipment sequentially comprises a grinding head, a grinding pad and a grinding table from top to bottom, the retaining ring is a structural component of the grinding head, and the wafer is positioned between the grinding head and the grinding pad; the polishing pad in the chemical mechanical polishing device is of a double-layer structure, the upper layer structure of the polishing pad is in contact with the surface of a wafer, the wafer is surrounded and fixed by a retaining ring, and the edge area of the wafer is in contact with both the polishing pad and the retaining ring;
the upper layer structure of the grinding pad is made of polyurethane, the hardness is 58-68 SHD, the thickness is 1.0-2.0 mm, and the diameter of each micropore is 12-17 mu m; the lower layer structure of the polishing pad is made of non-woven fabrics, the hardness is 71-89 SHA, the thickness is 0.5-1.0 mm, and the diameter of each micropore is 18-22 mu m; the upper layer structure and the lower layer structure are combined through a bonding layer; the hardness of the lower layer structure of the grinding pad is higher than that of the lower layer structure of the grinding pad by 4-10% on the premise of improvement so as to improve the grinding rate of the edge area of the wafer;
During the chemical mechanical polishing, the pressure applied to the wafer by the polishing head is 4-6 psi, the pressure applied to the retaining ring is 6-8 psi, the rotation speed of the wafer is 85-90 r/min, the rotation speed of the polishing pad is 90-95 r/min, the rotation directions of the wafer and the polishing pad are the same, and impurities and oxides on the surface of the wafer are removed through the chemical mechanical polishing, so that the surface of the wafer is cleaned.
Compared with the prior art, the invention has the following beneficial effects:
(1) according to the method, the hardness of the grinding pad during chemical mechanical grinding is adjusted, and particularly the hardness of the lower layer structure of the grinding pad is improved, so that the micro deformation of the wafer edge, the grinding pad and the contact area of the retaining ring is reduced during grinding, the mechanical force of interaction is enhanced, the grinding rate of the wafer edge area is improved, the problem of residue retention is solved, and the yield of wafer production can reach more than 95%;
(2) the method disclosed by the invention is simple to operate, strong in flexibility, lower in cost and wide in application range.
Drawings
FIG. 1 is a graph illustrating the polishing rate after the first polishing of the wafer surfaces provided in example 1 and comparative example 1 of the present invention;
fig. 2 is a graph illustrating the polishing rate after the second polishing of the wafer surface according to example 1 and comparative example 1 of the present invention.
Detailed Description
In order to better explain the present invention and to facilitate the understanding of the technical solutions of the present invention, the present invention is further described in detail below. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of the present invention, which is defined by the claims.
The embodiments of the present invention provide, in part, a method for increasing a grinding rate of an edge region of a wafer, the method comprising:
the method comprises the following steps of grinding a wafer by adopting chemical mechanical grinding equipment, wherein a grinding pad in the chemical mechanical grinding equipment is of a double-layer structure, the upper layer structure of the grinding pad is in contact with the surface of the wafer, the wafer is surrounded and fixed by a retaining ring, and the edge area of the wafer is in contact with both the grinding pad and the retaining ring;
the hardness of the upper layer structure of the grinding pad is higher than that of the lower layer structure of the grinding pad, so that the hardness of the lower layer structure of the grinding pad is improved.
The following are typical but non-limiting examples of the invention:
example 1:
the embodiment provides a method for improving the grinding rate of a wafer edge area, which comprises the following steps:
the method comprises the following steps of grinding a wafer by adopting chemical mechanical grinding equipment, wherein the chemical mechanical grinding equipment sequentially comprises a grinding head, a grinding pad and a grinding table from top to bottom, a retaining ring is a structural component of the grinding head, and the wafer is positioned between the grinding head and the grinding pad; the polishing pad in the chemical mechanical polishing equipment is of a double-layer structure, the upper layer structure of the polishing pad is in contact with the surface of a wafer, the wafer is surrounded and fixed by a retaining ring, and the edge area of the wafer is in contact with both the polishing pad and the retaining ring;
The upper layer structure of the grinding pad is made of polyurethane, the hardness is 60SHD, the thickness is 1.6mm, and the average micropore diameter is 15 micrometers; the lower layer structure of the grinding pad is made of polypropylene non-woven fabric, the hardness is 87SHA, the thickness is 0.8mm, and the average micropore diameter is 20 micrometers; the upper layer structure and the lower layer structure are combined through a bonding layer, and the bonding layer is formed by melting an acrylic adhesive and then cooling and solidifying the acrylic adhesive; the hardness of the lower layer structure of the grinding pad is 10.0% higher than that of the lower layer structure of the grinding pad on the premise of improvement so as to improve the grinding rate of the edge area of the wafer;
during the chemical mechanical polishing, the pressure applied to the wafer by the polishing head is 4.9psi, the pressure applied to the retaining ring is 7.2psi, the rotating speed of the wafer is 87r/min, the rotating speed of the polishing pad is 93r/min, the rotating directions of the wafer and the polishing pad are the same, impurities and tetraethoxysilane oxide on the surface of the wafer are removed through the chemical mechanical polishing, and the surface of the wafer is cleaned.
Example 2:
the embodiment provides a method for improving the grinding rate of a wafer edge area, which comprises the following steps:
the wafer is ground by adopting chemical mechanical grinding equipment, the chemical mechanical grinding equipment sequentially comprises a grinding head, a grinding pad and a grinding table from top to bottom, the retaining ring is a structural component of the grinding head, and the wafer is positioned between the grinding head and the grinding pad; the polishing pad in the chemical mechanical polishing equipment is of a double-layer structure, the upper layer structure of the polishing pad is in contact with the surface of a wafer, the wafer is surrounded and fixed by a retaining ring, and the edge area of the wafer is in contact with both the polishing pad and the retaining ring;
The upper layer structure of the grinding pad is made of polyurethane, the hardness is 68SHD, the thickness is 1.0mm, and the average micropore diameter is 12 micrometers; the lower layer structure of the grinding pad is made of polypropylene non-woven fabric, the hardness is 80SHA, the thickness is 0.5mm, and the average micropore diameter is 18 mu m; the upper layer structure and the lower layer structure are combined through a bonding layer, and the bonding layer is formed by melting an acrylic adhesive and then cooling and solidifying the acrylic adhesive; the hardness of the lower layer structure of the grinding pad is 6% higher than that of the lower layer structure of the grinding pad on the premise of improvement so as to improve the grinding rate of the edge area of the wafer;
during the chemical mechanical polishing, the pressure applied to the wafer by the polishing head is 4psi, the pressure applied to the retaining ring is 6psi, the rotating speed of the wafer is 85r/min, the rotating speed of the polishing pad is 90r/min, the rotating directions of the wafer and the polishing pad are the same, impurities and ethyl orthosilicate oxide on the surface of the wafer are removed through chemical mechanical polishing, and the surface of the wafer is cleaned.
Example 3:
the embodiment provides a method for improving the grinding rate of a wafer edge area, which comprises the following steps:
the wafer is ground by adopting chemical mechanical grinding equipment, the chemical mechanical grinding equipment sequentially comprises a grinding head, a grinding pad and a grinding table from top to bottom, the retaining ring is a structural component of the grinding head, and the wafer is positioned between the grinding head and the grinding pad; the polishing pad in the chemical mechanical polishing equipment is of a double-layer structure, the upper layer structure of the polishing pad is in contact with the surface of a wafer, the wafer is surrounded and fixed by a retaining ring, and the edge area of the wafer is in contact with both the polishing pad and the retaining ring;
The upper layer structure of the grinding pad is made of polyurethane, the hardness is 58SHD, the thickness is 2.0mm, and the average micropore diameter is 17 micrometers; the lower layer structure of the grinding pad is made of polyester non-woven fabric, the hardness is 72SHA, the thickness is 1.0mm, and the average micropore diameter is 22 mu m; the upper layer structure and the lower layer structure are combined through a bonding layer, and the bonding layer is formed by melting an acrylic adhesive and then cooling and solidifying the acrylic adhesive; the hardness of the lower layer structure of the grinding pad is higher than that of the lower layer structure of the grinding pad by 4 percent on the premise of improvement so as to improve the grinding rate of the edge area of the wafer;
during the chemical mechanical polishing, the pressure applied to the wafer by the polishing head is 6psi, the pressure applied to the retaining ring is 8psi, the rotating speed of the wafer is 90r/min, the rotating speed of the polishing pad is 95r/min, the rotating directions of the wafer and the polishing pad are the same, impurities and ethyl orthosilicate oxide on the surface of the wafer are removed through chemical mechanical polishing, and the surface of the wafer is cleaned.
Example 4:
the embodiment provides a method for improving the grinding rate of a wafer edge area, which comprises the following steps:
the wafer is ground by adopting chemical mechanical grinding equipment, the chemical mechanical grinding equipment sequentially comprises a grinding head, a grinding pad and a grinding table from top to bottom, the retaining ring is a structural component of the grinding head, and the wafer is positioned between the grinding head and the grinding pad; the polishing pad in the chemical mechanical polishing equipment is of a double-layer structure, the upper layer structure of the polishing pad is in contact with the surface of a wafer, the wafer is surrounded and fixed by a retaining ring, and the edge area of the wafer is in contact with both the polishing pad and the retaining ring;
The upper layer structure of the grinding pad is made of polyurethane, the hardness is 63SHD, the thickness is 1.5mm, and the average micropore diameter is 13 mu m; the lower layer structure of the grinding pad is made of polypropylene non-woven fabric, the hardness is 75SHA, the thickness is 0.6mm, and the average micropore diameter is 21 mu m; the upper layer structure and the lower layer structure are combined through a bonding layer, and the bonding layer is formed by melting an acrylic adhesive and then cooling and solidifying the acrylic adhesive; the hardness of the lower layer structure of the grinding pad is 5% higher than that of the lower layer structure of the grinding pad on the premise of improvement so as to improve the grinding rate of the edge area of the wafer;
during the chemical mechanical polishing, the pressure applied to the wafer by the polishing head is 4.5psi, the pressure applied to the retaining ring is 6.6psi, the rotating speed of the wafer is 86r/min, the rotating speed of the polishing pad is 94r/min, the rotating directions of the wafer and the polishing pad are the same, impurities and tetraethoxysilane oxide on the surface of the wafer are removed through the chemical mechanical polishing, and the surface of the wafer is cleaned.
Example 5:
the embodiment provides a method for improving the grinding rate of a wafer edge area, which comprises the following steps:
the wafer is ground by adopting chemical mechanical grinding equipment, the chemical mechanical grinding equipment sequentially comprises a grinding head, a grinding pad and a grinding table from top to bottom, the retaining ring is a structural component of the grinding head, and the wafer is positioned between the grinding head and the grinding pad; the polishing pad in the chemical mechanical polishing equipment is of a double-layer structure, the upper layer structure of the polishing pad is in contact with the surface of a wafer, the wafer is surrounded and fixed by a retaining ring, and the edge area of the wafer is in contact with both the polishing pad and the retaining ring;
The upper layer structure of the grinding pad is made of polyurethane, the hardness is 65SHD, the thickness is 1.2mm, and the average micropore diameter is 16 microns; the lower layer structure of the grinding pad is made of polyurethane non-woven fabric, the hardness is 85SHA, the thickness is 0.7mm, and the average micropore diameter is 19 mu m; the upper layer structure and the lower layer structure are combined through a bonding layer, and the bonding layer is formed by melting an acrylic adhesive and then cooling and solidifying the acrylic adhesive; the hardness of the lower layer structure of the grinding pad is 8% higher than that of the lower layer structure of the grinding pad on the premise of improvement so as to improve the grinding rate of the edge area of the wafer;
during the chemical mechanical polishing, the pressure applied to the wafer by the polishing head is 5.4psi, the pressure applied to the retaining ring is 7.5psi, the rotating speed of the wafer is 88r/min, the rotating speed of the polishing pad is 92r/min, the rotating directions of the wafer and the polishing pad are the same, impurities and tetraethoxysilane oxide on the surface of the wafer are removed through the chemical mechanical polishing, and the surface of the wafer is cleaned.
Comparative example 1:
this comparative example provides a method of increasing the grinding rate of the edge area of a wafer, which is comparable to the method of example 1, except that: the hardness of the underlying structure of the polishing pad was not adjusted, and was 79 SHA.
The wafers in example 1 and comparative example 1 were polished twice under the same conditions, and the polishing rates of the surfaces after the first polishing and the second polishing were measured, and the polishing rates of the points on a certain diameter were taken as an example, and the graphs connecting the points are shown in fig. 1 and fig. 2, respectively.
As can be seen from fig. 1 and 2, when the wafer is polished after the improvement in example 1, the polishing rate of the edge area of the wafer is significantly higher than that of the wafer before the improvement in comparative example 1, the improvement rate is about 3%, and the polishing rate of the center area is not substantially affected, so that the problem of residue existing at the edge of the wafer due to the low polishing rate can be effectively solved.
It can be seen from the above embodiments and comparative examples that the method of the present invention adjusts the hardness of the polishing pad during chemical mechanical polishing, especially improves the hardness of the underlying structure of the polishing pad, so that the microscopic deformation of the wafer edge, the polishing pad and the contact region of the retaining ring during polishing is reduced, the mechanical force of interaction is enhanced, thereby improving the polishing rate of the wafer edge region, solving the problem of residue retention, and the yield of wafer production can reach more than 95%; the method is simple to operate, high in flexibility, low in cost and wide in application range.
The present invention is illustrated in detail by the examples given above, but the present invention is not limited to the details given above, which means that the present invention is not limited to the details given above. It will be apparent to those skilled in the art that any modifications to the present invention, equivalents of the method of the present invention and additions of ancillary steps, selection of specific means, etc., are within the scope and disclosure of the present invention.
Claims (10)
1. A method for increasing the polishing rate of an edge region of a wafer, the method comprising the steps of:
the method comprises the following steps of grinding a wafer by adopting chemical mechanical grinding equipment, wherein a grinding pad in the chemical mechanical grinding equipment is of a double-layer structure, the upper layer structure of the grinding pad is in contact with the surface of the wafer, the wafer is surrounded and fixed by a retaining ring, and the edge area of the wafer is in contact with both the grinding pad and the retaining ring;
the hardness of the upper layer structure of the grinding pad is higher than that of the lower layer structure of the grinding pad, and meanwhile, the hardness of the lower layer structure of the grinding pad is improved.
2. The method of claim 1, wherein the chemical mechanical polishing apparatus comprises, from top to bottom, a polishing head, a polishing pad, and a polishing table, the retaining ring is a structural component of the polishing head, and the wafer is located between the polishing head and the polishing pad;
Preferably, during the chemical mechanical polishing, the polishing head drives the wafer to rotate, and the polishing table drives the polishing pad to rotate;
preferably, the rotation directions of the wafer and the grinding pad are the same, and the rotation speeds are different.
3. The method of claim 1 or 2, wherein the material of the upper layer structure of the polishing pad comprises polyurethane;
preferably, the hardness of the upper layer structure of the polishing pad is 58-68 SHD.
4. The method according to any one of claims 1-3, wherein the material of the lower layer of the polishing pad comprises a non-woven fabric;
preferably, the non-woven fabric comprises any one of polypropylene non-woven fabric, polyurethane non-woven fabric or polyester non-woven fabric or a combination of at least two of the polypropylene non-woven fabric, the polyurethane non-woven fabric and the polyester non-woven fabric;
preferably, the hardness of the lower layer structure of the polishing pad is 71 to 89 SHA.
5. The method according to any one of claims 1 to 4, wherein the thickness of the upper layer structure of the polishing pad is 1.0 to 2.0 mm;
preferably, the thickness of the lower layer structure of the grinding pad is 0.5-1.0 mm;
preferably, the upper layer structure and the lower layer structure of the grinding pad are both microporous structures, the diameter of micropores of the upper layer structure is 12-17 μm, and the diameter of micropores of the lower layer structure is 18-22 μm.
6. The method of any of claims 1-5, wherein the upper layer and the lower layer of the polishing pad are bonded by a bonding layer;
preferably, the adhesive layer is formed by melting an acrylic adhesive and then cooling and solidifying.
7. The method of any of claims 1-6, wherein the material is unchanged before and after the improvement of the polishing pad substructure, and the microstructure is modified from an open-cell structure to a closed-cell structure;
preferably, after the material of the lower layer structure of the polishing pad is improved, the hardness of the lower layer structure is improved by 4-10%.
8. The method according to any one of claims 2 to 7, wherein the pressure applied by the polishing head to the wafer is 4 to 6psi and the pressure applied by the polishing head to the retaining ring is 6 to 8psi during the chemical mechanical polishing;
preferably, during the chemical mechanical polishing, the rotation speed of the wafer is 85 to 90r/min, and the rotation speed of the polishing pad is 90 to 95 r/min.
9. The method of any of claims 1-8, wherein the chemical mechanical polishing removes impurities and oxides from the wafer surface;
preferably, the oxide on the surface of the wafer comprises tetraethoxysilane.
10. Method according to any of claims 1-9, characterized in that the method comprises the steps of:
The method comprises the following steps of grinding a wafer by adopting chemical mechanical grinding equipment, wherein the chemical mechanical grinding equipment sequentially comprises a grinding head, a grinding pad and a grinding table from top to bottom, a retaining ring is a structural component of the grinding head, and the wafer is positioned between the grinding head and the grinding pad; the polishing pad in the chemical mechanical polishing device is of a double-layer structure, the upper layer structure of the polishing pad is in contact with the surface of a wafer, the wafer is surrounded and fixed by a retaining ring, and the edge area of the wafer is in contact with both the polishing pad and the retaining ring;
the upper layer structure of the grinding pad is made of polyurethane, the hardness is 58-68 SHD, the thickness is 1.0-2.0 mm, and the diameter of a micropore is 12-17 mu m; the material of the lower layer structure of the grinding pad comprises non-woven fabric, the hardness is 71-89 SHA, the thickness is 0.5-1.0 mm, and the diameter of a micropore is 18-22 mu m; the upper layer structure and the lower layer structure are combined through a bonding layer; the hardness of the lower layer structure of the grinding pad is 4-10% higher than that of the lower layer structure of the grinding pad on the premise of improvement so as to improve the grinding rate of the edge area of the wafer;
during the chemical mechanical polishing, the pressure applied to the wafer by the polishing head is 4-6 psi, the pressure applied to the retaining ring is 6-8 psi, the rotating speed of the wafer is 85-90 r/min, the rotating speed of the polishing pad is 90-95 r/min, the rotating directions of the wafer and the retaining ring are the same, and impurities and oxides on the surface of the wafer are removed through the chemical mechanical polishing, so that the surface of the wafer is cleaned.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210203428.0A CN114515994A (en) | 2022-03-03 | 2022-03-03 | Method for improving grinding rate of edge area of wafer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210203428.0A CN114515994A (en) | 2022-03-03 | 2022-03-03 | Method for improving grinding rate of edge area of wafer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114515994A true CN114515994A (en) | 2022-05-20 |
Family
ID=81598439
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210203428.0A Pending CN114515994A (en) | 2022-03-03 | 2022-03-03 | Method for improving grinding rate of edge area of wafer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114515994A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115799224A (en) * | 2023-01-09 | 2023-03-14 | 紫光同芯微电子有限公司 | Wafer surface structure |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11333699A (en) * | 1998-03-24 | 1999-12-07 | Sony Corp | Polishing pad, polishing device and polishing method |
| CN1316939A (en) * | 1998-07-10 | 2001-10-10 | 卡伯特微电子公司 | Polishing pad for semiconductor substrate |
| CN1813340A (en) * | 2003-07-02 | 2006-08-02 | 株式会社荏原制作所 | Polishing apparatus and polishing method |
| CN101175603A (en) * | 2005-05-18 | 2008-05-07 | 东洋橡胶工业株式会社 | Polishing pad, process for producing the same, and process for producing semiconductor device using said polishing pad |
| CN101489721A (en) * | 2006-08-28 | 2009-07-22 | 东洋橡胶工业株式会社 | Polishing pad |
| CN202825512U (en) * | 2012-10-11 | 2013-03-27 | 中芯国际集成电路制造(北京)有限公司 | Grinding pad and chemical machinery grinding machine |
| CN105917448A (en) * | 2013-12-20 | 2016-08-31 | 应用材料公司 | Printed chemical mechanical polishing pad having controlled porosity |
| CN112720282A (en) * | 2020-12-31 | 2021-04-30 | 湖北鼎汇微电子材料有限公司 | Polishing pad |
| CN112743450A (en) * | 2019-10-30 | 2021-05-04 | Skc索密思株式会社 | Polishing pad, method of manufacturing the same, and method of manufacturing semiconductor device using the same |
| CN112757154A (en) * | 2021-01-22 | 2021-05-07 | 湖北鼎汇微电子材料有限公司 | Polishing pad |
| CN112809550A (en) * | 2020-12-31 | 2021-05-18 | 湖北鼎汇微电子材料有限公司 | Polishing pad |
-
2022
- 2022-03-03 CN CN202210203428.0A patent/CN114515994A/en active Pending
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11333699A (en) * | 1998-03-24 | 1999-12-07 | Sony Corp | Polishing pad, polishing device and polishing method |
| CN1316939A (en) * | 1998-07-10 | 2001-10-10 | 卡伯特微电子公司 | Polishing pad for semiconductor substrate |
| CN1813340A (en) * | 2003-07-02 | 2006-08-02 | 株式会社荏原制作所 | Polishing apparatus and polishing method |
| CN101175603A (en) * | 2005-05-18 | 2008-05-07 | 东洋橡胶工业株式会社 | Polishing pad, process for producing the same, and process for producing semiconductor device using said polishing pad |
| CN101489721A (en) * | 2006-08-28 | 2009-07-22 | 东洋橡胶工业株式会社 | Polishing pad |
| CN202825512U (en) * | 2012-10-11 | 2013-03-27 | 中芯国际集成电路制造(北京)有限公司 | Grinding pad and chemical machinery grinding machine |
| CN105917448A (en) * | 2013-12-20 | 2016-08-31 | 应用材料公司 | Printed chemical mechanical polishing pad having controlled porosity |
| CN112743450A (en) * | 2019-10-30 | 2021-05-04 | Skc索密思株式会社 | Polishing pad, method of manufacturing the same, and method of manufacturing semiconductor device using the same |
| CN112720282A (en) * | 2020-12-31 | 2021-04-30 | 湖北鼎汇微电子材料有限公司 | Polishing pad |
| CN112809550A (en) * | 2020-12-31 | 2021-05-18 | 湖北鼎汇微电子材料有限公司 | Polishing pad |
| CN112757154A (en) * | 2021-01-22 | 2021-05-07 | 湖北鼎汇微电子材料有限公司 | Polishing pad |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115799224A (en) * | 2023-01-09 | 2023-03-14 | 紫光同芯微电子有限公司 | Wafer surface structure |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101862139B1 (en) | Method for manufacturing semiconductor wafer | |
| KR100882389B1 (en) | Wafer manufacturing method, polishing apparatus, and wafer | |
| US6899602B2 (en) | Porous polyurethane polishing pads | |
| JP5210952B2 (en) | Polishing pad | |
| US7648890B2 (en) | Process for producing silicon wafer | |
| KR100818683B1 (en) | Mirror chamfered wafer, mirror chamfering polishing cloth, and mirror chamfering polishing machine and method | |
| US7429209B2 (en) | Method of polishing a glass substrate for use as an information recording medium | |
| US20020006768A1 (en) | Polishing method using an abrading plate | |
| US20080220700A1 (en) | Glass Substrate for Information Recording Medium and Method for Producing the Same | |
| KR102382812B1 (en) | Silicon Wafer Polishing Method | |
| KR20130005267A (en) | Abrasive head and abrading device | |
| CN107398779A (en) | A kind of final polishing method of wafer | |
| CN114515994A (en) | Method for improving grinding rate of edge area of wafer | |
| JP5309692B2 (en) | Polishing method of silicon wafer | |
| JP3975047B2 (en) | Polishing method | |
| KR100528884B1 (en) | An edge polishing machine and edge polishing method thereby | |
| JP4103808B2 (en) | Wafer grinding method and wafer | |
| CN114523340B (en) | Complete grinding and polishing equipment and grinding and polishing method | |
| JP6330628B2 (en) | Manufacturing method of glass substrate | |
| CN112372509B (en) | Method and apparatus for changing initial state of polishing pad to hydrophilicity | |
| JP3611029B2 (en) | Semiconductor substrate polishing holding plate | |
| JP2018049980A (en) | Semiconductor device manufacturing method | |
| JP6717706B2 (en) | Wafer surface treatment equipment | |
| CN113327852B (en) | Chemical mechanical polishing method for wafer surface | |
| US20230197455A1 (en) | Methods for polishing semiconductor substrates |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |