JP2004022886A - Polishing member, polishing device using the same, semiconductor device manufacturing method using it, and semiconductor device manufactured through the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing member which is capable of sufficiently satisfying a requirement for flatness and the uniformity of the surface of a semiconductor wafer subjected to a polishing process and restraining the semiconductor wafer from increasing in manufacturing cost. <P>SOLUTION: The polishing member 4 is composed of a polishing pad 41 which polishes the semiconductor wafer being a target object while abutting against the surface of the semiconductor wafer, and a polishing support 42 provided with an adhering surface 42p which adhesively holds the polishing pad 41 in a horizontal position. The adhering surface 42p has a desired compressive modulus. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a polishing member for polishing and flattening the surface of a substrate such as a wafer used for a semiconductor device, a polishing apparatus using the polishing member, a method for manufacturing a semiconductor device using the device, and a method for manufacturing the same. And a semiconductor device manufactured by the same.
[0002]
[Prior art]
In recent years, as ICs have become finer and more complex, and the number of layers of multilayer wiring has increased, the steps on the IC surface have become increasingly larger, and the accuracy of polishing the surface of the semiconductor wafer after forming each thin film has become important. Is coming. If the accuracy of the polishing performed after the formation of the thin film is poor, the thin film at the stepped portion may be locally thinned, or insulation failure of the wiring, short circuit, or the like may occur. In the lithography process, if the surface of the wafer has many irregularities, the wafer may be out of focus and a fine pattern may not be formed.
[0003]
Therefore, as a polishing device for flattening the surface of a semiconductor wafer, an object holding device for holding a semiconductor wafer, which is an object to be polished, and a sheet for polishing the semiconductor wafer and abutting against the surface to be polished of the semiconductor wafer for polishing And a polishing support having a polishing surface having an affixing surface for adhering and holding the polishing pad in a planar shape. The polishing member is provided on a surface to be polished of a semiconductor wafer held by an object holding device. 2. Description of the Related Art There has been known an apparatus configured to polish a polished surface of a semiconductor wafer by relatively moving an object holding device and a polishing member while being in contact with each other. In addition to such mechanical polishing, a CMP apparatus for performing chemical mechanical polishing in which a polishing agent (polishing liquid) is supplied to a contact surface between a polishing pad and a semiconductor wafer to promote the polishing by a chemical action of the polishing agent. Is also known.
[0004]
Incidentally, in a polishing process of a semiconductor wafer performed by using such a CMP apparatus, a predetermined accuracy is required for a polishing state of the semiconductor wafer, such as flatness of a surface to be polished and uniformity of polishing. The polishing state of these semiconductor wafers is greatly affected by the material hardness and thinness of the polishing pad.
[0005]
For example, when the polishing pad is made of a hard material, the flatness is improved, but there is a problem that the uniformity of polishing is reduced because the polishing pad hardly follows the uneven shape of the semiconductor wafer surface. When the polishing pad is made of a soft material, there is a problem in that the polishing pad easily follows the uneven shape of the surface of the semiconductor wafer and the polishing uniformity is improved, but the flatness is reduced.
[0006]
In addition, when the polishing pad is made thinner, the flatness is improved, but it is difficult to follow the semiconductor wafer surface, and the polishing uniformity is reduced. When the polishing pad is made thicker, the polishing pad is easily made to follow the semiconductor wafer surface, and the polishing uniformity is improved, but the flatness is reduced. There was a problem of doing it.
[0007]
[Problems to be solved by the invention]
Therefore, by compensating for the disadvantages of the polishing pad material such as hard and soft and thin, and combining the advantages thereof, it is possible to perform favorable polishing with good flatness and uniformity of the surface to be polished (of a semiconductor wafer). There is a polishing member that has been used. As one example, a polishing pad provided on a polishing support is made of a hard material and has a predetermined thickness. In such a polishing member, the requirement for the flatness of the surface to be polished can be satisfied by forming the polishing pad from a hard material, and the rigidity is reduced by having a predetermined thickness to reduce the polishing uniformity. It can meet the demand.
[0008]
However, since the material constituting the polishing pad is expensive, the polishing member having a configuration in which the polishing pad has a thickness as described above is in a state where the polishing pad is thick when the polishing pad is replaced due to wear. In such a case, it is necessary to replace the polishing pad with a new polishing pad, resulting in a problem that the manufacturing cost is increased.
[0009]
The present invention has been made in view of such a problem, and can satisfy the demand for the flatness and uniformity of the surface polishing of a semiconductor wafer to be polished with sufficient accuracy and suppress the manufacturing cost. It is an object of the present invention to provide a polishing member capable of performing the above, a polishing apparatus using the polishing member, a method of manufacturing a semiconductor device using the apparatus, and a semiconductor device manufactured by the manufacturing method.
[0010]
[Means for Solving the Problems]
In order to achieve such an object, according to the present invention, a polishing pad having a polishing pad that abuts on a surface to be polished of an object to be polished and a sticking member that sticks and holds the polishing pad in a planar shape is provided. And the attaching member is configured to have a desired compression elastic modulus.
[0011]
In addition, it is preferable that the polishing support of the polishing member includes a main body and the attaching member, and the attaching member is a sheet-like elastic plate having a predetermined thickness.
[0012]
Preferably, the elastic plate of the polishing member is made of non-foamable or foamable rubber or urethane foam.
[0013]
The desired compression modulus of the polishing member may be substantially the same as the compression modulus of the polishing pad.
[0014]
The polishing apparatus according to the present invention includes an object holding device that holds an object to be polished, and the above-described polishing member that polishes the object to be polished, wherein the polishing member is brought into contact with the object to be polished while The object holding device and the polishing member are relatively moved to polish the polished surface of the object to be polished.
[0015]
A semiconductor device manufacturing method according to the present invention includes a step of flattening a surface of a semiconductor wafer by using the above polishing apparatus. Further, a semiconductor device according to the present invention is manufactured by the above-described semiconductor device manufacturing method.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, a CMP apparatus (chemical mechanical polishing apparatus) 1 according to the present invention will be described below with reference to the drawings.
[0017]
The CMP apparatus 1 has a plurality of polishing heads supported by the polishing head transfer mechanism 7 with the polishing surface facing downward. The polishing head includes a polishing head for rough polishing 2a, a polishing head for medium polishing 2b, and a polishing head for finish polishing 2c (however, the polishing head for finish polishing 2c is not shown in the drawing). The polishing head 2 will be described using reference numeral 2. The polishing head 2 is attached to a rotating shaft 3 extending downward from the polishing head transfer mechanism 7, and is configured to be rotationally driven by a motor (not shown) in the polishing head transfer mechanism 7. The polishing head 2 has a pad holding mechanism at the lower end, and the polishing member 4 is held by the pad holding mechanism with the polishing surface facing downward, and is detachably attached to the lower end of the polishing head 2.
[0018]
In the CMP apparatus 1, a pad conditioning mechanism 5 is provided, in which dressing of the polishing member 4 is performed. The pad conditioning mechanism 5 has a dressing disk 5a, a spray nozzle 5b, and a rotatable cleaning brush 6 arranged as shown in the figure.
[0019]
The polishing head transfer mechanism 7 has a rail 7a, a feed screw 7b, and a moving body 7c screwed to the feed screw 7b, and the polishing head 2 is attached to the moving body 7c via a rotating shaft 3. The feed screw 7b is driven to rotate by a motor 7f via gears 7d and 7e, and the moving body 7c is moved in the x direction shown in FIG. The polishing head 2 is moved up and down in the z direction shown in FIG. 2 by an elevating mechanism (not shown) provided in the moving body 7c. Each of the polishing heads 2a, 2b, and 2c is provided with the above-described mechanism, and is independently moved in the x and z directions. , Z are also moved in the y direction perpendicular to the z direction.
[0020]
The CMP apparatus 1 is further provided with a storage cassette 9 for storing the wafer W to be polished, and a wafer transfer robot 10 for transferring the wafer W to the storage cassette 9. The wafer transfer robot 10 is a robot for transferring an unpolished wafer W from the storage cassette 9 to the index table 12 and unloading the polished wafer W, and temporarily transferring the wafer W along the transfer path. , A temporary wafer mounting table 11 is provided.
[0021]
The index table 12 is provided with four rotatable wafer chuck mechanisms 20 provided at equal intervals on the same circumference with the shaft 12e as an axis, and a wafer loading & unloading zone indicated by reference numeral S1. , A rough polishing zone denoted by reference symbol S2, a medium polishing zone denoted by reference symbol S3, and a finish polishing zone denoted by reference symbol S4. Accordingly, each wafer chuck mechanism 20 sequentially moves to the wafer loading & unloading zone S1, the rough polishing zone S2, the medium polishing zone S3, and the finish polishing zone S4 according to the rotation of the index table 12, Above each zone, the polishing member 4a for coarse polishing held by the polishing head 2a for coarse polishing, the polishing member 4b for medium polishing held by the polishing head 2b for medium polishing, and the polishing head 2c for finish polishing are respectively held. The finished polishing member 4c is located.
[0022]
The wafer transfer robot 10 is also used as an unloading transfer robot for transferring the polished wafer W, and the polished wafer W is transferred onto the belt conveyor 16 by the robot 10, and the wafer is cleaned by the belt conveyor 16. It is sent to the mechanism 17 and washed. In addition, it also has a chuck dresser 14a and a chuck cleaning mechanism 14b for dressing and cleaning the wafer chuck mechanism 20 of the index table 12.
[0023]
As described above, the CMP apparatus 1 according to the present invention has been described, but the scope of the present invention is not limited to the above. For example, in the CMP apparatus 1 shown in the above embodiment, the wafer W to be polished is held by the wafer chuck mechanism 20 on the index table 12, and the polishing member 4 is pressed from above. Instead of such a configuration, a configuration in which the wafer W is placed above the polishing surface of the polishing member 4 and the surface to be polished of the wafer W is pressed against the polishing surface of the polishing member 4 from above may be employed. In the above embodiment, the polishing member 4 has a smaller diameter than the wafer W. However, this is merely an example, and conversely, the wafer W may have a smaller diameter than the polishing member 4.
[0024]
When the polishing pad 41 of the polishing member 4 described below is worn out by performing the polishing operation on the wafer W using the CMP apparatus 1 having the above configuration, the spindle shaft 3 is retracted in the left-right direction (x-axis direction). The polishing member 4 is pressed against the dressing disk 5 a of the conditioning mechanism 5, and the surface of the polishing pad 41 is cut by rotating the polishing member 4 to repair the polishing member 4. When the wear of the polishing pad 41 becomes a predetermined amount or more due to the polishing of the wafer W or the repair of the polishing pad 41, the polishing pad 41 is replaced with a new pad.
[0025]
Here, the configuration of the polishing member 4 according to the present invention will be described below with reference to FIG. FIG. 3A is an explanatory cross-sectional view showing the polishing member 4, and FIG. 3B is a perspective view of the polishing member 4.
[0026]
The polishing member 4 includes a polishing pad 41 that abuts on a surface to be polished of a semiconductor wafer to be polished and performs polishing, a polishing support 42 having an attaching surface 42p for attaching and holding the polishing pad 41 in a planar shape. It is composed of
[0027]
The polishing support 42 includes a pad plate 42a and a sheet-like elastic plate 42b provided on the side of the attaching surface 42p of the pad plate 42a as an attaching member and having a predetermined thickness. The elastic plate 42b has substantially the same compression modulus as the polishing pad 41.
[0028]
Further, the polishing support 42 is not limited to the above-described embodiment as long as the attaching member for attaching and holding the polishing pad 41 can secure a desired compression elastic modulus. For example, the polishing member 4 may be configured using a polishing support 42 composed of a single-layer plate or a plate in which three or more layers are stacked.
[0029]
The polishing pad 41 used for the polishing member 4 having such a configuration includes a hard foamed urethane sheet, a polyester fiber nonwoven fabric, a felt, a polyvinyl alcohol fiber nonwoven fabric, a nylon fiber nonwoven fabric, and a foamable urethane resin solution cast on these nonwoven fabrics. Then, a foamed and cured product (for example, IC1000 manufactured by Rodale) is used. The pad plate 42a is made of metal such as stainless steel or aluminum. It is preferable that non-foamable or foamable rubber, urethane foam, or the like is used as the elastic plate 42b.
[0030]
With such a configuration, the polishing member 4 of the present invention allows the polishing support 42 to provide a desired compression elastic modulus on the attachment surface 42p (this depends on the degree of flatness and polishing uniformity required for the object to be polished). For example, in this embodiment, almost the same compression elastic modulus as that of the polishing pad 41 is set.), So that the expensive polishing pad 41 can be made thin. . As a result, the requirement for the flatness and uniformity of the surface polishing of the semiconductor wafer can be satisfied with sufficient accuracy, and the manufacturing cost of the polishing member 4 can be suppressed. Therefore, since the polishing pad 41 is replaced after the polishing pad 41 is used until it becomes thinner than before, the cost of replacing the polishing member 4 as described above can be suppressed.
[0031]
Here, a configuration in which the polishing member 4 is fixedly held at the lower end of the polishing head 2 (of the CMP apparatus 1) will be described with reference to FIG. FIG. 4 is an explanatory sectional view of the polishing head 2 and the polishing member 4. The upper surface of the pad plate 42a of the polishing member 4 is a bonding surface portion for bonding to the polishing head 2, and a concave portion 40d in which the positioning projection 23 of the head engages and the positioning pin 24 of the head engage in the surface. And a recess 40e. In addition, the concave and convex portions for positioning the polishing head and the polishing member may be provided in reverse. For example, the positioning protrusions and the positioning pins may be provided on the upper surface of the polishing member, and the recesses into which they are engaged may be provided on the surface of the polishing head.
[0032]
The polishing head 2 is configured to join the polishing members 4 by suction under a negative pressure. As shown in a cross section in FIG. 4, a flow path 21 communicating with a flow path 3 a provided in the spindle shaft 3 is provided inside the polishing head 2. Further, a concave portion 22 communicating with the flow path 21 is provided in a lower surface portion to which the polishing member 4 is joined. Therefore, the polishing member 4 is joined to the polishing head 2, and a vacuum pump (not shown) communicating with the flow path 3 a of the spindle shaft 3 is operated to depressurize the flow path 3 a and the flow path 21. The polishing member 4 can be fixedly held by negative pressure suction. As described above, the positioning projection 23 and the positioning pin 24 are provided on the lower surface of the polishing head 2 for positioning during the fixed holding. When removing the polishing member 4 fixed and held by the negative pressure suction from the polishing head 2, the operation of the vacuum pump may be stopped and the suction force of the vacuum pump may be eliminated.
[0033]
Next, an embodiment of a method for manufacturing a semiconductor device according to the present invention will be described. FIG. 5 is a flowchart illustrating a semiconductor device manufacturing process. When the semiconductor manufacturing process is started, first, an appropriate processing step is selected from steps S201 to S204 to be described next in S200, and the process proceeds to any one of the steps.
[0034]
Here, step S201 is an oxidation step of oxidizing the surface of the wafer. Step S202 is a CVD step of forming an insulating film or a dielectric film on the wafer surface by CVD or the like. Step S203 is an electrode forming step of forming electrodes on the wafer by vapor deposition or the like. Step S204 is an ion implantation step of implanting ions into the wafer.
[0035]
After the CVD step (S202) or the electrode forming step (S203), the process proceeds to step S205. Step S205 is a CMP process. In the CMP process, the polishing apparatus according to the present invention performs planarization of an interlayer insulating film, polishing of a metal film on the surface of a semiconductor device, formation of damascene by polishing of a dielectric film, and the like.
[0036]
After the CMP step (S205) or the oxidation step (S201), the process proceeds to step S206. Step S206 is a photolithography step. In this step, a resist is applied to the wafer, a circuit pattern is printed on the wafer by exposure using an exposure device, and the exposed wafer is developed. Further, the next step S207 is an etching step of removing portions other than the developed resist image by etching, removing the resist, and removing unnecessary resist after etching.
[0037]
Next, it is determined in step S208 whether all necessary processes have been completed. If not, the process returns to step S200, and the previous steps are repeated to form a circuit pattern on the wafer. If it is determined in step S208 that all steps have been completed, the process ends.
[0038]
In the semiconductor device manufacturing method according to the present invention, since the CMP apparatus 1 (polishing apparatus) according to the present invention is used in the CMP step, the flatness and uniformity of the surface polishing of the semiconductor wafer are maintained with high accuracy, and the yield of the CMP step is maintained. While improving the quality of the semiconductor device, an expensive polishing pad can be used until it becomes thinner than before, so that there is an effect that a semiconductor device can be manufactured at a lower cost than a conventional semiconductor device manufacturing method. The polishing apparatus according to the present invention may be used in a CMP step of a semiconductor device manufacturing process other than the above-described semiconductor device manufacturing process. Further, in a semiconductor device manufactured by this semiconductor device manufacturing method, a wafer having a high flatness is used, so that an inexpensive device having good performance with few problems such as wiring insulation failure and short circuit is obtained.
[0039]
【The invention's effect】
ADVANTAGE OF THE INVENTION As mentioned above, according to this invention, the grinding | polishing member which can satisfy | fill the requirement with respect to the flatness and uniformity of the surface polishing of the semiconductor wafer which is a grinding | polishing object with sufficient precision, and can hold down a manufacturing cost is provided. be able to.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a CMP apparatus according to the present invention.
FIG. 2 is a perspective view showing a part of the CMP apparatus.
FIG. 3 is a sectional explanatory view and a perspective view showing a polishing member according to the present invention.
FIG. 4 is an explanatory sectional view of a polishing head using the polishing member.
FIG. 5 is a flowchart showing a semiconductor device manufacturing process according to the present invention.
[Explanation of symbols]
1 CMP equipment (polishing equipment)
4 Polishing Member 41 Polishing Pad 42 Polishing Support 42a Pad Plate (Main Body)
42b elastic plate (sticking member)
42p Sticking surface W Semiconductor wafer (object to be polished)

Claims (7)

A polishing member comprising a polishing pad having an attaching member for attaching and holding the polishing pad in a planar shape, and a polishing pad for performing polishing by contacting the surface to be polished of the object to be polished,
A polishing member, wherein the attaching member has a desired compression elastic modulus. 2. The polishing member according to claim 1, wherein the polishing support includes a main body and the attaching member, and the attaching member is a sheet-shaped elastic plate having a predetermined thickness. 3. The polishing member according to claim 2, wherein the elastic plate is made of non-foamable or foamable rubber or urethane foam. The polishing member according to any one of claims 1 to 3, wherein the desired compression elastic modulus is substantially the same as the compression elastic modulus of the polishing pad. An object holding device for holding an object to be polished, and the polishing member according to any one of claims 1 to 4 for polishing the object to be polished, while the polishing member is in contact with the object to be polished. A polishing apparatus characterized in that the object holding device and the polishing member are relatively moved to polish a surface to be polished of the object to be polished. A method for manufacturing a semiconductor device, comprising: flattening a surface of a semiconductor wafer using the polishing apparatus according to claim 5. A semiconductor device manufactured by the semiconductor device manufacturing method according to claim 6.

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