US20020013122A1

US20020013122A1 - Process and apparatus for chemimechanically polishing a substrate

Info

Publication number: US20020013122A1
Application number: US09/905,898
Authority: US
Inventors: Isao Sugaya; Naoki Sasaki; Kiyoshi Tanaka
Original assignee: Nikon Corp
Current assignee: Nikon Corp
Priority date: 1999-12-22
Filing date: 2001-07-17
Publication date: 2002-01-31

Abstract

An apparatus for chemimechanically polishing a substrate by the steps of causing a chuck to hold the substrate having a metal film or devices such that the surface of a metal film or an insulating film of the substrate is caused to face upwards, pressing the surface of a polishing pad bonded to a joining plate pivotally borne by a spindle shaft having the axis arranged to be perpendicular to the substrate on the surface of the substrate, while supplying polishing solution to a boundary between the surfaces of the pad and the substrate, rotating the chuck holding the substrate and the polishing pad, and reciprocating the polishing pad horizontally on the surface of the substrate so that at least a portion of the metal film or the insulating film is removed. The apparatus for chemimechanically polishing a substrate includes a guide member disposed on the horizontal plane extended from the surface of the substrate held by the chuck and capable of supporting the surface of a portion of the polishing pad projecting over the outer surface of the substrate owing to reciprocating of the polishing pad on the substrate such that the guide member is provided independently from the chuck.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of the earlier filing date of U.S. patent application Ser. No. 09/539,884, filed Mar. 31, 2000, entitled “Process and Apparatus for Chemimechanically Polishing Substrate,” the entirety of which is incorporated herein by reference.[0001]

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

The present invention relates to a process and an apparatus for chemimechanically polishing a substrate capable of realizing excellent uniformity of a substrate which has been chemimechanically polished. The process and apparatus for chemimechanically polishing a substrate according to the present invention are effective in removing a metal films formed on an insulating layer of the substrate, an insulating film formed on the surface of a substrate incorporating a metal film pattern on which the insulating film is formed and a STI (Shallow Trench Insulation) P-TEOS layer.

The present invention also concerns a method far manufacturing a semiconductor device as well as a semiconductor device.

DISCUSSION OF THE BACKGROUND

A chemimechanical polishing apparatus has been known (refer to JP-A-10-303152, JP-A-11-156711, U.S. Pat. No. 2,968,784 and U.K. Patent Laid-Open No. 2,331,948). The apparatus incorporates a spindle shaft, which pivotally supports a polishing pad. While supplying polishing slurry, which is equipped through a spindle shaft to the surface of the polishing pad, the pad is pressed on a surface of a substrate held by a chuck. The polishing pad, which is rotating, is reciprocated (swung) on the surface of the substrate and oscillating on the surface of the substrate. Thus, the substrate is chemimechanically polished (CMP-polished). FIGS. 5 to 8 show a chemimechanically polishing apparatus.

FIG. 5 is a perspective view showing an example of the chemimechanical polishing apparatus. FIG. 6 is a perspective view showing a mechanism for moving a polishing pad. FIG. 7 is a partial cross-sectional view showing the polishing pad and a conditioning unit. FIG. 8 is a cross-sectional view showing a polishing head.

In the

chemimechanical polishing apparatus

1 having an index table shown in FIGS. 5 to 7, reference numeral 2 represents a polishing head, 2 a represents a polishing head for rough polishing, 2 b represents a finish polishing head, 3 represents an axis of rotation, 3 a represents a motor, 3 b represents a gear, 3 c represents a pulley, 3 d represents a gear, 4 represents a polishing pad, 5 represents a pad conditioning mechanism, 5 a represents a dressing disk, 5 b represents an injection nozzle for washing, 5 c represents a protective cover, 6 represents a rotative cleaning brush, 7 represents a mechanism for moving the polishing head, 7 a represents a rail, 7 b represents a moving screw and 7 c represents a movable member screwed to the moving screw so that the polishing head 2 is attached.

Reference numerals

7 d and 7 e represent gears, 7 f represents a motor, 8 represents an air cylinder which is a mechanism for vertically moving the head, 9 represents a cassette for accommodating wafers w, 10 represents a loading/carrying robot, 11 represents a frame on which the wafer is temporarily placed and 12 represents a rotative index table having four

wafer chuck mechanisms

12 a, 12 b, 12 c and 12 d disposed radially of a center axis 12 e, at the same intervals. The table 12 is sectioned into a wafer loading zone s1, a rough polishing zone s2, a finish polishing zone s3 and a wafer unloading zone s4.

Reference numeral

13 represents a unloading/carrying robot, 14 a represents a chuck dresser, 14 b represents a chuck cleaning mechanism, 15 represents a provisional rest on which the wafer is temporarily placed, 16 represents a belt conveyor and 17 represents a wafer cleaning mechanism.

In the

polishing head

2 shown in FIG. 8, a projecting edge 21 a of a plate 21 is supported by a flange 20 a of a pressurizing cylinder 20 of the head 2. The polishing pad (an annular polishing cloth) 4 is held by the plate 21 through a polishing-cloth joining plate 22. A diaphragm 23 is arranged in a pressurizing chamber 20 b of a pressurizing cylinder 20. Compressed air is forcibly injected into the pressurizing chamber 20 b through the inside portion of the spindle shaft 3. The pressure and the diaphragm 23 cause the pad 21 to be swingably in the three-dimensional (X, Y and Z) directions. Moreover, the pad 4 is kept horizontally with respect to the surface of the wafer.

A

pipe

24 for supplying polishing solution or cleaning solution is disposed in the central portion of the head 2. The leading end of the pipe bypasses a central through portion 4 a to face the reverse side of the annular polishing pad. Thus, the polishing solution, or etching or cleaning solution is supplied to the surface of the metal layer of the substrate through the annular member.

A process for polishing the wafer (the substrate) having the metal film formed on an insulating layer by using the

chemimechanical polishing apparatus

1 is performed as follows.

(1) A wafer w 1 is extracted from the cassette 9 by the arm of the carrying robot 10 so as to be placed on the temporarily-placing frame 11 such that the surface of the metal film faces upwards. Thus, the reverse side of the wafer w1 is cleaned. Then, the wafer w1 is moved to a wafer loading zone s1 of the index table 12 by the carrying robot 10 so as to be sucked by the chucking mechanism 12 a.

(2) The index table 12 is clockwise rotated by 90° so as to introduce the wafer w1 into the first polishing zone s2. Then, the spindle shaft 3 is moved downwards so that the polishing pad 4 joined to the head 2 a is pressed against the wafer w1. Then, the spindle shaft 3 and the shaft of the chucking mechanism are rotated so that the wafer is chemimechanically polished. In the foregoing period, a new wafer w2 is placed on the temporal placing frame 11, and then the wafer w2 is moved to the wafer loading zone s1 so as to be sucked by the chucking mechanism 12 b.

During the CMP process of the wafer, polishing solution is supplied to the reverse side of the annular member 4 (pad) from the supply pipe 24 provided for a hollow portion of the spindle shaft 3 at a rate of 10 ml/minute to 100 ml/l. The number of revolutions of the wafer sucked by the chucking table is 200 rpm to 800 rpm, preferably 200 rpm to 600 rpm. The number of revolutions of the polishing pad is 400 rpm to 3000 rpm, preferably 400 rpm to 1000 rpm. The pressure which is applied to the substrate is 1.2 psi to 3 psi.

In the CMP process, a position of ⅛ point or ½ point (about 25 mm which is a ¼ point when a wafer having a diameter of 200 mm and a polishing pad having an outer diameter of 150 mm) of the radius of the substrate which is, by a ball screw, displaced from the central point 0 of the wafer to the left is a oscillating start point (Xo) for the polishing pad 4. A position displaced from the oscillating start position to the left (toward the outer end of the wafer) for a distance of about 10 mm to 50 mm, preferable 20 mm to 40 mm is a oscillating end point (Xe). The polishing pad 4 is reciprocating in the lateral direction in the region having a length (L) between the oscillating start point (Xo) and the swing end point (Xe) (see FIG. 9).

After the chemimechanical polishing process in the first polishing zone s 2 has been performed for a required time, the spindle shaft 3 is upwards moved, and then it is withdrawn to the right so as to be moved to a position above the rotative brush 5. While spraying high-pressure jet water through the nozzle 5 b, the rotative brush 5 is operated to remove trash of abrasive particles and polished metal which are adhered to the right side of the pad. Then, the polishing pad is again moved to the left so that the polishing pad is put on standby above the polishing zone s2.

(3) The index table is clockwise rotated by 90° to introduce the polished wafer w 1 into a second polishing zone s3. Then, the spindle shaft 3 is moved downwards so as to press the polishing pad 9 joined to the head 2 b against the wafer w1 which has roughly been polished. Then, the spindle shaft 3 and the shaft of the chucking mechanism are rotated so that final chemimechanical polishing of the wafer is performed. After the final polishing process has been completed, the spindle shaft 3 is upwards moved. Then, the spindle shaft 3 is withdrawn to the right. The polishing pad joined to the head 2 b is cleaned by the cleaning mechanism 5. Then, the polishing pad is again moved to the left so that the polishing pad is put on standby above the second polishing zone s3.

In the foregoing period, a new wafer w 3 is placed on the temporarily-placing frame 11 so as to be moved to the wafer loading zone s1. Then, the wafer w3 is sucked by the chucking mechanism 12 c. In the first polishing zone s2, rough chemimechanical polishing of the wafer w2 is performed.

(4) The index table 12 is clockwise rotated by 90° to introduce the polished wafer w1 into the unloading zone s4. The unloading/carrying robot 13 is operated to move the wafer subjected to final polishing to the provisional rest 15. The reverse side of the wafer is cleaned, and then the unloading/carrying robot 13 is operated to introduce the wafer into the moving mechanism incorporating a belt conveyor 16. Then, cleaning solution is sprayed to the patterned surface of the wafer through the nozzle 17 to clean the wafer. Then, the wafer is introduced into a next process.

In the foregoing period, a new wafer w 4 is placed on the temporarily-placing frame 11 so as to be moved to the wafer loading zone s1. Then, the wafer w4 is sucked by the chucking mechanism 12 d. In the first polishing zone s2, rough chemimechanical polishing of the wafer w3 is performed. In the second polishing zone s3, final chemimechanical polishing of the wafer w2 is performed.

(5) The index table 12 is clockwise rotated by 90° to repeat steps similar to the steps (2) to (4) so that the wafer is chemimechanically polished.

The reason why the chemimechanical polishing process is divided into the first polishing step which is the rough polishing step and the second polishing step which is the final step lies in that the throughput time must be shortened. The CMP process is sometimes performed by one step. As an alternative to this, the process is sometimes divided into three steps consisting of rough polishing, medium polishing and final polishing to furthermore shorten the throughput time. When the CMP process having the three steps is performed, the zone s 1 is used as a zone in which both of wafer loading and wafer unloading are performed. The zone s2 is used as the first polishing zone, the zone s3 is used as the second polishing zone and the zone s4 is used as the third (final) polishing zone (in a case of a CMP apparatus shown in FIG. 1 to be described later).

As for the material of the polishing pad, the first polishing pad and the second polishing pad may be made of different materials. The polishing solution (slurry) is sometimes varied between the steps.

The foregoing chemimechanical polishing process is performed as described above such that the substrate is held by the chuck table in such a manner that the surface of the metal film or the surface of the insulating layer (including a surface in which the two types are mixed) faces upwards. Then, the surface of the

polishing pad

4 bonded to the joining plate pivotally borne by the spindle shaft having the perpendicular axis is pressed against the surface of the substrate. The polishing abrasive slurry is equipped between the surface of the pad and the substrate. Then, the substrate and the polishing pad are rotated and slid each other. While reciprocating and swinging the polishing pad, at least a portion of the metal film or the insulating film on the surface of the substrate is removed. If the polishing pad, which performs a reciprocation and a swing, is deviated over the edge of the substrate when the polishing pad is reciprocatively swung, no means for supporting the deviated portion of the polishing pad is provided. Therefore, slight inclination of the spindle shaft easily occurs. Hence it follows that a projection having a somewhat large thickness is undesirably formed in the inside portion adjacent to the periphery of the substrate subjected to the CMP process. Thus, there arises a problem in that non-uniformity of the substrate subjected to the CMP process occurs.

Although the spindle-shaft inclining mechanism disclosed in U.S. Pat. No. 3,007,678 may be provided for the apparatus to correct the non-uniform portion, there arises a problem in that the cost of the apparatus is expensive. What is worse, the overall size of the apparatus is enlarged excessively and the area required to install the apparatus cannot be reduced.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a chemimechanical polishing apparatus which is structured to perform a CMP process such that a polishing pad having a small diameter with respect to the diameter of the substrate is used in a state where the polishing pad is oscillating or reciprocating and which is capable of permitting a substrate to be free from non-uniformity to be obtained.

According to a first aspect of the invention, there is provided an apparatus for chemimechanically polishing a substrate by the steps of causing a chuck to hold the substrate such that the surface of a metal film or an insulating film of the substrate is caused to face upwards, pressing the surface of a polishing pad bonded to a joining plate pivotally borne by a spindle shaft having the axis arranged to be perpendicular to the substrate against the surface of the substrate while polishing solution is supplied to the boundary between the surfaces of the pad and the substrate, rotating the chuck holding the substrate and the polishing pad, and then reciprocating the polishing pad horizontally on the surface of the substrate so that at least a portion of the metal film or the insulating film is removed, the apparatus for chemimechanically polishing a substrate comprising a guide member disposed on the horizontal plane extended from the surface of the substrate held by the chuck and capable of supporting the surface of a portion of the polishing pad projecting over the outer surface of the substrate owing to swinging of the polishing pad on the substrate such that the guide member is provided independently from the chuck.

Since the surface of the portion of the polishing pad deviated over the outer end of the substrate is supported by the guide member, undesirable inclination of the spindle shaft can be prevented. Thus, a processed substrate exhibiting uniform thickness distribution can be obtained.

Since the guide member is secured independently from the rotative chuck, the surface area of the guide member can be reduced. As a result, wear of the polishing pad occurring due to the guide member can be prevented.

According to a second aspect of the invention, the apparatus has a structure that outer diameter r of the polishing pad is ½ to ¾ of diameter R of the substrate, and a range of reciprocative swinging of the polishing pad is 20 mm to 60 mm.

Since the diameter of the polishing pad is smaller than the diameter of the substrate, the reciprocating speed of the polishing pad and the number of change in the acceleration of reciprocating can be enlarged. Moreover, a state where the metal layer and the insulating layer of the substrate can visually be observed during the CMP process. In addition, measurement of the thickness of the substrate by using a laser sensor and observation of a state of polishing by using a color identifying sensor or a color identifying camera are permitted. As a result, detection of the end point of polishing can easily be performed.

According to a third aspect of the invention, the apparatus has a structure that the guide member incorporates a multiplicity of circular-arc grooves each having a width of 0.5 mm to 3 mm and a depth of 0.3 mm to 3 mm and formed at pitches of 1 mm to 5 mm.

Since the grooves with which the contact with the polishing pad is inhibited are provided for the guide member, the degree of wear of the polishing pad caused from the guide member can be reduced.

According to a fourth aspect of the invention, the apparatus has a structure that four chucks for holding the substrate are independently and rotatively provided for holes bored in an index table at the same intervals on a concentric circle of the axis of the index table, and the guide member is formed into a circular-arc shape which has a size capable of encircling ¼ to ½ of the circumference of each chuck, which is provided for each chuck such that the guide members are secured to the index table in a direction in which the polishing pad is reciprocating and which is disposed at point-symmetrical position making a rotational angle of 180° with respect to the axis of the index table.

Since the index-table type chemimechanical polishing apparatus is employed, the throughput time required to process the substrate can be shortened.

According to a fifth aspect of the invention, there is provided a process for chemimechanically polishing a substrate having a metal film layer on a surface of the substrate, the process comprising providing a polishing pad having a diameter shorter than a diameter of the substrate, and reciprocating the polishing pad on the surface of the substrate to polish the metal film layer of the substrate, wherein during the polishing of the substrate, a reciprocating velocity of the pad changes n times in a direction from a reciprocating start point which is near a center of the surface of the substrate, to a reciprocating end point which is apart from the center of the substrate, where n is an integer being 5-50, and wherein the metal layer of the substrate is polished repeating a cycle that the reciprocating velocity of the pad gradually increases up to a maximum speed, the reciprocating velocity gradually reduces after the reciprocating velocity reaches the maximum speed, then the reciprocating velocity of the pad gradually increases again up to a peak speed, and the reciprocating velocity gradually reduces after the reciprocating velocity reaches the peak speed.

According to a sixth aspect of the present invention, there is provided a process according to the fifth aspect of the present invention, wherein the diameter r of the polishing pad is ¾ of the diameter R of the substrate; and wherein the reciprocating velocity reaches the maximum speed while a center of the polishing pad is at a first region between (X+2L/9) and (X+3L/9), and the reciprocating velocity reaches the peak speed while the center of the polishing pad is at a second region between (X+8L/9) and (X+L), where X is the ¼ point of the radius of the substrate from the center of the substrate, and L is the reciprocation distance which is less than ¼R.

Furthermore, another objective of the present invention is to provide a method for manufacturing a semiconductor device which is capable of improving the yield based on an improved levelness of a wafer during a CMP process and which accordingly enables the production of a semiconductor device at a cost lower than those of methods of the prior an for manufacturing semiconductor devices as well as a low-cost semiconductor device.

The second embodiment of the present invention provides a substrate chemimechanical polishing device that is used for an operation, whereby a substrate is retained by a chuck while the metal film plane or insulating film plane of sold substrate faces upward, whereby the plane of a polishing pad try has been pasted onto an attachment panel, which is axially supported on a spindle axle, which possesses an axial core along a perpendicular direction, is pressed onto the surface of said substrate via a polishing agent, and whereby said metal film or said insulating film on the surface of said substrate is at least partially removed while said chuck, which retains said substrate, and said polishing pad are being induced to slide against one another and while said polishing pied is being induced to vacillate reciprocally along horizontal directions above said substrate.

A guide component supports the surface of the portion of the aforementioned polishing pad component which exceeds the outer circumference of said substrate as a result of the vacillation of said polishing pad above said substrate is configured above a horizontal plane on the extension of the surface of said substrate, which is being retained by the aforementioned chuck, in such a way that it will become integrated with said chuck slang the outer circumference of said chock.

Since the surface of the portion of the polishing pad which has come to exceed the outer circumference of the substrate can be supported by the guide component, the tilt of the polishing pad plane can be prevented, and a processed substrate with a favorable thickness distribution can be obtained.

The second embodiment of the present invention includes a substrate chemimechanical polishing device with mutually independent members of the aforementioned chuck configured in freely rotatable fashions within a certain number n (n, 2) of index table punchthrough holes which are configured on the concentric circle of the axial core while being positioned via an equal interval.

The substrate processing throughput time can be abbreviated by using a chemimechanical polishing device based on the index table format.

The substrate chemimechanical polishing device of the present invention preferably includes a guide component in the shape of a ring.

Even in a case where the guide component is rotated together with the chuck, the surface of the portion of the polishing pad component which has come to exceed the outer circumference of the substrate remains constantly supported by the ring-shaped guide component, based an which the tilt of the polishing pad plane can be prevented, and a processed substrate with a favorable thickness distribution can be obtained.

The substrate chemimechanical polishing device of the present invention preferably includes a channel through which the aforementioned polishing agent is discharged is formed on the lower plane of the aforementioned guide component.

Since polishing debris and an old polishing agent which has became unnecessary can be discharged through the discharge channel, the polishing rate can be stabilized.

The substrate chemimechanical polishing device according to the present invention further includes a vacant slot, through which is inserted the claw of a transportation robot that transports the aforementioned substrate, and which is configured between the inner circumference of the aforementioned guide component and the aforementioned chuck.

A transportation robot that possesses a claw that grips the outer circumference of a substrate can be used for substrate transportation purposes.

The substrate chemimechanical polishing device of the present invention preferably includes a vacant slot, through which is inserted the claw of a transportation robot that transports the aforementioned substrate, and which is configured on the inner circumference of the aforementioned guide component.

The present invention further provides a method for manufacturing a semiconductor device that includes a process whereby the surface of a semiconductor wafer is leveled by using the substrate chemimechanical polishing device described above.

Since the substrate chemimechanical polishing device described above is used, an excellent wafer levelness can be achieved during a CMP process, based on which the yield of the CMP process can be improved. The present invention is advantageous in that a semiconductor device can be manufactured at a cost lower than those of methods of the prior art for manufacturing semiconductor devices.

The present invention provides a semiconductor device that is manufactured by the method for manufacturing a semiconductor device described above, thereby providing a semiconductor device at a low cost.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendant advantages thereof will become readily apparent with reference to the following detailed description, particularly when considered in conjunction with the accompanying drawings, in which: [0053]
FIG. 1 is a plan view showing the relationship about the positions of an index table, chucks and guide members of a CMP apparatus according to the present invention; [0054]
FIG. 2 is a partial cross sectional view taken along line I-I shown in FIG. 1; [0055]
FIG. 3 is a side view showing the guide member when it is viewed from a direction II-II shown in FIG. 1; [0056]
FIG. 4 is a plan view showing the guide member; [0057]
FIG. 5 is a perspective view showing a known CMP apparatus; [0058]
FIG. 6 is a perspective view showing the polishing apparatus; [0059]
FIG. 7 is a cross sectional view showing the relationship about the positions of a polishing head and a conditioning mechanism; [0060]
FIG. 8 is a cross sectional view showing the polishing head; [0061]
FIG. 9 is a diagram showing the relationship about the positions of the substrate, the polishing pad and a swing start point; [0062]
FIG. 10 is a perspective view showing the polishing pad; [0063]
FIG. 11 is a graph showing a pattern of change in the reciprocating velocity of the polishing pad; [0064]
FIG. 12 is a diagram that shows a partial cross-sectional view of the I-I segment in FIG. 1, which pertains to a second embodiment of the present invention; [0065]
FIG. 13 is a diagram that shows a profile view of a guide component as it is viewed from the direction of II-II in FIG. 1, which pertains to the second embodiment of the present invention; [0066]
FIG. 14 is a diagram that shows a plane view of the guide component of the second embodiment of the present invention; and [0067]
FIG. 15 is a flow chart that shows the semiconductor device manufacturing processes of a third embodiment of the present invention.[0068]

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in detail with reference to the accompanying drawings. [0069]
FIG. 1 is a plan view showing an index table of a chemimechanical polishing apparatus incorporating four chucks. FIG. 2 is a cross sectional view taken along line I-I shown in FIG. 1. FIG. 3 is a partial side view showing the guide member when it is viewed from a direction II-II shown in FIG. 1. FIG. 4 is a plan view of the guide member. [0070]
As shown in FIG. 1, the index table [0071] 12 is divided into four zones, namely a substrate loading/unloading zone s1, a first polishing zone s2, a second polishing zone s3 and a third (final) polishing zone s4. The index table 12 is intermittently rotated at an angular degree of 90°.
[0072] Chucks 12 a, 12 b, 12 c and 12 d for holding the substrate are disposed at the same intervals on the concentric circle of the axis 12 e of the index table 12. The chucks 12 a, 12 b, 12 c and 12 d are independently and rotatively provided for holes 12 f bored in the index table.
Each of [0073] guide members 30 is formed into a circular-arc shape that has a size capable of encircling ¼ to ½ of the circumference of each chuck. Moreover, each of the guide members 30 is provided for each of the chucks 12 a, 12 b, 12 c and 12 d such that the guide members 30 are secured to the index table 12 (see FIG. 2) in a direction in which the polishing pad 4 is reciprocating. The guide members 30 provided for the corresponding chucks are disposed at point-symmetrical positions each making a rotational angle of 180° with respect to the axis 12 e of the index table.
The [0074] guide members 30 are disposed in the outer peripheries of the polishing pad 4 in a direction (indicated with an arrow shown in FIG. 1) in which the polishing pad is reciprocating. Since the index table 12 is rotated by each 90°, the guide members 30 are disposed in the zones s2, s2, s3 and s4 in the direction (shown with arrows) in which the polishing pad is reciprocating. Therefore, the guide members 30 are disposed at the point-symmetrical positions each making a rotational angle of 180° with respect to the axis 12 e of the index table. The guide members 30 may be bisectioned into guide members 30 a and 30 b as shown in FIG. 1.
The height of the surface of each of the [0075] guide members 30 is the same as the height of the surface of the substrate on the chuck. As an alternative to this, the height is a height obtained by subtracting the thickness (usually 1 mm to 10 mm in spite of variation according to the type of the layer) of the layer which is reduced by polishing from the height of the surface of the substrate.
A carrying [0076] robot 10 has a third arm 10 c and a sucking pad 10 d indicated with imaginary lines shown in FIG. 1. The third arm 10 c can be rotated around the axis O. A claw 10 e of the carrying robot can be inserted into a hollow 30 c of the guide member 30 a.
Referring to FIG. 2, [0077] reference numeral 40 represents a stationary frame for a ceramic porous chuck 12 a. Reference numeral 41 represents a pipe having two functions to serve an air supply pipe for applying/reducing the pressure of the ceramic porous chuck 12 a and a pipe for supplying cleaning solution.
The surface of the [0078] guide member 30 may be a flat surface having surface roughness of 0.1 mm or smaller. As an alternative to this, a multiplicity of circular-arc grooves 30 d each having a width of 0.5 mm to 3 mm and a depth of 0.3 mm to 3 mm and formed at pitches of 1 mm to 5 mm may be provided for the surface of the guide member 30. The guide member is made of aluminum, polyethylene fluoride or ceramics.
The [0079] polishing pad 4 is constituted by a hard urethane foam, a polyethylene fluoride sheet, an unwoven polyester fiber cloth, felt, an unwoven polyvinyl alcohol cloth, unwoven nylon fiber cloth or a material obtained by flow-casting urethane foam resin solution on the surface of the foregoing unwoven cloth, followed by foaming and hardening the flow-cast material.
The shape of the polishing pad is a disc shape, an annular shape or an elliptic shape. A pad having a thickness of 3 mm to 7 mm is bonded to an aluminum plate or a stainless steel plate. Specifically, it is preferable that an annular polishing pad shown in FIG. 10 is employed. The inner diameter Li of the bored portion of the annular polishing pad is 15% to 75% of the outer diameter Lo of the polishing pad, preferably 30% to 50%. The outer diameter r of the polishing pad with respect to the outer diameter R of the substrate w which must be polished is 0.55 time to 0.75 time. [0080]
The polishing solution is, for example, slurry containing (a) solid abrasive grains of colloidal alumina, fumed silica, cerium dioxide or titania by 0.01 wt % to 20 wt %; (b) oxidizer, such as copper nitrate, ferric citrate, manganese dioxide, ethylene diamine tetraacetate, hexacyanoferrate, hydrofluoric acid, fluorotitanate, diperosulfate, ammonium fluoride, hydrogen ammonium difluoride, ammonium fluoride or hydrogen peroxide by 1 wt % to 15 wt %; (c) surface active agent by 0.3 wt % to 3 wt %; (d) pH adjuster; and (e) preservative (see JP-A-6-313164; JP-A-8-197414; JP-Y-8-510437; JP-A-10-67986; and JP-A-10-226784). [0081]
The polisher slurry suitable for polishing metal, such as copper, copper-titanium, copper-tungsten and titanium-aluminum can be available from Fujimi, Rhodel Nitta, Cabot, U.S., Rhodel U.S. and Olin Arch. [0082]
It is preferable that the distance (L) for which the polishing pad is reciprocating or oscillating when the substrate is chemimechanically polished by using the chemimechanical polishing apparatus is 20 mm to 50 mm when a substrate having a diameter of 200 mm is polished and 20 mm to 60 mm when a substrate having a diameter of 300 mm is polished. [0083]
The reciprocation of the [0084] polishing pad 4 is as follows: a position of ⅛ point or ½ point (about 25 mm which is a ¼ point for a wafer having a diameter of 200 mm and a polishing pad having an outer diameter of 150 mm) of the radius of the substrate which is, by a ball screw, displaced from the central point O of the wafer to the left is a swing start point (Xo) for the polishing pad 4. A position displaced from the reciprocating start position to the left (toward the outer end of the wafer) for a distance of about 10 mm to 50 mm, preferable 20 mm to 40 mm is a reciprocating end point (Xe). The polishing pad 4 is reciprocatively swung in the lateral direction in the region having a length (L) between the reciprocating start point (Xo) and the reciprocating end point (Xe).
Preferred reciprocative swinging velocity of the polishing pad will now be described. When the velocity which is realized when the outer end of the polishing pad is present between the center of the substrate and the outer end is a reference velocity, the reciprocating velocity of the polishing pad is reduced in the central portion of the substrate. On the other hand, the reciprocating velocity of the polishing pad is raised. Thus, dishing can uniformly be performed. Moreover, it is preferable that the reciprocating velocity is appropriately changed n times (5 times to 30 times) when the diameter of the substrate is 200 mm. [0085]
When the diameter of the substrate is 300 mm, the range (L) of reciprocating is varied from 20 mm to 60 mm and the reciprocating velocity is appropriately changed 5 times to 50 times. [0086]
For example, where the substrate has a diameter of 200 mm and the velocity is changed 9 times in a region from the reciprocating start point (Xo=Po) which is deviated from the center of the wafer to the left for a distance of 25 mm to the reciprocating range (L) of 36 mm, the reciprocating velocity of the polishing pad is changed 9 times as shown in FIG. 11 in a period of movement from the reciprocating start point (Xo=Po) to the end (Xe=P[0087] 9) of reciprocating.
In a case shown in FIG. 11, the reciprocating velocity at the reciprocating start point (Xo=Po) is 0 mm/minute. The reciprocating velocity is gradually raised to the following velocities in the following regions: 400 mm/minute in a region from Po to a first change point (P[0088] 1); and the highest velocity of 3000 mm/minute in a region from P1 to a second change point (P2). The reciprocating velocity is gradually reduced as follows: 2000 mm/minute in a region from P2 to a third change point (P3); 1000 mm/minute in a region from P3 to a fourth change point (P4); 500 mm/minute in a region from P4 to a fifth change point (P5); and 100 mm/minute in a region from P5 to a sixth change point (P6). Then, the reciprocating velocity is raised as follows: 200 mm/minute in a region from P6 to a seventh change point (P7); and the height velocity of 2000 mm/minute in a region from P7 to an eighth change point (P8). Then, the reciprocating velocity is reduced in a region from P8 to a ninth change point (Xe=P9) which is the end point of reciprocating. Thus, the reciprocating velocity at the ninth change point (P9) is 0 mm/minute.
The position of Po on the substrate is 25 mm distant from the center of the substrate, P[0089] 1 is 29 mm distant from the center of the substrate, P2 is 33 mm distant from the center of the substrate, P3 is 37 mm distant from the center of the substrate, P4 is 41 mm distant from the center of the substrate, P5 is 45 mm distant from the center of the substrate, P6 is 49 mm distant from the center of the substrate, P7 is 53 mm distant from the center of the substrate, P8 is 57 mm distant from the center of the substrate, P9 which is the end point of swinging is 61 mm distant from the center of the substrate.
When the center of the polishing pad has moved to the end P[0090] 9 (Xe) of reciprocating and the reciprocating velocity is made to be 0 mm/minute, the reciprocating direction of the polishing pad is changed toward the central point O of the substrate. The polishing pad is returned to P8, P7, P6, P5, P4, P3, P2, P1 and the swing start point Po while the reciprocating velocity is being gradually changed to the corresponding point (2000 mm/minute, 200 mm/minute, 100 mm/minute, 500 mm/minute, 1000 mm/minute, 2000 mm/minute, 3000 mm/minute, 400 mm/minute and 0 mm/minute).
The reciprocating velocity, the number of change in the reciprocating velocity, the start and end points of reciprocating and the number of appearance of the peak velocity vary according to the type and the diameter of the substrate and the outer diameter of the polishing pad. Note that the change in the reciprocating velocity is made as described above such that the reciprocating velocity is 0 mm/minute from the swing start point Po to the end point Pn of reciprocating, the reciprocating velocity is gradually raised to the highest value, then the velocity is gradually reduced, the velocity is again gradually raised to the peak velocity, then the velocity is gradually reduced to 0 mm/minute. [0091]

Application Example 1

The substrate was a silicon substrate having a copper film formed on an insulating film having a diameter of 200 mm and constituted by silicon oxide. The polishing liquid was slurry (a reproduction material) for polishing copper film for a first step manufactured by Fujimi in a quantity of 75 ml/minute. The polishing pad was an annular pad formed by boring the central portion of a disc constituted by polyurethane resin (trade name IC1000) manufactured by Rhodel, U.S. and having an outer diameter of 150 mm to form a hole having a diameter of 50 mm. The polishing apparatus was an automatic chemimechanical polishing apparatus structured as shown in FIG. 1 and incorporating an index table, chucks, guide members and a polishing pad having three heads. The number of revolutions of the chuck table [0092] 12 a for chucking the substrate was 200 rpm in a reverse direction of the pad. The number of revolutions of the polishing pad was 400 rpm in the reverse direction of the chuck table. The pressure of the polishing pad which was applied to the substrate was 2.8 psi (200 g/cm²). The range of lateral reciprocating was 36 mm (the reciprocating start point was at a position 26 mm outwards distant from the center of the substrate). The reciprocating velocity was changed 9 times within the reciprocating range (L) as shown in FIG. 11. The chemimechanical polishing was performed for 60 seconds.
The copper removing rate was 7340 Å/minute, while the non-uniformity was 2.6%. [0093]

Comparative Example 1

The conditions according to Application Example 1 were changed in Comparative Example 1 such that the CMP apparatus (having no guide member) structured as shown in FIG. 5 was employed. The polishing pad was a disc-like pad constituted by polyurethane resin and having an outer diameter of 150 mm. The polishing pad was laterally reciprocating for a range of 54 mm (the reciprocating start point was 27 mm distant from the center of the substrate). The reciprocating velocity was not changed. Under the foregoing conditions, a copper-clad substrate was chemimechanically polished. [0094]
The copper removing rate was 3540 Å/minute, while the non-uniformity was 7.8%. [0095]
Similar results were obtained under the non-pervasion of a guide component under conditions otherwise identical to those in Application Example 1. [0096]
The chemimechanical polishing apparatus according to the present invention has the structure that the portion of the polishing pad deviated over the outer end of the substrate is supported by the guide members when the polishing pad is reciprocating. Therefore, inclination of the spindle shaft can be prevented. Hence it follows that a processed substrate exhibiting non-uniformity can be obtained. [0097]
The semiconductor device of the present invention is manufactured by the method of the present invention for manufacturing a semiconductor device. As a result, it becomes possible to manufacture a semiconductor device at a cost lower than those of the methods of the prior art for manufacturing semiconductor devices, and accordingly, an effect of lowering the cost for manufacturing a semiconductor device can be achieved. [0098]
Next, the substrate chemimechanical polishing device of the second application embodiment of the present invention will be explained with reference to FIGS. 12 through 14. [0099]
The constitution of the guide component of the second embodiment differs from its counterpart of the first application example, but since the constitution of the remainder is identical to its counterpart of the first application embodiment, overlapping explanations of identical components will be avoided. FIG. 12 is a diagram equivalent to FIG. 2 for the first embodiment (I-I cross sectional view in FIG. 1), FIG. 13 is a diagram equivalent to FIG. 3 for the first application example (partial profile view of the guide component as it is viewed from the II-II direction in FIG. 1), and FIG. 14 is a diagram that shows a plane view of the guide component. [0100]
As far as the second embodiment is concerned, the [0101] guide component 50 is characterized by the shape of a ring, and it is configured along the outer circumference of the chuck 12 a in a coaxial fashion vis-a-vis the chuck 12 a. The guide component 50 is fixed to the guide component attachment platform 51 via a bolt, whereas the guide component attachment platform 51 is fixed to the fixation platform 40 via the belt, and the guide component 50 is configured to be integrated with the chuck 12 a under their co-pervasion. The guide component attachment platform 51 is characterized by a shape which covers the opening of the index table 12 for preventing the entry of a polishing agent into the rotational mechanical unit, etc. of the chuck 12 a.
The [0102] guide component 50 is configured to be integrated with the chuck 12 a in the second embodiment, and since the substrate and guide component 50 become rotated together during a polishing operation, it is desirable for the guide component 50 to be characterized by the shape of a ring which can totally surround the outer circumference of the substrate rather than by the partial shape shown in FIG. 3. In such a case, the guide component 50 can constantly support a polishing pad portion which has come to exceed the substrate even in a case where the position of the chuck 12 a varies due to rotation.
The [0103] channels 52, through which a polishing agent is discharged, furthermore, are formed at four positions on the plane of the guide component 50 that is contacted with the guide component attachment platform 51 (i.e., lower plane of the guide component 50) for the purpose of discharging the polishing agent remaining in. a region surrounded by the guide component 50, guide component attachment platform 51, and the chuck 12 a.
It is desirable, furthermore, for the guide [0104] component attachment platform 51 to be positioned as closely as possible to the outer circumferential position of the substrate from the standpoint of sufficiently securing the effect of supporting the polisher portion which has come to exceed the substrate during the polishing operation, but at the same time, it is desirable to secure a vacant slot into which the claw of the transportation robot can be inserted. It is necessary, therefore, to secure at least a vacant slot which is necessary for the insertion of the claw of the transportation robot. For this reason, it is desirable for the dimensions of the vacant slot, which is necessary for the insertion of the claw of the transportation robot, to be designated in such a way that it can be secured between the outer circumference of the substrate and the inner circumference of the guide component or, as reference numeral 30 c in FIG. 4 indicates, for the inner circumference of the guide component to be partially notched for securing such a vacant slot which is necessary for the insertion of the claw.
As in the case of the [0105] guide component 30 of the first embodiment, furthermore, the surface height of the guide component 50 of the second embodiment may be identical to the surface height of the substrate above the chuck, or the height may be designated to be equivalent to a differential obtained by subtracting a margin corresponding to the thickness of the layer to be polished and removed (normally 1˜10 μm, although it differs depending on the types of layers) from the surface height of the substrate.
Incidentally, it is desirable for the outer diameter of the polishing pad to be confined to a range of ½-{fraction (9/10)} of the diameter of the substrate with regard to both the first and second application embodiments, and more favorable results are obtained in a case where the outer diameter of the polishing pad is confined to a range of ½-¾ of the diameter of the substrate. [0106]
Next, the method of the present invention for manufacturing a semiconductor device will be explained with reference to FIG. 15, which represents a third application embodiment of the present invention [0107]
FIG. 15 is a flow chart which shows a semiconductor device manufacturing processes. At the “start” stage of such a semiconductor device manufacturing scheme, proper treatment processes are selected from among steps S[0108] 201 through S204, which will be mentioned below, at step S200. An advancement is made to any of steps S201 through S204 depending on the selection.
Step S[0109] 201 represents as oxidation process whereby the surface of a wafer is oxidized. Step S202 represents a CVD process whereby an insulating film is formed on the wafer surface by means of CVD, etc. Step S203 represents an electrode formation process whereby an electrode is formed above the wafer by means of deposition, etc. Step S204 represents an ion implantation process whereby an ion is implanted into the wafer.
Upon the completion of the CVD process or electrode formation process, an advancement is made to step S[0110] 205. Step S205 represents a CMP process. During this CMP process, an interlayer insulating film may be leveled by using the polishing device of the present invention, or a damascene pattern may instead be formed by polishing the metal film on the surface of the semiconductor device, etc.
Upon the completion of the CMP process or oxidation process, an advancement is made to step S[0111] 206. Step S206 represents a photolithographic process. During this photolithographic process, procedures for coating a resist on the wafer, for printing a circuit pattern onto the wafer by means of exposure under the pervasion of an exposure device, and for developing the exposed wafer are carried out. Step S207, which follows it next, represents an etching process whereby segments other than the developed resist image are etched and removed, whereby the resist is subsequently peeled, and whereby the resist residue which has become unnecessary upon the completion of etching is removed.
Next, it is judged at step S[0112] 208 whether or not all the necessary processes have been completed, and in case where a yet-to-be-completed process(es) remains, step S200 is resumed, and a circuit pattern is formed on the wafer by repeating the aforementioned steps. An “end” is declared in a case where all the processes are judged to have been completed at step S208.
As far as the method of the present invention for manufacturing a semiconductor device is concerned, the chemimechanical polishing device of the present invention is used during a CMP process, and since an excellent wafer levelness can be achieved during the CMP process, the yield of the CMP process can be improved. As a result, an effect of manufacturing a semiconductor device at a cost lower than those of the methods of the prior art for manufacturing semiconductor devices can be achieved. [0113]
Incidentally, the polishing device of the present invention may also be applied to the CMP process of a semiconductor device manufacturing scheme other than the aforementioned semiconductor device manufacturing scheme. [0114]
The semiconductor device of the present invention is manufactured by the method of the present invention for manufacturing a semiconductor device. As a result, it becomes possible to manufacture a semiconductor device at a cost lower than those of the methods of the prior art for manufacturing semiconductor devices, and accordingly, an effect of lowering the cost for manufacturing a semiconductor device can be achieved. [0115]
It should be noted that the exemplary embodiments depicted and described herein set forth the preferred embodiments of the present invention, and are not meant to limit the scope of the claims hereto in any way. [0116]
Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. [0117]

Claims

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. An apparatus for chemimechanically polishing a substrate having a metal film layer and an insulating film layer, the apparatus comprising:

a chuck adapted to hold the substrate, wherein the metal film layer or the insulating film layer of the substrate faces upward;

a spindle shaft having an axis arranged to be perpendicular to the substrate;

a joining plate pivotally disposed by the spindle shaft;

a polishing pad bonded to the joining plate, the polishing pad having a surface pressed onto a surface of the substrate; and

a guide member having an upper surface, wherein the upper surface is almost the same in height as the surface of the substrate, the guide member for supporting a part of the surface of the polishing pad projecting over an outer peripheral edge of the substrate due to movement of the polishing pad on the substrate, the guide member provided independently from the chuck, wherein the chuck and the polishing pad rotate, and the polishing pad is reciprocated in a direction, whereby at least a portion of the metal film layer or the insulating film layer is removed.

2. The apparatus as claimed in claim 1, wherein an outer diameter r of the polishing pad is ½ to ¾ of a diameter R of the substrate.

3. The apparatus as claimed in claim 1, wherein the guide member comprises a plurality of circular-arc grooves each having a width of 0.5 mm to 3 mm and a depth of 0.3 mm to 3 mm and formed at pitches of 1 mm to 5 mm.

4. The apparatus as claimed in claim 1, further comprising an index table defining four holes at same intervals on a concentric circle of an axis of the index table,

wherein the chuck comprises four chucks independently and rotatively provided in the four holes;

the guide member is formed into a circular-arc shape having a size capable of encircling ¼ to ½ of the circumference of each of the four chucks;

the guide member is provided for each of the four chucks; and

each of the guide members is disposed to the index table in a direction in which the polishing pad moves and at point-symmetrical position making a rotational angle of 180° with respect to the axis of the index table.

5. The apparatus as claimed in claim 1, wherein the guide member has a shape of a ring.

6. The apparatus as claimed in claim 1, wherein a channel through which a polishing agent is discharged is formed on a lower plane of the guide member.

7. The apparatus as claimed in claim 1, wherein a vacant slot through which a claw of a transportation robot which transports the substrate is inserted is configured between an inner circumference of the guide member and the chuck.

8. The apparatus as claimed in claim 1, wherein a vacant slot through which a claw of a transportation robot which transports the substrate is inserted is configured on an inner circumference of the guide member.

9. The apparatus as claimed in claim 1, wherein an outer diameter r of the polishing pad is ½ to {fraction (9/10)} of a diameter R of the substrate.

10. An apparatus for chemimechanically polishing a substrate having a metal film layer and an insulating film layer, the apparatus comprising:

a spindle shaft having an axis arranged to be perpendicular to the substrate;

a joining plate pivotally disposed by the spindle shaft;

a guide component which supports the surface of a portion of the polishing pad which has come to exceed an outer circumference of the substrate as a result of vacillation of the polishing pad above the substrate is configured above a horizontal plane on an extension of the surface of said substrate, which is being retained by the chuck, in such a way that it will become integrated with the chuck along an outer circumference of the chuck,

wherein the chuck and the polishing pad rotate, and the polishing pad is reciprocated in a direction, whereby at least a portion of the metal film layer or the insulating film layer is removed.

11. The apparatus as claimed in claim 10, wherein mutually independent members of the chuck are configured in freely rotatable fashions within a certain number of index table punchthrough holes which are configured on a concentric circle of an axial core while being positioned via an equal interval.

12. The apparatus as claimed in claim 10, wherein the guide component has a shape of a ring.

13. The apparatus as claimed in claim 10, wherein an outer diameter r of the polishing pad is ½ to ¾ of a diameter R of the substrate.

14. The apparatus as claimed in claim 10, wherein the guide member comprises a plurality of circular-arc grooves each having a width of 0.5 mm to 3 mm and a depth of 0.3 mm to 3 mm and formed at pitches of 1 mm to 5 mm.

15. The apparatus as claimed in claim 10, wherein a channel through which a polishing agent is discharged is formed on a lower plane of the guide component.

16. The apparatus as claimed in claim 10, wherein a vacant slot through which a claw of a transportation robot which transports the substrate is inserted is configured between an inner circumference of the guide component and the chuck.

17. The apparatus as claimed in claim 10, wherein a vacant slot through which a claw of a transportation robot which transports the substrate is inserted is configured on an inner circumference of the guide component.

18. The apparatus as claimed in claim 10, wherein an outer diameter r of the polishing pad is ½ to {fraction (9/10)} of a diameter R of the substrate.

19. A method for manufacturing a semiconductor device, comprising the step of leveling a surface of a semiconductor wafer by using the apparatus for chemimechanical polishing a substrate claimed in any one of claims 1 through 18.

20. A semiconductor device manufactured by the method for manufacturing a semiconductor device claimed in claim 19.

21. A process for chemimechanically polishing a substrate having a metal film layer on a surface of the substrate, the process comprising the steps of:

providing a polishing pad having a diameter shorter than a diameter of the substrate; and

reciprocating the polishing pad on the surface of the substrate to polish the metal film layer of the substrate,

wherein during the polishing of the substrate, a reciprocating velocity of the polishing pad changes n times in a direction from a reciprocating start point which is near a center of the surface of the substrate, to a reciprocating end point which is apart from the center of the substrate, where n is an integer between 5 and 50; and

wherein the metal layer of the substrate is polished repeating a cycle that the reciprocating velocity of the pad gradually increases up to a maximum speed, the reciprocating velocity gradually reduces after the reciprocating velocity reaches the maximum speed, then the reciprocating velocity of the pad gradually increases again up to a peak speed, and the reciprocating velocity gradually reduces after the reciprocating velocity reaches the peak speed.

22. The process as claimed in claim 21, wherein:

the diameter r of the polishing pad is ¾ of the diameter R of the substrate; and

the reciprocating velocity reaches the maximum speed while a center of the polishing pad is at a first region between (X+2L/9) and (X+3L/9), and the reciprocating velocity reaches the peak speed while the center of the polishing pad is at a second region between (X+8L/9) and (X+L), where X is the ¼ point of a radius of the substrate from the center of the substrate, and L is a reciprocation distance which is less than ¼R.