JP2001308049A - Method of compensating shifting velocity of a processing means in processing of board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of times of trial and error for deciding the optimum shifting velocity, for the shifting velocity of a processing means being performed, based on experience. SOLUTION: In a processing method, which removes a part of the surface of a substrate by changing a shifting speed αi of the processing speed at reciprocation of a polishing pad on a substrate by (n) times (n is a positive number of 5-50, and i=n), (1) the processing of a substrate is finished at a desired speed αi in advance, and the thickness distribution of the substrate in the direction of a straight line passing the center point of the substrate is measured, and (2) the thickness distribution state from the center point of the substrate to one end is separated into the components of (n) modes by the harmonic analysis with a computer, and the thickness distribution is approximated to the profile of the periodic function (i is the number of modes, ai and bi are amplitudes of modes i, the mode is the wave whose wavelength is the value being obtained by dividing the distance from the center point of the substrate to one end of the substrate by natural number, and is the same value as the natural number) of a period 2Π, and (3) the shifting speed αi of each i-th processing member is compensated, based on the amplitude of the wavelength of each mode i.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reciprocating a grinding wheel or a polishing pad having a diameter smaller than the diameter of a substrate linearly on the substrate and excellent in thickness distribution in the width direction of the substrate. The present invention relates to a method of obtaining or correcting a n-times acceleration when grinding or polishing a substrate while changing the one-way speed when the processing means moves on the substrate to obtain the substrate n times.

[0002] The present invention relates to the removal of a metal film formed on an insulating layer of a substrate, the removal of an insulating layer film on the surface of a substrate having an insulating layer film formed on a pattern of a metal film, the STI ( Shallow
Trench Insulator) P-TEOS layer removal, etc.
Alternatively, it is useful for grinding a bare wafer. That is, a constant thickness distribution, for example, for a ground substrate, the thickness amplitude is 1 μm
In addition, a processing method capable of providing a substrate satisfying a market requirement of 0.5 μm or less for a CMP device wafer can be realized.

[0003]

2. Description of the Related Art A polishing pad mounted on a spindle shaft is used. A polishing slurry is supplied to the surface of the polishing pad while a substrate held by a chuck is pressed against the polishing pad to rotate the pad and the substrate in the same direction or in the opposite direction. While sliding, and
2. Description of the Related Art A chemical mechanical polishing apparatus that reciprocates (oscillates) a polishing pad in one direction on a substrate and performs chemical mechanical polishing (CMP polishing) on the substrate is known (Japanese Patent Application Laid-Open No. 10-303152;
JP-A-11-156711, Patent No. 2968784
No. 2,331,948). 5 to 8 show the chemical mechanical polishing apparatus.

FIG. 5 is a perspective view showing an example of a chemical mechanical polishing apparatus, FIG. 6 is a perspective view showing a polishing pad transfer mechanism, and FIG.
Is a partial cross-sectional view of the polishing pad and the conditioning device,
FIG. 8 is a sectional view of the polishing head.

In the index type chemical mechanical polishing apparatus 1 shown in FIGS. 5, 6 and 7, reference numeral 2 denotes a polishing head, 2a
Is a polishing head for rough polishing, 2b is a head for finish polishing, 3,
3 is a rotating shaft, 3a is a motor, 3b is a gear, and 3c is a gear.
Re, 3d is a gear, 4, 4 is a polishing pad, 5, 5 is a pad conditioning mechanism, 5a is a dressing disk, 5b is an injection nozzle, 5c is a protective cover, 6, 6 is a rotatable cleaning brush, 7 is Polishing head transfer mechanism, 7a
Is a rail, 7b is a feed screw, and 7c is a moving body screwed to the feed screw and has a polishing head 2. 7d and 7e are gears, 7f is a motor, 8 is an air cylinder which is a head elevating mechanism, 9 is a wafer w storage cassette, and 10 is a low.
Robot 11 for transferring wafers, 11 is a temporary wafer mounting table, 12 is a rotatable wafer chuck mechanism 12a, 12b, which is provided at equal intervals on the same circumference with a shaft 12e as an axis.
An index table having 12c and 12d,
The bull 12 is classified into a wafer loading zone of s1, a rough polishing zone of s2, a finishing polishing zone of s3, and a wafer unloading zone of s4.

Reference numeral 13 denotes an unloading transfer robot; 14a, a chuck dresser; 14b, a chuck cleaning mechanism; 15, a temporary wafer mounting table; 16, a belt conveyor;
Reference numeral 7 denotes a wafer cleaning mechanism.

In the polishing head 2 shown in FIG. 8, the overhanging edge 21a of the substrate 21 has a pressure cylinder-20.
The polishing pad (annular polishing cloth) 4 is supported by a substrate 21 via a polishing cloth mounting plate 22. A diaphragm 23 is stretched in a pressurizing chamber 20b in the pressurizing cylinder 20, and compressed air is press-fitted into the pressurizing chamber 20b through the spindle shaft 3, and the substrate 21 is three-dimensionally (X, Y) by the pressure. , Z), and the pad 4 is held parallel to the wafer surface.

A polishing liquid or cleaning liquid supply pipe 24 is provided at the center of the head 2, and the tip of the pipe faces the back surface of the polishing pad ring body avoiding the center hollow portion 4 a of the polishing pad.
A polishing liquid or an etching liquid is supplied to the surface of the metal layer of the substrate via the annular body.

The step of polishing a wafer (substrate) having a metal film on an insulating layer using the chemical mechanical polishing apparatus 1 is performed as follows. 1) The wafer w1 is taken out of the cassette 9 by the arm of the transfer robot 10, placed on the temporary mounting table 11 with the metal film surface facing upward, the back surface thereof is cleaned, and then the index table 12 is transferred by the transfer robot. Uehara-
It is transferred to the ding zone s1 and is sucked by the chuck mechanism 12a.

2) Rotate the index table 12 clockwise by 90 degrees to move the wafer w1 to the first polishing zone s.
2, the spindle shaft 3 is lowered, the polishing pad 4 attached to the head 2a is pressed against the wafer w1, and the wafer is chemically and mechanically polished by rotating the spindle shaft 3 and the chuck mechanism. During this time, a new wafer w
2 is placed on the temporary table, transferred to the wafer loading zone s1, and sucked by the chuck mechanism 12b. At the time of CMP processing of the wafer, the abrasive liquid is applied to the back surface of the annular body 4 through the supply pipe 24 provided in the hollow portion of the spindle shaft 3.
It is supplied at a rate of 100 ml / min. The number of rotations of the wafer adsorbed on the chuck table is 200 to 800 rpm.
m, preferably 200 to 600 rpm, and the rotation speed of the polishing pad is 400 to 3000 rpm, preferably 400 to 1
000 rpm and the pressure on the substrate is 1.2-3 psi.

During the CMP process, the polishing pad 4 is ball screwed to the left of the center point O of the wafer at an 8th or 2nd point of the radius of the substrate (for a 200 mm diameter wafer and a 150 mm outer diameter polishing pad, A position (about 25 mm of the quarter point) is defined as a movement start point (Xo), and a width of about 10 to 50 mm, preferably 20 to 50 mm leftward (toward the outer periphery of the wafer) from the start point position.
The position of 40 mm is defined as the movement regression point (Xe), and the distance (L) between them is reciprocated in the left-right direction (X-axis direction) (see FIG. 9).

When the chemical mechanical polishing in the first polishing zone s2 has been performed for a desired time, the spindle shaft 3 is raised and retracted rightward, and guided to the pad cleaning mechanism 5, where high-pressure jet water is jetted. Abrasive particles and metal polishing debris attached to the front pad surface are removed by the rotating brush 5 while spraying from the polishing pad 5b, and the polishing pad is transported to the right again.
Wait on top.

3) The index table is rotated clockwise by 90 degrees, the polished wafer w1 is guided to the second polishing zone s3, and the spindle shaft 3 is moved down so that the head 2
The polishing pad 4 attached to the wafer b is pressed against the roughly polished wafer w1, and the spindle mechanical shaft and the chuck mechanism are rotated to perform the chemical mechanical finish polishing of the wafer.
After finishing polishing, the spindle shaft 3 is raised and retracted to the right, the polishing pad attached to the head 2b is cleaned by the cleaning mechanism 5, and transferred to the right again, and the second polishing zone is moved.
On standby s3. During this time, a new wafer w3 is placed on the temporary mounting table, transferred to the wafer loading zone s1, and sucked by the chuck mechanism 12c. In the first polishing zone s2, the chemical mechanical rough polishing of the wafer w2 is performed.

4) The index table 12 is rotated 90 degrees clockwise to guide the polished wafer w1 to the unloading zone s4. Next, the wafer polished and finished by the unloading transfer robot 13 is placed on the temporary table 1.
5 and after cleaning the back surface, further transfer robot 13
The cleaning liquid is sprayed from a nozzle 17 onto the polished wafer pattern surface to clean the wafer, and the wafer is further guided to the next step. During this time,
A new wafer w4 is placed on the temporary table, and the wafer
It is transferred to the ding zone s1 and is sucked by the chuck mechanism 12d. In the first polishing zone s2, the chemical mechanical rough polishing of the wafer w3 is performed, and in the second polishing zone s3, the chemical mechanical finish polishing of the wafer w2 is performed.

5) The index table 12 is rotated 90 degrees clockwise, and the same operations as the above-mentioned steps 2) to 4) are repeated to perform chemical mechanical polishing of the wafer.

In the above example, the chemical mechanical polishing is divided into two stages of the first rough polishing and the second finish polishing in order to shorten the throughput time. However, the CMP process may be performed in one stage. Alternatively, rough polishing, medium finish polishing, and finish polishing are divided into three stages to further reduce the throughput time. When a three-step CMP process is performed, s1 is used as a wafer loading and unloading zone.
S2 is the first polishing zone, and s3 is the second polishing zone.
And s4 is a third polishing zone (an example of a CMP apparatus shown in FIG. 1 described later).

The material of the polishing pad may be different from that of the first polishing pad and the second polishing pad. The abrasive slurry may also vary.

The substrate is held on a chuck table with the surface of the metal film or the surface of the insulating layer (including the surface where both are mixed) facing upward, and is mounted on a spindle shaft having a vertical axis with respect to the substrate. The surface of the polishing pad attached to the attached mounting plate is pressed via loose polishing abrasive grains (abrasive)), the substrate and the polishing pad are rotated and slid, and the polishing pad smaller in diameter than the substrate is reciprocated. In the chemical mechanical polishing method by moving and removing at least a part of the metal film or the insulating film on the substrate surface, to obtain a substrate having a good thickness distribution in the width direction of the substrate due to the small diameter of the polishing pad, This is more difficult than a conventional method in which a substrate held by a top ring is pressed against a polishing platen having a larger diameter, and both the substrate and the platen are rotated and slid to perform chemical mechanical polishing.

Therefore, there has been proposed a method of obtaining a substrate having a good thickness distribution by changing the moving speed of the small-diameter polishing pad on the substrate n times (US Sematec 1999 November General Assembly). The moving speed of the small-diameter polishing pad on the substrate (changed by changing the acceleration or deceleration n times) is empirically determined based on the position of the polishing pad on the substrate and the area at which the polishing pad contacts the substrate. The speed is estimated and the number of changes and the magnitude of the speed are obtained through trial and error. Therefore,
There is a drawback that the number of trial and error for finding the optimum condition is large.

[0020]

SUMMARY OF THE INVENTION The present invention provides a method of processing a substrate using a processing means having a diameter smaller than the diameter of the substrate and reciprocating the processing means. It is an object of the present invention to provide a method of correcting a speed that can be performed.

[0021]

A first aspect of the present invention is to use a processing means selected from a grinding wheel or a polishing pad having a diameter smaller than the diameter of a substrate, holding the substrate on a chuck, and holding the substrate on the substrate. On the other hand, the processing means supported by a spindle shaft having a shaft center in a vertical direction is pressed between the substrate and the processing means via a grinding liquid or an abrasive liquid, and the chuck for holding the substrate and the processing means are rotationally slid. And a movement start point (Xo) and a movement return point (Xo), in which the processing means is reciprocated between straight lines passing through the center point of the substrate in the horizontal direction on the substrate.
n times (n moving speeds alpha _i therebetween processing means when the distance (L) reciprocates between e) is a positive number of 5 to 50.)
A method of correcting a moving speed α _i of a processing means in a processing method of removing a part of a substrate surface by changing, characterized by the following:

Processing of the substrate is completed at a desired speed α _i in advance, and the thickness distribution of the substrate in a linear direction passing through the center point of the substrate is measured. The thickness distribution from the center point of the substrate to the edge of one substrate is subjected to harmonic analysis using a computer, separated into n-mode components, and the thickness distribution is calculated as a periodic function having a period of 2П.

(Equation 2) (Where, i is mode - the number of de, a _i and b _i are motor - is the amplitude of the de i, mode - the de obtained by dividing the distance from the center point of the substrate to the edge of one of the substrates a natural number A wave whose value is a wavelength
It has the same value as the natural number. ) Is approximated. The moving speed α _i of each i-th processing means is corrected based on the amplitude of the wavelength of each mode _i .

The method of the present invention has an advantage that the number of wasted test substrates is reduced because the number of trial and error is reduced, as compared with the conventional method in which trial and error is performed in a dark cloud.

According to a second aspect of the present invention, the movement acceleration of the processing means is defined as a reference speed when the outer periphery of the processing means is located between the center point and the outer circumference of the substrate. It is characterized in that the speed is reduced and the moving speed of the processing means is increased in the outer peripheral portion of the substrate.

From the area of the processing means in contact with the substrate,
Since the contact area is large at the center point of the substrate, that is, the area to be processed is large, a long processing time is required, and the processing area is short at the outer peripheral portion of the substrate, so that the processing time is short.

According to a third aspect of the present invention, in the correction,
When the average thickness of the desired substrate is T _o , the average thickness of the substrate obtained by processing at the moving speed α _i is T, and the thickness distribution of this substrate is approximated to a profile of a periodic function having a period of 2П. each mode - when the amplitude of the wavelength of the de i was W _i, correction of the moving speed alpha _i of the processing means, when the _{T ≧ T o, α i =} α i
x (1−W _i / T _o ), and when T <T _o , α _i =
It is characterized in that it is corrected to α _ix (1 + W _i / T _o ).

Since the thickness amplitude is extremely small with respect to the average thickness T, even if the n-th speed correction is forcibly determined to be the amplitude of the n-th mode, the substrate obtained by the processing after the correction is processed. Thickness fluctuations are well within the range of market requirements.

According to a fourth aspect of the present invention, the outer diameter r of the processing means is 1/2 to 3/4 of the diameter R of the substrate, and the reciprocating width of the processing means is 20 to 60 mm. . By making the diameter of the processing means smaller than the diameter of the substrate, the moving speed of the processing means and the number of changes in the speed can be increased.
In addition, during processing, for example, during CMP polishing, the polishing state of the metal layer and the insulating layer of the substrate can be visually observed, and the thickness of the substrate can be measured with a laser sensor, a color identification sensor, a color
The polishing state can be observed with the identification camera, and the end point of polishing can be easily detected.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 shows the chuck of the chemical mechanical polishing apparatus
FIG. 2 is a sectional view taken along the line II in FIG. 1, FIG. 3 is a partial side view of the guide member viewed from the II-II direction in FIG. 1, and FIG. 4 is a line III in FIG. Cross-sectional view of the substrate edge polishing tool viewed from the -III direction,
FIG. 12 is a plan view of an index table provided with four chucks of a chemical mechanical polishing apparatus according to another embodiment.

In FIG. 1, the index table 12
Is a substrate loading / unloading zone s1,
The first polishing zone s2, the second polishing zone s3, and the third polishing zone s4 are instructed to rotate intermittently by 90 degrees. Chucks 12a and 12 for holding a substrate
The b, 12c, and 12d are provided at equal intervals on the concentric circle of the axis of the index table 12, and each of the four b, 12c, and 12d is independently rotatably provided in a hole 12f formed by hollowing the index table. The guide member 30 has an arc shape having a size that surrounds 1/4 to 1/2 of the outer circumference of the chuck, and has an index tee in a direction in which the polishing pad 4 swings for each of the chucks 12a, 12b, 12c, and 12d. Bull 12
(See FIG. 2) The guide members 30, 30, 30, 30 provided fixed to each chuck and provided for each chuck are provided at point contrast positions rotated by 180 degrees with respect to the axis of the index table. Can be

The guide member 30 is provided on the outer periphery of the chuck in the direction of movement of the polishing pad (the direction of the arrow in FIG. 1). Since the index table 12 is rotated by 90 degrees, the guide member 30 exists in the direction of movement of the polishing pad in each of the zones s1, s2, s3, and s4.
Reference numerals 30, 30, and 30 are provided at point-symmetric positions rotated by 180 degrees with respect to the axis of the index table. The guide member 30 may be divided into two parts 30a and 30b as shown in FIG. The surface height of the guide member 30 is the same as the surface height of the substrate on the chuck or the thickness of the layer to be polished and removed from the surface height of the substrate.
10 to 10 μm).

The third arm 10c and the suction pad 10d of the transfer robot 10 are indicated by phantom lines in FIG.
c is configured to be rotatable about the axis O. The claw 10e of the transfer robot can be inserted into the space 30c of the guide member 30a. The substrate end polishing tool 50 is provided on an index table 12 base as shown in an enlarged view in FIG. 4, and a shaft 52 rotatably provided by bearings 51, 51.
A disc-shaped fixing tool 53 is attached to the upper end of the fixing tool, and a felt or grindstone 53a is provided on the surface of the fixing tool. The polishing surface 53 of the substrate edge polishing tool 50 is rotated by the rotation of the substrate w.
The fixing tool 53 provided with a rotates together. Polished surface 53
a may be provided with a Japanese drum-shaped groove wider than the thickness of the substrate.

In FIG. 2, reference numeral 40 denotes a fixing base for the ceramic porous chuck 12a, and reference numeral 41 denotes a pipe which also serves as an air supply pipe for depressurizing or pressurizing the ceramic porous chuck 12a and a cleaning liquid supply pipe. Guide member 30
May be flat with a surface roughness of 0.1 μm or less, or arc-shaped grooves 30d, 30d, 30d having a width of 0.5 to 3 mm and a depth of 0.3 to 3 mm may have a pitch interval of 1 to 5 mm. A large number may be provided for each. The guide member is formed using aluminum, polyfluoroethylene, ceramics or the like as a material.

Examples of the polishing pad material include hard urethane sheet, polyfluoroethylene sheet, polyester fiber non-woven fabric, felt, polyvinyl alcohol fiber non-woven fabric, nylon fiber non-woven fabric, and foamable urethane resin solution on these non-woven fabrics. What is cast, then foamed and cured is used. As the pad shape, a disk shape, a donut shape, or an elliptical shape is used, and the thickness is 3 to 7 mm.
Is used by being attached to a mounting plate such as an aluminum plate or a stainless steel plate. Preferably, an annular polishing pad shown in FIG. 10 is used. The hollow inner diameter li of the annular polishing pad is 15 to 75 times the length of the polishing pad outer diameter lo.
%, Preferably 30 to 50%. Substrate w to be polished
The outer diameter r of the polishing pad with respect to the outer diameter R of
It is 0.75 times.

The polishing liquid is (a) colloidal alumina,
0.01-20% by weight of solid abrasive grains such as fumed silica, cerium oxide, titania, and (b) copper nitrate, iron citrate,
1 to 15% by weight of an oxidizing agent such as manganese peroxide, ethylenediaminetetraacetic acid, hexacyanoiron, hydrofluoric acid, fluorotitanic acid, dipersulfate, ammonium fluoride, ammonium hydrogen difluoride, ammonium persulfate, hydrogen peroxide, etc. (C) 0.3 to 3% by weight of a surfactant,
A slurry containing (d) a pH adjuster, (e) a preservative, and the like is used (JP-A-6-313164, JP-A-8-197414, JP-A-8-51037, and JP-A-10-104). 67986, JP-A-10-226784, etc.). Abrasive slurries suitable for polishing metals such as copper, copper-titanium, copper-tungsten, and titanium-aluminum are available from Fujimi Incorporated Co., Ltd., Roder Nitta Co., Ltd., Cabot Corporation in the United States, Available from Olin Arch Inc., USA.

The moving distance (L) of the polishing pad when the substrate is chemically and mechanically polished using the chemical and mechanical polishing apparatus is 200 m.
Preferably, the substrate has a diameter of 20 to 50 mm for a substrate having an m diameter, and 20 to 60 mm for a substrate having a diameter of 300 mm. The polishing pad 4 can be moved linearly in the horizontal direction by rotating the polishing pad 4 with a ball screw to the left of the center point O of the wafer at an 8th or 2nd point of the radius of the substrate. In the case of a pad, a position of about 25 mm of the quarter point) is set as a movement start point (Xo), and a width of about 10 to 50 mm, preferably 20 to 40 m, leftward (toward the outer periphery of the wafer) from the start point position.
m is defined as a regression point (Xe), and a distance (L) therebetween.
To reciprocate.

The reciprocating movement of the polishing pad is defined as a reference speed when the outer periphery of the polishing pad is located between the center point and the outer periphery of the substrate. The moving speed (acceleration) of the polishing pad is increased so that dishing is performed uniformly, and the moving speed is set to n when the diameter of the substrate is 200 mm.
It is preferable to make a change for increasing or decreasing the number of times (5 to 30 times). When the diameter of the substrate is 300 mm, the moving width (L) is changed to 20 to 60 mm and the moving speed is changed to 9 to 50 times to temporarily increase or decrease.

For example, in the case of a substrate having a diameter of 200 mm, when the movement start point (Xo = Po) is 25 mm to the left of the center point of the wafer and the movement width (L) reaches 36 mm, and the acceleration changes nine times, From the starting point (Xo = Po) to the regression point (Xo
During the movement up to e = P ₉ ), the acceleration of the polishing pad is changed nine times as shown in FIG.

In FIG. 11, the movement start point (Xo = P
The moving speed in o) is 0 mm / min, and from Po to the first conversion point (P1), the moving speed is 400 mm / min.
The maximum speed of 30 from 1 to the second conversion point (P2)
The speed is temporarily increased to be 00 mm / min, and the speed is 2000 mm / min from P2 to the third conversion point (P3).
Speed 1000mm from to the fourth conversion point (P4)
/ Min, speed 5 from P4 to the fifth conversion point (P5)
00 mm / min, the speed temporarily decreased to 100 mm / min from P5 to the sixth conversion point (P6), and increased to 200 mm / min from P6 to the seventh conversion point (P7).
Min, the peak speed reaches 2000 mm / min from P7 to the eighth conversion point (P8), and then decelerates from P8 to the ninth regression point (Xe = P9). The moving speed is changed so that the moving speed at the conversion point (P9) is 0 mm / min.

The position of Po on the substrate is two points from the center of the substrate.
5 mm, P1 is 29 mm from the substrate center point, P2 is 33 mm from the substrate center point, P3 is 37 mm from the substrate center point, P3
4 is 41 mm from the substrate center point, and P5 is 4 mm from the substrate center point.
5 mm, P6 is 49 mm from the substrate center point, P7 is 53 mm from the substrate center point, P8 is 57 mm from the substrate center point, and P9 of the regression point is 61 mm from the substrate center point. When the polishing pad reaches the regression point P9 (Xe) and the speed becomes 0 mm / min, the moving direction of the polishing pad is changed to the direction of the center point O of the substrate, and P8, P7, P6, P5, P
4, P3, P2, P1 and the movement start point Po at the respective positions (2000 mm / min, 200
mm / min, 100 mm / min, 500 mm / min, 1000
mm / min, 2000 mm / min, 3000 mm / min, 40
(0 mm / min, 0 mm / min).

The moving speed, the number of changes in the moving speed, the moving start point position, the regression point position, and the number of appearances of the peak speed depend on the type and diameter of the substrate used, the outer diameter of the processing means, and the like. However, in order to change the movement speed, the speed is changed from the movement start point Po to the regression point P.
It is unified that the pattern tends to decelerate temporarily when the speed increases from 0 mm / min to the maximum speed toward n, and then temporarily increases the speed, the peak speed, and temporarily decreases again to 0 mm / min. You.

As another embodiment of the polishing apparatus, as shown in FIG. 12, a substrate end polishing tool 50 is provided, but an index table 12 having no guide may be used. Further, the fixture of the substrate end polishing tool 50 may be structured to be driven by a motor.

Reference Example: A silicon substrate provided with a copper film on a silicon oxide insulating film having a diameter of 200 mm as a substrate, and a slurry for polishing a copper film for the first step by Fujimi Incorporated as a polishing agent (prototype) A 75 mm / min. Polishing pad, a circular pad of 150 mm in outer diameter made of a polyurethane resin (trade name: IC1000) made by U.S.
As the polishing apparatus, an automatic chemical mechanical polishing apparatus having an index table, a chuck, a guide member, a substrate end polishing tool and a three-head polishing pad shown in FIG. 1 was used, and the rotation speed of the substrate chuck table was set to 200 rpm in a counterclockwise direction. The rotation speed of the polishing pad is 400 rpm clockwise, and the pressure of the polishing pad applied to the substrate is 2.8 psi (200 g / cm ² ).
The lateral movement width is 36 mm (the movement start point is 26 mm outside diameter from the substrate center point), and the movement speed is changed nine times within one movement width (L) as shown in FIG. Thickness distribution (average thickness 19
(0.1 μm) are two points out of the 256 measurement points that do not fall within 0.5 μm of the fluctuation width with respect to the average thickness, which are 190.7 μm and 190.8 μm. 2 μm) on the same circumference.

These two points and the center point of the wafer (190.2 μm)
The thickness distribution of the substrate on the straight line including
m) to the right end (190.0 μm) as follows (unit: μm). 189.8 190.2 190.7 190.3 189.7 190.2 190.0 190.2 190.1 189.8 190.0 190.2 190.6 190.3 190.0

In the CMP polishing pattern shown in FIG.
Since it is out of the point and the swing width, the speed is corrected. The thickness distribution state from the left end to the center point of the wafer is subjected to harmonic analysis (Fourier analysis) using a computer, and is separated into n (here, 9) mode components. Periodic function with period 2П

(Equation 3) (Where, i is mode - the number of de, a _i and b _i are motor - is the amplitude of the de i, mode - the de obtained by dividing the distance from the center point of the substrate to the edge of one of the substrates a natural number A wave whose value is a wavelength
It has the same value as the natural number. ) Is approximated.

FIG. 13 is a diagram showing a state of thickness distribution from the left end of the wafer to the center point. Assuming that the width from the left end to the center point is the total width t, for example, if mode n = 9,
The thickness distribution in FIG. 13 is represented by a (wavelength t) in FIG.
B (wavelength t / 2), c (wavelength t / 4) in FIG. 14, FIG.
4 (wavelength t / 8) (not shown) and i (wavelength t / 256; not shown) in FIG.
The computer calculates the amplitude Wi of the wavelength in the harmonic analysis in each mode _i .

[0047] Each mode obtained while approximating the thickness distribution of the substrate to the profile of the periodic function of period 2P - when the amplitude of the wavelength of the de i was W _i, the correction of the movement acceleration alpha _i of the processing means T when the ≧ T _o, and the corrected _{α i = α i x (1} -W i / T o), when the _{T <T o, α i =} α i x (1 + W i / T o)
Is corrected. In the CMP polishing example of FIG. 13, the average thickness (T) of the obtained substrate is 190.1 μm, which is slightly larger than the desired average thickness (T _o ) of the substrate.
Therefore, the next CMP polishing speed is the speed α _i = α _i x
_{(1-W i / T o} ) and so as to computer - receiving a commander of motor control unit, to correct the software.

[0048]

Example 1 In the chemical mechanical polishing in Reference Example 1, the thickness distribution (average thickness: 190.1 μm) of the CMP polishing wafer obtained by correcting the above-mentioned speed was the average thickness among the 256 measurement points. Where the runout width within 0.5 μm is not 0
Was a point.

The thickness distribution of the substrate on the straight line including the center point (190.1 μm) of the wafer is from the left end (190.1 μm) to the right end (190.1 μm).
0.0 μm) as follows (unit: μm). 190.1 190.0 190.3 190.1 189.9 189.8 190.0 190.1 190.1 189.8 189.8 190.0 190.2 190.1 190.0 Copper removal rate was 7600 Å / min and non-uniformity was 2.2%.

The method for correcting the moving speed of the polishing pad according to the present invention can of course be applied to a grinding method using a grinding wheel having a smaller diameter than the substrate diameter.

The method of correcting the moving speed of the processing means of the present invention can reduce the number of trial and error for determining the optimum moving speed with respect to the moving speed of the processing means based on experience.

[Brief description of the drawings]

FIG. 1 is a plan view showing a positional relationship between an index table, a chuck, and a guide member of a CMP apparatus.

FIG. 2 is a partial sectional view taken along a line II in FIG.

FIG. 3 is a side view of the guide member viewed from the II-II direction in FIG.

FIG. 4 is a partial cross-sectional view of the substrate edge polishing tool taken along the line III-III in FIG.

FIG. 5 is a perspective view of a CMP apparatus according to another embodiment.

FIG. 6 is a perspective view of a polishing apparatus.

FIG. 7 is a sectional view showing a positional relationship between a polishing head and a conditioning mechanism.

FIG. 8 is a sectional view of a polishing head.

FIG. 9 is a diagram illustrating a positional relationship between a substrate and a movement start point of a polishing pad.

FIG. 10 is a perspective view of a polishing pad.

FIG. 11 is a diagram showing a change pattern of a moving speed of a polishing pad.

FIG. 12 is a plan view of an index table used in a chemical mechanical polishing apparatus showing another embodiment.

FIG. 13 shows a thickness distribution (half) of a substrate polished by CMP.
It is shown.

FIG. 14 is a diagram showing wavelengths of thickness fluctuation width divided into nine modes by harmonic analysis.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chemical mechanical polishing apparatus w Substrate L Movement width 2 Polishing head 3 Spindle shaft 4 Polishing pad 7 Polishing head transfer mechanism 8 Polishing head elevating mechanism 12 Index table 12a, 12b, 12c, 12d Chuck 30 Guide member 50 Substrate end polishing tool

Claims (4)

[Claims] A substrate is held on a chuck by using a processing means selected from a grinding wheel or a polishing pad having a diameter smaller than the diameter of the substrate, and a spindle shaft having a vertical axis with respect to the substrate is provided. The pressed processing means is pressed between the substrate and the processing means via a grinding liquid or an abrasive liquid, and the chuck holding the substrate and the processing means are rotated and slid, and the processing means is placed on the substrate. When reciprocating a distance (L) between a movement start point (Xo) reciprocating on a straight line passing through a center point of the base and a regression point (Xe) in the horizontal direction, a moving speed of the processing means during the reciprocation the alpha _i n times (n is .i = n a positive number of 5 to 50) a method of correcting the movement speed alpha _i of the processing means in a processing method for removing a portion of the altered allowed by the substrate surface, following wherein the of: terminating the processing of the substrate in advance at the desired speed alpha _i , Measuring the thickness distribution in the linear direction of the substrate passing through the center point of the substrate. The thickness distribution state from the center point of the substrate to the edge of one of the substrates is subjected to harmonic analysis using a computer, separated into n-mode components, and the thickness distribution is calculated as a periodic function having a period of 2П. ] (Where, i is mode - the number of de, a _i and b _i are motor - is the amplitude of the de i, mode - the de obtained by dividing the distance from the center point of the substrate to the edge of one of the substrates a natural number A wave whose value is a wavelength
It has the same value as the natural number. ) Is approximated. The moving speed α _i of each i-th processing means is corrected based on the amplitude of the wavelength of each mode _i . 2. The moving speed of the processing means is defined as a reference speed when the outer periphery of the processing means is located between the center point and the outer circumference of the substrate. The method according to claim 1, wherein the moving speed of the processing means is increased in the section. 3. The average thickness of a substrate obtained by processing at a moving speed α _i is defined as T _o, and the average thickness of a desired substrate is defined as T _o .
Each mode when the thickness distribution of the substrate is approximated to the profile of the periodic function of period 2P - when the amplitude of the wavelength of the de i was W _i, correction of the moving speed alpha _i of the processing means, T ≧ T _o when the, and the corrected _{α i = α i x (1} -W i / T o), when the T <T _o, to be corrected with the _{α i = α i x (1} + W i / T o) 2. The method according to claim 1, wherein the moving speed of the processing means is corrected. 4. The outer diameter r of the processing means is 1/1 / the diameter R of the substrate.
And the reciprocating width of the processing means is 20 to 60.
2. The method according to claim 1, wherein the moving speed is mm.