JP3086437B2 - Chemical mechanical polishing apparatus and chemical mechanical polishing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical mechanical polishing apparatus and a chemical mechanical polishing method used as a planarization technique in a multi-layer wiring process or an element isolation process of a semiconductor integrated circuit.

[0002]

2. Description of the Related Art In recent years, chemical mechanical polishing has attracted attention as a flattening technique in a manufacturing process of a semiconductor integrated circuit which has been miniaturized. The reason is that the use of chemical mechanical polishing makes it possible to planarize the entire surface of the substrate, which could not be obtained by other planarization techniques such as the resist etch-back method. Problems such as a decrease in the reliability of the wiring formed on the surface can be solved.

[0003] A conventional chemical mechanical polishing apparatus and a conventional chemical mechanical polishing method disclosed in Japanese Patent Application Laid-Open No. H8-339979 will be described below with reference to FIGS.

As shown in FIGS. 8 and 9, a conventional chemical mechanical polishing apparatus includes a polishing platen 10 rotatably provided.
And a polishing pad 11 fixed on the polishing platen 10.
A substrate holding head 13 for holding a wafer 12 as a substrate to be polished and pressing a surface to be polished of the held wafer 12 against a polishing pad 11; an abrasive supply pipe 15 for supplying an abrasive 14 onto the polishing pad 11 A ring-shaped seal member 16 provided on a peripheral portion of a lower surface of the substrate holding head 13, and a ring-shaped guide member 17 provided on the lower surface of the substrate holding head 13 and outside the seal member 16. . Inside the substrate holding head 13, a space 18 formed by the wafer 12 placed on the substrate holding head 13, the sealing member 16, and the polishing pad 11.
Is provided with a pressurized gas supply passage 19 for supplying a pressurized gas.

Hereinafter, a chemical mechanical polishing method performed by using the conventional chemical mechanical polishing apparatus will be described.

First, an abrasive 14 is supplied from an abrasive supply pipe 15 onto the polishing pad 11 while rotating the polishing platen 10 to rotate the polishing pad 11. After holding the wafer 12 on the substrate holding head 13 such that the surface to be polished of the wafer 12 faces the polishing pad 11, the substrate holding head 13 is lowered, and the pressure is applied from the pressurized gas supply path 19 to the space 18. The wafer 1 is supplied by supplying gas and pressurized gas.
The surface to be polished of the wafer 12 is chemically and mechanically polished by pressing the surface to be polished 2 against the polishing pad 11. Here, in one polishing step, one wafer 1
The case where the chemical mechanical polishing is performed on the wafer 2 is shown. However, when the chemical mechanical polishing is performed on a plurality of wafers 12 in one polishing step, a plurality of substrate holding heads 13 are provided.

On the polished surface of the wafer 12 which has been subjected to the chemical mechanical polishing, the abrasive grains contained in the abrasive 14 and the polished film or shavings of the polishing pad 11 adhere as foreign matters. If foreign matter adheres to the surface to be polished of the wafer 12, problems such as contamination of the inside of the manufacturing apparatus in which the post-process is performed with the foreign matter and reduction in product yield occur.

Therefore, when the chemical mechanical polishing of the surface to be polished of the wafer 12 is completed, the substrate holding head 13 holding the wafer 12 is moved above the cleaning pad on which the brush is implanted on the surface. A cleaning agent such as hydrofluoric acid or ammonia is supplied onto the
Is lowered to press the polished surface of the wafer 12 against the cleaning pad, thereby performing scrub cleaning on the polished surface of the wafer 12.

However, if the scrub cleaning with the cleaning liquid is performed for a long time using a high concentration cleaning liquid, micro scratches (micro defects) are enlarged on the surface to be polished of the wafer 12 and wiring defects occur, so that the product is defective. Therefore, it is not preferable to perform a long-time scrub cleaning with a high-concentration cleaning solution because the yield decreases and the throughput decreases.

Therefore, recently, in the chemical mechanical polishing step, when the chemical mechanical polishing of the wafer 12 is completed,
Pure water is supplied from the polishing agent supply pipe 15 to the polishing pad 11 in place of the polishing agent to press the surface to be polished of the wafer 12 against the polishing pad 11, thereby cleaning the surface to be polished of the wafer 12 with pure water. There has been proposed a method of removing foreign matter attached to a surface to be polished by using the method. In the cleaning step using pure water, the pressing force of the substrate holding head 13 against the polishing pad 11, the rotation speed of the polishing platen 10, the cleaning time, the amount of pure water, the temperature of pure water, and the like are controlled. 1
The foreign matter adhering to the surface to be polished 2 is mechanically removed.

[0011]

By the way, when cleaning with pure water in the polishing step and scrub cleaning with the cleaning liquid in the cleaning step are performed, foreign matter adhering to the polished surface (surface) of the wafer 12 is reliably removed.

However, in the polishing step, the polishing agent 14 supplied onto the polishing pad 11 enters the back surface of the wafer 12 from between the wafer 12 and the sealing member 16, so that the polishing agent 14 is also applied to the back surface of the wafer 12. The abrasive grains contained in the agent 14 and the shavings of the film to be polished or the polishing pad 11 adhere as foreign matters.

As described above, if the scrub cleaning is performed over a long period of time using a high-concentration cleaning solution in the cleaning process, there arises a problem that the product yield decreases and the throughput decreases. In this case, it is not preferable to perform a long-time scrub cleaning with a high-concentration cleaning solution, so that foreign substances adhering to the back surface of the wafer 12 cannot be reliably removed. In particular, as shown in FIG. 9, the surface to be polished of the wafer 12 is polished by the pressurized gas supplied from the pressurized gas supply passage 19 to the space portion 18.
When pressed against the wafer, the foreign matter is dried by the pressurized gas and adheres to the back surface of the wafer 12, so that it is extremely difficult to remove the foreign matter.

If foreign matter remains on the back surface of the wafer, there arises a problem that the inside of a manufacturing apparatus in which a post-process is performed is contaminated by the foreign matter. Also, since foreign particles are aggregated on the back surface of the wafer to form secondary particles, the surface to be polished of the wafer is not perpendicular to the optical axis of the exposure light in the photolithography process, resulting in defocus. When the wafer is pressed against the polishing pad via the pressing film in the subsequent chemical mechanical polishing step, the portion of the wafer where the secondary particles are formed is strongly pressed by the pressing film, so that the polishing is uniform. The problem of not being performed occurs.

In view of the above, an object of the present invention is to prevent foreign matter from remaining on the back surface of a substrate to be polished made of a wafer in a polishing step of chemical mechanical polishing.

[0016]

Means for Solving the Problems To achieve the above object, a solution taken by the present invention is to clean the back surface of a substrate to be polished after the polishing step by using cleaning water or an abrasive containing no abrasive grains. This is to prevent drying of the back surface of the substrate to be polished by supplying cleaning water or an abrasive containing no abrasive grains to the back surface of the substrate to be polished during the polishing process.

A first chemical mechanical polishing apparatus according to the present invention comprises: a polishing surface plate rotatably provided; a polishing pad fixed on the polishing surface plate; Abrasive supply means for supplying to the polishing pad, cleaning water supply means for supplying cleaning water onto the polishing pad, a substrate holding head for holding the substrate to be polished detachably and pressing the held substrate to the polishing pad, Reversing means for reversing the substrate to be polished upside down.

According to the first chemical mechanical polishing apparatus, since the reversing means for reversing the substrate to be polished is provided, the substrate to be polished after the polishing step can be reversed on the polishing pad. In addition, since the cleaning water supply means for supplying the cleaning water onto the polishing pad is provided, the cleaning water is supplied onto the polishing pad after the polishing step, and the back surface of the substrate to be polished is pressed against the polishing pad by the substrate holding head. Thus, the back surface of the substrate to be polished can be cleaned.

A second chemical mechanical polishing apparatus according to the present invention comprises a rotatable polishing plate, a polishing pad fixed on the polishing plate, and a rotatable cleaning device. Surface plate, a cleaning pad provided on the cleaning surface plate, an abrasive supply means for supplying an abrasive on the polishing pad, and a cleaning water supply means for supplying cleaning water on the cleaning pad. A substrate holding head movably provided between the upper side of the polishing pad and the upper side of the cleaning pad, for detachably holding the substrate to be polished and for individually pressing the held substrate to the polishing pad and the cleaning pad. And a reversing unit for reversing the substrate to be polished.

According to the second chemical mechanical polishing apparatus, the substrate holding head is provided so as to be movable between above the polishing pad and above the cleaning pad, so that the substrate to be polished after the polishing step is polished. It can be moved from above the pad onto the cleaning pad. Further, since the reversing means for reversing the substrate to be polished is provided, the substrate to be polished after the polishing step can be placed on the cleaning pad with the surface upside down. Further, since a cleaning water supply means for supplying the cleaning water onto the cleaning pad is provided, the cleaning water is supplied onto the cleaning pad after the polishing step, and the back surface of the substrate to be polished is pressed against the cleaning pad by the substrate holding head. Thus, the back surface of the substrate to be polished can be cleaned.

A third chemical mechanical polishing apparatus according to the present invention comprises a rotatable polishing plate, a polishing pad fixed on the polishing plate, and a detachable substrate. A substrate holding head for holding and holding the held substrate to be polished against a polishing pad, first abrasive supply means for supplying a first abrasive containing abrasive grains on the polishing pad, and a substrate holding head And a second abrasive supply means for supplying a second abrasive containing no abrasive particles to the back surface of the substrate to be polished held by the polishing apparatus.

According to the third chemical mechanical polishing apparatus, since the second polishing agent supply means for supplying the second polishing agent containing no abrasive to the back surface of the substrate to be polished is provided, the polishing step Since the second polishing agent can be supplied to the back surface of the substrate to be polished in the above, the foreign matter attached to the back surface of the substrate to be polished in the polishing step can be prevented from drying and sticking to the back surface.

It is preferable that the third chemical mechanical polishing apparatus further includes a cleaning water supply means for supplying cleaning water to the back surface of the substrate to be polished held by the substrate holding head.

In the third chemical mechanical polishing apparatus, the substrate holding head presses the substrate to be polished against the polishing pad by supplying a pressurized gas to the back side of the substrate to be polished held by the substrate holding head. It is preferable to have a substrate pressing means.

A first chemical mechanical polishing method according to the present invention comprises a polishing step of polishing the surface of a substrate to be polished while supplying an abrasive onto a polishing pad; And a cleaning step of cleaning the back surface of the substrate to be polished while supplying cleaning water onto the polishing pad.

According to the first chemical mechanical polishing method, the back side of the substrate to be polished is turned upside down, and the back surface of the substrate to be polished is cleaned while supplying cleaning water onto the polishing pad. In the polishing step, foreign substances adhering to the back surface of the substrate to be polished can be reliably removed.

According to a second chemical mechanical polishing method of the present invention, a polishing agent is supplied onto a rotating polishing pad and the surface of the substrate is pressed against the rotating polishing pad. A polishing step of polishing the substrate, a transfer step of transferring the substrate to be polished after the polishing step is turned over to a cleaning pad, supplying cleaning water onto the cleaning pad and polishing the cleaning pad. A cleaning step of cleaning the back surface of the substrate to be polished by pressing the back surface of the substrate.

According to the second chemical mechanical polishing method, the substrate to be polished after the polishing step is transferred onto the cleaning pad in a state where the substrate is turned upside down, and then the cleaning water is supplied onto the cleaning pad. Since the back surface of the substrate to be polished is cleaned, foreign substances attached to the back surface of the substrate to be polished in the polishing step can be reliably removed.

In the third chemical mechanical polishing method, a polishing agent is supplied onto a polishing pad and the substrate to be polished is pressed from a back surface thereof onto a rotating polishing pad via a pressing film, whereby the polishing of the substrate to be polished is performed. A polishing step of polishing the front surface, cleaning water is supplied between the substrate to be polished and the pressing film, and the back surface of the substrate to be polished is cleaned by bringing the back surface of the substrate to be polished into sliding contact with the pressing film. A washing step.

According to the third chemical mechanical polishing method, washing water is supplied between the substrate to be polished and the pressing film after the polishing step, and the back surface of the substrate to be polished is brought into sliding contact with the pressing film. Accordingly, since the back surface of the substrate to be polished is cleaned, foreign substances adhering to the back surface of the substrate to be polished in the polishing step can be reliably removed.

In the fourth chemical mechanical polishing method according to the present invention, the surface of the substrate to be polished is polished by supplying an abrasive onto the polishing pad and pressing the surface of the substrate to be polished against the rotating polishing pad. Assuming a chemical mechanical polishing method provided with a polishing step, the polishing step includes a step of supplying a cleaning liquid to the back surface of the substrate to be polished whose surface is polished.

According to the fourth chemical mechanical polishing method, the cleaning liquid is supplied to the back surface of the polished substrate whose surface is polished in the polishing process, so that the foreign substances adhering to the back surface of the polished substrate in the polishing process are dried. Can be prevented from sticking to the back side.

In the fifth chemical mechanical polishing method according to the present invention, a polishing agent is supplied onto a polishing pad and the surface of the substrate is polished by pressing the surface of the substrate against a rotating polishing pad. Assuming a chemical mechanical polishing method including a polishing step, the polishing step includes a step of supplying an abrasive containing no abrasive grains to the back surface of the substrate to be polished whose surface is polished.

According to the fifth chemical mechanical polishing method, an abrasive containing no abrasive is supplied to the back surface of the substrate whose surface is polished in the polishing step. It is possible to prevent the foreign matter adhering to the back surface from drying and sticking to the back surface. In this case, since the abrasive supplied to the back surface of the substrate to be polished does not contain abrasive grains, it is possible to avoid a situation in which new foreign matter adheres to the back surface of the substrate to be polished.

In the fourth or fifth chemical mechanical polishing method, the polishing step preferably includes a step of pressing the substrate to be polished against the polishing pad by supplying a pressurized gas to the back side of the substrate to be polished.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A chemical mechanical polishing apparatus and a chemical mechanical polishing method according to a first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows the overall configuration of a chemical mechanical polishing apparatus 100 according to the first embodiment. In the chemical mechanical polishing apparatus 100, a wafer cassette containing wafers as substrates to be polished is arranged. A load station 101 having a load robot for taking out a wafer from a wafer cassette and transferring the wafer, and a wafer cassette for storing a polished wafer and an unload robot for storing the polished wafer in the wafer cassette And an unload station 102 having

On the right side of the loading station 101 and the unloading station 102, a rotatable wafer standby plate 103 is provided. As shown in FIG. Four wafer mounting tables 104A, 10A
4B, 104C, and 104D are provided. A first wafer reversing robot 105 having a pair of arms 105a approaching and moving away from each other is disposed on the right rear side of the wafer standby board 103.
A second wafer reversing robot 106 having a pair of arms 106a approaching and separating from each other is disposed on the right front of the robot 03. The first and second wafer reversing robots 105 and 106 Table 104A-10
The wafer 120 placed on the 4D is moved to the arms 105a and 10a.
6a, the held wafer 120 is turned upside down and mounted again on the wafer mounting tables 104A to 104D.

As shown in FIG. 1, a first cleaning plate 10 rotatably provided on the right side of the wafer standby plate 103.
The seventh and second cleaning platens 108 are arranged in the front-rear direction, and the first and second cleaning platens 107 and 108 are arranged.
A polishing platen 109 rotatably provided is disposed on the right side of the table. Note that only one of the first cleaning platen 107 and the second cleaning platen 108 may be provided, and in that case, the first wafer reversing robot 105
And only one of the second wafer reversing robots 106 may be provided.

As shown in FIG. 3, the first cleaning platen 10
A cleaning pad 110 on which a brush is implanted is fixed on the seventh and second cleaning platens 108, and a polishing pad 112 made of an elastic material is fixed on the polishing platen 109. Above the cleaning pad 110 and the polishing pad 112, a substrate holding head 114 that holds the wafer 120 and presses the held wafer 120 against the cleaning pad 110 or the polishing pad 112 is movably arranged. A cleaning water supply pipe 115 for supplying cleaning water (pure water) onto the cleaning pad 110 is provided above the cleaning pad 110, and a polishing pad 112 is provided above the polishing pad 112. A liquid supply pipe 116 for supplying an abrasive or cleaning water (pure water) is provided on the top of the liquid supply pipe 116. The upper end of the liquid supply pipe 116 is connected to an abrasive supply source via a flow path switching valve (three-way valve) 117. 118 and a washing water supply source 119.

Further, as shown in FIG. 1, the chemical mechanical polishing apparatus 100 straddles the wafer standby plate 103, the first and second cleaning platens 107 and 108, and the polishing platen 109. In this state, a transfer table 113 that moves in the left-right direction by a rack and pinion mechanism is provided, and the transfer table 113 has a holding unit that detachably holds the substrate holding head 114.

(Chemical Mechanical Polishing Method Performed Using Chemical Mechanical Polishing Apparatus According to First Embodiment) Hereinafter, a chemical mechanical polishing method performed using the chemical mechanical polishing apparatus according to the first embodiment will be described. explain.

First, the first wafer is taken out of the wafer cassette placed on the load station 101, and the first wafer is taken out.
After placing the wafer on the wafer mounting table 104A, the wafer standby plate 103 is rotated counterclockwise by 90 degrees, then the second wafer is taken out from the wafer cassette, and the second wafer is mounted on the wafer mounting table 104B. Place.

Next, the wafer stand board 103 is rotated counterclockwise by 180 degrees to move the wafer mounting tables 104A and 104B to the right side of the wafer stand board 103, and the transfer table 113 holding the substrate holding head 114. Is moved to the first stop position A, the substrate holding head 114 is lowered, and the wafers mounted on the wafer mounting tables 104A and 104B are vacuum-adsorbed and held on the substrate holding head 114.

Next, after moving the transfer table 113 to the third stop position C, the flow path switching valve 117 is controlled to connect the abrasive supply source 118 and the liquid supply pipe 116, and the abrasive is The surface of the wafer 120 is supplied with an abrasive by supplying the liquid from the supply source 118 onto the polishing pad 112 via the liquid supply pipe 116 and lowering the substrate holding head 114 to press the wafer 120 against the rotating polishing pad 112. Grind.

When the surface of the wafer 120 is being polished,
The third and fourth wafers are sequentially taken out from the wafer cassette, and the taken-out third and fourth wafers are placed on the wafer mounting table 1.
The substrates are sequentially placed on 04C and 104D. In addition, the wafer mounting table 1
When a wafer is placed on 04C, 104D,
The wafers mounted on the wafer mounting tables 104C and 104D are stored in a wafer cassette arranged in the unload station 102 in advance.

Next, when the polishing of the surface of the wafer 120 by the polishing agent is completed, the flow switching valve 117 is controlled to connect the cleaning water supply source 119 to the liquid supply pipe 116, and the cleaning water is supplied to the cleaning water supply source. The liquid is supplied from 119 to the polishing pad 112 via the liquid supply pipe 116, and the surface of the wafer 120 is cleaned with cleaning water.

When the cleaning of the surface of the wafer 120 with the cleaning water is completed, the substrate holding head 114 is raised, and the transfer table 113 is moved to the first stop position A. Thereafter, the substrate holding head 114 is lowered, and the wafer 120 held by the substrate holding head 114 is mounted on the wafer mounting table 104A (104B).

Next, the first wafer reversing robot 105 is driven to reverse the front and back of the wafer 120 mounted on the wafer mounting table 104A (104B). That is, as shown in FIG. 4A, the wafer mounting table 104A (104
After raising B), as shown in FIG. 4B, the wafer 1 mounted on the wafer mounting table 104A (104B)
20 is the arm 105 of the first wafer reversing robot 105
a, and then, as shown in FIG. 4C, the arm 105a is rotated to turn the arm 105a upside down, and then the wafer 12 held by the arm 105a is turned upside down.
0 is mounted on the wafer mounting table 104A (104B) again. Thereby, the front and back of the wafer 120 are reversed. still,
When reversing the front and back of the wafer 120, the transfer table 113 is used.
Is the second stop position B or the third stop position C so as not to hinder the operation of the first wafer reversing robot 105.
Evacuation.

When the wafer 120 is turned upside down, the transfer table 113 holding the substrate holding head 114 is moved to the first stop position A, and then the substrate holding head 114 is moved down to the wafer mounting table 104A (104B). The placed wafer 120 is held by the substrate holding head 114. Next, after moving the transfer table 113 to the second stop position B, cleaning water is supplied from the cleaning water supply pipe 115 onto the cleaning pad 110, and the wafer 120 is rotated by lowering the substrate holding head 114. By pressing against the cleaning pad 110, the back surface of the wafer 120 is cleaned with cleaning water. In this way, in the polishing step, the wafer 120
The foreign substances adhering to the back surface are removed by the washing water. In the cleaning step using the cleaning water, the substrate holding head 114
Pressure on the cleaning pad 110 and the cleaning platen 107
By controlling the rotation speed, cleaning time, amount of cleaning water, temperature of cleaning water, and the like in (108), foreign substances adhering to the back surface of the wafer 120 are mechanically removed.

By the way, after the surface is polished by the polishing agent, the surface of the wafer 120 cleaned by the cleaning water is:
Preferably, it is transferred onto the cleaning pad 110 without drying. By doing so, the foreign substances adhering to the back surface of the wafer 120 are aggregated to form secondary particles and do not stick, so that the foreign substances adhering to the back surface of the wafer 120 can be easily removed by the cleaning water.

In the first embodiment, the back surface of the wafer 120 is cleaned by pressing the wafer 120 whose surface is turned upside down against the cleaning pad 110. Alternatively, the back surface of the wafer 120 whose surface is turned upside down is replaced with this. May be again pressed against the polishing pad 112 to clean the back surface of the wafer 120 with the cleaning water supplied from the cleaning water supply source 119.

When the cleaning of the back surface of the wafer 120 is completed, the substrate holding head 114 is moved up, the transfer table 113 is moved to the first stop position A, and then the substrate holding head 114 is lowered. The wafer 120 held in the wafer mounting table 104A (1
04B), and then the wafer mounting table 104A (1
04B) is housed in a wafer cassette arranged in the unload station 102.

(Second Embodiment) Hereinafter, a chemical mechanical polishing apparatus and a chemical mechanical polishing method according to a second embodiment of the present invention will be described with reference to FIGS.

FIG. 5 shows an overall configuration of a chemical mechanical polishing apparatus 200 according to the second embodiment, and FIG. 6 shows a cross-sectional structure of a main part of the chemical mechanical polishing apparatus 200 according to the second embodiment. I have.

The chemical mechanical polishing apparatus 200 holds a rotatable polishing platen 201, a polishing pad 202 fixed on the polishing platen 201, and a wafer 203 as a substrate to be polished. And held wafer 203
Substrate holding head 204 for pressing the surface to be polished against polishing pad 202, and first polishing agent supply pipe 20 for supplying first polishing agent 205 containing abrasive grains onto polishing pad 202.
6, a ring-shaped guide member 207 provided on the periphery of the lower surface of the substrate holding head 204, and the substrate holding head 20
4 and a pressing film 208 provided inside the guide member 207 on the lower surface of the guide member 207.

A fluid supply path 210 is provided inside the substrate holding head 204. At the upper end of the fluid supply path 210, there is provided a second flow path opening / closing valve 211 having no abrasive grains.
From the second abrasive supply source 212 storing the second abrasive
The other end of the second abrasive supply pipe 213 for supplying the abrasive is opened, and the cleaning water is supplied from a cleaning water supply source 215 that has a flow path opening / closing valve 214 and stores the cleaning water such as pure water. The other end of the water supply pipe 216 is open, has a flow path opening / closing valve 217, and supplies a pressurized gas from a pressurized gas supply source 218 that generates a pressurized gas such as pressurized air. The other end is open. On the other hand, the lower end of the fluid supply path 210 is provided with a number of communication holes 204 formed in the bottom of the substrate holding head 204.
a and a large number of through holes 208 a formed in the pressing film 208 and communicate with the back surface of the wafer 203.

In this case, the cross-sectional area of the communication hole 204 a of the substrate holding head 204 is
8a, the pressurized gas supplied from the pressurized gas supply pipe 219 is supplied to the substrate holding head 204.
The pressing film 208 can press the polishing surface (surface) of the wafer 203 uniformly against the polishing pad 202 by the pressing force of the pressurized gas. So the wafer 20
The in-plane uniformity of the polishing rate for No. 3 is improved.

When the second polishing agent is supplied from the second polishing agent supply pipe 213 to the back surface of the wafer 203 or the cleaning water is supplied from the cleaning water supply pipe 216 to the back surface of the wafer 203, Pressing film 208 and wafer 203
The back surface of the wafer 203 is polished by the second abrasive or cleaning water with the relative rotation with respect to the back surface of the wafer 203, so that the foreign substances adhering to the back surface of the wafer 203 are removed.

(First Chemical Mechanical Polishing Method Performed Using Chemical Mechanical Polishing Apparatus According to Second Embodiment) Hereinafter, a first chemical mechanical polishing method performed using the chemical mechanical polishing apparatus according to the second embodiment will be described. The chemical mechanical polishing method will be described.

First, the first polishing agent 205 containing abrasive grains is supplied from the first polishing agent supply pipe 216 onto the polishing pad 201 while rotating the polishing platen 201 to rotate the polishing pad 201. . After holding the wafer 203 on the substrate holding head 204 such that the surface to be polished (front surface) of the wafer 203 faces the polishing pad 202, the substrate 203 is lowered while rotating the substrate holding head 204, and from the pressurized gas supply pipe 219. By supplying a pressurized gas to the back surface of the pressing film 208 and pressing the surface of the wafer 203 against the polishing pad 202 by the pressing film 208, chemical mechanical polishing is performed on the surface of the wafer 203.

When the polishing step on the surface of the wafer 203 is completed, the supply of the first abrasive 205 from the first abrasive supply pipe 216 is stopped, while the cleaning water is supplied from the cleaning water supply pipe 216 to the pressing film 208. And the back side of the wafer 203, and the rotation of the substrate holding head 204 and the polishing pad 201 is continuously performed. In this case, since the pressing film 208 provided on the substrate holding head 204 and the wafer 203 rotate relative to each other, the back surface of the wafer 203 is polished by the second cleaning water.
Foreign matter adhering to the back surface of the wafer 203 is reliably removed. In the cleaning process using the cleaning water, the wafer 203 is controlled by controlling the pressing force of the substrate holding head 204 against the polishing pad 201, the rotation speed of the polishing platen 201, the cleaning time, the amount of the cleaning water, the temperature of the cleaning water, and the like. Foreign matter adhering to the back surface is mechanically removed.

(Second Chemical Mechanical Polishing Method Performed Using Chemical Mechanical Polishing Apparatus According to Second Embodiment) First, the polishing pad 201 is rotated while the polishing platen 201 is rotated. A first abrasive 205 containing abrasive grains is supplied from a first abrasive supply pipe 216 onto the top 201.
Further, the wafer 203 is transferred to the substrate holding head 204 by the wafer 2.
03 is held such that the surface to be polished (front surface) faces the polishing pad 202, the substrate holding head 204 is lowered while rotating, and pressurized gas is supplied from the pressurized gas supply pipe 219 to the back surface of the pressing film 208. The surface of the wafer 203 is subjected to chemical mechanical polishing by pressing the surface of the wafer 203 against the polishing pad 202 with the supplied and pressurized gas.

As a feature of the second chemical mechanical polishing method,
When performing chemical mechanical polishing on the front surface of the wafer 203, cleaning water is supplied from the cleaning water supply pipe 216 to the back surface of the wafer 203. The reason why it is difficult to remove the foreign matter adhering to the back surface of the wafer 203 in the polishing process is because the abrasive adhered to the back surface of the wafer 203 dries, so that in the polishing process, as in the second chemical mechanical polishing method. Wafer 2
By supplying the cleaning water to the back surface of the wafer 203, it is possible to avoid a situation in which the foreign matter adhering to the back surface of the wafer 203 dries and sticks to the back surface of the wafer 203.

When the polishing step on the surface of the wafer 203 is completed, the supply of the first abrasive 205 from the first abrasive supply pipe 216 is stopped, while the cleaning water is supplied from the cleaning water supply pipe 216 to the pressing film 208. And the back side of the wafer 203, and the rotation of the substrate holding head 204 and the polishing pad 201 is continuously performed. In this case, since the pressing film 208 provided on the substrate holding head 204 and the wafer 203 rotate relative to each other, the back surface of the wafer 203 is polished by the cleaning water, so that the foreign matter adhering to the back surface of the wafer 203 is surely removed. Is removed. In particular, according to the second chemical mechanical polishing method, the cleaning water is supplied to the back surface of the wafer 203 in the polishing step, so that the back surface of the wafer 203 does not dry. Removed.

When chemical mechanical polishing is performed on the surface of the wafer 203, the cleaning water supply pipe 216 supplies the wafer 2.
Instead of supplying the cleaning water to the back surface of the wafer 03, a second abrasive containing no abrasive grains may be supplied to the back surface of the wafer 203 from the second abrasive supply pipe 213. Even in this case, it is possible to prevent the back surface of the wafer 203 from drying.

(Third Chemical Mechanical Polishing Method Performed Using Chemical Mechanical Polishing Apparatus According to Second Embodiment) First, the polishing pad 201 is rotated while the polishing platen 201 is rotated to rotate the polishing pad. A first abrasive 205 containing abrasive grains is supplied from a first abrasive supply pipe 216 onto the top 201.
Further, the wafer 203 is transferred to the substrate holding head 204 by the wafer 2.
03 is held such that the surface to be polished (front surface) faces the polishing pad 202, the substrate holding head 204 is lowered while rotating, and pressurized gas is supplied from the pressurized gas supply pipe 219 to the back surface of the pressing film 208. The surface of the wafer 203 is subjected to chemical mechanical polishing by pressing the surface of the wafer 203 against the polishing pad 202 with the supplied and pressurized gas.

As a feature of the third chemical mechanical polishing method,
When performing chemical mechanical polishing on the front surface of the wafer 203, cleaning water is supplied from the cleaning water supply pipe 216 to the back surface of the wafer 203. Thus, in the polishing process, the wafer 2
By supplying the cleaning water to the back surface of the wafer 203, it is possible to avoid a situation in which the foreign matter adhering to the back surface of the wafer 203 dries and sticks to the back surface of the wafer 203.

When the polishing process on the surface of the wafer 203 is completed, the supply of the first abrasive 205 from the first abrasive supply pipe 216 is stopped, while the second abrasive supply pipe 2 is stopped.
A second abrasive containing no abrasive grains is supplied between the pressing film 208 and the back surface of the wafer 203 from 13,
The rotation of the substrate holding head 204 and the polishing pad 201 is continuously performed. By doing so, the substrate holding head 20
Since the pressing film 208 provided in 4 and the wafer 203 rotate relative to each other, the back surface of the wafer 203 is polished by the second abrasive, so that the foreign matter adhering to the back surface of the wafer 203 is reliably removed.

In particular, according to the third chemical mechanical polishing method, since the second polishing agent is supplied to the back surface of the wafer 203 in the polishing step, the back surface of the wafer 203 does not dry. Foreign matter that has been removed is easily removed.

Further, since the second abrasive is supplied to the back surface of the wafer 203, the concentration of the first abrasive 205 supplied from the first abrasive supply pipe 216 onto the polishing pad 201 is not reduced. Therefore, the polishing rate does not decrease.

Since the second abrasive does not contain abrasive grains, even if the pressing film 208 provided on the substrate holding head 204 and the back surface of the wafer 203 rotate relative to each other,
Abrasive grains do not adhere to the back surface of wafer 203.

When chemical mechanical polishing is performed on the surface of the wafer 203, the cleaning water
Instead of supplying the cleaning water to the back surface of the wafer 03, a second abrasive containing no abrasive grains may be supplied to the back surface of the wafer 203 from the second abrasive supply pipe 213. Even in this case, it is possible to prevent the back surface of the wafer 203 from drying.

(Third Embodiment) Hereinafter, a chemical mechanical polishing apparatus and a chemical mechanical polishing method according to a third embodiment of the present invention will be described with reference to FIG.

The chemical mechanical polishing apparatus according to the third embodiment differs from the chemical mechanical polishing apparatus according to the second embodiment only in the structure of the substrate holding head. Only the structure of the substrate holding head will be described.

The chemical mechanical polishing apparatus according to the third embodiment includes a polishing platen 301 rotatably provided, a polishing pad 302 fixed on the polishing platen 301, and a polishing target substrate. The polishing pad 302 holds the wafer 303 as a polishing target and the polished surface (front surface) of the held wafer 303.
A substrate holding head 304 pressed against the polishing pad 30
A first abrasive supply pipe for supplying a first abrasive containing abrasive grains on the second substrate, and a ring-shaped guide member 307 provided on a peripheral portion of a lower surface of the substrate holding head 304. A space 309 is formed by the wafer 303 mounted on the guide member 307, the substrate holding head 304, and the polishing pad 302. In the third embodiment, a first abrasive supply pipe for supplying a first abrasive containing abrasive grains on the polishing pad 302 is not shown.

A fluid supply path 310 is provided inside the substrate holding head 304. At the upper end of the fluid supply path 310, there is provided a second flow path opening / closing valve 311 having no abrasive grains.
From the second abrasive supply source 312 for storing the second abrasive
The other end of the second abrasive supply pipe 313 that supplies the abrasive is opened, and the cleaning water is supplied from a cleaning water supply source 315 that has a flow path opening / closing valve 314 and stores the cleaning water such as pure water. The other end of the pressurized gas supply pipe 319 that opens the other end of the water supply pipe 316 and has a flow path opening / closing valve 317 and supplies pressurized gas from a pressurized gas supply source 318 that generates pressurized gas such as pressurized air. The other end is open. On the other hand, the lower end of the fluid supply path 310 is provided with a number of communication holes 304 formed in the bottom of the substrate holding head 304.
It communicates with the space 309 via a.

In the third embodiment, the surface of the wafer 303 is uniformly pressed against the polishing pad 302 by the pressurized gas supplied from the pressurized gas supply pipe 319 to the space 309. The in-plane uniformity of the polishing rate is improved.

The second abrasive supplied from the second abrasive supply pipe 313 or the cleaning water supplied from the cleaning water supply pipe 316 is introduced to the back surface of the wafer 303 to prevent the back surface from drying.

(First Chemical Mechanical Polishing Method Performed Using Chemical Mechanical Polishing Apparatus According to Third Embodiment) First, the polishing pad 301 is rotated while rotating the polishing platen 301 to rotate the polishing pad. A first abrasive containing abrasive grains is supplied from above onto the 301 from a first abrasive supply pipe (not shown).
Further, the wafer 303 is transferred to the substrate holding head 304 by the wafer 3.
After the substrate to be polished 03 is held so as to face the polishing pad 302, the substrate holding head 304 is lowered while rotating, and the pressurized gas is supplied from the pressurized gas supply pipe 319 to the space 309 to supply the pressurized gas. By pressing the polished surface of the wafer 303 against the polishing pad 302, chemical mechanical polishing is performed on the polished surface of the wafer 303.

As a feature of the first chemical mechanical polishing method,
When performing chemical mechanical polishing on the surface to be polished of the wafer 303, cleaning water is supplied from the cleaning water supply pipe 316 to the back surface of the wafer 303. As described above, when the cleaning water is supplied to the back surface of the wafer 303 in the polishing step, it is possible to avoid a situation in which the foreign matter adhering to the back surface of the wafer 303 dries and sticks to the back surface of the wafer 303.

When the chemical mechanical polishing of the surface to be polished of the wafer 303 is completed, similar to the chemical mechanical polishing method performed by using the chemical mechanical polishing apparatus according to the first embodiment,
The foreign matter attached to the back surface of the wafer 303 is removed by inverting the front and back of the wafer 303.

(Second Chemical Mechanical Polishing Method Performed Using Chemical Mechanical Polishing Apparatus According to Third Embodiment) First, the polishing pad 301 is rotated while rotating the polishing platen 301 so that the polishing pad is rotated. A first abrasive containing abrasive grains is supplied from above onto the 301 from a first abrasive supply pipe (not shown).
Further, the wafer 303 is transferred to the substrate holding head 304 by the wafer 3.
After the substrate to be polished 03 is held so as to face the polishing pad 302, the substrate holding head 304 is lowered while rotating, and the pressurized gas is supplied from the pressurized gas supply pipe 319 to the space 309 to supply the pressurized gas. By pressing the polished surface of the wafer 303 against the polishing pad 302, chemical mechanical polishing is performed on the polished surface of the wafer 303.

As a feature of the second chemical mechanical polishing method,
When performing chemical mechanical polishing on the surface to be polished of the wafer 303, a second abrasive containing no abrasive grains is supplied from the second abrasive supply pipe 313 to the back surface of the wafer 303. As described above, when the second polishing agent is supplied to the back surface of the wafer 303 in the polishing step, it is possible to avoid a situation in which the foreign matter adhering to the back surface of the wafer 303 dries and sticks to the back surface of the wafer 303.

When the chemical mechanical polishing of the surface to be polished of the wafer 303 is completed, similarly to the chemical mechanical polishing method performed by using the chemical mechanical polishing apparatus according to the first embodiment,
The foreign matter attached to the back surface of the wafer 303 is removed by inverting the front and back of the wafer 303.

[0086]

According to the first chemical mechanical polishing apparatus, after the polishing step is completed, cleaning water is supplied onto the polishing pad, and the back surface of the substrate to be polished is pressed against the polishing pad to thereby remove the polishing substrate. Since the back surface can be cleaned, foreign substances adhered to the back surface of the substrate to be polished in the polishing step can be removed with cleaning water.

According to the second chemical mechanical polishing apparatus, after the polishing step is completed, the substrate to be polished is placed on a cleaning pad with its front and back inverted, and cleaning water is supplied onto the cleaning pad. At the same time, the back surface of the substrate to be polished can be pressed against the cleaning pad to clean the back surface of the substrate to be polished, so that the foreign substances adhering to the back surface of the substrate to be polished in the polishing step can be removed with cleaning water.

According to the third chemical mechanical polishing apparatus, the second abrasive is supplied to the back surface of the substrate whose surface is polished in the polishing step, and adheres to the back surface of the substrate to be polished in the polishing step. Since it is possible to prevent the foreign matter from drying and sticking to the back surface, in a cleaning process performed later,
Foreign matter attached to the back surface of the substrate to be polished can be easily and reliably removed. In this case, since the second abrasive does not contain abrasive grains, it is possible to avoid a situation where new foreign matter adheres to the back surface of the substrate to be polished, and the second abrasive can supply the foreign matter onto the polishing pad. The situation where the concentration of the first abrasive is reduced can be avoided.

When the third chemical mechanical polishing apparatus further comprises a cleaning water supply means for supplying cleaning water to the back surface of the substrate to be polished, the cleaning water is supplied to the back surface of the substrate to be polished after the polishing step is completed. Can be supplied to wash away the second abrasive attached to the back surface of the substrate to be polished.

In the third chemical mechanical polishing apparatus, if the substrate holding head has substrate pressing means for supplying a pressurized gas to the back surface side of the substrate to be polished and pressing the substrate to be polished against the polishing pad, In the polishing step, it is possible to prevent a situation in which foreign matter attached to the back surface of the substrate to be polished is dried by the pressurized gas and sticks to the back surface of the substrate to be polished.

According to the first chemical mechanical polishing method, the back side of the substrate to be polished is turned upside down, and the back surface of the substrate to be polished is cleaned while supplying cleaning water onto the polishing pad. In the polishing step, foreign substances adhering to the back surface of the substrate to be polished can be reliably removed.

According to the second chemical mechanical polishing method, the back side of the substrate to be polished is turned upside down, and the back surface of the substrate to be polished is cleaned while supplying cleaning water onto the cleaning pad. In the polishing step, foreign substances adhering to the back surface of the substrate to be polished can be reliably removed.

According to the third chemical mechanical polishing method, the cleaning water is supplied between the back surface of the polished substrate after the polishing step and the pressing film, and the two are brought into sliding contact with each other. Since the back surface is cleaned, foreign substances adhered to the back surface of the substrate to be polished in the polishing step can be reliably removed.

According to the fourth chemical mechanical polishing method, it is possible to prevent foreign matters adhering to the back surface of the substrate to be polished in the polishing process from drying and sticking to the back surface by the cleaning water. In addition, foreign matter adhering to the back surface of the substrate to be polished can be easily and reliably removed.

According to the fifth chemical mechanical polishing method, it is possible to prevent the foreign matter adhering to the back surface of the substrate to be polished in the polishing process from drying and sticking to the back surface by the abrasive, so that in the cleaning process performed later, In addition, foreign matter adhering to the back surface of the substrate to be polished can be easily and reliably removed. In this case, since the abrasive supplied to the back surface of the substrate to be polished does not contain abrasive grains, it is possible to avoid a situation in which new foreign matter adheres to the back surface of the substrate to be polished and to supply the abrasive to the back surface of the substrate to be polished. The situation in which the concentration of the abrasive supplied on the polishing pad is reduced by the applied abrasive can also be avoided.

In the fourth or fifth chemical mechanical polishing method, if the polishing step includes a step of supplying a pressurized gas to the back surface of the substrate to be polished and pressing the substrate to be polished against the polishing pad,
In the polishing step, it is possible to prevent a situation in which foreign matter attached to the back surface of the substrate to be polished is dried by the pressurized gas and sticks to the back surface of the substrate to be polished.

Therefore, according to the first to third chemical mechanical polishing apparatuses or the first to fifth chemical mechanical polishing methods, the inside of the manufacturing apparatus in which the post-process is performed is contaminated with foreign matter, Defocusing occurs in the photolithography process due to secondary particles formed on the back surface of the substrate, and subsequent chemical mechanical polishing due to secondary particles formed on the back surface of the substrate to be polished. A situation in which uniform polishing is not performed in the process can be prevented.

[Brief description of the drawings]

FIG. 1 is a plan view showing an overall configuration of a chemical mechanical polishing apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a reversing unit in the chemical mechanical polishing apparatus according to the first embodiment of the present invention.

FIG. 3 is a schematic view showing a polishing unit and a cleaning unit in the chemical mechanical polishing apparatus according to the first embodiment of the present invention.

FIGS. 4A to 4C are schematic views showing a reversing step in the chemical mechanical polishing method performed by using the chemical mechanical polishing apparatus according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing an overall configuration of a chemical mechanical polishing apparatus according to a second embodiment of the present invention.

FIG. 6 is a sectional view of a substrate holding head in a chemical mechanical polishing apparatus according to a second embodiment of the present invention.

FIG. 7 is a sectional view of a substrate holding head in a chemical mechanical polishing apparatus according to a third embodiment of the present invention.

FIG. 8 is a perspective view showing the overall configuration of a conventional chemical mechanical polishing apparatus.

FIG. 9 is a sectional view of a substrate holding head in a conventional chemical mechanical polishing apparatus.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 chemical mechanical polishing apparatus 101 load station 102 unload station 103 wafer standby board 104A, 104B, 105C, 105D wafer mounting table 105 first wafer reversing robot 105a arm 106 second wafer reversing robot 106a arm 107 first cleaning Surface plate 108 Second cleaning surface plate 109 Polishing surface plate 110 Cleaning pad 112 Polishing pad 113 Transfer table 114 Substrate holding head 115 Cleaning water supply pipe 116 Liquid supply pipe 117 Flow path switching valve 118 Abrasive supply source 119 Cleaning liquid Supply source 120 Wafer 200 Chemical mechanical polishing apparatus 201 Polishing table 202 Polishing pad 203 Wafer 204 Substrate holding head 204a Communication hole 205 First abrasive 206 First abrasive supply pipe 207 Guide member 208 Pressing Film 208a Through hole 210 Fluid supply path 211 Flow path opening / closing valve 212 Second abrasive supply source 213 Second abrasive supply pipe 214 Flow path opening / closing valve 215 Cleaning water supply source 216 Cleaning water supply pipe 217 Flow path opening / closing valve 218 Pressurized gas supply source 301 Polishing platen 302 Polishing pad 303 Wafer 304 Substrate holding head 304a Communication hole 307 Guide member 309 Space 310 Fluid supply path 311 Flow path opening / closing valve 312 Second abrasive supply source 313 Second polishing Agent supply pipe 314 Flow path on-off valve 315 Cleaning water supply source 316 Cleaning water supply pipe 317 Flow path on-off valve 318 Pressurized gas supply source

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/304 B24B 37/04

Claims (11)

(57) [Claims] 1. A polishing surface plate rotatably provided; a polishing pad fixed on the polishing surface plate; and a polishing agent for polishing a surface of a substrate to be polished on the polishing pad. Polishing agent supply means for supplying the polishing pad; cleaning water supply means for supplying cleaning water for cleaning the back surface of the substrate to be polished onto the polishing pad; A substrate holding head for pressing a substrate against the polishing pad; and a substrate holding head such that a surface thereof faces the polishing pad.
Turn the substrate to be polished held on the pad upside down,
The substrate holding head has a surface facing the polishing pad.
Reversing means for holding the substrate on the substrate so that the back surface faces the polishing pad.
The back surface of the substrate to be polished held by the pad is
Cleaning with cleaning water supplied over the
A chemical mechanical polishing apparatus for removing foreign matter adhering to the back surface of a substrate to be polished . 2. A polishing surface plate rotatably provided; a polishing pad fixed on the polishing surface plate; a cleaning surface plate rotatably provided; A cleaning pad provided thereon, an abrasive supply means for supplying an abrasive for polishing the surface of the substrate to be polished onto the polishing pad, and a cleaning water for cleaning the back surface of the substrate to be polished , Cleaning water supply means for supplying the cleaning pad with the polishing pad; and a polishing water supply means movably provided between the upper side of the polishing pad and the upper side of the cleaning pad. A substrate holding head that individually presses a substrate against the polishing pad and the cleaning pad; and a substrate holding head so that a surface faces the polishing pad.
Turn the substrate to be polished held on the pad upside down,
The substrate holding head so that the surface faces the cleaning pad.
Reversing means for holding the substrate on the substrate so that the back surface faces the cleaning pad.
The back surface of the substrate to be polished held by the pad is
Cleaning with cleaning water supplied over the
A chemical mechanical polishing apparatus for removing foreign matter adhering to the back surface of a substrate to be polished . 3. A polishing surface plate rotatably provided, a polishing pad fixed on the polishing surface plate, and a substrate to be polished which detachably holds and holds the substrate to be polished. A substrate holding head pressed against a pad; first abrasive supply means for supplying a first abrasive containing abrasive grains on the polishing pad; and a substrate to be polished held by the substrate holding head. Back of
Contains no abrasive grains and prevents drying of the back surface of the substrate to be polished.
A second polishing agent supply means for supplying a second polishing agent to be stopped . 4. The chemical mechanical polishing apparatus according to claim 3, further comprising cleaning water supply means for supplying cleaning water to the back surface of the substrate to be polished held by said substrate holding head. . 5. The substrate holding head has substrate pressing means for pressing a substrate to be polished against a polishing pad by supplying a pressurized gas to the back side of the substrate to be polished held by the substrate holding head. The chemical mechanical polishing apparatus according to claim 3, wherein 6. A polishing step of polishing a surface of a substrate to be polished while supplying an abrasive onto the polishing pad; a reversing step of reversing the front and back of the substrate to be polished after the polishing step; A cleaning step of cleaning the back surface of the substrate to be polished while supplying cleaning water to the substrate. 7. A polishing step of supplying an abrasive onto the rotating polishing pad and pressing the surface of the substrate to be polished against the rotating polishing pad, thereby polishing the surface of the substrate to be polished, and the polishing step is completed. A transfer step of transferring the substrate to be polished onto the cleaning pad with its front and back inverted, and supplying cleaning water onto the cleaning pad and pressing the back surface of the substrate to be polished against the cleaning pad, thereby forming the substrate to be polished. A cleaning step of cleaning the back surface. 8. A polishing step of supplying an abrasive onto the polishing pad and pressing the substrate to be polished from its back surface onto a rotating polishing pad via a pressing film, thereby polishing the surface of the substrate to be polished; A cleaning step of cleaning the back surface of the substrate to be polished by supplying cleaning water between the substrate to be polished and the film for pressing and bringing the back surface of the substrate to be polished into sliding contact with the film for pressing. A chemical mechanical polishing method characterized in that: 9. A chemical mechanical polishing method comprising a polishing step of polishing a surface of a substrate to be polished by supplying a polishing agent onto the polishing pad and pressing the surface of the substrate to be polished against a rotating polishing pad. The polishing step is characterized in that the polishing step includes a step of supplying a cleaning liquid to the back surface of the substrate to be polished whose surface is polished. 10. A chemical mechanical polishing method comprising a polishing step of polishing a surface of a substrate to be polished by supplying a polishing agent onto the polishing pad and pressing the surface of the substrate to be polished against a rotating polishing pad. The polishing step is characterized in that the polishing step includes a step of supplying an abrasive containing no abrasive grains to the back surface of the substrate to be polished, the surface of which is polished. 11. The chemical process according to claim 9, wherein the polishing step includes a step of pressing the substrate to be polished against the polishing pad by supplying a pressurized gas to the back side of the substrate to be polished. Mechanical polishing method.