JPH10128655A - Polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To approximate to a desired polishing amount with high accuracy by polishing at one polishing part, and then polishing at the other polishing part for the shortage to a desired polishing amount. SOLUTION: At a first polishing part 40, approximation to a preset film thickness is performed, and a surface to be polished of an upper edge is flattened to be global. At a measuring part 90, insufficient polishing amount to a preset film thickness is made clear from the residual film thickness. Next, the upper edge is transferred from the measuring part 90 to the second polishing part 50 by a transport mechanism 60. In the second polishing part, secondary polishing is performed. Secondary polishing is to again polish to a preset film thicknesses which is not attained by the primary polishing and to remove projecting parts caused by a fine pattern which has not been removed by primary polishing to be flattened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus for polishing an object to be polished such as a semiconductor wafer, and more particularly to a polishing apparatus capable of improving flatness.

[0002]

2. Description of the Related Art With the recent high integration and high speed of LSI, multilayer wiring technology is becoming more and more important. LS
Advantages of using a multilayer wiring in I include an increase in the degree of freedom in wiring layout due to multilayering, a reduction in wiring resistance by shortening the wiring length, and the like. However, such super L
In the SI, various problems arise because the processing dimensions of elements and wirings are becoming submicron.

For example, in a submicron wiring, the aspect ratio (pattern height / pattern width) of the wiring and the groove between the wirings becomes large, and the conventional CVD (chemical vapor deposition) is performed.
In a method of forming an insulating film or the like using a sputtering method or a sputtering method, sufficient step coverage cannot always be obtained. When the aspect ratio becomes large and the surface step becomes steep, if the step exceeds the depth of focus limit of exposure, exposure failure will be caused, so that disconnection of the upper layer wiring, short circuit between lines, or deterioration of processing accuracy of the wiring pattern will occur. . Therefore, in order to realize a highly reliable multilayer wiring, it is necessary to overcome many technical problems that occur in both the film forming technology and the fine processing technology. In particular, for an interlayer insulating film used for a multilayer wiring, it is required that the surface of the base insulating film is sufficiently flat with respect to the upper wiring.

In order to solve the problem of wiring delay due to the high integration of LSI, the wiring material is changed to C instead of current Al.
It has been proposed to use u. Since it is difficult to etch Cu, a process of embedding a wiring material in a groove is required. Therefore, as in the case of the interlayer insulating film, it is required to bury the wiring film in a wiring groove having a large aspect ratio and to planarize the wiring groove.

The insulating film and the wiring are formed by the CVD method or the sputtering method. In response to the above-mentioned demand for improving the flatness and filling in the groove (removing the film formed other than the groove), the CMP method is required.
(Chemical Mechanical Polishing) is applied.

FIG. 8 is a diagram showing a main part of a CMP polishing apparatus 10 for performing polishing by the CMP method. CMP
The polishing apparatus 10 comprises: a carrier 11 for holding a wafer W on which a semiconductor or a magnetic recording element is formed;
1, a drive motor 12 for rotating and driving the carrier 1, an air cylinder 13 for pressing the carrier 11 and the drive motor 12 against a table 14 to be described later with a predetermined pressure, a table 14 opposed to the carrier 11, A polishing cloth (cloth) 15 made of nonwoven fabric or foamed polyurethane is provided, and a drive motor 16 for rotating the table 14 is provided. In addition, 17 in FIG.
2 shows a polishing liquid supply section for supplying the polishing liquid.

As shown in FIG. 9, the carrier 11 is provided to face the upper surface of the table 14, and holds and holds the wafer W on the surface facing the table 14. In the CMP polishing apparatus 10, while the wafer W is held by the carrier 11, the polishing liquid L is supplied from the polishing liquid supply unit 17 onto the polishing pad 15 while the carrier 11 and the table 14 are rotated by the drive motors 12 and 16, respectively. The supplied and polished liquid L or the chemical action of the polishing liquid L and the physical action of the abrasive grains in the polishing liquid L flatly polish the surface irregularities of the wiring film or the insulating film due to the influence of element formation on the wafer W.

[0008]

SUMMARY OF THE INVENTION As described above, the conventional C
The MP polishing apparatus 10 has the following problems.
That is, first, a method of flattening unevenness of a semiconductor device by mechanical polishing (Japanese Patent Application Laid-Open No. 1-216537) or a method of applying a uniform load to the entire wafer surface and flattening the semiconductor device (Japanese Patent Application Laid-Open No. 7-148262). And so on. However, as the degree of integration of the device increases, the wavelength of lithography becomes shorter, and there is no margin in the depth of focus. Therefore, there is a possibility that the yield in the lithography process may decrease due to unevenness due to the underlying wiring pattern.

The uniformity of the film thickness on the surface of the wafer W is within ± 5.
Although the height of fine irregularities due to wiring steps has been improved to about ± 10% and the height of fine irregularities due to wiring steps has been improved to about 0.1 μm, so-called global flatness, which is the flatness of the entire wafer surface, and flatness for fine patterns in a chip. For, further improvement in accuracy is required. It is also required that the thickness of the insulating film be controlled on the order of nm.

Furthermore, since the CMP method lacks process stability, if the polishing time is determined empirically, there is a possibility that the film thickness after polishing of each wafer may vary.

Second, in the CMP polishing apparatus 10, FIG.
(A) and (b). 10A is a cross-sectional view schematically showing the wafer W after the formation of the insulating film Q, and FIG. 10B is a cross-sectional view schematically showing the wafer W after polishing. .

As shown in FIG. 10A, before polishing, the insulating film Q is formed with a substantially predetermined thickness as a whole, and the protrusions Qa and Qa are formed on the insulating film Q above the wiring pattern P. Q
b occurs. The wiring pattern P includes an isolated wiring pattern Pa and a concentrated wiring pattern Pb. Conventional C
In the MP polishing apparatus 10, the protrusion Qa on the isolated wiring pattern Pa has a characteristic of being relatively quickly polished. Therefore, there is a problem that the protruding portions Qb on the dense wiring pattern P cannot be removed. This is because, for example, hardness 95 (measurement method JIS)
K-6301), the elasticity of the polishing cloth 15 causes a load concentration on the protruding portion Qa on the isolated wiring pattern Pa, resulting in an increase in the polishing removal rate. .

Further, due to the elastic deformation of the polishing pad 15, the load tends to be concentrated on the outer peripheral portion of the wafer W, and there is a property that a load distribution occurs on the surface Wa to be polished of the wafer W. The load distribution is as a whole shown by the α curve in FIG.
It should be noted that a larger load generally results in a higher polishing removal rate.

Further, frictional heat is generated on the surface Wa to be polished of the wafer W by friction with the polishing pad 15. At this time, since the wafer W is held by the carrier 11, the heat does not escape, the temperature increases at the center of the wafer W, and a temperature distribution occurs on the polished surface Wa (β curve in FIG. 11). In general, the higher the temperature, the higher the polishing removal rate.

With these two types of load distribution and temperature distribution, the polishing removal rate becomes non-uniform (γ curve in FIG. 11).
There was a problem that global flatness could not be maintained. In recent years, the diameter of the wafer W has been increased from 200 mm to 300 mm, and it is difficult to achieve global flatness and flatness for a fine pattern simultaneously.

Accordingly, the present invention provides a polishing method capable of simultaneously realizing global flatness, ie, uniformization of the overall film thickness on the surface to be polished of a workpiece, such as a wafer, and fine flatness, ie, removal of fine irregularities. It is intended to provide a device.

[0017]

In order to solve the above-mentioned problems and to achieve the object, the invention according to the first aspect is characterized in that a polishing object is slid on a first polishing cloth to perform polishing. A polishing section, a measuring section for measuring a polishing amount of the object to be polished polished by the first polishing section, and a first polishing cloth for the object to be polished based on the polishing amount measured by the measuring section. And a second polishing section for performing polishing by sliding the second polishing cloth different from the second polishing cloth.

According to the invention described in claim 2, in the invention described in claim 1, it is preferable that the second polishing cloth has a higher hardness than the first polishing cloth. According to a third aspect of the present invention, in the second aspect, the object to be polished is formed of a silicon oxide material, the first polishing cloth is a foamed polyurethane, and the second polishing cloth is a chloride cloth. It is preferred that the resin be made of at least one of vinyl resin, polyethylene, polystyrene, polypropylene, and acrylonitrile butadiene styrene.

According to a fourth aspect of the present invention, in the first aspect, the first polishing section, the measuring section, and the second polishing section are arranged on the same table. preferable.

According to a fifth aspect of the present invention, there is provided a carrier for exposing and supporting a surface to be polished of a plate-like object to be polished, a polishing cloth disposed opposite to the surface to be polished, A driving unit that relatively moves the carrier and the polishing cloth along the surface to be polished so as to polish the surface to be polished by sliding the polishing cloth; and A pressure sensor that measures the pressure distribution that the polished surface receives from the polishing cloth, a temperature sensor that measures the temperature distribution of the polished surface, and non-contact measurement data measured by the pressure sensor and the temperature sensor. The transmission unit includes: a transmission unit that transmits the measurement data; and a control unit that receives the measurement data transmitted from the transmission unit via a reception unit.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the control section controls the pressure distribution of the polished surface based on the measurement data received via the receiving section. And a calculation unit for calculating the temperature distribution.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the control section controls the surface to be polished based on the pressure distribution and the temperature distribution calculated by the calculation section. It is preferable to include a polishing removal rate calculation unit that calculates a polishing removal rate distribution.

According to an eighth aspect of the present invention, in the invention according to the seventh aspect, the control section calculates a correction value based on the polishing removal rate distribution calculated by the polishing removal rate calculating section. The carrier includes a biasing unit that distributes and biases the surface to be polished toward the polishing cloth based on the correction value calculated by the correction value computing unit. Is preferred.

As a result of taking the above measures, the following operation occurs. That is, in the first aspect of the present invention, the first polishing is performed by sliding the object to be polished on the first polishing cloth.
A polishing section, a measuring section for measuring a polishing amount of the object to be polished polished by the first polishing section, and a second polishing section different from the first polishing cloth based on the polishing amount measured by the measuring section. Since there is provided a second polishing section that performs polishing by sliding on a polishing cloth, after polishing in the first polishing section, a portion less than a desired polishing amount can be polished in the second polishing section. .
For this reason, it is possible to approach the desired polishing amount with high accuracy.

According to the second aspect of the invention, the hardness of the second polishing cloth is higher than that of the first polishing cloth. For this reason,
Performing global flattening in the first polishing section and making the polishing removal rate constant regardless of the unevenness of the surface to be polished in the second polishing section, thereby removing fine unevenness to perform fine flattening. Can be.

According to the third aspect of the present invention, the object to be polished is formed of a silicon oxide material, the first polishing cloth is foamed polyurethane, and the second polishing cloth is vinyl chloride resin, polyethylene, polystyrene, polypropylene, acrylic. At least one of nitrile butadiene styrene was used.

According to the fourth aspect of the present invention, since the first polishing section, the measuring section, and the second polishing section are arranged on the same table, the installation space can be reduced and the transfer time can be reduced. And throughput can be improved.

According to the fifth aspect of the present invention, a carrier that exposes and supports a surface to be polished of a plate-like object to be polished, a polishing cloth disposed opposite to the surface to be polished, a polishing cloth and a polishing cloth And a driving unit that relatively moves the carrier and the polishing cloth along the surface to be polished so that the surface to be polished is polished, and the carrier is provided, and the surface to be polished of the object to be polished is received from the polishing cloth. A pressure sensor for measuring the pressure distribution, a temperature sensor for measuring the temperature distribution of the surface to be polished, a transmitter for transmitting the measurement data measured by the pressure sensor and the temperature sensor in a non-contact manner, and a transmitter for transmitting the measurement data. Since a control unit for receiving measurement data via the receiving unit is provided, the pressure and temperature on the surface to be polished can be monitored from outside without using a complicated mechanism such as a slip ring.

According to the sixth aspect of the present invention, the control unit includes the calculation unit that calculates the pressure distribution and the temperature distribution of the polished surface based on the measurement data received via the reception unit. The pressure distribution and the temperature distribution on the surface to be polished can be monitored from the outside.

[0030] In the invention described in claim 7, the control unit includes a polishing removal speed calculation unit that calculates a polishing removal speed distribution on the surface to be polished based on the pressure distribution and the temperature distribution calculated by the calculation unit. Therefore, it is possible to externally monitor the polishing removal rate distribution of the surface to be polished.

In the invention described in claim 8, the control unit includes a correction value calculation unit that calculates a correction value based on the polishing removal speed distribution calculated by the polishing removal speed calculation unit. Since the urging unit for distributing and urging the surface to be polished toward the polishing cloth based on the correction value calculated by the value calculating unit is provided, the polishing removal rate distribution on the surface to be polished can be corrected. . Therefore, for example, the polishing removal rate of the polished surface can be made uniform, and global flattening can be realized.

[0032]

FIG. 1 is a perspective view showing a CMP polishing apparatus 20 according to a first embodiment of the present invention, and FIG. 2 is a flowchart showing a polishing procedure of the CMP apparatus 20. FIG.
As shown in the figure, the CMP polishing apparatus 20 includes a mounting table 31 on which the respective mechanisms are integrally mounted, and a control unit 3 for cooperatively controlling the respective mechanisms.
2 is provided.

The mounting table 31 has a first polishing section 40 and a second polishing section 40.
Polishing unit 50 and transport mechanism 60 for transporting wafer W
And a storage unit 70 for storing the wafer W, a cleaning and drying unit 80 for cleaning and drying the wafer W, and a measuring unit 90 for measuring the film pressure of the wafer W.

The first polishing section 40 includes a table section 41, a carrier section 42, and an abrasive supply section 43. The table section 41 includes a rotary table 41a, a first polishing cloth 41b stuck on the upper surface of the rotary table 41a, and a drive motor (not shown) for rotating the rotary table 41a at a predetermined rotation speed.

The first polishing cloth 41b is made of, for example, a foamed polyurethane material having a hardness of 60. Carrier part 42
Is a carrier 42a for holding a wafer (substrate to be polished) W with the surface to be polished Wa facing the polishing cloth 41b, a shaft support 42b for supporting the carrier 42a, and a support for supporting the shaft support 42b. And an arm 42c.
The support arm 42c is connected to the carrier 42 via a shaft support 42b.
a is given a predetermined rotation speed and a downward pressing force.

The lower surface of the carrier 42a is
Are smoothed so that the load applied to the wafer W becomes uniform, and a vacuum suction hole is formed, so that the wafer W can be vacuum chucked by a suction device (not shown). Further, since the temperature of the wafer W during polishing rises to 50 ° C. or more, the carrier 42a is made of Al ₂ O ₃ or SiC having a small coefficient of thermal expansion to prevent thermal distortion.
It is made of such materials.

The second polishing section 50 includes a table section 51, a carrier section 52, and an abrasive supply section 53. The table section 51 includes a rotary table 51a, a second polishing pad 51b stuck on the upper surface of the rotary table 51a, and a drive motor (not shown) for rotating the rotary table 51a at a predetermined rotation speed.

The second polishing cloth 51b is formed of, for example, a vinyl chloride resin having a hardness of 120. The carrier section 52
The wafer (object to be polished) W is polished to a polishing surface 51 with a polishing cloth 51.
b, a carrier 52a held in an opposed state, a shaft supporting portion 52b for supporting the carrier 52a, and a shaft supporting portion 5b.
And a support arm 52c for supporting the second arm 2b. The support arm 52c applies a predetermined rotational speed and a downward pressing force to the carrier 52a via the shaft support 52b. Note that the carrier 52a is formed similarly to the carrier 42a.

The transport mechanism 60 includes a transport guide 61, a slider 62 that reciprocates along the transport guide 61, and a hand 63 supported by the slider 62. The storage unit 70 includes a loader 71 and an unloader 72. In FIG. 1, reference numeral 71a denotes a cassette for storing the wafer W before polishing, and reference numeral 72a denotes a cassette for storing the wafer W after polishing.

The cleaning / drying unit 80 includes a brush cleaning mechanism 81
, A pure rinsing mechanism (not shown), and a spin drying mechanism 82
And The measuring section 90 includes a mounting section 91 on which the wafer W is mounted, a light source 92 for irradiating the wafer W mounted on the mounting section 91 with the laser light L, and the like. A reflection intensity detector 93 for detecting the intensity of the laser beam L reflected on the W and calculating the remaining film thickness δ, and a CCD camera 94 for recognizing and aligning the measurement pattern position of the wafer W are provided. .

The CMP polishing apparatus 20 configured as described above
Then, flattening polishing of the wafer W is performed. 3A to 3C are cross-sectional views schematically showing a polished state of the polished surface Wa of the wafer W, and the upper side is a polished surface Wa.

In FIG. 3, V is a base material, P is a wiring pattern formed of an Al material, and Q is a 1 μm-thick SiO ₂ insulating film formed by a CVD method. The wiring pattern P has
There are isolated wiring patterns Pa and densely arranged wiring patterns Pb. Further, since the insulating film Q is affected by the wiring pattern P when forming the insulating film Q, unevenness occurs, so that a convex portion Qa above the wiring pattern Pa and a convex portion Qb above the wiring pattern Pb are formed. These convex portions Qa, Q
The height of b is about 500 nm.

As shown in FIG. 3A, the film thickness of the insulating film Q is not uniform since the film thickness is not uniform immediately after the film formation by the CVD method.
The distribution is 5%. The height and width of the wiring pattern P are 500 nm and 300 nm, respectively, and the wiring interval is about 350 nm to 1 mm, which differs depending on the location.

First, one of the wafers 200 having a diameter of 200 mm formed as a device is taken out of the cassette 71 a of the loader 71 by the hand 63 of the transfer mechanism 60 and transferred to the first polishing section 40.

In the first polishing section 40, the wafer W is vacuum-chucked to the carrier 42a. Rotary table 41a
The rotating table 41a and the carrier 42a are respectively rotated at a predetermined speed while the polishing surface Wa of the wafer W is in contact with the first polishing cloth 41b, and a downward load is applied to the wafer W. At the same time, the abrasive is supplied from the abrasive supply unit 43.

The rotary table 41a and the carrier 42
When rotating a, the rotation direction of the rotary table 41a and the carrier 42a is reversed so that the relative speed at the contact portion between the wafer W and the first polishing cloth 41b is uniform.
The rotation speed of the turntable 41a and the rotation speed of the carrier 42a are the same. This rotation speed is in the range of 10 to 200 rpm.

On the other hand, the abrasive supplied from the abrasive supply unit 43 is CeO or colloidal Si having a particle size of 0.5 μm.
The O ₂ is used as the diffused into pure water. In the first polishing section 40, the thickness of the polished surface Wa of the wafer W is globally planarized by approaching the set film thickness. As a result, the unevenness of the film on the polished wafer device has a smooth unevenness as shown in FIG. That is,
As the film thickness approaches the set film thickness, the distribution of the film thickness of the insulating film Q before polishing becomes substantially uniform. In the first polishing, since the first polishing cloth 41b having a hardness of 60 is used, the first polishing cloth 41b is easily elastically deformed, and the first polishing cloth 41b is polished between the independent convex portion Qa and another convex portion Qb. Different removal rates. Therefore, only the protrusion Qa is removed quickly, and the protrusion Qb on the wiring pattern Pb is not completely removed.

Next, the wafer W after the primary polishing is transferred from the first polishing section 40 to the cleaning / drying section 80 by the transfer mechanism 60. In the cleaning / drying unit 80, the abrasive material attached to the insulating film Q in the primary polishing by the brush cleaning mechanism 81 is brush-cleaned using pure water. And after rinsing with pure water,
Spin drying is performed in the spin drying unit 82.

Next, the wafer W is transferred to the measuring section 90 by the transfer mechanism 60. The measuring unit 90 measures the film thickness in order to measure how close to the set film thickness value is due to the primary polishing. In the film thickness measurement, the position of the measurement pattern on the wafer W is recognized by the CCD camera 94, and after alignment, the laser light L is emitted from the light source 92. This reflected light is made incident on the reflection intensity detector 93.

The reflection intensity detector 93 obtains the remaining film thickness δ as follows. That is, assuming that the wavelength of the laser light L is λ and the incident angle of the laser light L with respect to the insulating film Q is θ, the remaining film thickness δ on the wiring or on the Si substrate is obtained by the following equation. That is, δ = mλ / 2sin θ (1) where m is the order. When the wavelength λ is changed while the incident angle θ is kept constant, light reflection from the surface of the insulating film Q and the substrate V causes interference, and a high reflection intensity is exhibited. By specifying the wavelength at which the radiation intensity reaches a peak, the remaining film thickness δ is obtained from the equation (1).

Therefore, in the measuring section 90, the insufficient polishing amount with respect to the preset film thickness becomes apparent from the remaining film thickness δ. This insufficient polishing amount is polished by the second polishing unit 50 as described later.

Next, the wafer W is transferred from the measuring section 90 to the second polishing section 50 by the transfer mechanism 60. In the second polishing section, secondary polishing is performed. Secondary polishing is to perform re-polishing to a set film thickness that has not been reached in the primary polishing,
The protrusions Qb resulting from the fine patterns that cannot be completely removed by the primary polishing shown in FIG. 3B are removed and flattened.

In the secondary polishing, by using a polishing material harder than that in the primary polishing, the polishing removal rate can be made constant regardless of the density of the wiring pattern. As a result, the convex portion Qb is also removed as shown in FIG.
The chip pattern of the wafer W can be finely flattened. Furthermore, the shortage of polishing measured by the measuring unit 90 can be polished, and can be set to an allowable range of a preset value.

Next, the wafer W is transferred from the second polishing section 50 to the cleaning / drying section 80 again, and the abrasive adhered on the insulating film Q is washed away in the same manner. After that, the wafer W is stored in the cassette 72a of the unloader 72 of the storage unit 70.

The wafer W flowing along this flow
Are controlled and determined by the control unit 32. The transfer / setting timing, the polishing conditions in the first polishing unit, the cleaning / drying conditions, the film thickness measurement, and the polishing conditions in the second polishing unit based on the film thickness measurement result are all controlled and determined.

With this apparatus and method, global flattening of the entire wafer surface, fine flattening of the chip pattern, and suppression of variation in the remaining film thickness after polishing for each wafer, which could not be achieved by the prior art, are achieved.

As described above, C according to the first embodiment is
According to the MP polishing apparatus 20, for example, the thickness of the insulating film Q of the wafer W having a diameter of 200 mm can be uniformly flattened to ± 1% or less, and the step caused by the fine pattern can be reduced to 10 nm or less. The variation in the remaining film thickness of each wafer W is ± 10 n.
m or less. Therefore, global flattening and fine chip pattern flattening can be performed.

In the first polishing unit 40, the amount polished is measured by the measuring unit 90 to measure the remaining film thickness δ, and the second polishing unit 50 polishes the insufficient polishing amount. It can approach the set film thickness.

Further, the first polishing section 40 and the second polishing section 5
Since the measuring unit 90 is arranged on the same mounting table 31, the installation space can be narrowed, the transfer time can be shortened, and the throughput can be improved.

In the first embodiment, the second polishing cloth 51b is made of vinyl chloride resin. However, the second polishing cloth 51b is not limited to vinyl chloride resin, and may be made of a material harder than the first polishing cloth, such as polyethylene, polystyrene, polypropylene, and acrylic. Any of nitrile butadiene styrene (ABS) resins may be used.

FIG. 4 is a circuit diagram of a second embodiment of the present invention.
It is a figure which shows the principal part of 20 A of MP polishing apparatuses. In addition, the present apparatus 20A includes a first polishing unit 100 instead of the first polishing unit 40 of the CMP polishing apparatus 20 according to the above-described first embodiment.
Is provided. Therefore, only the first polishing unit 100 will be described.

The first polishing section 100 includes a table section 110
And an abrasive supply section 120 and a carrier section 130. The table section 110 includes a rotary table 111, a first polishing cloth 112 having a hardness of 95, which is affixed to the upper surface of the rotary table 111, and a drive motor 113 for rotating the rotary table 111 at a predetermined rotation speed.

As shown in FIG. 5, the carrier section 130 holds a carrier 131 that holds the surface to be polished Wa of the wafer W facing the first polishing cloth 112,
132, a drive motor 133 for rotating and driving the shaft support 132, a pressing drive 134 for pressing the carrier 131 together with the drive motor 133 downward in FIG. 5, and a support arm for supporting the whole. (Not shown).

The carrier 131 is provided with a correction mechanism 140 for correcting the polishing removal rate distribution as described later. The correction mechanism 140 includes a rotation block 150 provided on the carrier 131 and a control block 160.

The rotating block 150 is disposed on the lower surface of the carrier 131 and has a holding plate 151 for holding the upper surface of the wafer W smoothly, and a plurality of thermocouples 152 distributed in the holding plate 151. A plurality of load cells 153 distributed in the same manner, a plurality of piezoelectric elements 154 similarly distributed and disposed, and a control unit 155 disposed on the outer periphery of the shaft support 132 are provided.

The control unit 155 includes a sensor amplifier 156 connected to each thermocouple 152 via a lead wire, a sensor amplifier 157 connected to each load cell 153 via a lead wire, and a piezoelectric amplifier 154, which will be described later. A piezoelectric element driving section 158 for supplying electric power based on the command signal, and a transmitting / receiving section 161 of a control block 160 described later connected to the sensor amplifiers 156 and 157 and the piezoelectric element driving section 158.
And a transmission / reception unit 159 that communicates with the user.

The control block 160 is provided on the outer peripheral side of the control unit 155 and has an arcuate transmission / reception unit 161 for communicating with the transmission / reception unit 159 of the rotation block 150. The control block 160 is connected to the transmission / reception unit 161. The received optical signal is serially transmitted to a personal computer 163 described later.
A converter 162 for parallelizing and transferring the data;
1 and a personal computer 163 connected to the converter 162.

The personal computer 163 has a function of calculating a temperature distribution and a pressure distribution based on the input measurement data, and a function of calculating a polishing removal rate distribution. Further, it has a function of comparing the polishing removal rate distribution with a preset set value and outputting a pressure correction value.

As shown in FIG. 6, the transmission / reception unit 159 includes a channel switch 159a for switching the input from the sensor amplifier 156 connected to each of the thermocouples 152 (CH1 to CHn) at a predetermined timing, and a channel switch 159a. An address setting device 159b for setting an address to the measurement data output from the 159a, an A / D converter 159c for A / D converting the measurement data output from the address setting device 159b, and an A / D converter 159
light emitting element 15 for transmitting a digital signal output from
9d, a light receiving element 159e that receives an optical signal from a light emitting element 161b described later, and the above-described channel switcher 1 based on the optical signal received by the light receiving element 159e.
Trigger receiving device 159f for outputting a trigger signal to 59a
And In FIG. 4, reference numeral 159g denotes a light-receiving element for receiving a correction value described later, and 159h denotes a light-emitting element which emits a trigger signal and emits light at all times.

As shown in FIG. 6, the transmitting / receiving section 161 includes a light receiving element 161a, a light emitting element 161b, and a light emitting element 161.
and a light-emitting element driving section 161c that constantly drives b. In FIG. 4, reference numeral 161d denotes a light emitting element for transmitting a correction value, and 161e denotes a light receiving element for receiving a trigger signal.

The positional relationship between the transmitting / receiving section 159 and the transmitting / receiving section 161 is such that the light emitting element 161b and the light receiving element 161a face each other when the light emitting element 159d and the light receiving element 161a face each other.
59e are provided so as to face each other, and the distance is 1
It is provided so as to be 00 mm or less. Further, a similar configuration is provided for each load cell 153.

The measurement data received by the light receiving element of the receiving device is serial-parallel converted for processing by a personal computer, and then transmitted to the personal computer via an interface, and finally processed by the personal computer.

The thus configured CMP polishing apparatus 20
In the first polishing section 100 of A, primary polishing is performed as follows. In the same manner as in the first embodiment, the wafer W
Is started, and measurement by the thermocouple 152 and the load cell 153 is started. These thermocouples 152
And the output from the load cell 153 is
6, 157 are input to the transmission / reception unit 159.

When the transmission / reception section 159 faces the transmission / reception section 161, an optical signal is input from the light emitting element 161b which constantly emits light to the light receiving element 159e. The trigger signal is input from the trigger receiving device 159f to the channel switch 159a by this optical signal.

On the other hand, in the channel switch 159a,
When the signal input for one channel is completed, the signal input for the second channel is performed. This is sequentially repeated to input a signal corresponding to n channels. Further, in synchronization with the channel switching, the input signal is supplied to the address setter 159b.
, An address is set, and A / D conversion is performed by the A / D converter 159c.

When the trigger signal is input, the light emitting element 159d emits light, and the light receiving element 161a receives the optical signal. The optical signal received by the light receiving element 161a is subjected to serial-parallel conversion by the converter 162 and then input to the personal computer 163 via the interface.

The personal computer 163 calculates the temperature distribution and pressure distribution of the wafer W based on the temperature data and pressure data of each channel. Since the temperature distribution and the load distribution are generated on the surface Wa to be polished of the wafer W with the elapse of the polishing time, the temperature distribution and the pressure distribution are shown in FIG.
It is as shown in Further, the personal computer 163 calculates a polishing removal rate distribution from the temperature distribution and the pressure distribution.

On the other hand, in the primary polishing, since the main purpose is to flatten the wafer W globally, it is required that the difference in speed be as small as possible. Therefore, the amount of displacement of each piezoelectric element (solid line c in FIG. 7) is determined based on the calculated polishing removal rate distribution. This displacement amount becomes the pressure correction value.
That is, the pressure correction value is a value for urging a portion having a low polishing removal rate downward in FIG. 4 by driving and displacing the piezoelectric element 154.

The pressure correction value is sent to the light emitting element 161d of the transmitting / receiving section 161 and the light receiving element 159g of the transmitting / receiving section 159.
Sent when is facing. This transmission timing is performed when the light emission of the light emitting element 159h is received by the light receiving element 161e.

FIG. 7D shows the polishing removal rate distribution after the correction. As a result, the polishing removal rate is made substantially uniform, and global flatness in the primary polishing can be realized. Note that the pressure correction value is set, for example, to reduce the displacement of the piezoelectric element 154 at a position where the load on the outer peripheral portion of the wafer W is concentrated or at a position where the temperature of the central portion of the wafer W is high. Table 1 shows a pressure distribution range, a temperature distribution range, and a polishing removal rate distribution in the conventional apparatus and the apparatus of the present embodiment.

[0081]

[Table 1]

According to Table 1, it can be seen that the polishing removal rate is almost uniform. After the completion of the primary polishing, the remaining film thickness δ is measured in the same manner as in the above-described first embodiment, and the second polishing section 50 repolishes and removes fine irregularities.

As described above, C according to the second embodiment
According to the MP polishing apparatus 20A, even if a temperature distribution and a pressure distribution occur in the wafer W in the primary polishing and the polishing removal rate becomes non-uniform, the polishing removal rate can be increased by driving the piezoelectric element to urge the wafer W. Can be made uniform. Therefore, global flattening can be realized.

Further, in this apparatus, the collection of temperature data and pressure data and the transmission and reception of the correction amount are performed by a non-contact method by optical communication, so that the apparatus is compared with a contact type using a slip ring or the like. Can be downsized.

The present invention is not limited to the above embodiments. That is, in the above embodiment,
Although the wafer has been exemplified as the object to be polished, the object is not limited to the wafer. Further, although the load cell is used as the pressure sensor, the pressure may be appropriately converted using a strain gauge, a displacement meter, a load, or the like. In addition, it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0086]

According to the first aspect of the present invention, after polishing in the first polishing section, an amount less than a desired polishing amount can be polished in the second polishing section. For this reason, it is possible to approach the desired polishing amount with high accuracy.

According to the second aspect of the present invention, the first
By performing global flattening in the polishing section and making the polishing removal rate constant in the second polishing section irrespective of the unevenness of the surface to be polished, fine unevenness can be removed, thereby performing fine flattening. .

According to the third aspect of the present invention, the object to be polished is formed of a silicon oxide material, the first polishing cloth is polyurethane foam, and the second polishing cloth is vinyl chloride resin, polyethylene, polystyrene, polypropylene. And at least one of acrylonitrile butadiene styrene. Therefore, a film thickness of ± 10 nm can be obtained.

According to the invention described in claim 4, the installation space can be narrowed, the transfer time can be shortened, and the throughput can be improved. According to the invention described in claim 5, the pressure and the temperature on the surface to be polished can be monitored from outside without using a mechanically complicated mechanism such as a slip ring, so that the maintenance can be performed without causing a disturbance. Is also easy.

According to the present invention, the pressure distribution and the temperature distribution on the surface to be polished can be monitored from the outside. According to the invention described in claim 7, it is possible to externally monitor the polishing removal rate distribution of the surface to be polished.

According to the eighth aspect of the present invention, the polishing removal rate distribution on the surface to be polished can be corrected. Therefore, for example, the polishing removal rate of the polished surface can be made uniform, and global flattening can be realized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a CMP polishing apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a polishing procedure in the apparatus.

FIG. 3 is a cross-sectional view schematically showing a state of polishing by the apparatus.

FIG. 4 is a diagram showing a main part of a CMP polishing apparatus according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of a main part of the device, partially cut away;

FIG. 6 is a block diagram showing main parts of a transmission unit and a reception unit incorporated in the apparatus.

FIG. 7 is a graph showing a distribution state of each parameter in the apparatus.

FIG. 8 is a perspective view showing a conventional CMP polishing apparatus.

FIG. 9 is a sectional view showing a main part of the apparatus.

FIG. 10 is a cross-sectional view schematically showing a state of polishing by the apparatus.

FIG. 11 is a graph showing a distribution state of each parameter in the apparatus.

[Explanation of symbols]

 20, 20A CPM polishing apparatus 31 mounting table 32 control unit 40, 100 first polishing unit 50 second polishing unit 60 transport mechanism 70 accommodating unit 80 cleaning / drying unit 90 measuring unit 130 carrier unit 140: correction mechanism 150: rotating block 160: control block

Claims (8)

[Claims] A first polishing section for performing polishing by sliding an object to be polished on a first polishing cloth; a measuring section for measuring a polishing amount of the object to be polished polished by the first polishing section; A second polishing section for performing polishing by sliding the object to be polished on a second polishing cloth different from the first polishing cloth based on the polishing amount measured by the measurement section. Characteristic polishing equipment. 2. The polishing apparatus according to claim 1, wherein said second polishing cloth has a higher hardness than said first polishing cloth. 3. The object to be polished is formed of a silicon oxide material, the first polishing cloth is polyurethane foam, and the second polishing cloth is vinyl chloride resin, polyethylene, polystyrene,
The polishing apparatus according to claim 1, wherein the polishing apparatus is made of at least one of polypropylene and acrylonitrile butadiene styrene. 4. The polishing apparatus according to claim 1, wherein said first polishing section, said measuring section, and said second polishing section are arranged on the same table. 5. A carrier for exposing and supporting a surface to be polished of a plate-like object to be polished, a polishing cloth arranged opposite to the surface to be polished, and sliding the surface to be polished and the polishing cloth. A driving unit for relatively moving the carrier and the polishing cloth along the surface to be polished so as to polish the surface to be polished; and a driving unit provided on the carrier, wherein the surface to be polished of the object to be polished is the polishing cloth. A pressure sensor for measuring a pressure distribution received from the sensor, a temperature sensor for measuring the temperature distribution of the surface to be polished, a transmitter for transmitting the measurement data measured by the pressure sensor and the temperature sensor in a non-contact manner, A control unit for receiving the measurement data transmitted from the unit via a receiving unit. 6. The control unit according to claim 1, further comprising a calculation unit configured to calculate a pressure distribution and a temperature distribution on the surface to be polished based on the measurement data received via the reception unit. Item 6. A polishing apparatus according to Item 5. 7. The polishing apparatus according to claim 1, wherein the control unit includes a polishing removal rate calculating unit that calculates a polishing removal rate distribution on the surface to be polished based on the pressure distribution and the temperature distribution calculated by the calculation unit. The polishing apparatus according to claim 6, wherein: 8. The control unit further includes a correction value calculation unit that calculates a correction value based on the polishing removal speed distribution calculated by the polishing removal speed calculation unit, wherein the carrier is controlled by the correction value calculation unit. The polishing apparatus according to claim 7, further comprising an urging unit that urges the surface to be polished toward the polishing cloth based on the calculated correction value.