JP5050024B2 - Substrate polishing apparatus and substrate polishing method - Google Patents

Description

  The present invention relates to a substrate polishing apparatus such as a polishing apparatus for polishing and flattening a substrate such as a semiconductor wafer, and a substrate polishing method for polishing and flattening a substrate such as a semiconductor wafer.

  In recent years, semiconductor devices have become increasingly finer and the element structure has become more complex, and as the number of layers of logic-based multilayer wiring has increased, the unevenness of the surface of the semiconductor device has increased and the level difference has a tendency to increase. This is because, in the manufacture of semiconductor devices, the process of forming a thin film, micropatterning for patterning and opening and then forming the next thin film is repeated many times.

  If the irregularities on the surface of the semiconductor device increase, the film thickness at the stepped part will become thinner during thin film formation, open due to disconnection of the wiring, short circuit due to insulation failure between wiring layers, etc. There is a tendency to decrease. In addition, even if the device normally operates normally at the beginning, a problem of reliability occurs for a long time use. Furthermore, if the irradiation surface has irregularities at the time of exposure in the lithography process, the lens focus of the exposure system becomes partially unfocused. Therefore, if the irregularities on the surface of the semiconductor device increase, it becomes difficult to form a fine pattern itself.

Accordingly, in the semiconductor device manufacturing process, a planarization technique for the surface of the semiconductor device is becoming increasingly important. Among the planarization techniques, the most important technique is chemical mechanical polishing (CMP). In this chemical mechanical polishing, a polishing apparatus containing abrasive grains such as silica (SiO ₂ ) is supplied onto a polishing surface such as a polishing pad using a polishing apparatus, and a substrate such as a semiconductor wafer is slid onto the polishing surface. Polishing in contact.

  This type of polishing apparatus includes a polishing table having a polishing surface made of a polishing pad, and a substrate holding device called a top ring or carrier head for holding a semiconductor wafer. When polishing a semiconductor wafer using such a polishing apparatus, the semiconductor wafer is pressed against the polishing table with a predetermined pressure while the semiconductor wafer is held by the substrate holding apparatus. At this time, by moving the polishing table and the substrate holding device relative to each other, the semiconductor wafer comes into sliding contact with the polishing surface, and the surface of the semiconductor wafer is polished to a flat and mirror surface.

  In the polishing apparatus described above, if the polishing rate is constant, the polishing amount is proportional to the polishing time (processing time). For this reason, the following method has been conventionally employed in determining the polishing time. That is, first, the film thickness of one semiconductor substrate before polishing is measured. Subsequently, the single semiconductor substrate is polished by a polishing apparatus for a predetermined time, and the thickness of the substrate after polishing is measured. The polishing rate is calculated from the relationship with the required polishing time, and the optimum polishing time is calculated from the relationship with the target film thickness. Then, the subsequent polishing of the semiconductor substrate is performed using the calculated polishing time (see, for example, Patent Documents 1 and 2).

  However, when the polishing rate calculated in this way is simply applied as a reference for calculating the polishing rate of the substrate to be polished next time, the polishing rate varies, and the polishing rate is limited to one sheet. In such a case, the film thickness of the substrate to be subsequently processed becomes a factor that greatly deviates from the target value. For this reason, it has been proposed to store the polishing amount and polishing time of a semiconductor substrate that has already been polished in a storage area, calculate the average polishing rate from these data, and perform the next polishing based on this average polishing time. (See Patent Document 3). The method of calculating the average polishing rate based on the past data has an effect that the labor for measuring the polishing rate for each lot can be saved and the variation in measurement can be reduced.

  However, the polishing speed in the polishing apparatus depends on the surface condition of the polishing pad, the condition of the pad conditioner that sharpens the surface of the polishing pad, the composition and supply temperature of the polishing liquid, the temperature of the film accompanying the fluctuation of temperature, pressure, and material in the film forming process. It depends strongly on non-uniformity of physical property values, fluctuations in polishing temperature, etc., and is not always stable according to the average polishing time.

Japanese Patent No. 331864 JP-A-10-106984 Japanese Examined Patent Publication No. 7-100297

  The present invention has been made in view of the above-described circumstances, and suppresses a decrease in manufacturing yield due to overpolishing and an increase in manufacturing cost due to rework (rework), and accurately polishes to a target remaining film thickness. An object of the present invention is to provide a substrate polishing apparatus and a substrate polishing method that can be used.

A substrate polishing apparatus of the present invention that solves the above problems includes a mechanism for polishing a substrate to be polished, a film thickness measuring device for measuring the thickness of a thin film formed on the substrate, and a target after polishing An interface for inputting a thin film thickness, and a control device having an arithmetic unit for calculating a polishing time and a polishing rate, the arithmetic unit comprising an upper layer thin film and a lower layer thin film formed on the substrate The polishing rate ratio of each film type, the relationship between the polishing amount and polishing time when polishing a part of the upper thin film and the lower thin film formed on the substrate, or the upper layer formed on the substrate Based on the relationship between the polishing amount and polishing time when the thin film was polished, the polishing rate of the lower layer thin film was calculated, and a means for setting the additional polishing time based on the calculated polishing rate of the lower layer thin film was provided It is characterized by.

The substrate polishing method of the present invention includes the relationship between the polishing amount and the polishing time when polishing a part of the upper thin film and the lower thin film formed on the substrate, and the upper thin film formed on the substrate. The polishing rate of the lower layer thin film is calculated from the polishing rate ratio of the respective film types of the lower layer and the lower layer, and the additional polishing time is set based on the calculated polishing rate of the lower layer thin film .
Another substrate polishing method of the present invention is the relationship between the polishing amount and polishing time when the upper thin film formed on the substrate is polished, and the upper thin film and the lower thin film formed on the substrate, respectively. The polishing rate of the lower layer thin film is calculated from the polishing rate ratio of the above film types, and the additional polishing time is set based on the calculated polishing rate of the lower layer thin film.

  According to the present invention, there are provided a substrate polishing apparatus and a substrate polishing method capable of calculating an accurate polishing rate and thereby accurately controlling a remaining film thickness.

It is a top view which shows the arrangement structure of each part of the substrate polishing apparatus which concerns on this invention. It is a partial cross section explanatory view showing a schematic structure around the polishing table. It is a block diagram which shows schematic structure of the control system of the substrate polishing apparatus. It is a figure which shows the structure of the calculating means by the weighted average method. It is a figure which shows the example of a change of the film thickness of a two-layer film. It is a figure which shows the example of a change of the film thickness of another two-layer film. Similarly, it is a figure which shows the example of a change of the film thickness of another two-layer film.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. 1-7 is a figure which shows one Embodiment based on this invention.

  FIG. 1 is a plan view showing an arrangement configuration of each part of a substrate polishing apparatus according to the present invention. The substrate polishing apparatus includes a polishing table having a polishing surface, a substrate holding device that holds a substrate to be polished and presses it against the polishing surface of the polishing table, and a film that measures the film thickness of a film formed on the substrate A thickness measuring device.

  In this substrate polishing apparatus, a transfer robot 1004 moving on a traveling rail 1003 takes out and stores a substrate such as a semiconductor wafer stocked in a cassette 1001 and also places the unpolished and polished substrate on a mounting table 1050. And it is relayed to the transport robot 1020 and reciprocated between the rotary transporter 1027. Then, the substrate on the rotary transporter 1027 is positioned on the polishing table 100 while being held on the top ring 1 of the substrate holding device described later, so that a plurality of substrates can be polished continuously. The substrate polishing apparatus is systematized. In FIG. 1, reference numerals 1005 and 1022 denote cleaning machines, which are configured to be able to clean and dry the polished substrate. Reference numeral 1036 denotes a polishing table, which is configured so that the substrate can be polished in two stages. Reference numeral 1038,3000 denotes a dresser for dressing the polishing tables 100, 1036, and reference numeral 1043 denotes a water tank for cleaning the dresser 1038.

  The substrate polishing apparatus includes an in-line film thickness measuring apparatus 200 that measures the film thickness of a semiconductor wafer or the like that has been cleaned and dried after polishing. As shown in FIG. 1, before the transfer robot 1004 stores the polished wafer in the cassette 1001, or after the transfer robot 1004 takes out the unpolished wafer from the cassette 1001 (in-line), the sensor coil is used. A conductive film of a substrate such as a semiconductor wafer from an eddy current signal, an optical signal incident and reflected on a polished surface by optical means, a temperature signal of a polished surface, or a reflected signal of a microwave alone or in an appropriate combination A film thickness measuring device (measuring means) 200 for measuring the film thickness of an insulating film such as a Cu film, a barrier layer, or an oxide film is disposed. Then, the substrate polishing apparatus can detect that the conductive film is removed except for a necessary region such as a wiring portion or the insulating film is removed during or after polishing the substrate. The measurement value is detected by monitoring, the end point of the CMP process is determined, and an appropriate polishing process can be repeated.

  Although not shown, the polishing table 100 includes an in-situ film thickness measuring device that measures the film thickness of a semiconductor wafer or the like being polished. These measurement results are transmitted to a controller, which will be described later, and used to correct operation data (recipe) of the polishing apparatus. In combination with the conditions of each polishing process in the polishing step, for example, the polishing table, the rotation speed of the top ring, the pressure, etc. By measuring the film thickness from a non-metallic thick film such as a film to a thin film and detecting a relative increase / decrease change, it is used for setting various conditions in the polishing process, for example, detecting a polishing end point. In these film thickness measuring devices, the film thickness of each region partitioned in the radial direction of the semiconductor wafer can be measured, and the pressing force applied to each region of the semiconductor wafer of the substrate holding device is the film thickness measuring device. Is adjusted based on the film thickness measurement information for each region.

  The substrate holding device of this substrate polishing apparatus is an apparatus that holds a substrate such as a semiconductor wafer to be polished as described above and presses it against the polishing surface on the polishing table for polishing. As shown in FIG. 2, a polishing table 100 having a polishing pad (polishing cloth) 101 attached to the upper surface is installed below the top ring 1 constituting the substrate holding device. A polishing liquid supply nozzle 102 is installed above the polishing table 100, and the polishing liquid Q is supplied onto the polishing pad 101 on the polishing table 100 by the polishing liquid supply nozzle 102.

  There are various types of polishing pads available on the market, such as SUBA800, IC-1000, IC-1000 / SUBA400 (double-layer cloth) manufactured by Rodel, Surfin xxx-5 manufactured by Fujimi Incorporated, Surfin 000 etc. SUBA800, Surfin xxx-5, and Surfin 000 are non-woven fabrics in which fibers are hardened with urethane resin, and IC-1000 is a hard foamed polyurethane (single layer). The polyurethane foam is porous (porous) and has a large number of fine dents or pores on its surface.

  The top ring 1 is connected to a top ring drive shaft 11 via a universal joint portion 10, and the top ring drive shaft 11 is connected to a top ring air cylinder 111 fixed to a top ring head 110. The top ring drive shaft 11 is moved up and down by the top ring air cylinder 111 to move the entire top ring 1 up and down and press the retainer ring 3 fixed to the lower end of the top ring body 2 against the polishing table 100. ing. The top ring air cylinder 111 is connected to the compressed air source 120 via the regulator RE1, and the regulator RE1 can adjust the fluid pressure such as the air pressure of the pressurized air supplied to the top ring air cylinder 111. . Thereby, the pressing force with which the retainer ring 3 presses the polishing pad 101 can be adjusted.

  The top ring drive shaft 11 is connected to the rotary cylinder 112 through a key (not shown). The rotating cylinder 112 includes a timing pulley 113 on the outer periphery thereof. A top ring motor 114 is fixed to the top ring head 110, and the timing pulley 113 is connected to a timing pulley 116 provided on the top ring motor 114 via a timing belt 115. Therefore, by rotating the top ring motor 114, the rotary cylinder 112 and the top ring drive shaft 11 are integrally rotated by the mechanism (not shown) via the timing pulley 116, the timing belt 115, and the timing pulley 113 so as to be movable up and down. The top ring 1 rotates. The top ring head 110 is supported by a top ring head shaft 117 fixedly supported on a frame (not shown).

  At the time of polishing, the suction of the semiconductor wafer W by the suction portion is released, the semiconductor wafer W is held on the lower surface of the top ring 1, and the top ring air cylinder 111 connected to the top ring drive shaft 11 is operated to operate the top ring. The retainer ring 3 fixed to the lower end of 1 is pressed against the polishing surface of the polishing table 100 with a predetermined pressing force. In this state, pressurized fluid of a predetermined pressure is supplied to the pressure chambers 22 and 23, the central pressure chamber, and the intermediate pressure chamber, respectively, and the semiconductor wafer W is pressed against the polishing surface of the polishing table 100. Then, by flowing the polishing liquid Q from the polishing liquid supply nozzle 102, the polishing liquid Q is held on the polishing pad 101, and the polishing liquid Q is interposed between the surface (lower surface) of the semiconductor wafer W to be polished and the polishing pad 101. Polishing is performed in the existing state.

On the semiconductor wafer to be polished by this substrate polishing apparatus, a copper plating film is formed in a groove provided in the SiO ₂ film in order to form a wiring, and a barrier layer is formed as the underlying material. Has been. When an insulating film such as a SiO ₂ film is formed on the uppermost layer of a semiconductor wafer to be polished by this substrate polishing apparatus, the thickness of the insulating film is detected by an optical sensor or a microwave sensor. As the light source of the optical sensor, a halogen lamp, a xenon flash lamp, an LED, a laser light source, or the like is used. In order to remove a polishing target film such as an insulating film or a conductive film in an unnecessary region (outside of a wiring region, etc.) on the semiconductor wafer, the substrate polishing apparatus uses various sensors to determine whether or not the polishing target film exists. 2, the controller 400 detects the film thickness of the film to be polished by the eddy current sensor 202 and measures the film thickness of the film to be polished by the film thickness measuring apparatus 200 while the controller 400 is on the surface of the semiconductor wafer W. Control the polishing process.

  FIG. 3 shows a schematic configuration of a control system of the substrate polishing apparatus. As described above, the polishing apparatus 301 includes a polishing unit 302 including a polishing table and a substrate holding member for polishing a substrate to be polished, a dressing unit 303 for sharpening the polishing surface of the polishing table, a cleaning unit 304, A take-out storage unit 305 for loading / unloading a semiconductor wafer from a cassette is provided. Then, the substrate taken out in the take-out storage unit 305 is sent to the polishing unit 302, the cleaning unit 304, and the like by the transport unit 306.

  The polishing apparatus 301 includes a film thickness measuring device 307, and stores data such as film thickness before and after polishing and polishing time in the storage area 308a of the control device 308. The control device 308 includes a calculation device 308b, which calculates a polishing rate from the polishing amount and polishing time of the film on the substrate after polishing, and similarly stores it in the storage area 308a. Therefore, in this polishing apparatus 301, each time the polishing is completed, the data of the removed film thickness and the polishing time are stored in the storage area 308a, the polishing speed is calculated by the arithmetic unit 308b, and the data is again stored in the storage area. It is stored in 308a. The interface 310 can input / output various data between the worker and the apparatus.

The computing device 308b includes a polishing speed computing means using a weighted average method. FIG. 4 shows a configuration example of this calculation means. The storage area 308a stores polishing rate data X ₁ , X ₂ , X ₃ , X ₄ , X ₅ ,... Of the previously polished substrate. Here, a polishing rate data X ₁ is the last of the substrate, X ₂ is a polishing rate data of the previous substrate, are arranged in order. A weighting coefficient is stored in the weighting data storage unit 308c. An appropriate numerical value is input to the weighting coefficient via the interface 310 described above. Here, in the weighting coefficients a, b, c, d, and e, a is the largest numerical value, b is smaller than a, and e is the smallest numerical value in this order. For example, a = 4, b = 2, c = 1, d = 0.5, and e = 0.25, and the weighting increases as the nearest coefficient increases. The computing device 308b includes computing means using a weighting computation method,
X ₀ = (aX ₁ + bX ₂ + cX ₃ + dX ₄ + eX ₅ ) / (a + b + c + d + e)
Is housed.

Next, a specific example of the weighted average method will be described. When the change in the polishing rate is relatively rapid, for example, when 5 wafers are polished, the polishing rate is 100 nm / min (first sheet), 105 nm / min (second sheet), 110 nm / min (third sheet). ), 115 nm / min (fourth sheet), and 120 nm / min (fifth sheet), the average polishing rate obtained by a normal average is
(100 + 105 + 110 + 115 + 120) / 5 = 110 [nm / min]
It becomes. On the other hand, the weighted average speed is
(a × 100 + b × 105 + c × 110 + d × 115 + e × 120) / (a + b + c + d + e)
As described above, the coefficient is set so as to increase in the immediate vicinity so that the immediately preceding result can be more emphasized. Thereby, the average polishing speed by the weighted average method is
(0.25 x 100 + 0.5 x 105 + 1 x 110 + 2 x 115 + 4 x 120) / (0.25 + 0.5 + 1 + 2 + 4) = 115.8 [nm / min]
It becomes. Therefore, it can be seen that the responsiveness to the most recent data is much improved.

If higher responsiveness is required, there is a method of calculating the polishing rate from the immediately preceding sheet as seen in Patent Document 1 and the like described above. However, for example, the polishing rate is
100 nm / min (first sheet),
90 nm / min (second sheet),
110 nm / min (third sheet),
100 nm / min (fourth sheet),
90 nm / min (5th sheet),
110 nm / min (sixth sheet),
If it is ..., it will vary in the range of ± 10%.

となる。このため、研磨速度の短期的な変動が生じた場合、最適研磨量との差をより増幅させてしまうことになる。 When the target polishing amount is 500 nm, the polishing time is calculated with reference to only the polishing result of the previous sheet,

It becomes. For this reason, when short-term fluctuations in the polishing rate occur, the difference from the optimum polishing amount is further amplified.

By using the weighted average method, it is possible to obtain a high responsiveness to a change in polishing rate having a long-term tendency such as a rise in the right hand, and to perform robust control that can flexibly absorb short-term fluctuations. In particular, the relationship between the polishing rate and the temperature is expressed by the following Arrhenius equation.
k = A * exp (−Ea / RT)
k: Reaction rate A: Constant R: Gas constant Ea: Activation energy T: Absolute temperature As described above, it is known that an increase in polishing temperature causes an abnormal increase in polishing rate, and is obtained by a weighted average method. The average speed can effectively contribute to the accurate calculation of the polishing time.

  Next, a method used when processing substrates in lot units will be described. The control device 308 includes means for calculating a polishing time that gives a margin (allowance, allowable range) for preventing excessive polishing from a range of past polishing speed variations. When processing a plurality of substrates in units of lots, at least the first one in the lot is not overpolished based on information on the initial film thickness, target film thickness, and past polishing rate variation range. A polishing time giving a margin is calculated, and the substrate is polished using the calculated time.

  Here, the past polishing rate variation range information means, for example, variations in the polishing rate within at least the past several lots and between lots. Note that there is also variation in one surface of the substrate to be polished, and this is obtained by averaging the measurement results at a plurality of points in the surface to obtain the polishing rate of the substrate. The margin is used to prevent overpolishing of the substrate to be polished when calculating the polishing rate for the substrate to be polished next from past data.

For example, the margin is
Polishing time of the first sheet = polishing amount / (average polishing rate × 120%)
Or = polishing amount / past maximum polishing rate or = (polishing amount × 80%) / average polishing rate.

In actual operation, it is particularly necessary in the following cases to carefully cut the first sheet in the lot.
a. When changing pads or conditioners,
b. When you replace the top ring consumables,
c. When there is a long equipment stop (idle time) between lot processing and the next lot processing.
This is because, in these states, the temperature change of the pad can occur, so that the polishing rate may change.

  Next, calibration of the film thickness measuring device will be described. This polishing apparatus 301 has a space for holding a calibration substrate having a known film thickness value. And the means which calibrates this film thickness measurement apparatus is provided for every fixed period from the space (for example, once a week or once a day). This film thickness measuring apparatus is based on the premise that the film thickness can be measured with high accuracy. For this reason, daily inspection and calibration are indispensable.

  Further, when the film thickness measuring device is an optical interference type film thickness meter or a spectroscopic Ericsson film thickness measuring device equipped with a light source typified by a tungsten halogen lamp, the amount of light decreases as the lamp life approaches. For this reason, when a decrease in the amount of light occurs, calibration is required to maintain the measurement accuracy (S / N ratio) by increasing the exposure time (integration time) during measurement. Conventionally, such inspection and calibration work has been mainly performed by an operator, but it is a very time-consuming work. As described above, in the polishing apparatus of the present invention, the calibration substrate is built in the polishing apparatus, and the calibration work is automatically performed according to the command of the control apparatus. Accurate film thickness measurement is possible.

Next, for example, polishing of a two-layer film in which the upper layer is made of a TaN film and the lower layer is made of SiO ₂ will be described. This control device is based on the polishing rate ratio of each film type of the upper layer and the lower layer or the signal from the film thickness measuring device provided in the polishing mechanism, or the polishing rate of at least one of the plurality of laminated thin films, or the layers are laminated. In addition, a means for calculating the polishing rate in each film is provided. The polishing time is optimized based on the calculated polishing rate.

For example, as shown in FIG. 5, it is assumed that the TaN film 20 nm and the SiO ₂ film 10 nm are removed by polishing for 60 seconds in the two-layer film in which the TaN film 20 nm initially exists on the lower layer film of the SiO ₂ film 50 nm. In this case, since the respective polishing rates of the SiO ₂ film / TaN film are unknown, it is not possible to calculate the optimum time for cutting the thickness of the SiO ₂ film down to 35 nm.

ここで、上記例の場合には、
ＴａＮ膜の除去膜厚 ：ｘ＝20(nm)
ＳｉＯ_２膜の除去膜厚 ：ｙ＝50-40(nm)
研磨時間 ：ｔ＝60(sec)
であるので、下記の演算により求められる。

これにより、ＳｉＯ_２膜を３５ｎｍまで研磨するのに必要な追加研磨時間は、(40-35)/0.33=15(sec)となる。 However, for example, when the ratio of the polishing rate between the TaN film and the SiO ₂ film is 2: 1, the polishing rate of the SiO ₂ film can be obtained by the following equation.
Removal thickness of TaN film: x (nm)
Removal thickness of SiO ₂ film: y (nm)
Polishing time: t (sec)

Here, in the case of the above example,
Removal thickness of TaN film: x = 20 (nm)
Removal thickness of SiO ₂ film: y = 50-40 (nm)
Polishing time: t = 60 (sec)
Therefore, it is obtained by the following calculation.

Thus, the additional polishing time required for polishing the SiO ₂ film to 35 nm is (40−35) /0.33=15 (sec).

In addition, an example in which the end point of the TaN film is acquired by a so-called in-situ monitor (such as an eddy current sensor or an optical sensor as shown in FIG. 2) that can measure the film thickness during polishing will be described. To do. As shown in FIG. 6A, when the initial film thickness is SiO ₂ film 50 nm in the lower layer and the upper layer is TaN film 20 nm, as shown in FIG. 6B, the barrier metal ( Assume that the completion of polishing of the (TaN film) is detected by an in-situ monitor. The end point was detected by an in-situ monitor after polishing for 30 seconds, and the polishing of the TaN film 20 nm was completed.
TaN film polishing rate = 20 nm / 30 sec = 0.66 (nm / sec)
Can be calculated. At this time, the SiO ₂ film is 50 nm. And since the polishing rate ratio of these two types of films is 2: 1,
Polishing rate of SiO ₂ film = (50-40) nm / 30sec = 0.33 ... (nm / sec)
Can be calculated. Therefore, the target film thickness shown in FIG. 6C is obtained by polishing for 30 seconds.

If the polishing time of the TaN film is known at the end point, the optimum polishing time can be calculated without using the selection (polishing rate) ratio. For example, it is assumed that it took 60 seconds to remove the TaN film 20 nm and the SiO ₂ film 10 nm by polishing, and that it took 30 seconds to remove the TaN film 20 nm using endpoint detection by an in-situ monitor. . Since polishing of the SiO ₂ film from 50 nm to 40 nm takes a time of (60-30) sec, the polishing rate is
(50-40) / (60-30) = 0.33… [nm / sec]
It becomes. Therefore, when the target film thickness of the SiO ₂ film is 35 nm, the additional polishing time is
(40-35) nm / 0.33 (nm / sec) = 15sec
It becomes.

Further, as shown in FIGS. 7A and 7B, for example, when an SiN film is provided with an etching groove on a Si substrate and a SiO ₂ film is deposited including the inside of the groove, When the polishing end point of the SiO ₂ film on the SiN film is detected by polishing, the required polishing time to the target film thickness of the SiN film can be calculated based on the polishing rate ratio and the endpoint monitor output. Thus, as shown in FIG. 7B, a structure (Shallow Trench Isolation) in which the SiO ₂ film is buried in the groove provided in the Si substrate and the surface is flattened (Shallow Trench Isolation) is under accurate film thickness control. It is formed.

  Although one embodiment of the present invention has been described so far, the present invention is not limited to the above-described embodiment, and needless to say, may be implemented in various forms within the scope of the technical idea. The substrate polishing apparatus and the configuration example thereof are not limited to the illustrated examples described above, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Top ring 3 Retainer ring 10 Universal joint part 11 Top ring drive shaft 22,23 Pressure chamber 100 Polishing table 101 Polishing pad 102 Polishing liquid supply nozzle 120 Compressed air source 200 Film thickness measuring apparatus 301 Polishing apparatus 302 Polishing part 303 Dressing part 304 Cleaning unit 305 Take-out storage unit 306 Transport unit 307 Film thickness measurement device 308 Control device 308a Storage area 308b Arithmetic device 310 Interface 400 Controller 1001 Cassette 1003 Travel rails 1004, 1020 Transport robot 1027 Rotary transporter 1050 Mounting table W Semiconductor wafer

Claims (3)

A mechanism for polishing a substrate to be polished, a film thickness measuring device for measuring the thickness of a thin film formed on the substrate, an interface for inputting a target thin film thickness after polishing, a polishing time and A control device having an arithmetic unit for calculating the polishing rate,
The arithmetic unit polished a polishing rate ratio of each of the upper thin film and the lower thin film formed on the substrate , and a part of the upper thin film and the lower thin film formed on the substrate. Based on the relationship between the amount of polishing and the polishing time or the relationship between the amount of polishing and the polishing time when the upper thin film formed on the substrate was polished , the polishing rate of the lower thin film was calculated and calculated A substrate polishing apparatus comprising means for setting an additional polishing time based on a polishing rate of a lower layer thin film . Relationship between polishing amount and polishing time when polishing a part of the upper layer thin film and the lower layer thin film formed on the substrate , and film types of the upper layer thin film and the lower layer thin film formed on the substrate polishing rate ratio to calculate the polishing rate of the underlying film from board polishing how to and sets the additional polishing time based on the polishing rate of the thin film of the calculated lower. Based on the relationship between the polishing amount and polishing time when the upper thin film formed on the substrate is polished, and the polishing rate ratio between the upper thin film and the lower thin film formed on the substrate , calculating a polishing rate of the thin film, board polishing how to and sets the additional polishing time based on the polishing rate of the thin film of the calculated lower.

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