JP2003031530A - Wafer-polishing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer-polishing apparatus that relieves the setting load of the wafer-polishing apparatus, and can accurately control utilities or the like by reducing the load on a host computer in the wafer-polishing apparatus, by eliminating the need for a cable for transmitting raw data from an operation section, and further simply by exchanging only a completion signal or the like. SOLUTION: A retention head 14 is equipped with an operation section for pressing a wafer 50 to a polishing pad 20, and at same time, incorporates a microcomputer 46 having a ROM, a RAM, a microprocessor, a signal I/O section, and the like for controlling the operation section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer polishing apparatus using a chemical mechanical polishing (CMP) method.

[0002]

2. Description of the Related Art A wafer polishing apparatus using CMP has a single or a plurality of operating units that are centrally controlled (process control, management, measurement, etc.) by a host computer installed separately from a processing stage. This operation unit holds or processes the wafer and observes and controls the processing state. As a specific operation unit, an air supply unit that supplies air for pressing the wafer to the polishing pad to the holding head, a cleaning water supply unit that supplies cleaning water to the holding head,
There is a control unit that controls the number of revolutions of the air supply unit, the holding head, and the platen based on a signal from an end point sensor that detects the polishing end of the wafer.

FIG. 5 is a schematic view showing the structure of a conventional wafer polishing apparatus 1. This wafer polishing apparatus 1 includes a holding head 2 that holds a wafer, a spindle 3 that transmits a rotational force to the holding head 2, a platen 5 to which a polishing pad 4 is attached, a host computer 6, and an operating unit such as air and water. It is composed of a utility section 7 for supplying.

According to this wafer polishing apparatus 1, signals from all the sensors are processed by the host computer, calculations are performed, and then individual control signals are output to the utility section 7 and the drive section of the operating section. After the utility section 7 receives the signal, air and water are supplied to the operating section, and the regulator and the like are controlled based on the information from the supply amount detection sensor to feedback control the supply amount.

[0005]

However, in the conventional wafer polishing apparatus 1 described above, even if the closed loop control as shown in FIG. If for some reason there is a change between the
The drawback was that it was difficult to confirm.

That is, in the conventional wafer polishing apparatus 1, it is very difficult to know the state of air pressure or the like at a specific point. In addition, since all the raw data generated during the process in the operation unit is sent to the host computer 6, problems related to information transmission and problems related to information processing occur. The former is related to noise and drive design. As the amount of raw signal increases, the number of cables increases, which makes it easier for noise to be transmitted. Further, there arises a problem that the rotary joint provided on the spindle 3 becomes complicated and becomes expensive. On the other hand, in the latter, the processing time is delayed because it is necessary to simultaneously handle information of a plurality of operating units, and the configuration of the host computer 6 becomes complicated. Further, it is difficult to directly observe the emergency situation of the operation unit, and it is only possible to observe the signal processing through observation, so there is a problem that it takes time at the time of emergency stop.

Further, since the process control, response observation, and control calculation are all performed by the host computer 6,
There was also a problem of insufficient computing performance (extension of calculation time).

Further, since the utility section 7 is installed away from the operating section, it is difficult to accurately control the air pressure and the like.

The present invention has been made in view of such circumstances, and an object thereof is to provide a wafer polishing apparatus capable of solving the above-mentioned drawbacks of the conventional apparatus.

[0010]

In order to achieve the above-mentioned object, the present invention holds a wafer by a holding head, and the wafer is polished by pressing the wafer against a polishing pad via the holding head. In the polishing apparatus, the holding head is provided with an operating unit for pressing the wafer against the polishing pad, and a built-in microcomputer for controlling the operating unit.

According to a second aspect of the present invention, the wafer polishing apparatus has a host computer installed outside the holding head, and the host computer and the microcomputer are communicably connected to each other. It is characterized by that.

According to the third aspect of the present invention, the microcomputer has a data input / output unit connected to the data interface unit of the host computer, and is input from the host computer via the data input / output unit. A storage unit that stores data for controlling the operation unit;
And an arithmetic circuit unit that calculates the data stored in the storage unit and outputs a control signal to the operation unit.

According to a fourth aspect of the present invention, the host computer outputs a process start signal to the microcomputer contained in the holding head, and the microcomputer includes:
The operation unit is controlled based on the process start signal, and an operation completion signal is output to the host computer when the control of the operation unit is completed.

As described above, according to the present invention, the holding head includes the storage unit for storing data of the operating unit, the arithmetic circuit unit, and the microcomputer having the data input / output function. For this reason,
The load on the host computer is reduced, a cable for transferring raw data from the operation unit is not required, and only the completion signal is exchanged, so that the design load on the wafer polishing apparatus is reduced. Further, since it is not necessary to transmit the raw data signal with a long cable, the configuration is resistant to noise.
Further, since the operating part of the holding head is controlled within the holding head, the control of the utility and the like becomes accurate.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of a wafer polishing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing the overall structure of the wafer polishing apparatus 10. Wafer polishing apparatus 10 shown in FIG.
Is mainly composed of a platen 12 and a wafer holding head 14.

The platen 12 is formed in a disk shape, and a rotating shaft 16 is connected to the center of the lower surface thereof. The platen 12 is
It rotates by driving a motor 18 connected to the rotary shaft 16. A polishing pad 20 is attached to the upper surface of the platen 12, and slurry is supplied onto the polishing pad 20 from a nozzle (not shown).

The wafer holding head 14 is mainly composed of a carrier mount table 22 and a carrier plate 24 as shown in FIG. Carrier mount table 2
2 is formed in a disk shape, and the rotating shaft 22A shown in FIGS. 1 and 2 is connected to the center of the upper surface thereof. The carrier mount table 22 is rotated by driving a motor (not shown) connected to the rotary shaft 22A.

The carrier plate 24 is detachably attached to the lower surface of the carrier mount table 22. Further, when the carrier plate 24 is attached to the carrier mount table 22, the plurality of air flow paths 26, 28, 30 ... Formed in the carrier plate 24 become the plurality of air flow paths formed in the carrier mount table 22. 32, 34, 36 ...

The air flow paths 32, 34, 36, ... Extend from the carrier mount table 22 to the rotary shaft 22A, and an air pump via a rotary joint connecting the rotary shaft 22A and the rotary shaft of a motor (not shown). It is connected to the. When the air flow paths 32, 34, 36 are used as suction flow paths, a suction pump is connected instead of the air pump.

The air flow path 26 is branched into a plurality of flow paths in the carrier plate 24, and the air injection holes 26A, 26A ... Which are the outlets of the air flow paths 26 are concentric with the center axis P of the carrier plate 24 as the center. In addition, it is formed on the outside of the lower surface of the carrier plate 24.

Similarly, the air flow path 28 is branched into a plurality of flow paths in the carrier plate 24, and the air injection holes 28A, 28A ... Which are the outlets of the air flow paths 28 are concentric with the center axis P of the carrier plate 24 as the center. And is formed inside the lower surface of the carrier plate 24.

Similarly, the air flow passage 30 is branched into a plurality of flow passages in the carrier plate 24, and the air injection holes 30A, 30A ... Which are the outlets of the air flow passages 30 are concentric with the center axis P of the carrier plate 24 as the center. And on the lower surface of the carrier plate 24 between the air injection holes 28A, 28A ... And the air injection holes 26A, 26A.

On the other hand, on the carrier mount table 22, based on the measurement data by the regulators 38, 40, 42 ... And the flow meters 44, 44 ... And the flow meters 44, 44 ... Corresponding to the regulators 38, 40, 42. A microcomputer 46 for feedback controlling the regulators 38, 40, 42 ...

The regulator 38 is attached to the air passage 32, and its opening / closing amount is controlled by the microcomputer 46. As a result, the amount of compressed air injected from the air injection holes 26A, 26A ... Is controlled. The amount of air supplied from the air flow path 32 to the air flow path 26 is measured by the flow meter 44, and the measurement data is output to the microcomputer 46. The microcomputer 46 feedback-controls the regulator 38 based on prestored reference data,
The air amount is controlled to the air amount corresponding to the reference data.

The regulator 40 is attached to the air flow path 34, and its opening / closing amount is controlled by the microcomputer 46. As a result, the amount of compressed air injected from the air injection holes 28A, 28A ... Is controlled. In addition, the amount of air supplied from the air flow path 34 to the air flow path 28 is measured by another flow meter 44.
The measurement data is output to the microcomputer 46. The microcomputer 46 feedback-controls the regulator 40 based on previously stored reference data, and controls the air amount to an air amount corresponding to the reference data.

The regulator 42 is attached to the air flow path 36, and its opening / closing amount is controlled by the microcomputer 46. As a result, the amount of compressed air injected from the air injection holes 30A, 30A ... Is controlled. Further, the amount of air supplied from the air flow passage 36 to the air flow passage 30 is calculated by another flow meter 44.
The measurement data is output to the microcomputer 46. The microcomputer 46 feedback-controls the regulator 42 based on previously stored reference data, and controls the air amount to an air amount corresponding to the reference data.

In this way, the air injection holes 26A, 28A, 3
By controlling the amount of compressed air jetted from 0A, the wafer 5 facing the air jet holes 26A, 28A, 30A
Since the pressing force of 0 on the polishing pad 20 can be controlled according to the part of the wafer 50, the polishing amount of the wafer 50 can be zone-controlled.

The signal cable 43 arranged from the carrier mount table 22 via the rotary shaft 22A is
It is connected to the host computer 52 of FIG. 3 via the rotary joint described above. The reference data stored in the microcomputer 46 is created by the host computer 52 and then sent from the host computer 52 to the signal cable 43.
Is transmitted to the microcomputer 46 via.

Next, the operation of the wafer polishing apparatus 10 configured as described above will be described.

As shown in FIG. 3, the host computer 52 outputs a comprehensive control signal for starting the process to the microcomputer 46 of the holding head 14. Upon receiving the comprehensive signal, the microcomputer 46 starts control. The contents of this control include opening / closing and adjusting the output of the regulators 38, 40, 42 ... Which are the utilities 55, and sucking up the raw information of the sensor in another operation unit to calculate / store / process. As the sensor in another operation unit, the endpoint sensor 54 of FIG. 4 incorporated in the holding head 14 can be exemplified.

When the wafer polishing state by the holding head 14 reaches the programmed processing result by the signal from the end point sensor 54, the microcomputer 46 outputs a completion signal to the host computer 52 as shown in FIG. This completion signal is a signal for the overall control signal from the host computer 52.

In the microcomputer 46, the regulators 38, 4
All the information on the operating units such as 0 and 42 is managed. Therefore, an emergency situation can be sensed quickly, and an emergency stop or the like can be executed only for the operating unit. Therefore, the influence on other operating units can be extremely small. Naturally, the recovery time is also shortened. Further, the microcomputer 46 is provided with an input / output interface 56 in order to enable a large amount of data to be exchanged in an idle state of a device in which no process is performed.

FIG. 4 is a block diagram of the microcomputer 46. This microcomputer 46 has an input / output interface 5
6, a microprocessor unit (arithmetic circuit section) 58,
It is composed of a ROM 60, a RAM 62, a signal input / output unit (data input / output unit) 64, and the like.

The microprocessor 58 calculates, controls,
ROM that stores and executes input / output programs
60 stores a data list such as a process initial / improvement control pattern, and inputs / outputs the interface 5
6 rewrites / writes out data via a data interface such as 6 or the signal input / output unit 64.

The RAM 62 temporarily stores real-time data while the process is running, and transmits information to the ROM 60 as needed. The ROM 60 stores and saves this information.

The input / output interfaces 56 are means for exchanging information with the microcomputer 46. While the signal input / output unit 64 is always connected to the device in the device such as the host computer 52, the data interface becomes active only at a predetermined time. This is because a large amount of data is exchanged.

The signal input / output unit 64 is a buffer for exchanging control signals between the microcomputer 46 and the host computer 52.

Further, the microcomputer 46 is provided with a data / input / output unit (not shown), and this data / input / output unit is a buffer through which the microcomputer 46 exchanges measurement / control data of the operating unit.

By thus incorporating the microcomputer 46 in the holding head, the maintenance of the entire wafer polishing apparatus becomes easy. In addition, data management such as data log becomes easy. Further, since a plurality of complicated host computer configurations are eliminated and a compact computing device is housed in the operation part of the apparatus, the floor area of the wafer polishing apparatus is reduced. Also,
Enables fine control of emergency situations and control of equipment during emergency situations. Furthermore, since error processing can be performed individually, the downtime is reduced and the work for restoring the device can be shortened.

[0041]

As described above, according to the wafer polishing apparatus of the present invention, the holding head has a built-in storage unit for storing data of the operating unit, an arithmetic circuit unit, and a microcomputer having a data input / output function. Therefore, the load on the host computer is reduced, and a cable for transferring raw data from the observed and control operation section is not required. Further, only the completion signal and the like are exchanged, so that the load on the wafer polishing apparatus is reduced. In addition, since it is not necessary to transmit the raw data signal with a long cable, the configuration is resistant to noise. Further, since the operating part of the holding head is controlled within the holding head, the control of the utility and the like becomes accurate.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a wafer polishing apparatus according to an embodiment.

2 is a schematic diagram of a holding head of the wafer polishing apparatus shown in FIG.

FIG. 3 is a block diagram showing a circuit configuration of the holding head shown in FIG.

FIG. 4 is a block diagram showing the configuration of the wafer polishing apparatus shown in FIG.

FIG. 5 is a block diagram showing the configuration of a conventional wafer polishing apparatus.

[Explanation of symbols]

10 ... Wafer polishing apparatus, 12 ... Platen, 14 ... Wafer holding head, 20 ... Polishing pad, 22 ... Carrier mount table, 24 ... Carrier plate, 26, 2
8, 30, 32, 34, 36 ... Air flow paths, 38, 40,
42 ... Regulator, 44 ... Flowmeter, 46 ... Microcomputer,
50 ... Wafer, 52 ... Host computer, 54 ... Endpoint sensor, 56 ... Input / output interface,
58 ... Microprocessor, 60 ... ROM, 62 ... RA
M, 64 ... Signal input / output section

Claims (4)

[Claims] 1. A wafer polishing apparatus for holding a wafer by a holding head, and pressing the wafer against a polishing pad via the holding head to polish the wafer, wherein the holding head has an operation unit for pressing the wafer against the polishing pad. And a built-in microcomputer for controlling the operation unit. 2. The wafer polishing apparatus has a host computer installed outside the holding head, and the host computer and the microcomputer are communicably connected to each other. The wafer polishing apparatus described. 3. The microcomputer includes a data input / output unit connected to a data interface unit of the host computer, and data for controlling the operation unit input from the host computer via the data input / output unit. 3. The storage unit according to claim 2, further comprising: a storage unit that stores the storage unit; and a calculation circuit unit that calculates the data stored in the storage unit and outputs a control signal to the operation unit. Wafer polishing machine. 4. The host computer outputs a process start signal to the microcomputer contained in the holding head, the microcomputer controls the operation unit based on the process start signal, and controls the operation unit. 4. The wafer polishing apparatus according to claim 2, wherein an operation completion signal is output to the host computer when the process is completed.