JPH03211753A - Semiconductor manufacturimg device - Google Patents

Abstract

PURPOSE:To effectively utilize or discharge the residual charge of a wafer so as to facilitate the secession of the wafer by providing a high voltage power source with a polarity changeover means, and applying positive or negative voltages to electrodes or applying homopolar voltage to the residual charge of a wafer. CONSTITUTION:When the polarity changeover means 2f and 2g change over the positive/negative poles of respective high voltage power sources 2a and 2b between output terminals 2c and 2d and an earth terminal 2e to suck a wafer 6 with an electrostatic chuck 1, the voltage is applied so that for example an electrode 1b may be positive and an electrode 1c negative. Taking the case the that the wafer 6 is RIE-processed, the wafer 6 is charged in negative, bathed in the shower of electrons being charge particles, and negative residual charge 7a stand at the surface of the wafer 6. Thereupon, negative voltage is applied to two electrodes 1b and 1c by changing over the polarity changeover means 2f and 2g. The negative charge induced in the insulating film 1a of an electrostatic chuck 1 and the residual charge 7a of the wafer 7a repel each other with Coulomb repulsive forces functioning, so the wafer 6 can easily secede.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to semiconductor manufacturing equipment, and an object of the present invention is to effectively utilize the residual charge of the wafer and eliminate the charge, thereby facilitating the removal of the wafer from the electrostatic chuck. The electrostatic chuck has an electrostatic chuck and a power supply device, and the electrostatic chuck attracts a wafer, and includes an insulating film on the attracting surface, electrodes arranged alternately under the insulating film, and The power supply device has a lead-out terminal, and the power supply device has a lead-out terminal.
The device applies a DC voltage to the electrode, and has two high-voltage power supplies, an output terminal connected to the terminal, a ground terminal, and a polarity switching means, one of which is grounded. The terminal is provided in each of the high-voltage power supplies so that the other terminal is connected to the output terminal in a polarity-switchable manner, and the polarity switching means is configured to switch the wafer An electrostatic chuck configured to apply a voltage having the same polarity as the residual charge to the electrode via the output terminal;
The electrostatic chuck includes a transfer arm and a relay, and the electrostatic chuck includes:
The transfer arm is for adsorbing the wafer and is installed inside the apparatus main body, and the transfer arm is for attaching and detaching the wafer to and from the electrostatic chuck, and is supported through the apparatus main body in an airtight manner. It has a drive unit, an arm body that is installed inside the apparatus body and pivoted to the arm drive unit so as to be able to rotate and move up and down, and a wafer tray that is provided at the tip of the arm body so as to face the electrostatic chuck. The wafer tray is electrically connected to the arm drive section, and the relay is for grounding the arm drive section, which is electrically insulated from the main body of the device, and is normally closed. The relay is configured such that when the transfer arm receives a wafer attracted to the electrostatic chuck,
The wafer tray is opened just before it comes into contact with the wafer,
In addition, the structure is such that it closes immediately after abutment.

[Industrial application field]

The present invention relates to semiconductor manufacturing equipment, and more particularly to an electrostatic chuck that allows easy removal of a tool.

The development of electronics has been remarkable in recent years, and this development is largely due to technological innovations in semiconductor devices.

In particular, the large scale and high integration of integrated circuits using silicon semiconductors is progressing extremely rapidly, and the number of elements integrated into a chip is increasing every few years in terms of memory element capacity. It has expanded four times.

Along with this, in the series of processes from silicon wafers to finished devices, production is dependent on how efficiently and stably wafers can be handled during the so-called wafer process, which is the process up to the completion of patterning. This is important from the perspective of improving sexual performance.

Wafer processing generally includes oxidation, resist processing,
Several steps such as exposure, development, etching, and impurity introduction are repeated, and the wafer is held and transported at various points during these steps.

There are various types of jigs for holding the wafer, one of which is an electrostatic chuck that utilizes the Coulomb force of electrostatic charges.

Electrostatic chucks are often used when processing wafers in vacuum equipment that cannot perform vacuum chucks using vacuum. For example, electrostatic chucks are used in RIE (reactive ion etching) processing equipment for etching processes. It is equipped and used.

[Conventional technology]

FIG. 3 is a perspective view showing an example of a device equipped with a conventional electrostatic chuck, FIG. 4 is a perspective view showing an example of the electrostatic chuck shown in FIG. 3, and FIG. -X sectional view.

In the figure, ■ is an electrostatic chuck, 3 is a transfer arm, 3a is an arm drive section, 3c is a wafer tray, 5 is an apparatus main body, and 6 is a wafer.

In FIG. 3, an apparatus main body 5 is a semiconductor manufacturing apparatus such as an RIE processing apparatus, which is a type of dry etching, and the upper part of the apparatus main body 5 is an atmospheric atmosphere, and the lower part is a processing chamber 5a.

An electrostatic chuck 1 is attached to the apparatus main body 5 facing downward, and a wafer 6 is attracted thereto and subjected to RIE processing.

On the other hand, a transfer arm 3 is installed inside the processing chamber 5a of the apparatus main body 5. This transfer arm 3 is composed of an arm drive section 3a, an arm body 3b that is pivoted by the arm drive section 3a and rotates and moves up and down, and a wafer tray 3c provided at the tip of the arm body 3b. has been done.

Then, the wafer tray 3c rotates around until it is directly below the electrostatic chuck l (then it rises and contacts the electrostatic chuck l, and the wafer 6 is passed to the electrostatic chuck l and adsorbed,
The wafer 6 held on the electrostatic chuck 1 is received.

In FIGS. 4 and 5, the electrostatic chuck 1 has a rectangular shape for attracting the workpiece of a machine tool, but it also has a shape for attracting silicon wafers, etc. is filled. The convex surface that attracts the wafer 6 is coated with an insulating film 1a having a thickness of 100 to 300 μm.

The insulating film 1a is made of, for example, a soft material that is not heat resistant, such as plastic or rubber, or a hard material that is heat resistant, such as ceramic. When the insulating film 1a is peeled off, electrodes 1b and lc are provided underneath.

The pattern shapes of the electrodes 1b and lc have various forms depending on the purpose of adsorption, such as the shape of a circle divided into two, the shape of a ninety-nine fold, etc. comb-shaped pattern electrodes 1b, lc
, are arranged alternately.

When a high DC voltage of overlay kV is applied to each terminal 1d, le, static charges are induced in the insulating film 1a, and a Coulomb force acts between the wafer 6 and the wafer 6, thereby causing adsorption.

However, for example, in RIE processing, electrostatic chuck l
When the wafer/1G to be processed is struck by charged particles 7 such as electrons, the wafer 6 itself becomes charged due to self-bias and remains as a residual charge 7a.

As a result, even if the DC voltage applied to the electrodes ib and 1c of the electrostatic chuck l is cut off, the wafer 6 is
Do not easily withdraw from the situation (this happens from time to time).

As a countermeasure for this, although not shown, if an attempt is made to mechanically remove the wafer 6 using, for example, a lift pin, the wafer 6 may crack or the wafer 6 may be removed from the electrostatic chuck.
The moment the wafer 6 is separated from the wafer 6, a peeling discharge occurs and the wafer 6 is often damaged.

[Invention or problem to be solved]

As mentioned above, when a wafer is attracted to an electrostatic chuck installed inside a semiconductor manufacturing equipment, a residual charge remains on the wafer itself when the processing process is RIE processing, etc. There was a problem that was difficult to break away from.

However, if an attempt is made to mechanically remove the wafer, there is a problem in that peeling discharge occurs and the wafer is damaged.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor manufacturing apparatus having an electrostatic chuck that allows the wafer to be easily removed by effectively utilizing or eliminating the residual charge on the wafer.

[Means to solve the problem]

The problem described above is that the electrostatic chuck has an electrostatic chuck and a power supply device, and the electrostatic chuck is for attracting a wafer, and an insulating film is disposed on the attracting surface and an insulating film is disposed alternately under the insulating film. and a terminal led out from the electrode, the power supply device applies a DC voltage to the electrode, and includes two high-voltage power supplies, an output terminal connected to the terminal,
It has a grounding terminal and a polarity switching means, and the polarity switching means is provided on each of the high voltage power supplies so that one side is connected to the grounding terminal and the other side is connected to the output terminal so that the polarity can be switched. , the polarity switching means, when the wafer adsorbed by the electrostatic chuck is detached,
A semiconductor manufacturing device configured to apply a voltage of the same polarity as the residual charge possessed by Ueno\ to an electrode via an output terminal, further comprising an electrostatic chuck, a transfer arm, and a relay, The electrostatic chuck is for adsorbing the wafer and is installed inside the apparatus main body, and the transfer arm is for attaching and detaching the wafer to the electrostatic chuck, and is airtight to the apparatus main body. an arm drive section that is supported through the device; an arm body that is installed inside the device body and pivoted to the arm drive section so as to be able to rotate and move up and down; and an arm drive section that is provided at the tip of the arm body so as to face the electrostatic chuck. and a wafer tray, the wafer tray being electrically connected to the arm drive section, and the relay grounding the arm drive section which is electrically insulated from the apparatus main body. The relay is always closed, and when the transfer arm receives a wafer attracted to an electrostatic chuck, the relay is opened immediately before the wafer tray contacts the wafer, and is closed immediately after the contact. The present invention is solved by a semiconductor manufacturing apparatus configured to make the present invention possible.

[For production]

If a wafer attracted to an electrostatic chuck is struck by charged particles, for example in RIE processing, which is a type of etching, the wafer itself becomes charged and becomes difficult to separate from the electrostatic chuck. In the first aspect of the present invention, such residual charges accumulated on the wafer are actively utilized to easily remove the wafer from the electrostatic chuck.

That is, a voltage having the same polarity as the residual charge on the wafer is applied to the electrode of the electrostatic chuck, and the wafer is separated from the electrostatic chuck by the Coulomb repulsion caused by the charges having the same polarity.

For this purpose, a polarity switching means is provided in each high voltage power supply of a DC power supply device equipped with two high voltage power supplies, and when a wafer is attracted to an electrostatic chuck, positive and negative voltages are applied to the two electrodes, and the wafer is When separating the wafer from the electrostatic chuck, a voltage of the same polarity as the residual charge of the wafer is applied to the two electrodes.

In this way, by utilizing Coulomb repulsion, the charged wafer can be easily separated from the electrostatic chuck.

Next, in the second aspect of the present invention, the residual charge accumulated on the wafer is leaked without being discharged to the wafer tray of the transfer arm that attaches and detaches the wafer to the electrostatic chuck.

In other words, the transfer arm is electrically isolated from the main body of the device,
Furthermore, the entire transfer arm consisting of the arm drive section, arm body, and wafer tray is electrically connected. The arm drive section exposed outside of the main body of the device can be grounded at all times via a relay.

On the other hand, the wafer tray is made of a material with a volume resistivity of about 106 to 10" Ωcm to prevent a sudden potential difference between the wafer and the residual charge that would cause a discharge to occur. 5iC (silicon carbide) is used as the material.

During the wafer detachment operation, the transfer arm rotates and rises to detach the wafer from the electrostatic chuck.
Immediately before the wafer tray contacts the wafers, a relay is opened to lift the entire transfer arm off the ground. Immediately after the wafer tray comes into contact with the wafer, the relay is closed to gradually leak the residual charge on the wafer from the SiC wafer tray, which has a relatively low volume resistivity.

This can prevent damage to the wafer due to discharge.

As described above, in the present invention, for a wafer that has been processed while being attracted to an electrostatic chuck and has a residual charge, the Coulomb repulsion of the residual charge is utilized, or the wafer is placed in contact with the wafer. In addition to making the volume resistivity relatively high, the transfer arm is disconnected from the ground to gradually leak residual charge, thereby preventing damage to the wafer due to detachment of the electrostatic chuck.

〔Example〕

FIG. 1 is a configuration diagram illustrating one embodiment of the present invention, and FIG. 2 is a perspective view illustrating another embodiment of the present invention.

In the figure, l is an electrostatic chuck, 2 is a power supply device, 3 is a transfer arm, 4 is a relay, 5 is an apparatus main body, and 6 is a wafer.

Example: 1 In FIG. 1, the main part of the electrostatic chuck 1 is composed of an insulating film 1a, which is the suction surface for the wafer 6, and electrodes 1b and Ic buried under the insulating film 1a. The diameter of the wafer 6 is smaller than the diameter of the wafer 6 to be attracted.

The insulating film 1a is made of a highly insulating material with a film thickness of 100 to 300 μm, for example, and a soft material such as silicone rubber or a hard material such as alumina ceramic is used, depending on the purpose.

There are various pattern shapes for the electrodes 1b and lc, but
In this case, concentric comb-like pattern electrodes 1b and lc are used.
Terminals 1d and 1e come out from the electrodes 1b and 1c, respectively, so that a high DC voltage can be applied.

On the other hand, the power supply device 2 includes two high-voltage power supplies 2a and 2b that output a DC voltage of, for example, 2 kV, and two output terminals 2c and 2d connected to the terminals 1d and le, respectively.
It is composed of polarity switching means 2f, 2g consisting of switches each having a vexel contact, and a ground terminal 2e.

Then, the polarity switching means 2[, 2g switches the positive/negative electrodes of the respective high voltage power supplies 2a, 2b between the output terminal 2C12d and the ground terminal 2e, and when the wafer 6 is attracted to the electrostatic chuck l. , for example, if electrode 1b is positive and electrode 1
A voltage is applied so that c becomes negative.

For example, when the wafer 6 is subjected to the RIE process, the wafer 6 is negatively charged by being bombarded with electrons, which are the charged particles 7, and a negative residual charge 7a is accumulated on the surface of the wafer 6. Therefore, the polarity switching means 2[, 2g are switched to apply a negative voltage to the two electrodes tb and lc as shown.

The switching of this polarity switching means 2', 2g is as follows:
It is automatically controlled by a control system (not shown).

In this way, the negative charge If induced in the insulating film 1a of the electrostatic chuck 1 and the residual charge 7a of the wafer 6 repel each other due to Coulomb repulsion, so that the wafer 6 is easily detached.

Embodiment 2 In FIG. 2, the transfer arm 3 includes an arm drive section 3a, an arm body 3b that is pivoted by the arm drive section 3a and rotates and moves up and down, and is supported at the tip of the arm body 3b. and a wafer tray 3c directly below the electrostatic chuck 1 for attaching and detaching the wafer 6 to and from the electrostatic chuck l.

The transfer arm 3 is made of Al, for example, and is electrically connected throughout, and the wafer tray 3c is made of SiC, which has a relatively low volume resistivity.

The apparatus main body 5 is, for example, the upper wall of a processing chamber 5a in which RIE is performed. The arm drive section 3a is supported through the device main body 5 so as to be electrically insulated and kept airtight by interposing a gasket 5b made of, for example, fluorine thread resin. The upper part of the arm driving part 3a protrudes into the atmosphere and can be grounded via a relay 4 which is always closed.

The arm body 3b, wafer tray 30, etc. are included in the device body 5.
is located inside.

Wafer 6 having negative residual charge 7a as in Example 1
, the transfer arm 3 is driven to move the wafer tray 3c.
1 second before the wafer tray 3c contacts the wafer 6, the relay 4 is opened to lift the entire transfer arm 3 from the ground. Then, the wafer tray 3c holds the wafer 6
The high voltage is cut off 0.2 seconds after contact with the transfer arm 3, and the relay 4 is closed to ground the entire transfer arm 3.

As a result, the residual charge 6a on the wafer 6 is removed after about one second, and no discharge that damages the wafer 6 is observed.

In this case, an RIE processing chamber is used as an example, and a concentric comb-like pattern of electrodes is used for the electrostatic chuck, but various modifications are possible.

Further, the timing of opening/closing the relay and removing static electricity can be varied in various ways depending on, for example, the amount of residual charge accumulated on the wafer, the grounding impedance of the wafer tray and the transfer arm, and the like.

〔Effect of the invention〕

As mentioned above, for wafers that have been attracted to an electrostatic chuck and are struck by charged particles during RIE processing and become charged, residual charges accumulate, and it becomes difficult for the wafer to separate from the electrostatic chuck. In the present invention, first, a voltage having the same polarity as this charge is applied to the electrostatic chuck so that the chuck is easily detached due to Coulomb repulsion.

Furthermore, the entire transfer arm that attaches and detaches wafers to and from the electrostatic chuck is insulated from the main body of the apparatus so that it can be grounded via a relay, and the wafer tray is made of SiC, which has a relatively low volume resistivity, to adjust the timing of the relay's grounding. The residual charge accumulated in the wafer is gradually removed to prevent discharge.

In this way, conventional failures such as, for example, mechanical detachment and damage to the wafer 71 or electrical discharge between the wafer tray and the wafer can be avoided.

Therefore, the present invention greatly contributes to improving the yield in semiconductor manufacturing processes.

[Brief explanation of drawings]

FIG. 1 is a block diagram explaining one embodiment of the present invention, FIG. 2 is a perspective view explaining another embodiment of the present invention, and FIG. 3 is an example of a device equipped with a conventional electrostatic chuck. 4 is a perspective view showing an example of the electrostatic chuck shown in FIG. 3; FIG. 5 is a sectional view taken along line XX in FIG. 4. In the figure, l is an electrostatic chuck, 1a is an insulating film, lb, lc are electrodes, ld, le are terminals, 2 is a power supply device,
2a and 2b are high voltage power supplies, 2C12d is an output terminal,
2e is a ground terminal, 2f and 2g are polarity switching means, 3 is a transfer arm, 3a is an arm drive unit, 3M arm body, 3c is a sea urchin/'I' lay, 4 is a relay, 5 is a device body, and 6 is a wafer. . Mikage Akira's actual threat, 1 Σ explanation, 脣 (stone 12 fig. Miba Σ Ryozu

Claims (1)

[Claims] 1) It has an electrostatic chuck (1) and a power supply device (2), the electrostatic chuck (1) is for adsorbing a wafer (6), and the electrostatic chuck (1) is for adsorbing a wafer (6). An insulating film (1a) and an insulating film (
electrodes (1b, 1c) arranged alternately under 1a);
Terminals (1d, 1e) led out from the electrodes (1b, 1c)
), and the power supply device (2) applies a DC voltage to the electrodes (1b, 1c), and includes two high-voltage power supplies (2a, 1c).
2b), an output terminal (2c, 2d) connected to the terminal (1d, 1e), a ground terminal (2e), and polarity switching means (2f, 2g), the polarity switching means (2f, 2g), one of which is the ground terminal (2e
), the other is provided in each of the high voltage power supplies (2a, 2b) such that the other is connected to the output terminal (2c, 2d) in a polarity switchable manner, and the polarity switching means (2
f, 2g), when the wafer (6) adsorbed by the electrostatic chuck (1) is removed, the wafer (6)
) output terminal (2c,
2d) A semiconductor manufacturing apparatus characterized in that a voltage is applied to the electrodes (1b, 1c) via the electrodes (1b, 1c). 2) It has an electrostatic chuck (1), a transfer arm (3), and a relay (4). The transfer arm (3) is installed in the apparatus main body (5), and the transfer arm (3) is for attaching and detaching the wafer (6) to and from the electrostatic chuck (1).
5) An arm drive section (3a) that is airtightly penetrated and supported by the
and an arm body (3b) which is installed inside the apparatus body (5) and pivotably supported by the arm drive section (3a) so as to be able to turn and rise; The wafer tray (3c) is provided to face the chuck (1), and the wafer tray (3c) is electrically connected to the arm drive section (3a). , the relay (4) is connected to the arm drive section (3) which is electrically insulated from the device main body (5).
a), which is always closed, and the relay (4) receives the wafer (6) from which the transfer arm (3) is attracted to the electrostatic chuck (1). The semiconductor manufacturing apparatus is characterized in that the wafer tray (3c) is opened immediately before it comes into contact with the wafer (6), and is closed immediately after the wafer tray (3c) comes into contact with the wafer (6).