JPH06326180A - Releasing device for electrostatically attracted material - Google Patents

Abstract

PURPOSE:To provide a releasing device for an electrostatically attracted material, which positively eliminates residual electric change on the holding surface for an attracted material of an electrostatic chuck on the attracted material and safely releases the attracted material without the occurrence of the leaping of the attracted material. CONSTITUTION:An electrostatic chuck 10 attracts and holds a material to be attracted by electrostatic force. Conductive supporting pins 28 are made to penetrate the electrostatic chuck 10 and supports an attracted material 5 in a horizontal state with respect to a holding surface 35 for an attracted material of the electrostatic chuck. The pins 28 are driven up and down and electrically grounded. Conductive rubbers 30 are bonded to the supporting pins 28 with a conductive bonding agent 29 and supports the attracted material 5 through surface contact. These parts are provided in this constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for removing an electrostatic chuck.

[0002]

2. Description of the Related Art When a conventional object to be attracted, for example, a semiconductor wafer is separated from a semiconductor wafer holding surface of an electrostatic chuck that attracts and holds the semiconductor wafer by electrostatic force, the semiconductor wafer holding surface of the electrostatic chuck and the semiconductor wafer itself are charged. In order to eliminate the residual charges that have been formed, the support pins formed of a conductive material, such as aluminum, which is electrically grounded, are brought into contact with the back surface of the semiconductor wafer to remove the residual charges that have been charged on the surface of the semiconductor wafer. There is known a method in which residual charges charged on the holding surface of a semiconductor wafer of an electrostatic chuck are also discharged through the semiconductor wafer to separate the attracted body from the held surface of the electrostatic chuck.

[0003]

However, in the means for contacting the support pin formed on the back surface of the semiconductor wafer with an electrically grounded conductive material such as aluminum, the support pin is provided on the back surface of the semiconductor wafer. Since the point contact is made with the contact point, the residual charge charged on the semiconductor wafer itself and the residual charge charged on the semiconductor wafer holding portion of the electrostatic chuck cannot be completely removed by only contacting the support pin once. , It is necessary to contact the support pin with the back surface of the semiconductor wafer several times. Since the support pin is stronger than the semiconductor wafer due to the contact of the support pin,
There is a problem that the back surface of the semiconductor wafer is damaged. Further, when an insulating film such as a natural oxide film or an oxide film is formed on the back surface of the semiconductor wafer, there is a problem in that the residual charges charged on the semiconductor wafer itself are hardly removed. Further, if the residual charges charged on the semiconductor wafer itself and the residual charges charged on the semiconductor wafer holding portion of the electrostatic chuck are not completely removed, the semiconductor wafer is separated from the semiconductor wafer holding portion of the electrostatic chuck by the support pins. In doing so, if the support pins that lift the semiconductor wafer from the back surface rise above the semiconductor wafer holding portion of the electrostatic chuck, a portion where the support pins are not in contact, for example, the peripheral portion of the back surface of the semiconductor wafer, remains adsorbed by the residual charge, and The wafer itself warps, and when the support pins are further raised, the peripheral edge of the semiconductor wafer separates from the semiconductor wafer holding part of the electrostatic chuck, and at this moment, the semiconductor wafer bounces due to the recoil of the warp and hits the walls of the processing chamber, etc. There is a problem that the wafer itself is damaged.

An object of the present invention is to reliably remove the residual electric charges charged on the surface of the electrostatic chuck that holds the attracted body or the attracted body, and to safely remove the attracted body without causing the splash of the attracted body. An object is to provide a device for removing the electrostatic attraction body.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to an electrostatic chuck that attracts and holds an object to be attracted by electrostatic force, and an electrostatic chuck that penetrates the electrostatic chuck so that the object to be attracted is the object to be attracted to the electrostatic chuck. A conductive support pin that is supported in a horizontal state with respect to the holding surface and is vertically driven and is electrically grounded, and a conductive rubber that supports the attracted body in surface contact with the tip of the support pin are provided. It is composed.

[0006]

According to the present invention, since the residual charge charged on the adsorbent is brought into contact with the support pin provided with the conductive rubber in surface contact with the back surface of the adsorbent, the contact area with the adsorbent becomes large. As a result, the contact resistance with the adsorbent is reduced, and more residual charge that is charged on the adsorbent flows through the grounded conductive support pin. It is possible to more reliably remove the residual electric charge that is charged on the attracted object holding surface of the electrostatic chuck in a short time.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plasma etching apparatus to which an electrostatic chuck detachment apparatus according to an embodiment of the present invention is applied will be described below with reference to the drawings. First, the configuration of the plasma etching apparatus will be described with reference to FIGS. 1 and 2.

As shown in FIG. 1, this plasma etching apparatus includes a processing chamber 1 having airtightness, an upper electrode 2 and a lower electrode 3 for generating plasma in the processing chamber 1, and the inside of the processing chamber 1. It comprises an exhaust system 4 for reducing the pressure, and a loading / unloading system 6 for loading or unloading an object to be adsorbed, for example, a semiconductor wafer 5 into the processing chamber 1.

At least the inner wall surface of the processing chamber 1 is made of a conductor such as aluminum, and the surface of the inner wall surface is subjected to anodizing treatment. A heating means (not shown), such as a heater, for preventing the product from adhering to the inner wall surface is built in, and the heating temperature is, for example, 50 ° C to 1
The temperature can be set to an appropriate temperature within the range of 00 ° C.

The upper electrode 2 is disposed in the upper portion of the processing chamber 1, and one end of the upper electrode 2 penetrates the upper portion of the processing chamber 1 in an airtight manner, and a processing gas such as CHF is introduced into the processing chamber 1. ₃ , gas such as CF ₄ or an inert gas such as N ₂ gas is connected to the gas supply pipe 7, and the other end is connected to the gas supply pipe 7 in the direction of the semiconductor wafer 5.
Gas outlet 8 for releasing the processing gas supplied from
A plurality of holes are radially provided, and the upper electrode 2 is
It is electrically grounded by the wiring 9.

The lower electrode 3 is provided at a position facing the upper electrode 2 and has an electrostatic chuck 10 for attracting and holding the semiconductor wafer 5 by electrostatic force. The electrostatic chuck sheet 11 serving as a holding portion for holding the semiconductor wafer 5 of the electrostatic chuck 10 by suction holds an electrolytic foil copper 12 made of a conductive material from both sides with an insulating film, for example, a polyimide film 13 made of polyimide resin. Each of them is adhered with the adhesive of each of the above and is constructed into a sandwich structure. Further, the electrolytic foil copper 12 is connected to a power supply rod 14 for supplying a high voltage, for example, a voltage of 200V to 3KV to the electrolytic foil copper 12, and the power supply rod 14 is provided on the bottom surface of the processing chamber 1. It penetrates in an airtight and insulated state, and is connected to the high-voltage power supply 15 via a switching means, for example, an electromagnetic switch 16. Further, the electromagnetic switch 16 is configured to be turned on or off by a control signal of the control means 17.

Further, a susceptor 18 made of a conductive material, for example, aluminum is provided below the electrostatic chuck sheet 11, and the susceptor 18 passes through a blocking capacitor 20 to generate a high frequency wave, for example, 13.5.
It is connected to a high frequency power source 21 such as 6 MHz or 40 MHz. Further, a susceptor support base 22 is provided below the susceptor 18, and the temperature of the semiconductor wafer 5 inside the susceptor support base 22 is, for example, −30 ° C.
A coolant reservoir 20 containing a coolant, for example, liquid nitrogen, is provided to keep the temperature at −150 ° C. In the coolant reservoir 20, a coolant introduction pipe 23 for introducing liquid nitrogen and evaporation of the liquid nitrogen are provided. A refrigerant discharge pipe 24 for discharging vaporized N ₂ is connected.

Further, the susceptor 18, the susceptor support 22 and the electrostatic chuck sheet 11 transfer heat to the semiconductor wafer 5 via the electrostatic chuck sheet 11 to transfer the temperature of the coolant reservoir 20. Heat transfer medium supply passage 25 for supplying a medium, for example, He gas which is an inert gas
Has been drilled.

Further, as shown in FIG. 2, the lower electrode 3
A plurality of through holes 26 penetrating the susceptor 18 of the lower electrode 3, the susceptor support 22, the electrostatic chuck sheet 11 provided on the upper surface of the susceptor 18, and the bottom surface of the processing chamber 1, For example, three holes are provided, and inside the through hole 26, a support pin 28 formed of a conductive member and electrically grounded via an inductance 27 is provided. Furthermore, this support pin 28
On the side of the semiconductor wafer 5 that comes into contact with the semiconductor wafer 5, a conductive rubber 29, for example, a silicon rubber having a conductive rubber 30 adhered with a conductive adhesive 29, for example, an epoxy adhesive containing a silver conductive filler is used. Rubber, NBR conductive rubber, or the like is provided, and is configured to come into surface contact with the back surface of the semiconductor wafer 5. Further, the support pins 28 are fixed to a support pin support base 32 via an insulating member such as a ceramics 31, and the processing chamber 1 is provided on the peripheral edge of the support pin support base 32 and the bottom surface of the processing chamber 1. A bellows 33 that is airtight and expandable and contractible is provided between the support pin support base 32 and the support pin support base 32. The support pin support base 32 is supported by vertically moving the support pin support base 32. The pin 28 is also driven vertically,
Connected to a vertical drive means, for example, an air cylinder 34,
The support pin 28 is moved up and down by the vertical movement of the air cylinder 34, so that the semiconductor wafer 5 is placed on the holding surface 35 of the electrostatic chuck sheet 11 or released from the holding surface 35. Is configured.

As shown in FIG. 1, the exhaust system 4 is provided with a gas outlet 36 at the bottom of the processing chamber 1 for reducing the pressure inside the processing chamber 1, and the gas outlet 36 is It is configured by being connected to a vacuum exhaust device 38, for example, a turbo molecular pump via an exhaust gas pipe 37.

The loading / unloading system 6 is provided with a loading / unloading port 39 for loading / unloading the semiconductor wafer 5 on the side wall of the processing chamber 1. The loading / unloading port 39 is the gate valve 4.
This gate valve 4 is configured to open and close by 0.
A load lock chamber 41 is provided at a position facing the processing chamber 1 with 0 interposed therebetween, and a load / unload arm for loading / unloading the semiconductor wafer 5 into / from the processing chamber 1 is provided in the load lock chamber 41. 42 is provided and configured.
The plasma etching apparatus is configured as described above.

The operation of inserting and removing the semiconductor wafer 5 from the electrostatic chuck sheet 11 which is attracted and held by electrostatic force in the plasma etching apparatus configured as described above will be described.

The semiconductor wafer 5 held by the loading / unloading arm 42 is moved above the electrostatic chuck sheet 11 in the processing chamber 1, the semiconductor wafer 5 is delivered to the support pin 28, and the support pin 28 is lowered by the air cylinder 34. Then, the semiconductor wafer 5 is placed on the holding surface 35 of the electrostatic chuck sheet 11.

The holding surface 32 of the electrostatic chuck sheet 11
When the semiconductor wafer 5 is placed on the semiconductor wafer 5, the switch 16 is closed in advance, and a high voltage is supplied to the electrolytic foil copper 12 of the electrostatic chuck sheet 11, whereby the surface of the semiconductor wafer 5 is shown in FIG. As described above, the negative charge 42 is charged, the holding surface 32 of the electrostatic chuck sheet 11 is charged with the positive charge 43, and the positive charge 43 and the negative charge 42 generate an electrostatic attraction force. The semiconductor wafer 5 is attracted and held on the holding surface 35 of the electrostatic chuck sheet 11 by the electrostatic attraction force.

Next, a processing gas is introduced into the processing chamber 1 through the gas discharge port 8 to stabilize the internal pressure of the processing chamber 1 to a set value, and the heat transfer medium supply path 25 is applied to the entire back surface of the semiconductor wafer 5 to He.
Gas is supplied and processing power is supplied from the high frequency power source 21, for example, 5
0 to 2 KW is applied to generate plasma between the upper electrode 2 and the semiconductor wafer 5, and the semiconductor wafer 5 is etched by this plasma. Further, the semiconductor wafer W is pseudo-grounded due to the generation of this plasma. The attraction force of the semiconductor wafer 5 attracted to the holding surface 35 of the electrostatic chuck sheet 11 is increased.

Next, the step of separating the semiconductor wafer 5 from the holding surface 35 of the electrostatic chuck sheet 11 will be described. The He gas supplied from the heat transfer medium supply path 25 to the entire back surface of the semiconductor wafer 5 is stopped. The application of a high voltage to the electrolytic foil copper 12 of the electrostatic chuck sheet 11 is shut off by opening the switch 16. Further, as shown in FIG. 3, the support pin 28 is raised by the air cylinder 34, and the support pin 2
8 is brought into contact with the back surface of the semiconductor wafer 5 by surface contact, and the negative residual charge 42 charged on the surface of the semiconductor wafer 5 by this contact is electrically transferred through the conductive adhesive 29. It flows to the grounded support pin 28,
The static electricity is removed, and the holding surface 35 of the electrostatic chuck sheet 11 is removed.
The positive residual charge 43 that is charged in the direction also flows through the semiconductor wafer 5 to the support pin 28 that is electrically grounded, and is discharged. Then, after the charge is removed, the support pin 28 is further raised by the air cylinder 34 to separate the semiconductor wafer 5 from the holding surface 35 of the electrostatic chuck sheet 11.

The effects of this embodiment having the above-mentioned structure will be described. Residual charge on the semiconductor wafer 5 and the semiconductor wafer holding surface 35 of the electrostatic chuck sheet 11.
The residual electric charges that have been charged to the back surface of the semiconductor wafer are brought into contact with the back surface of the semiconductor wafer by surface contact, and a larger amount of the residual electric charges can be flowed to the support pin 28 that is electrically grounded to remove the electric charges. Further, since more residual charge is removed, even if the semiconductor wafer 5 is lifted above the holding surface 32 of the electrostatic chuck sheet 11, the back surface of the semiconductor wafer 5 is not adsorbed by the residual charge,
The semiconductor wafer 5 itself can be detached from the holding surface 32 of the electrostatic chuck sheet 11 while maintaining a more horizontal state without warping. Further, since the back surface of the semiconductor wafer 5 is brought into contact with a conductive rubber having a hardness lower than that of the semiconductor wafer 5, the back surface of the semiconductor wafer 5 is not damaged, and the conductive rubber increases the adhesion to the semiconductor wafer 5. By increasing the actual contact area and decreasing the contact resistance with the semiconductor wafer 5, the residual charge charged on the semiconductor wafer 5 and the electrostatic chuck sheet 1 are reduced.
It is possible to remove more of the residual charge charged on the first semiconductor wafer holding surface 35.

In the embodiment, the conductive rubber is adhered to the support pin with the conductive adhesive, but it goes without saying that the conductive rubber may be engaged with the support pin. Although the plasma etching apparatus has been described, the present invention is not limited to the plasma etching apparatus, and is also used for an apparatus that processes an object to be adsorbed by plasma such as CVD and LCD, and also a transfer device that adsorbs and transfers the object to be adsorbed by an electrostatic chuck. be able to.

[0024]

As described above, the present invention surely removes the residual charge that is charged on the surface of the electrostatic chuck to be attracted by the object to be attracted or the object to be attracted, so that the object to be attracted is held on the surface of the electrostatic chuck by the support pin. Therefore, it can be detached while maintaining the horizontal state. Therefore, there is a remarkable effect that the adsorbent can be safely separated without causing a bounce due to the warp of the adsorbent.

[0025]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a plasma etching device to which a first embodiment according to the present invention is applied.

FIG. 2 is a schematic cross-sectional view showing the action of inserting / removing the attracted body of FIG. 1 into / from the electrostatic chuck.

FIG. 3 is a partial cross-sectional view showing an effect of removing residual charges remaining on the attracted body and the electrostatic chuck of FIG.

[Explanation of sign]

 1 Processing Chamber 2 Upper Electrode 3 Lower Electrode 4 Exhaust System 5 Adsorbent (Semiconductor Wafer) 6 Loading / Unloading System 10 Electrostatic Chuck 11 Electrostatic Chuck Sheet (Adsorbent Holding Part) 28 Support Pin 29 Conductive Adhesive 30 Conductivity Rubber 35 holding surface

Claims (1)

[Claims] 1. An electrostatic chuck that attracts and holds an object to be attracted by electrostatic force, and penetrates the electrostatic chuck to support the object to be held in a horizontal state with respect to an object holding surface of the electrostatic chuck. Electrostatically characterized in that a conductive support pin that is vertically driven and electrically grounded, and a conductive rubber that supports the attracted body in surface contact with the tip of the support pin are provided. Adsorber release device.