TW201507093A - Plasma processing apparatus and clamping removal device and method thereof - Google Patents

Abstract

The invention provides a plasma processing apparatus and a clamping removal device and method thereof. The method comprises a step a of connecting a lifting device to a discharge circuit so as to remove the residual charge on the lifting device; a step b of disconnecting the lifting device and the discharge circuit; a step c of raising the lifting device to enable the lifting device to contact the bottom surface of a substrate, so that the residual charge on the substrate can be transferred to the lifting device; and a step d of lowering the lifting device to disconnect the lifting device and the back of the substrate, and connecting the lifting device again to the discharge circuit so as to remove the residual charge on the lifting device and the substrate. The invention can prevent arc discharge between the substrate and the lifting device.

Description

Plasma processing device and its removing device and method

The present invention relates to the field of semiconductor fabrication, and more particularly to a plasma processing apparatus and a de-clamping apparatus and method therefor.

In the field of semiconductor fabrication, semiconductor substrates need to be processed in a series of processes in a semiconductor processing system to form a predetermined structure, such as a plasma etching machine or a plasma chemical vapor deposition machine. In order to meet the process requirements, not only the process control process needs to be strictly controlled, but also the loading and removal of the semiconductor substrate. Loading and unclamping of semiconductor substrates is a critical step in semiconductor substrate processing.

The bottom surface of the substrate typically still has residual charge which causes the substrate to draw a suction force onto the electrostatic chuck due to static suction between the electrostatic chuck and the electrostatic chuck. Due to the limited number of lifting thimbles, it does not evenly act on the entire back of the substrate. Therefore, in some areas of the substrate where there is no lift ejector contact, the downward suction is greater than the upward thrust of the lift ejector pin, and in other parts of the substrate due to the direct contact of the lift ejector pin, the lift of the lift ejector pin is greater than With a downward suction, the cymbal will be damaged due to local distortion. Moreover, since the thrust of the lift ejector pin is a transient force, its sudden action on the substrate may cause the substrate to suddenly eject away from the electrostatic chuck, which may cause the substrate to be damaged by the elastic force. Further, due to the limited space of the plasma processing system, the above-mentioned de-clamping mechanism only takes a limited number of lifting ejector pins, and in practice, one or more of the limited lifting thimbles may be lifted due to aging of the mechanism. Incomplete or delayed or even impossible to lift, which may further cause the substrate to be tilted or lifted incompletely, causing damage to the substrate and the plasma processing substrate.

Therefore, how to remove the residual charge on the back side of the substrate during the process of clamping the substrate becomes a technical difficulty. The de-clamping process adopted by the prior art includes first stopping the process in the plasma processing chamber, then connecting the lift ejector to the discharge circuit, and finally connecting the lift ejector to the back of the substrate, however, the lift thimble is connected to the substrate. Before the back side, the back side of the substrate has a certain amount of residual charge. Since the lift ejector pin is grounded and the potential is 0, the electric potential discharge (arcing) is caused by the potential difference at the moment of contact between the two, thereby causing the back surface of the substrate. Greatly damaged.

In summary, there is a need in the industry for a safe and reliable mechanism for removing residual charge on the back side of a substrate during the clamping process to address the above-discussed deficiencies of the prior art.

In view of the above problems in the background art, the present invention proposes a plasma processing apparatus and a de-clamping apparatus and method therefor.

A first aspect of the invention provides a method for de-clamping a substrate in a plasma processing apparatus including an electrostatic chuck, wherein the plasma processing apparatus includes a base on which the substrate is placed, The base station includes an electrostatic chuck for holding the substrate for processing in the plasma processing apparatus, wherein the method comprises the following steps: Step a. Connecting the lifting device to the discharge circuit to remove Remaining charge on the lifting device; step b. disconnecting the lifting device and the discharging circuit; step c. lifting the lifting device such that the lifting device contacts the bottom surface of the substrate, Replacing the residual charge on the substrate to the lift device; step d. lowering the lift device to disconnect the lift device from the back side of the substrate, and reconnecting the lift device to the discharge circuit to remove the lift device And the residual charge on the substrate.

Further, the discharge circuit has a valve and is connected to the ground terminal or the zero potential terminal.

Further, the step a includes the step of connecting the lift device to the discharge circuit, closing the valve of the discharge circuit to conduct the remaining charge on the lift device to the ground terminal or the zero potential terminal.

Further, the step b includes the step of turning on the valve of the discharge circuit to disconnect the lift device and the discharge circuit.

Further, the step d includes the steps of: reconnecting the lift device to the discharge circuit, closing the valve of the discharge circuit to conduct residual charge on the lift device and the substrate to the ground end or the zero potential end .

Further, after performing the step c, the method further includes the step of: lifting the lifting device such that the lifting device contacts the bottom surface of the substrate to apply a first lifting force to the substrate.

Further, after performing step c, before or at the same time, the method further comprises the step of providing a gas pressure between the bottom surface of the substrate and the electrostatic chuck to apply a second lifting force to the substrate.

Further, after performing the step c, the method further includes the step of: placing a gas on the bottom surface of the substrate and the static electricity by introducing a gas into a gas injection hole provided in a bottom surface of the substrate and disposed in the electrostatic chuck A gas pressure is applied between the chucks to apply an upward second lift to the substrate.

Further, the sum of the first lift force and the second lift force is greater than or equal to a force that causes the substrate to just detach from the electrostatic chuck.

Further, the lifting device comprises one or more lifting thimbles made of a conductor material or a semiconductor material.

A second aspect of the present invention provides a de-clamping device for detaching a substrate in a plasma processing apparatus, wherein the plasma processing apparatus includes a base on which the substrate is placed, in the abutment An electrostatic chuck for holding a substrate for processing in the plasma processing apparatus includes: a lifting device movably disposed under the substrate; the discharge circuit having a valve And connected to the ground or zero potential end, wherein the valve is a triode valve or a MOS tube valve.

A third aspect of the invention provides a plasma processing apparatus characterized in that the plasma processing apparatus comprises the above-described de-griping apparatus.

The de-clamping mechanism for a plasma processing apparatus provided by the present invention can avoid arcing between the substrate and the lift ejector pin, thereby avoiding damage of the substrate due to arc discharge.

Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 is a view showing the structure of a plasma processing apparatus and a lifting apparatus. The plasma processing chamber 100 has a processing chamber (not shown), the processing chamber is substantially cylindrical, and the processing chamber sidewalls are substantially vertical, and the processing chamber has upper and lower electrodes disposed in parallel with each other. Typically, the area between the upper and lower electrodes is the processing area P which will form high frequency energy to ignite and sustain the plasma. A substrate 101 to be processed is placed over the electrostatic chuck 102, which may be a semiconductor substrate to be etched or processed or a glass plate to be processed into a flat panel display. The electrostatic chuck 102 is used to clamp the substrate 101. The reaction gas is input into the processing chamber from a gas source (not shown), and one or more RF power sources may be separately applied to the lower electrode or simultaneously applied to the upper and lower electrodes, respectively, for RF Power is delivered to the lower electrode or to the upper and lower electrodes to create a large electric field inside the processing chamber. Most of the electric field lines are contained in the processing region P between the upper electrode and the lower electrode, and this electric field accelerates a small amount of electrons existing inside the processing chamber to collide with gas molecules of the input reaction gas. These collisions result in ionization of the reactive gas and excitation of the plasma, thereby generating a plasma within the processing chamber. The neutral gas molecules of the reactive gas lose electrons when subjected to these strong electric fields, leaving positively charged ions. The positively charged ions accelerate toward the lower electrode and combine with the neutral species in the substrate being processed to excite the substrate to be processed, i.e., etched, deposited, and the like. An exhaust region is provided at a suitable location of the plasma processing chamber 100, the exhaust region being coupled to an external exhaust device (eg, a vacuum pump) for use of the spent reactant gas during processing And by-product gas extraction chamber. Wherein the plasma confinement ring is used to confine the plasma within the processing region P.

The substrate bottom surface 101a typically still has residual charge which causes the substrate to draw a negative suction force to the electrostatic chuck due to static electricity between the electrostatic chuck 102. The prior art substrate de-clamping process includes the steps of first stopping the process in the plasma processing chamber, then attaching the lift ejector to the discharge circuit, and finally attaching the lift ejector to the back of the substrate, however, in the lift thimble connection Before the back side of the substrate, the back side of the substrate has a certain amount of residual charge, and the lift thimble has a potential of 0 due to grounding. At the moment of contact between the two, the electric potential discharge (arcing) is caused by the potential difference, thereby The back of the piece caused great damage.

Based on this, the present invention proposes a method for detaching a substrate in a plasma processing apparatus including an electrostatic chuck. Referring to FIG. 1, the plasma processing apparatus 100 includes a substrate 101 placed thereon. The base station includes an electrostatic chuck 102 in the base for holding the substrate 101 for processing in the plasma processing apparatus 100.

2 is a flow chart showing the steps of a method of removing a substrate in a plasma processing apparatus in accordance with an embodiment of the present invention. The de-clamping method provided by the present invention comprises the following steps:

First, step S11 is performed to connect the lift device 103 to the discharge circuit to remove the residual charge on the lift device 103. As shown in Figure 1, in the present embodiment, the lift device 103 includes a plurality of lift pins. The discharge circuit is connected to the lift device 103, which includes a valve 104 and a ground terminal. Therefore, when the valve 104 is closed, the lifting thimble is grounded through the discharge circuit, and the grounding point is 0, so that the residual charge on the lifting ejector is guided away, and the electric charge is 0.

Then, step S12 is performed to disconnect the lift device 103 and the discharge circuit, that is, to open the valve 104.

Then, step S13 is performed to lift the lift device 103 such that the lift device 103 contacts the back surface 101a of the substrate 101 such that residual charge on the substrate 101 is transferred to the lift device 103. Since the lift device 103 and the discharge circuit are disconnected at this time, the potential is zero. It is assumed that the potential of the substrate back surface 101a at this time is 100 V, and the potential on the lift device 103 is also 100 V at this time.

Finally, step S14 is performed to lower the lift device 103 to disconnect the lift device 103 from the substrate back surface 101a, and connect the lift device 103 to the discharge circuit again, that is, close the valve 104 again to remove the lift. The residual charge on device 103 and substrate 101 is raised. At this time, even if an arc discharge occurs due to a potential difference, the arc discharge only occurs at the moment when the valve 104 is closed, and occurs at the valve 104. Since the substrate 101 and the lift device 103 are not in any connection at this time, arc discharge between the substrate 101 and the lift device is avoided.

1 is a schematic view showing the structure of a plasma processing apparatus and a lifting apparatus, wherein the plasma processing apparatus 200 is typically a plasma etching machine, which further includes an upper electrode, a lower electrode, a processing chamber, RF power supplies, matching circuits, etc., those skilled in the art will appreciate that there are solutions in the prior art that are well-used for the above-described components, and that can be used in the present invention to achieve its intended function, for the sake of brevity, no longer One by one. Further, the plasma etching machine further includes an electrostatic chuck 202, a lifting device 203, and a gas supply device 205 in a base (not shown). The electrostatic chuck 202 is used to secure a substrate 201 in a plasma etching machine, and the lifting device 203 and the air supply device 205 are used to clamp the substrate 201 from the electrostatic chuck 202.

Further, the discharge circuit has a valve 104 and is connected to the ground terminal or the zero potential terminal.

Further, the step S11 includes the following steps: the lift device 103 is connected to the discharge circuit, and the valve of the discharge circuit is closed 104 to conduct the residual charge on the lift device 103 to the ground terminal or the zero potential terminal.

Further, the step S12 includes the step of turning on the valve 104 of the discharge circuit to disconnect the lift device 103 and the discharge circuit.

Further, the step S14 includes the steps of reconnecting the lift device 103 to the discharge circuit, closing the valve 104 of the discharge circuit to conduct the residual charge on the lift device 103 and the substrate 101 to the ground. Terminal or zero potential terminal.

Optionally, after performing step S13, the method further includes the steps of: lifting the lifting device 103 such that the lifting device 103 contacts the bottom surface 101a of the substrate 101 to apply a first lifting force to the base The sheet 101 is such that the substrate 101 is detached from the base to complete the detachment.

Further, after performing the step S13, before or at the same time, the method further comprises: providing a gas pressure between the substrate bottom surface 101a and the electrostatic chuck 102 to apply a second lift to the substrate force. Wherein, the first lifting force and the second lifting force act together on the substrate 101, so that the substrate 101 is separated from the base to complete the clamping.

Further, the above steps are provided between the substrate bottom surface 101a and the electrostatic chuck 102 by introducing gas into the gas injection holes provided in the substrate bottom surface 101a and disposed in the electrostatic chuck 102. One air pressure applies an upward second lifting force to the substrate 101.

In particular, the sum of the first lift force and the second lift force is greater than or equal to the force that causes the substrate 101 to just detach from the electrostatic chuck 102.

Further, the lift device 103 includes one or more lift pins that are made of a conductor material or a semiconductor material.

A second aspect of the present invention also provides a de-clamping device for detaching a substrate 101 in a plasma processing apparatus 100, wherein the plasma processing apparatus 100 includes a base 101 on which the substrate is placed, An electrostatic chuck 102 is included in the base for holding the substrate 101 for processing in the plasma processing apparatus 100, comprising: a lifting device 103 movably disposed on the substrate The discharge circuit has a valve 104 connected to the ground end or the zero potential end, wherein the valve is a triode valve or a MOS tube valve.

The special feature of the triode valve and the MOS shut-off valve is that the opening and closing speed of the valve is controllable, and it has a certain protection current. Therefore, even if an arc discharge occurs, its protective current protects it from damage. In addition, since the switching speed is controllable, the degree of arc discharge can be appropriately reduced by adjusting the appropriate switching speed.

As for the specific functions and structures of the triode valve and the MOS shut-off valve, there is mature technical support in the prior art. Here, for the sake of brevity, we will not repeat them.

A third aspect of the present invention also provides a plasma processing apparatus 100, wherein the plasma processing apparatus 100 includes the above-described de-griping apparatus.

Although the present invention has been described in detail by the preferred embodiments thereof, it should be understood that the foregoing description should not be construed as limiting. Various modifications and alterations of the present invention will be apparent to those skilled in the art. Therefore, the scope of the invention should be defined by the appended claims.

100‧‧‧plasma processing chamber
101‧‧‧Substrate
101a‧‧‧ substrate bottom surface
102‧‧‧Electrical chuck
103‧‧‧lifting device
104‧‧‧ Valve
P‧‧‧Processing area

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing the structure of a plasma processing apparatus and a lifting apparatus; Fig. 2 is a flow chart showing the steps of a method of removing a substrate in a plasma processing apparatus according to an embodiment of the present invention.

Claims (12)

A method for detaching a substrate in a plasma processing apparatus including an electrostatic chuck, wherein the plasma processing apparatus includes a base on which the substrate is placed, and an electrostatic chuck is included in the base Removing the substrate for processing in the plasma processing apparatus, wherein the method comprises the steps of: step a. connecting the lifting device to the discharging circuit to remove the lifting device Remaining charge; step b. disconnecting the lift device and the discharge circuit; step c. lifting the lift device such that the lift device contacts the bottom surface of the substrate to cause residual charge transfer on the substrate To the lift device; Step d. Lower the lift device to disconnect the lift device from the back side of the substrate and connect the lift device to the discharge circuit again to remove residual charge on the lift device and the substrate. The method of claim 1, wherein the discharge circuit has a valve and is connected to a ground terminal or a zero potential terminal. The method of claim 2, wherein the step a comprises the steps of: the lift device is coupled to the discharge circuit, the valve of the discharge circuit is closed to direct residual charge on the lift device to the ground or Zero potential end. The method of claim 2, wherein the step b comprises the step of turning on a valve of the discharge circuit to disconnect the lift device from the discharge circuit. The method of claim 2, wherein the step d comprises the steps of: reconnecting the lift device to the discharge circuit, closing the valve of the discharge circuit to conduct residual charge on the lift device and the substrate To the ground or zero potential. The method of claim 1, wherein after performing the step c, the method further comprises the step of: lifting the lifting device such that the lifting device contacts the bottom surface of the substrate to apply a first lifting force to the Said substrate. The method of claim 6, wherein after the step c is performed, before or at the same time, the method further comprises the step of: providing a gas pressure between the bottom surface of the substrate and the electrostatic chuck to the substrate Apply a second lift. The method of claim 7, wherein after the step c is performed, the method further comprises the step of: introducing a gas into the gas jet hole facing the bottom surface of the substrate and disposed in the electrostatic chuck A gas pressure is provided between the bottom surface of the substrate and the electrostatic chuck to apply an upward second lifting force to the substrate. The method of claim 8, wherein the sum of the first lift force and the second lift force is greater than or equal to a force that causes the substrate to just detach from the electrostatic chuck. The method of claim 1, wherein the lifting device comprises one or more lifting thimbles made of a conductor material or a semiconductor material. A de-grip device for detaching a substrate in a plasma processing apparatus, wherein the plasma processing apparatus includes a base on which the substrate is placed, and an electrostatic chuck is included in the submount A process for holding a substrate for processing in the plasma processing apparatus, comprising: a lifting device movably disposed under the substrate; the discharge circuit having a valve connected to the ground or The zero potential end, wherein the valve is a triode valve or a MOS tube valve. A plasma processing apparatus, wherein the plasma processing apparatus comprises the de-clamping apparatus of claim 1.