JPH0774231A - Treatment apparatus and its usage method - Google Patents

Abstract

PURPOSE:To remove an electric charge from the back of an object to be treated by installing a switch means for grounding a push-up pin and a lower-part electrode before the object is pushed up after the object has been treated. CONSTITUTION:After a plasma treatment has been finished, a switch 50 for a power supply is turned off, the application of a high-frequency voltage to a lower-part electrode 28 is stopped, and the generation of a plasma is stopped. A switch means 54 for grounding is turned on, and the lower-part electrode 28 and push-up pins 58 are grounded via power-supply line 48 and a power- supply plate 46. An air cylinder 14 for up-and-down drive is driven, the individual push-up pins 58 are raised, four corners on the back of an LCD substrate S are brought into contact with tip parts of pin bodies 60, and the LCD substrate S is pushed up as a whole. At this time, when the LCD substrate S is separated from the lower-part electrode 28, an electric charge is generated in the LCD substrate S due to an exfoliation electrification phenomenon. However, the generated electric charge immediately escapes via the push-up pins 58 which are grounded, and it is possible to restrain the LCD substrate S from being electrified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing apparatus for performing plasma etching or film forming processing on a glass substrate or the like and a method for using the processing apparatus.

[0002]

2. Description of the Related Art Generally, various processing apparatuses are known for performing plasma etching processing or film forming processing on the surface of an LCD substrate made of a semiconductor wafer or glass. Here, a plasma processing apparatus will be described as an example of an apparatus for performing plasma processing on the surface of an LCD substrate made of glass which is a dielectric.

FIG. 5 is a schematic block diagram of a conventional plasma processing apparatus for an LCD substrate. This type of processing apparatus has a processing chamber 2
Inside, for example, a rectangular upper electrode 4 and a lower electrode 6 are arranged parallel to each other, and a rectangular LCD substrate S is mounted on the susceptor as the lower electrode 6. And either one of the upper electrode 4 or the lower electrode 6,
In the illustrated example, a high frequency power source 10 for plasma generation is connected to the lower electrode 6 via an open / close switch 8 for plasma application, and a high frequency voltage from this power source generates plasma between both electrodes. .

Further, a plurality of push-up pins 12 are provided at the four corners of the lower electrode 6 so as to pass through the lower electrode 6 so as to be capable of projecting and retracting in the vertical direction.
Up and down are commonly moved by 4. Therefore, the push-up pin 12 is moved up and down to move the LCD substrate S up and down to transfer the LCD substrate S to and from the transfer arm 16. That is, when the LCD substrate is carried into the processing chamber 2, the LCD substrate S is transferred by the transfer arm 16 to the processing chamber 2.
The inside is loaded, and the push-up pin 12 is raised to push up the LCD substrate S. Then, after the transfer arm 16 is retracted, the push-up pin 12 is lowered to mount the LCD substrate S on the lower electrode 6.

On the other hand, when the processed LCD substrate S is carried out, the reverse operation to the above is performed. That is, the LCD substrate S that has been processed by raising the push-up pin 12
Push up the carrier arm 16 in this state
The LCD substrate S is handed over to the transfer arm side by making the push-up pin 12 descend below. Then, the LCD substrate S is unloaded by retracting the transfer arm 16.

[0006]

By the way, in general, in the case of mutual metal contact, metal-insulator contact, and metal-semiconductor contact, the intermolecular force due to contact causes polarization,
It is already known that when these are peeled off, a kind of decomposition reaction occurs and a charge development, that is, a peeling and charging phenomenon occurs in a portion that cannot be completely depolarized.

However, when the processed LCD substrate S is pushed up from the lower electrode 6 by the push-up pin 12, peeling electrification occurs between the upper surface of the lower electrode 6 and the lower surface of the LCD substrate S, and the lower surface of the LCD substrate S. A charge is generated in the. Further, such a peeling and charging phenomenon occurs not only when pushing up by the push-up pin, but also when delivering the LCD substrate during transportation. For this reason, there is a problem in that particles that cause product defects are attached to the LCD substrate S, or if the electric charge is large, the element itself formed on the LCD substrate is destroyed.

Further, the LCD substrate is required to have high transparency in view of the characteristics of the product. However, when electric charges are generated on the lower surface of the LCD substrate S as described above, for example, residual gas after etching and reaction by-products are generated on the substrate. There is a problem that the back surface is adsorbed to form a film, which impairs the transparency of the substrate. Depending on the type, the film formation on the back surface of the substrate cannot be removed even in the subsequent cleaning step, and a fundamental solution is desired. It may be possible to completely exhaust the residual gas after the processing in order to eliminate the film development on the back surface of the substrate. However, in this case, it takes a lot of time to completely exhaust the gas and the throughput is lowered. Not at all. Such peeling and charging phenomenon is a problem peculiar to LCD substrates that semiconductor wafers do not have.
Now that the size has increased to about 0 cm × 40 cm, it appears remarkably, and an early solution is desired.

The present invention focuses on the above problems,
It was created to solve this effectively. An object of the present invention is to provide a processing apparatus and a method of using the processing apparatus, which can release charges on the back surface of the object to be processed.

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention has a mounting table for mounting an object to be processed made of a dielectric on a mounting surface, and carries in the object to be processed. In a processing device configured to support the object to be processed by a plurality of push-up pins capable of appearing and retracting from the side of the mounting table toward the side of the mounting surface during unloading, after the processing of the processing target, Before the object to be processed is pushed up by the push-up pin, a grounding switch means for grounding the push-up pin is provided.

[0011]

Since the present invention is configured as described above, the object to be processed made of the dielectric material, which is mounted on the mounting surface of the mounting table, is etched by, for example, plasma. Then, when carrying out the processed object,
For example, after turning off the high frequency power source for plasma generation, the push-up pins are grounded by closing the grounding switch means. After that, by raising the push-up pin, the object to be processed is separated from the mounting table and pushed up.
At the time of this separation, electric charges are generated on the back surface of the object to be processed by peeling electrification development, but this electric charge immediately escapes to the ground through the push-up pin, and the object to be processed is charged for a long time. Can be blocked.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a processing apparatus and a method of using the processing apparatus according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of a processing apparatus according to the present invention, and FIG. 2 is an enlarged view showing a structure of a push-up pin used in the apparatus shown in FIG. In this embodiment, a plasma etching apparatus will be described as an example of the processing apparatus.

As shown in the figure, a plasma etching apparatus 18 as a processing apparatus has a processing container 20 made of substantially rectangular aluminum or stainless steel whose lower end is opened. This lower end opening 12 is made of, for example, aluminum. The substrate 22 is attached in a sealable manner. When aluminum is used for the processing container 20, the surface thereof is subjected to an alumite treatment as a corrosion resistance treatment.

The inside of the processing container 20 is hermetically sealed as described above to form a processing chamber 24, and an upper electrode 26 and a lower electrode 28 as a mounting table which are parallel to each other and are opposed to each other are formed above and below the processing chamber 24. It is arranged. The distance between the upper and lower electrodes 26, 28 is set to about 80 mm, for example.

The upper electrode 26 is the surface of the mounting table 2
8A is made of alumite-treated aluminum, and it also functions as a processing gas supply header 30 which is entirely in a container shape. For this purpose, a gas supply pipe 32 is connected to the gas supply port 30A of the supply header 30. The gas supply pipe 32 has, for example, CF ₄ and O ₂ as processing gases.
The processing gas sources 34 and 36 for respectively storing the gas are respectively connected in common, and the flow rates are controlled by the first and second flow rate control valves 38 and 40 such as mass flow controllers. Further, a large number of gas ejection holes 42 communicating with the inside of the supply header 30 are formed on the entire lower surface of the upper electrode 26 so that the processing gas is ejected toward the processing chamber 24.

The lower electrode 28 is made of plate-shaped aluminum whose surface on the mounting surface 28A is anodized to a thickness of, for example, about 40 μm. LCD (Liquid Crystal Display)
y) The substrate S will be placed. This lower electrode 28
Is fixed on the substrate 22 via an insulator 44 made of, for example, ceramics, and the lower electrode 28
A power supply plate 46 is attached to the lower surface of the. This power supply plate 4
6 is, for example, 13.56 M for plasma generation via the power supply switch 50 by the power supply line 48 in an insulated state.
It is connected to a high frequency power source 52 of Hz, and by applying a high frequency voltage to the lower electrode 28 from this power source, plasma is generated between both electrodes.

A grounding switch means 54, which is a feature of the present invention, is connected in parallel to the power supply switch 50, and the lower electrode 28 is set to the ground potential by closing the switch means 54 as necessary. Is configured to get. Further, a high-frequency shield plate 56 is formed so as to cover substantially the entire lower surface of the substrate 22 made of aluminum. By grounding the shield plate 56, the substrate 22 and the processing container 20 which are electrically connected to the shield plate 56 are grounded.

A plurality of push-up pins 58 for pushing up the LCD substrate S when loading or unloading the LCD substrate S are provided below the lower electrode 28.
The push-up pins 58 are provided at the four corners of the lower electrode 28 and support the four corners of the LCD substrate at four points. As shown in FIG. 2, the push-up pin 58 is
For example, the pin body 60 is made of a conductor such as aluminum and has a diameter of about 5 mm. The tip of the pin body 60 contacts the back surface of the LCD substrate S, so that the pin body 60 is formed into a spherical shape and the lower end portion is formed. Is provided with a base portion 62 having an enlarged diameter.

The pin body 60 is vertically movable in a loosely fitted state in a pin insertion hole 62 formed through the lower electrode 28 in the vertical direction in the figure, and the lower end of the lower electrode 28 has a required length. Is configured to be able to project upward from the upper surface of the. Therefore, the pin insertion hole 62 has an enlarged lower portion and a slightly larger cross-sectional shape than the pin body 60, and is configured to move up and down in a non-contact manner with respect to the lower electrode 28. .

An auxiliary rod 64 made of a conductor extending downward is connected to the base portion 62 of the pin body 60, and the lower end portion of the auxiliary rod 64 is vertically driven by an insulator 66 such as Teflon. It is connected to the operating punch 68 of the cylinder 14 (see FIG. 1). The operating pestle 68 is commonly connected to the four push-up pins 58, and the pins 58 are simultaneously moved up and down by one vertical drive air cylinder 14.

Normally, the lower portion of the push-up pin 58 is exposed to an atmosphere of normal pressure, whereas the push-up pin 5 is exposed.
Since the processing chamber 24 above 8 is in a vacuum state, a bellows-shaped bellows 70 made of metal is used to cut off communication between them. That is, this bellows 70
A bellows housing box 74 made of a substantially cylindrical metal and airtightly connected to the lower end portion of the pin insertion hole 60 via a seal member 72 such as an O-ring is expandably accommodated. The auxiliary rod 64 communicates with the bellows 70, the upper end of the bellows 70 is hermetically connected to the base portion 62 of the pin body 60, and the lower end of the bellows 70 includes a metal auxiliary member 76 and an O-ring 78. It is airtightly attached to the bottom of the bellows storage box 74 via. Further, the lower electrode 28 and the pin body 60 are electrically connected to each other through the bellows housing box 74, the metallic auxiliary member 76 and the bellows 70, and are electrically configured to have the same potential.

Therefore, by the action of the bellows 70,
The vertical movement of the push-up pin 58 is allowed while disconnecting the communication between the atmospheric pressure atmosphere below the push-up pin 58 and the processing chamber 24. In addition, the bellows storage box 74
An insertion hole 80 through which the auxiliary rod 64 is inserted is formed in the bottom of the above, and a linear guide 82 for ensuring the linear up-and-down movement of the auxiliary rod 64 is attached to this bottom.

On the other hand, a focus ring 8 for concentrating plasma on the LCD substrate S is provided around the lower electrode 28.
4 are provided. In addition, LC is provided on the side wall of the processing container 20.
A gate ben 86 that opens and closes when the D substrate S is loaded and unloaded, and an exhaust pipe 88 connected to a vacuum pump (not shown).
Are connected. Then, the vertical drive air cylinder 14, the power feeding switch 50, and the grounding switch means 54.
And the operation of the first and second flow control valves 38, 40, etc.,
It is controlled by the control unit 90 including a microcomputer.

Next, a method of using the present invention will be described based on the above-described apparatus example. FIG. 3 is a diagram showing a flow of a carry-out process after processing the LCD substrate.
First, the gate ben 86 provided on the side portion of the processing container 20 is opened, and the LCD substrate S supported by the transfer arm 16 is carried into the processing container 20 and positioned above the lower electrode 28. Then, by driving the vertical drive air cylinder 14, the push-up pins 58 are raised, and the four corners of the LCD substrate S are pushed up by the tips of the push-up pins 58, and the transfer pins 16 are delivered.

Next, after retracting the transfer arm, each push-up pin 58 is lowered to move the pin body 60 to the lower electrode 2.
When it is positioned below the surface of 8, the LCD substrate S is mounted on the mounting surface 28A of the mounting table 28 which is the lower electrode.

Next, the inside of the processing container 20 is evacuated through the exhaust pipe 88 by driving the vacuum pump, and the LCD substrate S is carried into the processing container 20 from the load lock chamber. Then, a predetermined processing gas such as CF ₄ and O ₂ is supplied from the processing gas sources 34 and 36 by 300 SCCM and 85 SCCM, respectively, and the inside of the processing container 20 is maintained at a predetermined pressure, for example, about 350 mTorr. And
By turning on the power supply switch 50, a high-frequency voltage is applied from the high-frequency power source 52 for plasma generation to the lower electrode 28, and the processing chamber 24 between the upper electrode 26 and the lower electrode 28 is
Plasma is generated in the substrate and etching treatment is performed, for example. At this time, the power supplied from the high frequency power supply 52 is, for example, 15
It is about 00W.

When the plasma etching process is completed in this way, the process proceeds to the LCD substrate unloading process shown in FIG. In this step, the LCD substrate 28 is attached to the lower electrode 2
In order to suppress this effect as much as possible, since peeling and electrostatic development occurs when pushing up from 8, the push-up pin 58 and the lower electrode 28 are grounded prior to pushing up.

That is, first, when the plasma processing is completed in S1 in FIG. 3, the power supply switch 50 is turned off,
The application of the high frequency voltage to the lower electrode 28 is stopped to stop the plasma generation. Then, evacuation is continued for a predetermined time to exhaust the residual gas and reaction by-products in the processing container 20 to some extent or more.

Next, in S2, the grounding switch means 5
4 is turned on, and the lower electrode 28 is grounded via the power feed line 48 and the power feed plate 46. In this case, since the aluminum pin body 60 of the push-up pin 58 is electrically connected to the lower electrode 28 via the metallic bellows housing box 74, the auxiliary member 76 and the bellows 70 provided inside the bottom portion, the lower electrode 28 is connected. At the same time as 28, the pin body 60 also becomes the ground potential.
Even when a high frequency voltage is applied, the pin body 60
Has the same potential as the lower electrode 28 because it is electrically connected to the lower electrode 28, and plasma discharge does not occur between them.
Further, the auxiliary rod 66 connected to the pin body 60 is electrically insulated from the air cylinder 14 side by the insulator 66 provided at the lower end thereof, so that the high frequency power source is not short-circuited.

When the grounding of the push-up pin 58 and the lower electrode 28 is completed in this way, next, in S3, the vertical drive air cylinder 14 is driven to move each push-up pin 58 through the operating punch 68. Raise and S4
As a result, the four corners of the back surface of the LCD substrate S are brought into contact with the tips of the pin bodies 60, and the entire LCD substrate S is pushed up. At this time, when the LCD substrate S separates from the lower electrode 28, electric charges are generated on the LCD substrate S by peeling electrification development, but the generated electric charges are immediately released through the push-up pin 58 which is grounded, and the LCD substrate S It becomes possible to suppress the charging of S. In this case, when the push-up pin 58 is made of aluminum, an alumite treatment is applied to the contact portion of the pin tip with the substrate and the contact portion with the base member in order to ensure conductivity with the LCD substrate S and the like. Try not to.

Further, in this case, since the lower electrode 28 itself is also grounded in advance, when the LCD substrate S is pushed up, the LCD
The amount of electric charge itself generated on the back surface of the substrate S can also be suppressed, and the charging of the LCD substrate S can be further suppressed.
In this case, if the charge of the LCD substrate S is not sufficiently escaped, the number of the push-up pins 58 may be increased and the push-up pins 58 may be evenly distributed in the plane.

By suppressing the charging of the LCD substrate S as described above, it is possible to prevent particles from adhering to the substrate itself and also to prevent the elements on the surface of the LCD substrate from being destroyed by the charged charges. it can. Furthermore,
Since the LCD substrate S is not charged, it is possible to prevent ionized residual gas and reaction by-products from adhering to the back surface of the substrate to form a film, and prevent the transparency of the LCD substrate from being impaired. be able to.

In this way, when the pushing up of the LCD substrate S is completed, the gate ben 86 is opened in S5 to make the carrier arm intrude below the pushed up LCD substrate S, and then in S6, for vertical driving. The air cylinder 14 is driven to lower each push-up pin 58. Then, the LCD substrate S supported by the tip of the push-up pin 58 is delivered to the transfer arm side. Then, in S7, the transfer arm is retracted from the inside of the processing chamber 24 so that the processed LCD
The substrate S will be unloaded. Thereafter, similarly, an unprocessed LCD substrate is loaded and processed.

Thus, in this embodiment, the processed LCD substrate is pushed up by the push-up pins 58 to form the lower electrode 28.
Since the push-up pin 58 and the lower electrode 28 are grounded before being pushed up from above, it is possible to prevent the back surface of the LCD substrate from being charged due to the peeling charging phenomenon and various problems associated with charging. It is possible to prevent the generation of dots. Further, this type of apparatus can be easily implemented without making a significant design change by only providing the grounding switch means 54 in the conventional processing apparatus.

In the above embodiment, after the grounding switch means 54 is turned on to ground both the lower electrode and the push-up pin 58, the air cylinder 14 is driven to start the rise of the push-up pin. However, the present invention is not limited to this, and for example, the push-up pin 58 may be provided with a switch means for grounding so as to be grounded while the push-up pin is being raised.

FIG. 4 is a diagram showing the structure that operates as described above. The grounding switch means 54 has a push-up pin 58.
Metal movable contact piece 54A provided at the lower end portion of the metal auxiliary rod 64, and a metal fixed contact piece 54B which is positioned and slightly above the movable contact piece 54A and is attached and fixed to the high-frequency shield plate 56. When the auxiliary rod 64 rises, the movable contact piece 54A and the fixed contact piece 54B are formed.
The pin main body 60 and the lower electrode 28 which conducts the pin main body 60 can be grounded by contacting with. in this case,
The distance L1 between the movable contact piece 54A and the fixed contact piece 54B before operation is set to be smaller than the distance L2 between the upper end of the pin body 60 and the upper surface of the lower electrode 28, and the push-up pin 58 is raised. At this time, first, the movable contact piece 54A and the fixed contact piece 54B come into contact with each other so that the pin body 60 is grounded, and then the tip of the pin body 60 comes into contact with the back surface of the LCD substrate S. At least one of the contact pieces 54A, 54B is made flexible so as to allow the push-up pin 58 to rise even after the contact pieces 54A, 54B are in contact with each other. According to such a configuration, the opening / closing operation of the grounding switch means 54 does not need to be performed by the control unit 90, and can be performed simply in conjunction with the raising / lowering operation of the push-up pin 58, which facilitates control.

In this embodiment, the movable contact piece 54 is placed before the push-up pin 58 and the LCD substrate S come into contact with each other.
Although A and the fixed contact piece 54B are brought into contact with each other so that the push-up pin 58 is grounded, the present invention is not limited to this, and after the push-up pin 58 and the LCD substrate S come into contact with each other, the contact piece 54A,
54B may be contacted and the pin 58 may be grounded. In this case, it is considered that the amount of electric charge generated by the peeling electrification phenomenon is slightly larger than that in the previous embodiment. In this case, however, the generated electric charge is also soon thereafter transmitted via the push-up pin 58 grounded. Since it escapes immediately, it is possible to exhibit substantially the same operational effects as the previous embodiment.

Further, in this embodiment, even if the generated charges are large enough to be discharged, this discharge phenomenon does not occur when the push-up pin 58 and the LCD substrate S contact each other, but the contact pieces 54A and 54B do not contact each other. The LCD substrate S is not damaged because it is generated when the LCD substrate S comes into contact.

In the above embodiments, the case where a high frequency power source for plasma generation is applied to the lower electrode 28 has been described, but the present invention is not limited to this, and a high frequency voltage for plasma generation is applied to the upper electrode 26. Of course, it can also be applied to. In this case, since the lower electrode and the push-up pin 58 are normally grounded at all times, they are usually formed, for example, at the tip of the pin body 60 of the push-up pin 58 in order to improve conduction with the back surface of the LCD substrate. It is configured to remove the alumite coating.

The LCD substrate is not limited to a rectangular substrate, and it is needless to say that it can be applied to all objects to be processed made of a dielectric such as a quartz (quartz) wafer.
Furthermore, the present invention is not limited to the plasma etching apparatus, and can be similarly applied to other processing apparatuses such as an ion plating apparatus and a CVD apparatus.

[0041]

As described above, according to the processing apparatus and the method of using the same of the present invention, the following excellent operational effects can be exhibited. Since the push-up pin and the lower electrode are grounded prior to pushing up the object to be processed, the electric charge generated in the object to be processed by the peeling charging phenomenon can be immediately released. Therefore, it is possible not only to prevent the destruction of the device due to the adhesion of particles and the electric charge that cause defects in the product, but also to prevent the residual gas and the reaction by-products from adhering to the transparency.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a processing apparatus according to the present invention.

FIG. 2 is an enlarged view showing a structure of a push-up pin used in the processing apparatus shown in FIG.

FIG. 3 is a diagram showing a flow of a process for carrying out a target object.

FIG. 4 is an enlarged view showing a structure of a push-up pin provided with a grounding switch means.

FIG. 5 is a schematic configuration diagram showing a conventional processing apparatus.

[Explanation of symbols]

 14 Vertical Driving Air Cylinder 16 Transfer Arm 18 Plasma Etching Device (Processing Device) 20 Processing Container 24 Processing Chamber 26 Upper Electrode 28 Lower Electrode (Mounting Table) 28A Mounting Surface 50 Power Supply Switch 52 High Frequency Power Supply 54 Grounding Switch Means 58 Push-up pin 60 Pin body 64 Auxiliary rod 66 Insulator 70 Bellows 74 Bellows accommodation box 76 Metal auxiliary member 82 Linear guide S LCD substrate (processing target made of dielectric)

Claims (5)

[Claims] 1. A mounting table for mounting an object to be processed made of a dielectric on a mounting surface, and when carrying in and out the object to be processed, it is possible to project and retract from the side of the mounting table toward the side of the mounting surface. In the processing device configured to support the object to be processed by a plurality of the push-up pins, the push-up pin is grounded after the object to be processed and before the object to be pushed up by the push-up pin. A processing device comprising a grounding switch means for performing the operation. 2. The processing apparatus according to claim 1, wherein a high frequency power source for plasma generation is connected to the mounting table so as to be turned on and off. 3. The grounding switch means is provided on the push-up pin, and the grounding switch means is turned on before the push-up pin rises and its tip comes into contact with the object to be processed. The processing apparatus according to claim 1 or 2, wherein the processing apparatus is configured. 4. An object to be processed made of a dielectric material, which is placed on a placing surface of a placing table in the processing chamber, is subjected to a predetermined treatment, and is pushed up by a plurality of push-up pins penetrating the placing table to be carried out. In the method of using the processing apparatus, the grounding switch means for grounding the push-up pin is provided, and the grounding switch means is turned on before the push-up pin comes into contact with the object to be processed. A method of using a processing device, wherein the processing device is configured to be grounded. 5. The processing apparatus according to claim 4, wherein the processing is plasma processing, and the application of the high frequency voltage for plasma generation is stopped before the push-up pin is grounded. Method.