JPH01276736A - Etching equipment - Google Patents

Abstract

PURPOSE:To keep wafers away from dust generated from a driving portion and to increase an yield of wafers, by placing the driving mechanism including a loader/unloader and a processing portion below a processed substrate. CONSTITUTION:A wafer cassette 7 is placed on a loading cassette table 8 and a wafer 1 is positioned at a specified place by a lifting and lowering mechanism 801. A multi-joint robot 9 is moved to the side of the cassette 7 and an arm 10 is inserted into a desired place under the wafer 1 and sticks to the wafer. Then, the arm 10 is taken out and the wafer 1 is placed on a vacuum chuck 11 of a prealignment portion 4 and the orientation flat is adjusted at the center of the vacuum chuck. With a load lock chamber 13 filled with inactive gas, the wafer 1 is invited to the chamber 13 by a handling arm 17a with an opening and shutting mechanism 16a opened and the pressure of the chamber is got down to a specified value. Nextly, the opening and shutting mechanism 16b is opened and the wafer 1 is carried to a processing chamber 12 by the handling arm 17. By placing the driving mechanism under the wafer, the wafer is kept from dust, etc.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to an etching apparatus.

(Prior Art) In recent years, various types of thin film etching equipment that can simplify and automate the complex manufacturing process of semiconductor devices and form fine patterns with high precision have been developed. Plasma etching devices that utilize reactive components are attracting attention. This plasma etching apparatus converts a reactive gas, such as CF4, introduced into the processing tank into plasma by applying high-frequency power to a pair of electrodes, such as high-frequency electrodes, placed in the processing tank. Etching systems, such as those that use active ingredients to etch substrates, such as semiconductor wafers, are equipped with a number of automated wafer transfer devices for loading wafers from cassettes into processing vessels. In conventional devices, when moving a cassette mounting table that stores wafers in the vertical direction, a drive mechanism for the moving device is provided near the wafers, and a drive mechanism in the processing tank as disclosed in Japanese Patent Publication No. 57-156034 is used. A drive unit for moving the upper electrode up and down was provided at the top of the processing unit.

(Problem to be Solved by the Invention) However, in VLSIs, VLSIs, etc., microscopic dust generated from the drive unit of the device that moves the cassette mounting table that stores the wafer in the vertical direction, and the upper part of the processing unit. Dust is generated from the drive unit that moves the upper electrode up and down, and the ultrafine dust that scatters downward adheres to the wafers stored in the cassettes on the cassette mounting table, and the ultrafine patterns are plasma etched in the processing section. There is a problem in that when forming with high precision, the yield becomes extremely low. The present invention seeks to provide a device that addresses the above points.

[Structure of the invention]

(Means for Solving the Problem) In an apparatus in which the substrate to be processed is transported from a loader/unloader section capable of storing a plurality of substrates to be processed to an airtight processing section and subjected to etching processing in this processing section, the loader・
The present invention is characterized in that the drive mechanism of the unloader section and the processing section is located below the substrate to be processed.

(Operation and Effect) In an apparatus in which the substrate to be processed is transported from a loader/unloader section capable of storing a plurality of substrates to be processed to an airtight processing section and subjected to etching processing in this processing section, the loader/unloader section is capable of storing multiple substrates.
By locating the drive mechanism of the unloader section and the processing section below the substrate to be processed, very little dust generated from the drive section adheres to the wafer, and the wafer can be processed without any adverse effects. This has the effect of improving yield.

(Example) Hereinafter, an example in which the present invention apparatus is applied to an etching apparatus in a semiconductor manufacturing process will be described with reference to the drawings.

A device for etching a substrate to be processed, such as a semiconductor wafer (2), such as a plasma etching device, has a storage section (2) for storing the wafer (2), a transport section (2) for carrying in and out the wafer (2) from this storage section (2), and this transport section (2). An alignment section (a) that aligns the wafer ■ from the wafer ■, a processing section 0 that etches the wafer ■ aligned with this alignment section), and an operation section 0 that performs operation settings and monitoring of each of these sections. It is configured.

The storage section (2) is capable of storing a plurality of, for example, two, wafer cassettes (2), which are capable of stacking and storing a plurality of semiconductor wafers ω, for example, 25, at predetermined intervals in the thickness direction. This wafer cassette ■ has a corresponding cassette mounting stand (
This cassette mounting table (8) can be moved up and down by an independent elevating mechanism (801) shown in FIG. 3. This elevating mechanism (801) includes, for example, a support (802) that supports a stainless steel cassette mounting table (c), and a lower end (803) of this support (802).
) is guided by a guide rod (804) and has a ball screw (805) screwed thereon that allows free movement in the vertical direction.
and a guide rod (804) are fixed. In addition, the lower end of the ball screw (805) is connected to the motor (80g) via the pulley (807), so the driving part of the lifting mechanism (801) is always connected to the cassette mounting table (80g).
) is located below. The rotation of the motor (808) is controlled by the ball screw (807) via the pulley (807).
05), and the rotation of this ball screw (805) allows the threaded support (802) to move up and down along the guide rod (804). In addition, since the center of the cassette mounting table (8) is supported by the support (802), there is less wobbling compared to the conventional cantilever structure shown in Fig. Six-stage lifting mechanism with low vibration and prevention of dust generation (
The upper outer periphery of 801) is covered with a plate-like material (809), and a plurality of openings (not shown) located on the maintenance clean room side of the housing floor plate (810) are provided. Then, air from the clean room side maintained at a higher pressure than the maintenance side clean room flows from above the cassette mounting table (8), and flows from above the lifting mechanism (801) to the bottom of the housing floor plate located on the maintenance clean room side. The water flows through the opening into the maintenance clean room. Therefore, the ball screw (805), the guide rod (804), the sliding part of the lower end of the support (803), the motor (808) part, and a part of the pulley (807), which constitute the drive mechanism of the lifting mechanism (801), Fine dust such as dust and grease is discharged into the maintenance clean room through a plurality of openings located on the maintenance clean room side of the housing floor plate. As a result, since the top of the cassette mounting table (1) is always in the clean air of the clean room side, almost no dust or the like from the drive section of the cassette vertical movement device adheres to the wafer (1). It goes without saying that similar effects can be obtained using other drive mechanisms such as a rack and pinion.

The transport section (2) is provided with an articulated robot (9) that transports the wafer (2) between the storage section (2), the alignment section (A), and the processing section (0). This articulated robot (9) is provided with an arm (10) equipped with a holding mechanism, for example, a vacuum suction mechanism (not shown).
10) is made of a material such as ceramic or quartz to prevent heavy metal contamination to the wafer ω. and,
This multi-joint robot (9) is rotatable around the - point and is further movable in the horizontal and axial directions.

A vacuum chuck (11
) is provided. This vacuum chuck (11)
The chuck is composed of a disc-shaped inner chuck and an annular outer chuck that is spaced from the outer circumference of the inner chuck by a predetermined distance.

The inner chuck can rotate around the center of the inner chuck and move up and down, and the outer chuck can move in the horizontal and axial directions. Further, a sensor, for example, a transmission type sensor, which detects the outer peripheral edge of the wafer and is movable toward the center of the inner chuck is provided.

A processing section 0 is configured to process the wafer (2) aligned with the alignment section ().

This processing section 0 has two systems, for example, an inside load lock chamber (13) and an outside load lock chamber (14), which can transport wafers while maintaining airtightness in a processing chamber (12) for etching processing. Also connected to the outside load lock chamber (13) is a preliminary chamber (15) which can be used for a wide variety of products and for various purposes, in which the processed wafers are subjected to treatments such as light etching and ashing. The inner load lock chamber (13) is provided with an opening/closing machine a (16a) on one side of the alignment section (a) side so as to form an entrance for loading the wafer (2).

The processing chamber (12) is located on the opposite surface of this opening/closing mechanism (16a).
A switch (16b) is provided to enable disconnection from the terminal.

And in this inside load lock chamber (13).

A handling arm (17a) is provided for receiving and transferring wafers from the processing chamber (12) to the alignment section. In addition, the above outside load lock chamber (14)
The processing chamber (12) is placed on one side of the processing chamber (12).
12) is provided, and an opening/closing mechanism (18a) is provided that enables isolation from the auxiliary chamber (15) adjacent to this opening/closing mechanism (18a).
) side is provided with an opening/closing mechanism (18b) that enables isolation from the preliminary chamber (15). The outer load lock chamber (14) is provided with a handling arm (17b) for receiving and transferring wafers from the reaction processing chamber (12) to the preliminary chamber (15). Each of the load lock chambers (13) and (14) is connected to a vacuum evacuation mechanism (not shown), such as a rotary pump, and is further provided with a purge mechanism (not shown) capable of introducing an inert gas, such as N2 gas.

The processing chamber (12) is made of Al and has a cylindrical interior whose surface is alumite-treated. This processing chamber (
12) Below, an electrode body (20) connected to a lifting mechanism (19) is provided so as to be able to rise and fall freely, and airtightness is maintained by a bellows (12a) made of a material such as SUS in response to this lifting and lowering. . In addition, a plurality of openings located on the maintenance clean room side are provided in the casing floor plate (810) to which this elevating mechanism (19) is attached, so that dust can be generated from the driving part (19) of the elevating mechanism. Dust and the like are discharged from the clean room side maintained at a higher pressure than the maintenance side clean room to the maintenance side clean room where the pressure is lower through a plurality of openings (811) located on the maintenance clean room side of the housing floor plate (810).

The lower electrode body (20) is, for example, made of aluminum and has a flat plate shape with an alumite-treated surface, and the upper surface of the lower electrode body (20) that holds the semiconductor wafer (2) is rounded. , which is sloped from the center to the periphery.

Further, between the lower electrode body (20) and the semiconductor wafer (2) mounting surface, there is provided an electrode that holds the semiconductor wafer (ω) and the semiconductor wafer (2), that is, the impedance between the lower electrode body (20) is made uniform. A synthetic polymer film (not shown), such as a heat-resistant polyimide resin having a thickness of about 20 μs to 100 μm, is attached to the semiconductor wafer mounting surface of the lower electrode body (20) with a heat-resistant acrylic resin adhesive. ing.

For example, four through holes (not shown) are formed in the lower electrode body (20) in the vertical direction, and a lift turbine (Z3) that can be moved up and down is provided in the through holes. This lift turbine (z3) is made of, for example, SUS, and has a plate (
24) can be raised and lowered in synchronization with the drive of the raising and lowering mechanism (25). In this case, if the lifting mechanism (25) is not driven, the plate (24) is moved by the coil spring (26).
) is urged downward by the lift turbine (2
The tip of 3) is lowered from the surface of the lower electrode body (20). Further, the through hole (22) is provided with a cooling gas flow conduit (27).
), and this cooling gas flow conduit (27) communicates with a plurality of openings (not shown), for example 16, provided on the surface of the lower electrode body (20) located at the peripheral edge of the semiconductor wafer. . A cooling gas inlet pipe (not shown) is provided at the bottom of the processing chamber (12) so that a cooling gas, such as helium gas, can be freely supplied directly to the semiconductor wafer through this opening and the through hole.

It is connected to a cooling gas supply source (not shown).

Furthermore, when applying power to the lower electrode body (20),
In order to improve the compatibility of the etching process, a cooling mechanism, for example, a flow path (30) is provided in the lower electrode body (20), and a liquid cooling system is connected to a pipe (not shown) connected to this flow path (30). A device (not shown) provides cooling means by circulating a coolant, for example a mixture of antifreeze and water. The processing chamber (1) is connected from the side of the lower electrode (14).
2) Thirty exhaust holes (32) evenly distributed at predetermined angles, for example, 10° intervals, with a diameter of, for example, five holes, in the gap up to the inner surface of
An exhaust ring (33) with a
12) The exhaust gas inside the processing chamber (12) can be freely exhausted through an exhaust pipe (34) connected to the side wall by an exhaust device (not shown), such as one in which a turbo molecular pump and a rotary pump are connected in series. A lower electrode body like this (
In order to place and fix the semiconductor wafer (20) on the semiconductor wafer (20), a clamp ring (35) is provided so as to hold down the wafer (2) when the lower electrode body (20) is raised. When the wafer ■ comes into contact with this clamp rig (35) and further raises the electrode body (20), this clamp ring (35)
is configured such that it increases by 5rNM without maintaining a predetermined pressing force. That is, this clamp ring (35).

A plurality of shafts passing through the upper part of the processing chamber (12) while maintaining a seal are made of high purity Au20. For example, 4
The book is held loose via an air cylinder (36). The clamp ring (35) is adapted to the diameter of the semiconductor wafer (2) so that the peripheral edge of the semiconductor wafer (3) comes into contact with the rounded surface of the lower electrode (20). The clamp ring (35) is made of aluminum, for example, and has an alumite-treated surface, and the alumite treatment provides an insulating alumina coating on the surface.

A processing chamber (12) facing the lower electrode body (20)
An upper electrode body (37) is provided on the upper part of the electrode body (37).

This upper electrode body (37) is made of a conductive material such as aluminum and has an alumite-treated surface, and is equipped with a cooling means. This cooling means 1, for example, forms a circulation channel (38) inside the upper electrode body (37), and is provided outside the processing chamber (12) via a pipe (not shown) connected to this channel (38). It is connected to a cooling device (not shown), and has a structure in which mixed water of antifreeze and water is controlled to a predetermined temperature and circulated. For example, an amorphous carbon upper electrode (40) is placed on the lower surface of the upper electrode body (37).
37) in an electrically connected state. A certain amount of space (41) is formed between the upper electrode (40) and the upper electrode body (37), and a gas supply pipe (42) is connected to this space (41). The pipe (42) supplies reactant gas such as CHF3, CF, etc. and carrier gas such as Ar or He from a gas supply source (not shown) outside the processing chamber (12) via a flow rate regulator (not shown), such as a mass flow controller. etc. can be freely supplied to the space (41). In addition, a plurality of baffles (43) having a plurality of openings are provided in this space (41) in order to uniformly diffuse the gas. The upper electrode (40) is arranged so that the reaction gas etc. diffused by the baffle (43) flows out into the processing chamber (12) through the upper electrode (40).
A plurality of holes (44) are formed in the hole. An insulating ring (45) is provided around the upper electrode (40) and the upper electrode body (37), and a shield extends from the lower surface of the insulating ring (45) to the peripheral edge of the lower surface of the upper electrode (40). A ring (46) is arranged. This shield ring (46) is made of an insulator such as tetrafluoroethylene resin so as to be able to generate plasma in a diameter approximately the same as that of the substrate to be etched, such as a semiconductor wafer (2). Further, a high frequency power source (47) is used to apply high frequency power to the upper electrode body (37) and the lower electrode body (20).
) is provided. An opening/closing mechanism (15a) is provided on the side of the articulated robot (15a), and in order to prevent the wafer (2) from flying up due to the pressure difference with the atmosphere when opened and closed, an exhaust mechanism (not shown) and a purge system that introduces inert gas, etc. A mechanism is provided, and a mounting table (not shown) for receiving and transferring the wafer (1) is provided so as to be movable up and down.

An operating section 0 is provided to monitor the operation settings and wafer processing status of each of the mechanisms configured above. These operating units 0 are composed of a control unit (not shown) consisting of a microcontroller, a part of memory, and an input/output unit, and are configured using software such as C language.

The above-mentioned etching apparatus is configured so that an air flow path is formed from the clean room side, which has a higher pressure than the maintenance clean room side, to the maintenance clean room side, so as to correspond to the through-the-rahole type.

I. Discussion Next, the operation of the etching apparatus described above will be explained. First, a wafer cassette ■ containing about 25 wafers is placed on the loading cassette mounting table (8) by an operator or a robot hand, and an empty wafer cassette ■ is placed on the unloading cassette mounting table (8). Place it.

Then, the wafer (2) is moved up and down by the lifting mechanism (801) and placed in a predetermined position.

At the same time, the articulated robot 0) is moved to the loading wafer cassette ■ side. And an articulated robot■)
Insert the arm (10) into the lower surface of the desired wafer (1).

Then, lower the cassette mounting table ■ by a predetermined amount, and
0) vacuum adsorbs the wafer ■.

Next, insert the arm (10) and pre-alignment section (
It is transported and placed on the vacuum chuck (11) of (b). Here, the center of the wafer (2) and the orientation flat are aligned. At this time, the inside load lock room (
In 13), an inert gas such as N2 gas is introduced and kept in a pressurized state. Then, while introducing N2 gas, open the opening/closing mechanism (16a) of the inner load lock chamber (13),
The aligned wafer (1) is transported to the inside load lock chamber by the handling arm (17a), and then the opening/closing mechanism (16a) is closed.

Then, the inside of this inner load lock chamber (13) is reduced to a predetermined pressure, for example, 0.1 to 2 Torr. At this time, the processing chamber (12) is also at a predetermined pressure, for example, I x 10".
In this state, open the opening/closing mechanism (16b) of the inner load lock chamber (13) and move the wafer ■ to the processing chamber (12) using the handling arm (17a).
Transport to. By this loading operation, the lower electrode body (20)
The lifter pin (23) is raised from the through hole (22) at a speed of, for example, 12 mm/S by driving the lifting mechanism (25). This rise causes each lifter pin (2
3) Place the wafer (■) on the upper end and bring it to a stopped state. Thereafter, the handling arm (17a) is stored in the inside load lock chamber (13), and the opening/closing mechanism (16b) is closed. Then, the lower electrode body (20) in the processing chamber (12) is raised by a predetermined amount, for example, by driving the lifting mechanism (19), so as to place the wafer (2) on the lower electrode body (20). Furthermore, while maintaining the lower position in a continuous operation, it is raised by a predetermined amount, for example, 5 nwn. As a result, the lower electrode body (20) and the upper electrode (40)
The gap is set to a predetermined interval, for example, 6 to 20 mm. During the above operation, perform exhaust control and check whether the desired gas flow and exhaust pressure are set. After that, the processing room (
12) While controlling the exhaust to maintain the inside at 2 to 3 Torr, remove the reaction gas such as CHF3 gas 11005CC or CF,
Gas 11005CC and a carrier gas such as lie gas 110005CC or Ar gas 110005CC are supplied to the upper electrode body (3) from a gas supply source through a gas supply pipe (42).
7) is uniformly rectified by a baffle (43) provided in the space (41) and flows out from the plurality of holes (44) provided in the electrode (40) to the semiconductor wafer (2). At the same time, the upper electrode (40) and the lower electrode body (
20), a high frequency power having a frequency of, for example, 13.511 I+□ is applied to turn the reaction gas into plasma, and the semiconductor wafer (2) is subjected to, for example, anisotropic etching using the reaction gas turned into plasma. At this time, the upper electrode (40) and the lower electrode body (20) become hot due to the application of high frequency power. Naturally, when the upper electrode (40) reaches a high temperature, thermal expansion occurs. In this case, since the upper electrode (40) is made of amorphous carbon and the upper electrode body (37) in contact with it is made of aluminum, the coefficients of thermal expansion are different and cracks occur. In order to prevent the occurrence of cracks, antifreeze and water are supplied from a cooling means (not shown) connected to a flow path (38) formed inside the upper electrode body (37) via a pipe (not shown). Mixed water is flowed to indirectly cool the upper electrode (40).

Furthermore, as the temperature of the lower electrode body (20) increases, the temperature of the semiconductor wafer also increases, which may destroy the resist pattern formed on the surface of the semiconductor wafer and cause defects. There is.

Therefore, like the upper electrode (40), the lower electrode body (20) is also connected to a cooling device (not shown) of another system connected to the flow path (30) formed in the lower part via piping (not shown). Cooling is achieved by flowing a mixture of antifreeze and water. This cooling water is controlled at, for example, about 0 to 60° C. in order to process the semiconductor wafer 0) at a constant temperature. In addition, since the semiconductor wafer (υ) is also heated by the thermal energy of the plasma, a plurality of openings (not shown) formed in the lower electrode body (20), for example, 16 around the periphery and 4 through holes (not shown) near the center, A cooling gas such as helium gas is supplied from a cooling gas supply source (not shown) to the back surface of the semiconductor wafer (T) through a cooling gas flow conduit (not shown) and a cooling gas introduction pipe (not shown).

At this time, the opening and the through hole are sealed by setting the semiconductor wafer (g). However, in reality, there is a minute gap between the semiconductor wafer (2) and the surface of the lower electrode body (20), and the helium gas is supplied to this gap to cool the semiconductor wafer (2). Etching is performed for a predetermined period of time, for example, 2 minutes, while considering such a situation. Then, upon completion of this process, the lower electrode body (20) is lowered while exhausting the reaction gas, etc. in the process chamber (12), and the wafer (2) is placed on the lift turbine (23). Then, the pressures in the outside load lock chamber (14) and the processing chamber (12) are brought to the same level, and the opening/closing mechanism (18b) is opened. Next, the handling arm (17b) provided in the outside load lock chamber (14) is inserted into the processing chamber (12), the lift turbine (23) is lowered, and the inside of the wafer is sucked by the handling arm (17b). Place it. Then, attach the handling arm (17b) to the outside load lock chamber (14).
) and close the opening/closing mechanism (18a). At this time, the spare room (15) has already moved to the outside load lock room (14).
The pressure is reduced to the same extent as Then, the opening/closing mechanism (18b
) is opened and the wafer (g) is stored on a mounting table (not shown) in the preliminary chamber (15) using the handling arm (17b).

Then, the opening/closing mechanism (18b) is closed, the mounting table is lowered, and the opening/closing machine 1 (15a) of the preliminary chamber (15) is opened.

Next, the multi-joint robot (2) is moved to a predetermined position in advance, the arm (10) of this multi-joint robot (2) is inserted into the preliminary chamber (15), and the wafer (2) is placed on the arm by suction. Then, the arm (10) is carried out and the opening/closing mechanism (15a) of the preliminary chamber (15) is closed. At the same time, the articulated robot ■ is moved to a predetermined position and rotated 180 degrees to place the empty cassette ■ in a predetermined position. The wafer 0) is transported and stored at the position by the arm (io). A cassette of the above series of actions.
Perform this for wafer ■ stored in .

Although the plasma etching apparatus has been described above, the present invention is applied to an LCD etching apparatus used for manufacturing screen display devices such as LCD televisions, and the drive mechanism of the unloader section and the processing section is located below the substrate to be processed. As a result, very fine dust generated from the drive section hardly adheres to the wafer, and the yield rate of wafers can be improved without any adverse effects.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an etching apparatus for explaining one embodiment of the apparatus of the present invention, FIG. 2 is an explanatory diagram of the configuration of the processing section of the apparatus shown in FIG. 1, and FIG. 3 is an explanation of the storage section of FIG. 1. 4 are explanatory diagrams of a storage section in a conventional device. 1... Wafer 2... Storage section 5... Processing section 7... Wafer cassette 8... Cassette mounting table 19... Elevating mechanism (lower electrode body) 801... Elevating mechanism patent applicant Tokyo Electron Ltd. Figure 1 (A) Figure 1 (B) Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] In an apparatus that transports the substrates to be processed from a loader/unloader section capable of storing a plurality of substrates to an airtight processing section and performs etching processing in this processing section, driving the loader/unloader section and the processing section. An etching apparatus characterized in that a mechanism is located below a substrate to be processed.