JP2008311555A - Substrate treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate treatment device which enables a substrate to be uniformly treated regardless of the presence or absence of a thin film on a wafer, a thin film type and a thickness of the thin film. <P>SOLUTION: In this batch-type plasma treatment device, a plurality of stages of susceptor electrodes 50 are arranged in a treatment chamber 32 at prescribed intervals, high-frequency power is supplied by an AC source 61 to each stage of the susceptor electrode 50 for generating plasma 60, and the wafer 1 placed on each stage of the susceptor electrode 50 is subjected to plasma treatment. A silicon oxide film 51 of about 10,000 Å in thickness is formed on the surface of each stage of the susceptor electrode 50. It is possible to equalize film deposition rates between batches and in in-plane film thickness distributions since the plasma of the susceptor electrode 50 can be uniformly generated regardless of the presence or absence of a thin film on a wafer and the type and thickness of the thin film. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a substrate processing apparatus, and for example, relates to an apparatus that can be effectively used for performing plasma processing on a semiconductor wafer (hereinafter referred to as a wafer) on which a semiconductor integrated circuit device (hereinafter referred to as an IC) is manufactured.

In the IC manufacturing method, a plasma processing apparatus that performs plasma processing on a wafer is now gaining importance as a semiconductor manufacturing apparatus indispensable to the industry due to the realization of processing technology that makes use of the characteristics inherent to plasma.
In particular, a plasma apparatus using a plasma enhanced chemical vapor deposition (PECVD) method for depositing a metal film, an insulating film, and a semiconductor film on a wafer is widely used in an IC manufacturing method.
As can be understood from the fact that the electron temperature 1 eV corresponds to a temperature of about 10,000 ° C. as the ability to activate the process gas, the chemical reaction process can proceed at a relatively low temperature in the plasma.

One plasma processing apparatus using the PECVD method is disclosed in Patent Document 1.
In this method, susceptor electrodes for placing wafers one by one are arranged at predetermined intervals in a multi-stage processing chamber, and power is supplied to each susceptor electrode by a feeder to generate plasma. It is a batch type plasma processing apparatus for plasma processing a wafer placed on a susceptor electrode.
JP 2006-49367 A

  In the above-described batch type plasma processing apparatus, a silicon wafer from which a natural oxide film has been removed in advance by dilute hydrofluoric acid cleaning or the like, or a wafer in which a thin film such as an oxide film, a nitride film, or a metal film has been formed in the previous process is processed. However, depending on the presence, type, and thickness of these thin films, the impedance at the time of generating plasma by supplying high-frequency power changes, so that the film formation rate and film thickness distribution change.

  An object of the present invention is to provide a substrate processing apparatus capable of performing stable processing regardless of the presence, type, and thickness of a thin film on a substrate to be processed.

Representative inventions disclosed in the present application are as follows.
(1) A plurality of stages of susceptor electrodes on which a substrate to be processed is placed are arranged at predetermined intervals in a processing chamber, and electric power is supplied to the susceptor electrodes of each stage by a feeder to generate plasma, A substrate processing apparatus for plasma processing the substrate to be processed placed on a susceptor electrode of a stage,
An insulating film having a film thickness that absorbs fluctuations in impedance of the substrate to be processed is formed on each stage of the susceptor electrode.
(2) The substrate processing apparatus, wherein the insulating film has a thickness of about 10,000 mm.

  According to (1) above, the impedance due to the presence or absence, type and thickness variation of the thin film on the substrate to be processed can be absorbed by the insulating film formed on the surface of the susceptor electrode. It can be made uniform.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the present embodiment, the substrate processing apparatus according to the present invention is a batch type vertical hot wall type plasma processing apparatus (hereinafter referred to as a batch type plasma processing apparatus) that performs various plasma processes on a wafer in an IC manufacturing method. It is configured.
In the present embodiment, for the sake of convenience, the case where the number of wafers in one batch process is 10 has been described. However, in practice, batches of about 5 to 150 can be handled. To do.

As shown in FIGS. 1 and 2, in the batch type plasma processing apparatus 10 according to the present embodiment, a wafer carrier for storing and transporting the wafer 1 as a substrate to be processed is used as FOUP ( Hereinafter, it is referred to as a pod.) 2 is used.
The batch type plasma processing apparatus 10 according to the present embodiment includes a housing 11.
A front maintenance port 12 as an opening provided for maintenance is opened at the front front portion of the front wall 11a of the housing 11, and front maintenance doors 13 and 13 for opening and closing the front maintenance port 12 are respectively built. It is attached.
A pod loading / unloading port 14 is opened on the front wall 11a of the housing 11 so as to communicate between the inside and the outside of the housing 11, and the pod loading / unloading port 14 is opened and closed by a front shutter 15.
A load port 16 is installed on the front front side of the pod loading / unloading port 14, and the load port 16 is configured so that the pod 2 is placed and aligned.
The pod 2 is loaded onto the load port 16 by an in-process conveyance device (not shown), and is also unloaded from the load port 16.

A rotary pod shelf 17 is installed in an upper portion of the housing 11 at a substantially central portion in the front-rear direction, and the rotary pod shelf 17 is configured to store a plurality of pods 2.
That is, the rotary pod shelf 17 includes a support column 17a that is vertically set up and intermittently rotates in a horizontal plane, and a plurality of shelf plates 17b that are radially supported by the support column 17a at each of the upper, middle, and lower levels. The plurality of shelf boards 17b are configured to hold the pod 2 in a state where a plurality of pods 2 are respectively placed.
A pod transfer device 18 is installed between the load port 16 and the rotary pod shelf 17 in the housing 11. The pod carrying device 18 is composed of a pod elevator 18a and a pod carrying mechanism 18b that can be moved up and down while holding the pod 2.
The pod transfer device 18 is configured to transfer the pod 2 among the load port 16, the rotary pod shelf 17, and the pod opener 19 by continuous operation of the pod elevator 18a and the pod transfer mechanism 18b.

The pod opener 19 includes a mounting table 19a for mounting the pod 2 and a cap attaching / detaching mechanism 19b for attaching / detaching the cap of the pod 2. The pod opener 19 is configured to open and close the wafer loading / unloading port of the pod 2 by attaching / detaching the cap of the pod 2 mounted on the mounting table 19a by the cap attaching / detaching mechanism 19b.
A sub-housing 20 is constructed over the rear end at the lower part of the substantially central portion of the housing 11 in the front-rear direction. A pair of wafer loading / unloading ports 21 for loading / unloading the wafer 1 into / from the sub-casing 20 are arranged on the front wall 20a of the sub-casing 20 in two vertical rows. A pair of pod openers 19 and 19 are respectively installed at the lower wafer loading / unloading ports 21 and 21.

The sub-case 20 constitutes a transfer chamber 22 that is fluidly isolated from the installation space of the pod transfer device 18 and the rotary pod shelf 17. A wafer transfer mechanism 23 is installed in the front area of the transfer chamber 22.
The wafer transfer mechanism 23 includes a wafer transfer device 23a capable of rotating or linearly moving the wafer 1 in a horizontal plane, and a wafer transfer device elevator 23b for moving the wafer transfer device 23a up and down.
As indicated by an imaginary line in FIG. 1, the wafer transfer device elevator 23 b is installed at the right end of the front region of the transfer chamber 22 of the sub housing 20.
By the continuous operation of the wafer transfer device elevator 23b and the wafer transfer device 23a, the wafer 1 is loaded (charged) and removed (discharged) from the boat which will be described later with the tweezer 23c held by the tweezer holder of the wafer transfer device 23a. )).

In the rear area of the transfer chamber 22, a standby unit 26 that waits for the boat is configured.
A clean unit 27 composed of a supply fan and a dustproof filter is installed at the left end of the transfer chamber 22 opposite to the wafer transfer device elevator 23b. The clean unit 27 is configured to supply a clean atmosphere (air) or clean air (clean gas) 28 which is an inert gas.
Although not shown, a notch aligner for aligning the circumferential position of the wafer is installed between the wafer transfer device 23a and the clean unit 27.
The clean air 28 blown out from the clean unit 27 is circulated to a boat in the notch aligning device, the wafer transfer device 23a, and the standby unit 26, and then sucked in by a duct (not shown) and exhausted to the outside of the housing 11. Alternatively, the air is circulated to the primary side (supply side) that is the suction side of the clean unit 27, and is again blown into the transfer chamber 22 by the clean unit 27.

A processing furnace 30 is vertically installed on the upper rear side of the casing 11.
As shown in FIG. 3, the processing furnace 30 includes a process tube 31 that forms a processing chamber 32. The process tube 31 is made of a dielectric material such as quartz and is formed in a cylindrical shape with one end opened and the other end closed. The process tube 31 is vertically arranged so that the center line is vertical and is fixedly supported. ing.
The cylindrical hollow portion of the process tube 31 forms a processing chamber 32 in which a plurality of wafers 1 are accommodated, and the inner diameter of the process tube 31 is set to be larger than the maximum outer diameter of the wafer 1 to be handled.

A manifold 33 is in contact with the lower end surface of the process tube 31, and the manifold 33 is formed in a cylindrical shape having a flange projecting radially outward at both upper and lower ends using a dielectric. The manifold 33 is detachably attached to the process tube 31 for maintenance and inspection work and cleaning work on the process tube 31.
The manifold 33 is supported by the housing 11 so that the process tube 31 is installed vertically.
A lower end opening of the manifold 33 forms a furnace port 34 for taking in and out the wafer 1. The furnace port 34 is normally closed by a furnace port shutter 35.

One end of an exhaust pipe 36 is connected to the side wall of the manifold 33, and the other end of the exhaust pipe 36 is connected to an exhaust device (not shown) so that the processing chamber 32 can be exhausted.
A gas supply pipe 37 for supplying a processing gas is vertically provided at a position different from the exhaust pipe 36 of the manifold 33 (position opposite to 180 degrees in the illustrated example), and the gas supply pipe 37 is made of a dielectric. Used to form an elongated circular pipe.
A plurality of air outlets 38 are arranged in the gas supply pipe 37 so as to be arranged in the vertical direction. The number of blowout ports 38 matches the number of wafers 1 to be processed, and the height position of each blowout port 38 is set so as to face the space between adjacent wafers 1, 1 above and below. .

  A heater 39 for uniformly heating the entire processing chamber 32 is provided outside the process tube 31 in a concentric circle so as to surround the periphery of the process tube 31. It is in the state where it was installed.

As shown in FIG. 1, a boat elevator 40 is installed in the casing 11 immediately below the processing furnace 30, and as shown in FIGS. 2 and 3, an arm of the boat elevator 40 is provided. 41 is horizontally supported by a seal cap 42 for closing the furnace port 34 during processing.
The seal cap 42 is formed in a disk shape substantially equal to the outer diameter of the manifold 33, and is configured to be hermetically sealed and closed by being raised by the boat elevator 40.

On the seal cap 42, a boat 43 that holds a plurality of wafers 1 and carries it in and out of the processing chamber 32 is vertically supported and supported.
The boat 43 includes a pair of upper and lower end plates 44 and 45, and four holding pillars 46 that are installed between the both end plates 44 and 45 and arranged vertically.
Two of the four holding columns 46 are arranged separately on the left and right, and the interval between the left and right holding columns 46, 46 is set larger than the diameter of the wafer 1.
The holding column 46 is configured to also serve as a feeder that supplies power to a susceptor electrode described later. Each holding column (hereinafter referred to as an electrode column) 46 is formed using silicon carbide (SiC) as a conductive material that does not become a metal contamination source of the wafer 1.

In each electrode support 46, a plurality of susceptor electrodes 50 (11 in the present embodiment) are arranged at equal intervals in the vertical direction and held horizontally.
The interval (pitch) between the upper and lower adjacent susceptor electrodes 50, 50 is determined in consideration of the dimensions required for the transfer of the wafer 1 by the tweezer 23c of the wafer transfer device 23a and the action of plasma processing to be described later. .

As shown in FIG. 4 (a), an AC power supply 61 for applying AC power is electrically connected between matching susceptor electrodes 50, 50 in the upper and lower sides via a matching unit 62. The susceptor electrodes 50 and 50 are connected in parallel.
As the AC power, an AC power source having a low frequency from several kHz to a high frequency such as 13.56 MHz is used.

The susceptor electrode 50 is formed in a circular flat plate shape using silicon (Si) as a conductive material that does not contaminate the wafer 1 with a metal, and the outer diameter is set larger than the outer diameter of the wafer 1. Yes.
As shown in FIG. 4B, a silicon oxide (SiO ₂ ) film 51 as an insulating film is uniformly formed on the surface of the susceptor electrode 50, and the thickness of the silicon oxide film 51 is set as follows. It is set to a thickness that can absorb fluctuations in impedance of the wafer that is the processing substrate, for example, about 10,000 mm.
In addition, as a material of the electrode support 46, silicon may be used corresponding to the susceptor electrode 50.

Next, the operation of the batch type plasma processing apparatus 10 according to the above configuration will be described.
When the pod 2 is supplied to the load port 16, the pod loading / unloading port 14 is opened by the front shutter 15.
The pod 2 is automatically transported and delivered by the pod transport device 18 to the designated shelf position of the rotary pod shelf 17.

After being temporarily stored, the pod 2 is transported from the rotary pod shelf 17 to the mounting table 19 a of the pod opener 19 by the pod transport device 18.
The pod 2 placed on the placing table 19a is removed by the cap attaching / detaching mechanism 19b and opened.
When the pod 2 is opened, the wafer transfer device 23a picks up the five wafers 1 in the pod 2 through the wafer loading / unloading port of the pod 2 by the five tweezers 23c at once, and the wafer 1 is boated from the pod 2 into the boat. Then, the five wafers 1 are transferred from the five tweezers 23c onto the five-stage susceptor electrode 50 of the boat 43 at a time.

As described above, when the five wafers 1 are transferred onto the five-stage susceptor electrode 50 at a time, the wafer transfer device 23a returns the tweezers 23c to the pod 2, and the next five wafers 1 are transferred to the susceptor electrode 50. Pick up at once by one sheet of tweezers 23c.
By repeating the above operation, the wafer transfer device 23a sequentially transfers the wafers 1 by 5 on the susceptor electrode 50 group up to the lowest level (in the present embodiment, the 11th level). .
Finally, when the wafer 1 remains, the necessary wafer 1 is transferred to the susceptor electrode 50 by using the independently movable tweezer 23c.

The boat 43 on which the wafer 1 is transferred onto the susceptor electrode 50 at a predetermined stage is lifted by the boat elevator 40 and is loaded into the processing chamber 32 of the processing furnace 30 as shown in FIG. )
When the boat 43 reaches the upper limit, the seal cap 42 closes the furnace port 34 in a sealed state, so that the processing chamber 32 is hermetically closed.
When closed hermetically, the processing chamber 32 is exhausted by the exhaust pipe 36 and heated to a predetermined temperature (for example, about 800 ° C.) by the heater 39.
At this time, since the heater 39 has a hot-wall structure, the temperature of the processing chamber 32 is maintained uniformly throughout, so that the temperature distribution of the group of wafers held in the boat 43 is uniform over the entire length. At the same time, the temperature distribution in the surface of each wafer 1 is uniform and the same.

  After the temperature in the processing chamber 32 reaches a preset value and stabilizes, the processing gas 48 is supplied into the processing chamber 32 from the gas supply pipe 37, and the pressure in the processing chamber 32 becomes a preset value. When it reaches, AC power different in phase by 180 degrees is applied to the susceptor electrode 50 of each stage by the AC power supply 61 and the matching unit 62.

As shown in FIG. 4, a uniform and flat plasma 60 is generated on the entire bottom surface of the susceptor electrode 50 facing the active area of the wafer 1. At this time, since the lower surface of the susceptor electrode 50 is flat, uniform plasma is generated on the entire lower surface of the susceptor electrode 50.
Since this uniform and flat plasma 60 is generated on the active area side of the wafer 1, the main surface of the active area side of the wafer 1 is uniformly subjected to plasma processing over the entire surface.

The processing gas 48 supplied to the gas supply pipe 37 is blown out from the respective outlets 38 to the upper space of the wafer 1 in each stage, and the reaction is activated by the plasma 60 generated on the lower surface of each susceptor electrode 50. Become.
Particles activated by the susceptor electrode 50 at each stage (hereinafter referred to as active particles) come into contact with the main surface on the active area side of the wafer 1 placed on the susceptor electrode 50 at each stage and contact the wafer 1. Apply plasma treatment.
At this time, as described above, the temperature distribution of the wafer 1 is maintained uniformly over the entire length of the boat 43 and within the wafer surface, and the contact distribution of the active particles with the wafer 1 by the uniform and flat plasma 60 is different for each stage. Since the wafers 1 are equal and uniform in the wafer surface of the wafers 1 of the respective stages, the plasma processing state of the wafers 1 by the plasma reaction of the active particles is the wafers 1 of the respective stages and the wafers of the respective stages. It becomes a uniform state within one wafer surface.

  When the processing time set in advance elapses, the supply of the processing gas 48, the heating of the heater 39, the application of AC power, the exhaust of the exhaust pipe 36, etc. are stopped, and then the seal cap 42 is lowered by the boat elevator 40. As a result, the furnace port 34 is opened and the boat 43 is unloaded from the furnace port 34 to the outside of the processing chamber 32 (boat unloading).

The wafer 1 carried out of the processing chamber 32 is accommodated in the pod 2 by a procedure reverse to the operation of the wafer transfer device 23a described above.
By repeating the above operation, a plurality of wafers 1 are batch processed.

By the way, for example, a wafer from which a natural oxide film has been removed by dilute hydrofluoric acid cleaning (hereinafter referred to as a bare wafer) and a wafer on which a metal film has been formed in a previous process (referred to as a patterned wafer) are parallel plate electrodes. The impedance of the wafer 1 is different.
In the plasma processing described above, since the wafer 1 is disposed between the upper and lower susceptor electrodes 50, 50, which are parallel plate electrodes, the generation status of the plasma 60 is affected by the impedance of the wafer 1. The film formation rate and the in-plane film thickness distribution by the plasma 60 with respect to the pattern are different from the film formation rate and the in-plane film thickness distribution by the plasma 60 for the batch of patterned wafers.

In the present embodiment, a silicon oxide film 51 having a thickness of 10,000 mm, which is a thickness not to be confused by the difference between the impedance of the bare wafer and the impedance of the patterned wafer, is formed on the surface of the susceptor electrode 50. Since the generation state of the plasma 60 is uniform between the bare wafer and the patterned wafer, the deposition rate and in-plane film thickness distribution by the plasma 60 for the bare wafer batch, and the formation by the plasma 60 for the batch of patterned wafer are performed. The film rate and in-plane film thickness distribution are almost equal.
In other words, the impedance of the 10000-thick silicon oxide film 51 formed on the surface of the susceptor electrode 50 absorbs the difference between the impedance of the bare wafer and the impedance of the patterned wafer. Evenly between wafers.
Needless to say, the 10,000 Å silicon oxide film 51 formed on the surface of the susceptor electrode 50 is not limited to the difference between the impedance of the bare wafer and the impedance of the wafer with the pattern, but the impedance due to the thin film accompanying the wafer 1 to be subjected to plasma processing. An impedance that can be ignored is generated, and a constant plasma treatment (for example, plasma oxidation, plasma nitridation, BIO) is performed between batches regardless of the presence, type, and thickness of the thin film. it can.

  According to the embodiment, the following effects can be obtained.

(1) By forming a silicon oxide film on the surface of the susceptor electrode, plasma generated by discharge between the susceptor electrodes is generated uniformly regardless of the presence, type, and thickness of the thin film associated with the wafer to be plasma-processed. Therefore, the film formation rate between batches and the in-plane film thickness distribution can be made equal to each other.

(2) By setting the thickness of the silicon oxide film formed on the surface of the susceptor electrode to about 10,000 mm, the impedance is such that the impedance value due to the thin film attached to the wafer to be plasma-treated can be ignored. Since it can be generated, a constant plasma treatment can be performed between batches regardless of the presence, type, and thickness of the thin film.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  For example, the insulating film formed on the surface of the wafer is not limited to a silicon oxide film but may be an insulating film such as a silicon nitride film.

  The feeder that supplies electric power to the susceptor electrode is not limited to be configured to be used also as a holding column of the boat, but may be formed independently of the holding column.

  The batch type plasma processing apparatus according to the present invention can be used for plasma processing such as plasma CVD and dry etching in general.

  Further, the substrate to be processed is not limited to a wafer, but may be a photomask, a printed wiring board, a liquid crystal panel, a compact disk, a magnetic disk, or the like.

1 is a partially omitted perspective view showing a batch type plasma processing apparatus according to an embodiment of the present invention. FIG. It is front sectional drawing which shows a processing furnace. (A) is a circuit diagram which shows the supply circuit of alternating current power, (b) is an expanded sectional view of the b section of (a). It is a partially omitted front sectional view showing a plasma processing step.

Explanation of symbols

1 ... wafer (substrate), 2 ... pod,
DESCRIPTION OF SYMBOLS 10 ... Batch type plasma processing apparatus (substrate processing apparatus), 11 ... Housing, 12 ... Front maintenance port, 13 ... Front maintenance door, 14 ... Pod loading / unloading exit, 15 ... Front shutter, 16 ... Load port,
DESCRIPTION OF SYMBOLS 17 ... Rotary pod shelf, 18 ... Pod conveying apparatus, 18a ... Pod elevator, 18b ... Pod conveying mechanism, 19 ... Pod opener, 19a ... Mounting stand, 19b ... Cap attaching / detaching mechanism,
20 ... Sub housing, 21 ... Wafer loading / unloading port, 22 ... Transfer chamber,
23 ... Wafer transfer mechanism, 23a ... Wafer transfer device, 23b ... Wafer transfer device elevator, 23c ... Tweezer,
26 ... Standby room, 27 ... Clean unit, 28 ... Clean air,
DESCRIPTION OF SYMBOLS 30 ... Processing furnace, 31 ... Process tube, 32 ... Processing chamber, 33 ... Manifold, 34 ... Furnace port, 35 ... Furnace port shutter, 36 ... Exhaust pipe, 37 ... Gas supply pipe, 38 ... Outlet, 39 ... Heater,
40 ... boat elevator, 41 ... arm, 42 ... seal cap,
43 ... Boat (conveying jig), 44, 45 ... End plate, 46 ... Electrode support, 48 ... Processing gas,
50 ... susceptor electrode, 51 ... silicon oxide film (insulating film),
60 ... Plasma, 61 ... AC power supply, 62 ... Matching device.

Claims (1)

A plurality of stages of susceptor electrodes on which a substrate to be processed is placed are arranged at predetermined intervals in the processing chamber, and electric power is supplied to the susceptor electrodes of each stage by a feeder to generate plasma, and the susceptor of each stage is provided. A substrate processing apparatus for plasma processing the target substrate placed on an electrode,
An insulating film having a film thickness that absorbs fluctuations in impedance of the substrate to be processed is formed on each stage of the susceptor electrode.

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