JPH09223685A - Plasma processing apparatus and plasma processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control an exhaust rate in a substrate surface to be processed by providing an exhaust hole at least at any one location on a vertical extention line on a principal surface of the substrate. SOLUTION: A substrate 1 to be processed is placed on a substrate stage 2 serving also as a lower electrode, and a counter electrode 4 is disposed parallely to the substrate 1. A space between the substrate 1 and the counter electrode 4 is a plasma production area, toward which gas introduction holes 5 are disposed in a ring shape to constitute a parallel flat plate type plasma etching apparatus. Thereupon, an exhaust hole 6 is formed in the center of the counter electrode 4, through which exhaust hole 6 there is exhausted exhaust gas containing a reaction product produced from the center of the substrate 1. Herein, a distance between the exhaust hole 6 and the substrate 1 is set to be within the length of a diameter of the substrate 1. Hereby, a highly uniform plasma processing is achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and a plasma processing method used in a semiconductor device manufacturing process and the like, and more particularly, to a uniform plasma processing for a large-diameter substrate to be processed. The present invention relates to a plasma processing apparatus and a plasma processing method suitable for use.

[0002]

2. Description of the Related Art In recent semiconductor devices such as LSIs, the chip area has remarkably increased with the progress of higher integration and higher performance. In order to manufacture a large number of such large-area chips from a single wafer, it is inevitable to increase the diameter of the wafer. In the year 2000, large diameter wafers with a diameter of 12 inches or 30 cm are expected to be used on a mass production basis. Further, a glass substrate having a large screen exceeding 14 inches is also used in a liquid crystal display panel and the like. Various breakthroughs are required in various steps of the semiconductor manufacturing process due to the increase in the diameter of the substrate to be processed.
It is no exception in the field of plasma processing such as plasma etching and plasma CVD.

In the field of plasma etching, conventionally, a large number of substrates to be processed are coaxially arranged in parallel in a cylindrical processing chamber to perform isotropic plasma etching, or on a hex type cathode electrode. A batch type plasma etching apparatus such as a barrel type RIE apparatus that places a plurality of substrates to be processed and performs plasma etching mainly using ions has been widely used in manufacturing sites. However, due to the recent demand for larger diameters of substrates to be processed and fine processing precision, it is almost impossible to meet the required specifications with a batch type plasma etching apparatus, and a single wafer type plasma etching apparatus is being shifted to. Especially for 12 inch wafers,
Considering the footprint occupied by the plasma etching equipment in the clean room, that is, the footprint, batch type equipment such as barrel type is too large to be practical, and there is no choice but to shift to single wafer type. Is a common recognition in the semiconductor device manufacturing industry.

Even in the single-wafer type plasma etching apparatus corresponding to the large diameter, it is an important subject to make the processing uniform over the entire surface of the substrate to be processed. In the conventional medium-diameter substrate of less than 8 inches, the uniformization of the etching process can be achieved to some extent by the uniformization of the plasma density and the etching gas supply of the plasma etching apparatus. However, in the case of a large-diameter substrate, in addition to the conventional homogenization method, reaction products with a large vapor pressure generated by the reaction between the etching gas and the material to be etched, that is, exhaust gas, can be uniformly and promptly from the substrate to be etched. Removal is becoming essential. This problem will be described with reference to FIG.

FIG. 10 shows a substrate to be processed in a processing chamber of a parallel plate type RIE apparatus, from the peripheral portion of the substrate to be processed.
Alternatively, it shows various characteristics when plasma etching is performed by a conventional method of exhausting reaction products from the lower portion of the substrate to be processed via the peripheral portion. As the substrate to be processed, a semiconductor substrate having a diameter of 12 inches and a resist mask formed on the interlayer insulating film is adopted, and a case where contact hole processing is performed on the interlayer insulating film is taken as an example.

In each of the figures, the horizontal axis indicates the radial distance from the center of the substrate to be processed, FIG. 10 (a) shows the exhaust speed of reaction products directly above the substrate to be processed, and FIG. 10 (b) shows The vertical axis represents the etching rate and the taper angle of the side surface of the contact hole. As is apparent from the figure, the exhaust speed is small in the central part of the substrate to be processed and large in the peripheral part. Due to this exhaust velocity distribution, the etching rate is small in the central part of the substrate to be processed and large in the peripheral part. Further, the taper angle, that is, the angle formed by the side surface of the contact hole with the semiconductor substrate (the angle viewed from the inside of the contact hole) is substantially vertical at the peripheral portion, whereas the central portion has a forward tapered shape.

As described above, the contact hole etching is not the only example in which the etching characteristics are affected by the exhaust rate of the reaction products. For example, in refractory metal polycide wiring processing with Cl ₂ gas, _if the exhaust rate of the reaction product WCl _x during WSi _x etching is non-uniform within the surface of the substrate to be processed, the shape of the WSi _x portion is forward tapered. Or side etching occurs. Further, in the case of processing an Al-based metal wiring with a Cl-based gas, the formed Al-based metal wiring is still due to the non-uniform exhaust rate of the reaction product AlCl _x and the sputtering product of the resist mask that becomes the sidewall protection film. It may be forward tapered or reverse tapered.

[0008]

The present invention is proposed based on such a technical background. That is, an object of the present invention is to provide a plasma processing apparatus and a plasma capable of achieving uniform plasma processing by controlling the exhaust speed in the surface of the substrate to be processed when performing a predetermined plasma process on a large-diameter substrate to be processed. It is to provide a processing method.

[0009]

The plasma processing apparatus of the present invention is proposed in order to achieve the above-mentioned object, and is a plasma for performing a predetermined plasma processing on a substrate to be processed arranged in a processing chamber. The processing apparatus is characterized in that an exhaust hole is provided on a vertical extension line of the main surface of the substrate to be processed, that is, at least one position immediately above the substrate to be processed.

Further, the plasma processing method of the present invention is a plasma processing method for subjecting a substrate to be processed, which is disposed in a processing chamber, to a predetermined plasma processing, which is on a vertical extension line of the main surface of the substrate to be processed. It is characterized in that the plasma processing is performed while exhausting from at least one place directly above the substrate to be processed.

In the plasma processing apparatus and the plasma processing method of the present invention, the distance between at least one exhaust hole on the vertical extension line of the main surface of the substrate to be processed and the substrate to be processed is the diameter of the substrate to be processed. It is desirable to set within the length, more preferably within the radius of the substrate to be processed, and exhaust from this distance.

Further, in addition to at least one exhaust hole on the vertical extension line of the main surface of the substrate to be processed, an exhaust opening is further provided in the peripheral portion of the substrate to be processed so that the peripheral portion of the substrate can also be exhausted. desirable.

Further, an exhaust amount for individually controlling an exhaust amount from at least one exhaust hole on a vertical extension line of the main surface of the substrate to be processed and an exhaust amount from an exhaust opening at a peripheral portion of the substrate to be processed. The plasma processing is provided with a control means, while individually controlling the exhaust amount from at least one position on the vertical extension line of the main surface of the substrate to be processed and the exhaust amount from the exhaust opening at the peripheral portion of the substrate to be processed. It is desirable to apply. In order to control the exhaust amount of the plurality of exhaust means, a computer, etc., in which the degree of opening of the conductance valve interposed between each exhaust means and the vacuum pump and the optimal exhaust amount data for each plasma processing are input in advance, are used. A method of controlling by etc. is adopted.

Next, the operation will be described. The technical idea of the present invention is that, in order to perform uniform plasma processing on a substrate having a large diameter of, for example, 8 inches or more, in addition to making the plasma density and the supply of the processing gas uniform, the reaction generation from the substrate to be processed is performed. The point is that the removal of exhaust gas containing substances is also controlled arbitrarily.
In particular, for a large-diameter substrate to be processed, paying attention to the fact that the exhaust efficiency at the central part of the substrate to be processed decreases and the exhaust gas tends to stagnant, and an exhaust hole is provided directly above the substrate to be exhausted through this exhaust hole. By doing so, a uniform plasma treatment is achieved.
The distance between the exhaust hole and the substrate to be processed is the diameter of the substrate to be processed,
The exhaust efficiency from the central portion of the substrate to be processed becomes favorable by setting the radius within the radius.

Further, in addition to the exhaust hole directly above the substrate to be processed, an exhaust opening is also provided in the peripheral portion of the substrate to be processed, and exhaust gas is removed by a plurality of systems of exhaust means to highly control the profile of the exhaust gas flow. be able to. Further, by individually controlling the exhaust amount from the exhaust hole directly above the substrate to be processed and the exhaust amount from the exhaust opening at the peripheral portion of the substrate to be processed,
The profile of the exhaust gas flow can be controlled more strictly, and uniform plasma processing can be performed.

[0016]

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

Embodiment 1 This embodiment schematically shows the principle of the present invention by taking a parallel plate type plasma etching apparatus as an example.
This will be described with reference to FIG. In FIG. 1A, the substrate 1 having a diameter of 12 inches, for example, is placed on the lower electrode / substrate stage 2, and the counter electrode 4 is the substrate 1 to be processed.
It is arranged parallel to and opposite to. The space between the substrate 1 to be processed and the counter electrode 4 is a plasma generation region, and gas introduction holes 5 for the processing gas are arranged in a ring shape toward this space. The above is the configuration of a normal parallel plate type plasma etching apparatus. As a characteristic configuration of the present embodiment, an exhaust hole 6 is formed in the central portion of the counter electrode 4, and the exhaust hole 6 is provided through this exhaust hole 6. Exhaust gas containing reaction products generated from the central portion of the substrate 1 to be processed can be removed.

FIG. 1B shows another example of the parallel plate type plasma etching apparatus. This device constitutes a so-called gas shower head in which the gas introduction hole 5 is incorporated in the counter electrode 4 in order to uniformly supply the processing gas. Counter electrode 4
The exhaust hole 6 is formed in the central portion of the substrate, and the exhaust gas containing the reaction product generated from the central portion of the substrate 1 having a diameter of, for example, 12 inches can be removed via the exhaust hole 6. It is similar to the device shown in FIG. 1 (a) and 1 (b), the details of the apparatus such as the processing chamber and the high frequency power source are omitted for simplification of description.

A parallel plate type plasma etching apparatus shown in FIGS. 1A and 1B is used, in which a resist mask for opening a contact hole is formed on an interlayer insulating film of a semiconductor substrate having a diameter of 12 inches as a substrate to be processed. Adopted and subjected to plasma etching. The results are shown in FIGS. 2 (a) and 2 (b). In FIG. 2A, the horizontal axis indicates the radial distance from the center of the substrate to be processed, FIG. 2A shows the exhaust speed of reaction products directly above the substrate, and FIG. 2B shows the etching rate. The vertical axis indicates the taper angle of the side surface of the contact hole. As is clear from the figure, the pumping speed is almost equal in the central portion of the substrate to be processed and the peripheral portion. Due to this uniform exhaust velocity distribution, the etching rate and the taper angle show almost the same values in the central part and the peripheral part of the substrate to be processed, and it can be seen that uniform plasma etching is performed.

Embodiment 2 This embodiment is an example of actual contact hole etching performed by a parallel plate type plasma etching apparatus, which will be described with reference to FIGS. 3 and 7. FIG. 3 is a schematic sectional view of a parallel plate type plasma etching apparatus to which the present invention is applied. The basic configuration of this plasma etching apparatus is the same as that described with reference to FIG. 1B, and for example, a substrate stage 2 which also serves as a lower electrode on which a 12-inch target substrate 1 is mounted and which is connected to a high-frequency power source 3 and A large number of gas introduction holes 5 are formed and include the counter electrode 4 which constitutes a gas shower head. The gas introduction hole 5 can be switched between a mode in which the etching gas is uniformly introduced from the entire surface of the counter electrode 4 and a mode in which the etching gas is introduced in a ring shape only from the peripheral portion of the counter electrode 4.
A characteristic part of the plasma etching apparatus is an exhaust hole 6 that opens at the center of the counter electrode 4. In this apparatus, the distance between the exhaust hole 6 and the substrate 1 to be processed can be varied, for example, from several mm to several tens of mm. In addition to this, the exhaust system has an exhaust opening 7 from the peripheral portion of the substrate to be processed. In FIG. 3, details of the device such as the conductance valve of each exhaust system and control means such as a computer for controlling the opening degree, holding means for the substrate to be processed and temperature control means, and vacuum pump are omitted. According to the plasma etching apparatus of the present invention, it is possible to perform uniform plasma etching on the substrate to be processed 1 by exhausting two systems from directly above the substrate to be processed 1 and from the peripheral portion.

Next, an example in which contact holes are etched by the present plasma etching apparatus will be described with reference to FIG. The substrate to be processed used in this example is shown in FIG.
As shown in FIG. 1, as an example, an interlayer insulating film 101 and a resist mask 102 for opening a connection hole are formed on a semiconductor substrate 100 such as silicon having a diameter of 12 inches.
The interlayer insulating film 101 is, for example, S formed by atmospheric pressure CVD method.
The resist mask 102 is made of iO ₂ and has a thickness of 1100 nm. The resist mask 102 is made of a chemically amplified resist, and an opening having a diameter of 0.3 μm is formed on the entire surface of the substrate to be processed by excimer laser lithography.

This substrate to be processed is placed on the lower electrode / substrate stage 2 of the parallel plate type plasma etching apparatus shown in FIG. 3, and as an example, the interlayer insulating film 101 exposed from the resist mask 102 under the following plasma etching conditions.
Was patterned. CF ₄ flow rate 20 sccm CHF ₃ flow rate 20 sccm Ar flow rate 300 sccm Gas pressure 10 Pa High frequency power supply 1500 W (13.56 MHz) Substrate temperature 20 ° C. Electrode distance 5 mm Over etching 30% In this plasma etching process, etching mixture is used. The gas was supplied from the peripheral portion of the counter electrode 4. The exhaust gas generated by the etching reaction is also exhausted from directly above the central portion of the substrate 1 to be processed, so that the active species are sufficiently spread to the central portion of the substrate 1 to be processed, and the exhaust gas inside the connection hole having a high aspect ratio is also smooth. It is carried out. In this embodiment, the exhaust hole 6 immediately above the central portion of the substrate 1 to be processed and the exhaust opening 7 at the peripheral portion.
The exhaust amount from the engine was set to 1: 3, for example.

As a result, etching with no etching rate or pattern conversion difference progressed over the entire surface of the large-diameter substrate 1 to be processed, and the connection hole 103 having vertical side walls was formed as shown in FIG. 7B.

Example 3 This example is an example in which the same parallel plate type plasma etching apparatus as in Example 2 was adopted as a plasma etching apparatus and contact hole etching was performed. The substrate to be processed and the basic plasma etching conditions are also the same as those in the second embodiment, and the overlapping description will be omitted. However, the difference of this embodiment from the second embodiment is that the etching mixed gas is applied from the entire surface of the counter electrode 4. The point is that the gas is supplied in a uniform gas shower shape toward the processing substrate 1.

In this etching step, the active species involved in the etching are evenly supplied to the surface of the substrate 1 to be processed, and the exhaust gas generated by the etching reaction is exhausted from just above the central portion of the substrate 1 to be processed. The exhaust of the inside of the high aspect ratio connection hole is also done smoothly. In this embodiment, the exhaust amount from the exhaust hole 6 immediately above the central portion of the substrate 1 to be processed and the exhaust opening 7 at the peripheral portion is set to 1: 4, for example.

As a result, etching with no etching rate or pattern conversion difference progressed over the entire surface of the large-diameter substrate 1 to be processed, and the connection hole 103 having vertical sidewalls was formed as shown in FIG. 7B.

Embodiment 4 This embodiment is an example in which a gate electrode is processed by an MCR type plasma etching apparatus, which will be described with reference to FIGS. 4 and 8.

FIG. 4 shows the MCR (Mag) used in this embodiment.
Netly Confined Reacto
r) A schematic cross-sectional view of a plasma etching apparatus. In the same apparatus, reference numeral 8 is an annular side wall electrode to which a side wall electrode power supply 9 is applied, and reference numeral 4 is a counter electrode having a gas shower head type gas introduction hole 5, which is connected to the ground potential. The substrate 1 to be processed is placed on a lower electrode / substrate stage 2 to which a high frequency power source 3 is connected. Outside the sidewall electrode 8 and the counter electrode 4, a multi-pole magnet (not shown) is arranged. The basic configuration of this plasma etching apparatus is, for example, 1992 18th. Teagal
Plasma Seminar Proceedin
gs, p. 44. According to the present plasma etching apparatus, discharge is started between the side wall electrode 8 and the counter electrode 4, and the generated plasma is confined in the processing chamber by the multi-pole magnet, and the magnetron RIE is performed.
It is possible to obtain a higher density plasma than the device. Further, the ion energy incident on the substrate 1 to be processed can be controlled by the high frequency power source 3. MCR adopted in this embodiment
A feature of the plasma etching apparatus is the exhaust hole 6 provided in the central portion of the counter electrode 4. In addition to this, the exhaust system has an exhaust opening 7 in the peripheral portion of the counter electrode 4, which takes charge of exhaust from the peripheral portion of the substrate 1 to be processed. In FIG. 4, details of the device such as the conductance valve of each exhaust system, the control means for controlling the opening degree, the holding means for the substrate to be processed, the temperature control means, and the vacuum pump are omitted. According to the plasma etching apparatus of the present invention, it is possible to perform uniform plasma etching on the substrate to be processed 1 by exhausting two systems from directly above the substrate to be processed 1 and from the peripheral portion.

Next, an example in which the gate electrode is etched by the present plasma etching apparatus will be described with reference to FIG. As shown in FIG. 8A, the substrate to be processed employed in this embodiment is, for example, a gate insulating film 104, a polycrystalline silicon layer 105, WSi _x formed on a semiconductor substrate 100 such as silicon having a diameter of 12 inches. The refractory metal silicide layer 106 and the resist mask 102 for processing the gate electrode are sequentially formed. Of these, the gate insulating film 104 is formed by thermal oxidation of SiO ₂ to a thickness of 6 nm, and the polycrystalline silicon layer 105 and the refractory metal silicide layer 106 are each formed by a CVD method to a thickness of 80 nm. The resist mask 102 is made of a chemically amplified resist, and is formed on the entire surface of the processed substrate by excimer laser lithography in the shape of a gate electrode having a width of 0.3 μm.

This substrate to be processed is placed on the lower electrode / substrate stage 2 of the MCR type plasma etching apparatus shown in FIG. 4, and as an example, the high melting point exposed from the resist mask 102 under the following two stages of plasma etching conditions. Metal silicide layer 106 and polycrystalline silicon layer 10
5 was patterned. Main etching process Cl ₂ flow rate 20 sccm Ar flow rate 50 sccm Gas pressure 1.0 Pa Sidewall electrode power supply power 1000 W (13.56 MHz) High frequency power supply power 80 W (450 kHz) Substrate temperature 20 ° C. Overetching process Cl ₂ flow rate 20 sccm HBr Flow rate 30 sccm Gas pressure 1.0 Pa Side wall electrode power supply power 1000 W (13.56 MHz) High frequency power supply power 10 W (450 kHz) Substrate temperature 20 ° C. Overetching 40% In this plasma etching process, the etching mixed gas is a gas showerhead. It was uniformly supplied from the entire surface of the counter electrode 4 having the structure. Exhaust gas generated by the etching reaction is exhausted from directly above the central portion and the peripheral portion of the substrate 1 to be processed, so that the reaction products that are easily deposited on the sidewall of the pattern to be processed are smoothly exhausted over the entire surface of the substrate 1. . As a result, the difference in etching rate and the difference in shape are negligible over the entire surface of the substrate to be processed 1, a refractory metal polycide electrode having a vertical shape is formed, a selection ratio to the gate insulating film can be secured, and a residue or the like is generated. There wasn't.

According to the present embodiment, in the MCR type plasma etching apparatus, by adopting the exhaust from the exhaust hole directly above the substrate to be processed, it is possible to uniformly process the gate electrode even on the substrate to be processed having a large diameter. Is possible.

Embodiment 5 This embodiment is an example in which the present invention is applied to an ICP type plasma etching apparatus to perform Al-based metal wiring processing, which will be described with reference to FIGS. 5 and 9.

FIG. 5 shows the ICP (Ind used in this embodiment.
It is a schematic sectional drawing which shows the structural example of an active coupled plasma) etching device. In the apparatus, reference numeral 11 is an ICP coil to which ICP power supply power is applied from an ICP power supply 12, and a substrate bias is applied from a high frequency power supply 3 to a lower electrode / substrate stage 2 on which a substrate 1 to be processed is placed and incident. Ion energy can be controlled independently. Reference numeral 4 denotes a counter electrode having a ground potential whose inner surface is covered with a silicon-based material layer, and the counter electrode 4 can be heated according to the material layer to be etched. The etching gas is introduced through gas introduction holes 5 arranged in a ring shape around the periphery of the substrate 1 to be etched. According to the basic configuration of this plasma etching apparatus, it is possible to perform etching with high-density plasma of 10 ¹² / cm ³ by the discharge excited by the large multi-turn ICP coil 11. The characteristic part of this apparatus is an exhaust hole 6 opened in the counter electrode 4 directly above the substrate 1 to be processed. In addition to this, the exhaust system has an exhaust opening 7 around the substrate 1 to be processed. In FIG. 5, details of the device such as the conductance valve of each exhaust system and the control means for controlling the opening degree, the holding means for the substrate to be processed, the temperature control means, and the vacuum pump are omitted. According to the present plasma etching apparatus, uniform high-density plasma etching can be performed on the substrate 1 to be processed by exhausting two systems from directly above the substrate 1 and from the peripheral portion.

Next, using the present plasma etching apparatus,
An example in which the 1-based metal wiring is etched will be described with reference to FIG. As shown in FIG. 9A, the substrate to be processed employed in this embodiment is, for example, a barrier metal layer 107, Al and Al on an interlayer insulating film 101 on a semiconductor substrate (not shown) such as silicon having a diameter of 12 inches. System metal layer 108, antireflection layer 10
9 and a resist mask 102 for Al-based metal wiring processing
Are sequentially formed. Of these, the barrier metal layer 107 is Ti / TiN 40/60 nm, the Al-based metal layer 108 is Al-2% Cu 400 nm, and the antireflection layer 1 is formed.
Reference numeral 09 denotes TiN formed to have a thickness of 30 nm by sputtering or reactive sputtering. The resist mask 102 is made of a chemically amplified resist and has a thickness of 0.3 μm formed by excimer laser lithography.
It is patterned to a wiring width of m.

This substrate to be processed is placed on the lower electrode / substrate stage 2 of the ICP etching apparatus shown in FIG. 5, and as an example, the antireflection layer 109 exposed from the resist mask 102 under the following two-step plasma etching conditions, A
The l-based metal layer 108 and the barrier metal layer 107 were patterned. Main etching process Cl ₂ flow rate 20 sccm BCl ₃ flow rate 50 sccm Gas pressure 1.0 Pa ICP power supply power 1500 W (2.0 MHz) High frequency power supply power 250 W (1.8 MHz) Substrate temperature 30 ° C. Overetching process Cl ₂ flow rate 30 sccm BCl ₃ flow rate 20 sccm Ar flow rate 50 sccm Gas pressure 1.0 Pa ICP power supply power 1000 W (2.0 MHz) High frequency power supply power 100 W (1.8 MHz) Substrate temperature 30 ° C. Overetching 50% In this plasma etching process The etching mixed gas is introduced through the gas introduction hole 5 arranged in a ring shape around the substrate 1 to be processed, but the exhaust gas generated by the etching reaction is also exhausted from directly above the central portion of the substrate 1 to be processed. , The center of the substrate 1 to be processed Active species of ching spread. In addition, the decomposition products of the resist mask 102 and the etching reaction products were uniformly exhausted right above the substrate 1 to be processed and from the peripheral portion. As a result, the difference in etching rate and the difference in shape were negligible over the entire surface of the substrate 1 to be processed, Al-based metal wiring having a vertical shape was formed as shown in FIG. 9B, and no residue was generated.

According to this embodiment, in the ICP etching apparatus, the exhaust from the exhaust hole directly above the substrate to be processed is adopted, so that the uniform A
It is possible to perform the l-based metal wiring processing.

Embodiment 6 This embodiment is an example in which the present invention is applied to a SWP type plasma etching apparatus to perform contact hole etching. This will be described with reference to FIGS. 6 and 7.

FIG. 6 shows the SWP (Sur used in this embodiment.
It is a schematic sectional drawing which shows the structural example of a face wave plasma) etching device. The basic components of the device are the Al plate 13 and the fluororesin sheet 17.
Laminated cavity consisting of, microwave waveguide 16, gas introduction hole 5 provided in the side wall of the processing chamber, substrate 1 to be processed
Are the lower electrode / substrate stage 2 and the high-frequency power source 3 on which is mounted. According to the present plasma etching apparatus, the microwave generated by the magnetron (not shown) propagates in the microwave waveguide 16 and the surface wave plasma is generated in the laminated cavity composed of the Al plate 13 and the fluorine resin sheet 17. To do. The surface wave plasma reaches the substrate 1 to be processed through the alumina plate 14 which is a dielectric. Further, the high frequency power source connected to the lower electrode / substrate stage 2 can control the ion energy incident on the substrate 1 to be processed independently of the plasma density. The details of this device are, for example, 1994 Dry.
Process Symposium Proceedings, VI-
10, p235. The feature of the SWP etching apparatus adopted in this embodiment is the exhaust hole 6 provided directly above the substrate 1 to be processed, and part of the exhaust gas is exhausted from the space defined by the exhaust plate 15 to the outside of the processing chamber. . In addition to this, the exhaust system has an exhaust opening 7 in the peripheral portion of the substrate 1 to be processed. In FIG. 6, details of the device such as the conductance valve of each exhaust system and the control means for controlling the opening, the holding means for the substrate to be processed, the temperature control means, and the vacuum pump are omitted. According to the plasma etching apparatus of the present invention, the two systems of exhaust air are provided directly above the substrate to be processed 1 and from the peripheral portion,
It is possible to perform uniform plasma etching on the substrate 1 to be processed.

Next, an example in which contact hole etching is performed by this plasma etching apparatus will be described with reference to FIG. The substrate to be processed shown in FIG. 7A used in this embodiment is the same as that used in the second embodiment, and the duplicate description will be omitted. The substrate to be processed was placed on the lower electrode / substrate stage 2 of the SWP etching apparatus shown in FIG. 6, and as an example, the interlayer insulating film 101 exposed from the resist mask 102 was patterned under the following two-step plasma etching conditions. Main etching process CF ₄ flow rate 50 sccm CH ₂ F ₂ flow rate 20 sccm Gas pressure 1.0 Pa Microwave power supply power 500 W (2.45 GHz) High frequency power supply power 150 W (400 kHz) Substrate temperature 20 ° C. Overetching process CF ₄ flow rate 50 sccm CH ₂ F ₂ flow rate 40 sccm Gas pressure 1.0 Pa Microwave power supply power 500 W (2.45 GHz) High frequency power supply power 100 W (400 kHz) Substrate temperature 20 ° C. Overetching 30% Etching in this plasma etching process The mixed gas is supplied from the peripheral portion of the substrate to be processed, but since the exhaust gas is also removed from the exhaust hole 6 directly above the substrate to be processed 1, the etching active species are evenly distributed in the central portion of the substrate to be processed 1. Supplied. As a result, it was possible to form the connection hole 103 having a uniform shape as shown in FIG. 7B over the entire surface of the substrate having a large diameter of 12 inches.

Although the present invention has been described above with reference to six examples, these are merely examples and the present invention is not limited to these examples. That is, the technical idea of the present invention can be enjoyed if the plasma processing uses a plasma processing apparatus in which an exhaust hole is provided at any one position on the vertical extension line of the substrate to be processed, and the position and the number of the exhaust holes can be enjoyed. Etc. may be set arbitrarily. In addition to plasma etching, the present invention can be applied to any surface treatment using plasma, such as plasma CVD.

[0041]

As is apparent from the above description, according to the plasma processing apparatus and the plasma processing method of the present invention,
It is possible to perform highly uniform plasma processing not only on a large-diameter substrate to be processed, but also on a normal substrate to be processed having a size of 8 inches or less, a rectangular substrate to be processed for a liquid crystal panel, and the like.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the principle of the present invention by taking a parallel plate type plasma processing apparatus as an example.

FIG. 2 is a graph showing the effect of plasma etching according to the present invention.

FIG. 3 is a schematic sectional view of a parallel plate type plasma etching apparatus to which the present invention is applied.

FIG. 4 is a schematic sectional view of an MCR plasma etching apparatus to which the present invention is applied.

FIG. 5 is a schematic sectional view of an ICP etching apparatus to which the present invention is applied.

FIG. 6 is a schematic sectional view of a SWP etching apparatus to which the present invention is applied.

FIG. 7 is a schematic sectional view showing contact hole etching to which the present invention is applied in the order of steps thereof.

FIG. 8 is a schematic cross-sectional view showing the step of etching a gate electrode to which the present invention is applied.

FIG. 9 is a schematic cross-sectional view showing Al-based metal wiring etching to which the present invention is applied in the order of steps thereof.

FIG. 10 is a graph showing a problem of conventional plasma etching.

[Explanation of symbols]

 1 substrate to be processed 2 lower electrode / substrate stage 3 high frequency power supply 4 counter electrode 5 gas introduction hole 6 exhaust hole 7 exhaust opening 8 sidewall electrode 9 sidewall electrode power supply 10 heater 11 ICP coil 12 ICP power supply 13 Al plate 14 alumina plate 15 exhaust plate 16 microwave waveguide 17 fluororesin sheet 100 semiconductor substrate 101 interlayer insulating film 102 resist mask 103 connection hole 104 gate insulating film 105 polycrystalline silicon layer 106 refractory metal silicide layer 107 barrier metal layer 108 Al-based metal layer 109 antireflection layer

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display area H01L 21/205 H01L 21/205 H05H 1/46 H05H 1/46 M

Claims (8)

[Claims] 1. A plasma processing apparatus for performing a predetermined plasma processing on a substrate to be processed arranged in a processing chamber, wherein the plasma is exhausted to at least one position on a vertical extension line of the main surface of the substrate to be processed. A plasma processing apparatus comprising a hole. 2. The distance between at least one exhaust hole on the vertical extension line of the main surface of the substrate to be processed and the substrate to be processed is within the length of the diameter of the substrate to be processed. The plasma processing apparatus according to claim 1. 3. The exhaust opening is provided at at least one exhaust hole on a vertical extension line of the main surface of the substrate to be processed, and further, an exhaust opening is provided at a peripheral portion of the substrate to be processed. Plasma processing equipment. 4. An exhaust gas for individually controlling an exhaust gas amount from at least one exhaust hole on a vertical extension line of a main surface of a substrate to be processed and an exhaust gas amount from an exhaust opening at a peripheral portion of the substrate to be processed. 4. The plasma processing apparatus according to claim 3, further comprising a quantity control means. 5. A plasma processing method for subjecting a substrate to be processed, which is disposed in a processing chamber, to a predetermined plasma process, comprising exhausting from at least one position on a vertical extension line of the main surface of the substrate to be processed. A plasma processing method, characterized in that the plasma processing is performed while performing the plasma processing. 6. The exhaust from any at least one position on a vertical extension line of the main surface of the substrate to be processed is an exhaust from a position where a distance from the substrate to be processed is within a length of a diameter of the substrate to be processed. The plasma processing method according to claim 5, wherein 7. The plasma processing is performed while exhausting gas from at least one position on a vertical extension line of the main surface of the substrate to be processed, and further exhausting gas from the peripheral portion of the substrate to be processed. 5. The plasma processing method according to 5. 8. The plasma processing is performed while individually controlling an exhaust amount from at least one position on a vertical extension line of the main surface of the substrate to be processed and an exhaust amount from an exhaust opening at a peripheral portion of the substrate to be processed. The plasma processing apparatus according to claim 7, which is performed.