JP2002118104A - Plasma treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma treating device that can improve in-plane uniformity in the film thickness of a wafer to be treated even if the aperture of the wafer becomes large. SOLUTION: In this plasma treating device, plasma treatment is made to the wafer W to be treated. The wafer W is arranged in an airtight treatment container 4, and is placed on a susceptor 6. The plasma treating device has an antenna member 22 provided outside the treatment container, a high-frequency power supply 32 connected to the antenna member, a plurality of treatment gas supply paths 56A and 56B, a gas supply section for supplying a treatment gas into the treatment container from a treatment gas jet hole communicating with the treatment gas supply path, and exhaust vents 58A and 58B for carrying out exhaust in the treatment container. The gas supply section is arranged upward as compared with the surface of the body to be treated. The treatment gas jet hole communicating with the treatment gas supply path is positioned in the circumference direction of the treatment container, is nearly equally arranged, and discharges the treatment gas toward the center section in the treatment container, thus making uniform the plasma of treatment space and the concentration of reaction species, and hence greatly improving the in-plane uniformity in thickness in deposition.

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 more particularly to a plasma processing apparatus for forming a film.

[0002]

2. Description of the Related Art Generally, in a semiconductor manufacturing process, a semiconductor wafer as an object to be processed is subjected to various processes, for example, a film forming process. Plasma CVD (Chemi)
cal Vapor Deposition) is known.

[0003] In a plasma processing apparatus for performing this processing, for example, two flat electrodes are placed in a processing container in parallel,
During this time, for example, 1
A plasma is generated by applying a high frequency voltage of 3.56 MHz, and a process such as etching is performed on the wafer surface.

[0004] As described above, the plasma generated between the parallel plate electrodes causes an electric field to be an alternating magnetic field directed from one electrode to the other electrode, so that electrons are attracted along this electric field and collide with gas molecules. As a result, a gas which is not easily thermally excited is activated, and a desired film is formed.

Although it is very important to form a film with a uniform thickness on a wafer surface in order to improve the yield of semiconductor products, the thickness of the film greatly affects the method of supplying a source gas. That is the fact. As a method for supplying the source gas, a method in which a supply nozzle is inserted from the side wall of the processing container and the source gas is supplied toward the surface of the wafer, or the upper electrode has a flat shower head structure, From this, a method of supplying a raw material gas toward the wafer surface side is known.

[0006]

However, as described above, simply supplying the source gas from the side wall of the processing chamber makes it difficult for the reactive species contributing to film formation to sufficiently reach the vicinity of the center of the wafer. It was difficult to form a film with a uniform thickness. In addition, in the case of a mere flat plate showerhead structure, the flow of the supply gas may be disturbed, and in this case, it is relatively difficult to ensure uniformity of the film thickness in the wafer surface.

The inventor of the present invention has also disclosed a prior application (Japanese Patent Application No. Hei.
No. 317375) proposed a so-called inductively-coupled plasma forming method in which an antenna member is provided in the upper portion of the processing vessel or outside the ceiling and plasma is induced by electromagnetic waves from the antenna member.

According to this method, plasma can be generated even under a low pressure of 1 × 10 ⁻³ Torr or less and the uniformity of the plasma can be improved, so that the processing characteristics of plasma etching and plasma film formation can be improved. However, when the above-described showerhead structure is employed in this inductively-coupled plasma processing apparatus, a part of the electromagnetic wave from the antenna member is absorbed by the showerhead structure made of a dielectric material, and the plasma generation efficiency is reduced. Will be invited. Therefore, in the case of an inductively coupled plasma processing apparatus, in order to prevent a reduction in the plasma generation efficiency, the raw material gas and the like must be introduced from the side wall of the processing container. There has been a problem that the inner uniformity cannot be sufficiently ensured. In particular, when the diameter of a semiconductor wafer is increased and a large wafer such as, for example, an 8-inch wafer is formed, it becomes a major problem to make the gas concentration uniform between the central portion and the peripheral portion of the wafer.

The present invention focuses on the above problems,
It was created to solve this effectively. An object of the present invention is to provide a plasma processing apparatus that can improve the in-plane uniformity of the film thickness even if the diameter of the object to be processed increases.

[0010]

As a result of intensive studies, the present inventor has found that when a source gas is introduced from the side wall of the processing vessel, the distance between the tip of the nozzle and the wafer edge is large in the in-plane uniformity of the film formation. The present invention has been made based on the finding that it is better to provide a gas outlet having a plurality of stages in order to supply a gas having a uniform concentration to the center of the wafer as the diameter of the wafer is increased. Things.

According to a first aspect of the present invention, there is provided a plasma processing apparatus for performing a plasma process on an object placed on a susceptor and disposed in an airtight processing container. An antenna member provided outside the processing container, and a high-frequency power supply connected to the antenna member,
A gas supply unit having a plurality of processing gas supply passages, for supplying a processing gas into the processing container from a processing gas ejection hole communicating with the processing gas supply passage, and an exhaust port for exhausting the inside of the processing container Wherein the gas supply unit is disposed above the surface of the object to be processed, and the position of the processing gas ejection hole communicating with the processing gas supply passage is located in the circumferential direction of the processing container, and is substantially uniform. And a processing gas is discharged toward a central portion in the processing container.

According to a second aspect of the present invention, there is provided a plasma processing apparatus for performing plasma processing on an object to be processed mounted on a susceptor and disposed in an airtight processing container, wherein the antenna is provided outside the processing container. A member, a high-frequency power supply connected to the antenna member, a mounting table that holds the object to be processed and is heatable in the processing container, and a plurality of processing gas supply passages, and is in communication with the processing gas supply passage. A gas supply unit for supplying a processing gas from the processing gas ejection hole into the processing container, and an exhaust port for exhausting the processing container,
The gas supply unit is disposed above the surface of the object to be processed, and the position of the processing gas ejection hole that communicates with the processing gas supply passage is located in the circumferential direction of the processing container, and is disposed substantially equally. The plasma processing apparatus discharges a processing gas toward a central portion in the processing container.

In this case, for example, the gas supply unit is a nozzle. Further, for example, the gas supply unit is a gas supply head. Further, for example, as defined in claim 5, the gas supply portion has a dome-shaped or tapered shape on the gas ejection hole surface side.

[0014]

Since the present invention is constructed as described above, the processing gas supplied from the processing gas ejection hole is excited by the electromagnetic waves from the antenna member connected to the high frequency power supply, and becomes a reactive species for film formation. . Here, the processing gas ejection holes are provided in a plurality of stages in the processing container, and the ejection holes located on the upper stage side are:
It is located on the center side of the processing container. Therefore, the source gas such as silane from the processing gas ejection hole located on the lower side mainly contributes to the film formation on the peripheral portion of the object to be processed, and the source gas from the processing gas ejection hole located on the upper side mainly It contributes to film formation near the center of the object. Therefore, in-plane uniformity of a film formed as a whole can be improved. in this case,
In order to form a processing gas supply passage, a plurality of supply nozzles extending radially from the side wall of the processing container may be provided.

[0015] Further, above the processing gas ejection hole,
By providing an additive gas ejection hole for supplying an additive gas such as Ar gas or oxygen, the additive gas and the processing gas can be more uniformly mixed, and the in-plane uniformity of the film can be further improved. Further, a second or third process gas supply method is used.
As in the invention, a gas supply head having a dome-shaped or tapered gas ejection surface may be provided in the processing container, and the processing gas ejection holes may be provided in a plurality of stages on the gas ejection surface.

According to this, similarly to the first invention, the processing gas outlet located at the upper side is located closer to the center of the processing container than the processing gas outlet located at the lower side. Therefore, the same function and effect as those of the first invention can be exhibited.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the plasma processing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. 1 is a schematic perspective view showing a plasma processing apparatus according to the present invention, FIG. 2 is a cross-sectional view of the processing apparatus shown in FIG. 1, FIG. 3 is a plan view of the processing apparatus shown in FIG. FIG. 5 shows a positional relationship between a nozzle and a wafer in order to evaluate film formation.
Is a graph showing the in-plane uniformity of the film thickness with respect to the distance between the nozzle tip and the wafer in the height direction, FIG. 6 is a graph showing the in-plane uniformity of the film thickness with respect to the length of the nozzle, and FIG. 7 is a graph shown in FIG. FIG. 9 is an explanatory diagram for explaining the result of FIG. In the present embodiment, the plasma processing apparatus according to the present invention is a plasma CV
The case where the present invention is applied to the D apparatus will be described.

The processing vessel 4 of the plasma CVD apparatus 2
In addition to the susceptor 6 as a lower electrode, is formed in a cylindrical shape, including a ceiling portion and a bottom portion, from a conductive material such as aluminum or stainless steel and is grounded. The susceptor 6 is formed, for example, in a substantially cylindrical shape having a central flat portion made of, for example, alumite-treated aluminum or the like, and a lower portion thereof is supported by a susceptor support 8 similarly formed in a columnar shape by aluminum or the like. And the susceptor support 8
Is installed at the bottom of the processing container 4 via an insulating material 10.

The susceptor 6 can be selectively connected to a high-frequency power supply 16 and a ground via a changeover switch 14 by a power supply path 12. And this susceptor 6
A semiconductor wafer W as an object to be processed is placed and held thereon by, for example, an electrostatic chuck mechanism (not shown).

A ceramic heater 18 for heating or adjusting the temperature of the wafer W on the susceptor 6 is provided between the susceptor 6 and the susceptor support 8, and the susceptor support 8 cools the heated wafer. For example, a cooling jacket 20 for flowing cooling water is provided for this purpose.

In the upper part of the processing chamber 4, an antenna member 22 made of, for example, copper and having a spiral shape of about one or two turns is provided. This antenna member 2
Numeral 2 is fixed to the ceiling by being sandwiched between an upper insulating plate 24 and a lower insulating plate 26 made of, for example, quartz for the purpose of insulating from the container ceiling and preventing heavy metal contamination by plasma sputtering. A matching box 30 and a high-frequency power supply 32 for generating electromagnetic waves are connected to both ends of the antenna member 22 via an insulated power supply line 28, so that electromagnetic waves can be emitted toward the processing space S. I have. An exhaust port 33 connected to a vacuum pump (not shown) is provided at the bottom of the processing container 4.
A gate valve (not shown) which can be opened and closed for loading and unloading the wafer W is provided on the side wall.

On the other hand, a raw material gas supply nozzle 34, which is a feature of the present invention, is radially inserted from eight directions from the side wall of the processing container 4 to introduce a raw material gas as a processing gas, for example, a silane gas. The nozzle insertion direction is not limited to eight directions, but may be any number as long as it is two or more directions, and they are arranged at substantially equal angles in the container circumferential direction.

Specifically, each of the supply nozzles 34 constitutes a supply passage for supplying a processing gas, and is formed in a pipe shape from an insulator such as quartz.
The nozzles 34A, 34B, and 34C are hermetically provided on the side wall in a plurality of stages along the vertical direction, for example, three stages in the illustrated example by a seal member (not shown) or the like. The number of nozzles is not limited to three, but may be two or more, depending on the wafer size. Each nozzle 34
The base ends of A, 34B, and 34C are connected via a gas supply pipe 38 to a processing gas source 40 that stores a source gas such as silane as a processing gas.

The processing gas injection holes 36 at the tips of the nozzles 34A, 34B, 34C provided in three stages are provided.
A, 36B, and 36C are located closer to the center of the processing container as being located in the upper stage. Therefore, the processing gas ejection hole 36B of the supply nozzle 34B of the upper stage (middle stage) is positioned closer to the center of the container than the processing gas ejection hole 36C of the lowermost supply nozzle 34C. Processing gas outlet 3 of supply nozzle 34A in upper stage (upper stage)
6A is further located on the container center side.

The gas ejection hole 36C of the lowermost supply nozzle 34C is located between the side wall of the processing container and the edge of the wafer, and is horizontally spaced from the gas ejection hole 36C.
The distance L1 between the wafer and the wafer edge is set to about 25 mm. This makes it possible to uniformly supply the source gas into the processing space on the wafer surface, thereby improving the in-plane uniformity of the film formation.

The uppermost processing gas supply nozzle 34A
Further, an additional gas supply nozzle 42 also made of quartz, which is arranged corresponding to each radial nozzle, is inserted through the upper side wall in the horizontal direction, and the base end of this nozzle is connected to the gas supply pipe 46. An additional gas, for example, an Ar gas source 48 for storing an Ar gas and an oxygen gas source 50 are connected via the gas source.
The additive gas ejection holes 44, which are the tips of the nozzles 42, are located above the processing gas ejection holes 36A, 36B, and 36C, respectively. Ar gas, oxygen gas, etc. ejected from the additive gas ejection holes 44 are provided. Can be efficiently and uniformly mixed with the source gas ejected from the processing gas ejection holes 36A, 36B, 36C located below.

Here, as described above, the processing gas outlet 36
The reason why the in-plane uniformity of film formation can be improved by providing a plurality of stages A, 36B, and 36C at the center of the container with respect to the ejection holes positioned at the upper stage will be described with reference to FIGS. I do. In FIG. 4, the case where the distance G in the vertical direction between the wafer W and the source gas supply nozzle 52 is changed and the case where the distance between the nozzle tip and the wafer edge is changed by changing the length L of the source gas supply nozzle 52 are respectively described. The in-plane uniformity of the film was examined. The distance between the container side wall and the wafer edge is set to 100 mm, and the wafer size is 5 inches.

First, the in-plane uniformity when the film was formed by changing the vertical distance G of the nozzle in various ways was evaluated. At this time, the distance between the tip of the nozzle and the wafer edge was set to 25 mm by fixing the length L of the nozzle to 75 mm. The result of the uniformity of the film thickness at this time is shown in FIG.

As is clear from FIG. 5, the greater the distance G in the vertical direction of the nozzle, the more the in-plane uniformity is improved.
Is set to about 75 mm or more, the uniformity of the film thickness becomes substantially constant. However, in this case, although not shown in the graph, the in-plane uniformity is improved, but the deposition rate of film formation is reduced, so that the distance G cannot be set excessively large.

Next, the vertical distance G of the nozzle is set to 75 m.
m, and the in-plane uniformity when the film was formed by changing the length L of the nozzle variously was evaluated. The result of the in-plane uniformity of the film thickness at this time is shown in FIGS. As is clear from the figure, the uniformity in the plane becomes better as the nozzle 52 is inserted from the container side wall into the inside, and when the distance L is 75 mm (the distance between the nozzle tip and the wafer edge is approximately 25 m).
m) It is found that the in-plane uniformity is the best, and the further the nozzle 52 is inserted, the more the in-plane uniformity deteriorates.

At this time, the film thickness in the wafer surface is represented by a distance L =
When actually examined at three points of 0, L = 75 and L = 100, the results shown in FIG. 7 were obtained. When the distance L = 0 mm as shown in FIG. 7A, the film thickness near the center of the wafer is too small, and when the distance L = 75 mm as shown in FIG. 7 (C), when the distance L = 100 mm, the film thickness near the center of the wafer and near the periphery of the wafer is small, and the film thickness in the middle portion is large. ing.

Therefore, in order to increase the film thickness in the vicinity of the center of the wafer, the tip of the nozzle is inserted to the center side of the container, and in order to suppress the influence on portions other than the vicinity of the center of the wafer, the tip of the nozzle is distant from the wafer surface. In order to increase the film thickness at the peripheral portion of the wafer to some extent, the tip of the nozzle is located at a position slightly separated in the horizontal direction from the wafer edge and lower than the nozzle position at the center of the wafer. It turns out that it is good to position.

For the above-described reasons, as described above, the processing gas ejection holes are provided in a plurality of stages, and as the ejection holes located on the upper stage are located closer to the center of the container, the film forming efficiency is improved. It becomes clear that the in-plane uniformity of the film formation can be improved while maintaining the state.

Next, the operation of the present embodiment configured as described above will be described. First, the semiconductor wafer W is housed in the processing container 4 by an arm (not shown) via a gate valve (not shown), and is placed and held on the susceptor 6.

The inside of the processing container 4 has an exhaust port 33.
The source gas supply nozzles 34A, 34B, and 34C supply a source gas such as silane from the source gas supply nozzles 34A, 34B, and 34C, and supply Ar gas from the additive gas supply nozzle 42 located above the source gas supply nozzles. By supplying an additive gas mixed with oxygen, the inside is maintained at a process pressure, for example, a considerably low pressure state of about 1 × 10 ⁻³ Torr, and at the same time, a high frequency of 13.56 MHz is supplied from the high frequency power supply 32 for plasma generation. Applied to the antenna member 32.

Then, an electromagnetic wave is emitted into the processing space S by the induction action of the inductance component of the antenna member 6, and at the same time, an alternating electric field is applied to the processing space S by the action of the capacitance component between the antenna member 6 and the processing container 4. As a result, Ar gas is excited in the processing space S to generate plasma, and as a result, the raw material gas and oxygen which are hardly thermally excited are activated to generate reactive species, and the SiO ₂ film is formed on the wafer. It will be deposited on the surface.

In this case, the plasma is 1 × 10 ⁻³ Torr to 1 × 10 ⁻⁶ T, as compared with the conventional parallel plate electrode type apparatus.
Since it is generated even under a very low pressure during orr, the scattering of reactive species during film formation is small, the directionality is uniform, and a film having a uniform thickness can be formed.

Particularly, in the present embodiment, the source gas supply nozzles 34A, 34B and 34C for supplying the source gas are provided in a plurality of stages, and the nozzle located at the upper stage is made longer and the processing gas injection hole at the tip thereof is formed. Is positioned on the center side of the processing space S, so that the source gas from the processing gas injection holes, for example, 36C, located near the peripheral portion of the wafer mainly contributes to film formation on the peripheral portion of the wafer, and Source gas from processing gas ejection holes located in the vicinity, for example, 36B and 36A, mainly contributes to film formation in the vicinity of an intermediate portion between the peripheral portion and the central portion of the wafer and in the vicinity of the central portion of the wafer. The film can be formed with good balance over the surface,
The in-plane uniformity of the film thickness can be greatly improved.

In this case, as the processing gas injection hole is located closer to the center of the processing space S, the injection holes are set at a higher position gradually separated from the wafer surface by forming the injection holes in a plurality of stages. The injection hole of the processing gas located on the center side, for example, the source gas from 36A is prevented from excessively contributing to the film formation, and as a result, the in-plane uniformity of the film thickness is significantly reduced as described above. Can be improved.

Further, in the present embodiment, the additional gas supply nozzles 42 of Ar gas or oxygen having a higher molecular weight than the source gas are connected to the respective source gas supply nozzles 34A, 34B,
Since it is located above 34C, the supplied source gas and additive gas are mixed well, and therefore, the in-plane uniformity of the film thickness can be further improved from this point. Therefore,
Even if the diameter of the wafer is increased, it is possible to cope with this. For example, the in-plane uniformity of the film thickness of the large diameter wafer of 8 inches or more can be improved.

Each of the supply nozzles 34 and 42 is inserted radially from the side wall, and the tip thereof is connected to the antenna member 2.
2, the electromagnetic power from the antenna member 22 is not absorbed so much, and this power can be efficiently contributed to plasma generation.

In the above embodiment, the case where the nozzles are inserted radially from eight directions as shown in FIG. 3 has been described as an example. However, the present invention is not limited to this. The number is not limited to three, four, five, six, seven directions, etc., as long as the number is evenly arranged along the circumferential direction of the processing container.

In the embodiment, the case where the source gas supply nozzles 34A, 34B and 34C are provided in three stages has been described as an example. However, the number of stages is not limited, and two or four or more stages are provided. You may make it set.

Further, in the above embodiment, the mixture of Ar gas and oxygen as the additive gas is introduced from the additive gas supply nozzle 42 into the container, but these gases are separately mixed without mixing. May be introduced independently from each of the nozzles.

Further, since the antenna member 22 is installed in the processing container 4, the radiated electromagnetic wave is reflected on the container wall and is used as electric power for plasma, so that the energy efficiency can be improved. Can be.

Further, in the above embodiment, the raw material gas supply nozzle 34 and the additive gas supply nozzle 42 are formed by inserting a pipe-shaped quartz nozzle therein, but the present invention is not limited to this. It may be configured as follows.
The same parts as those shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

FIGS. 8 and 9 are views showing an example of another gas supply method. The antenna member 2 is located at the upper part of the processing chamber 4 and covered with insulating plates 24 and 26 made of quartz glass.
Below the gas supply head 2, a gas supply head 54 is also provided in which a gas ejection surface 54A on the lower surface is formed in a dome shape using quartz glass.

In the gas supply head 54, raw gas supply passages 56A and 56B are formed along the horizontal direction in a plurality of stages in the vertical direction, in the illustrated example, two stages in the vertical direction. The processing gas ejection holes 58A and 58B are formed on the gas ejection surface 54A. Therefore, in this case as well, the processing gas ejection hole 58A of the upper source gas supply passage 56A is located closer to the center of the processing container than the processing gas ejection hole 58B of the lower source gas supply passage 56B. Will be done.

An additional gas supply passage 60 for introducing an additional gas is formed above the source gas supply passage 56A in the upper stage, similarly to the above-described embodiment. Upper processing gas injection hole 58A
Is formed as an additive gas ejection hole 62 further above. Also in this case, the processing gas ejection hole 58
A and 58B have the same effect as the apparatus shown in FIG. 2 and improve the in-plane uniformity of the thickness of the film formed because the ejection holes located at the upper stage are located closer to the center side in the processing container. It is also possible to cope with an increase in the diameter of the wafer.

In the example of the apparatus shown in FIG. 8, the source gas supply passages 56A, 56A,
Although 6B and the additional gas supply passage 60 are configured as gas passages as they are, the present invention is not limited to this. For example, as shown in an enlarged view of FIG. 9, metal gas pipes 64A and 64B are inserted through the gas supply passages 56A and 56B, A structure in which a gas flows therein may be used. In this case, the metal pipe 64
In order to avoid plasma sputtering on A and 64B, the tip of the pipe is slightly retracted so as not to protrude toward the processing space S from the processing gas ejection holes 58A and 58B at the ends of the gas supply passages 56A and 56B. Position. Then, each of the metal pipes 64A and 64B is connected to the ground so as not to generate plasma discharge. Although not shown in FIG. 9, the inside of the additive gas supply passage 60 is also
Needless to say, the configuration is the same as that in B.

In each of the above embodiments, each gas supply passage is formed substantially along the horizontal direction.
The tip of each gas supply passage may be formed to be bent downward toward the center of the susceptor.

In the embodiment shown in FIGS. 8 and 9, the case where the gas injection surface 54A of the gas supply head 54 is formed in a dome shape has been described. However, the present invention is not limited to this. For example, FIGS. It may be formed in a tapered shape as shown in FIG. FIG. 10 is a perspective view showing a modification of the gas supply head,
FIG. 11 is a sectional view of the gas supply head shown in FIG.

In this embodiment, the gas injection surface 54A inside the gas supply head 54 made of quartz glass is formed not in a dome shape but in a taper shape so as to form a part of a slope of a polygonal pyramid or a cone. This gas supply head 5
4, a plurality of, for example, two-stage source gas supply passages 56A and 56B and an additional gas supply passage 60 are provided in the same manner as shown in FIG.
Is provided. In particular, in this embodiment, the tip of each of the gas supply passages 56A, 56B, 60 is bent obliquely downward toward the center of the susceptor, and the ejected gas is efficiently transferred to the processing space S above the susceptor. From this point, it is possible to further improve the in-plane uniformity of the thickness of the film formed on the wafer.

In each of the embodiments described above,
The antenna member 22 covered by the insulating plates 24 and 26 is provided at the upper part in the processing chamber. However, the present invention is not limited to this, and the inside of the insulating member constituting the gas supply head as shown in FIGS. The antenna member may be embedded and covered. In FIG. 12, a gas supply head 54 made of quartz glass is formed into a dome shape having a predetermined thickness, and this head 54 can be vertically divided into two parts into an upper head part 66A and a lower head part 66B. I have.
The hemispherical lower surface of the lower head portion 66B is
4A.

The upper and lower heads 66
A spiral groove 68 capable of accommodating the antenna member 22 is provided at the joint of A and 66B, and the upper and lower heads 66A and 66B are joined with the antenna member 22 accommodated therein. The dome-shaped gas supply head 54 is provided with a plurality of, for example, two, stages of source gas supply passages 56A and 56B similar to those shown in FIG. 8, and an additional gas supply passage 60 is further provided thereon. . Thus, the processing gas ejection hole 58A at the end of the upper source gas supply passage 56A is positioned closer to the center of the processing container than the processing gas ejection hole 58B at the tip of the lower source gas supply passage 56B.

In this case, not only the same operation and effect as in FIG. 2 are exhibited, but also the antenna member 22 is incorporated in the gas supply head 54. Therefore, for example, the upper part required in the apparatus example shown in FIG. And lower insulating plates 24, 2
6 can be dispensed with and the structure can be simplified.

In FIG. 13, a tapered gas supply head 54 having a predetermined thickness is provided instead of the dome-shaped gas supply head 54 having a predetermined thickness shown in FIG. Also in this case, the tapered gas supply head 54 having a predetermined thickness can be vertically separated into an upper head portion 66A and a lower head portion 66B, and the antenna member 22 is interposed between these joint portions. The head 54 is provided with a plurality of stages of source gas supply passages 56A and 56B, and the upper stage is provided with an additional gas supply passage 60 in the same structure as the embodiment shown in FIG.

In the conventional shower head structure, the film adheres to the step formed near the gas ejection port and causes particles, but as described above, the gas ejection surface has a dome shape or a tapered shape. By doing so, there is no stepped portion in the vicinity of the gas ejection port, and film formation can be prevented, which can contribute to particle reduction.

In each of the above embodiments, the gas ejection surface is dome-shaped or tapered so that the upper processing gas ejection hole is located closer to the center of the processing vessel than the lower processing gas ejection hole. However, the shape of the gas ejection surface is not limited to the one described above as long as the positional relationship of the ejection holes is satisfied. For example, the gas ejection surface may be formed in a step shape.

Further, in each of the above embodiments, the case where the source gas supply passage and the additional gas supply passage are inserted or supplied from the side wall side in the processing container has been described. However, the present invention is not limited to this. As shown in FIG. 14, an antenna member 22 sandwiched between upper and lower insulating plates 24 and 26 is provided on a ceiling portion of the processing container 4 and a gas such as quartz glass for supplying a raw material gas or an additional gas from the ceiling portion. The supply head 70 may be suspended so as to have a shower head structure. In this case, in the usual conventional shower head structure, the gas ejection surface on the lower surface facing the lower electrode is formed in a flat plate shape. In this embodiment, the gas ejection surface 54A is, for example, as shown in FIGS. The gas ejection surface 54A is formed in a dome shape similarly to the structure shown.
Are formed with a plurality of processing gas ejection holes 58A and 58B. Therefore, also in this case, of the processing gas ejection holes, the ejection hole 58A located on the upper stage side is replaced with the ejection hole 58B located on the lower stage side.
8 and 12 are located on the center side of the processing container.
The same operation and effect as the structure shown in FIG.
In this case, a large number of diffusion holes 7 are provided in the gas supply head 70.
By providing one or two diffusing plates 74A and 74B having the number 2, the supply amount of the supply gas to the processing space S can be made uniform.

In each of the above embodiments, the case where the antenna member 22 is accommodated in the container has been described.
This may be shielded and positioned outside the container, for example, on the upper surface side of the ceiling. In each embodiment, silane gas (SiH ₄ ) was used as a raw material gas.
The case where Ar gas and oxygen are used as the additive gas has been described as an example, but it is a matter of course that the present invention is not limited to these gases.

[0062]

As described above, according to the plasma processing apparatus of the present invention, the following excellent operational effects can be exhibited. Since the processing gas ejection holes are provided in a plurality of stages in the processing container and the processing gas ejection holes located on the upper stage side are located closer to the center of the processing container than the processing gas ejection holes located on the lower stage side. The concentration of plasma and the concentration of reactive species above the object to be processed can be made uniform,
Therefore, the in-plane uniformity of the thickness of the film formed on the surface of the object can be significantly improved. Therefore, even if the diameter of the object to be processed becomes large, it is possible to cope with this by providing the processing gas ejection holes in a plurality of stages, and the in-plane uniformity of the film thickness can be maintained high. By providing a plurality of processing gas injection holes in the gas supply head having a dome-shaped or tapered gas injection surface, the upper processing gas injection hole is more similar to the lower processing gas injection hole in the processing container as described above. It is located on the center side, and as a result, the in-plane uniformity of the film thickness can be similarly improved. Further, by providing the additional gas ejection hole on the upper side of the processing gas ejection hole, the processing gas (raw material gas) introduced into the processing vessel and the additional gas can be uniformly mixed, and therefore, the film thickness can be reduced. In-plane uniformity can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a plasma processing apparatus according to the present invention.

FIG. 2 is a sectional view of the processing apparatus shown in FIG.

FIG. 3 is a plan view of the processing apparatus shown in FIG. 1;

FIG. 4 is a diagram showing a positional relationship between a nozzle and a wafer in order to evaluate film formation with respect to a gas supply nozzle position.

FIG. 5 is a graph showing in-plane uniformity of a film thickness with respect to a distance in a height direction between a nozzle tip and a wafer.

FIG. 6 is a graph showing in-plane uniformity of a film thickness with respect to a nozzle length.

FIG. 7 is an explanatory diagram for explaining a result of the graph shown in FIG. 6;

FIG. 8 is a schematic sectional view showing an apparatus of the present invention in which a gas ejection surface is formed in a dome shape.

FIG. 9 is an enlarged view of a main part showing a modified example of the device shown in FIG.

FIG. 10 is a perspective view showing a gas supply head having a gas ejection surface formed in a tapered shape.

11 is a sectional view of the gas supply head shown in FIG.

FIG. 12 is a schematic sectional view showing an example of the apparatus of the present invention in which the gas supply head itself is formed in a dome shape.

FIG. 13 is a schematic sectional view showing an example of the apparatus of the present invention in which the gas supply head itself is formed into a tapered shape.

FIG. 14 is a schematic cross-sectional view showing an example of the apparatus of the present invention in which a gas ejection surface of a gas supply head suspended from a ceiling has a dome shape.

[Explanation of symbols]

 2 Plasma CVD apparatus (plasma processing apparatus) 4 Processing vessel 6 Susceptor (lower electrode) 8 Susceptor support 22 Antenna member 24 Upper insulating plate 26 Lower insulating plate 32 High frequency power supply 34 Source gas supply nozzle 34A Upper source gas supply nozzle 34B Middle source Gas supply nozzle 34C Lower raw material gas supply nozzle 36A, 36B, 36C Processing gas ejection hole 40 Processing gas source 48 Ar gas source 50 Oxygen gas source 54 Gas supply head 54A Gas ejection surface 56A, 56B Source gas supply passage 58A, 58B Processing gas Spouting hole 66A Upper head part 66B Lower head part 70 Shower head 74A, 74B Diffusion plate W Semiconductor wafer (workpiece)

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shuichi Ishizuka 5-36 Akasaka, Minato-ku, Tokyo Inside TBS Transmission Center Tokyo Electron Co., Ltd. (72) Inventor Jiro Hata 5-3-1 Akasaka, Minato-ku, Tokyo No. 6 TBS Release Center Tokyo Electron Limited F term (reference) 4G075 AA24 BC04 BD03 BD14 CA02 CA03 CA25 CA47 CA62 DA01 DA02 EB01 EB42 EC03 FB02 FB06 FC11 4K030 CA04 CA12 EA06 FA04 KA30 5F045 AA08 AB32 AC01 AC11 AC16 AE02 DQ10 EB02 EF02 EF04 EF08 EF20 EH02 EH11 EH20

Claims (5)

[Claims] 1. A plasma processing apparatus disposed in an airtight processing container and performing plasma processing on an object to be processed mounted on a susceptor, comprising: an antenna member provided outside the processing container; A high-frequency power supply connected to the antenna member, a plurality of processing gas supply passages, and a gas supply unit for supplying a processing gas into the processing container from a processing gas ejection hole communicating with the processing gas supply passage; An exhaust port for exhausting the inside of the processing container, wherein the gas supply unit is disposed above the surface of the object to be processed, and the position of the processing gas ejection hole communicating with the processing gas supply passage is set to the processing position. A plasma processing apparatus, which is located in a circumferential direction of a container and is arranged substantially uniformly, and discharges a processing gas toward a central portion in the processing container. 2. A plasma processing apparatus which is disposed in an airtight processing container and performs plasma processing on an object mounted on a susceptor, wherein: an antenna member provided outside the processing container; A high-frequency power supply connected to an antenna member, a mounting table that holds the object to be processed and is heatable in the processing container, and a plurality of processing gas supply passages, and a processing gas jet that communicates with the processing gas supply passage. A gas supply unit for supplying a processing gas from the hole into the processing container, and an exhaust port for exhausting the inside of the processing container, wherein the gas supply unit is disposed above the surface of the object to be processed. The position of the processing gas ejection hole that communicates with the processing gas supply passage is located in the circumferential direction of the processing container, and is disposed substantially uniformly, and discharges the processing gas toward a central portion in the processing container. Specially Plasma processing equipment. 3. The plasma processing apparatus according to claim 1, wherein the gas supply unit is a nozzle. 4. The plasma processing apparatus according to claim 1, wherein the gas supply unit is a gas supply head. 5. The plasma processing apparatus according to claim 4, wherein the gas supply section has a dome-shaped or tapered shape on a gas ejection hole surface side.