JP2006100838A - Plasma treatment device - Google Patents

Abstract

<P>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. <P>SOLUTION: In this plasma treatment device, plasma treatment is made to the wafer W to be treated, and is arranged in an airtight treatment container 4, and is placed on a susceptor 6. The plasma treatment device has an antenna member 22, 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 the 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 vessel. The treatment gas jet hole, communicating with the treatment gas supply path, is positioned in the circumferential direction of the treatment vessel, is arranged nearly uniformly and discharges the treatment gas toward the center section in the treatment vessel, thus significantly improving the in-plane uniformity in the thickness in deposition. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plasma processing apparatus, and more particularly to a plasma processing apparatus for forming a film.

  In general, in a semiconductor manufacturing process, various types of processing, such as film formation processing, are performed on a semiconductor wafer as an object to be processed. As this film formation method, plasma using a combination of chemical and physical methods. CVD (Chemical Vapor Deposition) is known.

  A plasma processing apparatus that performs this processing, for example, places two flat electrodes in a processing container in parallel, and applies a high frequency voltage of 13.56 MHz, for example, from a high frequency power source for plasma generation between them. Plasma is generated, whereby the wafer surface is subjected to processing such as etching.

  As described above, the plasma generated between the parallel plate electrodes is an alternating magnetic field directed from one electrode to the other, so electrons are attracted along this electric field and collide with gas molecules. As a result, the gas that is hardly thermally excited is activated to perform a desired film formation.

By the way, forming a film with a uniform thickness on the wafer surface is very important for improving the yield of semiconductor products, but the thickness of the film is greatly influenced by the method of supplying the source gas. Is the actual situation.
As this source gas supply method, a supply nozzle is inserted into the inside from the side wall of the processing vessel, and a source gas is supplied toward the wafer surface from this, or a flat shower head structure is provided on the upper electrode, From this, a method of supplying a source gas toward the wafer surface side is known.

However, as described above, simply supplying the source gas from the side wall of the processing chamber makes it difficult for the reactive species that contribute to film formation to reach the vicinity of the center of the wafer sufficiently, and it is possible to form a film with a uniform thickness on the wafer surface. was difficult.
In addition, in a simple flat shower head structure, the flow of the supply gas may be disturbed, and in this case as well, it is relatively difficult to ensure the uniformity of the film thickness within the wafer surface.

  In addition, in the previous application (Japanese Patent Application No. 5-317375), the present inventor provided an antenna member in the upper part of the processing container or outside of the ceiling part, and so-called inductively coupled plasma that induces plasma by electromagnetic waves from now on. A forming method was proposed.

According to this, since 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, the processing characteristics of plasma etching and plasma film formation processing can be improved. When the above-described shower head structure is adopted in the inductively coupled plasma processing apparatus, a part of the electromagnetic wave from the antenna member is absorbed by the shower head structure made of a dielectric, leading to a decrease in plasma generation efficiency. End up. Therefore, in the case of an inductively coupled plasma processing apparatus, a raw material gas or the like must be introduced from the side wall of the processing vessel in order to prevent a decrease in plasma generation efficiency. There has been a problem in that it is impossible to ensure sufficient uniformity.
In particular, when a semiconductor wafer becomes large in diameter and becomes a large wafer such as an 8-inch wafer, it becomes a big problem to make the gas concentration uniform between the central portion and the peripheral portion of the wafer.

  The present invention has been devised to pay attention to the above problems and to effectively solve them. An object of the present invention is to provide a plasma processing apparatus capable of improving the in-plane uniformity of the film thickness even if the object to be processed has a large diameter.

  As a result of diligent research, the present inventor has found that when the source gas is introduced from the side wall of the processing vessel, the distance between the nozzle tip and the wafer edge greatly affects the in-plane uniformity of the film formation, and the wafer diameter is increased. Accordingly, the present invention has been made by obtaining the knowledge that in order to supply a gas having a uniform concentration to the center of the wafer, it is preferable to provide ejection holes over a plurality of stages.

  In order to solve the above-mentioned problems, a first invention is a plasma processing apparatus that is disposed in an airtight processing container and performs plasma processing on an object to be processed placed on a susceptor. An antenna member provided outside, a high-frequency power source connected to the antenna member, and a plurality of processing gas supply passages, and processing gas is introduced into the processing container from a processing gas ejection hole communicating with the processing gas supply passage. A gas supply unit for supplying gas 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 communicates with the processing gas supply passage. The plasma processing apparatus is characterized in that the processing gas ejection holes are positioned in the circumferential direction of the processing container, are arranged substantially evenly, and the 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 which is disposed in an airtight processing container and placed on a susceptor, and an antenna member provided outside the processing container; A processing gas that includes a high-frequency power source connected to the antenna member, a mounting table that holds and heats an object to be processed in the processing container, and a plurality of processing gas supply passages, and communicates with the processing gas supply passage A gas supply unit for supplying a processing gas from the ejection hole into the processing container; and an exhaust port for exhausting the processing container; and the gas supply unit is disposed above the surface of the object to be processed. The processing gas ejection holes communicating with the processing gas supply passage are located in the circumferential direction of the processing container and are arranged substantially evenly to discharge the processing gas toward the central portion in the processing container. Features to do It is a plasma processing apparatus for.

  In this case, for example, as defined in claim 3, the gas supply unit is a nozzle. For example, as defined in claim 4, the gas supply unit is a gas supply head. Further, for example, as defined in claim 5, the gas supply port has a dome shape or a tapered shape on the gas ejection hole surface side.

<Action>
Since the present invention is configured as described above, the processing gas supplied from the processing gas ejection hole is excited by the electromagnetic wave from the antenna member connected to the high frequency power source, 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 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 stage side mainly contributes to the film formation on the peripheral portion of the object to be treated, and the source gas from the processing gas ejection hole located on the upper stage side mainly. This contributes to film formation in the vicinity of the center of the object to be processed. Therefore, the in-plane uniformity of the film formed as a whole can be improved.
In this case, in order to form the processing gas supply passage, a plurality of supply nozzles extending radially from the side wall of the processing container may be provided.

Further, by providing an additive gas injection hole for supplying an additive gas such as Ar gas or oxygen above the above-described process gas injection hole, the additive gas and the process gas can be mixed more uniformly. The uniformity can be further enhanced.
Further, as a processing gas supply method, a gas supply head having a gas dome-shaped or tapered surface is provided in the processing container as in the second or third invention, and the gas jetting surface is processed in a plurality of stages. Gas ejection holes can also be provided.

  According to this, similarly to the first invention, the processing gas ejection hole located on the upper stage side is located closer to the center side of the processing container than the processing gas ejection hole located on the lower stage side. The same effects as those of the first invention can be exhibited.

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 positioned closer to the center side of the processing container than the processing gas ejection holes located on the lower stage side, The plasma concentration and the concentration of reactive species above the object to be processed can be made uniform, and therefore the in-plane uniformity of the thickness of the film formed on the surface of the object to be processed can be greatly improved.
Therefore, even if the diameter of the object to be processed becomes large, it is possible to cope with this by providing a plurality of process gas ejection holes, and the in-plane uniformity of the film thickness can be kept high.
By providing a gas supply head having a dome-shaped or tapered gas supply surface with a plurality of stages of process gas injection holes, the upper process gas injection holes are located closer to the process vessel than the lower process gas injection holes as described above. As a result, the in-plane uniformity of the film thickness can be similarly improved.
Further, by providing the additive gas ejection hole on the upper stage side of the treatment gas ejection hole, the treatment gas (raw material gas) introduced into the treatment container and the additive gas can be mixed uniformly, and therefore the film thickness is increased. In-plane uniformity can be further improved.

Hereinafter, an embodiment of a plasma processing apparatus according to the present invention will be described 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 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 is a graph showing the positional relationship between the nozzle and the wafer in order to evaluate the film formation, FIG. 5 is a graph showing the in-plane uniformity of the film thickness with respect to the distance in the height direction of the nozzle tip and the wafer, and FIG. 6 is the length of the nozzle. FIG. 7 is an explanatory diagram for explaining the results of the graph shown in FIG. 6.
In this embodiment, the case where the plasma processing apparatus according to the present invention is applied to a plasma CVD apparatus will be described.

The processing container 4 of the plasma CVD apparatus 2 is formed into a cylindrical shape with a conductive material such as aluminum or stainless steel, including the ceiling and bottom, and is grounded, and a susceptor 6 serving as a lower electrode is provided inside the processing container 4. Is installed.
The susceptor 6 is formed into a substantially cylindrical shape with a central portion made convex, for example, by anodized aluminum or the like, and the lower part is supported by a susceptor support base 8 that is also made cylindrical by aluminum or the like. In addition, the susceptor support 8 is installed on the bottom of the processing container 4 via an insulating material 10.

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

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

Further, for example, a copper antenna member 22 made of a spiral of about one turn or two turns is provided in the upper part of the processing container 4. The antenna member 22 is sandwiched between an upper insulating plate 24 and a lower insulating plate 26 made of, for example, quartz and fixed to the ceiling portion for the purpose of insulation from the container ceiling portion and prevention of heavy metal contamination due to plasma sputtering. A matching box 30 and a high-frequency power source 32 for generating electromagnetic waves are connected to both ends of the antenna member 22 via insulated feed lines 28 so that electromagnetic waves can be radiated toward the processing space S. Yes.
In addition, an exhaust port 33 connected to a vacuum pump (not shown) is provided at the bottom of the processing container 4, and a gate valve (not shown) that can be opened and closed to load and unload the wafer W is provided on the side wall. Provided.

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

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

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

  Further, the gas ejection hole 36C of the lowermost supply nozzle 34C is positioned between the side wall of the processing vessel and the edge of the wafer, and the distance L1 between the gas ejection hole 36C and the wafer edge is set to a horizontal distance of 25 mm. Set to degree. As a result, the source gas can be uniformly supplied into the processing space on the wafer surface to improve the in-plane uniformity of the film formation.

  Further, on the upper side wall of the uppermost processing gas supply nozzle 34A, an additive gas supply nozzle 42 made of quartz, which is arranged corresponding to each radial nozzle, is inserted in the horizontal direction. The proximal end portion is connected to an Ar gas source 48 and an oxygen gas source 50 for storing an additive gas, for example, Ar gas, through a gas supply pipe 46. The additive gas ejection hole 44, which is the tip of the nozzle 42, is positioned above the processing gas ejection holes 36A, 36B, 36C, and Ar gas, oxygen gas, etc. ejected from the additive gas ejection hole 44, etc. The additive gas can be efficiently and uniformly mixed with the raw material gas ejected from the processing gas ejection holes 36A, 36B, and 36C located below.

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

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

  As is apparent from FIG. 5, the in-plane uniformity improves as the distance G in the vertical direction of the nozzle increases, and the uniformity of the film thickness can be made substantially constant by setting the distance G to about 75 mm or more. Prove. However, in this case, although not shown in the graph, the in-plane uniformity is improved, but the deposition rate of the film formation is lowered, so the distance G cannot be set too large.

Next, the in-plane uniformity when the film was formed while fixing the distance G in the vertical direction of the nozzle to 75 mm and changing the length L of the nozzle in various ways was evaluated. The results of in-plane uniformity of film thickness at this time are shown in FIGS.
As is apparent from the figure, the in-plane uniformity becomes better as the nozzle 52 is inserted into the container from the side wall of the container. When the distance L is 75 mm (the distance between the nozzle tip and the wafer edge is about 25 mm), the in-plane uniformity is the best. It becomes clear that the in-plane uniformity is deteriorated as the nozzle 52 is further inserted.

When the film thickness in the wafer surface at this time was actually examined at three points of distances L = 0, L = 75, and L = 100, results as shown in FIG. 7 were obtained.
When the distance L = 0 mm as shown in FIG. 7A, the film thickness near the wafer center is too small, and when the distance L = 75 mm as shown in FIG. As shown in FIG. 7C, when the distance L = 100 mm, the film thickness in the vicinity of the wafer center and in the vicinity of the wafer periphery is small, and the film thickness in the intermediate portion is large. ing.

  Therefore, to increase the film thickness near the wafer center, insert the nozzle tip as far as the center of the container, and keep the nozzle tip far away from the wafer surface in order to suppress the effect on parts other than the vicinity of the wafer center. Also, in order to increase the film thickness around the wafer to some extent, the tip of the nozzle is positioned at a position slightly away from the wafer edge in the horizontal direction and lower than the nozzle position on the center side. Turns out to be good.

  For the reasons described above, as described above, the process gas ejection holes are provided in a plurality of stages, and the film ejection efficiency is maintained high by positioning the ejection holes located on the upper stage side and the container center side. It becomes clear that the in-plane uniformity of film formation can be improved.

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

Then, the inside of the processing container 4 is evacuated by evacuating from the exhaust port 33, and a raw material gas such as silane is supplied from each of the raw material gas supply nozzles 34A, 34B, and 34C and positioned above this. From the additive gas supply nozzle 42, an additive gas mixed with Ar gas and oxygen is supplied to maintain the inside at a process pressure, for example, a considerably low pressure of about 1 × 10 ⁻³ Torr. For example, a high frequency of 13.56 MHz is applied to the antenna member 32 from the high frequency power supply 32.

Then, electromagnetic waves are emitted to the processing space S by the induction effect of the inductance component of the antenna member 6, and at the same time, an alternating electric field is generated in the processing space S by the action of the capacitive 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, a source gas and oxygen that are difficult to be thermally excited are activated to generate reactive species, and a SiO ₂ film is deposited on the wafer surface. Will do.

In this case, the plasma is generated even under a considerably low pressure between 1 × 10 ⁻³ Torr and 1 × 10 ⁻⁶ Torr as compared with the conventional parallel plate electrode type apparatus. Therefore, the film has a uniform direction and can be formed with a uniform thickness.

  In particular, in this embodiment, the raw material gas supply nozzles 34A, 34B, 34C for supplying the raw material gas are provided in a plurality of stages, and the nozzle located in the upper stage is made longer so that the processing gas injection hole at the tip thereof is formed in the processing space. Since it is positioned on the center side of S, the process gas injection holes located near the wafer peripheral portion, for example, the source gas from 36C mainly contributes to the film formation on the wafer peripheral portion and is located near the wafer central portion. The source gas from the processing gas ejection holes, for example, 36B and 36A, mainly contributes to the film formation in the vicinity of the 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 in a well-balanced manner, and the in-plane uniformity of the film thickness can be greatly improved.

  In this case, as the processing gas injection holes are positioned closer to the center of the processing space S, the injection holes are installed at higher positions gradually away from the wafer surface by using a plurality of stages. The source gas from the processing gas injection hole located, for example, 36A is prevented from contributing excessively to the film formation, and as a result, the in-plane uniformity of the film thickness is greatly improved as described above. Can do.

Furthermore, in the present embodiment, the additive gas supply nozzle 42 such as Ar gas or oxygen having a molecular weight larger than that of the source gas is positioned above the source gas supply nozzles 34A, 34B, 34C. Thus, the in-plane uniformity of the film thickness can be further improved than this point.
Therefore, even if the diameter of the wafer is increased, this can be dealt with. For example, the in-plane uniformity of the film thickness of a large diameter wafer of 8 inches or more can be improved.

  Further, the supply nozzles 34 and 42 are respectively inserted radially from the side walls so that the tip thereof is not positioned below the antenna member 22, so that electromagnetic waves from the antenna member 22 are not absorbed much. This electric power can contribute to plasma generation efficiently.

  In the above embodiment, the case where the nozzles are provided radially from eight directions as shown in FIG. 3 has been described as an example. However, the present invention is not limited to this, and the nozzles of the cylindrical processing container are provided. As long as they are arranged uniformly along the circumferential direction, the number is not limited to 3, 4, 5, 6, 7 and the like.

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

  Furthermore, in the above embodiment, Ar gas and oxygen are mixed as additive gas and introduced from the additive gas supply nozzle 42 into the container. However, these additive gases can be mixed from separate nozzles without mixing. You may make it introduce each independently.

  Furthermore, since the antenna member 22 is installed in the processing container 4, the radiated electromagnetic waves are reflected on the container wall and used as electric power for plasmatization, so that energy efficiency can be improved.

  Further, in the above-described embodiment, a pipe-like quartz nozzle is inserted into the inside as the source gas supply nozzle 34 and the additive gas supply nozzle 42, but the present invention is not limited to this and is as follows. It may be configured. 2 that are the same as those shown in FIG.

  FIGS. 8 and 9 are diagrams showing an example of another gas supply method. In the upper part of the processing container 4 and below the antenna member 22 covered with the insulating plates 24 and 26 made of quartz glass, Similarly, a gas supply head 54 in which a gas ejection surface 54A on the lower surface is formed in a dome shape by quartz glass is provided.

  In the gas supply head 54, raw material gas supply passages 56A and 56B are formed along a horizontal direction in a plurality of stages in the vertical direction, and in the illustrated example in two stages in the vertical direction, and the tip of each passage is a gas ejection surface. 54A is configured as process gas ejection holes 58A and 58B. Accordingly, also in this case, the processing gas ejection hole 58A of the raw material gas supply passage 56A located in the upper stage is located closer to the center side in the processing container than the processing gas ejection hole 58B of the raw material gas supply passage 56B located in the lower stage. Will be.

  An additive gas supply passage 60 for introducing additive gas is formed above the upper raw material gas supply passage 56A, as in the above-described embodiment, and the tip of the additive gas supply passage 60 is an upper treatment at the gas ejection surface 54A. The additive gas ejection hole 62 is configured further above the gas ejection hole 58A. Also in this case, since the processing gas ejection holes 58A and 58B are located closer to the center side in the processing container as the ejection holes located in the upper stage, the same effect as the apparatus shown in FIG. In-plane uniformity of thickness can be improved, and it is possible to cope with an increase in wafer diameter.

  Further, in the apparatus example shown in FIG. 8, the raw material gas supply passages 56A and 56B and the additive gas supply passage 60 formed in the gas supply head 54 are configured as gas passages as they are. As shown in the enlarged view of FIG. 9, metal pipes 64A and 64B may be inserted into the gas supply passages 56A and 56B, and the gas may flow therethrough. In this case, in order to avoid plasma sputtering on the metal pipes 64A and 64B, the pipe tips do not protrude from the process gas ejection holes 58A and 58B at the tips of the gas supply passages 56A and 56B to the process space S side. It is located in a position slightly retracted. Each of the metal pipes 64A and 64B is connected to the ground so that plasma discharge does not occur. Although not shown in FIG. 9, the additive gas supply passage 60 is of course configured in the same manner as the source gas supply passages 56A and 56B.

  Further, in each of the above embodiments, each gas supply passage is entirely formed along a substantially horizontal direction, but the tip of each gas supply passage is bent downward toward the center direction of the susceptor. You may form in this way.

  In the embodiment shown in FIGS. 8 and 9, the case where the gas injection surface 54 </ b> A 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, as shown in FIGS. 10 and 11. You may form in a taper shape. FIG. 10 is a perspective view showing a modification of the gas supply head, and FIG. 11 is a cross-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 in a tapered shape so as to form a polygonal pyramid or a part of a conical slope instead of a dome shape. The gas supply head 54 is provided with a plurality of stages, for example, two stages of source gas supply passages 56A and 56B and an additive gas supply passage 60, as shown in FIG. In particular, in this embodiment, the distal ends of the gas supply passages 56A, 56B, 60 are bent obliquely downward toward the center direction of the susceptor, and the ejected gas is efficiently introduced into 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.

  Further, in each of the embodiments described above, the antenna member 22 covered with the insulating plates 24 and 26 is provided in the upper part in the processing container. However, the present invention is not limited to this, and FIGS. As shown in FIG. 4, the antenna member may be embedded and covered in an insulating member constituting the gas supply head. In FIG. 12, a quartz glass gas supply head 54 is formed into a dome shape having a predetermined thickness, and the head 54 can be divided into an upper head portion 66A and a lower head portion 66B in the vertical direction. Yes. A hemispherical lower surface of the lower head portion 66B is configured as a gas ejection surface 54A.

Then, a spiral groove 68 capable of accommodating the antenna member 22 is provided at a joint portion between the upper and lower head portions 66A and 66B, and the upper and lower head portions 66A and 66B are accommodated in the state where the antenna member 22 is accommodated. Join.
Further, the dome-shaped gas supply head 54 is provided with a plurality of raw material gas supply passages 56A and 56B similar to those shown in FIG. 8, for example, two stages, and further, an additive gas supply passage 60 is provided on the upper stage. . As a result, the processing gas ejection hole 58A at the tip of the upper stage source gas supply passage 56A is positioned closer to the center of the processing vessel than the processing gas ejection hole 58B at the tip of the lower stage source gas supply passage 56B.

  In this case as well, not only the effects similar to those of FIG. 2 are exhibited, but also the antenna member 22 is incorporated in the gas supply head 54, so that, for example, the upper and lower insulations required in the apparatus example shown in FIG. The plates 24 and 26 can be omitted, and the structure can be simplified.

  13 is provided with a tapered gas supply head 54 having a predetermined thickness 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 separated into the upper head portion 66A and the lower head portion 66B in the vertical direction, and the antenna member 22 is interposed between these joint portions. The head 54 is provided with the raw material gas supply passages 56A and 56B over a plurality of stages, and the additive gas supply passage 60 is provided on the upper stage, which is the same structure as the embodiment shown in FIG.

  In addition, in the conventional showerhead structure, a film adheres to the stepped portion in the vicinity of the gas outlet and causes particles. However, as described above, the gas ejection surface should be dome-shaped or tapered. This eliminates the step portion in the vicinity of the gas outlet and prevents film formation, thereby contributing to the reduction of particles.

  In each of the above embodiments, the gas ejection surface is formed in a dome shape or a taper shape so that the upper process gas ejection hole is positioned closer to the center of the process vessel than the lower process gas ejection hole. As long as the positional relationship of the ejection holes is satisfied, the shape of the gas ejection surface is not limited to that described above, and may be formed in a stepped step shape, for example.

  Further, in each of the above-described embodiments, the case where the source gas supply passage and the additive 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. Thus, the antenna member 22 sandwiched between the upper and lower insulating plates 24 and 26 is provided in the ceiling portion of the processing container 4, and a gas supply head 70 made of, for example, quartz glass for supplying source gas and additive gas from the ceiling portion. It is good also as a shower head structure so that it may suspend and support. In this case, in the conventional conventional showerhead 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. Similar to the structure shown, it is shaped like a dome, and a plurality of process gas ejection holes 58A, 58B are formed in this gas ejection surface 54A. Therefore, also in this case, among the processing gas ejection holes, the ejection hole 58A located on the upper stage side is located closer to the center side of the processing container than the ejection hole 58B located on the lower stage side. The same effect as the structure shown can be exhibited. In this case, by providing one or two diffusion plates 74A and 74B having a large number of diffusion holes 72 in the gas supply head 70, the supply amount of the supply gas to the processing space S can be made uniform. it can.

In each of the above embodiments, the case where the antenna member 22 is accommodated in the container has been described. However, the antenna member 22 may be shielded and positioned outside the container, for example, on the upper surface side of the ceiling portion.
In each embodiment, silane gas (SiH ₄ ) is used as a source gas and Ar gas and oxygen are used as additive gases. However, the present invention is not limited to these gases.

As described above, 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 side of the processing container than the processing gas ejection holes located on the lower stage side. As a result, the plasma concentration and the concentration of reactive species above the object to be processed can be made uniform, and therefore the in-plane uniformity of the thickness of the film formed on the surface of the object to be processed can be greatly increased. Can be improved.
Therefore, even if the diameter of the object to be processed becomes large, it is possible to cope with this by providing a plurality of process gas ejection holes, and the in-plane uniformity of the film thickness can be kept high.
By providing a gas supply surface having a dome-shaped or tapered gas supply surface with a plurality of stages of process gas ejection holes, the upper process gas ejection holes are located closer to the process vessel than the lower process gas ejection holes as described above. As a result, the in-plane uniformity of the film thickness can be similarly improved.
Further, by providing the additive gas ejection hole on the upper stage side of the treatment gas ejection hole, the treatment gas (raw material gas) introduced into the treatment container and the additive gas can be mixed uniformly, and therefore the film thickness is increased. In-plane uniformity can be further improved.

1 is a schematic perspective view showing a plasma processing apparatus according to the present invention. It is sectional drawing of the processing apparatus shown in FIG. It is a top view of the processing apparatus shown in FIG. It is a figure which shows the positional relationship of a nozzle and a wafer in order to evaluate the film-forming with respect to a gas supply nozzle position. It is a graph which shows the in-plane uniformity of the film thickness with respect to the distance of the nozzle front-end | tip and the height direction of a wafer. It is a graph which shows the in-plane uniformity of the film thickness with respect to the length of a nozzle. It is explanatory drawing for demonstrating the result of the graph shown in FIG. It is a schematic sectional drawing which shows the apparatus of this invention which formed the gas ejection surface in the dome shape. It is a principal part enlarged view which shows the modification of the apparatus shown in FIG. It is a perspective view which shows the gas supply head in which the gas ejection surface was formed in the taper shape. It is sectional drawing of the gas supply head shown in FIG. It is a schematic sectional drawing which shows the example of an apparatus of this invention which shape | molded gas supply head itself in the dome shape. It is a schematic sectional drawing which shows the example of an apparatus of this invention which shape | molded gas supply head itself in the taper shape. It is a schematic sectional drawing which shows the example of an apparatus of this invention which made the gas ejection surface of the gas supply head suspended from the ceiling part the dome shape.

Explanation of symbols

2 Plasma CVD equipment (plasma processing equipment)
4 Processing container 6 Susceptor (lower electrode)
8 susceptor support base 22 antenna member 24 upper insulating plate 26 lower insulating plate 32 high frequency power supply 34 raw material gas supply nozzle 34A upper raw material gas supply nozzle 34B middle raw material gas supply nozzle 34C lower raw material gas supply nozzle 36A, 36B, 36C processing gas ejection hole 40 Process gas source 48 Ar gas source 50 Oxygen gas source 54 Gas supply head 54A Gas ejection surface 56A, 56B Raw material gas supply passage 58A, 58B Process gas ejection hole 66A Upper head part 66B Lower head part 70 Shower head 74A, 74B Diffusion Plate W Semiconductor wafer (object to be processed)

Claims (5)

In a plasma processing apparatus that is disposed in an airtight processing container and performs plasma processing on an object to be processed placed on a susceptor,
An antenna member provided outside the processing container;
A high-frequency power source connected to the antenna member;
A gas supply unit that includes a plurality of process gas supply passages and supplies process gas into the process container from a process gas ejection hole communicating with the process gas supply passage;
An exhaust port for exhausting the inside of 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 holes communicating with the processing gas supply passage is positioned in the circumferential direction of the processing container, and is disposed substantially evenly. A plasma processing apparatus that discharges a processing gas toward a central portion in the processing container. In a plasma processing apparatus that is disposed in an airtight processing container and performs plasma processing on an object to be processed placed on a susceptor,
An antenna member provided outside the processing container;
A high-frequency power source connected to the antenna member;
A mounting table that holds the object to be processed and can be heated in the processing container;
A gas supply unit that includes a plurality of process gas supply passages and supplies process gas into the process container from a process gas ejection hole communicating with the process gas supply passage;
An exhaust port for exhausting the inside of 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 holes communicating with the processing gas supply passage is positioned in the circumferential direction of the processing container, and is disposed substantially evenly. A plasma processing apparatus that discharges a processing gas toward a central portion in the processing container. The plasma processing apparatus according to claim 1, wherein the gas supply unit is a nozzle. The plasma processing apparatus according to claim 1, wherein the gas supply unit is a gas supply head. The plasma processing apparatus according to claim 4, wherein the gas supply hole has a dome shape or a tapered shape on the gas ejection hole surface side.

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