JP5943789B2 - Atmospheric pressure plasma deposition system - Google Patents

Description

  The present invention relates to an atmospheric pressure plasma film forming apparatus.

  In the manufacturing process of semiconductor devices, imaging devices, image input line sensors, and the like, a plasma process that performs processes such as thin film formation, etching, sputtering, and surface modification has become an indispensable technology. In this plasma process, low-temperature plasma in which the gas temperature is low and only the electron temperature is high is widely used.

  In the conventional plasma generator for generating the low temperature plasma, a power application electrode for applying pulsed power or high frequency power is disposed in a grounded vacuum vessel, insulated from the vacuum vessel, and the other electrode facing is vacuumed. It arrange | positions electrically connected with a container and fills the arrangement | positioning space of those electrodes with the reactive gas adjusted to the gas pressure of several Pa-100Pa. In this plasma generator, the reaction gas between the electrodes is ionized by a discharge caused by a pulsed electric field or a high-frequency electric field generated between the electrodes, and between the electrodes, negatively charged electrons, positively charged ions, A plasma state (low temperature plasma) is generated in which neutral radicals are mixed with intense motion.

  By the way, in the manufacture of semiconductor devices, the substrate to be deposited tends to increase in size. This is because as the number of substrates processed at a time increases, the number of devices created therefrom increases, and the device unit price decreases. In addition, in imaging devices and solar panels, it can be said that there is a tendency to increase the area in various applications, and the size of a substrate that must be processed at a time is increasing. If it does so, in the technique which adjusts to the gas pressure of several Pa-100Pa mentioned above and produces | generates a plasma, you have to enlarge the vacuum container which accommodates a board | substrate according to a board | substrate size. In this case, the increase in cost due to the enlarging of the apparatus may exceed the cost reduction effect due to the batch processing, resulting in a problem that the manufacturing cost of the device is saturated or increased.

  Therefore, if film formation can be performed using plasma generated at atmospheric pressure, an expensive apparatus equipped with a huge vacuum vessel is not necessary. Under such a background, plasma (hereinafter referred to as atmospheric pressure plasma) excited at a relatively high gas pressure close to atmospheric pressure (specifically, a pressure range of 100 Pa or higher to atmospheric pressure / open ambient pressure or lower) is used. An atmospheric pressure plasma chemical transport deposition method for forming a silicon film has been proposed (see, for example, Patent Documents 1 and 2).

  In Patent Document 1, discharge is generated by arranging a substrate held at a relatively high temperature and a target held at a relatively low temperature in a reaction chamber filled with a reaction gas mainly composed of hydrogen at a pressure of 76 to 1520 Torr in parallel. Thus, a thin film is formed on the substrate.

  Patent Document 2 discloses a first electrode made of a solid dielectric having a plurality of through holes, a second electrode made of solid silicon having a plurality of through holes and a coolant channel, and a first electrode of the second electrode. There is disclosed a plasma film forming apparatus having a structure in which a substrate provided on the opposite side of the substrate is arranged in parallel with each other. Here, while supplying the reaction gas from the first electrode side, a voltage is applied between the first electrode and the second electrode to generate atmospheric pressure plasma. The atmospheric pressure plasma is ejected from the plurality of through holes of the second electrode toward the substrate by the reactive gas flow, and a silicon film is formed on the heated substrate.

International Publication No. 2007/049402 (Fig. 8) JP2011-204995A (FIG. 1)

  As described above, in an industrial field that requires film formation on a large substrate, atmospheric pressure plasma film formation is an effective technique that can reduce the cost of the apparatus. However, in Patent Document 1, a glow plasma generated at a relatively high gas pressure close to atmospheric pressure is used, and the glow plasma has a high gas density. Therefore, in order to maintain a stable plasma, the distance between the target and the substrate is several. It is necessary to make it less than mm. If the target size is 100 mm or more in width or diameter according to the substrate to be enlarged, for example, the reaction gas supplied to the reaction chamber becomes non-uniform in the narrow gap target-substrate. There was a problem.

  Further, in Patent Document 2, since the first electrode and the second electrode are provided with a plurality of through holes, the atmospheric gas generated between the reaction gas and the electrodes is uniform. However, in order to deposit a silicon film using atmospheric pressure plasma ejected from the plurality of through-holes of the second electrode to the substrate side, it is necessary to have a high-speed plasma flow, which requires a large amount of reaction gas. Therefore, there was a problem that it was industrially disadvantageous.

  The present invention has been made in view of the above, and at a relatively high gas pressure close to atmospheric pressure, the reaction gas distribution in the target-substrate disposed in a narrow gap of several mm or less can be made uniform. An object is to obtain an atmospheric pressure plasma film forming apparatus.

In order to achieve the above object, an atmospheric pressure plasma film forming apparatus according to the present invention includes a first electrode connected to a power source and having a solid target, and a second electrode disposed opposite to the first electrode and grounded. irradiated with plasma generated under a pressure of the reaction gas containing less hydrogen than Oite 100Pa atmospheric pressure interelectrode gap to the member to be processed for mounting to a surface of the first electrode side of the second electrode An atmospheric pressure plasma film forming apparatus for forming a film on the member to be processed, wherein a through hole for introducing the reaction gas is provided in a plane of the solid target.

  According to this invention, since the reaction gas is introduced from the through-hole provided in the solid target surface, the distance between the solid target and the substrate is a narrow gap of several millimeters or less, even under a high pressure of 100 Pa or more. The gas distribution / flow can be made uniform, and a stable thin film can be formed.

FIG. 1 is a cross-sectional view schematically showing an example of a schematic configuration of an atmospheric pressure plasma film forming apparatus according to the first embodiment. FIG. 2 is a cross-sectional view schematically showing another configuration example of the power application electrode. FIG. 3 is a perspective view schematically showing an example of a configuration of a solid target having a plurality of through holes. FIG. 4 is a perspective view schematically showing an example of the configuration of a solid target having a plurality of through holes. FIG. 5 is a diagram showing another example of the groove shape when the through holes of FIG. 3 are arranged concentrically. FIG. 6 is a perspective view schematically showing another example of the configuration of the solid target. FIG. 7 is a cross-sectional view schematically showing an example of the configuration of the atmospheric pressure plasma film forming apparatus according to the second embodiment.

  Hereinafter, an atmospheric pressure plasma film forming apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to these embodiments.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view schematically showing an example of a schematic configuration of an atmospheric pressure plasma film forming apparatus according to the first embodiment. In FIG. 1, a reaction vessel 1 serving as a vacuum vessel is formed by forming a conductive member into a bottomed cylindrical shape and is electrically grounded. At the bottom of the reaction vessel 1, an electrically grounded plate-like ground electrode stage 2 is disposed, and a gas discharge port 4 is also provided. A substrate 6, which is a member to be processed, is disposed on the upper surface of the ground electrode stage 2 via a solid dielectric 5. The ground electrode stage 2 incorporates a heater 7 so that the substrate 6 can be heated via the solid dielectric 5. In FIG. 1, the ground electrode stage 2 is parallel to the bottom surface at the end of a column 8 having a predetermined height fixed substantially at the center of the bottom of the reaction vessel 1 (in the illustrated example, at the center of the cylinder). And is supported.

  The ground electrode stage 2 fixed to the support 8 has a configuration capable of operating in the vertical direction, and the distance between the substrate 6 and the solid target 13 via the solid dielectric 5 on the upper surface of the ground electrode stage 2, that is, the plasma 20. It is a structure that can control the interval at which the occurrence occurs.

  A flat holding plate 10 that supports the electrode set 9 is fixed to the open end surface of the reaction vessel 1. The external appearance of the electrode set 9 is a shape constituted by a columnar insertion portion 9a having a predetermined length, and a flange portion 9b provided by protruding in the radial direction of the insertion portion 9a on the drawing end side of the insertion portion 9a. have. The holding plate 10 is made of a conductive member and is electrically grounded. The holding plate 10 is provided with a circular hole 11 slightly larger than the outer diameter of the insertion portion 9a of the electrode set 9. The center of this circular hole 11 coincides with the center of the cylinder (reaction vessel 1) in the illustrated example. The holding plate 10 is used as a cover for closing the open end of the reaction vessel 1.

  The electrode set 9 includes a power application electrode 12, a solid target 13, and a solid dielectric 14. The power application electrode 12 is a cylindrical structure having an insertion portion 12a and a flange portion 12b. The solid target 13 is attached to the end surface of the insertion portion 12 a of the power application electrode 12. The solid dielectric 14 is continuously attached to the outer periphery of the insertion portion 12a excluding the arrangement region of the solid target 13 and the insertion side surface of the flange portion 12b. The power application electrode 12 is provided with a cavity 15 therein and filled with a coolant such as water so that the solid target 13 can be cooled.

  The insertion portion 9a of the electrode set 9 is fitted into the circular hole 11 of the holding plate 10, and is fixed to the holding plate 10 with a fixing member such as a screw (not shown) with good airtightness by a flange portion 9b provided on the drawing end side. As a result, the reaction container 1 becomes a vacuum container that can extract and decompress the so-called air inside, and the electrode set 9 and the holding plate 10 are electrically connected.

  A power source 19 is connected to the power application electrode 12 of the electrode set 9 via a matching box (impedance matching unit) 18. The power source 19 is, for example, a high frequency power source of 13.56 MHz, a high frequency power source of several hundred MHz higher than that, or a pulse power source of several kHz.

  Further, a gas introduction pipe 3 for introducing a reaction gas is attached from the center of the flange portion 12b of the power application electrode 12 to the center of the bottom of the insertion portion 12a, and the upper portion is a gas introduction port 3a. Is connected to the bottom of the insertion portion 12a. A through hole 12c is provided at the attachment position of the gas introduction pipe 3 at the bottom of the insertion portion 12a.

  Furthermore, the reaction gas is applied to the solid target 13 attached to the lower part of the power application electrode 12 so as to be connected to the gas introduction tube 3 and the through hole 12c provided at the bottom of the insertion part 12a of the power application electrode 12. A through hole 21 to be introduced into the plasma forming region is provided. The reaction gas from the gas introduction port 3 a is introduced between the solid target 13 and the substrate 6, which are the formation regions of the plasma 20, from the through holes 12 c and 21 provided in the power application electrode 12 and the solid target 13.

  In the above configuration, when the so-called air in the reaction vessel 1 is discharged from the gas discharge port 4 to obtain a predetermined degree of vacuum, the reaction gas pressure in the reaction vessel 1 is a predetermined value within a range of 100 Pa or more and atmospheric pressure. As shown, the supply amount of the reaction gas introduced through the gas introduction pipe 3, the through hole 12 c of the power application electrode 12 and the through hole 21 of the solid target 13 and the exhaust of the reaction gas discharged from the gas discharge port 4. Adjust the amount. In addition, a refrigerant is put into the cavity 15 to cool the solid target 13 to a certain temperature, and the heater 7 generates heat to heat the substrate 6 to a certain temperature. In this state, when a predetermined high frequency power or pulse power is applied from the power source 19 to the power application electrode 12 through the matching box 18, a discharge occurs between the solid target 13 that is a part of the power application electrode 12 and the ground electrode stage 2. Initiated and plasma 20 is generated. By exposing the substrate 6 to the plasma 20, a predetermined plasma film is formed on the substrate 6.

  For example, hydrogen gas is used as the reaction gas, a silicon plate is used as the solid target 13, the solid target 13 is cooled with a coolant of about 15 ° C., the substrate 6 is heated to about 300 ° C., and hydrogen gas is contained in the reaction vessel 1. When a mixed gas with an inert gas such as helium gas is introduced and the gas pressure in the reaction vessel 1 is adjusted to about 0.9 atm to generate the plasma 20, a silicon film is formed on the substrate 6. The above is an example in which a silicon thin film is formed on the substrate 6, but a predetermined film formation can be performed by using a material in which a hydride is volatile as well as silicon as a target in the same method.

  Next, the shape of the through hole 21 provided in the solid target 13 will be described. The through-hole 21 is formed in a circular shape (cylindrical shape), but it is essential that the plasma generated between the through-hole 21 and the substrate 6 that is the processing target disposed so as not to be disturbed. Then, the examination result of the diameter of the through-hole 21 is shown below.

  In order to stably maintain atmospheric pressure plasma generated at a relatively high gas pressure close to atmospheric pressure, the distance between the solid target 13 and the substrate 6 disposed to face the solid target 13 is set to several mm or less. Plasma is obtained by introducing a mixed gas of hydrogen gas and helium gas from a through hole 21 provided in the center of a solid target 13 made of silicon having a diameter of 100 mm, and adjusting the gas pressure in the reaction vessel 1 to about 0.9 atm. 20 is generated and the diameter of the through hole 21 is examined.

  The power range in which stable discharge can be obtained when the target-substrate distance is 1.0 to 3.0 mm is wide, and glow plasma cannot be generated in a narrow gap where the target-substrate distance is 0.3 mm or less.

  Therefore, when the plasma 20 is generated by setting the target-substrate distance to 2.0 mm and film formation is performed, there is no abnormality in film formation in the circular through hole 21 having a diameter of 3.0 mm, and conventional gas introduction is performed. A silicon film having a better film thickness distribution than the method can be obtained. However, in the circular through hole 21 having a diameter of 5.0 mm, a silicon film thickness distribution presumably due to the edge effect of the through hole 21 at the time of plasma generation is recognized. When the diameter of the through hole 21 is further increased, a region where plasma is not generated is generated.

  In addition, when the plasma is generated by setting the target-substrate distance to 1.0 mm and the film is formed, the circular through hole 21 having a diameter of 3.0 mm has a distribution in the film thickness of the formed silicon. Is recognized. On the other hand, in the circular through-hole 21 having a diameter of 2.0 mm, no abnormality is observed in the formed silicon film.

  From the above examination, in order to form a uniform film, it is necessary to make the diameter of the through hole 21 not more than twice the distance between the target and the substrate. However, it has been found through experiments that a structure in which a mechanism for moving the substrate 6 while maintaining the target-substrate distance is added to the atmospheric pressure plasma film forming apparatus can achieve film uniformity even in larger through holes.

  As in the first embodiment, the through-hole 21 for supplying the reaction gas is provided in the central portion of the solid target 13, so that the reaction gas is introduced from the side wall of the conventional reaction vessel 1 between the target and the substrate. The reaction gas distribution is improved and a good film thickness distribution is obtained.

  FIG. 2 is a cross-sectional view schematically showing another configuration example of the power application electrode. In the power application electrode 12 of FIG. 1, the through-hole 21 provided in the solid target 13 has a single-hole structure with only a central portion. However, as shown in FIG. 2, a plurality of through holes 21 may be provided in the solid target 13. In this case, the size (diameter) of each through-hole 21 should just be 2 times or less of the target-substrate distance which is the range which can produce | generate plasma stably as mentioned above. As a result, the film thickness distribution can be made more uniform, and a good film thickness distribution can be obtained even for a large-diameter solid target.

  3 and 4 are perspective views schematically showing an example of the configuration of a solid target having a plurality of through holes. FIG. 3 is a perspective view showing an example of a solid target in which a plurality of through holes are concentrically arranged, and FIG. 4 is a perspective view showing an example of a solid target in which a plurality of through holes are arranged in a cross shape. In each figure, (a) shows a perspective view on the lower surface side (side facing the substrate), and (b) shows a perspective view on the upper surface side (side in contact with the power application electrode).

  Even when a plurality of through holes 21 are concentrically provided in the solid target 13 as shown in FIG. 3 or when a plurality of through holes 21 are provided in a cross shape in the solid target 13 as shown in FIG. It is effective to obtain or obtain a good film thickness distribution on the large-diameter solid target 13.

  In the case where the plurality of through holes 21 are provided, a structure in which the gas introduction pipes 3 for the reaction gas are provided in the respective through holes 21 is possible, but the structure of the power application electrode 12 is complicated. Therefore, in the structure shown in FIGS. 3 and 4, the gas introduction pipe 3 is provided only for one system to the center of the solid target 13, and the plurality of through holes 21 are formed on the surface where the solid target 13 is in contact with the power application electrode 12. A groove 22 for distributing the reaction gas is provided. The groove 22 only needs to be larger than the diameter of the through hole 21 and can have an arbitrary depth. For example, the width of the groove 22 can be 2.0 mm and the depth can be 1.0 mm. Note that the number and arrangement of the through holes 21 and the shape of the path of the groove 22 for distributing the reaction gas in the case of forming a plurality of through holes 21 are not limited to this shape.

  Further, the area of the path of the groove 22 that distributes the reaction gas formed on the surface where the solid target 13 is in contact with the power application electrode 12 is such that the solid target 13 is made of a coolant such as water filled in the cavity 15 inside the power application electrode 12. It is desirable to make it as large as possible as long as the effect of cooling is not impaired.

  FIG. 5 is a diagram showing another example of the groove shape when the through holes of FIG. 3 are arranged concentrically. This figure shows a perspective view of the upper surface side (side in contact with the power application electrode). In FIG. 3, the groove 22 connecting the plurality of concentric through holes 21 includes a circular groove 22 a connecting between the through holes 21 arranged on the outermost periphery and a through hole 21 arranged on the inner side thereof. And a cross-shaped groove 22b to be connected. On the other hand, the groove 22 of FIG. 5 has a structure in which four Y-shaped grooves 22c rotated 90 degrees from the central through hole 21 are arranged. As shown in FIGS. 3 and 5, the groove shape can be arbitrary.

  Moreover, although the case where the groove | channel 22 which connects between the several through-holes 21 was formed in the solid target 13 in the above-mentioned description was shown, it is not limited to this. FIG. 6 is a perspective view schematically showing another example of the configuration of the solid target. As shown in FIG. 6, the structure further includes a spacer 25 in which a guide 25 a for distributing the reaction gas to each through hole 21 is formed between the solid target 13 and the power application electrode 12. . The spacer 25 has a structure in which a portion to be a flow path (guide 25a) is extracted. As the material of the spacer 25, a material having good conductivity and thermal conductivity, such as copper or aluminum, can be used. Further, in this case, since the solid target 13 does not need to be grooved on the surface on the power application electrode 12 side, the manufacturing cost of the solid target 13 can be reduced as compared with the case of FIGS. .

  In the first embodiment, the reaction gas is introduced into the space between the solid target 13 and the substrate 6 from one or more through holes 21 provided in the surface of the solid target 13 attached to the power application electrode 12. As a result, in the plasma forming region between the ground electrode stage 2 and the ground electrode stage 2 which is disposed opposite to the solid target 13 and holds the substrate 6, the distance between the solid target 13 and the substrate 6 is several mm or less. Therefore, even under a relatively high pressure of 100 Pa or more and atmospheric pressure or less, the gas distribution and flow are uniform, and the resulting film can be improved in uniformity. Moreover, even when the solid target 13 is enlarged by providing a plurality of through holes 21, the same effect can be obtained.

  Furthermore, the diameter of the through-hole 21 provided in the solid target 13 is set to be not more than twice the distance between the solid target 13 and the substrate 6, thereby affecting the plasma generation between the solid target 13 and the substrate 6. There is also an effect that a good film can be obtained.

Embodiment 2. FIG.
In the first embodiment, the atmospheric pressure plasma film forming apparatus provided with a reaction vessel serving as a vacuum vessel has been described. However, as an atmospheric pressure plasma film forming apparatus, an inert gas was supplied as a curtain gas around the plasma discharge area with a larger supply amount than the reactive gas, and the surrounding atmosphere was covered with a purge gas and blown toward the substrate. By sucking and discharging the curtain gas and the purge gas from the exhaust duct, an environment equivalent to a reaction vessel serving as a vacuum vessel can be formed in the plasma generation region. In the second embodiment, an atmospheric pressure plasma film forming apparatus that does not have this reaction vessel will be described.

  FIG. 7 is a cross-sectional view schematically showing an example of the configuration of the atmospheric pressure plasma film forming apparatus according to the second embodiment. In FIG. 7, the left-right direction of the paper surface is the X-axis direction, the direction in the paper surface perpendicular to the X-axis is the Z-axis (height direction), and the direction perpendicular to both the X-axis and the Z-axis (perpendicular to the paper surface) Is the Y axis.

  The atmospheric pressure plasma film forming apparatus includes a plasma processing head 101 and a stage 120 that holds a substrate 119 that is a member to be processed.

  The plasma processing head 101 includes an input-side high-frequency electrode 111 on which a cooling mechanism 110 that can apply high-frequency power is mounted, and a flow path component 113 that is disposed on the outer peripheral portion of the plasma processing head 101 via an insulator 112. In addition, a flat solid target 114 is provided on the surface of the input-side high-frequency electrode 111 facing the surface to be processed of the substrate 119. Both the input-side high-frequency electrode 111 and the flow path component 113 have a rectangular shape in plan view, and a rectangular solid target 114 is disposed on the bottom surface of the rectangular-shaped input-side high-frequency electrode 111. An insulator 112 for preventing arc generation is disposed in a region other than the position where the solid target 114 is installed on the input side high-frequency electrode 111, and a flow path component member 113 is provided on a side surface perpendicular to the Z-axis direction. Note that the input-side high-frequency electrode 111 and the flow path component 113 may be other shapes such as a circular shape instead of a rectangular shape in plan view.

  The flow path component 113 is provided with a reaction gas flow path 116, an exhaust flow path 118, and a curtain gas flow path 117. The reactive gas flow path 116 is disposed at the center in the XY plane of the input side high-frequency electrode 111 and has a cylindrical shape extending in the Z direction. A reactive gas supply unit 131 is connected to the positive side of the reactive gas channel 116 in the Z-axis direction via a reactive gas supply channel 141. The reaction gas supply unit 131 supplies a reaction gas mainly composed of hydrogen to the reaction gas channel 116. As a result, the reaction gas passes through the reaction gas flow path 116 from the positive direction of the Z axis toward the negative direction, and is supplied to the space between the substrate 119 and the solid target 114 from the end in the negative direction of the Z axis. . The reaction gas is a mixed gas containing hydrogen as described above, and examples thereof include a mixed gas of hydrogen and a rare gas such as helium or argon. Although it is sufficient that hydrogen is contained even in a trace amount in the mixed gas, the hydrogen concentration is 1 vol. From the viewpoint of a practical film formation rate (0.1 nm / s or more). % Or more is desirable. Further, a trace amount of a dopant gas such as oxygen, nitrogen, hydrocarbon, diborane, or phosphine can be added as a dopant.

  The end of the reactive gas flow path 116 on the negative side in the Z direction is the position where the solid target 114 is disposed. Therefore, a through hole 121 is provided at a position overlapping the reactive gas flow path 116 near the center of the solid target 114. Since the configuration of the solid target 114 is the same as that described in the first embodiment, a detailed description thereof will be omitted.

  The exhaust passage 118 and the curtain gas passage 117 are provided to extend in the Z-axis direction so as to surround the input-side high-frequency electrode 111. An exhaust passage 118 is provided on the side close to the input side high-frequency electrode 111.

  The curtain gas flow channel 117 is disposed outside the reaction gas flow channel 116, and a curtain gas supply unit 132 is connected to the positive side of the Z axis via a curtain gas supply channel 142. The curtain gas supply unit 132 supplies a curtain gas such as an inert gas to the curtain gas channel 117. As a result, the curtain gas passes through the curtain gas flow path 117 from the Z-axis positive direction toward the negative direction, and is sprayed from the end in the Z-axis negative direction toward the stage 120 (substrate 119). Is sucked from the exhaust flow path 118 and the rest is released into the external atmosphere. This curtain gas prevents intrusion of air and contamination from the space outside the curtain gas and outflow of the reaction gas from the space inside the curtain gas to the outside. The curtain gas is an inert gas as described above, and examples thereof include rare gases such as helium and argon.

  The exhaust flow path 118 is disposed outside the reaction gas flow path 116 and inside the curtain gas flow path 117 so as to surround the plasma generation region (plasma generation space) from the outside, and an exhaust pump 133 is disposed on the Z axis positive direction side. The exhaust gas exhaust path 143 is connected. The exhaust pump 133 includes a gas decomposed by plasma existing in a space between the flow path component 113 and the stage 120, a reaction product gas generated by reacting with the solid target 114 and the substrate 119, and a curtain gas (hereinafter referred to as a curtain gas). These gases may be collectively referred to as unreacted gas or the like) through an exhaust passage 118 to an exhaust gas processing unit (not shown). Thereby, unreacted gas and the like pass from the Z-axis negative direction toward the positive direction.

  The flow rate of the reaction gas, the flow rate of the curtain gas, and the flow rate of the exhaust gas are set so as to satisfy the relationship of the flow rate of the reaction gas <the flow rate of the exhaust gas <the flow rate of the curtain gas. By setting in this way, the outflow of the reaction gas to the external atmosphere can be prevented to ppm or less of the reaction gas, and the inflow amount of air from the external atmosphere to the exhaust flow path 118 is reduced to the unreacted gas or the like. The exhaust gas can be suppressed to ppm or less.

  The stage 120 is disposed with a predetermined distance from the plasma processing head 101, and holds the substrate 119 so that the surface to be processed of the substrate 119 is substantially parallel to the plasma processing head 101. The stage 120 is grounded and also functions as a ground-side high-frequency electrode. A heating mechanism may be provided inside the stage 120. The stage 120 is provided with a moving unit 138 that moves the stage 120 in the XY plane, and a control unit 140 that controls the moving unit 138.

  The input side high-frequency electrode 111 and the stage 120 that is the ground-side high-frequency electrode constitute a high-frequency electrode. As a material of the high frequency electrode, for example, copper, aluminum, stainless steel, brass or the like can be used. The input-side high-frequency electrode 111 is connected to a plasma-generating high-frequency power source 115, and the ground-side high-frequency electrode (stage 120) is grounded. When high-frequency power is supplied from the high-frequency power source 115 to the high-frequency electrodes (the input-side high-frequency electrode 111 and the stage 120), a gap region existing between the solid target 114 and the substrate 119 becomes a plasma generation region where plasma is generated.

  The plasma processing head 101 and the stage 120 are configured to be relatively movable in the XY plane. In the example of FIG. 7, the plasma processing head 101 is fixed and the stage 120 is configured to move by the moving unit 138. However, the stage 120 is fixed and the plasma processing head 101 is configured to move. Alternatively, the plasma processing head 101 and the stage 120 can be moved together.

  Next, a procedure for forming a semiconductor film (silicon film) using the atmospheric pressure plasma film forming apparatus having such a configuration will be described. First, the substrate 119 is placed on the stage 120, for example, with the left end of the substrate 119 in FIG. 7 positioned on the right side of the solid target 114. Also, curtain gas is sprayed from the curtain gas supply unit 132 to the stage 120 via the curtain gas channel 117, and the reaction gas from the reaction gas supply unit 131 is connected to the input high-frequency electrode 111 and the stage via the reaction gas channel 116. It is supplied to the space between 120. At this time, the reactive gas is supplied from the through hole 121 provided in the solid target 114 to the stage 120 side. Further, high-frequency power is applied from the high-frequency power source 115 to the high-frequency electrodes (the input-side high-frequency electrode 111 and the stage 120), and the reaction gas is turned into plasma in the space between the solid target 114 and the stage 120. At this time, unreacted gas including a part of the curtain gas is exhausted by the exhaust pump 133 through the exhaust flow path 118, and the remainder of the curtain gas is released into the external atmosphere. Further, the cooling mechanism 110 for the input-side high-frequency electrode 111 and the heating mechanism for the stage 120 (ground-side high-frequency electrode) are operated to control the temperature so as to reach a predetermined temperature.

  In this state, the stage 120 is moved in the moving direction (for example, the negative direction of the X axis) by the moving unit 138, and the substrate 119 enters the plasma generation region. Here, the stage 120 may move continuously, or may move by repeatedly moving and stopping in steps.

  As the stage 120 moves in the negative X-axis direction, the surface to be processed at the left end of the substrate 119 enters the lower part of the solid target 114. Under the solid target 114, etching of the solid target material is performed by generating and volatilizing a hydride of the solid target material on the surface of the solid target 114 and the substrate 119 by a plasma reaction gas (hydrogen atom, hydrogen radical, etc.). In addition, the hydride of the reactive target material that has volatilized on the surfaces of the solid target 114 and the substrate 119 is re-decomposed in the plasma and is deposited on the surfaces of the solid target 114 and the substrate 119. Both processes occur simultaneously.

When Si is used as the solid target 114, the solid target material is etched by the reaction shown in the following formula (1), and a semiconductor film is formed by the reaction shown in the following formula (2).
Si + xH → SiH _x (x = 0, 1, 2,...) (1)
SiH _x → Si + xH (x = 0, 1, 2,...) (2)

  As for the etching rate and deposition rate of the solid target material, the etching rate is higher than the deposition rate on the surface of the solid target 114 on the low temperature side. On the other hand, on the surface of the substrate 119 on the high temperature side, the film formation rate is higher than the etching rate. Accordingly, by appropriately increasing the temperature difference between the two, the difference in the etching and film formation speed increases, and relatively high-speed mass transfer from the low-temperature side solid target 114 to the high-temperature side substrate 119 occurs. A semiconductor film is formed over the substrate 119. Such mass transfer that is not performed under reduced pressure in a sealed space is called an atmospheric pressure plasma chemical transport method.

  In the configuration in which the reaction gas is introduced from the periphery of the solid target 114, the reaction gas is formed not to be between the solid target 114 and the substrate 119, which is a plasma generation region, but to surround the input high-frequency electrode 111. A flow is generated in the exhaust passage 118. Therefore, as in the first embodiment, the method of directly introducing the reactive gas into the plasma generation region from the through hole 121 provided in the solid target 114 is effective for forming a uniform film.

  The temperature required for film formation differs depending on the substance, but in the case of silicon, for example, film formation is possible if the temperature difference between the input-side high-frequency electrode 111 and the stage 120 is 100 ° C. or more. However, if the temperature on the low temperature side is, for example, 15 ° C. and the temperature on the high temperature side is, for example, 300 ° C., the film formation rate is further increased as compared to when the temperature difference is 100 ° C. .

  The film formation process as described above is executed as the stage 120 moves in the negative X-axis direction, and a semiconductor film is formed on the entire surface to be processed of the substrate 119.

  According to the second embodiment, the atmospheric pressure plasma in which the reaction gas is introduced without using a reaction vessel serving as a vacuum vessel and the curtain gas channel 117 and the exhaust channel 118 are formed around the region where the atmospheric pressure plasma is generated. Also in the film forming apparatus, similarly to the first embodiment, the gas distribution and flow are uniform by introducing a mixed gas of an inert gas such as hydrogen gas and helium gas from the through-hole 121 provided in the solid target 114. The uniformity of the resulting film can be improved.

  Although a method of forming a silicon film by using a silicon plate for the solid target 114 has been described, even if a material in which hydride is volatile, for example, C, SiC, Ge is used as a solid target, Similar effects can be obtained.

  As described above, the atmospheric pressure plasma film forming apparatus according to the present invention is useful when a thin film is formed on a large substrate, and is particularly suitable for manufacturing an imaging device, a solar panel, and the like.

  DESCRIPTION OF SYMBOLS 1 Reaction container, 2 Ground electrode stage, 3 Gas inlet pipe, 3a Gas inlet, 4 Gas outlet, 5 Solid dielectric, 6,119 Substrate, 7 Heater, 8 Prop, 9 Electrode set, 9a Insertion part, 9b Flange Part, 10 holding plate, 11 circular hole, 12 power application electrode, 12a insertion part, 12c, 21, 121 through hole, 12b flange part, 13,114 solid target, 14 solid dielectric, 15 cavity, 18 matching box, 19 Power source, 20 plasma, 22, 22a-22c groove, 25 spacer, 25a guide, 101 plasma processing head, 110 cooling mechanism, 111 input side high frequency electrode, 112 insulator, 113 flow path component, 115 high frequency power source, 116 reaction gas Flow path, 117 curtain gas flow path, 118 exhaust flow path, 120 stage, 31 reaction gas supply unit, 132 curtain gas supply unit, 133 an exhaust pump, 138 moving means 140 control unit, 141 a reaction gas supply passage, 142 curtain gas supply path, 143 an exhaust gas discharge path.

Claims (6)

Power source is connected, a first electrode having a solid target, the reaction gas containing a second electrode and, the inter-electrode-atmospheric hydrogen over Oite 100Pa in a gap that is arranged to face the first electrode ground An atmospheric pressure plasma film forming apparatus for irradiating a member to be processed placed on a surface of the second electrode on the first electrode side with plasma generated under pressure to form a film on the member to be processed. ,
An atmospheric pressure plasma film forming apparatus comprising a through hole for introducing the reaction gas in a plane of the solid target. A first electrode for holding a member to be processed;
A second electrode disposed opposite to the first electrode, a reaction gas flow path for supplying a reaction gas to a region between the first electrode and the second electrode, and disposed outside the reaction gas flow path A curtain gas passage for injecting curtain gas toward the first electrode, and a gas containing the reaction gas and the curtain gas disposed outside the reaction gas passage and inside the curtain gas passage. A plasma processing head including a flow path component having an exhaust flow path for exhausting;
A RF power applying means for applying high frequency power, a plasma of the reaction gas between the first electrode and the second electrode between the first electrode and the second electrode,
A solid target disposed inside the region surrounded by the exhaust flow path on the surface of the second electrode facing the first electrode, and reacting with the plasmad reaction gas;
Moving means for relatively moving the first electrode and the second electrode;
With
The reaction gas flow path is provided in the vicinity of the center of the region surrounded by the exhaust flow path of the flow path component so as to penetrate in the thickness direction of the flow path component.
The atmospheric pressure plasma deposition apparatus, wherein the solid target includes a through-hole connected to the reaction gas channel in a plane of the solid target.   The atmospheric pressure plasma deposition apparatus according to claim 1, wherein a plurality of the through holes are provided in the solid target.   The atmospheric pressure plasma film forming apparatus according to claim 3, wherein a groove connecting the plurality of through holes is formed on a surface of the solid target on a side to which the reaction gas is supplied.   The atmospheric pressure plasma deposition according to claim 3, further comprising a spacer member in which a guide connecting the plurality of through holes is formed on a surface of the solid target to which the reaction gas is supplied. apparatus.   3. The atmospheric pressure plasma deposition apparatus according to claim 1, wherein a diameter of the through-hole has a size equal to or smaller than twice a distance between the solid target and the member to be processed.

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