JP2020198390A - Deposition method and deposition device - Google Patents

Abstract

To provide a technology capable of generating plasma discharge stably.SOLUTION: A deposition method according to one aspect of the present disclosure has a step of placing multiple boards, including at least a first dummy board and a second board different from the first board, on a turntable provided in a processing chamber, and capable of placing a board on the top face along the hoop direction, and a step of modifying the film deposited on the board by using radical formed by a plasma source in a plasma treatment area within the processing chamber, while rotating the turntable. In the modification step, plasma is ignited when the second board is located in the plasma treatment area.SELECTED DRAWING: Figure 11

Description

The present disclosure relates to a film forming method and a film forming apparatus.

Five or six wafers are placed on the rotary table along the circumferential direction, and the raw material gas supply unit and the gas are turned into plasma so as to face the trajectory of the wafer that moves (revolves) due to the rotation of the rotary table. A film forming apparatus in which an antenna for this purpose is arranged is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-45903

The present disclosure provides a technique capable of stably generating a plasma discharge.

The film forming method according to one aspect of the present disclosure is different from at least the first substrate for dummy and the first substrate on a rotary table provided in the processing chamber and on which the substrate can be placed on the upper surface along the circumferential direction. A film was formed on the substrate by using a step of placing a plurality of substrates including a second substrate and a radical generated by a plasma source in a plasma processing region in the processing chamber while rotating the rotary table. It has a step of modifying the film, and in the step of modifying, the plasma is ignited when the second substrate is located in the plasma processing region.

According to the present disclosure, plasma discharge can be stably generated.

Sectional drawing which shows the structural example of the film forming apparatus of one Embodiment Top view of the film forming apparatus of FIG. A cross-sectional view taken along the concentric circles of the rotary table of the film forming apparatus of FIG. Cross-sectional view of the plasma source provided in the film forming apparatus of FIG. An exploded perspective view of a plasma source provided in the film forming apparatus of FIG. A perspective view of an example of a housing provided in the plasma source of FIG. Another sectional view of the plasma source provided in the film forming apparatus of FIG. A perspective view showing an enlarged view of a plasma processing gas nozzle provided in the plasma processing area. Top view of an example of the plasma source of FIG. Perspective view showing a part of Faraday shield provided in the plasma source Explanatory drawing of relationship between plasma source and position of wafer at the time of plasma ignition of Example 1. The figure which shows the evaluation result of the ignitability of plasma in Example 1. Explanatory drawing of the relationship between the plasma source and the position of the wafer at the time of plasma ignition of Comparative Example 1. The figure which shows the evaluation result of the ignitability of plasma in the comparative example 1.

Hereinafter, exemplary embodiments not disclosed will be described with reference to the accompanying drawings. In all the attached drawings, the same or corresponding members or parts are designated by the same or corresponding reference numerals, and duplicate description is omitted.

(Film formation equipment)
The film forming apparatus of one embodiment will be described. FIG. 1 is a cross-sectional view showing a configuration example of the film forming apparatus of one embodiment. FIG. 2 is a plan view of the film forming apparatus of FIG. In FIG. 2, the top plate 11 is not shown for convenience of explanation.

As shown in FIG. 1, the film forming apparatus is provided in a vacuum vessel 1 having a substantially circular planar shape and in the vacuum vessel 1, having a rotation center at the center of the vacuum vessel 1 and revolving the wafer W. The rotary table 2 and the like are provided.

The vacuum vessel 1 is a processing chamber for accommodating the wafer W, performing a film forming process on the surface of the wafer W, and depositing a thin film. The vacuum container 1 includes a top plate 11 provided at a position facing a recess 24 described later in the rotary table 2, and a container body 12. A sealing member 13 provided in an annular shape is provided on the peripheral edge of the upper surface of the container body 12. The top plate 11 is configured to be removable from the container body 12. The diameter dimension (inner diameter dimension) of the vacuum vessel 1 in a plan view is not limited, but may be, for example, about 1100 mm.

A separation gas supply pipe 51 for supplying separation gas is connected to the central portion on the upper surface side of the vacuum vessel 1 in order to prevent different processing gases from being mixed with each other in the central region C in the vacuum vessel 1. There is.

The rotary table 2 is fixed to the core portion 21 having a substantially cylindrical shape at the central portion, and is connected to the lower surface of the core portion 21 and extends in the vertical direction with respect to the rotary shaft 22 around the vertical axis, as shown in FIG. In the example shown, the drive unit 23 is rotatably configured to rotate clockwise. The diameter of the rotary table 2 is not limited, but may be, for example, about 1000 mm.

The drive unit 23 is provided with an encoder 25 that detects the rotation angle of the rotation shaft 22. In one embodiment, the rotation angle of the rotary shaft 22 detected by the encoder 25 is transmitted to the control unit 120, and the position of the wafer W placed in each recess 24 on the rotary table 2 by the control unit 120 is determined. Used to identify.

The rotating shaft 22 and the driving unit 23 are housed in the case body 20. In the case body 20, the flange portion on the upper surface side is airtightly attached to the lower surface of the bottom surface portion 14 of the vacuum container 1. A purge gas supply pipe 72 for supplying Ar gas or the like as a purge gas (separation gas) is connected to the lower region of the rotary table 2 to the case body 20.

The outer peripheral side of the core portion 21 of the bottom surface portion 14 of the vacuum vessel 1 is formed in an annular shape so as to approach the rotary table 2 from the lower side to form a protruding portion 12a.

On the surface of the rotary table 2, a circular recess 24 on which a wafer W having a diameter of, for example, 300 mm can be placed is formed. The recesses 24 are provided at a plurality of locations, for example, six locations along the rotation direction of the rotary table 2 (the direction indicated by the arrow A in FIG. 2). The recess 24 has an inner diameter slightly larger than the diameter of the wafer W, specifically, about 1 mm to 4 mm. The depth of the recess 24 is configured to be substantially equal to or greater than the thickness of the wafer W. Therefore, when the wafer W is housed in the recess 24, the surface of the wafer W and the surface of the flat region on which the wafer W of the rotary table 2 is not placed are at the same height, or the surface of the wafer W is the rotary table 2. It will be lower than the surface of. Further, a through hole (not shown) through which, for example, three elevating pins, which will be described later, are formed is formed on the bottom surface of the recess 24 for pushing up and lowering the wafer W from the lower side.

As shown in FIG. 2, the first processing region P1, the second processing region P2, and the third processing region P3 are provided apart from each other along the rotation direction of the rotary table 2. At a position of the rotary table 2 facing the passing region of the recess 24, for example, a plurality of quartz nozzles 31, 32, 33, 34, 35, 41, 42 are located in the circumferential direction of the vacuum vessel 1. They are arranged radially at intervals.

Each of the gas nozzles 31 to 35, 41, and 42 is arranged between the rotary table 2 and the top plate 11. Each of the gas nozzles 31 to 34, 41, and 42 is attached so as to extend horizontally from the outer peripheral wall of the vacuum vessel 1, for example, toward the central region C and facing the rotary table 2. On the other hand, the gas nozzle 35 extends from the outer peripheral wall of the vacuum vessel 1 toward the central region C, then bends and linearly counterclockwise along the central region C (direction opposite to the rotation direction of the rotary table 2). Extends to.

In the example shown in FIG. 2, the plasma processing gas nozzles 33, 34, 35, the separation gas nozzle 41, the first processing gas nozzle 31, the separation gas nozzle 42, and the second are clockwise from the transport port 15 described later (the rotation direction of the rotary table 2). The processing gas nozzles 32 of 2 are arranged in this order. The gas supplied by the second processing gas nozzle 32 is often the same quality as the gas supplied by the plasma processing gas nozzles 33 to 35, but the gas is supplied by the plasma processing gas nozzles 33 to 35. Is not always provided when is sufficient.

Further, the plasma processing gas nozzles 33 to 35 may be replaced by one plasma processing gas nozzle. In this case, for example, similarly to the second processing gas nozzle 32, a plasma processing gas nozzle extending from the outer peripheral wall of the vacuum vessel 1 toward the central region C may be provided.

The first processing gas nozzle 31 forms the first processing gas supply unit. Further, the second processing gas nozzle 32 forms a second processing gas supply unit. Further, the plasma processing gas nozzles 33 to 35 each form a plasma processing gas supply unit. Further, the separated gas nozzles 41 and 42 each form a separated gas supply unit.

The gas nozzles 31 to 35, 41, and 42 are connected to their respective gas supply sources (not shown) via a flow rate adjusting valve.

On the lower surface side (the side facing the rotary table 2) of the gas nozzles 31 to 35, 41, 42, gas discharge holes 36 for discharging each of the above-mentioned gases are provided at a plurality of locations along the radial direction of the rotary table 2, for example. It is formed at equal intervals. The lower end edges of the gas nozzles 31 to 35, 41, and 42 are arranged so that the distance between the lower end edge and the upper surface of the rotary table 2 is, for example, about 1 to 5 mm.

The lower region of the first processing gas nozzle 31 is the first processing region P1 for adsorbing the raw material gas on the wafer W, and the lower region of the second processing gas nozzle 32 oxidizes the raw material gas to form an oxide. This is the second processing region P2 that supplies the oxidizable gas that can be generated to the wafer W. Further, the lower region of the plasma processing gas nozzles 33 to 35 becomes a third processing region P3 for reforming the film on the wafer W.

The first processing gas nozzle 31 supplies a silicon-containing gas when forming a silicon oxide film or a silicon nitride film, and a metal-containing gas when forming a metal oxide film or a metal nitride film. As described above, the first processing gas nozzle 31 is a nozzle that supplies the raw material gas (precursor) containing the raw material that is the main component of the thin film. Therefore, the first processing gas nozzle 31 is also referred to as a raw material gas nozzle 31. Further, since the first processing region P1 is a region for adsorbing the raw material gas on the wafer W, it is also referred to as a raw material gas adsorption region P1.

Similarly, the second processing gas nozzle 32 also refers to the oxide gas nozzle 32 because it supplies an oxidizing gas such as oxygen, ozone, water, and hydrogen peroxide to the wafer W when the oxide film is formed. Further, since the second processing region P2 is a region in which the oxidation gas is supplied to the wafer W on which the raw material gas is adsorbed in the first processing region P1 to oxidize the raw material gas adsorbed on the wafer W, it is also called the oxidation region P2. Refer to. In the oxidation region P2, the molecular layer of the oxide film is deposited on the wafer W.

Similarly, the third treated region P3 is also referred to as a plasma treated region P3 because it is a region in which the molecular layer of the oxide film formed in the second treated region P2 is plasma-treated to modify the oxide film. In one embodiment, since the oxide film is formed, the plasma processing gas supplied from the plasma processing gas nozzles 33 to 35 is, for example, a gas containing oxygen. However, when the nitride film is formed, the plasma processing gas supplied from the plasma processing gas nozzles 33 to 35 is, for example, a gas containing nitrogen.

The separation gas nozzles 41 and 42 are provided to form a separation region D that separates the first processing region P1, the second processing region P2, and the third processing region P3 and the first processing region P1. The separation gas supplied from the separation gas nozzles 41 and 42 is an inert gas such as nitrogen or a rare gas such as helium or argon. Since the separation gas also functions as a purge gas, the separation gas may be referred to as a purge gas, and the separation gas nozzles 41 and 42 are also referred to as purge gas nozzles 41 and 42. A separation region D is not provided between the second processing region P2 and the third processing region P3. This is because the oxygen gas supplied in the second processing region P2 and the mixed gas supplied in the third processing region P3 commonly contain oxygen atoms in the mixed gas, and both of them contain oxygen atoms. Functions as an oxidant. Therefore, it is not necessary to separate the second processing region P2 and the third processing region P3 by using a separation gas.

Since the plasma processing gas nozzles 33 to 35 have a structure of supplying gas to different regions on the rotary table 2, the flow rate ratio of each component of the mixed gas is different for each region, and the reforming treatment is performed as a whole. It may be supplied so that it is performed uniformly in.

FIG. 3 is a cross-sectional view taken along the concentric circles of the rotary table 2 of the film forming apparatus of FIG. 1, and is a cross-sectional view from the separation region D to the separation region D via the first processing region P1.

The top plate 11 of the vacuum container 1 in the separation region D is provided with a substantially fan-shaped convex portion 4. The convex portion 4 is attached to the back surface of the top plate 11. Inside the vacuum vessel 1, a flat low ceiling surface (hereinafter referred to as "first ceiling surface 44"), which is the lower surface of the convex portion 4, and both sides of the first ceiling surface 44 in the circumferential direction are located. A ceiling surface higher than the first ceiling surface 44 (hereinafter referred to as “second ceiling surface 45”) is formed.

As shown in FIG. 2, the convex portion 4 forming the first ceiling surface 44 has a fan-shaped planar shape whose top is cut in an arc shape. A groove 43 is formed in the convex portion 4 so as to extend in the radial direction at the center in the circumferential direction. Separation gas nozzles 41 and 42 are housed in the groove 43. The peripheral edge of the convex portion 4 (the portion on the outer edge side of the vacuum vessel 1) faces the outer end surface of the rotary table 2 and is slightly relative to the container body 12 in order to prevent mixing of the processing gases. It is bent in an L shape so as to be separated.

On the upper side of the first processing gas nozzle 31, the separation gas passes through the top plate 11 side of the vacuum vessel 1 in order to allow the first processing gas to flow along the wafer W and avoiding the vicinity of the wafer W. A nozzle cover 230 is provided so that the gas can flow. As shown in FIG. 3, the nozzle cover 230 includes a cover body 231 and a straightening vane 232. The cover body 231 has a substantially box shape with an opening on the lower surface side for accommodating the first processing gas nozzle 31. The straightening vane 232 is a plate-like body connected to the upstream side and the downstream side in the rotation direction of the rotary table 2 at the lower surface side opening end of the cover body 231. The side wall surface of the cover body 231 on the rotation center side of the rotary table 2 extends toward the rotary table 2 so as to face the tip end portion of the first processing gas nozzle 31. Further, the side wall surface of the cover body 231 on the outer edge side of the rotary table 2 is cut out so as not to interfere with the first processing gas nozzle 31. The nozzle cover 230 is not essential and may be provided as needed.

As shown in FIG. 2, a plasma source 80 is provided on the upper side of the plasma processing gas nozzles 33 to 35 in order to convert the plasma processing gas discharged into the vacuum vessel 1 into plasma. The plasma source 80 uses an antenna 83 to generate inductively coupled plasma.

FIG. 4 is a cross-sectional view of the plasma source 80 provided in the film forming apparatus of FIG. FIG. 5 is an exploded perspective view of the plasma source 80 provided in the film forming apparatus of FIG. FIG. 6 is a perspective view of an example of the housing 90 provided in the plasma source 80 of FIG.

The plasma source 80 is configured by winding an antenna 83 formed of a metal wire or the like in a coil shape, for example, three times around a vertical axis. Further, the plasma source 80 is arranged so as to surround the strip-shaped region extending in the radial direction of the rotary table 2 in a plan view and to straddle the diameter portion of the wafer W on the rotary table 2.

The antenna 83 is connected to a high frequency power supply 85 having a frequency of, for example, 13.56 MHz and an output power of, for example, 5000 W via a matching unit 84. The antenna 83 is provided so as to be airtightly partitioned from the internal region of the vacuum container 1. In addition, in FIGS. 4 and 5, a connection electrode 86 for electrically connecting the antenna 83, the matching unit 84, and the high-frequency power supply 85 is provided.

The antenna 83 may be provided with a structure that can be bent up and down, a vertical movement mechanism that can automatically bend the antenna 83 up and down, and a mechanism that can move the center side of the rotary table 2 up and down, if necessary. .. In FIG. 4, those configurations are omitted.

As shown in FIGS. 4 and 5, the top plate 11 on the upper side of the plasma processing gas nozzles 33 to 35 is formed with an opening 11a that opens substantially in a fan shape in a plan view.

As shown in FIG. 4, the opening 11a has an annular member 82 that is airtightly provided in the opening 11a along the opening edge of the opening 11a. The housing 90, which will be described later, is airtightly provided on the inner peripheral surface side of the annular member 82. That is, the annular member 82 is airtightly provided with the outer peripheral side in contact with the inner peripheral surface 11b of the opening 11a of the top plate 11 and the inner peripheral side in contact with the flange portion 90a of the housing 90 described later. Then, in order to position the antenna 83 below the top plate 11, a housing 90 made of a derivative such as quartz is provided in the opening 11a via the annular member 82. The bottom surface of the housing 90 constitutes the ceiling surface 46 of the plasma processing region P3.

As shown in FIG. 6, in the housing 90, the upper peripheral edge extends horizontally in a flange shape in the circumferential direction to form a flange portion 90a, and in a plan view, the central portion is the lower vacuum container. It is formed so as to be recessed toward the internal region of 1.

The housing 90 is arranged so as to straddle the diameter portion of the wafer W in the radial direction of the rotary table 2 when the wafer W is located below the housing 90. A seal member 11c such as an O-ring is provided between the annular member 82 and the top plate 11 (see FIG. 4).

The internal atmosphere of the vacuum container 1 is airtightly set via the annular member 82 and the housing 90. Specifically, the annular member 82 and the housing 90 are fitted into the opening 11a, and then the upper surface of the annular member 82 and the housing 90 is formed into a frame shape along the contact portion between the annular member 82 and the housing 90. The formed pressing member 91 presses the housing 90 downward in the circumferential direction. Further, the pressing member 91 is fixed to the top plate 11 with a bolt (not shown) or the like. As a result, the internal atmosphere of the vacuum container 1 is set to be airtight. In FIG. 5, the annular member 82 is omitted for simplification of the illustration.

As shown in FIG. 6, on the lower surface of the housing 90, a protrusion extending vertically toward the rotary table 2 so as to surround the plasma processing region P3 on the lower side of the housing 90 along the circumferential direction. 92 is formed. The plasma processing gas nozzles 33 to 35 described above are housed in a region surrounded by the inner peripheral surface of the protrusion 92, the lower surface of the housing 90, and the upper surface of the rotary table 2. The protrusion 92 at the base end portion (inner wall side of the vacuum vessel 1) of the plasma treated gas nozzles 33 to 35 is cut out in a substantially arc shape so as to follow the outer shape of the plasma treated gas nozzles 33 to 35.

As shown in FIG. 4, a protrusion 92 is formed on the lower side (plasma processing region P3) of the housing 90 in the circumferential direction. The seal member 11c is not directly exposed to the plasma by the protrusion 92, that is, is isolated from the plasma processing region P3. Therefore, even if the plasma tries to diffuse from the plasma processing region P3 to, for example, the seal member 11c side, it goes through the lower part of the protrusion 92, so that the plasma is deactivated before reaching the seal member 11c.

Further, as shown in FIG. 4, plasma processing gas nozzles 33 to 35 are provided in the third processing region P3 below the housing 90, and the argon gas supply source 140, the hydrogen gas supply source 141, and the oxygen gas are provided. It is connected to the supply source 142 and the ammonia gas supply source 143. However, either one of the hydrogen gas supply source 141 and the ammonia gas supply source 143 may be provided, and it is not always necessary that both of them are provided.

Further, between the plasma processing gas nozzles 33 to 35 and the argon gas supply source 140, the hydrogen gas supply source 141, the oxygen gas supply source 142, and the ammonia gas supply source 143, the flow rate controllers 130, 131, 132 corresponding to each of them are used. 133 is provided. The argon gas supply source 140, the hydrogen gas supply source 141, the oxygen gas supply source 142, and the ammonia gas supply source 143 supply Ar gas, H ₂ gas, O ₂ gas, and NH ₃ gas to the plasma processing gas nozzles 33 to 35, respectively. .. The flow rates of Ar gas, H ₂ gas, O ₂ gas, and NH ₃ gas are controlled by the flow rate controllers 130, 131, 132, and 133, respectively, and the plasma processing gas nozzles 33 to 35 have a predetermined flow rate ratio (mixing ratio). Be supplied. However, as described above, when only one of the hydrogen gas supply source 141 and the ammonia gas supply source 143 is provided, the flow rate controllers 131 and 133 are also provided according to one of the provided ones. .. For the flow rate controllers 130 to 133, for example, a mass flow controller may be used.

When there is only one plasma processing gas nozzle, for example, the above-mentioned mixed gas of Ar gas, H ₂ gas or NH ₃ gas, and O ₂ gas is supplied to one plasma processing gas nozzle.

FIG. 7 is another cross-sectional view of the plasma source 80 provided in the film forming apparatus of FIG. 1, which is a vertical cross-sectional view of the vacuum vessel 1 cut along the rotation direction of the rotary table 2. As shown in FIG. 7, since the rotary table 2 rotates clockwise during the plasma processing, Ar gas is taken by the rotation of the rotary table 2 from the gap between the rotary table 2 and the protrusion 92. Attempts to invade the lower side of the housing 90. Therefore, in order to prevent the Ar gas from entering the lower side of the housing 90 through the gap, the gas is discharged from the lower side of the housing 90 into the gap. Specifically, the gas discharge holes 36 of the plasma processing gas nozzle 33 are arranged so as to face the gap, that is, to face upstream and downward in the rotation direction of the rotary table 2, as shown in FIGS. 4 and 7. ing. The angle θ of the gas discharge hole 36 of the plasma processing gas nozzle 33 with respect to the vertical axis may be, for example, about 45 ° as shown in FIG. 7, or 90 ° so as to face the inner surface of the protrusion 92. It may be about. That is, the angle θ of the gas discharge hole 36 can be set within a range of about 45 ° to 90 °, which can appropriately prevent the intrusion of Ar gas, depending on the application.

FIG. 8 is an enlarged perspective view of the plasma processing gas nozzles 33 to 35 provided in the plasma processing region P3. As shown in FIG. 8, the plasma processing gas nozzle 33 is a nozzle that can cover the entire recess 24 in which the wafer W is arranged and can supply the plasma processing gas to the entire surface of the wafer W. On the other hand, the plasma processing gas nozzle 34 is a nozzle provided slightly above the plasma processing gas nozzle 33 so as to substantially overlap the plasma processing gas nozzle 33, and has a length of about half that of the plasma processing gas nozzle 33. Further, the plasma processing gas nozzle 35 extends from the outer peripheral wall of the vacuum vessel 1 along the radius on the downstream side of the rotary table 2 of the fan-shaped plasma processing region P3 in the rotation direction, and when it reaches the vicinity of the central region C, it reaches the central region C. It has a shape that is linearly bent along it. Hereinafter, for easy distinction, the plasma processing gas nozzle 33 that covers the whole is referred to as a base nozzle 33, the plasma processing gas nozzle 34 that covers only the outside is referred to as an outer nozzle 34, and the plasma processing gas nozzle 35 extending to the inside is also referred to as a shaft side nozzle 35.

The base nozzle 33 is a gas nozzle for supplying the plasma processing gas to the entire surface of the wafer W, and as described with reference to FIG. 7, the plasma is directed toward the protrusion 92 forming the side surface for partitioning the plasma processing region P3. Discharge the processing gas.

On the other hand, the outer nozzle 34 is a nozzle for mainly supplying the plasma processing gas to the outer region of the wafer W.

The shaft-side nozzle 35 is a nozzle for intensively supplying the plasma processing gas to the central region of the rotary table 2 of the wafer W near the shaft side.

When the number of plasma processing gas nozzles is one, only the base nozzle 33 may be provided.

Next, the Faraday shield 95 of the plasma source 80 will be described in more detail. As shown in FIGS. 4 and 5, the upper side of the housing 90 is made of a metal plate such as copper, which is a conductive plate-like body formed so as to roughly follow the internal shape of the housing 90. , The grounded Faraday Shield 95 is stored. The Faraday Shield 95 includes a horizontal plane 95a that is horizontally locked along the bottom surface of the housing 90, and a vertical plane 95b that extends upward from the outer end of the horizontal plane 95a in the circumferential direction. It may be configured to be substantially hexagonal, for example, visually.

FIG. 9 is a plan view of an example of the plasma source 80 of FIG. 5, showing an example of the plasma source 80 in which the details of the structure of the antenna 83 and the vertical movement mechanism are omitted. FIG. 10 is a perspective view showing a part of the Faraday shield 95 provided in the plasma source 80.

The upper end edges of the Faraday shield 95 on the right side and the left side when the Faraday shield 95 is viewed from the rotation center of the rotary table 2 extend horizontally to the right side and the left side, respectively, to form a support portion 96. Between the Faraday shield 95 and the housing 90, a frame shape that supports the support portion 96 from below and is supported by the flange portion 90a on the central region C side of the housing 90 and the outer edge portion side of the rotary table 2, respectively. A body 99 is provided (see FIG. 5).

When the electric field reaches the wafer W, the electrical wiring or the like formed inside the wafer W may be electrically damaged. Therefore, as shown in FIG. 10, on the horizontal plane 95a, the electric field component of the electric field and the magnetic field (electromagnetic field) generated in the antenna 83 is prevented from moving toward the lower wafer W, and the magnetic field reaches the wafer W. A large number of slits 97 are formed for this purpose.

As shown in FIGS. 9 and 10, the slit 97 is formed at a position below the antenna 83 in the circumferential direction so as to extend in a direction orthogonal to the winding direction of the antenna 83. The slit 97 is formed so as to have a width dimension of about 1/10000 or less of the wavelength corresponding to the high frequency supplied to the antenna 83. Further, on one end side and the other end side in the length direction of each slit 97, a conductive path 97a formed of a grounded conductor or the like is arranged in the circumferential direction so as to close the opening end of the slit 97. Has been done. In the Faraday shield 95, an opening 98 for confirming the light emitting state of plasma is formed in a region outside the formation region of these slits 97, that is, on the central side of the wound region of the antenna 83. ing.

As shown in FIG. 5, on the horizontal plane 95a of the Faraday shield 95, in order to ensure insulation with the plasma source 80 placed above the Faraday shield 95, the thickness dimension is, for example, about 2 mm. Insulating plates 94 made of quartz or the like are laminated. That is, the plasma source 80 is arranged so as to cover the inside of the vacuum vessel 1 (wafer W on the rotary table 2) via the housing 90, the Faraday shield 95, and the insulating plate 94.

Again, other components of the film forming apparatus of one embodiment will be described.

As shown in FIGS. 1 and 2, a side ring 100, which is a cover body, is arranged on the outer peripheral side of the rotary table 2 at a position below the rotary table 2. A first exhaust port 61 and a second exhaust port 62 are formed on the upper surface of the side ring 100 so as to be separated from each other in the circumferential direction. In other words, two exhaust ports are formed on the bottom surface of the vacuum vessel 1, and the side ring 100 at a position corresponding to these exhaust ports has a first exhaust port 61 and a second exhaust port 62. It is formed.

The first exhaust port 61 is located on the separation region D side between the first processing gas nozzle 31 and the separation region D located on the downstream side in the rotation direction of the rotary table 2 with respect to the first processing gas nozzle 31. It is formed in a closer position. The second exhaust port 62 is formed at a position closer to the separation region D side between the plasma source 80 and the separation region D on the downstream side of the rotary table 2 in the rotation direction than the plasma source 80.

The first exhaust port 61 is an exhaust port for exhausting the first processing gas and the separated gas, and the second exhaust port 62 is an exhaust port for exhausting the plasma processing gas and the separated gas. As shown in FIG. 1, each of the first exhaust port 61 and the second exhaust port 62 is a vacuum exhaust mechanism, for example, by means of an exhaust pipe 63 provided with a pressure adjusting unit 65 such as a butterfly valve. It is connected to the pump 64.

As described above, since the housing 90 is arranged from the central region C side to the outer edge side, the gas flowing from the upstream side in the rotation direction of the rotary table 2 with respect to the second processing region P2 The housing 90 may regulate the gas flow toward the second exhaust port 62. Therefore, a groove-shaped gas flow path 101 for flowing gas is formed on the upper surface of the side ring 100 on the outer peripheral side of the housing 90.

As shown in FIG. 1, the central portion of the lower surface of the top plate 11 is formed in a substantially annular shape in the circumferential direction continuously with the portion of the convex portion 4 on the central region C side, and the lower surface thereof. Is provided with a protruding portion 5 formed at the same height as the lower surface (first ceiling surface 44) of the convex portion 4. A labyrinth structure 110 for suppressing mixing of various gases with each other in the central region C is arranged on the upper side of the core portion 21 on the rotation center side of the rotary table 2 with respect to the protrusion 5.

As described above, since the housing 90 is formed up to a position closer to the central region C side, the core portion 21 that supports the central portion of the rotary table 2 has the housing 90 on the upper side portion of the rotary table 2. It is formed on the rotation center side so as to avoid it. Therefore, on the central region C side, various gases are more likely to be mixed than on the outer edge side. Therefore, by forming the labyrinth structure portion 110 on the upper side of the core portion 21, it is possible to increase the flow path of the gas and prevent the gases from mixing with each other.

As shown in FIG. 1, a heater unit 7 which is a heating mechanism is provided in the space between the rotary table 2 and the bottom surface portion 14 of the vacuum vessel 1. The heater unit 7 has a configuration in which the wafer W on the rotary table 2 can be heated to, for example, about room temperature to 700 ° C. via the rotary table 2. In addition, in FIG. 1, a cover member 71 is provided on the side side of the heater unit 7, and a cover member 7a covering the upper side of the heater unit 7 is provided. Further, on the bottom surface portion 14 of the vacuum container 1, purge gas supply pipes 73 for purging the arrangement space of the heater unit 7 are provided at a plurality of locations in the circumferential direction on the lower side of the heater unit 7.

As shown in FIG. 2, the side wall of the vacuum container 1 is formed with a transfer port 15 for transferring the wafer W between the transfer arm 10 and the rotary table 2. The transport port 15 is configured to be airtightly openable and closable from the gate valve G.

Wafer W is delivered to and from the transfer arm 10 at a position facing the transfer port 15 in the recess 24 of the rotary table 2. Therefore, a lifting pin (not shown) and a lifting mechanism (not shown) for lifting the wafer W from the back surface through the recess 24 are provided at a position corresponding to the delivery position on the lower side of the rotary table 2.

Further, the film forming apparatus of one embodiment is provided with a control unit 120 including a computer for controlling the operation of the entire apparatus. A program for performing substrate processing, which will be described later, is stored in the memory of the control unit 120. The program is organized into steps so as to execute various operations of the device, and is installed in the control unit 120 from the storage unit 121, which is a storage medium such as a hard disk, a compact disk, a magneto-optical disk, a memory card, or a flexible disk. Will be done.

The control unit 120 controls the film forming method of one embodiment implemented by the film forming apparatus. Specifically, the control unit 120 specifies the position of the wafer W placed in the recess 24 of the rotary table 2 based on the rotation angle of the rotary shaft 22 acquired from the encoder 25. Then, the control unit 120 ignites the plasma when the product wafer Wp is located in the plasma processing region P3 by controlling the ON / OFF timing of the high frequency power supply 85. The details of the film forming method of one embodiment will be described later.

(Film formation method)
The film forming method of one embodiment will be described by taking as an example a case where a thin film is formed by using the above-mentioned film forming apparatus. Examples of the thin film that can be formed by the film forming method of one embodiment include oxide films such as SiO ₂ , ZrO ₂ , HfO ₂ , TiO ₂ , Al ₂ O ₃ , SiN, HfN, TiN, and AlN nitride films, and ZrAlO. , HfAlO, HfSiON, and other composite membranes that combine the above compounds.

Hereinafter, a case where a thin film of SiO _{2 is formed} by using a silicon-containing gas as a raw material gas, ozone as an oxidation gas, a mixed gas of argon, oxygen, and hydrogen as a plasma processing gas, and argon as a separation gas will be described.

Further, in one embodiment, the product wafer Wp is placed in five recesses 24 of the six recesses 24 of the rotary table 2, and the dummy wafer Wd is placed in the remaining one recess 24 to form a film. explain. The dummy wafer Wd is also called a test wafer and is a wafer for dummies that is repeatedly used during film formation. In one embodiment, the surface is insulated from an oxide film or a nitride film having a film thickness of 0.1 μm to 2 μm. It is a silicon wafer on which a film is deposited. The product wafer Wp is a wafer for a product for forming a product such as a circuit pattern on the surface, and in one embodiment, it is a silicon wafer. The dummy wafer Wd is an example of the first substrate, and the product wafer Wp is an example of the second substrate. As the second substrate, for example, an unused wafer Wn or a monitor wafer Wm may be used instead of the product wafer Wp. As described above, as the second substrate, a wafer in which a thick film, for example, an insulating film having a film thickness of 0.1 μm to 2 μm is not deposited is used on the surface.

In the film forming method of one embodiment, first, the wafer W (product wafer Wp and dummy wafer Wd) is carried into the vacuum vessel 1. When carrying in the wafer W, the gate valve G is opened, and the wafer W is placed on the rotary table 2 by the transfer arm 10 via the transfer port 15 while intermittently rotating the rotary table 2.

Subsequently, with the gate valve G closed and the inside of the vacuum vessel 1 set to a predetermined pressure by the vacuum pump 64 and the pressure adjusting unit 65, the wafer W is brought to a predetermined temperature by the heater unit 7 while rotating the rotary table 2. Heat to. At this time, Ar gas is supplied as the separation gas from the separation gas nozzles 41 and 42. The control unit 120 performs such a series of controls.

Subsequently, a silicon-containing gas is supplied from the first processing gas nozzle 31, ozone gas is supplied from the second processing gas nozzle 32, and the plasma processing gas nozzles 33 to 35 are composed of a mixed gas of argon, oxygen, and hydrogen at a predetermined flow rate. Supply plasma processing gas.

Subsequently, by rotating the rotary table 2, high-frequency power is supplied from the high-frequency power supply 85 to the antenna 83 when the product wafer Wp is located in the plasma processing region P3, and the plasma is ignited to generate plasma. In one embodiment, first, the control unit 120 acquires the rotation angle of the rotation shaft 22 from the encoder 25. Subsequently, the control unit 120 identifies the position of the product wafer Wp placed in the recess 24 of the rotary table 2 based on the acquired rotation angle of the rotary shaft 22, and the product wafer Wp is positioned in the plasma processing region P3. When doing so, the high frequency power supply 85 is turned on. Note that "the product wafer Wp is located in the plasma processing region P3" is not only when all parts of the product wafer Wp are located in the plasma processing region P3, but also a part of the product wafer Wp is located in the plasma processing region P3. Including the case of

On the surface of the wafer W, the silicon-containing gas adsorbed in the first processing region P1 by the rotation of the rotary table 2, and then the silicon-containing gas adsorbed on the wafer W in the second processing region P2 is oxidized by ozone gas. To. As a result, one or a plurality of molecular layers of the silicon oxide film (SiO ₂ ), which is a thin film component, are formed and deposited on the wafer W.

When the rotary table 2 further rotates, the wafer W reaches the plasma processing region P3, and the silicon oxide film is modified by the plasma treatment. In the plasma processing region P3, a mixed gas of Ar / O ₂ / H ₂ is supplied as a plasma processing gas from the base nozzle 33, the outer nozzle 34, and the shaft side nozzle 35. If necessary, the reforming force is weaker than that of the mixed gas supplied from the base nozzle 33 in the region on the central axis side where the angular velocity is slow and the plasma processing amount tends to be large, based on the supply from the base nozzle 33. The flow rate of oxygen may be lowered so as to be. Further, in the region on the outer peripheral side where the angular velocity is high and the plasma processing amount tends to be insufficient, the flow rate of oxygen may be increased so that the reforming force is stronger than that of the mixed gas supplied from the base nozzle 33. Thereby, the influence of the angular velocity of the rotary table 2 can be appropriately adjusted.

By continuing the rotation of the rotary table 2 in such a state, the silicon-containing gas is adsorbed on the wafer W surface, the silicon-containing gas component adsorbed on the wafer W surface is oxidized, and the silicon oxide film which is a reaction product is formed. Plasma modification is performed many times in this order. That is, the film formation process by the ALD method and the modification process of the formed film are performed many times by the rotation of the rotary table 2.

Further, between the first processing region P1 and the second processing region P2 and between the third processing region P3 and the first processing region P1 in the film forming apparatus of one embodiment, the circumference of the rotary table 2 The separation region D is arranged along the direction. Therefore, in the separation region D, each gas is exhausted toward the first exhaust port 61 and the second exhaust port 62 while preventing the mixing of the processing gas and the plasma processing gas.

After repeating such film forming treatment and reforming treatment and reaching a predetermined film thickness of the silicon oxide film, the supply of the silicon-containing gas, ozone gas and plasma processing gas is stopped. Alternatively, the supply of silicon-containing gas and ozone gas is stopped, and only the supply of plasma processing gas is continued. This is because only the modification treatment of the silicon oxide film is continued to form a high-quality silicon oxide film.

After that, the supply of the plasma processing gas is also stopped, the rotation of the rotary table 2 is stopped, and then the processed wafer W is carried out from the vacuum vessel 1.

By the way, in the conventional film forming method, the timing of supplying high frequency power from the high frequency power supply 85 to the antenna 83 is not controlled. Therefore, if the dummy wafer Wd is placed in at least one of the six recesses 24 of the rotary table 2, the dummy wafer Wd is placed in the plasma processing region P3 when the high frequency power supply 85 supplies high frequency power to the antenna 83. May be located. In particular, when the number of dummy wafers Wd placed in the recess 24 is large, the possibility that the dummy wafer Wd is located in the plasma processing region P3 increases when high-frequency power is supplied from the high-frequency power supply 85 to the antenna 83.

In this way, if high-frequency power is supplied from the high-frequency power supply 85 to the antenna 83 to ignite the plasma when the dummy wafer Wd is located in the plasma processing region P3, the plasma ignition time may be delayed or the plasma may not be ignited. is there. In particular, in a high-pressure environment where the pressure of the plasma processing region P3 is 1 Torr (133 Pa) or more, a time delay in plasma ignition and non-ignition of plasma are likely to occur. Further, in the case of an apparatus that separates the inside of the vacuum vessel 1 into a plurality of processing regions by the separation region D like the film forming apparatus of one embodiment, the pressures of the raw material gas adsorption region P1 and the plasma processing region P3 are completely controlled separately. It's difficult to do. For example, it is difficult to set the raw material gas adsorption region P1 to a high pressure of several Torr orders having high adsorption of the raw material gas and the plasma processing region P3 to a low pressure of 0.1 Torr order advantageous for plasma reforming. Therefore, in actual device operation, it may be operated in the vicinity of 2 Torr, which is advantageous for adsorption of raw material gas. Then, the plasma ignition time delay and the plasma non-ignition are likely to occur.

Therefore, in the film forming method of one embodiment, the plasma is ignited when the product wafer Wp is located in the plasma processing region P3. As a result, oxygen adhering to the surface inside the plasma processing region P3 when the plasma is ignited is reduced by oxidizing the surface of the product wafer Wp, and the inside of the plasma processing region P3 can be returned to a charge-neutral state. it can. At this time, from the viewpoint that more oxygen adhering to the surface in the plasma processing region P3 can be reduced, it is preferable to ignite the plasma when all the parts of the product wafer Wp are located in the plasma processing region P3.

When the treatment is completed with the oxygen plasma supplied to the plasma processing region P3, the treatment is completed with oxygen (including oxygen radicals) adhering to the surface of the plasma treatment region P3. In this state, the processed wafer W is carried out, and then a new wafer W to be subjected to the film forming process is carried into the vacuum vessel 1, and when the plasma is ignited, the dummy wafer Wd is located in the plasma processing region P3. If so, the plasma ignition time may be delayed or the plasma may not be ignited. That is, in the first film forming process, the plasma ignition is smooth, but in the second and subsequent film forming processes, the plasma ignition may not be successful.

This is thought to be due to the very high electronegativity of oxygen and the very high ability to capture electrons. It is considered that the state in which the plasma is easily ignited is a state in which charges such as electrons and cations are easily generated in the space. Plasma is a state in which the molecules that make up the gas are ionized and move separately into cations and electrons. Since plasma is a gas that contains charged particles generated by ionization, an environment in which charged particles are likely to be generated. Naturally, plasma is likely to be generated. That is, the environment in which charged particles are likely to be generated is considered to be an environment in which ignition is likely to occur.

When oxygen adheres to the surface of the plasma processing region P3, for example, the ceiling surface of the housing 90, the inner peripheral surface of the protrusion 92, etc., the plasma processing gas is supplied, and high frequency power is supplied to the antenna 83 to discharge the plasma. However, the ionized electrons can be immediately captured by the oxygen on the surface. Therefore, it is considered that sufficient charged particles are less likely to be accumulated in the plasma processing region P3.

(Example)
An example in which the film forming method of one embodiment is carried out and the ignitability of plasma is evaluated will be described.

In the first embodiment, when the unused wafer Wn, which is the second substrate, is located in the plasma processing region P3, high frequency power is supplied from the high frequency power supply 85 to the antenna 83 to ignite the plasma. Then, the ignitability of the plasma was evaluated by measuring the Vpp of the high-frequency power before and after igniting the plasma. In Example 1, the evaluation of the ignitability of the plasma was repeated 10 times (from the first run to the tenth run). Note that Vpp (Volt peak to peak) is the voltage difference from the peak value to the peak value of the high frequency voltage applied from the high frequency power supply 85 to the antenna 83.

Specifically, first, the unused wafer Wn was placed in one of the six recesses 24 of the rotary table 2 of the film forming apparatus described above, and the dummy wafer Wd was placed in the remaining five recesses 24. Subsequently, Ar gas was discharged as the separation gas from the separation gas nozzles 41 and 42, and Ar gas was discharged from the separation gas supply pipe 51 and the purge gas supply pipe 72. Further, the pressure adjusting unit 65 adjusted the inside of the vacuum vessel 1 to 1.8 Torr (240 Pa), which is a preset processing pressure.

Subsequently, the wafer W (unused wafer Wn and dummy wafer Wd) was heated by the heater unit 7 while rotating the rotary table 2 clockwise. Further, a mixed gas of Ar gas (15 slm) and NH ₃ gas (100 sccm) was supplied as the plasma processing gas from the plasma processing gas nozzles 33, 34, 35.

Subsequently, as shown in FIG. 11, the rotary table 2 is rotated, and when the unused wafer Wn is located in the plasma processing region P3, a high frequency having a frequency of 13.56 MHz with respect to the antenna 83 from the high frequency power supply 85 Electric power (1500 W) was supplied to ignite the plasma. The rotation speed of the rotary table 2 was set to 15 rpm. In addition, the ignitability of the plasma was evaluated by measuring the Vpp of the high-frequency power before and after igniting the plasma.

FIG. 12 is a diagram showing the evaluation result of the ignitability of the plasma in Example 1, and shows the result of measuring the Vpp of the high frequency power before and after igniting the plasma. 12 (a), 12 (b) and 12 (c) show the measurement results of the first run, the second run and the third run, respectively. Further, in FIGS. 12A to 12C, the horizontal axis represents time [seconds] and the vertical axis represents Vpp [V], and the time when the plasma is ignited (high-frequency power is applied from the high-frequency power supply 85 to the antenna 83). The time of supply) is indicated by time t1.

As shown in FIGS. 12 (a) to 12 (c), in all the runs from the first run to the third run, the value of Vpp was changed after about 1.5 seconds had elapsed from the time t1 when the plasma was ignited. It can be seen that the transition to the stable state has occurred. From this result, it can be said that in the first embodiment, the plasma can be ignited in a short time and the plasma discharge can be stably generated.

Note that FIG. 12 does not show the result of measuring the Vpp of the 4th to 10th runs of Example 1, but the plasma is ignited in the 4th to 10th runs as well as in the 1st to 3rd runs. The value of Vpp transitioned to the stable state after about 1.5 seconds had elapsed from the time t1.

In addition, the following Comparative Example 1 was carried out for the comparison of Example 1. In Comparative Example 1, as shown in FIG. 13, when the dummy wafer Wd, which is the first substrate, is located in the plasma processing region P3, high-frequency power is supplied from the high-frequency power supply 85 to the antenna 83 to ignite the plasma. Then, the ignitability of the plasma was evaluated by measuring the Vpp of the high-frequency power before and after igniting the plasma. In Comparative Example 1, the evaluation of plasma ignition was repeated twice (from the first run to the second run). The timing of igniting the plasma is the same as that of the first embodiment.

FIG. 14 is a diagram showing the evaluation result of the ignitability of the plasma in Comparative Example 1, and shows the result of measuring the Vpp of the high frequency power before and after igniting the plasma. 14 (a) and 14 (b) show the measurement results of the first run and the second run, respectively. In FIGS. 14 (a) and 14 (b), the horizontal axis indicates time [seconds], the vertical axis indicates Vpp [V], and the time when the plasma is ignited (high frequency power is applied from the high frequency power supply 85 to the antenna 83). The time of supply) is indicated by time t2.

As shown in FIG. 14A, in the first run, the value of Vpp transitions to the stable state about 1.5 seconds after the time t2 at which the plasma is ignited. However, as shown in FIG. 14 (b), in the second run, it can be seen that the value of Vpp continues to rise without being stable after igniting the plasma. In the second run, the reason why the Vpp value became 0V after rising was determined to be that the plasma was not ignited because the Vpp value did not transition to the stable state within the predetermined time. This is because the high frequency power supply 85 was turned off. As described above, in Comparative Example 1, it can be seen that the ignitability of the plasma is poor.

From the evaluation results of Example 1 and Comparative Example 1, it can be said that the plasma discharge can be stably generated by igniting the plasma when the unused wafer Wn is located in the plasma processing region P3.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The above-described embodiment may be omitted, replaced, or changed in various forms without departing from the scope and purpose of the appended claims.

In the above embodiment, the case where the raw material gas adsorption region P1, the oxidation region P2, and the plasma processing region P3 are provided apart from each other along the rotation direction of the rotary table 2 will be described. The present invention is not limited, and for example, a plurality of plasma processing regions P3 may be provided. In this case, in each plasma processing region P3, as described in the film forming method described above, when the product wafer Wp is located in the plasma processing region P3, high frequency power is supplied from the high frequency power supply 85 to the antenna 83. The plasma may be ignited to generate the plasma.

1 Vacuum container 2 Rotating table 80 Plasma source 83 Antenna 85 High frequency power supply P1 Raw material gas adsorption region P2 Oxidation region P3 Plasma processing region W Wafer Wd Dummy wafer Wm Monitor wafer Wn Unused wafer Wp Product wafer

Claims (10)

A plurality of substrates including at least a first substrate for dummy and a second substrate different from the first substrate are mounted on a rotary table provided in the processing chamber and capable of mounting the substrate on the upper surface along the circumferential direction. The process of placing and
A step of modifying a film formed on the substrate by using radicals generated by a plasma source in a plasma processing region in the processing chamber while rotating the rotary table.
Have,
In the reforming step, the plasma is ignited when the second substrate is located in the plasma processing region.
Film formation method. The process of adsorbing the raw material gas on the substrate and
A step of oxidizing the raw material gas adsorbed on the substrate to deposit a molecular layer of the film, and
Have,
The film forming method according to claim 1. The raw material gas adsorption region, the oxidation region, and the plasma processing region are arranged above the rotary table so as to be separated from each other along the rotation direction of the rotary table, and the rotary table is rotated a plurality of times in the rotation direction. The step of adsorbing, the step of depositing, and the step of reforming by passing the raw material gas adsorption region, the oxidation region, and the plasma processing region through the substrate on the rotary table in this order are repeated.
The film forming method according to claim 2. The second substrate is a product wafer, a monitor wafer or an unused wafer.
The film forming method according to any one of claims 1 to 3. An insulating film is formed on the surface of the first substrate.
The film forming method according to claim 4. The film thickness of the insulating film is 0.1 μm to 1 μm.
The film forming method according to claim 5. The plasma is an inductively coupled plasma generated by using an antenna.
The film forming method according to any one of claims 1 to 6. The reforming step is performed by converting a plasma processing gas containing an oxygen gas supplied into the plasma processing region into plasma by the plasma source.
The film forming method according to any one of claims 1 to 7. The film is an oxide film,
The film forming method according to any one of claims 1 to 8. With the processing room
A rotary table provided in the processing chamber on which the substrate is placed on the upper surface along the circumferential direction,
A first processing gas supply unit and a second processing gas supply unit that supply a first processing gas and a second processing gas to regions separated from each other in the circumferential direction of the rotary table via a separation region, respectively.
A plasma processing gas supply unit that supplies plasma processing gas to the processing chamber in order to perform plasma processing on the substrate,
A plasma processing region that surrounds the plasma processing gas supply unit from above and from the side,
A plasma source provided so as to face the rotary table and generating plasma in the plasma processing region in order to convert the plasma processing gas into plasma,
The plasma processing gas is supplied from the plasma processing gas supply unit in a state where a plurality of substrates including at least a dummy first substrate and a second substrate different from the first substrate are placed on the rotary table. At the same time, when the second substrate is located in the plasma processing region, the plasma source is driven to ignite the plasma in the plasma processing region.
Film forming equipment.

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