JP2017120884A - Protection film-forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protection film-forming method by which a protection film can be formed at a desired position in a self-alignment manner.SOLUTION: A protection film-forming method is arranged so that a protection film 62 is formed on a surface U of each non-trench formation region between a plurality of adjacent trenches T of a substrate W with the plurality of trenches T formed in a surface of the substrate. The method comprises: a material gas adsorption step for supplying a material gas including an organic metal gas or organic semimetal gas to the substrate surface involving the plurality of trenches to cause the adsorption of the material gas onto the surface of the substrate; and an oxidation step for supplying an oxidation gas onto the substrate surface to oxidize the material gas adsorbing the substrate surface, thereby growing an oxide film of an organic metal or organic semimetal included in the material gas. In the method, the material gas adsorption step and the oxidation step are repeatedly executed in a repetition cycle of 90 to 300 times per minute.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a protective film forming method.

Conventionally, a LOCOS oxide film is formed on the surface of a silicon layer, impurities are implanted into the silicon layer to form an impurity region, an SiN layer and an SiO ₂ layer are stacked on the silicon layer, and SiN layer is formed by photolithography and etching. A method of manufacturing a semiconductor device is known in which openings are selectively formed in a layer and a SiO ₂ layer, and trenches are formed in a LOCOS oxide film and a silicon layer using the openings as a mask (see, for example, Patent Document 1).

JP 2010-103242 A

  However, with the recent progress of miniaturization, it is becoming difficult to accurately drop the contact hole with respect to the desired target. In addition, it is becoming difficult to manufacture a mask for forming a contact hole having the same dimensions as the target. In order to avoid these problems, it is necessary to form a protective film that does not etch except the desired part even if an alignment error occurs. However, the protective film is left locally due to the limit of lithography accuracy. It is very difficult. In order to solve these problems, it is desired to provide a method capable of forming a protective film in a self-aligned manner only at a desired position.

  Therefore, an object of the present invention is to provide a protective film forming method capable of forming a protective film in a self-aligned manner at a desired position.

In order to achieve the above object, a method for forming a protective film according to one embodiment of the present invention includes forming a plurality of recess shapes on a surface of a substrate, and forming a non-depression shape forming region between the plurality of adjacent recess shapes on the surface. A protective film forming method for forming a protective film,
A source gas adsorption step of supplying a source gas composed of an organic metal gas or an organic metalloid gas onto the surface of the substrate including the plurality of recess shapes, and adsorbing the source gas on the surface of the substrate;
An oxidizing gas is supplied onto the surface of the substrate including the plurality of depressions, the source gas adsorbed on the surface of the substrate is oxidized, and an organic metal or organic metalloid oxide film contained in the source gas is formed. An oxidation step of forming a film,
The source gas adsorption step and the oxidation step are repeatedly performed at a repetition cycle of 90 to 300 times per minute.

  According to the present invention, a protective film can be locally formed in a region between recess shapes such as a trench structure or a hole structure.

It is a schematic sectional drawing which shows the film-forming apparatus which concerns on embodiment of this invention. It is a schematic perspective view which shows the structure in the vacuum vessel of the film-forming apparatus of FIG. It is a schematic plan view which shows the structure in the vacuum vessel of the film-forming apparatus of FIG. It is a schematic sectional drawing of the vacuum vessel along the concentric circle of the turntable of the film-forming apparatus of FIG. It is another schematic sectional drawing of the film-forming apparatus of FIG. It is a schematic sectional drawing which shows the plasma generation source provided in the film-forming apparatus of FIG. It is another schematic sectional drawing which shows the plasma generation source provided in the film-forming apparatus of FIG. It is a schematic top view which shows the plasma generation source provided in the film-forming apparatus of FIG. It is a figure for demonstrating an example of the protective film formation method which concerns on embodiment of this invention. FIG. 9A is a diagram showing an example of the surface pattern of the wafer W used in the protective film forming method according to the present embodiment. FIG. 9B is a diagram showing an example of the source gas adsorption process. FIG. 9C is a first diagram showing an example of the oxidation process. FIG. 9D is a second diagram showing an example of the oxidation process. FIG. 9E is a diagram showing an example of the reforming process. FIG. 9F is a diagram showing an example of the source gas adsorption process repeated again. It is the table | surface which showed the example of the source gas which can apply the protective film formation method which concerns on embodiment of this invention. It is the figure which showed the implementation result of the protective film formation method which concerns on the Example of this invention with the implementation result of the protective film formation method which concerns on a comparative example. FIG. 11A is a diagram showing an implementation result of the protective film forming method according to Comparative Example 1. FIG. FIG. 11B is a diagram showing an implementation result of the protective film forming method according to Comparative Example 2. FIG. 11C is a diagram showing an implementation result of the protective film forming method according to the first embodiment. FIG. 11 (d) is a diagram showing an implementation result of the protective film formation method according to Example 2. It is the figure which showed the implementation result of the protective film formation method which concerns on Example 3. FIG. FIG. 12A is a diagram showing an implementation result of 0 seconds from the start of film formation. FIG. 12B is a diagram showing an implementation result for 180 seconds from the start of film formation. FIG. 12C is a diagram showing a result of implementation for 240 seconds from the start of film formation. FIG. 12D is a diagram showing an implementation result for 300 seconds from the start of film formation. FIG. 12 (e) is a diagram showing the result of 360 seconds from the start of film formation. It is the figure which showed the implementation result of the protective film formation method which concerns on the comparative examples 3 and 4. FIG. FIG. 13A is a diagram showing an implementation result of the protective film forming method according to Comparative Example 3. FIG. 13B is a diagram showing an implementation result of the protective film forming method according to Comparative Example 4. It is the figure which showed the implementation result of the protective film formation method which concerns on Example 4. FIG. FIG. 14A is a diagram showing a state in which a protective film is formed by film formation. FIG. 14B is a diagram showing a state after wet etching is performed on the protective film from the state of FIG. It is the figure which showed the implementation result of the protective film formation method which concerns on Example 5. FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[Film deposition system]
First, a film forming apparatus suitable for carrying out the protective film forming method according to the embodiment of the present invention will be described. The protective film forming method according to the embodiment of the present invention can be implemented by various film forming apparatuses as long as the type of gas supplied to the substrate can be switched at high speed, and the form of the film forming apparatus is not limited. Here, an example of a film forming apparatus capable of performing a film forming process for switching the type of gas supplied to the substrate at high speed will be described.

  Referring to FIGS. 1 to 3, a film forming apparatus includes a flat vacuum vessel 1 having a substantially circular plane shape, and a rotary table 2 provided in the vacuum vessel 1 and having a rotation center at the center of the vacuum vessel 1. And. The vacuum container 1 is a processing chamber for performing a film forming process on the surface of a wafer accommodated therein. The vacuum vessel 1 is a container body 12 having a bottomed cylindrical shape, and a ceiling that is detachably attached to the upper surface of the container body 12 through a seal member 13 (FIG. 1) such as an O-ring, for example. And a plate 11.

  The rotary table 2 is fixed to a cylindrical core portion 21 at the center, and the core portion 21 is fixed to the upper end of a rotary shaft 22 extending in the vertical direction. The rotary shaft 22 penetrates the bottom 14 of the vacuum vessel 1 and the lower end is attached to a drive unit 23 that rotates the rotary shaft 22 (FIG. 1) about the vertical axis. The rotating shaft 22 and the drive unit 23 are accommodated in a cylindrical case body 20 whose upper surface is open. The flange portion provided on the upper surface of the case body 20 is airtightly attached to the lower surface of the bottom portion 14 of the vacuum vessel 1, and the airtight state between the internal atmosphere and the external atmosphere of the case body 20 is maintained.

  Although details will be described later, in the protective film forming method according to the embodiment of the present invention, the rotary table 2 is rotated at a high speed at a predetermined speed in the range of 90 rpm to 300 rpm, more preferably in the range of 120 to 300 rpm. Therefore, the drive part 23 is comprised so that the high speed rotation of the turntable 2 is possible in the range of 90 rpm or more and 300 rpm or less. In general film formation processes, the rotation speed of the turntable 2 is often set to about 20 to 30 rpm.

  As shown in FIGS. 2 and 3, a semiconductor wafer (hereinafter referred to as “wafer”) W that is a plurality of (five in the illustrated example) substrates along the rotation direction (circumferential direction) is provided on the surface portion of the turntable 2. Is provided with a circular recess 24 for mounting the. In FIG. 3, for convenience, the wafer W is shown in only one recess 24. The recess 24 has an inner diameter slightly larger than the diameter of the wafer W, for example, 4 mm, and a depth substantially equal to the thickness of the wafer W. Therefore, when the wafer W is accommodated in the recess 24, the surface of the wafer W and the surface of the turntable 2 (regions where the wafer W is not placed) are at the same height. On the bottom surface of the recess 24, a through hole (not shown) through which, for example, three lifting pins for supporting the back surface of the wafer W to raise and lower the wafer W is formed.

  2 and 3 are diagrams for explaining the structure inside the vacuum vessel 1, and the top plate 11 is not shown for convenience of explanation. As shown in FIGS. 2 and 3, a reaction gas nozzle 31, a reaction gas nozzle 32, a reaction gas nozzle 33, and separation gas nozzles 41 and 42 each made of, for example, quartz are disposed above the turntable 2 in the circumferential direction (rotation) of the vacuum vessel 1. They are arranged at intervals in the rotation direction of the table 2 (arrow A in FIG. 3). In the illustrated example, the separation gas nozzle 41, the reaction gas nozzle 31, the separation gas nozzle 42, the reaction gas nozzle 32, and the reaction gas nozzle 33 are arranged in this order in a clockwise direction (a rotation direction of the turntable 2) from a later-described transfer port 15. . These nozzles 31, 32, 33, 41, and 42 have gas introduction ports 31 a, 32 a, 33 a, 41 a, and 42 a (FIG. 3) that are the base ends of the nozzles 31, 32, 33, 41, and 42 (FIG. 3). By being fixed to the outer peripheral wall of 12, the vacuum vessel 1 is introduced into the vacuum container 1 from the outer peripheral wall, and is attached so as to extend horizontally with respect to the rotary table 2 along the radial direction of the container main body 12.

In the present embodiment, as shown in FIG. 3, the reactive gas nozzle 31 is connected to a source gas supply source 130 via a pipe 110 and a flow rate controller 120. The reactive gas nozzle 32 is connected to an oxidizing gas (H ₂ O, H ₂ O ₂ , O _2, or O ₃ ) supply source 131 via a pipe 111 and a flow rate controller 121. Further, the reactive gas nozzle 33 is connected to a rare gas (Ar, etc.) supply source 132 and an additive gas (O _2, H _2, etc.) supply source 133 via a pipe 112 and a flow rate controller 122. The separation gas nozzles 41 and 42 are both connected to a separation gas supply source (not shown) via a pipe and a flow rate control valve (not shown). As the separation gas, a rare gas such as helium (He) or argon (Ar) or an inert gas such as nitrogen (N ₂ ) gas can be used. In this embodiment, an example using N ₂ gas will be described.

The reactive gas nozzle 32 may be connected to a nitriding gas supply source. When the nitriding process is performed by supplying the nitriding gas from the reaction gas nozzle 32, the oxidant gas supply source 131 of FIG. 3 is filled with a nitriding gas such as an NH ₃ -containing gas or an N ₂ -containing gas. Can function. In this case, the reactive gas nozzle 32 is connected to the nitriding gas (NH ₃ or N ₂ ) supply source 131 via the pipe 111 and the flow rate controller 121 as shown in FIG.

  The reaction gas nozzles 31, 32, 33 have a plurality of gas discharge holes 35 (see FIG. 4) that open toward the turntable 2 along the length direction of the reaction gas nozzles 31, 32, 33, for example, at an interval of 10 mm. Are arranged in A region below the reactive gas nozzle 31 is a first processing region P1 for adsorbing the source gas to the wafer W. The lower region of the reaction gas nozzle 32 supplies an oxidizing gas that oxidizes the raw material gas adsorbed on the wafer W in the first processing region P1, and by thermal oxidation, an organic metal or organic semi-metal oxide contained in the raw material gas is supplied. It becomes the 2nd processing field P2 which generates a molecular layer as a reaction product. Note that a molecular layer of an organic metal oxide or an organic metalloid oxide forms a protective film to be formed. The lower region of the reactive gas nozzle 33 supplies a rare gas and an additive gas into plasma to the organometallic oxide or organometalloid oxide (protective film) generated by thermal oxidation in the second processing region P2, and plasma treatment ( This is the third processing region P3 where the reforming process is performed. Here, since the first processing region P1 is a region for supplying a source gas, it may be called a source gas supply region P1. Similarly, since the second processing region P2 is a region for supplying an oxidizing gas for performing thermal oxidation, it may be called an oxidizing gas supply region P2. Further, since the third processing region P3 is a region for supplying plasma gas (rare gas and additive gas) for performing plasma processing, it may be referred to as a plasma gas supply region P3.

  Even when the nitriding gas is supplied from the reactive gas nozzle 32, the lower region of the reactive gas nozzle 32 becomes the second processing region P2. In this case, in the second processing region P2, a nitriding gas for nitriding the source gas adsorbed on the wafer W in the first processing region P1 is supplied, and an organic metal or organic semimetal contained in the source gas is formed by thermal nitridation. A molecular layer of nitride is produced as a reaction product. The molecular layer of the organic metal nitride or organic metalloid nitride constitutes a protective film to be formed. The region below the reactive gas nozzle 33 supplies a rare gas and an additive gas in plasma form to the organometallic nitride or organometalloid nitride (protective film) generated by thermal nitridation in the second treatment region P2, and plasma treatment ( The point of becoming the third processing region P3 where the reforming process is performed is the same as in the case of oxidation. In this case, since the second processing region P2 is a region for supplying an oxidizing gas for performing thermal oxidation, it may be called a nitriding gas supply region P2. Moreover, both may be integrated and the 2nd process area | region P2 may be called the oxynitride gas supply area | region P2.

  Note that the third processing region P3 is not necessarily provided. That is, the modification process using plasma is optional, and only the thermal oxidation process or the thermal nitridation process may be performed in the second processing region P2. In this case, the plasma generator 80 and the reactive gas nozzle 33 need not be provided.

  On the other hand, when the third processing region P3 is provided, the plasma generator 80 is provided above the third processing region P3, and the reactive gas nozzle 33 is also provided.

As yet another aspect, only the third processing region P3 may be provided without providing the second processing region P2. In this case, in the third processing region P3, an oxidizing gas such as O ₂ gas is supplied as an additive gas, and only the plasma oxidation process using the plasma generator 80 is performed, and the thermal oxidation process is not performed. In this case, the oxidation process and the reforming process are performed simultaneously. Therefore, the reactive gas nozzle 32 may not be provided, and the reactive gas nozzle 33 and the plasma generator 80 are provided. In any case, the reaction gas nozzle 31 is always provided, and at least one of the reaction gas nozzles 32 and 33 is provided. Moreover, it is preferable that the separation gas nozzles 41 and 42 are also provided in any case.

Similarly, in the nitriding process, the second processing region P2 may not be provided, and only the third processing region P3 may be provided. In this case, in the third processing region P3, a nitriding gas such as NH ₃ gas is supplied as an additive gas, and only the plasma nitriding process using the plasma generator 80 is performed, and the thermal nitriding process is not performed. In this case, the nitriding process and the modifying process are performed simultaneously.

  As described above, the method for forming a protective film according to the embodiment of the present invention can be provided with various oxidation processes and nitridation processes, and the configuration of the film forming apparatus can be set in various modes according to this.

  In FIG. 3, the plasma generator 80 is simplified by a broken line. Details of the plasma generator 80 will be described later.

The source gas supplied from the reaction gas nozzle 33 is an organic metal gas or an organic metalloid gas. As the source gas, various organic metal gases or organic metalloid gases can be used, and are selected according to the type of protective film to be formed. For example, the organometallic gas used for forming the high-k film may be used as the organometallic gas. The organic metal gas may be a gas containing various organic metals. For example, when forming a protective film of TiO ₂ , a gas containing organic amino titanium such as TDMAT (tetrakisdimethylaminotitanium) is selected. The The organic metalloid gas may be an organic silane gas, for example, an organic aminosilane gas such as 3DMASi.

In addition, as the oxidizing gas supplied from the reactive gas nozzle 32, various oxidizing gases can be used as long as the oxidizing gas can react with the supplied organometallic gas to generate an organometallic oxide. When the organic metal gas is oxidized by thermal oxidation, H ₂ O, H ₂ O ₂ , O ₂ , O ₃ or the like is selected.

Similarly, as the nitriding gas supplied from the reactive gas nozzle 32, various nitriding gases can be used as long as they are oxidizing gases that can react with the supplied organometallic gas to generate organometallic nitride. For example, when the organometallic gas is nitrided by thermal oxidation, an NH ₃ -containing gas is selected, and when the organometallic gas is nitrided by plasma nitriding, an NH ₃ -containing gas or an N ₂ -containing gas is selected.

As the noble gas supplied from the reactive gas nozzle 33, Ar gas or He gas suitable for plasmatization is selected, and O ₂ gas or H ₂ gas or the like is selected as an additive gas.

  Referring to FIGS. 2 and 3, two convex portions 4 are provided in the vacuum vessel 1. Since the convex portion 4 constitutes the separation region D together with the separation gas nozzles 41 and 42, the convex portion 4 is attached to the back surface of the top plate 11 so as to protrude toward the turntable 2 as described later. The convex portion 4 has a fan-like planar shape with the top portion cut into an arc shape. In the present embodiment, the inner arc is connected to the protruding portion 5 (described later), and the outer arc is a vacuum vessel. It arrange | positions so that the inner peripheral surface of one container main body 12 may be met.

  FIG. 4 shows a cross section of the vacuum vessel 1 along the concentric circle of the rotary table 2 from the reaction gas nozzle 31 to the reaction gas nozzle 32. As shown in the figure, since the convex portion 4 is attached to the back surface of the top plate 11, a flat low ceiling surface 44 (first ceiling surface) which is the lower surface of the convex portion 4 is provided in the vacuum vessel 1. There are ceiling surfaces 45 (second ceiling surfaces) located on both sides in the circumferential direction of the ceiling surface 44 and higher than the ceiling surface 44. The ceiling surface 44 has a fan-shaped planar shape with a top portion cut into an arc shape. Further, as shown in the figure, the convex portion 4 is formed with a groove 43 formed so as to extend in the radial direction at the center in the circumferential direction, and the separation gas nozzle 42 is accommodated in the groove 43. A groove 43 is similarly formed in the other convex portion 4, and a separation gas nozzle 41 is accommodated therein. In addition, reaction gas nozzles 31 and 32 are provided in the space below the high ceiling surface 45, respectively. These reaction gas nozzles 31 and 32 are provided in the vicinity of the wafer W so as to be separated from the ceiling surface 45. As shown in FIG. 4, the reactive gas nozzle 31 is provided in the right space 481 below the high ceiling surface 45, and the reactive gas nozzle 32 is provided in the left space 482 below the high ceiling surface 45.

  Further, the separation gas nozzles 41 and 42 accommodated in the groove portion 43 of the convex portion 4 have a plurality of gas discharge holes 41 h (see FIG. 4) that open toward the rotary table 2, and the length of the separation gas nozzles 41 and 42. Along the direction, for example, they are arranged at intervals of 10 mm.

The ceiling surface 44 forms a separation space H that is a narrow space with respect to the turntable 2. When N ₂ gas is supplied from the discharge hole 42 h of the separation gas nozzle 42, the N ₂ gas flows toward the space 481 and the space 482 through the separation space H. At this time, since the volume of the separation space H is smaller than the volume of the spaces 481 and 482, the pressure of the separation space H can be made higher than the pressure of the spaces 481 and 482 by N ₂ gas. That is, a separation space H having a high pressure is formed between the spaces 481 and 482. Further, the N ₂ gas flowing out from the separation space H to the spaces 481 and 482 serves as a counter flow for the first reaction gas from the first region P1 and the second reaction gas from the second region P2. Therefore, the first reaction gas from the first region P1 and the second reaction gas from the second region P2 are separated by the separation space H. Therefore, mixing and reaction of the first reaction gas and the second reaction gas in the vacuum container 1 is suppressed.

The height h1 of the ceiling surface 44 with respect to the upper surface of the turntable 2 takes into account the pressure in the vacuum vessel 1 during film formation, the rotation speed of the turntable 2, the supply amount of separation gas (N ₂ gas) to be supplied, and the like. In addition, it is preferable to set the pressure in the separation space H to a height suitable for increasing the pressure in the spaces 481 and 482.

  On the other hand, a protrusion 5 (FIGS. 2 and 3) surrounding the outer periphery of the core portion 21 that fixes the rotary table 2 is provided on the lower surface of the top plate 11. In this embodiment, the protruding portion 5 is continuous with a portion on the rotation center side of the convex portion 4, and the lower surface thereof is formed at the same height as the ceiling surface 44.

  FIG. 1 referred to above is a cross-sectional view taken along the line II ′ of FIG. 3 and shows a region where the ceiling surface 45 is provided. On the other hand, FIG. 5 is a cross-sectional view showing a region where the ceiling surface 44 is provided. As shown in FIG. 5, a bent portion 46 that bends in an L shape so as to be opposed to the outer end surface of the rotary table 2 at the peripheral portion of the fan-shaped convex portion 4 (a portion on the outer edge side of the vacuum vessel 1). Is formed. Similar to the convex portion 4, the bent portion 46 suppresses the reaction gas from entering from both sides of the separation region D and suppresses the mixing of both reaction gases. The fan-shaped convex portion 4 is provided on the top plate 11 so that the top plate 11 can be removed from the container body 12, so that there is a slight gap between the outer peripheral surface of the bent portion 46 and the container body 12. There is. The gap between the inner peripheral surface of the bent portion 46 and the outer end surface of the turntable 2 and the gap between the outer peripheral surface of the bent portion 46 and the container body 12 are, for example, the same dimensions as the height of the ceiling surface 44 with respect to the upper surface of the turntable 2. Is set to

  As shown in FIG. 4, the inner peripheral wall of the container main body 12 is formed in a vertical plane close to the outer peripheral surface of the bent portion 46 as shown in FIG. 4. As shown, for example, it is recessed outward from the portion facing the outer end surface of the turntable 2 to the bottom 14. Hereinafter, for convenience of explanation, a recessed portion having a substantially rectangular cross-sectional shape is referred to as an exhaust region. Specifically, an exhaust region communicating with the first processing region P1 is referred to as a first exhaust region E1, and regions communicating with the second and third processing regions P2, P3 are referred to as a second exhaust region E2. . As shown in FIGS. 1 to 3, a first exhaust port 610 and a second exhaust port 620 are formed at the bottoms of the first exhaust region E1 and the second exhaust region E2, respectively. . As shown in FIG. 1, the first exhaust port 610 and the second exhaust port 620 are connected to, for example, a vacuum pump 640 that is a vacuum exhaust unit via an exhaust pipe 630. A pressure controller 650 is provided between the vacuum pump 640 and the exhaust pipe 630.

  As shown in FIGS. 1 and 4, a heater unit 7 serving as a heating unit is provided in the space between the turntable 2 and the bottom 14 of the vacuum vessel 1, and the wafer on the turntable 2 is interposed via the turntable 2. W is heated to a temperature determined in the process recipe (for example, 150 ° C.). On the lower side near the periphery of the turntable 2, the lower area of the turntable 2 is partitioned by dividing the atmosphere from the upper space of the turntable 2 to the exhaust areas E1 and E2 and the atmosphere in which the heater unit 7 is placed. A ring-shaped cover member 71 is provided to suppress gas intrusion into the substrate (FIG. 5). This cover member 71 is provided between the outer edge of the turntable 2 and an inner member 71 a provided so that the outer peripheral side faces the lower side from the outer edge, and between the inner member 71 a and the inner wall surface of the vacuum vessel 1. An outer member 71b. The outer member 71b is provided close to the bent portion 46 below the bent portion 46 formed at the outer edge portion of the convex portion 4 in the separation region D, and the inner member 71a is provided below the outer edge portion of the turntable 2. The heater unit 7 is surrounded over the entire circumference (and below the portion slightly outside the outer edge).

The bottom portion 14 at a portion closer to the rotation center than the space where the heater unit 7 is disposed protrudes upward so as to approach the core portion 21 near the center portion of the lower surface of the turntable 2 to form a protrusion 12a. Yes. The space between the projecting portion 12a and the core portion 21 is a narrow space, and the gap between the inner peripheral surface of the through hole of the rotary shaft 22 penetrating the bottom portion 14 and the rotary shaft 22 is narrow, and these narrow spaces are formed. The space communicates with the case body 20. The case body 20 is provided with a purge gas supply pipe 72 for supplying N ₂ gas as a purge gas into a narrow space for purging. A plurality of purge gas supply pipes 73 for purging the arrangement space of the heater unit 7 are provided at the bottom 14 of the vacuum vessel 1 at predetermined angular intervals in the circumferential direction below the heater unit 7 (FIG. 5). Shows one purge gas supply pipe 73). In addition, between the heater unit 7 and the turntable 2, in order to suppress gas intrusion into the region where the heater unit 7 is provided, the protruding portion 12a from the inner peripheral wall of the outer member 71b (the upper surface of the inner member 71a). A lid member 7a is provided to cover the space between the upper end portion of the cover member and the upper end portion in the circumferential direction. The lid member 7a can be made of quartz, for example.

Further, a separation gas supply pipe 51 is connected to the central portion of the top plate 11 of the vacuum vessel 1 so that N ₂ gas as separation gas is supplied to the space 52 between the top plate 11 and the core portion 21. It is configured. The separation gas supplied to the space 52 is discharged toward the periphery along the surface of the turntable 2 on the wafer mounting region side through a narrow gap 50 between the protrusion 5 and the turntable 2. The space 50 can be maintained at a higher pressure than the spaces 481 and 482 by the separation gas. Therefore, the space 50 suppresses mixing of the organometallic gas supplied to the first processing region P1 and the oxidizing gas supplied to the second processing region P2 through the central region C. That is, the space 50 (or the center region C) can function in the same manner as the separation space H (or the separation region D).

  Further, as shown in FIGS. 2 and 3, a transfer port 15 for transferring a wafer W as a substrate between the external transfer arm 10 and the rotary table 2 is formed on the side wall of the vacuum vessel 1. ing. The transport port 15 is opened and closed by a gate valve (not shown). Further, since the wafer 24 is transferred to and from the transfer arm 10 at the position facing the transfer port 15 in the recess 24 which is a wafer placement area on the rotary table 2, it is at the transfer position on the lower side of the rotary table 2. In the corresponding part, there are provided lifting pins for passing through the recess 24 and lifting the wafer W from the back surface and its lifting mechanism (both not shown).

  Next, the plasma generator 80 provided as necessary will be described with reference to FIGS. 6 is a schematic cross-sectional view of the plasma generator 80 along the radial direction of the turntable 2, and FIG. 7 is a schematic cross-sectional view of the plasma generator 80 along the direction orthogonal to the radial direction of the turntable 2. FIG. 8 is a top view schematically showing the plasma generator 80. For convenience of illustration, some members are simplified in these drawings.

  Referring to FIG. 6, the plasma generator 80 is made of a high-frequency-transmitting material, has a recess recessed from the upper surface, and a frame member 81 fitted into an opening 11 a formed in the top plate 11, and a frame member 81, a Faraday shielding plate 82 having a substantially box-like shape opened in the upper portion, an insulating plate 83 disposed on the bottom surface of the Faraday shielding plate 82, and supported above the insulating plate 83, And a coiled antenna 85 having a substantially octagonal top surface shape.

  The opening 11a of the top plate 11 has a plurality of steps, and one of the steps is formed with a groove over the entire circumference, and a sealing member 81a such as an O-ring is fitted into the groove. It is. On the other hand, the frame member 81 has a plurality of step portions corresponding to the step portions of the opening portion 11a. When the frame member 81 is fitted into the opening portion 11a, one of the plurality of step portions is provided. The back surface is in contact with the seal member 81a fitted in the groove portion of the opening 11a, whereby the airtightness between the top plate 11 and the frame member 81 is maintained. Further, as shown in FIG. 6, a pressing member 81 c is provided along the outer periphery of the frame member 81 that is fitted into the opening 11 a of the top plate 11, whereby the frame member 81 is pressed downward against the top plate 11. It is done. For this reason, the airtightness between the top plate 11 and the frame member 81 is more reliably maintained.

  The lower surface of the frame member 81 faces the rotary table 2 in the vacuum vessel 1, and a protrusion 81b is provided on the outer periphery of the lower surface so as to protrude downward (toward the rotary table 2) over the entire circumference. ing. The lower surface of the protrusion 81b is close to the surface of the turntable 2, and a space (hereinafter referred to as a third process) is formed above the turntable 2 by the protrusion 81b, the surface of the turntable 2, and the lower surface of the frame member 81. Region P3) is defined. In addition, the space | interval of the lower surface of the projection part 81b and the surface of the turntable 2 may be substantially the same as the height h1 with respect to the upper surface of the turntable 2 of the ceiling surface 11 in the separation space H (FIG. 4).

In addition, the reactive gas nozzle 33 penetrating the protrusion 81b extends in the third processing region P3. In the present embodiment, as shown in FIG. 6, a rare gas supply source 132 filled with a rare gas such as Ar or He is connected to the reaction gas nozzle 33 via a flow rate controller 122 through a pipe 112. In addition, an additive gas supply source 133 that is filled with an additive gas such as O ₂ gas or H ₂ gas is connected by a pipe 112 via a flow rate controller 123. In other words, the rare gas whose flow rate is controlled by the flow rate controller 122 and the additive gas whose flow rate is controlled by the flow rate controller 123 are mixed together at a predetermined flow rate, and the mixed gas is converted into plasma by the plasma generator 80 to be converted into the third state. It is supplied to the processing area P3.

  The reaction gas nozzle 33 is formed with a plurality of discharge holes 35 at predetermined intervals (for example, 10 mm) along the longitudinal direction, and the mixed gas is discharged from the discharge holes 35. As shown in FIG. 7, the discharge hole 35 is inclined from the direction perpendicular to the turntable 2 toward the upstream side in the rotation direction of the turntable 2. Therefore, the gas supplied from the reaction gas nozzle 33 is discharged in the direction opposite to the rotation direction of the turntable 2, specifically, toward the gap between the lower surface of the protrusion 81 b and the surface of the turntable 2. Is done. Accordingly, the reaction gas and the separation gas are prevented from flowing into the third processing region P3 from the space below the ceiling surface 45 located upstream of the plasma generator 80 along the rotation direction of the turntable 2. Is done. Further, as described above, since the protruding portion 81b formed along the outer periphery of the lower surface of the frame member 81 is close to the surface of the turntable 2, the gas in the third processing region P3 is generated by the gas from the reaction gas nozzle 33. The pressure can be easily maintained high. This also prevents the reaction gas and the separation gas from flowing into the third processing region P3.

  Thus, the frame member 81 has a role for separating the third processing region P3 from the second processing region P2. Therefore, the film forming apparatus according to the embodiment of the present invention does not necessarily include the entire plasma generator 80. However, the third processing region P3 is partitioned from the second processing region P2, and the second reaction is performed. In order to prevent gas mixture, it is assumed that a frame member 81 is provided.

  The Faraday shielding plate 82 is made of a conductive material such as metal and is grounded although not shown. As clearly shown in FIG. 8, a plurality of slits 82 s are formed at the bottom of the Faraday shielding plate 82. Each slit 82s extends so as to be substantially orthogonal to a corresponding side of the antenna 85 having a substantially octagonal planar shape.

  Further, as shown in FIGS. 7 and 8, the Faraday shielding plate 82 has support portions 82 a that bend outward at two locations at the upper end. By supporting the support portion 82 a on the upper surface of the frame member 81, the Faraday shielding plate 82 is supported at a predetermined position in the frame member 81.

  The insulating plate 83 is made of, for example, quartz glass, has a size slightly smaller than the bottom surface of the Faraday shielding plate 82, and is placed on the bottom surface of the Faraday shielding plate 82. The insulating plate 83 insulates the Faraday shielding plate 82 and the antenna 85, and transmits the high frequency radiated from the antenna 85 downward.

  The antenna 85 is formed by, for example, winding a copper hollow tube (pipe) in a triple manner so that the planar shape is substantially octagonal. Cooling water can be circulated in the pipe, which prevents the antenna 85 from being heated to a high temperature by the high frequency supplied to the antenna 85. The antenna 85 is provided with a standing portion 85a, and a support portion 85b is attached to the standing portion 85a. The antenna 85 is maintained at a predetermined position in the Faraday shielding plate 82 by the support portion 85b. Further, a high frequency power supply 87 is connected to the support portion 85b via a matching box 86. The high frequency power supply 87 can generate a high frequency having a frequency of 13.56 MHz, for example.

  According to the plasma generator 80 having such a configuration, when high frequency power is supplied from the high frequency power supply 87 to the antenna 85 via the matching box 86, an electromagnetic field is generated by the antenna 85. The electric field component of this electromagnetic field is shielded by the Faraday shielding plate 82 and cannot propagate downward. On the other hand, the magnetic field component propagates into the third processing region P3 through the plurality of slits 82s of the Faraday shielding plate 82. By this magnetic field component, the mixed gas of the rare gas and the additive gas supplied from the reaction gas nozzle 33 to the third processing region P3 at a predetermined flow rate ratio is activated.

  In addition, as shown in FIG. 1, the film forming apparatus according to the present embodiment is provided with a control unit 100 including a computer for controlling the operation of the entire apparatus. A program for causing the film forming apparatus to perform a film forming method to be described later is stored under the control of the control unit 100. This program has a set of steps so as to execute a film forming method to be described later, and is stored in a medium 102 such as a hard disk, a compact disk, a magneto-optical disk, a memory card, a flexible disk, and the like. The data is read into the storage unit 101 and installed in the control unit 100.

  Note that the control unit 100 may also control the rotation speed of the turntable 2. Thereby, the rotational speed of the turntable 2 can be set to the above high-speed rotation of 90-300 rpm or 120-300 rpm.

[Protective film forming method]
Next, the protective film forming method according to the embodiment of the present invention will be described with reference to FIG. FIG. 9 is a diagram for explaining an example of the protective film forming method according to the embodiment of the present invention.

FIG. 9A is a diagram showing an example of the surface pattern of the wafer W used in the protective film forming method according to the present embodiment. In this embodiment, a silicon wafer is used as the wafer W, and a plurality of trenches T are formed in the silicon wafer as shown in FIG. Also, organic amino titanium gas is supplied from the reaction gas nozzle 31, H ₂ O ₂ gas is supplied as the oxidizing gas from the reaction gas nozzle 32, and a mixed gas of Ar gas and O ₂ gas (hereinafter referred to as Ar / O ₂₎ is supplied from the reaction gas nozzle 33. (Referred to as gas).

Hereinafter, the description will focus on the oxidation step. However, since a protective film made of a nitride film can be formed by supplying a nitriding gas from the reaction gas nozzle 32, the case where the nitriding step is performed is also described. To do. When performing the nitriding process, NH ₃ gas is supplied as a nitriding gas from the reaction gas nozzle 32, and a mixed gas of Ar gas and N ₂ gas (hereinafter referred to as Ar / N ₂ gas) is supplied from the reaction gas nozzle 33. It will be.

  Various gases may be used as the organic amino titanium gas used as the Ti precursor, but a typical example is TDAMT (tetradimethylamino titanium). However, in the following description, the type is not particularly limited, and an example using any organic amino titanium gas will be described.

  First, a gate valve (not shown) is opened, and the wafer W is transferred from the outside into the recess 24 of the turntable 2 via the transfer port 15 (FIGS. 2 and 3) by the transfer arm 10 (FIG. 3). This delivery is performed by raising and lowering a lifting pin (not shown) from the bottom side of the vacuum vessel 1 through the through hole on the bottom surface of the recess 24 when the recess 24 stops at a position facing the transport port 15. Such delivery of the wafer W is performed by intermittently rotating the turntable 2, and the wafer W is placed in each of the five recesses 24 of the turntable 2.

Subsequently, after closing the gate valve and evacuating the vacuum vessel 1 to a reachable vacuum level by the vacuum pump 640, the separation gas nozzles 41 and 42 discharge N ₂ gas as separation gas at a predetermined flow rate to supply separation waste. N ₂ gas is also discharged from the pipe 51 and the purge gas supply pipes 72 and 73 at a predetermined flow rate. Along with this, the pressure control means 650 (FIG. 1) controls the inside of the vacuum vessel 1 to a preset processing pressure. Next, the wafer W is heated to, for example, 150 ° C. by the heater unit 7 while rotating the turntable 2 clockwise, for example, at a high rotation speed of 120 rpm.

Thereafter, organic amino titanium gas is supplied from the reactive gas nozzle 31 (FIGS. 2 and 3), and H ₂ O ₂ gas is supplied from the reactive gas nozzle 32. Further, Ar / O ₂ gas is supplied from the reactive gas nozzle 33, and a high frequency having a frequency of 13.56 MHz is supplied to the antenna 85 of the plasma generation source 80 with power of 1400 W, for example. Thus, oxygen plasma is generated in the third processing region P3 between the plasma generation source 80 (FIG. 6) and the turntable 2. In this oxygen plasma, active species such as oxygen ions and oxygen radicals and high energy particles are generated.

Similarly, in the case of the nitriding process, NH ₃ gas is supplied from the reactive gas nozzle 32 and Ar / N ₂ gas is supplied from the reactive gas nozzle 33. Other conditions are similar to the oxidation process. Note that nitrogen plasma is generated in the third processing region P3 between the plasma generation source 80 and the turntable 2. In the nitrogen plasma, active species such as nitrogen ions and nitrogen radicals and high energy particles are generated.

  FIG. 9B is a diagram showing an example of the source gas adsorption process. As the turntable 2 rotates, the wafer W passes through the first processing region P1, the separation region D, the second processing region P2, the third processing region P3, and the separation region D repeatedly in this order (FIG. 3). reference). In the first processing region P1, as shown in FIG. 9B, the organic amino titanium gas molecule Mt is adsorbed on the surface U of the wafer W, and the molecular layer 61 of organic amino titanium is formed. Here, the molecule Mt of the organic aminotitanium gas is an organometallic gas, an organic group is attached around the metal titanium, and the diameter of the molecule Mt is large. Furthermore, since the turntable 2 is rotating at high speed, the organic amino titanium molecule Mt does not reach the back of the trench T and is adsorbed on the surface U of the wafer.

FIGS. 9C and 9D are diagrams showing an example of the oxidation process. As shown in FIG. 9C, after passing through the separation region D, the organic amino titanium gas adsorbed on the surface U of the wafer W is oxidized by the H ₂ O ₂ gas molecules Mo in the second processing region P2. As shown in FIG. 9D, a protective film 62 made of titanium oxide (TiO ₂ ) is formed on the surface U of the wafer W at the upper end of the trench T.

In the case of the nitriding process, FIGS. 9C and 9D show an example of the nitriding step. As shown in FIG. 9C, after passing through the separation region D, the organic amino titanium gas adsorbed on the surface U of the wafer W is oxidized by the NH ₃ gas molecules Mo in the second processing region P2, and FIG. As shown in (d), a protective film 62 made of titanium nitride (TiN) is formed on the surface U of the wafer W at the upper end of the trench T.

  FIG. 9E is a diagram showing an example of a plasma processing (modification processing) step. As shown in FIG. 9E, when the wafer W reaches the third processing region P3 where the plasma generation source 80 is located, the wafer W is exposed to the oxygen plasma PL. Thereby, the oxidation of the protective film 62 is promoted, the film density of the protective film 62 is increased, and the film quality of the protective film 62 is improved.

  FIG. 9F is a diagram showing an example of the source gas adsorption process repeated again. As shown in FIG. 9 (f), when the wafer W reaches the first processing region P <b> 1 again by the rotation of the turntable 2, the organic amino titanium gas molecules Mt supplied from the reaction gas nozzle 31 are changed to the surface of the wafer W. Adsorb to U. At this time, the particle diameter of the organic amino titanium gas molecule Mt is relatively large because the organic group is attached to the titanium, and since the turntable 2 is rotating at high speed, the particle diameter Mt cannot reach the depth of the trench T. Instead, it is adsorbed near the surface of the wafer W.

  Thereafter, while the rotary table 2 continues to rotate at a high speed, the same process is repeated, and a TiO film is deposited on the surface of the wafer W between the trenches T, and a protective film 62 is formed.

  In this way, an organometallic gas having a large molecular diameter is supplied from the reaction gas nozzle 31 as a source gas, and the turntable 2 is rotated at a high speed, so that film formation does not proceed in the trench T, and between the trenches T It is possible to form a local protective film 62 by selectively depositing only in the region. In this embodiment, an example in which organic amino titanium is used as a source gas has been described. However, since an organic metal gas generally has a large molecular diameter, the protection according to this embodiment is performed using other types of organic metal gases. It is also possible to carry out a film forming method. Furthermore, not only an organic metal gas but also an organic metalloid gas such as an organic silane gas has a large molecular diameter, and the protective film forming method according to this embodiment can be carried out.

As described above, since the organic metal gas and the organic metalloid gas generally have a large molecular diameter, the protective film forming method according to this embodiment is performed even when another organic metal gas or organic metalloid gas is used. can do. As the source gas, for example, an organometallic gas used to form a high dielectric film (High-k film) may be used as the source gas, for example, tri (dimethylamino) cyclopentadienyl. A gas such as zirconium (C ₁₁ H ₂₃ N ₃ Zr) may be used. In addition, an organometallic gas obtained by evaporating an organometallic compound containing a metal such as aluminum, hafnium, titanium, or a semimetal such as silane may be used as a source gas.

In general, an organometallic compound used as a source gas for forming a high-k film is a compound containing an amine and contains an amino group (—NH _2, —NHR, —NRR ′). For example, when an organometallic gas reacts with an oxidizing gas and oxidizes, an amino group is eliminated and a harmful gas is generated. In the exhaust pipe detoxification method and film forming apparatus according to the present embodiment, a process of sufficiently oxidizing an amino group and detoxifying a harmful gas is performed, which will be described later. However, the source gas is not limited to the gas described above, and various gases may be used.

  FIG. 10 is a table showing examples of source gases to which the protective film forming method according to the embodiment of the present invention can be applied. As described above, the protective film can be formed using various organometallic gases and organic metalloid gases. Note that FIG. 10 is only an example until the end, and it is possible to carry out the protective film forming method according to the present embodiment using other organic metal gases and organic metalloid gases.

In addition, although the rotational speed of the turntable 2 is set to 90-300 rpm, these also depend on the kind of source gas. For example, when a protective film of TiO ₂ is formed using TDMAT, the rotation speed of the turntable 2 is preferably set to 90 to 240 rpm, and more preferably set to 90 to 120 rpm.

  The rotation speed of the turntable 2 may be set to 120 to 300 rpm, more preferably 120 to 240 rpm, and optimally 180 rpm. In particular, in the case of the nitriding process, a preferable result may be obtained when the rotation speed of the turntable 2 is higher than that of the oxidation process. For example, when forming a TiN protective film using TDMAT, 120 rpm or more May be set at a high speed of, for example, 180 rpm.

  Moreover, when organic metalloid gas, such as organosilane gas, is used for source gas, it is preferable that the rotational speed of the turntable 2 is set to a high speed rather than the case where organic metal gas is used for source gas. For example, when an organic metalloid gas such as an organic silane gas is used as the raw material gas, the rotation speed of the turntable 2 is preferably set to 150 to 300 rpm, and more preferably set to 180 to 300 rpm.

  The rotation speed of the turntable 2 may be appropriately set within a range of 90 rpm or more according to the raw material gas, the opening width of trenches T formed on the surface of the wafer W, holes, and the like. At present, since the mechanical limit of the rotation speed of the turntable 2 is 300 rpm, the upper limit of 300 rpm has been described. However, the turntable 22 can be rotated at a speed higher than 300 rpm, for example, 400 rpm and 500 rpm. If so, the rotational speed of the turntable 2 may be set at a higher speed.

  Further, the pattern formed on the surface of the wafer W may be a pattern in which a plurality of holes are formed in addition to the trench, or a pattern in which both the trench and the hole are formed together. In this region, the protective film 62 can be formed.

  In the above-described embodiment, an example in which thermal oxidation treatment is performed in the oxidation step and then a plasma treatment (modification treatment) step is described. However, the plasma treatment step is not essential, and only the thermal oxidation treatment is performed. Good. In this case. What is necessary is just to omit the process of FIG.9 (e).

  Similarly, also in the nitriding process, the thermal nitriding process may be performed in the nitriding process, and then the plasma process (modifying process) may be performed, or the process of FIG. Good.

  Further, only the plasma treatment process may be performed without performing the thermal oxidation process, and the oxidation process and the reforming process may be combined. In this case, in the step of FIG. 9B, the plasma PL shown in FIG. 9E is generated to perform the oxidation treatment.

  Similarly, in the nitriding process, only the plasma treatment process may be performed without performing the thermal nitridation process, and the nitriding process and the reforming process may be combined. In this case, in the step of FIG. 9B, the plasma PL shown in FIG. 9E is generated to perform nitriding.

  Thus, various selections are possible for the oxidation step and the plasma treatment step depending on the application.

  Similarly, various selections are possible for the nitriding step and the plasma step in the nitriding process depending on the application.

  In the present embodiment, an example of a method for forming a protective film by a film forming apparatus using the turntable 2 has been described. However, if the gas supply can be switched at high speed, the present embodiment can be used without using the turntable 2. It is possible to carry out the protective film forming method according to the embodiment. In this case, since a series of steps are performed once every time the turntable 2 makes one rotation, a series of raw material adsorption step, oxidation step, plasma treatment step, and purge between the raw material adsorption step and the oxidation step are performed in one rotation. The purge process between the process, the plasma treatment process, and the raw material adsorption process is performed once. In the case of 120 rpm, 120 cycles may be performed per minute, and in the case of 90 rpm, conversion may be performed assuming that 90 cycles are performed per minute.

  Similarly, in the case of the nitriding process, when the turntable 2 rotates once, a series of raw material adsorption steps, nitriding steps, plasma processing steps, a purge step between the raw material adsorption steps and the nitriding steps, plasma processing steps and raw materials are performed. The purge process between the adsorption process and the adsorption process is performed once. In this case as well, conversion may be performed assuming that 120 cycles are performed in 120 minutes for 120 rpm, and 90 cycles are performed in 1 minute for 90 rpm.

[Example]
Next, examples in which the present invention is implemented will be described.

  FIG. 11 is a diagram illustrating an implementation result of the protective film forming method according to the example of the present invention, together with an implementation result of the protective film forming method according to the comparative example.

FIGS. 11A and 11B are diagrams showing the results of carrying out the protective film forming method according to the comparative example. Specifically, TDMAT was used as the source gas, and H ₂ O ₂ was used as the oxidizing gas. The plasma generator 80 was not used. The temperature of the wafer was set to 150 ° C. The trench opening width was 50 nm.

  FIG. 11A is a diagram showing an implementation result of the protective film forming method according to Comparative Example 1 in which the rotation speed of the turntable 2 is 30 rpm. As shown in FIG. 11A, in Comparative Example 1, it is shown that the film is also formed inside the trench, and the protective film cannot be locally formed.

  FIG. 11B is a diagram showing an implementation result of the protective film forming method according to Comparative Example 2 in which the rotation speed of the turntable 2 is 30 rpm. As shown in FIG. 11B, in Comparative Example 2, as in Comparative Example 1 in FIG. 11A, a film is also formed inside the trench, and a protective film can be locally formed. Not shown.

  FIG. 11C is a diagram showing an implementation result of the protective film forming method according to Example 1 in which the rotation speed of the turntable 2 is 90 rpm. As shown in FIG. 11C, it is shown that the film is not formed so much in the trenches, but only on the surface of the wafer between the trenches, and a protective film is formed in a mushroom shape. Has been.

  FIG. 11 (d) is a diagram showing an implementation result of the protective film forming method according to Example 2 in which the rotation speed of the turntable 2 is 120 rpm. As shown in FIG. 11 (d), film formation is hardly performed inside the trench, film formation is performed only on the surface of the wafer between the trenches, and protection is provided in a cap shape only where a protective film is required. It is shown that a film is formed. Thus, it is shown that a protective film can be formed more selectively and locally at 120 rpm than 90 rpm, that is, at a higher rotation speed.

  FIG. 12 is a diagram illustrating an implementation result of the protective film forming method according to the third embodiment. In Example 3, the rotation speed of the turntable 2 was set to 120 rpm, and the passage of time for forming the protective film was observed when the plasma generator 80 was used.

  12A shows 0 seconds from the start of film formation, FIG. 12B shows 180 seconds from the start of film formation, FIG. 12C shows 240 seconds from the start of film formation, and FIG. 12D shows 300 seconds from the start of film formation. FIG. 12E shows the film formation state after 360 seconds from the start of film formation.

  As shown in FIGS. 12A to 12E, even when time has elapsed, the film formation inside the trench does not increase in thickness, and the wafer surface area between the trenches does not increase. Only film formation is growing. As described above, the results of Example 3 show how the protective film forming method of the present invention is an excellent method for selectively forming a protective film.

FIG. 13 is a diagram showing an implementation result of the protective film forming method according to Comparative Examples 3 and 4. In Comparative Examples 3 and 4, film formation was performed using TiCl ₄ as a source gas and changing the rotation speed of the turntable 2. TiCl ₄ is a Ti-containing gas that is not an organometallic gas, and its molecular diameter is considerably smaller than that of an organometallic gas.

FIG. 13A is a diagram showing an implementation result of the protective film forming method according to Comparative Example 3. In Comparative Example 3, TiCl ₄ was used as the source gas, and the rotation speed of the turntable 2 was set to a high speed of 120 rpm. In this case, as shown in FIG. 13A, a film was formed inside the trench, and a selective protective film was not formed.

FIG. 13B is a diagram showing an implementation result of the protective film forming method according to Comparative Example 4. In Comparative Example 3, TiCl ₄ was used as the source gas, and the rotation speed of the turntable 2 was set to a low speed of 30 rpm. Also in this case, as shown in FIG. 13B, a film was formed inside the trench, and a selective protective film was not formed.

  Thus, in order to implement the protective film formation method concerning embodiment of this invention, it turns out that it is necessary to use organometallic gas or organic semi-metal gas as source gas.

  FIG. 14 is a diagram showing an implementation result of the protective film formation method according to Example 4. In Example 4, after forming the protective film, wet etching was performed, and the processed protective film was observed.

  FIG. 14A is a diagram showing a state in which a protective film is formed by film formation. On the other hand, FIG. 14B is a diagram showing a state after wet etching is performed on the protective film from the state of FIG. As shown in FIG. By performing wet etching, the size of the protective film can be reduced, and the protective film can be provided only in a region that needs protection.

  On the other hand, the state of FIG. 14A is a state in which an air gap whose upper surface is closed is formed, and if there is a demand for the formation of such an air gap in the future, It can be applied as a gap forming method.

  As described above, according to the method for forming a protective film according to the embodiment of the present invention, not only the formation of the protective film but also applications in various future fields that require local film formation are possible. .

  FIG. 15 is a diagram illustrating an implementation result of the protective film forming method according to the fifth embodiment. In Example 5, a TiN film was formed on the trench gap using TDMAT by a nitriding process.

As process conditions, the opening width of the trench was 44 nm, and the pressure in the vacuum vessel 1 was set to 1.4 to 1.8 Torr. The source gas was TDMAT, and the nitriding gas was NH ₃ . The temperature of the wafer W was set to 200 ° C., and the rotation speed of the turntable 2 was set to 180 rpm. The film was formed for 7 to 10 minutes, and the film was formed to a film thickness of 39.60 nm.

  As a result, as shown in FIG. 15, a cap-shaped protective film made of a TiN film was formed on the upper end, and the thickness of the protective film was 23.8 nm. Thus, it was shown that a protective film can also be formed by a nitride film.

  The preferred embodiments and examples of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments and examples, and the above-described embodiments and examples can be performed without departing from the scope of the present invention. Various modifications and substitutions can be made to the embodiments.

DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Rotary table 7 Heater unit 11 Top plate 12 Container body 15 Conveying port 24 Recessed part 31-33 Reaction gas nozzle 41, 42 Separation gas nozzle 80 Plasma generator 130-132 Gas supply source P1-P3 Processing area W Wafer T Trench

Claims (23)

A method for forming a protective film, wherein a plurality of depression shapes are formed on a surface of a substrate, and a protective film is formed on the surface of a non-dent formation area between the plurality of depression shapes adjacent to each other,
A source gas adsorption step of supplying a source gas composed of an organic metal gas or an organic metalloid gas onto the surface of the substrate including the plurality of recess shapes, and adsorbing the source gas on the surface of the substrate;
An oxidizing gas is supplied onto the surface of the substrate including the plurality of depressions, the source gas adsorbed on the surface of the substrate is oxidized, and an organic metal or organic metalloid oxide film contained in the source gas is formed. An oxidation step of forming a film,
The method for forming a protective film, wherein the source gas adsorption step and the oxidation step are repeatedly performed at a repetition cycle of 90 to 300 times per minute. The protective film forming method according to claim 1, wherein the oxidizing gas is H ₂ O, H ₂ O ₂ , O _2, or O ₃ , and the source gas is oxidized by thermal oxidation.   3. The reforming step of supplying a rare gas and an additive gas converted into plasma to the oxide film of the organic metal or the organic metalloid between the oxidation step and the source gas adsorption step. The protective film formation method of description.   The method for forming a protective film according to claim 1, wherein, in the oxidation step, the oxidizing gas converted into plasma is supplied. The substrate is disposed along a circumferential direction on a rotary table provided in the processing chamber,
A source gas supply region capable of supplying the source gas onto the surface of the substrate along the circumferential direction of the rotary table, and an oxidizing gas capable of supplying the oxidizing gas onto the surface of the substrate. Supply areas are provided spaced apart from one another,
By rotating the rotary table at a rotation speed of 90 to 300 rpm and sequentially passing the source gas supply region and the oxidizing gas supply region through the substrate, the source gas adsorption step and the oxidation step are performed 90 times per minute. The method for forming a protective film according to any one of claims 1 to 4, wherein the method is performed at a repeating cycle of 300 times or less. The substrate is disposed along a circumferential direction on a rotary table provided in the processing chamber,
A source gas supply region capable of supplying the source gas onto the surface of the substrate along the rotation direction of the rotary table, and an oxidizing gas supply capable of supplying the oxidizing gas onto the surface of the substrate. A plasma gas supply region capable of supplying the region and the plasmad rare gas and additive gas onto the surface of the substrate are provided apart from each other;
The source gas adsorption step and the oxidation step are performed by rotating the rotary table at a rotation speed of 90 to 300 rpm and sequentially passing the source gas supply region, the oxidizing gas supply region, and the plasma gas supply region through the substrate. The protective film forming method according to claim 3, wherein the reforming step is performed at a repetition cycle of 90 to 300 times per minute. The substrate is disposed along a circumferential direction on a rotary table provided in the processing chamber,
A source gas supply region in which the source gas can be supplied onto the surface of the substrate along the direction of rotation of the rotary table, and the plasmad oxidizing gas is supplied onto the surface of the substrate. Possible plasma gas supply regions are provided spaced apart from each other;
By rotating the rotary table at a rotation speed of 90 to 300 rpm and sequentially passing the source gas supply region and the plasma gas supply region through the substrate, the source gas adsorption step and the oxidation step are performed 90 times per minute. The method for forming a protective film according to claim 4, which is performed at a repetition cycle of 300 times or less. A method for forming a protective film, wherein a plurality of depression shapes are formed on a surface of a substrate, and a protective film is formed on the surface of a non-dent formation area between the plurality of depression shapes adjacent to each other,
A source gas adsorption step of supplying a source gas composed of an organic metal gas or an organic metalloid gas onto the surface of the substrate including the plurality of recess shapes, and adsorbing the source gas on the surface of the substrate;
A nitriding gas is supplied onto the surface of the substrate including the plurality of depressions, the source gas adsorbed on the surface of the substrate is oxidized, and an organic metal or organic metalloid nitride film contained in the source gas is formed. A nitriding step for forming a film,
The method for forming a protective film, wherein the source gas adsorption step and the nitriding step are repeatedly performed at a repetition cycle of 90 to 300 times per minute. The protective film forming method according to claim 8, wherein the nitriding gas is an NH ₃ -containing gas, and the source gas is nitrided by thermal nitriding.   10. The reforming step of supplying a rare gas and an additive gas converted into plasma to the nitride film of the organic metal or the organic metalloid between the nitriding step and the source gas adsorption step. The protective film formation method of description. The protective film forming method according to claim 8, wherein in the nitriding step, plasmaized NH ₃ -containing gas or N ₂ -containing gas is supplied. The substrate is disposed along a circumferential direction on a rotary table provided in the processing chamber,
A source gas supply region capable of supplying the source gas onto the surface of the substrate along the circumferential direction of the turntable and a nitriding gas capable of supplying the nitriding gas onto the surface of the substrate above the turntable Supply areas are provided spaced apart from one another,
The raw gas adsorption process and the nitriding process are performed 90 times per minute by rotating the rotary table at a rotational speed of 90 to 300 rpm and sequentially passing the raw material gas supply area and the nitriding gas supply area through the substrate. The method for forming a protective film according to any one of claims 8 to 11, which is performed at a repetition cycle of 300 times or less. The substrate is disposed along a circumferential direction on a rotary table provided in the processing chamber,
A source gas supply region capable of supplying the source gas onto the surface of the substrate along the rotation direction of the rotary table, and a nitriding gas supply capable of supplying the nitriding gas onto the surface of the substrate. A plasma gas supply region capable of supplying the region and the plasmad rare gas and additive gas onto the surface of the substrate are provided apart from each other;
The source gas adsorption step and the nitridation step are performed by rotating the rotary table at a rotational speed of 90 to 300 rpm and sequentially passing the source gas supply region, the nitriding gas supply region, and the plasma gas supply region through the substrate. The protective film forming method according to claim 10, wherein the reforming step is performed at a repetition cycle of 90 to 300 times per minute. The substrate is disposed along a circumferential direction on a rotary table provided in the processing chamber,
A source gas supply region in which the source gas can be supplied onto the surface of the substrate along the rotation direction of the rotary table, and the plasmad nitriding gas is supplied onto the surface of the substrate above the rotary table. Possible plasma gas supply regions are provided spaced apart from each other;
By rotating the rotary table at a rotation speed of 90 to 300 rpm and sequentially passing the source gas supply region and the plasma gas supply region through the substrate, the source gas adsorption step and the nitridation step are performed 90 times per minute. The method for forming a protective film according to claim 11, which is performed at a repeating cycle of 300 times or less.   The protective film forming method according to claim 5, wherein the rotary table is rotated at a rotation speed of 90 to 240 rpm.   The protective film forming method according to claim 15, wherein the rotary table is rotated at a rotation speed of 90 to 120 rpm.   The protective film forming method according to claim 5, wherein the rotary table is rotated at a rotational speed of 150 to 300 rpm.   The protective film forming method according to claim 17, wherein the turntable is rotated at a rotation speed of 180 to 300 rpm.   The protective film forming method according to claim 1, wherein the organometallic gas is a gas capable of forming a high-k film.   The method of forming a protective film according to claim 1, wherein the organometallic gas is a gas containing organic amino titanium.   The method for forming a protective film according to claim 20, wherein the gas containing organic aminotitanium is a gas containing tetrakisdimethylaminotitanium.   The method for forming a protective film according to claim 1, wherein the organic metalloid gas is an organosilane gas.   The method for forming a protective film according to claim 1, wherein the hollow shape is a trench.