JP2022147091A - Film deposition apparatus and film deposition method - Google Patents

Abstract

To provide a film deposition apparatus and film deposition method, capable of efficiently achieving film deposition by ALD and film deposition by CVD with a low footprint.SOLUTION: A film deposition apparatus including: a treatment vessel; a mounting table for mounting a substrate; an ALD gas supply part; a CVD gas supply part; a showerhead; a heating part for heating the substrate; and an exhaust part for exhausting the inside of the treatment vessel, can perform film deposition by ALD and film deposition by CVD. The showerhead includes: a first gas diffusion chamber having a supplied ALD gas; a second gas diffusion chamber having a supplied CVD gas; a first gas discharge hole for discharging the ALD gas from the first gas diffusion chamber; and a second gas discharge hole for discharging the CVD gas from the second gas diffusion chamber, and the conductance of the first gas discharge hole is larger than that of the second gas discharge hole.SELECTED DRAWING: Figure 1

Description

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

Various films are formed in the manufacturing process of semiconductor devices. As a method for producing such a film, there is an atomic layer deposition method in which a raw material gas and a reaction gas are alternately supplied to a processing container in which a substrate is arranged, with a surplus gas being purged therebetween, to form a film. ; ALD) are known. Patent Document 1 describes a film forming apparatus for forming a TiN film by ALD.

ALD differs from chemical vapor deposition (CVD) in which a processing gas is collectively supplied into a processing chamber to form a film on a substrate, and gas supply conditions and the like are required. Therefore, an ALD film forming apparatus is designed differently from a CVD film forming apparatus.

JP 2015-78418 A

The present disclosure provides a film formation apparatus and a film formation method that can efficiently realize film formation by ALD and film formation by CVD with a small footprint.

A film forming apparatus according to an aspect of the present disclosure includes a processing container in which a substrate is accommodated, a mounting table on which the substrate is placed in the processing container, and an ALD gas for supplying an ALD gas used for film formation by ALD. a supply unit, a CVD gas supply unit for supplying a CVD gas used for film formation by CVD, the ALD gas and the CVD gas are supplied, and the ALD gas and the CVD gas are supplied to the processing container. A shower head that discharges air, a heating unit that heats the substrate on the mounting table, and an exhaust unit that exhausts the inside of the processing container, and performs film formation by ALD and film formation by CVD on the substrate on the mounting table. The showerhead includes a first gas diffusion chamber to which the ALD gas is supplied, a second gas diffusion chamber to which the CVD gas is supplied, and the first gas diffusion chamber. and a second gas ejection hole for ejecting the CVD gas from the second gas diffusion chamber, wherein the conductance of the first gas ejection hole is the It is larger than the conductance of the second gas discharge hole.

ADVANTAGE OF THE INVENTION According to this disclosure, the film-forming apparatus and film-forming method which can implement|achieve film-forming by ALD and film-forming by CVD efficiently with a small footprint are provided.

1 is a cross-sectional view showing a film forming apparatus according to one embodiment; FIG. 2 is an enlarged cross-sectional view showing a shower head portion in the film forming apparatus of FIG. 1; FIG. FIG. 2 is a bottom view schematically showing the arrangement of gas ejection holes on the bottom surface of the shower head in the film forming apparatus of FIG. 1; FIG. 4 is a diagram showing the relationship between the film thickness and the surface roughness Sa when a B-SiGe film is actually formed on a TiN film; BRIEF DESCRIPTION OF THE DRAWINGS It is a horizontal cross-sectional view which shows roughly an example of the processing system which mounts the film-forming apparatus of one Embodiment.

Embodiments will be described below with reference to the accompanying drawings.

<Deposition equipment>
FIG. 1 is a cross-sectional view showing a film forming apparatus according to one embodiment.
The film forming apparatus 100 of this embodiment is configured as an apparatus capable of performing both ALD and CVD on a substrate, and forms a titanium nitride film (TiN film) by ALD and a boron-doped silicon-germanium film by CVD. A case of forming a film (B-SiGe) film will be described as an example.

The film forming apparatus 100 has a chamber 1 which is a processing container, a susceptor (substrate mounting table) 2 , a shower head 3 , an exhaust section 4 , a gas supply section 5 and a control section 6 .

The chamber 1 is made of metal such as aluminum and has a substantially cylindrical shape. A loading/unloading port 11 for loading/unloading a semiconductor wafer (hereinafter simply referred to as a wafer), which is a substrate, is formed in the side wall of the chamber 1 , and the loading/unloading port 11 can be opened and closed by a gate valve 12 . An annular exhaust duct 13 having a rectangular cross section is provided on the main body of the chamber 1 . A slit 13 a is formed along the inner peripheral surface of the exhaust duct 13 . An exhaust port 13b is formed in the outer wall of the exhaust duct 13. As shown in FIG. A ceiling wall 14 is provided on the upper surface of the exhaust duct 13 so as to block the upper opening of the chamber 1 . A sealing ring 15 hermetically seals between the ceiling wall 14 and the exhaust duct 13 .

The susceptor 2 is for mounting a wafer W as a substrate in the chamber 1, and is shaped like a disk having a size corresponding to the wafer W and is provided horizontally. Susceptor 2 is supported by support member 23 . A heater 21 for heating the wafer W is embedded inside the susceptor 2 . The heater 21 is powered by a heater power supply (not shown) to generate heat. By controlling the output of the heater 21, the temperature of the wafer W is controlled to a predetermined temperature. The susceptor 2 is provided with a cover member 22 made of ceramics so as to cover the outer peripheral region of the wafer mounting surface and the side surfaces.

A support member 23 that supports the susceptor 2 extends downward from the chamber 1 through a hole formed in the bottom wall of the chamber 1 from the center of the bottom surface of the susceptor 2, and its lower end is connected to an elevating mechanism 24. An elevating mechanism 24 allows the susceptor 2 to move up and down via the support member 23 between the processing position shown in FIG. The processing position of the susceptor 2 may be different between ALD film formation and CVD film formation. When forming a film by ALD, the susceptor 2 is preferably close to the shower head 3 from the viewpoint of increasing the amount of gas exposed to the wafer W. When forming a film by CVD, from the viewpoint of ensuring gas uniformity. , the susceptor 2 is preferably further away from the showerhead 3 than in ALD.

A collar portion 25 is attached to the support member 23 at a position below the chamber 1 . A bellows 26 is provided that expands and contracts as it moves up and down.

Three wafer support pins 27 (only two are shown) are provided in the vicinity of the bottom surface of the chamber 1 so as to protrude upward from an elevating plate 27a. The wafer support pins 27 can be moved up and down via an elevating plate 27a by a pin elevating mechanism 28 provided below the chamber 1. The wafer support pins 27 are inserted through the through holes 2a provided in the susceptor 2 at the transfer position, thereby lifting the susceptor. It is possible to project and sink against the upper surface of 2. As a result, the wafer W is transferred between the wafer transfer mechanism (not shown) and the susceptor 2 .

The shower head 3 is for supplying the processing gas into the chamber 1 in the form of a shower. . A processing space S is formed between the shower head 3 and the susceptor 2 while the susceptor 2 is in the processing position. A detailed structure of the shower head 3 will be described later.

The exhaust section 4 has an exhaust pipe 41 connected to the exhaust port 13 b of the exhaust duct 13 , an automatic pressure control valve (APC) 42 connected to the exhaust pipe 41 , and a vacuum pump 43 . During processing, the gas in the chamber 1 reaches the exhaust duct 13 through the slit 13 a and is exhausted from the exhaust duct 13 through the exhaust pipe 41 by the vacuum pump 43 .

The gas supply unit 5 has an ALD gas supply unit 501 and a CVD gas supply unit 502, and supplies gases used for ALD and CVD to the processing space S in the chamber 1 through the gas block 53 and the shower head 3. supply. The configuration of the gas supply unit 5 will be described later in detail.

The control unit 6 is composed of a computer, and includes a main control unit having a CPU, an input device (keyboard, mouse, etc.), an output device (printer, etc.), a display device (display, etc.), and a storage device (storage medium). have. The main control unit controls each component constituting the film forming apparatus, such as an on-off valve, a flow controller, an automatic pressure control valve, and a heater. These operations are controlled by a processing recipe, which is a control program stored in a storage medium (hard disk, optical disk, semiconductor memory, etc.) built into the storage device.

[Gas supply part]
As described above, the gas supply section 5 has the ALD gas supply section 501 and the CVD gas supply section 502 .

The ALD gas supply unit 501 includes a TiCl ₄ gas supply source 511, an NH ₃ gas supply source 512, an additive gas supply source 513, a first Ar gas supply source 514, a second Ar gas supply source 515, and a third Ar gas. source 516; A TiCl ₄ gas supply source 511 supplies TiCl ₄ gas as a raw material gas. The NH ₃ gas supply source 512 supplies NH ₃ gas, which is a nitriding gas (reactive gas). The additive gas supply source 513 supplies the additive gas X. As shown in FIG. Examples of additive gases include gases for improving the film quality of the TiN film such as H2 gas, and Si _- containing gases such as _SiH4 gas and dichlorosilane gas for containing Si in the TiN film. The first to third Ar gas supply sources 514, 515, 516 supply Ar gas as purge gas.

In addition, the ALD gas supply unit 501 includes a TiCl ₄ gas pipe 521, an NH ₃ gas pipe 522, an additive gas pipe 523, a first Ar gas pipe 524, a second Ar gas pipe 525, and a third Ar gas pipe 526. have

One end of the _TiCl4 gas pipe 521 is connected to the _TiCl4 gas supply source 511, one end of the _NH3 gas pipe 522 is connected to the _NH3 gas supply source 512, and one end of the additive gas pipe 523 is connected to the additive gas supply source 513. It is The other end of the TiCl ₄ gas pipe 521, the other end of the NH ₃ gas pipe 522, and the other end of the additive gas pipe 523 are connected to the first gas junction 51, and the TiCl ₄ gas, the NH ₃ gas, and the additive gas are connected to the first gas junction 51. They are merged at the one-gas merging section 51 . One ends of the first Ar gas pipe 524, the second Ar gas pipe 525, and the third Ar gas pipe 526 are connected to the first Ar gas supply source 514, the second Ar gas supply source 515, and the third Ar gas supply source 516, respectively. The other ends of these are connected to a TiCl ₄ gas pipe 521, an NH ₃ gas pipe 522, and an additive gas pipe 523, respectively.

A valve 541, a gas storage tank 537, and a flow rate controller 531 are interposed in the TiCl ₄ gas pipe 521 in this order from the downstream side. A valve 542, a gas storage tank 538, and a flow rate controller 532 are interposed in the NH ₃ gas pipe 522 in this order from the downstream side. A valve 543, a gas storage tank 539, and a flow rate controller 533 are interposed in the additive gas pipe 523 in this order from the downstream side. Valves 544, 545, 546 and flow rate controllers 534, 535, 536 are respectively installed in the first to third Ar gas pipes 524, 525, 526 from the downstream side.

The valves 541 to 546 are for cutting off gas to the chamber 1 during the ALD process, and are composed of high-speed valves that can be opened and closed at high speed. Mass flow controllers, for example, can be used as the flow rate controllers 531-536. The gas storage tanks 537, 538, and 539 temporarily store the gas supplied from the gas supply source connected to the corresponding pipe before supplying it into the chamber 1. After pressurizing the inside to a predetermined pressure, each gas is discharged from each gas storage tank into the chamber 1 . Thereby, a large flow rate of gas can be supplied to the wafer W stably.

From the first gas confluence portion 51, a first gas flow path 54 extends to the shower head 3 through the gas block 53 and the ceiling wall 14, and the ALD gas flows from the shower head 3 to the processing space S as described later. Dispensed.

In the ALD gas supply unit 501, if no additive gas is required, the additive gas supply source 513 and the additive gas pipe 523 may not be provided.

Note that the raw material gas is not limited to TiCl ₄ gas, and other Ti-containing gas such as tetra(isopropoxy)titanium (TTIP) may be used. Also, the nitriding gas (reactive gas) is not limited to _NH3 gas, and other N-containing gas such as monomethylhydrazine (MMH) may be used. Furthermore, the purge gas is not limited to Ar gas, and other inert gas may be used.

The CVD gas supply unit 502 includes a B ₂ H ₆ gas supply source 551, a SiH ₄ gas supply source 552, a GeH ₄ gas supply source 553, a fourth Ar gas supply source 554, a fifth Ar gas supply source 555, and a sixth Ar gas supply source 556 . A B ₂ H ₆ gas supply source 551 supplies B ₂ H ₆ gas, which is a B-containing gas. SiH ₄ gas supply source 552 supplies SiH ₄ gas, which is a Si-containing gas. A GeH ₄ gas supply source 553 supplies GeH ₄ gas, which is a Ge-containing gas. The fourth to sixth Ar gas supply sources 554, 555, 556 supply Ar gas as purge gas.

In addition, the CVD gas supply unit 502 includes a B ₂ H ₆ gas pipe 561, a SiH ₄ gas pipe 562, a GeH ₄ gas pipe 563, a fourth Ar gas pipe 564, a fifth Ar gas pipe 565, and a sixth Ar gas pipe. and a pipe 566 .

One end of _B2H6 gas pipe 561 is connected to _B2H6 gas supply source 551, _one end of _SiH4 gas pipe 562 is connected to _SiH4 gas supply source 552, and one end of _GeH4 gas pipe 563 is connected to _GeH4 gas supply source ₅₅₂ . It is connected to a gas supply source 553 . In addition, the other end of the B ₂ H ₆ gas pipe 561, the other end of the SiH ₄ gas pipe 562, and the other end of the GeH ₄ gas pipe 563 are connected to the second gas junction 52 to supply the B ₂ H ₆ gas and the SiH ₄ gas. , GeH ₄ gas are merged in the second gas junction 52 . One ends of the fourth Ar gas pipe 564, the fifth Ar gas pipe 565, and the sixth Ar gas pipe 566 are connected to the fourth Ar gas supply source 554, the fifth Ar gas supply source 555, and the sixth Ar gas supply source 556, respectively. The other ends of these are connected to a B ₂ H ₆ gas pipe 561, a SiH ₄ gas pipe 562, and a GeH ₄ gas pipe 563, respectively.

A valve 581, a gas storage tank 577, and a flow rate controller 571 are interposed in the B ₂ H ₆ gas pipe 561 in order from the downstream side. A valve 582 , a gas storage tank 578 , and a flow rate controller 572 are interposed in the SiH ₄ gas pipe 562 in this order from the downstream side. A valve 583, a gas storage tank 579, and a flow rate controller 573 are interposed in the GeH ₄ gas pipe 563 in this order from the downstream side. Valves 584, 585, 586 and flow rate controllers 574, 575, 576 are respectively installed in the fourth to sixth Ar gas pipes 564, 565, 566 from the downstream side.

The valves 581 to 586 are for cutting off each gas to the chamber 1 during the CVD process. Since high-speed gas switching is not performed in CVD unlike ALD, high-speed valves are not required as the valves 581-586. Mass flow controllers, for example, can be used as the flow rate controllers 571-576. Further, the gas storage tanks 577, 578, and 579 are not essential for the CVD process, but as will be described later, when forming a B—SiGe film, sufficient gas is supplied at the initial stage of film formation. It may be provided from the viewpoint of improving the morphology of the surface.

From the second gas confluence portion 52, a second gas flow path 55 extends to the shower head 3 via the gas block 53 and the ceiling wall 14, and the CVD gas flows from the shower head 3 to the processing space S as described later. Dispensed.

Each pipe of the ALD gas supply unit 501 and the CVD gas supply unit 502 is provided with other valves (not shown), for example, before and after the flow rate controller.

Note that the B-containing gas is not limited to the B ₂ H ₆ gas, and other B-containing gases such as boron trichloride (BCl ₃ ) gas, alkylborane gas, and decaborane gas may be used. Examples of the alkylborane gas include trimethylborane (B(CH ₃ ) ₃ ) gas, triethylborane (B(C ₂ H ₅ ) ₃ ) gas, B(R ₁ )(R ₂ )(R ₃ ), B(R ₁ ) Gases represented by (R ₂ )H, B(R ₁ )H2 (R ₁ , R ₂ and R ₃ are alkyl groups) and the like can be used. Further, the Si _- containing gas is not limited to _SiH4 gas, and disilane ( _Si2H6 ), trisilane ( _Si3H8 ), _tetrasilane ( _Si4H10 ), pentasilane ( _Si5H12 ), _{hexasilane ( Si6} H ₁₄ ), heptasilane (Si ₇ H ₁₆ ), cyclotrisilane (Si ₃ H ₆ ), cyclotetrasilane (Si ₄ H ₈ ), cyclopentasilane (Si ₅ H ₁₀ ), cyclohexasilane (Si ₆ H ₁₂ ). , cycloheptasilane (Si ₇ H ₁₄ ) may also be used. Furthermore, the Ge-containing gas is not limited to GeH ₄ gas, and other Ge-containing gases such as digermane (Ge ₂ H ₆ ) or aminogermane gas may be used. Furthermore, the purge gas is not limited to Ar gas, and other inert gas may be used.

[shower head]
Next, the shower head 3 will be explained.
FIG. 2 is a cross-sectional view showing an enlarged view of the shower head 3 in the film forming apparatus of FIG. 1, and FIG. 3 is a bottom view showing an outline of the arrangement of gas discharge holes on the bottom of the shower head.

The showerhead 3 has an upper plate 31 , an intermediate plate 32 and a lower plate 33 . A first gas diffusion space 34 is formed between the intermediate plate 32 and the lower plate 33 , and a second gas diffusion space 35 is formed between the upper plate 31 and the intermediate plate 32 .

A first gas flow path 54 extending through the gas block 53 and the ceiling wall 14 from the first gas confluence portion 51 where the ALD gas merges further passes through the upper plate 31 and the intermediate plate 32 to the first gas diffusion chamber 34 . has reached A plurality of first gas discharge holes 36 opening to the chamber 1 are formed so as to penetrate the lower plate 33 from the first gas diffusion chamber 34 .

On the other hand, a second gas flow path 55 extending through the gas block 53 and the ceiling wall 14 from the second gas junction 52 where the CVD gases join reaches the second gas diffusion chamber 35 through the upper plate 31 . ing. A plurality of second gas discharge holes 37 opening into the processing container 1 are formed so as to extend from the second gas diffusion chamber 35 through the portion of the intermediate plate 32 below the second gas diffusion chamber 35 and the lower plate 33 . formed.

That is, the first gas flow path 54, the first gas diffusion chamber 34, and the first gas discharge hole 36 constitute the gas path for ALD, and the second gas flow path 55, the second gas diffusion chamber 35, and the second gas discharge A hole 37 constitutes a CVD gas path.

As described above, the shower head 3 has a matrix structure in which the ALD gas and the CVD gas are supplied through separate systems, pass through separate gas diffusion chambers, and are discharged from separate gas discharge holes.

The shower head 3 is configured such that the conductance of the first gas ejection holes 36 for ejecting the ALD gas is higher than the conductance of the second gas ejection holes 37 for ejecting the CVD gas. This is because it is desirable to discharge a large amount of gas to the wafer W in a short period of time in the case of ALD, whereas it is desirable to discharge the gas uniformly to the wafer W in the case of CVD. be. That is, the conductance of the first gas ejection holes 36 for ejecting the ALD gas is increased to increase the amount of gas ejection, and the conductance of the second gas ejection holes 37 for ejecting the CVD gas is decreased to increase the amount of gas ejection. It is designed to promote gas diffusion in the

The conductance can be adjusted, for example, by the diameter of the gas ejection holes. In this example, the diameter of the first gas ejection hole 36 for ejecting the ALD gas is made larger than the diameter of the second gas ejection hole 37 for ejecting the CVD gas to adjust the conductance. The diameter of the first gas injection hole 36 for ALD can be 1.2 to 2.0 mm, and the diameter of the second gas injection hole 37 for CVD can be 0.3 to 1.0 mm.

Also, the conductance can be adjusted by, for example, the number of gas ejection holes. That is, the conductance may be adjusted by increasing the number of the first gas ejection holes 36 for ejecting the ALD gas more than the number of the second gas ejection holes 37 for ejecting the CVD gas.

Further, in this example, the first gas ejection holes 36 and the second gas ejection holes 37 are arranged concentrically. As a result, the gas can be uniformly supplied to the wafer W in the concentric direction.

In this example, the first gas diffusion chamber 34 to which the ALD gas is supplied is provided below the second gas diffusion chamber 35 to which the CVD gas is supplied, that is, on the susceptor 2 side. This is because CVD is more sensitive to heat than ALD, and the effect of heat from the heater 21 provided on the susceptor 2 is reduced. In addition, by providing the first gas diffusion chamber 34 below the second gas diffusion chamber 35, the path from the first gas diffusion chamber 34 to the first gas discharge hole 36 can be extended from the second gas diffusion chamber 35 to the second gas diffusion chamber 35. It can be made shorter than the path up to the gas discharge hole 37 .

<Deposition method>
Next, a film forming method using the film forming apparatus 100 configured as described above will be described.

First, the gate valve 12 is opened, and the wafer W is transferred from the vacuum transfer chamber into the chamber 1 by the transfer device and placed on the susceptor 2 . After retracting the conveying device, the gate valve 12 is closed.

When forming a TiN film on the wafer W on the susceptor 2 by the ALD process, the susceptor 2 is first raised to the processing position. The processing position when performing ALD is preferably a position close to the shower head 3 from the viewpoint of increasing the amount of gas exposure, and the distance from the shower head 3 is preferably about 1.5 to 15 mm.

Next, while continuously supplying Ar gas into the chamber 1 from the first to third Ar gas supply sources 514 to 516 of the ALD gas supply unit 501 of the gas supply unit 5, the automatic pressure control valve (APC) 42 controls the chamber pressure. Adjust the pressure in 1. At the same time, the temperature of the wafer W on the susceptor 2 heated by the heater 21 is stabilized.

Next, the valves 541 and 542 are operated to sequentially supply TiCl ₄ gas as a raw material gas and NH ₃ gas as a nitriding gas from the TiCl ₄ gas supply source 511 and the NH ₃ gas supply source 512 to perform ALD. A TiN film is formed on the wafer W by. Specifically, a step of supplying TiCl ₄ gas as a raw material gas to be adsorbed on the surface of the wafer W, a step of purging the inside of the chamber 1 with Ar gas to discharge the TiCl ₄ gas, a step of discharging the TiCl 4 gas, and a step of NH ₃ gas as a nitriding gas. A step of supplying gas to react with TiCl ₄ adsorbed on the surface and a step of purging the chamber 1 with Ar gas to discharge NH ₃ gas are repeated. As conditions at this time, the temperature of the susceptor 2 may be 350 to 480° C., and the pressure in the chamber 1 may be 133 to 1333 Pa (1 to 10 Torr).

Ar gas, which is a purge gas, may be supplied all the time during the ALD process, or may be supplied only during the purge step by operating the valves 544 and 545 . Further, when supplying an additive gas such as H ₂ gas or SiH ₄ gas, the additive gas is supplied from the additive gas supply source 513 at an appropriate timing.

When forming a TiN film by the ALD process, ALD gases such as TiCl ₄ gas, NH ₃ gas, and Ar gas are supplied from the ALD gas supply section 501 to the first gas junction section 51 . Then, the gas is supplied from the first gas confluence portion 51 to the first gas diffusion chamber 34 of the shower head 3 through the first gas flow path 54 and is discharged from the first gas discharge hole 36 into the chamber 1 toward the wafer W. .

At this time, the conductance of the ALD gas path composed of the first gas flow path 54, the first gas diffusion chamber 34, and the first gas discharge hole 36 is relatively high. Specifically, the diameter of the first gas ejection hole 36 for ejecting the ALD gas is relatively large. Therefore, TiCl ₄ gas, NH ₃ gas, and Ar gas can be discharged at a large flow rate, and it is desirable to discharge a large flow rate of gas to the wafer W in a short time. can be done.

In addition, since gas storage tanks 537, 538, and 539 are provided in the TiCl ₄ gas pipe 521, the NH ₃ gas pipe 522, and the additive gas pipe 523, these gases are temporarily stored in each gas storage tank and pressurized. It can be discharged after it has been applied. Thereby, a large flow rate of gas can be stably supplied to the wafer W, and the ALD process can be performed more advantageously.

When forming a B-SiGe film on the wafer W on the susceptor 2 by the CVD process, the susceptor 2 is first raised to the processing position. The processing position for CVD may be lower than that for ALD from the viewpoint of ensuring gas uniformity. Specifically, it is preferably located at a position about 2 to 25 mm from the shower head 3 .

Next, while continuously supplying Ar gas into the chamber 1 from the fourth to sixth Ar gas supply sources 554 to 556 of the CVD gas supply unit 502 of the gas supply unit 5, the automatic pressure control valve (APC) 42 controls the chamber pressure. Adjust the pressure in 1. At the same time, the temperature of the wafer W on the susceptor 2 heated by the heater 21 is stabilized.

Next, valves 571, 572, and 573 are opened to supply _B2H6 gas, _{SiH4 gas} , and _GeH4 gas from _B2H6 gas supply source 551, _SiH4 gas supply source ₅₅₂ , and _GeH4 gas supply source 553. A B-SiGe film is formed on the wafer W by CVD. At this time, the supply of Ar gas from the fourth to sixth Ar gas supply sources 554 to 556 may be continued or stopped. Further, as conditions at this time, the temperature of the susceptor 2 may be 350 to 480° C., and the pressure in the chamber 1 may be 666 to 2666 Pa (5 to 20 Torr).

When forming a B—SiGe film by the CVD process, the CVD gases B ₂ H ₆ gas, SiH ₄ gas, GeH ₄ gas, and Ar gas are supplied from the CVD gas supply section 502 to the second gas junction section. 52. Then, the gas is supplied from the second gas confluence portion 52 to the second gas diffusion chamber 35 of the shower head 3 through the second gas flow path 55 and discharged from the second gas discharge hole 37 into the chamber 1 toward the wafer W. .

At this time, the conductance of the CVD gas path composed of the second gas flow path 55, the second gas diffusion chamber 35, and the second gas discharge hole 37 is relatively low. Specifically, the diameter of the second gas ejection hole 37 for ejecting the CVD gas is configured to be relatively small. Therefore, the diffusion of B ₂ H ₆ gas, SiH ₄ gas, GeH ₄ gas, etc., in the processing space S is promoted, and it is desirable to uniformly supply the gas to the wafer W, and it is desirable to perform gas supply suitable for CVD. can be done.

As a process using such a film forming apparatus 100, there is a process of forming a B-SiGe film after forming a TiN film. In this case, after the wafer W is loaded into the chamber 1 and placed on the susceptor 2, a TiN film is formed by ALD as described above, and then the chamber 1 is purged and continuously A B-SiGe film is formed by CVD as described above.

As described above, according to the present embodiment, the shower head 3 having a matrix structure is used, and the ALD gas and the CVD gas are supplied through separate gas paths with conductances suitable for the respective processes. can be done. Therefore, one film forming apparatus 100 can appropriately form a TiN film by ALD and a B-SiGe film by CVD.

Conventionally, the deposition of a TiN film by ALD and the deposition of a B--SiGe film by CVD had to be performed in separate apparatuses, but in this embodiment, one deposition apparatus 100 can perform both depositions. Since it can be done, the footprint of the device can be reduced by half. In addition, it is possible to eliminate the need to transfer wafers between the ALD apparatus and the CVD apparatus, which was conventionally required, and there is no waiting time for the temperature and pressure to stabilize in the apparatus to which the wafer has been transferred. High throughput.

Furthermore, when forming a B—SiGe film after forming a TiN film, if these are performed in separate apparatuses as in the conventional case, the surface of the TiN film is oxidized during wafer transfer, and the TiN/BSiGe interface is oxidized. There is a risk that deterioration of electrical characteristics due to On the other hand, in the case of the present embodiment, the TiN film formation and the subsequent B—SiGe film formation are performed in the same film formation apparatus. It is difficult to cause deterioration of electrical properties due to oxidation of the interface.

Further, when the B-SiGe film is formed on the TiN film, if the film thickness of the B-SiGe film is thin, the surface becomes discontinuous, the morphology deteriorates, and the specific resistance increases. be. This is because the amount of flow of the B ₂ H ₆ gas, SiH ₄ gas, and GeH ₄ gas supplied during film formation causes a time lag to reach the set flow rate. In this embodiment, as described above, such a problem can be solved by providing the gas storage tanks 577, 578, and 579 in the B ₂ H ₆ gas pipe 561, the SiH ₄ gas pipe 562, and the GeH ₄ gas pipe 563. can. That is, by charging the gas storage tanks 577, 578, and 579 with B ₂ H ₆ gas, SiH ₄ gas, and GeH ₄ gas before starting film formation by CVD, when the valves are opened and film formation is started, It is possible to eliminate bias due to gas supply delay in the initial stage of the film. As a result, even when the thickness of the B--SiGe film is thin, the surface morphology of the film is improved, and variations in resistivity can be reduced.

Note that the gas storage tank is not essential in the CVD gas supply unit 502, and the gas storage tank may not be provided. At least one of the B ₂ H ₆ gas pipe 561, the SiH ₄ gas pipe 562, and the GeH ₄ gas pipe 563 may be provided with a gas storage tank. In a pipe without a gas storage tank, by starting gas supply earlier than in a pipe with a gas storage tank (first delivery), it is possible to eliminate the time lag until the set flow rate is reached.

FIG. 4 shows the relationship between the film thickness and the surface roughness Sa when a B-SiGe film is actually formed on a TiN film. Here, the relationship between the film thickness and the surface roughness Sa is shown for each gas supply with tank storage or advance delivery (with tank storage and advance delivery) and without tank storage and advance delivery (no tank storage and advance delivery). asked for a relationship. In the figure, ○ indicates tank storage and advance delivery, and ● indicates no tank storage and advance delivery. The flow rates of B ₂ H ₆ gas, SiH ₄ gas, and GeH ₄ gas were set so that the film composition was about B: 0.3 at %, Si: 5 at %, and Ge: 95 at %. In addition, in the case of "with tank storage and first delivery", the B ₂ H ₆ gas and the GeH ₄ gas were stored in the gas storage tank and then discharged, and the SiH ₄ gas was first delivered for 3 seconds.

As shown in FIG. 4, it was confirmed that in the thin film region with a film thickness of about 16 nm or less, the surface roughness was smaller in the case of "with tank storage and advance delivery". In addition, as a result of measuring the sheet resistance in the case of "with tank storage / first delivery" (film thickness: 16.2 nm) and "without tank storage / first delivery" (film thickness: 12.4 nm), "tank storage / first delivery While the value was 1281 Ω/sq in the case of "no resistance", it was a small value of 787 Ω/sq in the case of "with tank storage and advance delivery".

<Processing system>
Next, a processing system equipped with a film forming apparatus according to one embodiment will be described.
FIG. 5 is a horizontal sectional view schematically showing an example of a processing system equipped with a film forming apparatus according to one embodiment.

The processing system 200 includes, as main components, four processing apparatuses 100 capable of performing both ALD and CVD as described above, three load lock chambers 104, a vacuum transfer chamber 101, an atmospheric transfer chamber 105, and an overall and a control unit 111 .

The load lock chamber 104 is provided between the vacuum transfer chamber 101 and the atmospheric transfer chamber 105, and when transferring the wafer W between the vacuum transfer chamber 101 and the atmospheric transfer chamber 105, the load lock chamber 104 is controlled between the atmospheric pressure and the vacuum. It adjusts the pressure.

The vacuum transfer chamber 101 is evacuated by a vacuum pump and maintained at a degree of vacuum that matches the pressure inside the processing chambers of the four film forming apparatuses 100, and has a transfer mechanism 108 inside. Four film forming apparatuses 100 are connected to the vacuum transfer chamber 101 through gate valves G, and three load lock chambers 104 are connected through gate valves G1.

A transport mechanism 108 transports wafers W to four film deposition apparatuses 100 and three load lock chambers 104 . The transport mechanism 108 has two independently movable transport arms 109a and 109b.

The atmospheric transfer chamber 105 is maintained in an atmospheric atmosphere, and three load lock chambers 104 are connected to one wall via gate valves G2. A wall portion of the atmospheric transfer chamber 105 opposite to the mounting wall portion of the load lock chamber 104 has three carrier mounting ports 106 for mounting carriers (such as FOUPs) C containing wafers W thereon. An alignment chamber 107 for alignment of the wafer W is provided on the side wall of the atmospheric transfer chamber 105 . A down flow of clean air is formed in the atmospheric transfer chamber 105 .

A transfer mechanism 110 is provided in the atmosphere transfer chamber 105 . The transport mechanism 110 transports the wafer W to the carrier C, load lock chamber 104 and alignment chamber 107 .

The overall control unit 111 controls the entire processing system 200 and sends control commands to the four film forming apparatuses 100 . It also controls the exhaust mechanism and gas supply mechanism of the vacuum transfer chamber 101 and the load lock chamber 104, the transfer mechanisms 108 and 110, the drive system of the gate valves G, G1 and G2, and the like. The overall control unit 111 includes a main control unit having a CPU (computer) that actually performs these controls, an input device (keyboard, mouse, etc.), an output device (printer, etc.), a display device (display, etc.), a storage device ( storage medium). The main controller causes the processing system 200 to perform desired processing operations based on the processing recipes stored in the storage medium of the storage device.

Next, an outline of the operation of the processing system 200 configured in this way will be described.

First, the wafer W is taken out from the carrier C connected to the atmosphere transfer chamber 105 by the transfer mechanism 110, the gate valve G2 of one of the load lock chambers 104 is opened, and the wafer W is transferred into the load lock chamber 104. FIG. After the gate valve G2 is closed, the inside of the load lock chamber 104 is evacuated. When the vacuum degree of the vacuum transfer chamber 101 is reached, the gate valve G1 is opened and the wafer W is taken out from the load lock chamber 104 by the transfer mechanism .

Then, the wafer W taken out is transferred to one of the film forming apparatuses 100, and the TiN film is formed by ALD and the B-SiGe film is formed by CVD as described above. The gate valve G is opened and closed when the wafer W is loaded into and unloaded from each device.

For the wafer W for which the film formation process by the film forming apparatus 100 has been completed, the gate valve G1 of one of the load lock chambers 104 is opened, and the wafer W is carried into the load lock chamber 104 by the transfer mechanism 108 . Then, the inside of the load lock chamber 104 is returned to the atmosphere, the gate valve G2 is opened, and the wafer W in the load lock chamber 104 is returned to the carrier C by the transfer mechanism 110 . A plurality of wafers W are processed as described above in parallel, and the number of wafers W housed in the carrier C is processed.

Conventionally, when using such an efficient processing system, it is necessary to use a processing system equipped with four film forming apparatuses for ALD and a processing system equipped with four film forming apparatuses for performing CVD. The footprint (installation area) becomes large. Moreover, it is necessary to expose the wafer after forming the TiN film to the atmosphere, and the problem of interfacial oxidation cannot be solved. Also, two conventional film forming apparatuses for ALD and two conventional film forming apparatuses for CVD can be installed in one processing system, but in this case, the throughput is half that of the processing system 200 described above. Moreover, in such a processing system, although the wafer after the TiN film is formed can be transferred in a vacuum atmosphere, it is difficult to completely eliminate oxygen, and interfacial oxidation of the wafer occurs to some extent during transfer. occur.

On the other hand, in the processing system 200, a plurality of wafers W can be processed concurrently by the four film deposition apparatuses 100 capable of both ALD and CVD. The throughput can be further increased while reliably preventing the

<Other applications>
Although the embodiments have been described above, the embodiments disclosed this time should be considered as examples and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

For example, in the above embodiments, the case of forming a TiN film by ALD and forming a B—SiGe film by CVD has been described, but the present invention is not limited to these films, and film formation by ALD and film formation by CVD is possible. Any film forming apparatus that forms a film can be applied.

Further, in the above embodiments, the semiconductor wafer is used as an example of the substrate, but the substrate is not limited to the semiconductor wafer, and other substrates such as glass substrates used for FPDs (flat panel displays) and ceramic substrates may be used.

1; chamber 2; susceptor 3; shower head 4; exhaust unit 5; gas supply unit 6; control unit 34; 1st gas channel 55; 2nd gas channel 100; film forming apparatus 200; processing system 501;

Claims (12)

a processing container in which the substrate is accommodated;
a mounting table for mounting the substrate in the processing container;
an ALD gas supply unit for supplying an ALD gas used for film formation by ALD;
a CVD gas supply unit for supplying a CVD gas used for film formation by CVD;
a shower head to which the ALD gas and the CVD gas are supplied and which discharges the ALD gas and the CVD gas into the processing container;
a heating unit that heats the substrate on the mounting table;
an exhaust unit for exhausting the inside of the processing container;
and capable of performing film formation by ALD and film formation by CVD on the substrate on the mounting table,
The shower head is
a first gas diffusion chamber to which the ALD gas is supplied;
a second gas diffusion chamber to which the CVD gas is supplied;
a first gas ejection hole for ejecting the ALD gas from the first gas diffusion chamber;
a second gas ejection hole for ejecting the CVD gas from the second gas diffusion chamber;
has
The film forming apparatus, wherein the conductance of the first gas ejection holes is greater than the conductance of the second gas ejection holes. 2. The film forming apparatus according to claim 1, wherein the diameter of said first gas ejection hole is larger than the diameter of said second gas ejection hole. 3. The film forming apparatus according to claim 1, wherein the number of said first gas ejection holes is greater than the number of said second gas ejection holes. 4. The film forming apparatus according to claim 1, wherein said first gas ejection hole and said second gas ejection hole are concentrically arranged. 5. The film forming apparatus according to claim 1, wherein said first gas diffusion chamber is provided at a position closer to said mounting table than said second gas diffusion chamber. The ALD gas supply unit has a raw material gas pipe for supplying a raw material gas and a reaction gas pipe for supplying a reaction gas that reacts with the raw material gas. 6. The film forming apparatus according to any one of claims 1 to 5, further comprising a valve for cutting off the supply of the gas, and a gas storage tank provided on the upstream side of the valve for storing gas. A Ti-containing gas and an N-containing gas are supplied from the ALD gas supply unit to form a TiN film on the substrate by ALD,
A B-containing gas, a Si-containing gas, and a Ge-containing gas are supplied from the CVD gas supply unit, and a B-doped SiGe film is formed on the substrate by CVD. The film forming apparatus according to any one of the items. In the CVD gas supply unit, at least one of a B-containing gas pipe supplying the B-containing gas, a Si-containing gas pipe supplying the Si-containing gas, and a Ge-containing gas pipe supplying the Ge-containing gas is supplied with 8. The film forming apparatus according to claim 7, further comprising a gas storage tank for storing the gas, and supplying the gas after storing the gas in the gas storage tank. A film forming method for forming a film on a substrate by the film forming apparatus according to any one of claims 1 to 6,
A step of supplying the ALD gas from the ALD gas supply unit, discharging the ALD gas from the shower head into the processing container, and forming a first film on the substrate by ALD;
a step of supplying the CVD gas from the CVD gas supply unit, discharging the CVD gas from the shower head into the processing container, and forming a second film on the substrate by CVD;
A film forming method. 10. First, the step of forming the first film by ALD is performed, and then the step of forming the second film by CVD is continuously performed on the first film of the substrate. The film forming method described in . The step of forming the first film includes forming a TiN film as the first film on the substrate by ALD by supplying a Ti-containing gas and an N-containing gas from the ALD gas supply unit,
The step of depositing the second film comprises supplying a B-containing gas, a Si-containing gas, and a Ge-containing gas from the CVD gas supply unit, and forming a TiN film as the first film on the substrate by CVD. 11. The film forming method according to claim 9, wherein a B-doped SiGe film is formed as said second film in succession to said second film. 12. The step of forming the second film includes storing at least one of the B-containing gas, the Si-containing gas, and the Ge-containing gas in a gas storage tank and then discharging the gas, or discharging the gas in advance. The film forming method described in .

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