JPH11302842A - Sputtering method and sputtering apparatus - Google Patents

Abstract

(57) [Problem] To form a film having a sufficiently high side coverage ratio as well as a bottom coverage ratio for a hole having an aspect ratio of 7 or more. SOLUTION: Film formation on the surface of a substrate 9 in which fine holes are formed is divided into a bottom film formation process and a side film formation process. In the bottom surface deposition process, the distance between the substrate 9 and the target 42 is set to a short first distance by the distance changing mechanism 46.
The inside of the sputtering chamber 2 is set to a high first pressure by the gas introduction system 44 and the exhaust system 41, and the sputter particles emitted from the target 42 are ionized and vertically incident on the substrate 9. Film formation is performed at an increased film formation rate. In the side film forming step, the distance between the substrate 9 and the target 42 is set to a long second distance by the distance changing mechanism 46 and the gas introduction system 44 is set.
Then, the inside of the sputtering chamber 2 is set to a low second pressure by the exhaust system 41, and the film is formed by increasing the film forming rate on the side surface of the hole by a low-pressure remote sputtering method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus for forming a predetermined thin film on the surface of a substrate by sputtering, and more particularly, to a sputtering apparatus suitable for forming a film on the inner surface of minute holes formed on the surface of the substrate. It concerns the device.

[0002]

2. Description of the Related Art In the process of manufacturing semiconductor devices such as various memories and logics, a sputtering method is often used for forming a conductive film for wiring and a barrier film for preventing mutual diffusion of different layers. Although various characteristics are required for the sputtering process, it has recently been strongly required that the inner surface of the hole formed on the surface of the substrate can be covered with a thin film having a sufficient thickness. More specifically, in the manufacture of many semiconductor devices having an FET structure, a contact hole is provided in an insulating layer formed above a channel, and the inside of the contact hole is filled with a conductive film to form a channel wiring. ing. In the process of forming such a channel wiring, a barrier film is formed on the inner surface (bottom surface and side surface) of the contact hole in order to prevent mutual diffusion between the conductive film for wiring and the underlying channel. In the manufacture of a device having a multilayer wiring structure, a similar barrier film may be provided on the inner surface of a through hole for an interlayer wiring to prevent interdiffusion between an interlayer wiring and a base wiring layer. Such contact holes and through-holes have been developed due to the high integration and high functionality of devices.
The aspect ratio tends to be higher and higher. The aspect ratio is the ratio of the depth of the hole to the diameter or width of the opening of the hole. Sputtering is a technique in which particles of a target material (hereinafter, sputtered particles) are released from the target by sputtering the target, and the sputtered particles reach the surface of the target to form a film.
As the aspect ratio increases, it becomes more difficult for sputtered particles to reach the entire inner surface of the hole. As a result,
Film formation on the inner surface of the hole becomes insufficient.

As an index of film formation on an inner surface of a minute hole such as a contact hole or a through hole, there is an index called a bottom coverage ratio. The bottom coverage ratio is a ratio of a film formation rate on the bottom surface of the hole to a film formation rate on a surface around the hole (a surface outside the hole). as mentioned above,
With respect to holes having a high aspect ratio, there is a problem that the bottom coverage ratio is reduced because the sputter particles do not sufficiently reach the bottom surfaces of the holes. When the bottom coverage ratio decreases, in the case of a barrier film, the barrier film becomes thinner at the bottom of the hole, which may cause a fatal defect in device characteristics such as junction leak. As a sputtering technique for improving the bottom coverage ratio, an ionization sputtering technique has been put to practical use. Ionized sputtering ionizes sputtered particles emitted from a target, sets an electric field in the depth direction of a hole, and guides ionized sputtered particles (hereinafter, ionized sputtered particles) perpendicularly to a substrate by an electric field into a hole. It is a technique to reach. In ionized sputtering, since ionized sputtered particles fly perpendicular to the substrate and enter a large amount of the substrate, there is an advantage that a film having a high bottom coverage ratio can be formed.

[0004]

However, the aspect ratio of holes has been increasing steadily against the background of the increasing degree of integration of devices. For this reason, it is expected that there is a limit even in the ionization sputtering method. That is, taking a DRAM (a random read / write memory requiring a memory holding operation) as an example, mass production of a 64-Mbit class DRAM is about to start at present. In the 64-Mbit class, the line width of the circuit is around 0.25 microns, and the aspect ratio of the contact hole is about 4 to 5. With such holes, a bottom coverage ratio of about 15% can be obtained by the above-described ionization sputtering, and it is considered that mass production is possible. However, in a device having a line width of 0.18 to 0.13 microns, which is called a next-generation device, the aspect ratio is expected to reach about 7 to 10. With respect to holes having an aspect ratio increased to this level, it is impossible to form a film with a sufficient bottom coverage rate by the ionization sputtering, and it is considered that a technical breakthrough is required.

[0005] This point will be described more specifically with reference to FIG. FIG. 6 is a diagram for explaining the technical difficulty of film formation for a hole having a high aspect ratio. FIG. 6 is a schematic cross-sectional view of a substrate 9 having holes having an aspect ratio of 10 as an example of a substrate used for manufacturing a next-generation device. When the above-described conventional ionization sputtering technique is used for film formation in the hole 90 shown in FIG. 6, the bottom coverage ratio is insufficient under the same conditions as the conventional one,
Practical application is difficult. Considering the extension of conventional ionized sputtering, some improvement is made by improving the ionization efficiency of the sputtered particles or by increasing the intensity of the electric field for guiding the ionized sputtered particles, and in terms of the bottom coverage ratio, It may be possible to respond to mass production.

However, according to studies by the inventors, it has been found that such improvement leads to a problem of a decrease in the side coverage rate, which is a new obstacle to mass production. The side coverage ratio is a ratio of a film forming rate on the side surface 91 of the hole 90 to a surface outside the hole 90. More specifically, when film formation is performed by improving ionization efficiency to ionize more sputtered particles, increasing the electric field intensity and flying more ionized sputtered particles in the depth direction of the hole, Most of the sputtered particles incident on the substrate 9 fly in the depth direction of the hole 90. As a result, even if the particles enter the hole 90, most of the sputtered particles will
, And hardly reaches the side surface 91 of the hole 90. For this reason, the film forming speed on the side surface 91 of the hole 90 is extremely reduced. In the case of a barrier film, it is considered that not only the bottom coverage rate but also the side coverage rate is required to be about 20%, but it is difficult to achieve this on an extension of the above-mentioned conventional ionized sputtering. It is thought that an appropriate solution is necessary.

The invention of the present application has been made to solve the above-mentioned problem, and is aimed at a next-generation device having a line width of 0.18 μm or less. The present invention proposes a breakthrough in which a film having a sufficiently high side coverage ratio as well as a bottom coverage ratio can be formed.

[0008]

According to a first aspect of the present invention, there is provided a sputtering method for forming a predetermined thin film on the inner surface of a hole formed in a surface of a substrate by sputtering. The ionization of the sputter particles emitted from the target is performed, and an electric field having a component in the depth direction of the hole is set. Bottom film forming step and a side film forming step of increasing the distance between the target and the substrate and lowering the pressure as compared to the bottom film forming step to increase the film forming rate on the side surface of the hole by performing sputtering. In this case, the bottom film forming step and the side film forming step are performed continuously in a vacuum. According to another aspect of the present invention, there is provided a sputtering apparatus for forming a predetermined thin film by sputtering on an inner surface of a hole formed on a surface of a substrate, wherein the sputtering apparatus includes an exhaust system. A gas introduction system for introducing a predetermined gas into the sputtering chamber, a target provided so that a surface to be sputtered is exposed in the sputtering chamber, a sputtering power supply for applying a voltage to the target and sputtering the target, Ionization means for ionizing sputter particles emitted from a target by sputtering, a substrate holder for holding a substrate at a predetermined position in a sputtering chamber, and acceleration of sputter particles ionized by the ionization means perpendicular to the substrate Field setting means for setting an electric field for the target, the target and the substrate And a control unit capable of controlling an exhaust system, a gas introduction system, an ionization unit, an electric field setting unit, and a distance change mechanism, and the control unit controls the ionization. When operating the means and the electric field setting means, the exhaust system and the gas introduction system are controlled so as to keep the pressure in the sputtering chamber at a high first pressure, and the distance between the target and the substrate is short. Control the distance changing means so that the distance is equal to, and when the ionization means and the electric field setting means are not operated, the evacuation system so as to keep the pressure in the sputtering chamber at a second pressure lower than the first pressure. And the distance changing means is controlled so that the distance between the target and the substrate becomes a second distance longer than the first distance. According to a third aspect of the present invention, in the configuration of the second aspect, the sputter power supply is a high-frequency power supply, and the sputter particles are ionized by an electric field set by the high-frequency power supply. It is possible that the sputtering power supply is also used as the ionization means, further provided with a negative DC power supply for applying a negative DC voltage to the target,
A switch circuit for selectively or simultaneously applying the voltage of the high-frequency power supply and the voltage of the negative DC power supply to the target; Also, in order to solve the above problems,
The invention according to claim 4 is a multi-chamber type sputtering apparatus in which at least one load lock chamber and a plurality of processing chambers are hermetically connected around a separation chamber provided in the center,
One of the plurality of processing chambers is a first sputtering chamber, the other is a second sputtering chamber, and the first sputtering chamber has a first evacuation chamber for evacuating the inside of the first sputtering chamber. System, a first gas introduction system for introducing a predetermined gas into the first sputtering chamber, a first target provided such that a surface to be sputtered is exposed in the first sputtering chamber, and a voltage applied to the first target. A first sputtering power supply for applying a pressure to the target, ionizing means for ionizing sputter particles emitted from the first target by sputtering, and a second power supply for holding the substrate at a predetermined position in the first sputtering chamber. One substrate holder and an electric field for accelerating the sputtered particles ionized by the ionization means perpendicularly to the substrate are set. Field setting means is provided, the first exhaust system and the first gas introduction system can maintain a high first pressure in the first sputtering chamber, and the first substrate holder And holding the substrate so that the distance between the first target and the first target is a short first distance, the second sputtering chamber, a second exhaust system for exhausting the second sputtering chamber, a second exhaust system, A second target provided such that the surface to be sputtered is exposed in the sputtering chamber, and a second sputtering power supply for applying a voltage to the second target to sputter the second target,
A second substrate holder for holding the substrate at a predetermined position in the second sputtering chamber is provided, and the second exhaust system maintains the inside of the second sputtering chamber at a second pressure lower than the first pressure. And the second substrate holder holds the substrate such that a distance between the substrate and the second target is a second distance longer than the first distance. In order to solve the above-mentioned problem, the invention according to claim 5 is the invention according to claim 2, 3 or 4, wherein the first pressure is in a range of 10 mTorr to 100 mTorr, and the second pressure is 1 mTorr or less, the first distance is a distance within a range of 1 / 2.5 to 1/1 of the maximum width of the substrate, and the second distance is 1 to 1.5 times the maximum width of the substrate. The distance is within the range.

[0009]

Embodiments of the present invention will be described below. First, a first embodiment belonging to the invention of the sputtering apparatus of claims 2 and 3 will be described.
FIG. 1 is a schematic plan view showing a configuration of a sputtering apparatus according to a first embodiment which belongs to the second and third aspects of the present invention. The sputtering apparatus shown in FIG. 1 is a multi-chamber type apparatus, which includes a separation chamber 1 disposed at the center and a plurality of processing chambers 2, 3, 4, which are hermetically connected around the separation chamber 1.
8 and two load lock chambers 5. Each chamber 1, 2, 3, 4,
5, 8 are provided with a dedicated or combined exhaust system (not shown),
The gas is exhausted to a predetermined pressure. A gate valve 6 is provided at a connection point between the chambers.

In the separation chamber 1, a transfer robot 11 is provided as a transfer mechanism for transferring the substrate 9 between the chambers. Transfer robot 11
Uses an articulated robot. The transfer robot 11 takes out the substrates 9 one by one from one of the load lock chambers 5 and treats each of the processing chambers 2, 3, 3.
4 and 8, the processing is sequentially performed, and after the last processing is completed, the processing is returned to one of the load lock chambers 5. An autoloader 7 is provided outside the load lock chamber 5. The autoloader 7 takes out the substrates 9 one by one from the external cassette 62 on the atmosphere side, and stores the substrates 9 in the lock cassette 51 in the load lock chamber 5. One of the processing chambers 2, 3, 4, and 8 is a sputter chamber 4 for forming a predetermined thin film by sputtering.
It is. One of the processing chambers 2, 3, and 8 is a preheat chamber 2 for preheating the substrate 9 before sputtering, and another is a natural oxidation of the surface of the substrate 9 before sputtering. A pre-processing etching chamber 3 for performing pre-processing etching for removing a film or a protective film.

Next, the configuration of the sputtering chamber 4 which is a main part of the apparatus of the present embodiment will be described with reference to FIG. FIG. 2 is a schematic front view showing the configuration of the sputtering chamber 4 shown in FIG. As shown in FIG. 2, the sputtering chamber 4 includes an exhaust system 41 for exhausting the inside, a target 42 provided in the sputtering chamber 4 so that a surface to be sputtered is exposed, and a predetermined power supplied to the target 42. Two sputtering power supplies 421 and 422 to be provided;
A magnet mechanism 43 provided behind the target 42, a gas introduction system 44 for introducing a predetermined sputtering gas into the sputtering chamber 4, and the substrate 9 at a predetermined position in the sputtering chamber 4 facing the target 42. And a substrate holder 45 for performing the operation.

The exhaust system 41 uses a vacuum pump 411 such as a cryopump to evacuate the inside of the sputtering chamber 4 to 10 ^-8.
It is configured to be able to exhaust to about Torr. Exhaust system 41
Has an exhaust speed adjuster 412 such as a variable orifice. The target 42 is attached to the sputtering chamber 4 via an insulating material 420. Target 4
2 is made of titanium in this embodiment. The two sputter power supplies 421 and 422 form a major feature of the apparatus of the present embodiment. One of the two sputtering power supplies is a power supply (hereinafter, sputtering DC power supply) 421 for applying a negative DC voltage to the target 42, and the other is a power supply for applying a high frequency voltage (hereinafter, sputtering high frequency power supply). 422. As the DC power supply 421 for sputtering, -400 to
What applies a voltage of about −600 V to the target 42 is used. The power supplied to the target 42 by the DC power supply 421 for sputtering is about 10 to 20 kW. Also,
As the sputtering high-frequency power supply 422, the frequency is 13.
A device which applies a voltage of 56 MHz to an effective value of about 300 to 500 V to the target 42 is used. The power supplied to the target 42 from the sputtering high-frequency power supply 422 is 3 to 8
It is about kW. Note that a matching unit 424 is provided between the sputtering high-frequency power supply 422 and the switch circuit 423. When the DC power supply 421 for sputtering is used, the target 42 is sputtered in the same manner as ordinary DC sputtering. In addition, when the high frequency power supply for sputtering 422 is used,
Sputtering is performed according to the principle of high frequency sputtering.

The high-frequency sputtering will be described in more detail. A capacitance such as a capacitor is provided between the target 42 and the high-frequency power supply 422 for sputtering. When a high-frequency voltage is applied to the target 42 by the high-frequency power supply 422 for sputtering, a high-frequency discharge is generated in a space facing the target 42 to form plasma. At this time, when a high-frequency voltage is applied to the target 42 via the capacitance, electrons and positive ions in the plasma act on charge and discharge of the capacitance, and a negative self-bias potential is applied to the substrate 9 due to a difference in mobility between the electrons and the positive ions. Occurs.
The space potential of the plasma is a positive potential of about 0 to 40 volts, and an electric field whose potential gradually decreases toward the target 42 is set between the plasma and the target 42 where the negative self-bias potential is generated. Positive ions in the plasma are accelerated by the electric field, collide with the target 42, sputter the target 42, and the sputter discharge continues.
The DC power supply 421 for sputtering and the high-frequency power supply 422 for sputtering are connected in parallel to the target 42, and a switch circuit 423 is provided at a branch portion thereof. As can be seen from FIG. 2, the switch circuit 423
Are the DC power supply 421 for sputtering and the high frequency 42 for sputtering.
2 or both of them can be connected at the same time.

The magnet mechanism 43 includes a columnar central magnet 431 disposed at the center, a ring-shaped peripheral magnet 432 surrounding the central magnet 431, a central magnet 431 and a peripheral magnet 432.
And a yoke 433 connecting the two. The front surface of the center magnet 431 and the front surface of the peripheral magnet 432 have different magnetic poles, and an arch-shaped magnetic force line 434 as shown in FIG. The electric field set in the sputtering chamber 4 by the sputtering DC power supply 421 via the target 42 is orthogonal to the magnetic field near the apex of the arch-shaped line of magnetic force 434. For this reason, in the formed sputter discharge, the electrons perform magnetron motion, and the magnetron discharge is achieved. Therefore, the efficiency of ionization of neutral gas molecules is increased, and sputtering can be performed with high efficiency.

In this embodiment, the gas introduction system 44 introduces an argon gas as a sputtering gas. The gas introduction system 44 includes a pipe 441 connecting the cylinder 442 storing the argon gas and the sputtering chamber 4,
Valve 443 and flow regulator 444 provided on pipe 441
And so on. The substrate holder 45 is configured to place and hold the substrate 9 on the upper surface. The substrate holder 45 is provided with an electrostatic attraction mechanism for fixing the substrate 9 at a predetermined position by electrostatic attraction as needed. Also,
A heater 451 for heating the substrate 9 to a predetermined temperature is provided in the substrate holder 45.

A major feature of the apparatus of the present embodiment is that the substrate holder 45 is provided with a distance changing mechanism 46 for changing the distance between the target 42 and the substrate 9. Specifically, the substrate holder 45 is supported by a support 452. Distance changing mechanism 46
Is a holding plate 463 holding the lower end of the support 452,
The driven body 464 to which the holding plate 463 is fixed, and the driven body 4
Ball screw 461 for driving the screw 64, and the ball screw 4
It mainly comprises a motor 462 for rotating 61.

The driven body 464 is a cylindrical member having an inner diameter adapted to the outer diameter of the ball screw 461. The inner surface of the driven body 464 is precisely threaded and meshes with the ball screw 461. In addition, the driven body 464
Are not rotated by a rotation stopper (not shown). When the ball screw 461 is rotated by the motor 462, the force of this rotation is transmitted to the driven body 464. Since the driven body 464 is not rotated by a rotation stopper (not shown), it only moves up and down. As a result, the column 45 is held via the holding plate 463 fixed to the driven body 464.
2 moves up and down, and accordingly, the substrate holder 45 also moves up and down. Since the target 42 is fixed in the sputtering chamber 4, the distance between the substrate 9 placed on the substrate holder 45 and the target 42 can be changed by the operation of the distance changing mechanism 46 as described above. I have. The column 452 passes through the bottom plate of the sputtering chamber 4 in an airtight manner. Further, a sealing means 453 such as a mechanical seal for sealing the penetrating portion while allowing the column 452 to move up and down is provided.

Another feature of the apparatus of this embodiment is that ionization sputtering can be performed in the sputtering chamber 4. That is, the apparatus of the present embodiment has ionization means for ionizing sputter particles emitted from the target 42. The high frequency power source 422 for sputtering is also used for this ionization means.
The ionization means includes a high-frequency power source 422 for sputtering, an auxiliary electrode 47 for effectively performing ionization sputtering, an electric field setting means 48, and the like.

The auxiliary electrode 47 has a cylindrical shape provided so as to surround a flight space of sputter particles between the target 42 and the substrate holder 45. The auxiliary electrode 47 is grounded via a capacitor 471 provided outside the sputtering chamber 4. An auxiliary power supply 472 is provided in parallel with the capacitor 471. And the auxiliary power supply 4
A switch 473 is provided at a portion where the line to 72 and the line to the capacitor 471 are branched, and it is possible to select whether to ground the auxiliary electrode 47 via the capacitor 471 or to ground via the auxiliary power supply 472. I can do it. The auxiliary power supply 472 is a high-frequency power supply, for example, having a frequency of 13.56 MHz and an output of about 2 kW. The sputter chamber 4 is grounded, and an insulating material (not shown) is provided at a portion where the line connecting the auxiliary electrode 47 and the switch 473 passes through the wall of the sputter chamber 4 in an airtight manner.

When the sputtering high-frequency power supply 422 is operated while the sputtering gas is being introduced into the sputtering chamber 4 by the gas introduction system 44, as described above,
The target 42 is subjected to high frequency sputtering. At this time, the gas is turned into plasma by the high-frequency electric field to form plasma. When passing through the plasma, the neutral sputtered particles emitted from the target 42 collide with ions or electrons in the plasma and are ionized (hereinafter, ionized sputtered particles). The ionized sputtered particles are accelerated by the electric field set by the electric field setting means 48, are extracted from the plasma, fly at an angle more perpendicular to the substrate 9, and enter the substrate 9. Specifically, the electric field setting means 48 employs a high frequency power supply 481 which applies a high frequency voltage to the substrate holder 45 and applies a negative self-bias voltage to the substrate 9 by the interaction between the high frequency and the plasma. As the high-frequency power supply 481, for example, a power supply with a 13.56 MHz output of about 1 KW can be used. A matching device 482 is provided between the high frequency power supply 481 and the substrate holder 45. Further, when the substrate 9 and the substrate holder 45 are both conductors, a predetermined capacitor is provided in a high-frequency transmission path, and a high-frequency voltage is applied to the substrate 9 via the capacitor.

When a high-frequency voltage is applied to the substrate 9 via a capacitance as in the case of the high-frequency power source 422 for sputtering described above, a self-bias voltage is generated in the substrate 9 and the substrate 9 is moved between the substrate 9 and the plasma toward the substrate 9. Thus, an electric field whose potential gradually decreases is set. The direction of the electric field is perpendicular to the substrate 9, and the positively ionized sputtered particles are accelerated by the electric field and vertically incident on the substrate 9. In the ionization sputtering, ions in the plasma change the direction of movement so as to follow a periodic change in the direction of the electric field. At this time, since the auxiliary electrode 47 is insulated from the ground potential by the capacitor 471 or is connected to the auxiliary power supply 472, an electric field is set near the auxiliary electrode 47. As a result, the ions move over a wide range, and there is a high probability that the ions collide with the neutral sputtered particles and are ionized. That is,
The auxiliary electrode 47 has the function of increasing the ionization efficiency of sputtered particles.

The apparatus of the present embodiment has a control unit (not shown) for controlling the operation in the sputtering chamber 4. The control unit includes an exhaust system 41, a sputtering power supply 421,
422, a switch circuit 423, a gas introduction system 44, a heater 451, a distance changing mechanism 46, and a control signal are transmitted to the ionization means 47 and the like, so that each unit performs an operation described later.

Next, the operation of the apparatus in the sputtering chamber 4 will be described with reference to FIG. First, the substrate 9 is carried into the sputtering chamber 4 from the separation chamber 1 through the gate valve 6 by the transfer robot 11. The inside of the sputtering chamber 4
Exhausted to a predetermined pressure by an exhaust system 41 in advance,
The substrate 9 is placed on the substrate holder 45. The heater 451 in the substrate holder 45 is operated in advance, and the substrate 9 placed on the substrate holder 45 is rapidly heated to a predetermined temperature by the heat of the heater 451, and the temperature is maintained. After closing the gate valve 6, the gas introduction system 4
4 is operated to perform sputtering. A major feature of the apparatus and method of the present embodiment is that, when forming a film on the substrate 9 having fine holes formed on the surface, a bottom film forming step in which the film forming rate on the bottom surface of the hole is increased, The point is that the process is performed separately from the side surface film forming step in which the film forming speed on the side surface of the hole is increased. Although there is no particular limitation on the order, the following example will be described assuming that the bottom surface film forming step is performed first, and then the side surface film forming step is performed.

First, when performing the bottom film forming step, the inside of the sputtering chamber 4 is kept at a high first pressure by controlling the not-shown evacuation speed controller and flow rate controller 444. Further, the distance changing mechanism 46 moves the substrate holder 45 in advance so that the distance between the target 42 and the substrate 9 (hereinafter, referred to as TS distance) becomes a short first distance. In this state, the sputtering high-frequency power supply 422 and the electric field setting means 48 are operated to perform ionized sputtering. That is, as described above, the high-frequency sputtering power supply 422 performs high-frequency sputtering with the voltage applied to the target 42 and ionizes the sputtered particles in the plasma. Then, the ionized sputtered particles are drawn out by the electric field set by the electric field setting means 48 and vertically incident on the substrate 9. The sputtered particles are on the substrate 9
When the light is incident vertically, the sputtered particles can easily reach the bottom surface of the hole, so that film deposition on the bottom surface of the hole is promoted. That is, the film forming speed on the bottom surface of the hole increases.

Next, a side face film forming step is performed. In particular,
The distance changing mechanism 46 is operated to move the substrate holder 45 in advance so that the TS distance becomes the second long distance. In addition, an unillustrated evacuation rate controller and flow rate controller 444 are controlled to maintain the inside of the sputtering chamber 4 at a low second pressure. In this state, the DC power supply 421 for sputtering is operated to perform DC sputtering. At this time, since the TS distance is long and the pressure is low, film deposition on the side surface of the hole is promoted, and sputtering with a high side surface deposition rate can be performed. Then, after performing this sputtering for a predetermined time, the operations of the high-frequency power source for sputtering 422, the electric field setting means 48, the gas introduction system 44 and the like are stopped, and the substrate 9 is taken out from the sputtering chamber 4.

The improvement of the side surface film forming speed in the above-described operation in the sputtering chamber 4 will be described in more detail with reference to FIG. FIG. 3 is a diagram schematically illustrating an improvement in the side surface film forming speed. As shown in FIG.
If the TS distance is increased from L1 to L2, the hole 90
The area of the surface to be sputtered of the target 42 that can be seen from one point P of the side surface is larger in the case of L2 than in L1 (S1 <S2). The area (S1, S2) of the surface to be sputtered of the target 42 is the area of the emission part of the sputtered particles that can reach one point P on the side surface of the hole. The amount of sputter particles reaching P increases. For this reason, the side surface deposition rate can be increased. When the pressure is reduced, the sputtered particles flying toward the side surface of the hole 90 are less scattered by gas molecules. Therefore, the sputtered particles more reliably reach the side surface of the hole 90, which contributes to the improvement of the side surface film forming speed.

In the operation in the sputtering chamber 4, the high first pressure is 10 mTorr to 100 mT
It is preferable to be in the range of orr. If it is higher than this range, there is a problem that ionized sputtered particles are scattered by the presence of a large number of gas molecules and cannot reach the substrate 9 sufficiently. On the other hand, if it is lower than this range, there is a problem that the plasma density is lowered and the ionization efficiency becomes insufficient. Also, the low second pressure is 1 mT within a range where the discharge is maintained.
It is preferably set to orr or lower. If the pressure is higher than this, there is a problem that the effect of the low-pressure remote sputtering described above cannot be sufficiently obtained. Further, it is preferable that the short first distance is specifically a distance in a range of 1 / 2.5 to 1/1 of the maximum width of the substrate 9. The “maximum width” of the substrate 9
The term “width” means the width of the substrate 9 as viewed in the direction in which the width becomes the widest, and the diameter if the substrate 9 is circular. If the first distance is shorter than the above range, the in-plane distribution of film characteristics such as film thickness may be deteriorated. Also, if it is longer than this range,
The number of sputter particles that cannot reach the substrate 9 is unnecessarily increased, and the efficiency is deteriorated. Further, it is preferable that the long second distance is a distance within a range of 1 to 1.5 times the maximum width of the substrate. If the length is longer than this range, the efficiency of film formation becomes too poor, which is not preferable. On the other hand, if it is shorter than this range, the effect of the low-pressure remote sputtering cannot be obtained.

Next, returning to FIG. 1, another configuration of the sputtering apparatus of the present embodiment will be described. The pre-treatment etching chamber 3 shown in FIG.
Is etched to remove a natural oxide film and a protective film on the surface of the substrate 9. The pre-treatment etching chamber 3 forms plasma inside, and causes ions in the plasma to collide with the surface of the substrate 9 to etch away the natural oxide film and the protective film. In addition, the preheat chamber 2 is configured to heat the substrate 9 prior to film formation and release the occluded gas of the substrate 9. If the occluded gas is not released, there is a problem that the occluded gas is rapidly released due to heat during film formation and the surface of the film becomes rough due to foaming. A heat stage (not shown) that is heated and maintained at a predetermined temperature is provided in the preheat chamber 2. The substrate 9 is placed on this heat stage and is preheated by being heated to a predetermined temperature.

Next, the overall operation of the sputtering apparatus of this embodiment will be described. The substrate 9 accommodated in the external cassette 62 is carried into the in-lock cassette 51 in the load lock chamber 5 by the autoloader 7.
The substrate 9 carried into the lock cassette 51 is first carried into the preheat chamber 2 by the transfer robot 11 provided in the separation chamber 1. The substrate 9 carried into the preheat chamber 2 is placed on a heat stage (not shown) and heated to a predetermined temperature. Thereby, the substrate 9 is preheated, and the occluded gas in the substrate 9 is released. Next, the substrate 9 is transferred to the pre-treatment etching chamber 3, and the natural oxide film or the protective film on the surface of the substrate 9 is etched. Thereafter, the substrate 9 is carried into the base film forming chamber 8, and a thin titanium film is formed as the base film. Then, the substrate 9 is carried into the sputtering chamber 4. Then, the bottom film forming step and the side film forming step are performed in the sputtering chamber 4 as described above. As a result, even when the substrate 9 has a hole having a high aspect ratio, a thin film having a sufficient thickness is formed on the bottom and side surfaces of the hole.

Thereafter, the substrate 9 is carried out of the sputtering chamber 4 and subjected to processing such as formation of an anti-reflection film and cooling if necessary. You. Thereafter, when a predetermined number of processed substrates 9 are accommodated in the post-lock cassette 51, the autoloader 7 operates to carry out the processed substrates 9 to the external cassette 62.

An example of film formation will be described. The apparatus of the present embodiment is suitable for use in forming a barrier film. Specifically, sputtering is performed using a target 42 made of titanium. First, an argon gas is introduced to form a titanium thin film, and then, a nitrogen gas is introduced to form a titanium nitride thin film while assisting the reaction between nitrogen and titanium. As a result, a barrier film structure in which the titanium nitride thin film is laminated on the titanium thin film is obtained.
In the above-described apparatus of the present embodiment, a certain merit may be obtained even if the sputtering DC power supply 421 and the sputtering high-frequency power supply 422 are simultaneously operated.
When these are operated at the same time, the high-frequency power source for sputtering 4
The negative DC voltage of the DC power supply for sputtering 421 is superimposed on the high frequency voltage of 22 and applied to the target 42. For example, when the above-described superposition is performed in the side-surface film forming process, a part of the sputtered particles can be ionized while performing low-pressure remote sputtering, and film formation can be performed while using ionized sputtering in an auxiliary manner. When the pressure is too low, the ionization efficiency is deteriorated, and when the pressure is high, the effect of the low-pressure remote sputtering is weakened. Therefore, it is difficult to select the pressure at this time.
It may be about 1.5 mTorr. In addition, when the superposition is performed in the bottom surface film forming step, ions are accelerated by the voltage of the DC power supply for sputtering 421 in addition to the self-bias voltage described above, so that there is an effect that the efficiency of overall sputtering is improved.

In the apparatus of this embodiment, the high-frequency power source 422 for sputtering is also used as the ionizing means.
The ionization may be performed using a power supply different from the power supply for sputtering. Specifically, the auxiliary power supply 472 provided to the auxiliary electrode 47 may be operated to perform ionization mainly using high-frequency energy from the auxiliary power supply 472.

Next, a second embodiment of the present invention will be described. FIG. 4 is a schematic plan view illustrating the configuration of the sputtering apparatus according to the second embodiment, and FIG.
FIG. 5 is a schematic sectional view taken along line XX of the sputtering apparatus shown in FIG. 4. In the above-described apparatus of the first embodiment, the bottom film forming step and the side film forming step are continuously performed in one sputtering chamber 4. However, it is possible to provide two sputtering chambers, perform the bottom surface film forming process in one of the sputtering chambers, and perform the side surface film forming process in the other sputtering chamber. The device shown in FIGS. 4 and 5 has this configuration. Specifically, as shown in FIG. 4, two of the plurality of processing chambers are sputtering chambers 81 and 82. One of the two sputtering chambers is a first sputtering chamber 81 for performing a bottom surface film forming process, and the other is a second sputtering chamber 82 for performing a side surface film forming process.

As shown in FIG. 5, the two sputter chambers 81 and 82 have substantially the same configuration as the sputter chamber of the first embodiment shown in FIG. That is, the first sputtering chamber 81 is provided with a first exhaust system 81 for exhausting the inside.
1, a first target 812 having a sputtered surface exposed inside, a first sputtering power supply 813 for sputtering the first target 812, a first gas introduction system 814 for introducing gas into the inside, A first substrate holder 815 for holding the substrate 9 at a predetermined position. The second sputtering chamber 82 includes a second exhaust system 821 for exhausting the inside, a second target 822 having a sputtered surface exposed inside, and a second sputtering power supply 823 for sputtering the second target 822. , A second gas introduction system 824 for introducing gas into the inside, and a second substrate holder 825 for holding the substrate 9 at a predetermined position inside.

The first sputtering power supply 813 is a high-frequency power supply similar to the sputtering high-frequency power supply 422 in the first embodiment. A matching device (not shown) is provided between the first sputtering power source 813 and the first target 812. The first substrate holder 815 is configured to hold the substrate 9 such that the TS distance is a short first distance. Further, the first sputtering chamber 81
Inside, an auxiliary electrode 817 similar to the auxiliary electrode 47 of the first embodiment is provided, and a substrate holder 815 is provided with an electric field setting means 818 similar to the electric field setting means 48 of the first embodiment. ing. On the other hand, the second sputtering power supply 823 of the second sputtering chamber 82 is a negative DC power supply similar to the sputtering DC power supply 421 in the first embodiment. The second substrate holder 825 is configured to hold the substrate 9 such that the TS distance is a short second distance.

In the apparatus according to the second embodiment having the above structure, the substrate 9 is formed in the first sputtering chamber 81 by ionization sputtering at a high film forming rate on the bottom surface of the hole. In this case, a film is formed at a high film forming rate on the side surface of the hole by low-pressure remote sputtering. Also in this case, as in the case of the first embodiment, it is possible to form a film with a sufficient thickness on the inner surface of a hole having an extremely high aspect ratio of 7 or more. Since the bottom film forming process and the side film forming process are continuously performed in a vacuum, the substrate 9 is not stained between both processes, and a high quality thin film can be formed. Also, the bottom film forming step and the side film forming step are performed in different sputtering chambers 81 and 82, so that the tact time can be shortened. Therefore, in the above-described first embodiment, when the processing in the sputtering chamber 4 among the processing chambers requires the longest time, the improvement in productivity can be expected according to the second embodiment. However, since the number of sputtering chambers is two, the cost of the apparatus is high. Conversely, the first embodiment described above is advantageous in terms of the cost of the device.

[0037]

Next, an example of the present invention will be described. First, the conditions common to both the bottom film forming step and the side film forming step are as follows.・ Substrate: 200 mm diameter silicon wafer ・ Hole: Opening diameter 0.4 μm, depth 2 μm, aspect ratio 5 ・ Target: Titanium 300 mm in diameter

The conditions of the bottom film forming step can be set as follows.・ Film forming pressure: 60 mTorr ・ Discharge gas: Argon or nitrogen ・ Gas flow rate: 60 cc / min ・ Sputter power supply: frequency 13.56 MHz, output 3 kW ・ Applied voltage to target; 300 V ・ TS distance: 90 mm ・ Substrate temperature; 350 ° C. Self-bias voltage of the substrate; 100 V Under the above conditions, a thin film can be formed on the bottom surface of the hole at a deposition rate of about 350 Å / min.
At this time, the bottom coverage ratio (the ratio of the film formation rate on the bottom surface of the hole to the surface outside the hole) is about 70%.

Further, the side face film forming step can be performed under the following conditions. -Deposition pressure: 0.3 mTorr-Discharge gas: Argon or nitrogen-Gas flow rate: 10 cc / min-Sputter power supply: -600 V-Power input to target: 12 kW-TS distance: 230 mm-Substrate temperature: 350 ° C According to the conditions, a thin film can be formed on the side surface of the hole at a film forming rate of about 700 angstroms per minute.
At this time, the side coverage ratio (the ratio of the film forming rate on the side surface of the hole to the surface outside the hole) is about 25%.

In each of the above embodiments and examples,
A thin film having a required thickness may be formed in a plurality of times instead of being formed in one bottom film forming step and one side film forming step. That is, for example, the side surface deposition process may be performed after the bottom surface deposition process, and this cycle may be repeated a plurality of times. In this manner, a structure is obtained in which the thin film formed in the bottom film forming step and the thin film formed in the side film forming step are alternately stacked. When there is a slight difference in characteristics between the thin film formed in the bottom film forming process and the thin film formed in the side film forming process, there is an advantage that the difference can be reduced and a uniform thin film can be formed as a whole.

[0041]

As described above, according to the method of claim 1 and the apparatus of claim 2, the bottom film forming step by ionization sputtering and the side film forming step by low-pressure remote sputtering are combined in a vacuum. Since the film is continuously formed, a film having a sufficient thickness can be formed even on the inner surface of a hole having an aspect ratio of 7 or more. Therefore, it is possible to provide a breakthrough for the production of next-generation devices having a line width of 0.18 μm or less. According to the apparatus of the third aspect, in addition to the effect of the second aspect, since only one sputtering chamber is required, the cost of the apparatus can be reduced. According to the fifth aspect of the present invention, in addition to the effect of the second aspect, the bottom surface forming step and the side surface forming step are performed in different sputtering chambers, so that the tact time is shortened and the productivity can be increased. there is a possibility. Further, according to the invention of claim 6, the conditions of the pressure and the TS distance in the bottom film forming step and the side film forming step are optimized, and the effect of claim 2 can be more reliably obtained.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a configuration of a sputtering apparatus according to a first embodiment belonging to the inventions of claims 2 and 3;

FIG. 2 is a schematic front view showing a configuration of a sputtering chamber 4 shown in FIG.

FIG. 3 is a diagram schematically illustrating an improvement in a side surface film forming speed.

FIG. 4 is a schematic plan view illustrating the configuration of a sputtering apparatus according to a second embodiment.

5 is a schematic cross-sectional view taken along line XX of the sputtering apparatus shown in FIG.

FIG. 6 is a diagram for explaining the technical difficulty of film formation for a hole having a high aspect ratio.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Separation chamber 11 Transfer robot 2 Preheat chamber 3 Pre-processing etching chamber 4 Sputter chamber 41 Exhaust system 42 Target 421 DC power supply for sputtering 422 High frequency power supply for sputtering 423 Switch circuit 43 Magnet mechanism 45 Substrate holder 451 Heater 44 Discharge gas introduction system 46 Distance changing mechanism 47 Auxiliary electrode 471 Capacitor 472 Auxiliary power supply 5 Load lock chamber 6 Gate valve 7 Autoloader 81 First sputter chamber 82 Second sputter chamber 9 Substrate

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[Procedure amendment]

[Submission date] February 17, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 2

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering method and apparatus for forming a predetermined thin film on the surface of a substrate by sputtering, and is particularly suitable for forming a film on the inner surface of minute holes formed on the surface of the substrate. And a sputtering method and apparatus.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008]

According to a first aspect of the present invention, there is provided a sputtering method for forming a predetermined thin film on the inner surface of a hole formed in a surface of a substrate by sputtering. The ionization of the sputter particles emitted from the target is performed, and an electric field having a component in the depth direction of the hole is set, and the ionized sputter particles are accelerated by the electric field to increase the film forming speed on the bottom surface of the hole. Bottom film forming step and a side film forming step of increasing the distance between the target and the substrate and lowering the pressure as compared to the bottom film forming step to increase the film forming rate on the side surface of the hole by performing sputtering. In this case, the bottom film forming step and the side film forming step are performed continuously in a vacuum. According to another aspect of the present invention, there is provided a sputtering apparatus for forming a predetermined thin film by sputtering on an inner surface of a hole formed on a surface of a substrate, wherein the sputtering apparatus includes an exhaust system. A gas introduction system for introducing a predetermined gas into the sputtering chamber, a target provided so that a surface to be sputtered is exposed in the sputtering chamber, a sputtering power supply for applying a voltage to the target and sputtering the target, Ionization means for ionizing sputter particles emitted from a target by sputtering, a substrate holder for holding a substrate at a predetermined position in a sputtering chamber, and acceleration of sputter particles ionized by the ionization means perpendicular to the substrate Field setting means for setting an electric field for the target, the target and the substrate And a control unit capable of controlling an exhaust system, a gas introduction system, an ionization unit, an electric field setting unit, and a distance change mechanism, and the control unit controls the ionization. When operating the means and the electric field setting means, the exhaust system and the gas introduction system are controlled so as to keep the pressure in the sputtering chamber at a high first pressure, and the distance between the target and the substrate is short. controls the distance changing mechanism so that the a distance, the ions
When the decomposing means and the electric field setting means are not operated, the exhaust system is controlled so that the pressure in the sputtering chamber is maintained at a second pressure lower than the first pressure, and the distance between the target and the substrate is set to a first value. The distance changing mechanism is controlled to be a second distance longer than the distance. According to a third aspect of the present invention, in the configuration of the second aspect, the sputter power supply is a high-frequency power supply, and the sputter particles are ionized by an electric field set by the high-frequency power supply. It is possible that the sputtering power supply is also used for the ionization means, further provided with a negative DC power supply for applying a negative DC voltage to the target, the voltage of the high frequency power supply and the negative DC power supply A switch circuit for selectively or simultaneously applying a voltage to the target. In order to solve the above problem, the invention according to claim 4 is a multi-chamber type sputtering apparatus in which at least one load lock chamber and a plurality of processing chambers are air-tightly connected around a separation chamber provided at the center. Wherein one of the plurality of processing chambers is a first sputter chamber, the other is a second sputter chamber, and the first sputter chamber is evacuated from the inside of the first sputter chamber. A first exhaust system, a first gas introduction system for introducing a predetermined gas into the first sputtering chamber, a first target provided in the first sputtering chamber so that the surface to be sputtered is exposed, A first sputtering power source for applying a voltage to one target to sputter the target; Ionizing means for ionizing sputter particles released from the slot, a first substrate holder for holding the substrate at a predetermined position in the first sputter chamber, and the sputter particles ionized by the ionizing means perpendicular to the substrate. An electric field setting means for setting an electric field for accelerating is provided, and the first exhaust system and the first gas introduction system can maintain the inside of the first sputtering chamber at a high first pressure. The first substrate holder holds the substrate so that the distance between the substrate and the first target is a short first distance, and the second sputter chamber is evacuated from the second sputter chamber. A second exhaust system, a second target provided such that the surface to be sputtered is exposed in the second sputtering chamber, and applying a voltage to the second target. A second sputtering power source for sputtering the two targets, and a second substrate holder for holding the substrate at a predetermined position in the second sputtering chamber are provided, and the second exhaust system is configured to pass the second sputtering chamber through the second sputtering chamber. The second substrate holder can maintain the substrate at a second pressure lower than the first pressure such that a distance between the substrate and the second target is a second distance longer than the first distance. It has a configuration to hold. In order to solve the above-mentioned problem, the invention described in claim 5 is based on claim 2,
In the configuration of 3 or 4, the first pressure is 10 mTo
rr to 100 mTorr and the second pressure is 1 mTorr or less, and the first distance is a distance within a range of 1 / 2.5 to 1/1 of the maximum width of the substrate, and The second distance has a configuration in which the distance is within a range of 1 to 1.5 times the maximum width of the substrate.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

The high-frequency sputtering will be described in more detail. A capacitance such as a capacitor is provided between the target 42 and the high-frequency power supply 422 for sputtering. When a high-frequency voltage is applied to the target 42 by the high-frequency power supply 422 for sputtering, a high-frequency discharge is generated in a space facing the target 42 to form plasma. At this time, when a high-frequency voltage is applied to the target 42 via the capacitance, electrons and positive ions in the plasma act on charging and discharging of the capacitance, and a negative self-bias voltage is applied to the substrate 9 due to a difference in mobility between the electrons and the positive ions. Occurs.
The space potential of the plasma is a positive potential of about 0 to 40 volts, and an electric field whose potential gradually decreases toward the target 42 is set between the plasma and the target 42 where the negative self-bias voltage is generated. Positive ions in the plasma are accelerated by the electric field, collide with the target 42, sputter the target 42, and the sputter discharge continues.
The DC power supply 421 for sputtering and the high-frequency power supply 422 for sputtering are connected in parallel to the target 42, and a switch circuit 423 is provided at a branch portion thereof. As can be seen from FIG. 2, the switch circuit 423
Are the DC power supply 421 for sputtering and the high frequency 42 for sputtering.
2 or both of them can be connected at the same time.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

When the sputtering high-frequency power supply 422 is operated while the sputtering gas is being introduced into the sputtering chamber 4 by the gas introduction system 44, as described above,
The target 42 is subjected to high frequency sputtering. At this time, the gas is turned into plasma by the high-frequency electric field to form plasma. Neutral sputtering particles emitted from the target 42, this plasma as it passes through, ionizing collide with ions and electrons in the plasma (hereinafter, ionized sputter particles) is adapted. The ionized sputtered particles are accelerated by the electric field set by the electric field setting means 48, are extracted from the plasma, fly at an angle more perpendicular to the substrate 9, and enter the substrate 9. Specifically, the electric field setting means 48 employs a high frequency power supply 481 which applies a high frequency voltage to the substrate holder 45 and applies a negative self-bias voltage to the substrate 9 by the interaction between the high frequency and the plasma. The high frequency power source 481, for example, of about 13.56MHz output 1 k W can be used. A matching device 482 is provided between the high frequency power supply 481 and the substrate holder 45. Further, when the substrate 9 and the substrate holder 45 are both conductors, a predetermined capacitor is provided in a high-frequency transmission path, and a high-frequency voltage is applied to the substrate 9 via the capacitor.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

When a high-frequency voltage is applied to the substrate 9 via a capacitance as in the case of the high-frequency power source 422 for sputtering described above, a self-bias voltage is generated in the substrate 9 and the substrate 9 is moved between the substrate 9 and the plasma toward the substrate 9. Thus, an electric field whose potential gradually decreases is set. The direction of the electric field is perpendicular to the substrate 9, and the positively ionized sputtered particles are accelerated by the electric field and vertically incident on the substrate 9. In the ionization sputtering, ions in the plasma change the direction of movement so as to follow a periodic change in the direction of the electric field. At this time, since the auxiliary electrode 47 is insulated from the ground potential by the capacitor 471 or is connected to the auxiliary power supply 472, an electric field is also set near the auxiliary electrode 47 . As a result, the ions move over a wide range, and there is a high probability that the ions collide with the neutral sputtered particles and are ionized. That is, the auxiliary electrode 47 has the function of increasing the ionization efficiency of sputtered particles.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction contents]

First, when performing the bottom surface deposition step, the inside of the sputtering chamber 4 is maintained at a high first pressure by controlling the pumping speed controller 412 and the flow rate controller 444. Further, the distance changing mechanism 46 moves the substrate holder 45 in advance so that the distance between the target 42 and the substrate 9 (hereinafter, referred to as TS distance) becomes a short first distance. In this state, the sputtering high-frequency power supply 422 and the electric field setting means 48 are operated to perform ionized sputtering. That is, as described above, the high-frequency sputtering power supply 422 performs high-frequency sputtering with the voltage applied to the target 42 and ionizes the sputtered particles in the plasma. Then, the ionized sputtered particles are drawn out by the electric field set by the electric field setting means 48 and vertically incident on the substrate 9. The sputtered particles are on the substrate 9
When the light is incident vertically, the sputtered particles can easily reach the bottom surface of the hole, so that film deposition on the bottom surface of the hole is promoted. That is, the film forming speed on the bottom surface of the hole increases. It should be noted that the pressure is reduced as described above and the TS distance is reduced.
Sputtering with a long separation is called "low pressure remote sputtering".
be called.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0025

[Correction method] Change

[Correction contents]

Next, a side face film forming step is performed. In particular,
The distance changing mechanism 46 is operated to move the substrate holder 45 in advance so that the TS distance becomes the second long distance. Further, the inside of the sputtering chamber 4 is kept at a low second pressure by controlling the pumping speed controller 412 and the flow rate controller 444.
In this state, the DC power supply 421 for sputtering is operated to perform DC sputtering. At this time, since the TS distance is long and the pressure is low, film deposition on the side surface of the hole is promoted, and sputtering with a high side surface deposition rate can be performed. After performing the sputtering for a predetermined time, the high-frequency power source 4 for sputtering is used.
22, the operation of the electric field setting means 48, the gas introduction system 44 and the like are stopped, and the substrate 9 is taken out of the sputtering chamber 4.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0030

[Correction method] Change

[Correction contents]

Thereafter, the substrate 9 is carried out of the sputter chamber 4 and subjected to processing such as formation of an anti-reflection film and cooling if necessary. Then, the substrate 9 is accommodated in the lock cassette 51 in the load lock chamber 5 by the transfer robot 11. You. After that , when a predetermined number of processed substrates 9 are stored in the cassette 51 inside the lock , the autoloader 7 operates to carry out the processed substrates 9 to the external cassette 62.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction contents]

The first sputtering power supply 813 is a high-frequency power supply similar to the sputtering high-frequency power supply 422 in the first embodiment. A matching device (not shown) is provided between the first sputtering power source 813 and the first target 812. The first substrate holder 815 is configured to hold the substrate 9 such that the TS distance is a short first distance. Further, the first sputtering chamber 81
Inside, an auxiliary electrode 817 similar to the auxiliary electrode 47 of the first embodiment is provided, and a substrate holder 815 is provided with an electric field setting means 818 similar to the electric field setting means 48 of the first embodiment. ing. On the other hand, the second sputtering power supply 823 of the second sputtering chamber 82 is a negative DC power supply similar to the sputtering DC power supply 421 in the first embodiment. The second substrate holder 825 is configured to hold the substrate 9 such that the TS distance is a long second distance.

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction contents]

[0041]

As described above, according to the method of claim 1 and the apparatus of claim 2, the bottom film forming step by ionization sputtering and the side film forming step by low-pressure remote sputtering are combined in a vacuum. Since the film is continuously formed, a film having a sufficient thickness can be formed even on the inner surface of a hole having an aspect ratio of 7 or more. Therefore, it is possible to provide a breakthrough for the production of the following next-generation devices linewidth 0.18 .mu.m. According to the apparatus of the third aspect, in addition to the effect of the second aspect, since only one sputtering chamber is required, the cost of the apparatus can be reduced. According to the fifth aspect of the present invention, in addition to the effect of the second aspect, the bottom surface forming step and the side surface forming step are performed in different sputtering chambers, so that the tact time is shortened and the productivity can be increased. there is a possibility. Further, according to the invention of claim 6, the conditions of the pressure and the TS distance in the bottom film forming step and the side film forming step are optimized, and the effect of claim 2 can be more reliably obtained.

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name] Explanation of sign

[Correction method] Change

[Correction contents]

[Description of Signs] 1 Separation chamber 11 Transfer robot 2 Preheat chamber 3 Pretreatment etching chamber 4 Sputter chamber 41 Exhaust system 42 Target 421 DC power supply for sputtering 422 High frequency power supply for sputtering 423 Switch circuit 43 Magnet mechanism 44 Gas introduction system 45 Substrate holder 451 Heater 46 Distance changing mechanism 47 Auxiliary electrode 471 Capacitor 472 Auxiliary power supply 5 Load lock chamber 6 Gate valve 7 Autoloader 81 First sputter chamber 82 Second sputter chamber 9 Substrate

Claims (5)

[Claims] 1. A sputtering method for forming a predetermined thin film on the inner surface of a hole formed on a surface of a substrate by sputtering, wherein a sputtered particle emitted from a target is ionized and a component is formed in a depth direction of the hole. An electric field to be set is set, and the distance between the target and the substrate is increased as compared with the bottom film forming step in which a film forming speed on the bottom surface of the hole is increased by accelerating the ionized sputter particles by this electric field. Includes a longer side and a lower pressure to perform a sputtering to increase the film forming rate on the side surface of the hole, and a side surface film forming step and a side surface film forming step are continuously performed in a vacuum. A sputtering method characterized by the above-mentioned. 2. A sputtering apparatus for forming a predetermined thin film by sputtering on an inner surface of a hole formed on a surface of a substrate, comprising: a sputter chamber provided with an exhaust system; and a gas for introducing a predetermined gas into the sputter chamber. An introduction system, a target provided in a sputtering chamber so that a surface to be sputtered is exposed, a sputtering power supply for applying a voltage to the target to sputter the target, and ionizing sputter particles emitted from the target by sputtering. Ionization means for holding a substrate in a predetermined position in a sputtering chamber, a substrate holder, an electric field setting means for setting an electric field for vertically accelerating sputter particles ionized by the ionization means to the substrate, and a target A distance changing mechanism for changing a distance between the substrate and the substrate; A gas system, a gas introduction system, an ionization unit, an electric field setting unit, and a control unit capable of controlling a distance changing mechanism are provided.The control unit is configured to operate the ionization unit and the electric field setting unit. Controlling the exhaust system and the gas introduction system so as to maintain the pressure in the sputtering chamber at a high first pressure, and controlling a distance changing unit so that the distance between the target and the substrate is a short first distance, When the ionization unit and the electric field setting unit are not operated, the exhaust system is controlled so as to maintain the pressure in the sputtering chamber at a second pressure lower than the first pressure, and the distance between the target and the substrate is reduced. A sputtering apparatus for controlling a distance changing means so as to be a second distance longer than the first distance. 3. The high frequency power supply according to claim 1, wherein the sputtering power supply is a high frequency power supply.
The sputter particles can be ionized by an electric field set by the high-frequency power supply, and the sputter power supply is also used as the ionization means, and further, a negative DC power supply for applying a negative DC voltage to the target 3. The switch according to claim 2, further comprising: a switch circuit configured to selectively or simultaneously apply a voltage of the high-frequency power supply and a voltage of the negative DC power supply to the target. Sputtering equipment. 4. A multi-chamber type sputtering apparatus in which at least one load lock chamber and a plurality of processing chambers are air-tightly connected around a separation chamber provided at a center, wherein the plurality of processing chambers are provided. One is a first sputtering chamber, and the other is a second sputtering chamber. The first sputtering chamber has a first exhaust system for exhausting the inside of the first sputtering chamber, and a first sputtering chamber. A first gas introduction system for introducing a predetermined gas into the first target, a first target provided such that a surface to be sputtered is exposed in a first sputtering chamber, and applying a voltage to the first target to sputter the target. The first sputter power source and the sputter particles emitted from the first target by sputtering are ionized. An ionization means for converting the ionization means, a first substrate holder for holding the substrate at a predetermined position in the first sputtering chamber, and an electric field for vertically accelerating the sputtered particles ionized by the ionization means toward the substrate. Electric field setting means is provided, the first exhaust system and the first gas introduction system can maintain a high first pressure in the first sputtering chamber, and the first substrate holder And holding the substrate so that the distance between the first target and the first target is a short first distance, the second sputtering chamber, a second exhaust system for exhausting the second sputtering chamber, a second exhaust system, A second target provided in the sputtering chamber so that the surface to be sputtered is exposed, and a second sputtering for applying a voltage to the second target to sputter the second target. A power supply and a second substrate holder for holding the substrate at a predetermined position in the second sputtering chamber are provided, and the second exhaust system is configured to supply a second pressure lower than the first pressure in the second sputtering chamber. It is possible to maintain the pressure, the second substrate holder is to hold the substrate so that the distance between the substrate and the second target is a second distance longer than the first distance. Sputtering equipment. 5. The method according to claim 1, wherein the first pressure is from 10 mTorr to 1 mTorr.
00 mTorr and the second pressure is 1 m
Torr or less, the first distance is a distance within a range of 1 / 2.5 to 1/1 of the maximum width of the substrate, and the second distance is 1 to 1.5 times the maximum width of the substrate. 5. The sputtering apparatus according to claim 2, wherein the distance is within the range.