JPH11307479A - High temperature reflow sputtering method and high temperature reflow sputtering apparatus - Google Patents

Abstract

(57) [Problem] To provide a high-temperature reflow sputtering technique capable of sufficiently filling a metal material into a hole even when a substrate is heated at a lower temperature. A distance changing mechanism (4) for changing a distance between a substrate (9) held by a substrate holder (44) and a target (42).
6, in the first step of the two-stage film formation, the distance between the substrate 9 and the target 42 is a first distance longer than the conventional distance,
In the second step, control is performed such that the second distance is shorter than the first distance. Since the thick base thin film 93 is formed on the inner surface of the hole 90 in the first step, the metal material can be sufficiently embedded in the hole 90 even if reflow is performed at a relatively low temperature in the second step. In addition, 1
Impurity gas such as water condenses on the panel 12 cooled to 30K to 50K, and is prevented from adhering to the substrate 9 in the separation chamber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-temperature reflow sputtering technique for embedding a metal material in a hole formed on the surface of a substrate.

[0002]

2. Description of the Related Art A sputtering technique for forming a predetermined thin film on the surface of a substrate by sputtering a target is widely used in the production of semiconductor integrated circuits. A substrate such as a semiconductor wafer on which a thin film is formed by sputtering often has fine holes, and it is necessary to form a thin film in the fine holes. For example, 256 megabit to 1 gigabit DRAM (Dynamic Random Accesses)
s Memory), it becomes necessary to form a film in a groove or a hole having a width or diameter of about 0.25 μm to 0.18 μm (collectively referred to as a hole in this specification) according to a design rule.

As a technique utilizing sputtering for film formation in such a hole, a high-temperature reflow sputtering technique of embedding a metal material in the hole has been conventionally known. FIG. 6 is a front view showing a schematic configuration of a conventional high-temperature reflow sputtering apparatus for performing such high-temperature reflow sputtering. The high-temperature reflow sputtering apparatus shown in FIG. 6 includes a sputtering chamber 4 provided with an exhaust system 41, a target 42 provided in the sputtering chamber 4 so as to expose a surface to be sputtered, and a sputtering system for sputtering the target 42. Power supply 43
The substrate 9 is positioned at a predetermined position in the sputtering chamber 4 where the material of the target 42 released by sputtering reaches.
, A discharge gas introduction system 45 for introducing a predetermined sputter discharge gas into the sputtering chamber 4, and a heater provided in the substrate holder 44 to heat the substrate 9 to a predetermined temperature. 441 are provided.

The target 42 is made of a metal such as aluminum, and is attached to the sputtering chamber 4 via an insulating material 421. The sputtering power supply 43 is configured to apply a high negative voltage to the target 42. A sputter discharge gas such as argon is introduced into the sputter chamber 4 by a discharge gas introduction system 45, and the target 4
When a negative high voltage is applied to 2, a DC electric field is set between the substrate holder 44 which is a ground potential and the wall of the sputtering chamber 4, and this DC electric field causes sputter discharge. Particles of the metal material (usually in an atomic state;
The sputtered particles reach the substrate 9 and deposit a thin film of a predetermined metal material. In addition, target 4 in this device
The distance between 2 and substrate 9 is 60 mm. On the other hand, the heater 44
The heat from 1 is applied to the substrate 9 via the substrate holder 44, and the substrate 9 is heated to a predetermined temperature. The thin film deposited on the surface of the substrate 9 is reflowed (fluidized) by the heat of the substrate 9 and flows into fine holes. As a result, the metal material is buried in the holes, and the surface of the substrate 9 is flattened.

[0005]

In the above-mentioned conventional high-temperature reflow sputtering, the substrate is heated from 400.degree.
It is heated to about 00 ° C. The higher the temperature of the substrate, the higher the fluidity of the metal material, and the easier it is to bury the metal material in the holes. However, by performing the treatment at such a high temperature, the crystal growth of the metal material is accelerated, and the grain size is increased. When the grain size is large, there is a problem that unevenness is formed on the surface of the substrate, and alignment in photolithography in a later step becomes difficult. Also, as the grain size increases, the problem of electromigration also becomes apparent.

In the manufacture of a device having a multilayer wiring structure, an aluminum film may be already formed as a first-layer wiring on a silicon substrate. In this case, when high-temperature reflow sputtering of aluminum is performed for the wiring of the second layer, the temperature of 400 ° C. to 5 ° C. at the interface between the already formed aluminum film of the first layer and silicon is obtained.
These melt at a temperature of about 00 ° C. Then, when cooled, aluminum and silicon are eutectic, and "disappearance of aluminum" which becomes an aluminum-silicon alloy occurs.
Such loss of aluminum leads to defects and defects such as disconnection of circuits and increase in wiring resistance.

In order to avoid such a problem, high-temperature reflow sputtering at 400 ° C. or less can be considered. However, when high-temperature reflow sputtering is performed at such a low temperature of 400 ° C. or lower, for example, about 200 ° C., a metal material cannot be sufficiently reflowed, so that a cavity called a void is generated in a hole. If a void is formed in the hole, the circuit may be defective or defective, such as disconnection or an increase in wiring resistance.

The invention of the present application has been made to solve the above-mentioned problems, and provides a technique of high-temperature reflow sputtering that can sufficiently bury a metal material in a hole even when a substrate is heated at a lower temperature. It is intended to be.

[0009]

According to a first aspect of the present invention, there is provided a thin film made of a metal material by sputtering a metal target on a surface of a substrate on which fine holes are formed. Forming a high temperature reflow sputtering method of heating the substrate to reflow the thin film and bury the metal material in the hole, the first step of creating a base thin film of the metal material on the side and bottom surfaces of the hole, After the first step, a second step of burying the metal material in the hole by further depositing and reflowing a thin film of the metal material, and in the first step, the target and the substrate Film formation is performed with a long first distance, and in the second step, film formation is performed with a second distance shorter than the first distance between the target and the substrate. With a cormorant configuration. According to another aspect of the present invention, a thin film of a metal material is formed by sputtering on a surface of a substrate having fine holes formed thereon, and the substrate is heated to reflow the thin film. A high-temperature reflow sputtering apparatus for embedding a metal material into a sputtering chamber having an exhaust system, a target provided to expose a surface to be sputtered in the sputtering chamber, and a sputtering power supply for sputtering the target. A substrate holder for holding the substrate at a position where the material of the target released by sputtering reaches, a heater for heating the substrate held by the substrate holder, a distance changing mechanism for changing the distance between the target and the substrate, A control unit for controlling a distance changing mechanism, wherein the control unit is configured to The distance between the substrate and the first step of forming the base thin film of the metal material on the side and bottom surfaces of the hole is a long first distance, and after the first step, the thin film of the metal material is further deposited. In the second step of embedding the metal material in the hole by reflow, the distance changing mechanism is controlled to be a second distance shorter than the first distance. According to a third aspect of the present invention, in order to solve the above-mentioned problem, in the configuration according to the second aspect, a separation chamber provided at the center, a load lock chamber air-tightly connected around the separation chamber, and a plurality of processing units are provided. A load lock chamber is a chamber in which the substrate temporarily stays when the substrate is taken in and out with the atmosphere, and one of a plurality of processing chambers is the sputtering chamber. In the separation chamber, a transfer mechanism for transferring the substrate between the chambers is provided, and further, the separation chamber has a panel provided so that the surface is exposed to the internal space of the separation chamber. , 13 panels
And a refrigerator that cools to 0K to 50K and condenses the impurity gas in the separation chamber on the surface of the panel. According to a fourth aspect of the present invention, the panel is provided such that the surface is located near a boundary between the separation chamber and the load lock chamber. It has a configuration that it is. According to a fifth aspect of the present invention, in order to solve the above-mentioned problem, in the configuration according to the third or fourth aspect, one of the plurality of processing chambers includes a preheater for heating a substrate before processing in a sputtering chamber. A chamber,
The panel has a configuration in which the surface is provided near a boundary between the separation chamber and the preheat chamber. Also,
In order to solve the above-mentioned problem, the invention according to claim 6 is to form a thin film of a metal material by sputtering on a surface of a substrate having fine holes formed on the surface, and heat the substrate to reflow the thin film to form a metal in the hole. A high-temperature reflow sputtering apparatus for embedding a material, comprising: a separation chamber provided in the center; a load lock chamber and a plurality of processing chambers that are airtightly connected around the separation chamber; and the load lock chamber is connected to the atmosphere. A transfer mechanism for transferring a substrate between chambers is provided in the separation chamber. The transfer mechanism is provided in the separation chamber. One is a sputter chamber, and each of these two sputter chambers Are located at a position where the exhaust system for exhausting the inside, a target provided so as to expose the surface to be sputtered inside, a sputtering power supply for sputtering the target, and a target material discharged by sputtering reach. A substrate holder for holding the substrate is provided, and the substrate holder in one of the sputtering chambers holds the substrate so that the distance between the target and the substrate becomes a long first distance, and the other The substrate holder in the sputtering chamber is for holding the substrate such that the distance between the target and the substrate is a second distance shorter than the first distance, and the other sputtering chamber is held by the substrate holder. It has a heater for heating the substrate.

[0010]

Embodiments of the present invention will be described below. FIG. 1 is a schematic plan view illustrating the configuration of a high-temperature reflow sputtering apparatus according to an embodiment of the present invention. The high-temperature reflow sputtering apparatus shown in FIG. 1 is a multi-chamber type apparatus, and includes a separation chamber 1 disposed in the center and a plurality of processing chambers 2, 3, 4, 8, and hermetically connected around the separation chamber 1. The chamber arrangement is composed of 81 and two load lock chambers 5. Each of the chambers 1, 2, 3, 4, 5, 8, and 81 is provided with a dedicated or combined exhaust system (not shown), and is configured to exhaust 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, 8 and 81, 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 moves the substrate 9 from the external cassette 62 on the atmosphere side.
Are taken out one by one and housed in a lock cassette 51 in the load lock chamber 5.

A plurality of processing chambers 2, 3, 4, 8, 8
One is a sputter chamber 4 in which holes on the surface of the substrate 9 are filled by high-temperature reflow sputtering.
It is. In addition, a preheat chamber 2 for preheating the substrate 9 before sputtering, a pretreatment etching chamber 3 for performing pretreatment etching for removing a natural oxide film or a protective film on the surface of the substrate 9 before sputtering, This is a base film forming chamber 8 for forming a base film before film formation by reflow sputtering.

FIG. 2 shows the high-temperature reflow sputtering shown in FIG.
Front cross section of sputter chamber 4 in ring device
It is a schematic diagram. Principal parts of sputtering equipment using FIG.
A description will be given of the sputter chamber 4 which forms Spatter
The chamber 4 is an airtight container equipped with a gate valve 6,
It is electrically grounded. And the sputter chamber
The inside of -4 is 10 ^-8-10^-9Torr
It is configured to be evacuated to a degree. The exhaust system 41 is
Multistage vacuum pumps such as turbo molecular pumps and cryopumps
Equipped with a pump, and an exhaust speed (not shown) such as a variable orifice.
A degree adjuster is provided. In sputter chamber 4
Is a discharge gas guide for introducing a predetermined sputter discharge gas.
An inlet system 45 is provided, and the sputtering rate of argon or the like is reduced.
High gas can be introduced into the chamber at a predetermined flow rate
It has become. Specifically, the discharge gas introduction system 45 includes:
Gas cylinder containing gas for sputter discharge such as argon
451, the sputter chamber 4 and the gas cylinder 451
A connecting pipe 452 and a valve 453 provided on the pipe 452
And a flow controller 454.

A target 42 is provided in the sputtering chamber 4 so as to expose the surface to be sputtered. The target 42 is formed of a metal material, for example, aluminum to be embedded in a hole on the surface of the substrate 9. The target 42 is attached to the sputter chamber 4 via a target holder 421 and an insulator 422 so as to hermetically close the upper opening of the sputter chamber 4. A sputtering power supply 43 for sputtering the target 42 is connected to the target 42. The sputtering power supply 43 is configured to apply a negative DC voltage of about 400 to 600 V to the target 42. When the sputtering power supply 43 is operated in a state where the gas is introduced by the discharge gas introduction system 45, a discharge is generated in the gas and the target 42 is sputtered. When sputter discharge is maintained only by ionization of sputter particles released from the target 42, gas may not be introduced in some cases.

Behind the target 42, a magnet mechanism 48
Is provided. The magnet mechanism 48 achieves magnetron discharge. Specifically, the magnet mechanism 48
Are a center magnet 481, a peripheral magnet 482 surrounding the center magnet 481, a center magnet 481 and a peripheral magnet 48.
2 is fixed to the plate-shaped yoke 483. Between the center magnet 481 and the peripheral magnet 482, an arch-shaped magnetic force line 484 penetrating the target 42 is set. Electrons are confined in a region surrounded by the lines of magnetic force 484 and the surface to be sputtered of the target 42, and neutral gas molecules are ionized with high efficiency. For this reason, the sputter discharge is efficiently maintained, a large number of sputter particles are emitted, and a high film formation rate can be obtained. The direction of the DC electric field set by the sputtering power supply 43 is perpendicular to the surface of the target 42 to be sputtered. Therefore, the arc-shaped magnetic field lines 48
The magnetic field and the electric field are orthogonal to each other near the top of 4, and a magnetron discharge is achieved. That is, the electrons perform magnetron motion and circumnavigate around the central axis of the target 42 to further improve sputter discharge efficiency.

In the sputtering chamber 4, a substrate holder 44 for mounting the substrate 9 at a position where the material of the target 42 released by the sputtering reaches is provided. Inside the substrate holder 44, a heater 441 of a resistance heating type or the like is embedded. Heater 441
Alternatively, a radiant heater may be provided in the substrate holder 44. The substrate holder 44 has an electrostatic attraction mechanism 49 for bringing the substrate 9 into good thermal contact.
Is provided. The electrostatic attraction mechanism 49 mainly includes an attraction electrode 492 embedded in a dielectric block 491 provided as a part of the substrate holder 44 and an attraction power supply 493 for applying a DC voltage between the attraction electrodes 492. It is configured.

The dielectric block 491 is joined to the substrate holder body 44 with good adhesion. The surface of the dielectric block 491 is a mounting surface on which the substrate 9 is mounted, and a plurality of recesses 494 are formed on the surface. A pressurizing gas introduction system 495 for introducing a pressurizing gas is connected to the concave portion 494. Power supply 4 for suction
93 is configured to apply a voltage of, for example, about 200 to 800 V between the pair of suction electrodes 492. This voltage causes dielectric polarization in the dielectric block 491 and induces static electricity on the surface. The substrate 9 is electrostatically attracted to the dielectric block 491 by the static electricity. As a result, the adhesion of the substrate 9 to the substrate holder 44 is improved, and the heat from the heater 441 is efficiently transmitted to the substrate 9. Further, as a result of the gas being introduced into the concave portion 494 by the pressurizing gas introducing system 495, the pressure in the concave portion 494 increases. For this reason, the heat transfer efficiency between the substrate holder 44 and the substrate 9 is improved, and the heating efficiency of the substrate 9 is increased. Pressurizing gas introduction system 495
Is designed to introduce a gas such as helium having a good heat transfer efficiency. The major feature of the apparatus of this embodiment is that the substrate holder 44 is provided with a distance changing mechanism 46 for changing the distance between the target 42 and the substrate 9. Specifically, the substrate holder 44 is supported by a support 442. Distance changing mechanism 46
Is a holding plate 463 holding the lower end of the support 442,
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 prevented from rotating by a rotation stopper (not shown), it only moves up and down. As a result, the support 442 is supported via the holding plate 463 fixed to the driven body 464.
Moves up and down, and accordingly, the substrate holder 44 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 44 and the target 42 can be changed by the operation of the distance changing mechanism 46 as described above. Has become.

The apparatus of this embodiment is provided with a control unit (not shown) for controlling the entire apparatus. The control unit is configured to control each component such as the distance changing mechanism 46 and the sputtering power supply 43. The distance changing mechanism 46 in the present embodiment and a control unit (not shown) for controlling the distance changing mechanism 46 are provided in association with the apparatus of the present embodiment performing two-stage film formation. The two-stage film formation is a technique found by the inventor of the present application in an attempt to lower the substrate temperature (hereinafter, the film formation temperature) when performing high-temperature reflow sputtering.
This point will be described with reference to FIGS. FIG. 3 is a diagram showing a problem when the film formation temperature is lowered without performing the two-stage film formation, and FIG. 4 is a diagram showing a film formation state when the two-stage film formation is performed.

First, a case where the two-stage film formation is not performed will be described with reference to FIG. As described above, high-temperature reflow sputtering deposits a thin film on the surface of the substrate 9 in which the holes 90 are formed by sputtering.
Is heated to reflow the thin film and bury it in the hole. At this time, the reflowed thin film (hereinafter, reflow thin film) 91 tends to stay at the edge of the opening of the hole 90 due to the influence of interfacial tension and the like. In this case, as shown in FIG. 3A, the reflow thin film 91 is formed as shown in FIG.
The reflow thin film 91 stays on the edge of the opening so as to rise. Further, a thin film is initially deposited on the inner surface of the hole 90, but as a result of the substrate 9 being exposed to a high temperature, the thin film is interrupted on the side surface of the hole 90. Then, even if the deposition amount of the thin film is increased by continuing the sputtering, only the reflow thin film 91 which rises at the edge of the opening and stays increases, and does not flow into the hole 90. As a result, the opening is closed by the reflow thin film 91, and apparently, the hole 9 is formed.
Even if it seems that the embedding of the metal material into the hole 0 has been completed, a cavity 92 called a void is generated in the hole 90 as shown in FIG. When the void 92 is formed, when the metal material is buried as the wiring, the wiring is disconnected, leading to a fatal element defect.

When the film formation temperature is increased to a certain degree, the fluidity of the reflow thin film 91 is increased, so that the reflow thin film 91 staying at the edge of the opening of the hole 90 can be flowed into the hole 90, whereby the void Can be suppressed to some extent. However, increasing the film formation temperature causes the above-described problems such as an increase in grain size. In order to prevent the void 92 from being generated, it is only necessary to prevent the reflow thin film 91 from staying at the edge of the opening of the hole 90. The stagnation of the reflow thin film 91 is caused by the interfacial tension of the reflow thin film 91 itself, but it is considered that the influence of the affinity (wetting property) with the base surface is large. That is, the reflow thin film 91 is made of a metal such as aluminum, and the surface of the hole 90 is made of a different material such as silicon or silicon oxide. It generally has low affinity for surfaces of different materials and is less likely to flow along the surface. If the reflow thin film 91 flows on the surface of the same material, the affinity is high, so that the stay at the edge of the opening of the hole 90 should be reduced.

In order for the reflow thin film 91 to flow on the surface of the same material, a thin film of the same material may be formed on the surface in the hole 90 in advance. From such a concept, the inventor of the present application divides the process into two steps of high-temperature reflow sputtering, and first forms a thin film 93 of a metal material thinly on the inner surface of the hole 90 as shown in FIG. (Hereinafter, the film formed in this step is referred to as “base thin film”), and after the first step, FIG.
As shown in (C), a thin film of a metal material is further deposited, and the temperature of the substrate 9 is increased to cause reflow, whereby the holes 9 are formed.
Thus, a two-step film forming method for performing a second step of embedding a metal material in the metal layer 0 has been completed. In the first step, it is important to lower the film forming temperature so that the deposited base thin film 93 does not reflow. If the film formation temperature is increased to such an extent that the base thin film 93 reflows, FIG.
In the same manner as shown in FIG.
Is interrupted. If a break occurs, the reflow thin film 91 must flow over the base surface of the hole 90, so that the fluidity is reduced and voids are likely to be generated.

A major feature of the apparatus of this embodiment is that, in the first step of the two-stage film formation, the distance between the target 42 and the substrate 9 (hereinafter, referred to as TS distance) is longer than the conventional distance. Is a point. Specifically, the control unit operates the motor 462 of the distance changing mechanism 46 to control the distance between the substrate holder 44 and the target 42 to be a long first distance in the first step, and to control the second distance. In the process, the distance between the substrate holder 44 and the target 42 is controlled to be a second distance shorter than the first distance.

The situation when the TS distance is changed will be described with reference to FIG. FIG. 5 is a schematic diagram when the TS distance is changed. When the distance between the target 42 and the substrate 9 is increased from L1 to L2, the area of the sputtering target surface of the target 42 that can be seen from one point P in the hole 90 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 sputtered particle emission area that can reach one point P in the hole.
In the case of L2, the amount of sputtered particles reaching the point P is larger in the case of L2, and the film forming speed is higher. The same applies to other points in the hole 90. When the TS distance increases, the amount of sputtered particles reaching the point increases, and the film forming speed at that point increases. That is, by increasing the TS distance, the film forming speed on the inner surface of the hole 90 can be increased.

In the present embodiment, from the above viewpoint, the TS distance is increased in the first step to increase the film forming rate on the inner surface of the hole 90. When the deposition rate is increased, the base thin film 93 can be formed thick in the first step. According to the study of the inventor, it has been found that, when the thickness of the base thin film 93 is increased, even if the treatment is performed at a lower temperature in the second step, the filling can be performed without generating voids.
For example, in the case where aluminum is embedded in a hole having an aspect ratio of 3, in the first step, if the base thin film 93 is formed on the inner surface (side surface and bottom surface) of the hole 90 with a thickness of about 300 Å, the second Even when the substrate 9 was reflowed while heating the substrate 9 at a relatively low temperature of 380 ° C. while depositing a thin film in the process, generation of voids was not observed.

Although the reason why the film formation temperature can be lowered as described above cannot be generally stated, it is presumed that the fluidity of the reflow thin film 91 in the second step depends on the thickness of the base thin film 93. You. That is, it is presumed that the thicker the base thin film 93 serving as the base, the easier the reflow thin film 91 flows on. When the base thin film 93 is thin, when the substrate 9 is heated in the second step, the base thin film 93 flows before the reflow thin film 91 flows.
It is presumed that the interruption as shown in FIG.

In any case, in the apparatus of this embodiment,
Since the thick TS base film 93 is formed on the inner surface of the hole 90 by increasing the TS distance in the first step, high-temperature reflow sputtering can be performed at a relatively low temperature in the second step. It is not so preferable to increase the TS distance in the second step. This is because, when the TS distance is increased, the amount of sputter particles that reach the substrate 9 among the sputter particles emitted from the target 42 decreases, so that there is a problem that the efficiency of the entire film formation is reduced. In the second step, since the thin film is reflowed so as to be embedded in the hole 90, it is not necessary to increase the film forming speed in the hole 90 as in the first step. It is not preferable to unnecessarily lengthen the TS distance to lower the efficiency of film formation.

In the first step, it is preferable that the pressure in the sputtering chamber 4 during the film formation (hereinafter referred to as the film formation pressure) is lower than that of ordinary sputtering. When the pressure is high, the number of gas molecules existing in the sputter particle flight space from the target 42 to the substrate 9 is large, so that most of the sputter particles emitted from the target 42 are emitted and scattered by the gas molecules. Although many sputtered particles can reach the surface of the substrate 9 other than the holes 90 even if they are scattered, if the scattering of sputtered particles is large, the amount of sputtered particles that can reach the inside of the hole 90 decreases. As a result, the film forming speed on the inner surface of the hole 90 is relatively reduced. Therefore, in the first step, the film forming pressure is set lower than usual so that the sputtered particles flying toward the hole 90 are not scattered. Thereby, the film forming speed on the inner surface of the hole 90 is relatively increased, and a thick base thin film 93 can be formed on the inner surface of the hole 90. Specifically, in the first step, 1 mTo
It is preferable to set the film formation pressure to rr or less.

The operation in the sputtering chamber 4 will be described, including the above-mentioned two-stage film formation. The substrate 9 is carried into the sputtering chamber 4 and placed on the substrate holder 44. The inside of the sputtering chamber 4 is 10 ^-8
The gas is exhausted to about -10 ^-9 Torr, and in this state, a sputter discharge gas is introduced into the sputter chamber 4 by the discharge gas introduction system 45. By controlling an unillustrated evacuation rate adjuster of the evacuation system 41 and a flow rate adjuster 454 of the discharge gas introduction system 45, the inside of the sputter chamber 4 is formed at a deposition pressure of 0.8 to 1.5 mTorr in the first step. Pressure.

Then, the sputtering power supply 43 is operated, and the sputtering in the first step is performed. At this time, as described above, the control unit (not shown) operates the distance changing mechanism 46 to preliminarily position the substrate holder 44 at the predetermined lowering position, thereby increasing the TS distance. In addition, the substrate holder 44
Although the heater 441 inside is always operating, the electrostatic attraction mechanism 49 and the pressurizing gas introduction system 495 are not operated. Therefore, the efficiency of heat transfer from the heater 441 to the substrate 9 is low, and the temperature of the substrate 9 is maintained at a low temperature of about 100 to 150 ° C. By the sputtering in the first step, the base thin film 93 is formed as described above. The thickness of the base thin film 93 is about 200 to 400 angstroms. In the first step, the sputtering power supply 43
The input power to the target 42 by the above is about 18 to 20 kW, which is higher than usual. This is for compensating for a decrease in the overall film forming efficiency due to the increase in the TS distance, and for completing the film forming in a short time before the substrate 9 is heated by the heater 441.

Next, the second step is performed. That is, the control unit (not shown) operates the distance changing mechanism 46 to operate the substrate holder 4.
4 is positioned at a predetermined ascending position to shorten the TS distance. Almost at the same time, the electrostatic adsorption mechanism 49 and the pressurizing gas introduction system 49
5 is operated to increase the efficiency of heat transfer from the substrate holder 44 to the substrate 9 to increase the temperature of the substrate 9. Then, the sputtering is continued by operating the sputtering power supply 43,
A thin film is further deposited on the base thin film 93. The deposited or accumulating thin film is reflowed by the heat of the substrate 9 to become a reflow thin film 91, and flows into the inner surface of the hole 90. As a result, the metal material is embedded in the hole 90. In the second step, the power supplied to the target 42 by the sputtering power supply 43 is lower than that in the first step and is about 2 to 4 kW. This is based on the fact that it is better to deposit a thin film little by little and reflow the film without increasing the film forming speed too much, so that the filling characteristics in the hole 90 are better. Further, when shifting from the first step to the second step, the power may be reduced after the operation of the sputtering power supply 43 is temporarily stopped, or the power may be reduced without stopping the operation.

Next, returning to FIG. 1, another configuration of the high-temperature reflow sputtering apparatus of the present embodiment will be described.
The pretreatment etching chamber 3 shown in FIG. 1 is configured to etch the substrate 9 prior to film formation 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. Further, the pre-heat chamber 2 has a substrate 9 prior to film formation.
Is heated to 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. Preheat chamber 2
Inside, a heat stage (not shown) that is heated and maintained at a predetermined temperature is provided. The substrate 9 is placed on this heat stage and is preheated by being heated to a predetermined temperature. The base film forming chamber 8 forms a titanium thin film as a base film before high-temperature reflow sputtering. The base film forming chamber 8 is configured to form the base film by sputtering, and has substantially the same configuration as the sputter chamber 4 shown in FIG. 2 except that a target made of titanium is provided.
In some cases, an anti-reflection film is formed on the high-temperature reflow sputtering film formed in the sputtering chamber 4, and in this case, one of the other processing chambers 81 is an anti-reflection film forming chamber. . The antireflection film forming chamber is configured to form a titanium nitride thin film as an antireflection film by sputtering.

In the separation chamber 1,
As described above, the exhaust system (not shown) is provided. This exhaust system is an exhaust system equipped with a cryopump and the like.
It is configured to be able to exhaust to about ^-8 to 10 ^-9 Torr. Such an exhaust keeps the atmosphere in the separation chamber 1 clean.
However, in order to maintain the quality of high-temperature reflow sputtering sufficiently high, the apparatus of the present embodiment further includes another exhaust system in the separation chamber 1.

In the above-described apparatus according to the present embodiment, the substrate 9 is transferred to the processing chambers 2, 3, 4, 8 and 81 via the separation chamber 1. At this time, if there is an impurity gas in the separation chamber 1, the impurities adhere to the surface of the substrate 9. Then, there is a problem that high-temperature reflow sputtering in the sputtering chamber 4 cannot be sufficiently performed due to the attached impurities. More specifically, when water molecules adhere to the surface of the substrate 9, there is a problem in that, when the film is formed in the sputtering chamber 4, the adhesion of the thin film is impaired or the thin film is denatured such as being oxidized. is there. Further, water molecules evaporate rapidly due to the heat applied to the substrate 9 during the film formation in the sputtering chamber 4, so that irregularities are formed on the surface of the base thin film 93 by foaming or the like, or holes are formed in the base thin film 93. Sometimes. If such uneven holes are formed, the reflow thin film 91 may not flow well, which may cause voids.

In order to prevent the above problem, the apparatus according to the present embodiment includes a panel 12 provided so as to be exposed in the internal space of the separation chamber 1, and a panel 1.
And a refrigerator 13 for cooling impurity gas in the separation chamber 1 to condense on the surface of the panel 12.

The panel 12 is a member made of a material having high heat conductivity such as copper, and has a shape obtained by bending a belt-like member into an arc shape as shown in FIG. As can be seen from FIG. 2, the panel 12 is in a horizontal posture, and its surface is exposed inside the separation chamber 1. In the case where the panel is made of copper, a plated nickel or the like is used to prevent corrosion of the surface. Further, as can be seen from FIG. 1, the panel 12 is located near the boundary between the two load lock chambers 5 and the preheat chamber 2.

The refrigerator 13 is provided outside the separation chamber 1. As the refrigerator 13, for example, CRC420 manufactured by Anelva Co., Ltd. can be used. Refrigerator 1
The panel 3 and the panel 12 are connected by a heat conducting block 14 provided to penetrate the wall of the separation chamber 1. The heat guide block 14 is formed of a material having high thermal conductivity such as copper, so that cold generated by the refrigerator 13 is efficiently transmitted to the panel 12. Further, a heat insulating material (not shown) is provided between the heat guide block 14 and the wall of the separation chamber 1 so that the cold generated by the refrigerator 13 is not transmitted to the wall of the separation chamber 1.

Although the interior of the separation chamber 1 is evacuated by the above-mentioned exhaust system (not shown), it is still inevitable that some impurity gas remains. Refrigerator 13
When the panel 12 is cooled to a predetermined temperature by the cold generated by the above, the impurity gas remaining in the separation chamber 1 condenses on the panel 12. Therefore, the adhesion of the impurity gas to the surface of the substrate 9 is suppressed. When the amount of condensed impurity gas on the panel 12 is increased, the temperature of the surface of the panel 12 is not sufficiently lowered and the efficiency of condensing the impure gas is lowered. Do. The reproduction operation is performed while the operation of the apparatus is stopped. Specifically, the panel 12 is heated while the inside of the separation chamber 1 is exhausted at a high speed by an exhaust system (not shown). When the temperature of the panel 12 rises to some extent,
The condensed impurity gas is discharged into the separation chamber 1 and discharged from the separation chamber 1 by an exhaust system (not shown). Then, the surface of the panel 12 becomes an original clean surface free of impurity gas. After the inside of the separation chamber 1 is again evacuated to a high vacuum, the operation of the apparatus is restarted.

To what extent the panel 12 is cooled
This is important because it directly affects which residual gas is condensed. In the present embodiment, the refrigerator 13 includes the panel 12
It cools to about 0K to 50K. This cooling temperature is set so as to mainly condense water molecules in the separation chamber 1 as impurity gas. This is because, as described above, the presence of water molecules is a particular problem in high-temperature reflow sputtering. In order to adsorb this water molecule, it is desirable to set it to 130K or less.

The cooling temperature of the panel 12 should be set so as not to condense even the processing gas (process gas) introduced into each of the processing chambers 2, 3, 4, 8, and 81. The pressure in each of the processing chambers 2, 3, 4, 8, and 81 is determined by the flow rate of the process gas and the effective pumping speed by the pumping system. This is because the pressure in the chamber becomes unstable. Further, if the panel 12 adsorbs not only moisture but also process gas, the amount of gas condensed on the panel 12 increases in a short period of time, so that the panel 12 must be regenerated frequently and the productivity decreases. Cause. Nitrogen or argon is often used as a process gas, and in order to prevent condensation, the cooling temperature of the panel 12 is preferably set to 50K or higher. Therefore, the panel 12 is set to 130K-5
The point is to control the temperature within the range of 0K.

The fact that the surface (condensing surface) of the panel 12 is located near the load lock chamber 5 and the preheat chamber 2 is significant from the viewpoint of removing the water molecules. That is, the water molecules remaining in the separation chamber 1 enter from the atmosphere side via the load lock chamber 5 or are released from the substrate 9 at the time of preheating in the preheat chamber 2 and are separated from the preheat chamber 2 by the separation chamber 1. Often entered. Water molecules rarely enter from other chambers. Therefore, the configuration in which the surface of the panel 12 is located near the load lock chamber 5 and the preheat chamber 2 is significant in that the impurity gas is condensed only in a necessary place without increasing the surface of the panel 12 and deteriorating thermal efficiency. There is.

Next, the overall operation of the high-temperature reflow 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. Substrate 9 carried into cassette 51 inside lock
Is first loaded into the preheat chamber 2 by the transfer robot 11 provided in the separation chamber 1. Substrate 9 carried into preheat chamber 2
Is mounted 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. Then, the substrate 9
Is carried into a base film forming chamber 8, and a thin titanium film is formed as a base film. Then, the substrate 9 is carried into the sputtering chamber 4. Then, high-temperature reflow sputtering is performed by the above-described two-stage film formation in the sputtering chamber 4, and the film formation is completed in a state where the metal material is sufficiently buried in the holes on the surface of the substrate 9, and the holes are flattened. You. 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, and then is accommodated in the lock inside cassette 51 in the load lock chamber 5 by the transfer robot 11. Thereafter, when a predetermined number of processed substrates 9 are accommodated in the cassette 51 inside the lock, the autoloader 7 operates to carry out the processed substrates 9 to the external cassette 71.

Next, an embodiment corresponding to the sixth aspect of the present invention will be described. In the apparatus of the above-described embodiment, the number of the sputter chamber 4 is one, and the first step and the second step are continuously performed in the sputter chamber 4. However, it is possible to provide two sputtering chambers and perform the first step in one sputtering chamber and perform the second step in the other sputtering chamber. The invention according to claim 6 has this configuration. Specifically, one of the processing chambers is set as another sputter chamber (hereinafter, a second sputter chamber) in addition to the sputter chamber (hereinafter, a first sputter chamber) 4 shown in FIG. In the first sputtering chamber, the above-described distance changing mechanism 46 is unnecessary, and the substrate holder is configured such that the TS distance becomes the above-described long distance. Then, in the second sputtering chamber, the substrate holder is configured such that the TS distance is the short distance described above.

In the first sputter chamber, a heater for heating the substrate 9 is not particularly required. In the second sputter chamber, a heater similar to that in the above-described embodiment is provided. A pressurizing gas introduction system 495 is similarly provided. In this embodiment, the substrate 9 is carried into the first sputtering chamber after the pre-processing etching and the preheating are performed in the same manner. Then, after forming the base thin film in the first step in the first sputtering chamber, the substrate 9 is carried into the second sputtering chamber, and the second step is performed. That is, a thin film of a metal material is further deposited and reflowed, and the metal material is embedded in the hole. At this time, after the first step, the second step is performed continuously without taking out the substrate 9 to the atmosphere.
Therefore, there is no problem that the surface of the base thin film is oxidized or foreign matter adheres to the surface, and the fluidity of the reflow thin film is reduced in the second step, which is preferable in this respect. The advantage of this embodiment is that the tact time can be shortened because the first step and the second step are performed in different sputtering chambers. Therefore, when the processing in the sputtering chamber among the processing chambers requires the longest time in the above-described embodiment, improvement in productivity according to this embodiment can be expected. However, since the number of sputtering chambers is two, the cost of the apparatus is high. Conversely, the embodiments described above are advantageous in terms of equipment costs.

[0045]

Next, an example of the above embodiment will be described focusing on two-stage film formation. First, conditions common to the first and second steps are as follows.・ Substrate: 200mm diameter silicon wafer ・ Hole: Opening diameter 0.3μm, depth 1μm, aspect ratio 3 ・ Target: Aluminum made of 300mm diameter

The first step includes the following conditions.・ Film forming pressure: 1 mTorr ・ Discharge gas; Argon ・ Gas flow rate: 20 cc / min ・ Applied voltage to target: -500 V ・ Power applied to target; 18 kW ・ TS distance: 90 mm ・ Film forming temperature: 400 ° C. According to the method, a base thin film can be formed at a film forming speed of about 10000 angstroms per minute, and sputtering is continued for about 18 seconds to form a base thin film with a thickness of about 3000 angstroms.

The second step includes the following conditions.・ Deposition pressure: 1 mTorr ・ Discharge gas; Argon ・ Gas flow rate: 20 cc / min ・ Applied voltage to target: -300 V ・ Power applied to target: 3 kW ・ TS distance: 60 mm ・ Process temperature: 400 ° C. When the second step is performed, aluminum can be embedded in the hole in a processing time of about 120 seconds, and no void is observed.

In the embodiments and examples according to the above-described configuration and operation, the distance changing mechanism 46 is
Is moved to change the TS distance.
2 may be moved. The direction of movement is not limited to the vertical direction. When the substrate 9 and the target 42 face each other in a vertical posture, the direction of movement is horizontal. In the high-temperature reflow sputtering, the substrate 9 may be heated after the sputtering is completed to reflow the thin film. In the above-described embodiments and examples, the metal material may be embedded in the holes by performing only the heating step of the substrate 9 after the completion of the second step. In the above embodiment, the target 42 is made of aluminum. However, a copper thin film can be formed by using the copper target 42. In addition, the present invention can be similarly performed when a target made of an alloy of aluminum or copper or a target made of another metal material is used.

[0049]

As described above, according to the first aspect of the present invention, the metal material can be sufficiently buried in the holes even when the substrate is heated at a lower temperature. For this reason, it is possible to effectively embed the metal material into the holes while avoiding problems such as an increase in grain size that occur when performing high-temperature processing. According to the second aspect of the present invention, in addition to the effect of the first aspect, the first step and the second step can be performed in one sputter chamber. Lower costs. According to the third aspect of the present invention, in addition to the effect of the second aspect, since the residual impurity gas in the separation chamber is effectively removed, the quality of high-temperature reflow sputtering in the sputtering chamber can be further improved. . Further, since the removal of even the process gas is suppressed, the processing in the processing chamber does not become unstable. Further, according to the invention of claim 4, since the impurity gas entering from the load lock chamber is effectively removed, the effect of claim 3 can be further enhanced. Further, according to the invention of claim 5, since the impurity gas entering from the preheat chamber is effectively removed, the effect of claim 4 can be further enhanced. Further, according to the invention of claim 6,
In addition to the effect of the first aspect, the first step and the second step are performed in different sputtering chambers, so that the tact time can be shortened and the productivity can be increased.

[Brief description of the drawings]

FIG. 1 is a front view showing a schematic configuration of a high-temperature reflow sputtering apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic front sectional view of a sputtering chamber in the high-temperature reflow sputtering apparatus shown in FIG.

FIG. 3 is a diagram showing a problem when a film formation temperature is lowered without performing two-step film formation.

FIG. 4 is a diagram illustrating a film formation state when two-stage film formation is performed.

FIG. 5 is a schematic diagram when a TS distance is changed.

FIG. 6 is a front view showing a schematic configuration of a conventional high-temperature reflow sputtering apparatus.

[Explanation of symbols]

 Reference Signs List 1 separation chamber 11 transfer robot as transfer mechanism 2 preheat chamber 3 pretreatment etching chamber 4 sputter chamber 41 exhaust system 42 target 43 sputter power supply 44 substrate holder 441 heater 45 discharge gas introduction system 46 distance changing mechanism 48 magnet mechanism 49 electrostatic Adsorption mechanism 495 Gas supply system for pressurization 5 Load lock chamber 6 Gate valve 7 Autoloader 9 Substrate 90 Hole 91 Reflow thin film 92 Void 93 Base thin film

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 12, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

In the above-mentioned conventional high-temperature reflow sputtering, the substrate is heated from 400.degree.
It is heated to about 00 ° C. Substrate temperature during film formation (hereinafter
The lower the film formation temperature) , the higher the fluidity of the metal material,
The metal material can be easily embedded in the hole. However, by performing the treatment at such a high temperature, the crystal growth of the metal material is accelerated, and the grain size is increased. When the grain size is large, there is a problem that unevenness is formed on the surface of the substrate, and alignment in photolithography in a later step becomes difficult. Also grain
As the size increases, the problem of electromigration also becomes apparent.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

A target 42 is provided in the sputtering chamber 4 so as to expose the surface to be sputtered. The target 42 is formed of a metal material, for example, aluminum to be embedded in a hole on the surface of the substrate 9. The target 42 is attached to the sputter chamber 4 via a target holder 421 and an insulator 422 so as to hermetically close the upper opening of the sputter chamber 4. A sputtering power supply 43 for sputtering the target 42 is connected to the target 42. The sputtering power supply 43 is configured to apply a negative DC voltage of about 400 to 600 V to the target 42. When the sputtering power supply 43 is operated in a state where the gas is introduced by the discharge gas introduction system 45, a discharge is generated in the gas and the target 42 is sputtered. When sputter discharge is maintained only by ionization of sputter particles released from the target 42, gas may not be introduced in some cases.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

The dielectric block 491 is mounted on the substrate holder 4.
4 with good adhesion. The surface of the dielectric block 491 is a mounting surface on which the substrate 9 is mounted, and a plurality of recesses 494 are formed on the surface.
A pressurizing gas introduction system 495 for introducing a pressurizing gas is connected to the concave portion 494. Power supply for adsorption 493
Is configured to apply a voltage of, for example, about 200 to 800 V between the pair of adsorption electrodes 492. Dielectric polarization occurs in the dielectric block 491 by this voltage, static electricity is induced on the surface. This static electricity, the substrate 9 is electrostatically attracted to the dielectric block 491. As a result, the adhesion of the substrate 9 to the substrate holder 44 is improved, and the heat from the heater 441 is efficiently transmitted to the substrate 9. Further, as a result of the gas being introduced into the concave portion 494 by the pressurizing gas introducing system 495, the pressure in the concave portion 494 increases. For this reason, the heat transfer efficiency between the substrate holder 44 and the substrate 9 is improved, and the heating efficiency of the substrate 9 is increased. Pressurizing gas introduction system 495
Is designed to introduce a gas such as helium having a good heat transfer efficiency. The major feature of the apparatus of this embodiment is that the substrate holder 44 is provided with a distance changing mechanism 46 for changing the distance between the target 42 and the substrate 9. Specifically, the substrate holder 44 is supported by a support 442. Distance changing mechanism 46
Is a holding plate 463 holding the lower end of the support 442,
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.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

First, a case where the two-stage film formation is not performed will be described with reference to FIG. As described above, high-temperature reflow sputtering deposits a thin film on the surface of the substrate 9 in which the holes 90 are formed by sputtering.
Is heated to reflow the thin film and bury it in the hole. At this time, the reflowed thin film (hereinafter, reflow thin film) 91 tends to stay at the edge of the opening of the hole 90 due to the influence of interfacial tension and the like. In this case, as shown in FIG. 3 (A), it retained so as to reflow the thin film 91 on the edge of the opening swells. Further, a thin film is initially deposited on the inner surface of the hole 90, but as a result of the substrate 9 being exposed to a high temperature, the thin film is interrupted on the side surface of the hole 90. Then, even if the deposition amount of the thin film is increased by continuing the sputtering, only the reflow thin film 91 which rises at the edge of the opening and stays increases, and does not flow into the hole 90. As a result,
Even if the opening is closed by the reflow thin film 91 and the embedding of the metal material into the hole 90 appears to be completed, a cavity called a void is formed in the hole 90 as shown in FIG. 92 occurs. When the void 92 is formed, when a metal material is embedded as a wiring,
The wiring is broken, leading to a fatal element defect.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0022

[Correction method] Change

[Correction contents]

In order for the reflow thin film 91 to flow on the surface of the same material, a thin film of the same material may be formed on the surface in the hole 90 in advance. From such a concept, the inventor of the present application divided high-temperature reflow sputtering into two steps, and firstly, as shown in FIG. A first step of forming (hereinafter, the film formed in this step is referred to as a “base thin film”) is performed, and after the first step, FIG.
As shown in (C), a thin film of a metal material is further deposited, and the temperature of the substrate 9 is increased to cause reflow, whereby the holes 9 are formed.
Two-step film formation for performing the second step of embedding a metal material in the space
The approach was completed. In the first step, it is important to lower the film forming temperature so that the deposited base thin film 93 does not reflow. If the film formation temperature is increased to such an extent that the base thin film 93 reflows, FIG.
In the same manner as shown in FIG.
Is interrupted. If a break occurs, the reflow thin film 91 must flow over the base surface of the hole 90, so that the fluidity is reduced and voids are likely to be generated.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

A major feature of the apparatus of this embodiment is that, in the first step of the two-stage film formation, the distance between the target 42 and the substrate 9 (hereinafter, referred to as TS distance) is longer than the conventional distance. Is a point. Specifically, the control unit operates the motor 462 of the distance changing mechanism 46 to control the distance between the substrate holder 44 and the target 42 to be a long first distance in the first step, and to control the second distance. It has become one that controls the distance between the substrate holder 44 and the target 42 is shorter second distance from the first distance in the process.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction contents]

In the first step, it is preferable that the pressure in the sputtering chamber 4 during the film formation (hereinafter referred to as the film formation pressure) is lower than that of ordinary sputtering. When the pressure is high, the number of gas molecules existing in the flight space of the sputtered particles from the target 42 to the substrate 9 is large, so that most of the sputtered particles emitted from the target 42 are scattered by the gas molecules.
Although many sputtered particles can reach the surface of the substrate 9 other than the holes 90 even if they are scattered, if the scattering of sputtered particles is large, the amount of sputtered particles that can reach the inside of the hole 90 decreases. As a result, the film forming speed on the inner surface of the hole 90 is relatively reduced. Therefore, in the first step, the film forming pressure is set lower than usual so that the sputtered particles flying toward the hole 90 are not scattered. Thereby, the film forming speed on the inner surface of the hole 90 is relatively increased, and a thick base thin film 93 can be formed on the inner surface of the hole 90. Specifically, in the first step, it is preferable to set the film forming pressure to 1 mTorr or less.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction contents]

In the above-described apparatus according to the present embodiment, the substrate 9 is transferred to the processing chambers 2, 3, 4, 8 and 81 via the separation chamber 1. At this time, if there is an impurity gas in the separation chamber 1, the impurities adhere to the surface of the substrate 9. Then, there is a problem that high-temperature reflow sputtering in the sputtering chamber 4 cannot be sufficiently performed due to the attached impurities. More specifically, when water molecules adhere to the surface of the substrate 9, there is a problem in that, when the film is formed in the sputtering chamber 4, the adhesion of the thin film is impaired or the thin film is denatured such as being oxidized. is there. Further, water molecules evaporate rapidly due to the heat applied to the substrate 9 during the film formation in the sputtering chamber 4, so that irregularities are formed on the surface of the base thin film 93 by foaming or the like, or holes are formed in the base thin film 93. Sometimes. When such irregularities and holes are formed, the reflow thin film 91 does not flow well, which may cause voids.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction contents]

The panel 12 is a member made of a material having high thermal conductivity such as copper, and has a shape obtained by bending a band-like member into an arc shape as shown in FIG. As can be seen from FIG. 2, the panel 12 is in a horizontal posture, and its surface is exposed inside the separation chamber 1. In the case where the panel is made of copper, a plated nickel or the like is used to prevent corrosion of the surface. Further, as can be seen from FIG. 1, the panel 12 is located near the boundary between the two load lock chambers 5 and the preheat chamber 2.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction contents]

The cooling temperature of the panel 12 depends on each processing chip.
For processing introduced in chambers 2,3,4,8,81
Set so that even the gas (process gas) does not condense
Should. Inside each processing chamber 2, 3, 4, 8, 81
Pressure is the effective flow rate of the process gas and the exhaust system.
Panel 12 is a process gas
When these are condensed, the processing chamber
This is because the pressure becomes unstable. Also the panel
12 adsorbs not only moisture but also process gas
The amount of gas condensed on the panel 12 increases in a short time.
Therefore, the reproduction operation of the panel 12 must be performed frequently.La
And cause a decrease in productivity. Nitrogen as a process gas
Element and argon are often used and condense this
In order to avoid this, the cooling temperature of the panel 12 should be 50K or more.
Preferably. Therefore, the panel 12 is set at 130K to 5K.
The point is to control the temperature in the range of 0K.
You.

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction contents]

The fact that the surface (condensing surface) of the panel 12 is located near the load lock chamber 5 and the preheat chamber 2 is significant from the viewpoint of removing the water molecules. That is, the water molecules remaining in the separation chamber 1 enter from the atmosphere side via the load lock chamber 5 or are released from the substrate 9 at the time of preheating in the preheating chamber 2 and are separated from the preheating chamber 2 by the separation chamber. It is often the one that entered 1 Water molecules rarely enter from other chambers. Therefore, the configuration in which the surface of the panel 12 is located near the load lock chamber 5 and the preheat chamber 2 is significant in that the impurity gas is condensed only in a necessary place without increasing the surface of the panel 12 and deteriorating thermal efficiency. There is.

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction contents]

Next, the overall operation of the high-temperature reflow 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. Substrate 9 carried into cassette 51 inside lock
Is first loaded into the preheat chamber 2 by the transfer robot 11 provided in the separation chamber 1. Substrate 9 carried into preheat chamber 2
Is mounted 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. Then, the substrate 9
Is carried into a base film forming chamber 8, and a thin titanium film is formed as a base film. Then, the substrate 9 is carried into the sputtering chamber 4. Then, high-temperature reflow sputtering is performed by the above-described two-stage film formation in the sputtering chamber 4, and the film formation is completed in a state where the metal material is sufficiently buried in the holes on the surface of the substrate 9, and the holes are flattened. You. 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 as required.
Thereafter, when a predetermined number of processed substrates 9 are accommodated 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 13]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction contents]

The first step includes the following conditions.・ Film forming pressure: 1 mTorr ・ Discharge gas;
Argon gas flow rate: 20 cc / min. Applied voltage to target; -500 V. Power input to target; 18 k
W · TS distance; 90 mm · Film formation temperature; 100 to 150 ° C
According to the above conditions, a base thin film can be formed at a deposition rate of about 10000 angstroms per minute, and sputtering is continued for about 18 seconds to form a base thin film with a thickness of about 3000 angstroms.

[Procedure amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction contents]

The second step includes the following conditions.・ Film forming pressure: 1 mTorr ・ Discharge gas;
Argon gas flow rate; 20 cc / min. Applied voltage to target; -300 V; Power input to target; 3 kW
・ TS distance: 60 mm ・Film forming temperature: 400 ° C. When the second step is performed under the above conditions , aluminum can be embedded in the hole in a processing time of about 120 seconds, and no void is observed. .

[Procedure amendment 15]

[Document name to be amended] Statement

[Correction target item name] 0049

[Correction method] Change

[Correction contents]

[0049]

As described above, according to the first aspect of the present invention, the metal material can be sufficiently buried in the holes even when the substrate is heated at a lower temperature. For this reason, it is possible to effectively embed the metal material into the holes while avoiding problems such as an increase in grain size that occur when performing high-temperature processing. According to the second aspect of the present invention, in addition to the effect of the first aspect, the first step and the second step can be performed in one sputter chamber. Lower costs. According to the third aspect of the present invention, in addition to the effect of the second aspect, since the residual impurity gas in the separation chamber is effectively removed, the quality of high-temperature reflow sputtering in the sputtering chamber can be further improved. . Further, since the removal of even the process gas is suppressed, the processing in the processing chamber does not become unstable. Further, according to the invention of claim 4, since the impurity gas entering from the load lock chamber is effectively removed, the effect of claim 3 can be further enhanced. Further, according to the invention of claim 5, since the impurity gas entering from the preheat chamber is effectively removed, the effect of claim 3 or 4 can be further enhanced. Further, according to the invention of claim 6, in addition to the effect of claim 1, the first step and the second step are performed in different sputtering chambers, so that the tact time is shortened and the productivity can be increased. there is a possibility.

[Procedure amendment 16]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a high-temperature reflow spa according to an embodiment of the present invention.
FIG. 2 is a schematic plan view illustrating the configuration of the cutter device .

FIG. 2 is a schematic front sectional view of a sputtering chamber in the high-temperature reflow sputtering apparatus shown in FIG.

FIG. 3 is a diagram showing a problem when a film formation temperature is lowered without performing two-step film formation.

FIG. 4 is a diagram illustrating a film formation state when two-stage film formation is performed.

FIG. 5 is a schematic diagram when a TS distance is changed.

FIG. 6 is a front view showing a schematic configuration of a conventional high-temperature reflow sputtering apparatus.

[Procedure amendment 17]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

[Procedure amendment 18]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI H01L 21/3205 H01L 21/88 N

Claims (6)

[Claims] 1. A thin film of a metal material is formed by sputtering a metal target on the surface of a substrate on which fine holes are formed, and the substrate is heated to reflow the thin film to embed the metal material in the holes. A high-temperature reflow sputtering method, comprising: a first step of forming a base thin film of the metal material on side and bottom surfaces of the hole; and after the first step, further depositing and reflowing the thin film of the metal material. And a second step of embedding a metal material in the hole.In the first step, film formation is performed with a long first distance between the target and the substrate, and in the second step, And forming a film by setting the distance between the target and the substrate to a second distance shorter than the first distance. 2. A high-temperature reflow sputtering apparatus for forming a thin film of a metal material on a surface of a substrate having fine holes formed thereon by sputtering, heating the substrate to reflow the thin film, and embedding the metal material in the holes. A sputtering chamber provided with an exhaust system, a target provided in the sputtering chamber so as to expose a surface to be sputtered, a sputtering power source for sputtering the target, and a material of the target released by the sputtering reach A substrate holder for holding the substrate at a position to be heated, a heater for heating the substrate held by the substrate holder, a distance changing mechanism for changing the distance between the target and the substrate, and a control unit for controlling the distance changing mechanism. The control unit, the distance between the target and the substrate,
The first step of forming the base thin film of the metal material on the side and bottom surfaces of the hole has a long first distance, and after the first step, the thin film of the metal material is further deposited and reflowed to form the hole. Wherein the second step of embedding the metal material controls the distance changing mechanism so as to be a second distance shorter than the first distance. 3. A separation chamber provided at a center, a load lock chamber and a plurality of processing chambers connected airtightly around the separation chamber. A chamber in which the substrate temporarily stays when taking in and out, one of the plurality of processing chambers is the sputter chamber, and a separation chamber has a transfer for transferring the substrate between the chambers. A mechanism is provided. Further, the separation chamber has a panel provided so that the surface is exposed to the internal space of the separation chamber, and a panel is cooled to 130K to 50K to remove the impure gas in the separation chamber from the panel. A refrigerator that condenses on the surface Hot reflow sputtering apparatus according to claim 2, wherein. 4. The high-temperature reflow sputtering apparatus according to claim 3, wherein the panel is provided so that the surface is located near a boundary between the separation chamber and the load lock chamber. 5. One of the plurality of processing chambers is a preheat chamber for heating a substrate before processing in a sputter chamber, and the panel is near a boundary between the separation chamber and the preheat chamber. The high-temperature reflow sputtering apparatus according to claim 3, wherein the surface is provided at a position where the surface is located. 6. A high-temperature reflow sputtering apparatus for forming a thin film of a metal material on a surface of a substrate having fine holes formed thereon by sputtering, heating the substrate to reflow the thin film, and embedding the metal material in the holes. A separation chamber provided in the center, a load lock chamber and a plurality of processing chambers that are airtightly connected around the separation chamber, and the load lock chamber is used when a substrate is taken in and out of the atmosphere side. Is a chamber where the substrate temporarily stays, and a transfer mechanism for transferring the substrate between chambers is provided in the separation chamber, and two of the plurality of processing chambers are sputter chambers. Each of the two sputter chambers
An exhaust system for exhausting the inside, a target provided so as to expose the surface to be sputtered inside, a sputtering power supply for sputtering the target, and a substrate at a position where the target material emitted by sputtering reaches. A substrate holder for holding the substrate is provided, and the substrate holder in one of the sputtering chambers holds the substrate so that the distance between the target and the substrate becomes a long first distance, while the other The substrate holder in the chamber holds the substrate such that the distance between the target and the substrate becomes a second distance shorter than the first distance, and the other sputtering chamber holds the substrate held by the substrate holder. A high-temperature reflow sputtering apparatus having a heater for heating.