JPH0822955A - Manufacture of metal wiring layer - Google Patents

Abstract

PURPOSE:To make the formation region of a TiN film wider than a Ti film. CONSTITUTION:At the time of deposition of Ti, a semiconductor substrate 1 is fixed to a retaining stand 2 with a clamp ring 6, to which a positive bias voltage of about several tens of volt is applied. The pressure of argon gas 4 is set to 3mTorr, and a Ti target 3 is sputterd by DC power of 5kW. Thereby a Ti film 9 800Angstrom thick is deposited. In this case, the distance (T/S) between a Ti target 3 and the semiconductor substrate surface is set to 40mm. When TiN is deposited, a negative bias voltage of about several tens of volt is applied to the semiconductor substrate 1 similarly to the case of the Ti film 9. After Ar gas 4 and N2 gas 5 are mixed by the ratio of 1:1, and the pressure is set to)$& 4mTorr, the Ti target is subjected to reactive sputtering by DC power of 3kW. Thereby a TiN film 10 is deposited 1000Angstrom thick. The T/S is set to be 40mm also in this case.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a metal wiring layer using a refractory metal film which is effective for producing metal wiring used for electrically connecting a semiconductor substrate and wiring. .

[0002]

2. Description of the Related Art In recent years, as semiconductor devices have been miniaturized and integrated, the diameter of contact holes for electrically connecting a semiconductor substrate and wiring has been miniaturized. Therefore, the metal wiring layer reacts with the semiconductor substrate at the bottom of the contact hole,
There are reliability problems such as an increase in leakage current and an increase in contact resistance. Therefore, a two-layer film of a titanium (Ti) film and a titanium nitride (TiN) film is formed as a shielding film (hereinafter referred to as a barrier metal) between the wiring film and the semiconductor substrate to prevent the reaction.

A conventional method for producing Ti and TiN will be described below with reference to FIG. FIG. 5A shows a method of depositing a Ti film and a TiN film by a sputtering method, and shows a state of a semiconductor substrate in a sputtering film forming apparatus. Further, FIG. 5B is an enlarged view of the semiconductor substrate fixing portion in FIG. 5A.

First, at the time of depositing Ti, the outer peripheral portion of the semiconductor substrate 1 is preliminarily formed into a ring-shaped jig (hereinafter referred to as a clamp ring 6).
Fixed) to the support base. And argon (A
r) Sputter with gas 4 to deposit Ti film 9.
Next, when depositing the TiN film 10, the semiconductor substrate 1 is fixed, the Ar gas 4 and the nitrogen (N ₂ ) gas 5 are mixed and reactive sputtering is performed as in the case of the Ti film 9.
The iN film 10 is deposited. The deposition of the Ti film 9 and the TiN film 10 is continuously performed while the semiconductor substrate 1 is being held by the same clamp ring 6.

The fixed portion of the semiconductor substrate 1 is shown enlarged in FIG. In the vicinity of the fixed portion of the semiconductor substrate 1, the Ti film 9 has a T
Deposit from the iN film 10 to the outer peripheral portion of the semiconductor substrate 1. Therefore, the Ti film 9 is exposed on the outer peripheral portion of the semiconductor substrate 1.

After the Ti film 9 and the TiN film 10 are deposited as described above, a wiring layer such as a tungsten (W) film or an aluminum (Al) alloy film is formed thereon. However, at this time, the following problems occur. This will be described with reference to FIG.

FIG. 6 shows tungsten (W) formed by the CVD method.
3 shows a procedure of a process for filling a contact hole of a film. First, FIG. 6A shows the Ti film 9 by the method described in FIG.
The process of depositing the TiN film 10 inside and outside the contact hole is shown. Next, FIG. 6B shows a step of depositing the W film 18 inside and outside the contact hole by the CVD method. The W film is deposited by reducing tungsten hexafluoride (WF ₆ ) to W with hydrogen (H ₂ ) or silane (SiH ₄ ). Next, in FIG. 6 (c), W is formed only in the contact hole.
The whole surface etching process for leaving the film 19 is shown.
At this time, etching is performed until the W film 18 and the TiN film 10 and the Ti film 9 as the underlying film are removed outside the contact hole. Finally, as shown in FIG.
A wiring layer is formed by a three-layer film including the iN film 20-Al alloy film 21-TiN film 22.

[0008]

The W film 18 shown in FIG. 6B is used.
During the growth, WF ₆ gas is used as TiN in the outer peripheral portion of the semiconductor substrate 1.
It does not contact the film 10 but contacts the Ti film 9. WF gas is Ti
Although it has low reactivity with the N film 10, it has very high reactivity with the Ti film 1. Therefore, the Ti film 9 peels off at the outer peripheral portion of the semiconductor substrate 1 due to the reaction between the Ti film 9 and the WF6 gas. As a result, there is a problem in that foreign substances are generated from the outer peripheral portion of the semiconductor substrate 1 and a yield in manufacturing a semiconductor device is reduced.

[0009] The present invention is intended to solve the conventional problems described above, on a semiconductor substrate, a Ti film and WF ₆ when the W film is deposited by depositing a TiN film to a more peripheral portion of the semiconductor substrate than the Ti film It is possible to prevent the reaction with.
Therefore, a method for manufacturing a metal wiring layer having a high yield is provided.

[0010]

In order to solve the above-mentioned problems, a method for manufacturing a metal wiring layer of the present invention is to continuously press a titanium film and a titanium nitride film by pressing an outer peripheral portion of a semiconductor substrate with a ring-shaped jig. During the deposition, a titanium bias film is deposited by applying a positive bias voltage to the jig during sputtering, and a titanium film is deposited, and a titanium nitride film is deposited by applying a negative bias voltage to the jig. And the process.

In addition, when the titanium film and the titanium nitride film are continuously deposited by pressing the outer peripheral portion of the semiconductor substrate with a ring-shaped jig, the semiconductor substrate and the titanium film are deposited more when the titanium nitride film is deposited than when the titanium film is deposited. When the titanium nitride film is deposited, the forming pressure is made smaller than that at the time of depositing the titanium film, or in the mixed gas when the titanium nitride film is formed, nitrogen (N) is used instead of argon (Ar) gas. ₂ ) Increase the partial pressure of gas.

The step of depositing a titanium film by pressing the outer peripheral portion of the semiconductor substrate with a ring-shaped jig and the step of depositing a titanium nitride film with a gap between the jig and the semiconductor substrate are consecutive. Then do.

When the titanium film and the titanium nitride film are deposited by pressing the outer peripheral portion of the semiconductor substrate with a ring-shaped jig, a positive bias voltage of several tens of volts is applied to the back surface of the semiconductor substrate during the deposition of the titanium film to nitride the titanium film and the titanium nitride film. A negative bias voltage of several tens of volts is applied to the back surface of the semiconductor substrate when depositing the titanium film.

Further, when a titanium film and a titanium nitride film are continuously deposited while the outer peripheral portion of the semiconductor substrate is being held by a ring-shaped jig, the surface temperature of the semiconductor substrate is set to 100 ° C. or lower when the titanium film is deposited. During the deposition of the titanium nitride film, the surface temperature of the semiconductor substrate is set to 400 ° C. or lower.

[0015]

According to the present invention, Ti is formed on the semiconductor substrate.
Since it becomes possible to deposit N from Ti to the outer peripheral portion of the semiconductor substrate, Ti and S when removing W by etching
The reaction with F ₆ can be prevented and the generation of foreign matter can be eliminated.

[0016]

Embodiments of the method of manufacturing a semiconductor device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of one embodiment of the method of manufacturing a semiconductor device of the present invention. In FIG. 1, 1 is a semiconductor substrate, 2 is a support, 3 is a Ti target, 4 is Ar gas,
5 is N ₂ gas, 6 is a clamp ring, 7 is a shield plate, 8 is a DC power supply, 9 is Ti, 10 is TiN, 11 is a positive DC bias power supply for applying a DC voltage to the clamp ring 6, and 12 is Similarly, a negative DC bias power source, 13 is an eave at the end of the clamp ring, 14 is an insulating film on the semiconductor substrate, and 15 is the distance between the Ti target and the semiconductor substrate surface (hereinafter T / S).
It means that).

FIG. 1 (a) shows T obtained by the sputtering method.
1 shows a method of depositing i and TiN, showing a state of a semiconductor substrate in a sputtering film forming apparatus. Further, FIG. 1B is an enlarged view of the semiconductor substrate fixing portion in FIG.

First, when depositing Ti, the semiconductor substrate 1 is previously fixed to the support base 2 by the clamp ring 6, and a positive bias voltage of about several tens of V is applied to the clamp ring 6. Then, the pressure of the Ar gas 4 is set to 3 mTorr, and the Ti target 3 is sputtered by DC power of 5 kW to deposit a Ti film 9 of 800 Å. At this time, the Ti target 3 and (T / S) are set to 40 mm. Then T
At the time of depositing iN, the semiconductor substrate 1 is fixed similarly to the case of the Ti film 9, and a negative bias voltage of about several tens V is applied to the clamp ring 6 in advance. And Ar gas 4
And N ₂ gas 5 were mixed at a ratio of 1: 1 and the pressure was 4 mTo.
After setting to rr, a Ti target 10 is reactively sputtered with a DC power of 3 kW to deposit a TiN film 10 of 1000 Å. Also at this time, T / S is set to 40 mm. When the Ti film 9 and the TiN film 10 are deposited, the surface of the semiconductor substrate 1 is covered with an insulating film, so that the clamp ring 6 and the semiconductor substrate 1 are electrically insulated. Therefore, the positive and negative bias voltages applied to the clamp ring 6 are not applied to the semiconductor substrate 1.

When the Ti is deposited, the clamp ring 6 has a positive bar.
By applying the bias voltage, Ar ⁺Ion clamp
Since it is kept away from ring 6, a positive bias voltage is applied.
As compared with the case where Ti is not added, Ti is deposited on the outer peripheral portion of the semiconductor substrate 1.
It becomes difficult to stack. On the clamp ring 6 when depositing TiN
By applying a negative bias voltage, Ar⁺AEON
Positive bias voltage because it is attracted to the ramp ring
As compared with the case where no voltage is applied
Are easily deposited. Furthermore, Ar⁺Ion clamp
It will be pulled onto the ring and
Since the deposited TiN is re-sputtered,
The peripheral portion makes it easier to deposit.

A second embodiment of the semiconductor device manufacturing method of the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view of an embodiment of the method for manufacturing a semiconductor device of the present invention. In FIG. 2, 1 is a semiconductor substrate, 2 is a support, 4 is Ar gas, 5 is N ₂ gas, 6 is a clamp ring, 7 is a shield plate, 8 is a DC power supply, 9 is Ti,
10 is TiN, 13 is an eave at the end of the clamp ring, and 15 is T
Distance between i target and semiconductor substrate surface (T / S)
Is shown.

FIG. 2A shows Ti formed by the sputtering method.
2 shows the state of the semiconductor substrate in the sputtering film forming apparatus. 2 (b) is shown in FIG.
Similar to (a), it shows a TiN deposition method. FIG. 2C is an enlarged view of the semiconductor substrate fixing portion in FIGS. 2A and 2B.

First, when depositing Ti, the first embodiment 1
Similarly, the semiconductor substrate 1 is previously fixed to the support base 2 by the clamp ring 6. Then, the pressure of Ar gas 4 is set to 1 m.
The Ti target is sputtered with a DC power of 5 kW, and the Ti film 9 is deposited to 800 Å. At this time, T / S is set as large as 100 mm or more. Next, when depositing TiN, the semiconductor substrate 1 is fixed as in the case of the Ti film 9. And Ar gas 4
And N ₂ gas 5 were mixed at a ratio of 1:10 and the pressure was 5 m.
After setting a large value of Torr, Ti with 3kW DC power
By reactively sputtering the target, Ti
The N film 10 is deposited at 1000 Å. At this time T / S is 30
Set it to be less than mm.

When T / S is set to 100 mm or more at the time of depositing Ti, Ti sputtered from the Ti target has a strong tendency to go straight. Therefore, compared with the case where T / S is set to 40 mm, clamping is performed. It becomes difficult for Ti to enter under the eaves 13 of the ring 6. When TiN is deposited, it becomes difficult for T / S to deposit Ti on the outer peripheral portion of the semiconductor substrate. By setting T / S to 30 mm or less when depositing TiN, the T sputtered from the Ti target 3 is
iN has a weak straight-line progression, so T / S is 40 m
As compared with the case where m is set, TiN is more likely to wrap around the eaves 13 of the clamp ring 6. Furthermore, since Ti has a strong ability to travel straight ahead, Ti is likely to be deposited on the bottom of the fine contact hole. Therefore, the coverage of Ti on the bottom of the contact hole is improved, and the contact resistance is reduced.

A third embodiment of the semiconductor device manufacturing method of the present invention will be described below with reference to the drawings.

FIG. 3 is a sectional view of an embodiment of the method of manufacturing a semiconductor device of the present invention. In the figure, 1 is a semiconductor substrate, 2 is a support, 6 is a clamp ring, 9 is Ti, and 10
Indicates TiN, and 13 indicates the eaves at the end of the clamp ring.

FIG. 3A shows Ti formed by the sputtering method.
Fig. 3 is an enlarged view of the fixed part of the semiconductor substrate during the deposition of
(B) It is an enlarged view at the time of depositing TiN.

First, when depositing Ti, the semiconductor substrate 1 is previously fixed to the support base 2 by the clamp ring 6. Then, the pressure of the Ar gas 4 is set to 3 mTorr and 5 k
Sputtering a Ti target with DC power of W
The i film 9 is deposited at 800 Å. At this time, T / S is 40 mm
Set to. Next, at the time of depositing TiN, the clamp ring 6 that fixed the semiconductor substrate 1 was removed from the semiconductor substrate 1 by 5 m.
m away. Then, Ar gas 4 and N ₂ gas 5 were mixed at a ratio of 1: 1 and the pressure was set to 4 mTorr, and then 3 k
The TiN film 10 is deposited by 1000 Å by reactively sputtering a Ti target with a DC power of W. At this time, T / S is set to 40 mm.

By separating the clamp ring 6 from the semiconductor substrate 1 at the time of depositing TiN, TiN sputtered from the Ti target 3 can easily go under the eaves 13 of the clamp ring 6. Further, the distance between the clamp ring 6 and the semiconductor substrate 1 is increased so that the TiN and the semiconductor substrate 1 are
The effect of suppressing the generation of foreign matter due to the adhesion of the is doubled.

A fourth embodiment of the semiconductor device manufacturing method of the present invention will be described below with reference to the drawings.

FIG. 4 is a sectional view of an embodiment of the method of manufacturing a semiconductor device of the present invention. In the figure, 1 is a semiconductor substrate, 2 is a support base, 3 is a Ti target, 4 is Ar gas,
5 is N ₂ gas, 6 is a clamp ring, 7 is a shield plate, 8 is a DC power source, 9 is Ti, 10 is TiN, 13 is an eave at the end of the clamp ring, and 15 is the distance between the Ti target and the surface of the semiconductor substrate (hereinafter T / S), 16 indicates a bias power source applied to the semiconductor substrate.

FIG. 4 (a) shows T obtained by the sputtering method.
1 shows a method of depositing i and TiN, showing a state of a semiconductor substrate in a sputtering film forming apparatus. FIG. 4
FIG. 4B is an enlarged view of the semiconductor substrate fixing portion shown in FIG.

First, when depositing Ti, the semiconductor substrate 1 is previously fixed to the support base 2 by the clamp ring 6, and a positive bias voltage of about several tens of volts is applied to the semiconductor substrate 1 from the back surface. Then, the pressure of the Ar gas 4 is set to 3 mTorr, and a Ti target is sputtered with a DC power of 5 kW to deposit a Ti film 9 of 800 Å. At this time T /
S is set to 40 mm. Next, when TiN is deposited, T
Similarly to the case of the i film 9, the semiconductor substrate 1 is fixed, and a negative bias voltage of about several tens of V is applied to the semiconductor substrate 1 from the back surface. Then, Ar gas 4 and N ₂ gas 5 are mixed at a ratio of 1: 1 and the pressure is set to 4 mTorr, and then TiN is deposited by 1000 Å by reactively sputtering a Ti target with a DC power of 3 kW. Also at this time, T / S is set to 40 mm. At the time of depositing Ti and TiN, the surface of the semiconductor substrate 1 is covered with an insulating film, so that the clamp ring 6 and the semiconductor substrate 1 are electrically insulated. Therefore, the positive and negative bias voltages applied to the semiconductor substrate 1 are not applied to the clamp ring 6.

By applying a positive bias voltage from the back surface of the semiconductor substrate 1 at the time of depositing Ti, Ar ⁺ ions are moved away from the surface of the semiconductor substrate 1, so that the clamp ring 6 is different from the case where no positive bias voltage is applied. It becomes difficult for Ti to get under the eaves 13 of the above. By applying a negative bias voltage from the back surface of the semiconductor substrate 1 at the time of depositing TiN, Ar ⁺ ions are attracted to the front surface of the semiconductor substrate 1, so that the eaves 13 of the clamp ring 6 are different from the case where no positive bias voltage is applied. TiN easily wraps around underneath. Further, since Ar ⁺ is attracted to the semiconductor substrate 1 during the deposition of TiN, the T deposited once on the semiconductor substrate 1
Since a phenomenon in which the iN film is re-sputtered and redeposited occurs, TiN is activated and the crystal orientation becomes very good.

A fifth embodiment of the semiconductor device manufacturing method of the present invention will be described below with reference to the drawings. The drawing uses that of the fourth embodiment.

First, at the time of depositing Ti, the semiconductor substrate 1 is previously fixed to the support base 2 by the clamp ring 6, the semiconductor substrate 1 is cooled from the back surface, and the surface temperature of the semiconductor substrate 1 is set to 2 ° C.
Keep at 0 ° C to 25 ° C. Then, the pressure of the Ar gas 4 is set to 3
Setting to mTorr, a Ti target is sputtered with a DC power of 5 kW to deposit a Ti film 9 of 800 Å.
At this time, T / S is set to 40 mm. Next, when depositing TiN, the semiconductor substrate 1 is fixed as in the case of the Ti film 9, the semiconductor substrate 1 is heated from the back surface, and the surface temperature of the semiconductor substrate 1 is maintained at 450 ° C. Then, Ar gas 4 and N ₂ gas 5 were mixed at a ratio of 1: 1 and the pressure was set to 4 mTorr. Then, the Ti target was reactively sputtered with a DC power of 3 kW to form a TiN film 10 of 1000 Å.
accumulate. Also at this time, T / S is set to 40 mm.

As described above, according to the present invention, Ti
It was possible to deposit N from Ti to the outer peripheral portion of the semiconductor substrate.

By cooling the semiconductor substrate 1 from the back surface during the deposition of Ti, when Ti sputtered from the Ti target 3 reaches the surface of the semiconductor substrate 1, heat energy is not applied and the Ti migration on the surface. Is reduced. Therefore, it is possible to prevent the clamp ring 6 from wrapping under the eaves 13 due to the migration of the substrate surface. By heating the semiconductor substrate 1 from the back surface at the time of depositing TiN, when TiN sputtered from the target reaches the front surface of the semiconductor substrate, thermal energy is given and the migration of Ti on the surface is improved. Therefore, it is possible to improve the wraparound of the clamp ring 6 below the eaves 13 due to the migration of the substrate surface.

[0040]

According to the present invention, when the aluminum alloy film is buried, the refractory metal film of the underlying layer has a three-layer structure of Ti, TiN, and Ti film so that the temperature at which the aluminum alloy film is buried is 650. It was possible to lower the temperature from ℃ to 550 ℃. Furthermore, when depositing three refractory metal films of Ti, TiN, and Ti films, the semiconductor substrate temperature is set to 4
When deposited at 50 ° C., the temperature at which the aluminum alloy film was embedded could be lowered from 550 ° C. to 480 ° C. Therefore, the aluminum alloy layer can be deposited at a lower temperature, and the yield and reliability of the wiring can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory view of a first embodiment of a method for manufacturing a metal wiring layer according to the present invention.

FIG. 2 is an explanatory view of a second embodiment of the method for manufacturing a metal wiring layer according to the present invention.

FIG. 3 is an explanatory view of a third embodiment of the method for manufacturing a metal wiring layer according to the present invention.

FIG. 4 is a fourth method of manufacturing a metal wiring layer according to the present invention;
Explanatory drawing of the fifth embodiment

FIG. 5 is an explanatory view of a conventional method for manufacturing a metal wiring layer.

FIG. 6 is an explanatory view of a conventional contact hole filling method.

[Explanation of symbols]

1 semiconductor substrate 2 support 3 Ti target 4 Ar gas 5 N ₂ gas 6 clamp ring 7 shielding plate 8 DC power supply 9 Ti 10 TiN 11, 12 DC bias power supply 13 eaves 14 insulating film 15 distance 16 bias power supply 17 interlayer insulating film 18 , 19 W film 20 TiN film 21 Al alloy film 22 TiN film

Claims (5)

[Claims] 1. When a titanium film and a titanium nitride film are successively deposited by pressing an outer peripheral portion of a semiconductor substrate with a ring-shaped jig, a positive bias voltage is applied to the jig when the titanium film is deposited and sputtering is performed. And then depositing a titanium film, and performing a sputtering by applying a negative bias voltage to the jig to deposit a titanium nitride film. 2. When the titanium film and the titanium nitride film are successively deposited by pressing the outer peripheral portion of the semiconductor substrate with a ring-shaped jig, the semiconductor film is deposited more when the titanium nitride film is deposited than when the titanium film is deposited. The distance between the substrate and the titanium target is increased, and the forming pressure at the time of depositing the titanium nitride film is made smaller than that at the time of depositing the titanium film, or in the mixed gas for forming the titanium nitride film, argon (Ar) is used. ) A method for producing a metal wiring layer, wherein the partial pressure of nitrogen (N ₂ ) gas is higher than that of gas. 3. A step of depositing a titanium film by pressing an outer peripheral portion of a semiconductor substrate with a ring-shaped jig, and a step of depositing a titanium nitride film with a gap provided between the jig and the semiconductor substrate. A method for manufacturing a metal wiring layer, which is characterized in that it is carried out continuously. 4. A positive bias voltage of several tens of volts is applied to the back surface of the semiconductor substrate when the titanium film and the titanium nitride film are deposited by pressing the outer peripheral portion of the semiconductor substrate with a ring-shaped jig. A method for manufacturing a metal wiring layer, wherein a negative bias voltage of several tens of V is applied to the back surface of the semiconductor substrate during the deposition of the titanium nitride film. 5. The surface temperature of the semiconductor substrate is set to 100 ° C. or lower when the titanium film and the titanium nitride film are continuously deposited while holding the outer peripheral portion of the semiconductor substrate with a ring-shaped jig. A method of manufacturing a metal wiring layer, wherein the surface temperature of the semiconductor substrate is set to 400 ° C. or lower during the deposition of the titanium nitride film.