JPH04187793A - Semiconductor device and its production - Google Patents

Abstract

PURPOSE:To produce a semiconductor device with its opening being always covered by impressing the voltage/current alternately changing its direction between a plating electrode in a plating soln. and an electrode connected to a conductive material to be plated. CONSTITUTION:A plating tank 24 is filled with a plating soln. 25 contg. a surface brightener as the additive. One plating electrode 26a and a conductive material 27 to be plated connected to the other plating electrode 26b are dipped in the soln. 25. The electrode 26a is connected to minus of a DC power source 28 and to plus of a pulse power source 29, and the electrode 26b to plus of the source 28 and to minus of the source 29. Both power sources 28 and 29 are superimposed, and the voltage/current alternately changing its direction is impressed on the electrodes 26a and 26b. The additive forms a nucleus, a conductive plating film is formed on the material 27 with the opening being always covered and then removed by the counter voltage/current, hence the electric resistance of the conductive film is reduced, and an increase in hardness is prevented.

Description

[Detailed Description of the Invention] [Table of Contents] - Overview - Field of industrial application - Conventional technology (Figures 5 to 7) - Problems to be solved by the invention - Means and effects for solving the problems - Examples ■First example (Fig. 1, Fig. 2) ■Second example (Fig. 3) ■Third example (Fig. 4) - Effects of the invention [Summary] Semiconductor device and its Regarding the manufacturing method, more specifically, regarding a semiconductor device having an electrode, etc. formed by covering a contact hole or a peer hole by electrolytic plating, and its manufacturing method, the coverage of the opening is maintained, and the electrical conductivity of the electrode or wiring is maintained. The purpose of the present invention is to provide a semiconductor device and a method for manufacturing the same that can reduce resistance and further reduce strain that occurs in an insulating film due to the hardness of electrodes or wiring metal. , one plating electrode and a conductive object to be plated connected to the other plating electrode are placed in a plating solution containing additives, and a voltage/current with alternating directions is applied between the plating electrodes. The semiconductor device includes forming a conductive film on a plated conductor, and firstly, a conductive film is formed by electrolytic plating on a conductive film to be plated that covers an opening in an insulating film on the conductor. A semiconductor device having a multilayer conductive film having more than one layer,
The first conductive film at the bottom layer of the multilayer conductive film is formed using a plating solution containing no additives, and the first conductive film is formed using a plating solution containing no additives.
The second conductive film on the conductive film is formed using a plating solution containing an additive, and secondly,
The second conductive film formed using the plating solution containing the additive is formed by the manufacturing method according to the first invention.

[Industrial application field]

The present invention relates to a semiconductor device and a method for manufacturing the same, and more specifically, to a semiconductor device having electrodes formed by covering contact holes and peer holes by electrolytic plating, and a method for manufacturing the same.

In recent years, as semiconductor devices have become more densely packed, wiring has become more multilayered and finer, and the surface of semiconductor substrates has become increasingly uneven. Therefore, since the aspect ratio of pier holes and the like becomes large, a method of forming wiring and the like with good coverage is desired.

(Prior Art) Conventionally, as a method for forming wiring and the like with good coverage, there is an electrolytic plating method using a plating solution containing a surface brightener.

FIGS. 7(a) to 7(c) are cross-sectional views illustrating a method of forming an upper wiring layer and a lower wiring layer using such an electrolytic plating method.

First, the contact hole 2a formed in the base insulating film 2 on the semiconductor substrate Fi1 and the buffer electrode 3 shown in No. 7e(a) is covered with a first base conductive film 4 by sputtering or the like.
After forming the first base conductor 1, electrolytic plating is performed using a plating solution 1o containing a surface brightener in a plating bath 9 shown in FIG. 5 and applying voltage/current from a DC IF source 13. A first Au film 5 is formed on the film 4 (the conductive material 12 to be plated). At this time, the first Au film 5 with good coverage is applied to the action of the surface brightener that smooths out the unevenness of the surface.
is formed (Fig. 7(b)).

Next, the first Au film (lower conductive film) 5 and the first base conductive film 4 are patterned to form a lower wiring layer 12a, and then an interlayer insulating film 6 is formed to cover the lower wiring layer 12a.

Next, after forming a pier hole 6a in the interlayer insulating film 6 on the lower wiring layer 12a, the pier hole 6a is covered with a second Au film (upper conductor 1) in the same manner as shown in FIG. 7(b).
After that, the second Au film 8 and the second underlying conductive film 7 are patterned to form an upper wiring layer 12b (FIG. 7(C)).

[Problem to be solved by the invention]

However, in the above method, the formed first and second A
■Hard because the u-films 5 and 8 contain a surface brightener.

■High electrical resistance.

Therefore, (1) it comes into contact with the first and second Au films 5 and 8; Alternatively, stress may be applied to the adjacent base insulating film 2 or interlayer insulating film 6, causing cracks to appear in these insulations M2 and 6, resulting in a decrease in insulation properties.

■The voltage drop is large and the characteristics of the semiconductor device are degraded.

There is a problem.

The present invention has been made in view of such conventional problems, and it maintains the coverage of the opening, reduces the electrical resistance of the electrode or wiring, and further improves the resistance of the insulating film due to the hardness of the electrode or wiring metal. It is an object of the present invention to provide a semiconductor device and a method for manufacturing the same that can reduce distortion caused in the semiconductor device.

[Means to solve the problem]

First, one plating electrode and a conductive material to be plated connected to the other plating electrode are placed in a plating solution containing additives, and a voltage/current that alternately changes direction is applied to the plating electrode. This is achieved by a method for manufacturing a semiconductor device characterized in that a conductive film is formed on the conductive material to be plated by applying an electric current between the conductive material and the conductive material to be plated. A semiconductor device having a multilayer conductive film of two or more layers formed by electrolytic plating on a film,
The first conductive film at the bottom layer of the multilayer conductive film is formed using a plating solution containing no additives, and the first conductive film is formed using a plating solution containing no additives.
A semiconductor device characterized in that the second conductive film on the conductive film is formed using a plating solution containing an additive, and thirdly, an opening in the insulating film on the conductor. A semiconductor device having a multilayer conductive film of three or more layers formed by electrolytic plating on a conductive film to be plated that covers a conductive film, the first conductive film being the bottom layer and the third conductive film being the top layer of the multilayer conductive film. The conductive film does not contain additives.

A semiconductor device, characterized in that the semiconductor device is formed using a plating solution, and the semiconductor device is formed using a plating solution that contains an additive between the first conductive film and the third conductive film. Fourthly, the second conductive film formed using the plating solution containing the additive is formed by the method according to the first invention. invention or third
This is achieved by the semiconductor device according to any one of the inventions.

[Operation] According to the method for manufacturing a semiconductor device of the first invention, the method shown in FIG.
As shown in a), (b) and Fig. 2 (a), (b),
Since the voltage/current for plating is applied in alternating directions, first the plating electrodes 26a and 2 in FIG.
While the current is flowing from 6b toward the conductive material 27 to be plated (Fig. 2(c) and (d)), the surface brightener (additive)
33 is electrodeposited on the convex portion 35 of the conductive material 27 to be plated, and the conductive film 34 is electrodeposited using this as a nucleus (however, while flowing in the opposite direction (Fig. 2(e)), the conductive film 34 is electrodeposited on the convex portion 35 of the conductive material 27 to be plated. The surface brightener 33 electrodeposited from the object 27 is removed. Therefore, the content of the surface brightener 33 in the conductive film 34 formed by repeating this process (FIG. 2(f) to (i)) is Decrease sharply.

Thereby, electrical resistance can be reduced.

Moreover, since electrodeposition is performed via the surface brightener 33,
Due to the action of the surface brightener 33, the coverage of the conductive film 34 is maintained as it was.

Further, according to the semiconductor device of the second invention, a surface brightener (
A first conductive film created using a plating solution containing no additives is provided closer to the insulating film.

Furthermore, when covered with an interlayer insulating film, the first conductive film at the bottom layer and the third conductive film at the top layer contain a surface brightener (additive) as in the semiconductor device of the third invention. If the first conductive film and the third conductive film are formed using a plating solution other than the interlayer insulating film, the first conductive film and the third conductive film will be close to or in contact with the interlayer insulating film.

Therefore, since the conductive film created using a plating solution that does not contain a surface brightener is usually soft, a plating solution that does not contain a surface brightener is used between the first and third conductive films. Even if the hard second conductive film is present, the stress from the second conductive film to the insulating film is alleviated by the first and third conductive films. In particular, the electrical resistance can be reduced by forming the second conductive film by the electrolytic plating method described in the first invention.

Furthermore, if only the first or third conductive film is formed using a plating solution that does not contain a surface brightener, the coverage will be deteriorated. A second conductive film made using a plating solution that does not contain a surface brightener is formed between the conductive film and the second conductive film, thereby maintaining the original coverage.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

■First Example The electrolytic plating method of the first example of the present invention is shown in Figure 1 (
This will be explained with reference to a), (b) and FIGS. 2(a) to (i).

FIG. 1 is a diagram for explaining the electrolytic plating method according to the first embodiment of the present invention, and FIGS. 2(a) to (i) are diagrams for explaining the operation.

First, as shown in FIG. 1(a), as a metal plating liquid 24 containing a surface brightener (additive), for example, the Au plating liquid AUTOTROL manufactured by Nikki Koutro Plating Enjurs Co., Ltd. (EEJA) is used. Place NEX MP (trade name) into the plating tank 24. One of the plated electrodes 26a is a mesh-like plated electrode made of titanium (Ti) coated with a platinum (Pt) film.
and the conductive material to be plated 27 connected to the other plating electrode 26b. Furthermore, these electrodes 26a, 26
An example of a DC power supply 28 and the + side thereof are connected to b, respectively, and the + side of a pulse power supply 29 is connected in parallel with the DC power supply 28.

Connect the − side.

Next, as shown in FIG. 1(b), the DC power supply 28 supplies a DC current with a current density (Jl) of about 1 mA/cm'', and the pulse power supply 29 supplies a DC current with a current density (Jl) of about 100 mA/cm''. ~50 (l m A / cm'.

When a pulse current with a pulse width of 0.1 seconds and 3 cycles of 1 second is supplied, an Au film (conductive film) begins to be electrodeposited on the conductive material 27 to be plated.

At this time, the voltage/current for plating is applied while changing the direction alternately, so first, while the current is flowing from the plating electrode 26a toward the conductive object 27 to be plated (second
Figures (c) and (d) show that the surface brightener 33 is electrodeposited on the convex portion 35 of the conductive material 27 to be plated, and uses this as a core to form the conductive film (second
The electroconductive film 34 is electrodeposited, but while the electroconductive film 34 is flowing in the opposite direction (FIG. 2(e)), the electrodeposited surface brightener 33 is removed from the conductive material 27 to be plated. Therefore, the conductive film 34 formed by repeating this process (FIG. 2(f) to (i))
The content of the surface brightener 33 inside is drastically reduced.

Thereafter, by maintaining this state for a predetermined time, a conductive film 34 having a predetermined thickness is electrodeposited.

As described above, according to the electrolytic plating method of the first embodiment,
Since the content of the surface brightener 33 in the formed conductive film 34 is drastically reduced, the hardness and electrical resistance can be reduced. Moreover, since the electrodeposition is performed via the surface brightener 33, the conductive film 3 is electrodeposited by the action of the surface brightener 33.
The coverage of 4 is kept intact.

Note that in the first embodiment, an Au plating solution is used, but aluminum (Af) and copper (Cu) are used.

Plating solutions of nickel (N i ), platinum (Pt), Rh, and Ru can be used.

■Semiconductor device according to the second embodiment Next, we will discuss the semiconductor device according to the second embodiment of the present invention in the third section.
This will be explained with reference to the figures.

FIG. 3 is a sectional view of a semiconductor device according to a second embodiment of the present invention.

In the figure, 14 is a semiconductor substrate made of a compound semiconductor or the like, 16 is a buffer electrode selectively provided on the semiconductor substrate I4 to connect the semiconductor substrate 14 to wiring, and 1
5 is a Si provided to expose the buffer electrode 16.
A base insulating film WI (insulating film) 15a made of an O□ film or the like is a contact hole (opening) provided in the base insulating film 15 on the buffer electrode 16.

In addition, 17 is a film thickness of approximately 30 mm for electrodepositing plating metal.
The base conductive film 18a consists of a Ti film of 0.0000000000000000 and a sieve film of about 1000000000000 on top of it. The film thickness on the base conductive film 17 created by
The first conductive film 18a is made of 0% Au and is soft because it does not contain a surface brightener. Furthermore, 1
9 is the first step using a plating solution containing a surface brightener (additive).
The second conductive film 19 is made of Au with a thickness of 5000 to 6000 on the first conductive film 18a prepared by the electrolytic method of Example 1. Since the amount is very small, the film is softer and has a much lower electrical resistance than a film that normally contains a surface brightener. Although the amount of the surface brightener is very small, since it contains the surface brightener, it is harder than the first conductive film 18a that contains the surface brightener. A soft third conductive film made of Au with a film thickness of 2,000 to 4,000 nm is formed on the second conductive film 19, which is created by a normal DC electrolytic plating method using a plating solution that does not contain a surface brightener in the same manner as above. be. Note that the first conductive film 1
A multilayer conductive film 31 is composed of three layers of 8a/second conductive film 19/third conductive film 18b, and this multilayer conductive film 31 and base conductive film 17 constitute a lower wiring layer.

Furthermore, 20 is PS with a thickness of about 1 μm covering the lower wiring layer.
An interlayer insulating film made of a G film or the like, 20a a peer hole (opening) provided on the lower wiring layer, 21 made of the same metal as the base conductive film 17 constituting the lower wiring layer, and formed by the same method. An underlying conductive film consisting of a Ti film with a thickness of about 300 thick covering the peer hole 20 and a U film overlying it with a thickness of about 1000 thick, 22 is the same plating solution as the first conductive film 18a constituting the lower wiring layer. , and formed in a similar manner,
A first conductive film 23 made of soft Au having a film thickness of 2,000 to 4,000 on the base conductive film 21 is formed using the same plating solution and using the same method as the second conductive film 19 constituting the lower wiring layer. In addition, the film thickness on the first conductive film 22 is 50 OO~
This is a second conductive film made of slightly harder Au of 6,000 yen. Note that these first conductive films 22/second conductive films 23
The two-layer film is multilayer conductive W! 32, and this multilayer conductive film 32 and base conductive film 21 constitute an upper wiring layer.

According to the semiconductor device of the second embodiment as described above, in the lower wiring layer, the first conductive film 18a and the third conductive film 18b are formed using a plating solution that does not contain a surface brightener. A second conductive film created using a plating solution containing a brightener is sandwiched therebetween.

Therefore, the soft first conductive film 18a and the third conductive film 1
8b is close to or in contact with the insulating film 15.20, even if the harder second conductive film 11119 exists between the first conductive film 18a and the third conductive film 18b, the first The stress from the second conductive film 19 to the insulating film is relaxed by the conductive film 18a and the third conductive film 18b. Furthermore, since the second conductive film 19 contains only a small amount of surface brightener,
Electrical resistance can be reduced.

In addition, since the upper wiring layer also has the soft first conductive film 22 between the interlayer insulating film 20 and the hard second conductive film 23, it has the same function and effect as the lower wiring layer. . Furthermore, since the second conductive film 23 contains only a small amount of surface brightener, electrical resistance can be reduced.

In addition, in the second embodiment, the second conductive films 19 and 23 of the lower wiring layer and the upper wiring layer were created by the electrolytic plating method of the first embodiment, but ordinary DC electrolytic plating was used. It may be formed using a plating solution containing a surface brightener by a method. As a result, the first conductive films 18a, 2
The second conductive film 19 is formed by the second and third conductive films 1118 b.
．． The stress from 23 to the insulating film is relaxed.

■Method for manufacturing a semiconductor device according to the third embodiment Next, the method for manufacturing a semiconductor device according to the third embodiment will be explained in FIGS.
This will be explained with reference to h).

First, in order to form a conductive film by electrolytic plating, the fourth
[ff1(a) The contact balls (openings) 15a formed in the base insulating film (insulating film) I5 on the semiconductor substrate 14 and the buffer electrode 16 (conductor) are covered with a film thickness of approximately After forming the base conductive film 17 consisting of a 300-layer Ti film and an approximately 1000-layer Au film thereon, a Menki solution containing no surface brightening agent, such as Temperex 401 manufactured by Nippon Electroblating Co., Ltd., is applied.
A first conductive film 18a made of Au is formed by a normal electrolytic plating method using (trade name) (FIG. 4(b)).

Note that since this first conductive film 18a does not contain a surface brightener, it is usually soft.

Next, as shown in FIG. 1(a), the first conductive film 18a is coated with the plating solution 25 containing a surface brightener (additive) in the plating bath 24 using the DC power supply 28 and the pulse power supply 29. The voltage/current applied between the plating electrode 26a and the first
As shown in Figure (b), a second conductive film 19 made of an Au film is formed on the first conductive film 18a (conductor to be plated) by electrolytic plating, which is performed while alternating the direction of applied force. .

At this time, the second conductive film 19 has good coverage due to the action of the surface brightener that smooths out the unevenness of the surface (see Fig. 4).
C)).

Next, a third conductive film 18b made of Au is formed on the second conductive film 19 in the same manner as in FIG.
Note that this third conductive film 18b also does not contain a surface brightener and is therefore usually soft. 3 of the first conductive film 18a/second conductive film 19/third conductive film 18b.
The layers constitute a multilayer conductive film 31, and the multilayer conductive film 31 and the base conductive film 17 constitute a lower wiring layer (N conductor).

Next, after forming an interlayer insulating film 20 made of a PSG film or the like to cover the lower wiring layer, the interlayer insulating film 20 on the lower wiring layer is formed.
A pier hole (opening) 20a is formed in ((e) of the same figure).
).

Next, a base conductive film 21 and a first conductive film 22 which cover the peer hole 20a and constitute an upper wiring layer are formed using the same metal and method as in FIG. 4(b) (FIG. 4(f)).
.

Next, a second conductor tM23 is formed on the first conductor M22 using the same metal and method as in FIG.
)). Note that 2 of the first conductive film 22/second conductive film 23
The layers constitute a multilayer conductive film 32.

After that, the second conductive film 23. The first conductive film 22 and the base conductive film 21 are patterned to form an upper wiring layer (
Figure 1 (h).

As described above, according to the method for manufacturing a semiconductor device according to the third embodiment of the present invention, the first or third conductive film 18a or 18b created using a plating solution that does not contain a surface brightener is not enough. , the coverage deteriorates, but the second conductive film is formed using a plating solution containing a surface brightener on the first conductive film 22 or between the first conductive film 18a and the third conductive film 18b.
By forming the conductive film 23 or 19, the original coverage is maintained.

〔Effect of the invention〕

As described above, according to the method for manufacturing a semiconductor device of the present invention, since the current in the plating reservoir is passed alternately in forward and reverse directions, first, while the plating current is flowing in the forward direction, the surface brightener is applied to the coating material. The electroplating agent is electrodeposited on the convex portion of the conductive film, and the plating film is electrodeposited using this as a core, but while flowing in the opposite direction, the electrodeposited surface brightener is removed from the object to be plated. Therefore, the content of the surface brightener in the conductive film formed by repeating this process is drastically reduced.

Thereby, electrical resistance can be reduced.

Furthermore, since the electrodeposition is performed via a surface brightener, the coverage of the plating film is maintained as it was due to the action of the surface brightener.

Further, according to the semiconductor device of the present invention, the conductive film created using a plating solution that does not contain a surface brightener is provided closer to the insulating film. Furthermore, in the case of being covered with an interlayer insulating film, if the third conductive film on the top layer is also created using a plating solution that does not contain a surface brightener, the third conductive film will be in contact with the interlayer insulating film. It turns out. Currently, conductive films created using plating solutions that do not contain surface brighteners are soft, so
These conductive films hardly apply stress to the glabellar insulating film.

Furthermore, if a conductive film is formed using only a plating solution that does not contain a surface brightener, the coverage will deteriorate, so to prevent this, a method that does not contain a surface brightener is used.

A conductive film made using a liquid is formed between or on these conductive films.

Furthermore, since this conductive film is formed using the above method, electrical resistance can be reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the electrolytic plating method according to the first embodiment of the present invention. FIG. 2 is a diagram explaining the action of the electrolytic plating method according to the first embodiment of the present invention. FIG. , FIG. 4 is a sectional view illustrating a method for creating a multilayer wiring structure according to the second embodiment of the present invention, and FIG. , a diagram illustrating a conventional electrolytic plating method, a sixth section is a sectional view illustrating a conventional multilayer wiring structure, and FIG. 7 is a sectional view illustrating a conventional method for creating a multilayer wiring. [Explanation of symbols] 1.14...Semiconductor substrate, 2...Base insulating film, 2a...Contact hole, 3.16...Hanwha electrode, 4.7.17.21...Base conductive film Film, 5... First Au film (lower conductive film), 6... Interlayer insulating film, 6a... Pier hole, 8... Second Au film (upper conductive film), 9.24.・・・
Plating bath, 10.25... Plating solution, 11.26a, 26b-... Plating electrode, 12a...
Lower wiring layer, 12b... Upper wiring layer, 13.28... DC power supply, 15... Base insulating film (insulating film), 15a... Contact hole (opening), 18a, 2
2...First conductive film (conductor to be plated), 18b...
- Third conductive film, 19.23... Second conductive film (conductive film), 20...
Interlayer insulating film (insulation H), 20a... Pier hole (opening), 27... Conductive material to be plated, 29... Pulse power source, 30... Conductor, 31.32... Multilayer conductive film , 33... Surface brightener (additive), 34... Conductive film, 35... Convex portion.

Claims (4)

[Claims] (1) One plating electrode in a plating solution containing additives,
A conductive material to be plated connected to the other plating electrode is inserted, and a voltage/current with alternating directions is applied between the plating electrodes to form a conductive film on the conductive material to be plated. A method for manufacturing a semiconductor device. (2) A semiconductor device having a multilayer conductive film of two or more layers formed by electrolytic plating on a conductive film to be plated covering an opening in an insulating film on a conductor, the bottom layer of the multilayer conductive film being formed by electrolytic plating. The first conductive film is formed using a plating solution containing no additives, and the second conductive film on the first conductive film is formed using a plating solution containing additives. A semiconductor device characterized in that it is a semiconductor device. (3) A semiconductor device having a multilayer conductive film of three or more layers formed by electrolytic plating on a conductive film to be plated that covers an opening in an insulating film on a conductor, wherein the lowest layer of the multilayer conductive film is The first conductive film and the third conductive film as the uppermost layer are formed using a plating solution that does not contain an additive, and the additive is present between the first conductive film and the third conductive film. A semiconductor device characterized in that it is formed using a plating solution containing. (4) Either claim 2 or claim 3, wherein the second conductive film formed using the plating solution containing the surface brightener is formed by the method according to claim 1. The semiconductor device described in .