JP2001240998A - Plating treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plating treatment device which is effective for forming metallic films free of voids within grooves or inter-layer connecting holes. SOLUTION: This device is constituted to have a plating liquid supplying vessel 10 for supplying the plating liquid, plural plating treatment vessels 12 which are internally installed with substrates and are used to execute a plating treatment and plating liquid circulating piping 11 for connecting the plating liquid supplying vessel 10 and the plating treatment vessels 12 and for circulating the plating liquid. The plating treatment vessels 12 are respectively independently provided with thermometers 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating apparatus used in a process for forming a buried wiring, an interlayer connection hole and the like by a plating method.

[0002]

2. Description of the Related Art Sputtering and CVD are widely used as techniques for depositing metal films for forming wiring and interlayer connection holes in semiconductor devices. However, these methods involve applying a large amount of energy to the metal compound to release the metal or separate the metal from the corresponding metal compound to deposit the metal on the surface on which the semiconductor element is formed. And the process is complicated. When the sputtering method is used, sufficient coverage may not be obtained. As a method for solving these problems, deposition of a metal film by an electrolytic plating method has recently attracted attention.

Hereinafter, a conventional method for manufacturing a semiconductor device will be described with reference to FIGS.

[0004] First, after an insulating film 2 is formed on a silicon substrate 1, a groove 5 is formed at a predetermined location. Next, Ti
A barrier metal film 3 made of N is deposited by a sputtering method. The thickness is, for example, 200 °. Subsequently, a seed metal film 4 made of copper for growing copper plating is deposited thereon by sputtering (FIG. 5).
(A)). The sputtering conditions are, for example, a substrate temperature of 0
C., the sputtering power was 2 kW, the pressure was 2 mTorr, and the distance between the target and the substrate was 60 mm.

[0005] Next, the substrate is immersed in an aqueous solution of copper sulfate at normal temperature to perform plating.

Then, the plated substrate is left at room temperature. This stabilizes the copper structure (FIG. 5).
(B)). Hereinafter, this processing is referred to as self-annealing.
The time required for the self-annealing is usually about 50 to 80 hours.

Thereafter, the surface of the substrate is flattened by chemical mechanical polishing (CMP) to form a buried copper wiring.

[0008]

However, the above prior art has the following problems.

First, there is a problem that voids are generated inside grooves and holes. The voids are caused by shrinkage of the plated copper in the self-annealing step.
Plated copper generally has a sparse structure when plated. And, through self-annealing,
As the grains grow, the copper structure approaches a thermodynamically stable structure. During this process, copper shrinks,
As shown in FIG. 5B, a void is generated inside the groove.

Second, there is a problem that minute grains of a seed metal film provided for forming a plating layer remain even after self-annealing, thereby deteriorating the reliability of the device.

The present invention provides a process for solving the above problems,
That is, an object of the present invention is to provide a plating apparatus which can be suitably used in a process for preventing generation of voids in a groove or a hole when a buried wiring or an interlayer connection hole is formed by plating.

[0012]

Before describing the plating apparatus of the present invention, first, process examples (i) to (vi) related to the present invention will be described.

(I) a step of forming an insulating film on a semiconductor substrate and providing a groove or hole at a predetermined position in the insulating film; a step of forming a barrier metal film so as to fill the groove or hole; Forming a seed metal film on the barrier metal film formed inside the hole, forming a first plating film using a metal material on the seed metal film, and performing first annealing. A semiconductor device comprising: a step of performing a predetermined time; a step of forming a second plating film made of the metal material on the first plating film; and a step of performing a second annealing for a predetermined time. Manufacturing method.

Conventionally, plating for forming embedded metal wiring has been performed in one step from the viewpoint of productivity and the like. On the other hand, in the method of manufacturing a semiconductor device, the formation of the plating film is performed in two stages (hereinafter, appropriately referred to as a “split plating method”), thereby preventing the generation of voids in the groove or the hole. . That is, it is possible to prevent voids inside holes for forming buried wiring and holes for forming interlayer connection holes. In the method of manufacturing a semiconductor device, the first annealing is performed after the first plating. This annealing is performed at a stage where the thickness of the plating film is small. Therefore, since the plated metal has a small absolute amount, its shrinkage is suppressed, and the frequency of occurrence of voids can be reduced. Further, even if voids occur once, the thickness of the plating film is thin in the first annealing stage, so that the distance from the location where the voids occur to the plating film surface is short, and the voids easily disappear. For the above reasons, generation of voids inside the groove or hole is prevented.

The annealing in the method for manufacturing a semiconductor device may be self-annealing at room temperature or heating annealing performed at a high temperature of 300 ° C. or higher. In the case of heat annealing, there is an advantage that the annealing time can be shortened. For example, when the heating temperature is set to 300 ° C., the annealing time is about 30 minutes.

In the method of manufacturing a semiconductor device, the thickness of the first plating film may be 0.1 to 0.1 times the width of the groove or hole.
Preferably it is 5 times.

(Ii) forming an insulating film on the semiconductor substrate and providing a groove or hole at a predetermined position in the insulating film; forming a barrier metal film so as to fill the groove or hole; A step of forming a seed metal film on the barrier metal film formed inside the hole and a step of forming a plating film using a metal material on the seed metal film and then annealing for a predetermined time; And forming the metal plating film at a plating temperature of 65 to 100 ° C.

As described above, in order to suppress the generation of voids in the grooves or holes, it is effective to suppress the shrinkage of the plated metal film. The above-described method of manufacturing a semiconductor device achieves this by setting the plating temperature to a high temperature of 65 to 100 ° C. (hereinafter, appropriately referred to as “high-temperature plating method”). The plating metal film for forming the buried wiring or the like is usually formed at a room temperature or a low temperature of 60 ° C. or lower. Particularly when copper is used, it is usually performed at room temperature. On the other hand, in the method of manufacturing a semiconductor device, since the plating temperature is set to a high temperature of 65 ° C. or higher, the grains grow simultaneously with the film formation, so that the contraction of the plated metal film after the film formation due to the grain growth is significantly reduced. In addition, voids are prevented and the annealing time is shortened. This effect is 65 ° C
The temperature is particularly remarkable at the above temperature, but more remarkable at 80 ° C. or more. If the plating temperature exceeds 100 ° C., foaming during plating tends to occur, which is not preferable.

(Iii) forming an insulating film on the semiconductor substrate and providing a groove or hole at a predetermined position in the insulating film; forming a barrier metal film so as to fill the groove or hole; Forming a seed metal film on the barrier metal film formed inside the hole; and forming the seed metal in a state in which the semiconductor substrate is deformed in a convex shape so that a central portion of the surface to be plated protrudes. A method for manufacturing a semiconductor device, comprising: a step of forming a plating film using a metal material on a film; and a step of performing annealing for a predetermined time.

In the conventional plating method, when a metal material causing self-annealing is used, tensile stress remains in the plating film. This is considered to be due to the fact that the plating film shrinks with the growth of the grain size of the plating metal in the self-annealing step after the plating film formation.

In other words, it is considered that the tensile stress in the plating film acts in a direction to prevent the contraction of the plating film, and inhibits the self-annealing accompanied by the contraction of the plating film. In that case, if the plating film is formed such that a compressive stress is generated in the film, it is expected that the stress will act in a direction in which the contraction of the plating film is promoted and self-annealing will be promoted. The method for manufacturing a semiconductor device is based on such an idea. In the method of manufacturing a semiconductor device, the plating film is formed in a state in which the semiconductor substrate is deformed in a convex shape so that the central portion of the surface to be plated protrudes, thereby compressing the plating film into the film. It is formed so as to generate stress. By doing so, the self-annealing time is shortened, and the generation of voids inside the grooves or holes is prevented. The “state in which the semiconductor substrate is deformed in a convex shape so that the central portion of the surface to be plated protrudes” means that the central portion of the surface to be plated protrudes, for example, as the substrate 21 in FIG. A state in which convex warpage is added.

(Iv) forming an insulating film on the semiconductor substrate and providing a groove or hole at a predetermined position in the insulating film; forming a barrier metal film so as to fill the groove or hole; Forming a seed metal film on the barrier metal film formed inside the hole so that a compressive stress remains in the seed metal film; and forming a plating film on the seed metal film using a metal material. Performing a predetermined time annealing after forming the semiconductor device.

Conventionally, a seed metal film for forming plating has been formed by a sputtering method or the like. In this case, tensile stress remains in the seed metal film. It is presumed that when such tensile stress remains, the stress acts in a direction in which the contraction of the plating film formed on the seed metal film is suppressed. Therefore, it is considered that the residual tensile stress in the seed metal film inhibits self-annealing accompanied by shrinkage of the plating film. Therefore, it is considered that if compressive stress is left in the seed metal film, stress acts in a direction in which contraction of the plating film is promoted, and self-annealing is promoted. The above-described method of manufacturing a semiconductor device is based on such a concept, and the seed metal film has a residual compressive stress, thereby shortening the self-annealing time and generating voids in the grooves or holes. Is prevented.

There are various means for leaving the compressive stress in the seed metal film. For example, the following means is preferable.

A first means is a method of manufacturing a semiconductor device, wherein the seed metal film is formed by a sputtering method, wherein the seed metal film is formed in a state where the semiconductor substrate is deformed in a convex shape toward a target. It is characterized by doing. By doing so, when the substrate is removed from the sputtering apparatus, a compressive stress remains in the seed metal film.

The second means is characterized in that the seed metal film is formed by a collimated sputtering method. According to the study of the present inventors, it has been confirmed that when the collimated sputtering method is used, compressive stress remains in the seed metal film.

(V) forming an insulating film on the semiconductor substrate and providing a groove or hole at a predetermined position in the insulating film; forming a barrier metal film so as to fill the groove or hole; Forming a seed metal film on the barrier metal film formed inside the hole; and forming a plating film on the seed metal film using a metal material, wherein the seed metal film is formed by ( 111) A method for manufacturing a semiconductor device, which is oriented.

(Vi) A step of forming an insulating film on a semiconductor substrate and providing a groove or a hole at a predetermined position of the insulating film, and forming a Ti film and a TiN film in this order so as to fill the groove or the hole. Process and the TiN formed inside the groove or hole.
Forming a seed metal film on the film; and forming a plating film on the seed metal film using a metal material, wherein the seed metal film has a (111) orientation. Semiconductor device manufacturing method.

In the conventional process, the seed metal film has a low (111) orientation. For this reason, the fine grains of the seed metal film are likely to remain after annealing because of the property that the plated metal film formed thereon, for example, the Cu film has a property of being oriented to (111) orientation.
On the other hand, in the method for manufacturing a semiconductor device, since the seed metal film has the (111) orientation, the remaining fine grains can be effectively suppressed. (11
1) As a method of forming a seed metal film having an orientation, for example, a Ti film and a TiN film are formed in this order so as to fill a groove or a hole provided in an insulating film, and a seed metal film is formed thereon. Formation method. As described above, by forming the Ti film first and then forming the TiN film, the orientation of the TiN film can be improved, and as a result, the seed metal film formed thereon has the (111) orientation. can do.

In each of the above-described methods of manufacturing a semiconductor device, it is preferable that the material of the seed metal film and the metal material are made of Cu, Ag, or an alloy thereof. This is because these metal materials cause self-annealing and can form a favorable metal film suitable for a semiconductor device. Also, these metal materials have low resistance,
In addition, while there is an advantage that there are few problems such as electromigration, there is a problem that voids are easily generated in the plating and self-annealing steps. Therefore, when the above metal material is used, the effect is more remarkably exhibited.

The above-described semiconductor device manufacturing methods can be combined with each other. For example, in the division plating method, the first plating film and / or the second plating film may be formed by a high-temperature plating method.
Further, in the case of a split plating method, a high-temperature plating method or a manufacturing method combining these, a plating process is performed in a state where the semiconductor substrate is deformed in a convex shape, or a seed metal film is formed so that a compressive stress remains. You can also. Since these methods do not impair the advantages of the other methods, a further synergistic effect can be obtained by the combination, and the effect of preventing voids and the effect of shortening the self-annealing time can be made more remarkable.

Next, the present invention will be described.

According to the present invention, a plating solution supply tank for supplying a plating solution, a plurality of plating tanks for installing a substrate therein and performing plating on the substrate, A plating apparatus, comprising: a tank and a plating tank connected to each other; a plating solution circulation pipe for circulating a plating solution; and each of the plating tanks independently provided with a temperature adjusting means. Is provided.

In this plating apparatus, a temperature adjusting means is provided in each plating tank. Therefore, a plurality of plating processes having different processing temperatures can be simultaneously performed by one plating apparatus, and productivity is improved. For example, a plating process performed at room temperature and a high-temperature plating process proposed in the present application can be performed simultaneously by one plating apparatus. In the method proposed in the present application, in which plating is performed twice, when the first and second plating processes are performed at different temperatures, it is efficient to use the plating apparatus. In the case where the above plating apparatus is used, the required number of plating apparatuses can be reduced, which is effective for space saving of the installation place of the apparatus.

In the present invention, a plating solution supply tank for supplying a plating solution, a plurality of plating tanks for installing a substrate therein and performing plating treatment on the substrate, The plating bath is connected to the plating bath, and has a plating solution circulation pipe for circulating a plating solution.The plating bath includes an electrode and a substrate holder for disposing a substrate to be processed in opposition to the electrode. And the substrate holder comprises:
It may be configured to include a unit for giving a warp to the substrate to be processed. Here, “giving a warp” means giving a substrate a concave or convex deformation.

In the above plating apparatus, the means for giving a warp to the substrate to be processed is a pressing means for applying pressure to the substrate to be processed from the back side of the surface to be processed. Different pressures may be applied to the central portion of the processing substrate and the end of the substrate to be processed.

These plating apparatuses are apparatuses suitable for carrying out the above-described method of manufacturing a semiconductor device including the step of forming a plating film in a state where the semiconductor substrate is deformed into a convex shape. According to the plating apparatus described above, it is possible to perform the plating process by deforming the substrate in a convex shape without deteriorating the quality of the substrate. As a result, the self-annealing time can be shortened, and the generation of voids inside the grooves or holes can be prevented. In particular, according to the plating apparatus having the above-described pressurizing means,
By adjusting the amount of pressurization, the amount of deformation (the degree of warpage) of the substrate can be accurately controlled, so that the amount of deformation of the substrate can be set to the most effective value for shortening the self-annealing time. It becomes possible.

The means for warping the substrate in the plating apparatus may be, for example, one that deforms the substrate in a convex shape so that the center of the substrate protrudes toward the electrode. Can be. The pressurizing means in the plating apparatus may be configured to apply pressure such that the pressure applied to the center of the substrate to be processed is higher than the pressure applied to the edge of the substrate to be processed.

The following sputtering apparatuses (a) and (b) can be used together with the plating apparatus of the present invention. (A) a chamber provided with an exhaust system, a target disposed at a predetermined position in the chamber, and an electrode for generating a sputter discharge for sputtering the target;
A sputtering apparatus comprising: a substrate holder that holds a substrate to be processed in parallel with the target so as to face the target; wherein the substrate holder includes a unit that warps the substrate to be processed.

Here, "to give a warp" means to give a concave or convex deformation to the substrate. (B) In the sputtering apparatus, the means for giving a warp to the substrate to be processed is a pressing means for applying pressure to the substrate to be processed from the back surface of the surface to be processed.
A sputtering apparatus for applying different pressures to a central portion of the substrate to be processed and an end of the substrate to be processed.

The self-annealing of the plating film is promoted by leaving a compressive stress in the seed metal film. As described above, it is effective to form the seed metal film in a state in which the substrate to be processed is deformed in a convex shape toward the target as described above.
The above sputtering apparatus is a sputtering apparatus for performing this method. When this sputtering apparatus is used, sputtering is performed in a state where the substrate is warped in a convex shape, so that when the substrate is removed from the apparatus, a compressive stress is generated in the seed metal film.
If a plating film is formed thereon and self-annealing is performed, the self-annealing time can be reduced. This sputtering apparatus has an advantage that the magnitude of the compressive stress can be adjusted as desired by controlling the warpage of the substrate.

In particular, according to the sputtering apparatus having the above-mentioned pressurizing means, the substrate can be warped without difficulty.
A good seed metal film can be formed. further,
By adjusting the amount of pressurization, the amount of deformation (the degree of warpage) of the substrate can be accurately controlled, so that the amount of deformation of the substrate can be set to the most effective value for shortening the self-annealing time. It becomes possible.

The means for warping the substrate in the sputtering apparatus may be, for example, one that deforms the substrate in a convex shape so that the central portion of the substrate protrudes toward the electrode. it can. In addition, the pressurizing means in the sputtering apparatus can pressurize the substrate so that the pressure applied to the center of the substrate to be processed is higher than the pressure applied to the end of the substrate to be processed.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of a plating apparatus of the present invention and a process related thereto will be described.

(Example 1) This example is an example in which the plating treatment is performed twice. Hereinafter, description will be made with reference to FIG.

First, after an insulating film 2 is formed on a silicon substrate 1, a groove 5 is formed at a predetermined position. Next, Ti
A barrier metal film 3 made of N is deposited by a sputtering method. The thickness is, for example, 200 °. Subsequently, a seed metal film 4 made of copper for growing copper plating is deposited thereon by a sputtering method (FIG. 1).
(A)). The sputtering conditions are, for example, a substrate temperature of 0
C., the sputtering power was 2 kW, the pressure was 2 mTorr, and the distance between the target and the substrate was 60 mm.

Next, the substrate is immersed in an aqueous solution of copper sulfate at normal temperature (about 15 to 30 ° C.) to form a first plating film 6 (FIG. 1B). The thickness of the first plating film 6 is preferably 0.1 to 0.5 times the width of the groove 5, more preferably the groove 5
The width is set to 0.2 to 0.4 times the width. If the film thickness is too large, voids cannot be sufficiently prevented. If the film thickness is too thin, most of the inside of the groove 5 must be buried by the second plating, and the effect of preventing voids is reduced.

The first annealing is performed on the substrate plated as described above. This annealing is performed at room temperature (about 15 to 30 ° C.) for preferably 2 to 10 hours, more preferably 4 to 8 hours. The annealing time is appropriately set according to the thickness of the first plating film 6. This self-annealing stabilizes the copper structure, and copper having a large grain size can be obtained. Note that annealing may be performed by heating. For example, heat annealing at 300 ° C. for 30 minutes can be performed.

Subsequently, the substrate is immersed in an aqueous solution of copper sulfate at normal temperature to form a second plating film 7. Second plating film 7
Are formed so that the groove 5 is completely filled with copper (FIG. 1).
(C)).

Thereafter, a second annealing is performed at normal temperature.
The annealing time is appropriately set according to the thickness of the second plating film 7. This self-annealing stabilizes the copper structure, and copper having a large grain size can be obtained. In this case, as in the first annealing, heat annealing can be performed.

In the case of self-annealing at room temperature, the total time of the first and second annealing is preferably 1
0 to 40 hours, more preferably 20 to 35 hours. According to this method, a sufficient annealing effect can be obtained even in such a short time, and the above time is preferable from the viewpoint of production efficiency.

After that, the barrier metal film 3 and the buried metal are polished by CMP to flatten the substrate surface, thereby forming the buried wiring 8 (FIG. 2).

(Example 2) This example is an example in which plating is performed at a high temperature. Hereinafter, description will be made with reference to FIG.

First, after an insulating film 2 is formed on a silicon substrate 1, a groove 5 is formed at a predetermined position. Next, Ti
A barrier metal film 3 made of N is deposited by a sputtering method. The thickness is, for example, 200 °. Subsequently, a seed metal film 4 made of copper for growing copper plating is deposited thereon by a sputtering method (FIG. 3).
(A)).

The sputtering conditions are, for example, a substrate temperature of 0 ° C., a sputtering power of 2 kW, a pressure of 2 mTorr, and a distance between the target and the substrate of 60 mm.

Next, the substrate is immersed in an aqueous solution of copper sulfate at a high temperature of 65 to 100 ° C. to form a plating film 9 (FIG. 3).
(B)). The plating film 9 is formed so as to fill the entire groove 5. By forming the plating film at such a high temperature, a good metal film with less shrinkage in the annealing step can be obtained. Thereby, the generation of voids can be suppressed and the self-annealing time can be shortened.

Annealing is performed on the substrate plated as described above. The annealing conditions are 1 to 40 at room temperature.
Time. More preferably, it is 1 to 10 hours. Since the plating film is formed at a high temperature, the annealing time is short.

Thereafter, the barrier metal film 3 and the buried metal are polished by CMP to flatten the substrate surface, thereby forming a buried wiring (not shown).

(Example 3) FIG. 6 is a view showing a schematic structure of the plating apparatus. The plating solution supply tank 10 is filled with a plating solution such as an aqueous solution of copper sulfate. A circulation pump 15 is provided to supply the plating solution to each plating tank 12 through the plating solution circulation pipe 11. Each of the plating tanks is independently provided with a heater 13,
A temperature adjusting means including a thermometer 20 and a temperature control device 14 is provided. Therefore, a plurality of plating processes having different processing temperatures can be simultaneously performed by one plating apparatus. The conventional plating apparatus differs in that a temperature adjusting means is provided in a plating solution supply tank.

As shown in the figure, the temperature adjusting means includes a heating means and a temperature control means, and may include a cooling means as required. As the heating means, a heater or the like can be used. On the other hand, a water-cooled jacket or the like can be used as the cooling means. As the temperature control means, for example, a PID type temperature control device can be used.

In this plating apparatus, a plating solution supply tank is also provided with a temperature adjusting means independent of the plating tank. This temperature adjusting means comprises a cooling means 16 and a temperature control device 14. By providing such a temperature adjusting means, when the plating solution whose temperature has been adjusted to various temperatures in each plating tank returns to the plating solution supplying means, it is controlled to a constant temperature again. This facilitates temperature adjustment in each plating tank.

(Example 4) This example is an example of a method of performing a plating process in a state where a substrate is deformed into a convex shape.

FIG. 3 shows steps of a method for manufacturing a semiconductor device according to this example. First, after an insulating film 2 is formed on a silicon substrate 1, a groove 5 is formed at a predetermined position. Next, Ti
A barrier metal film 3 made of N is deposited by a sputtering method. The thickness is, for example, 200 °. Subsequently, a seed metal film 4 made of copper for growing copper plating is deposited thereon by a sputtering method (FIG. 3A).

Next, the substrate is immersed in an aqueous solution of copper sulfate at normal temperature to form a plating film 9. The plating film 9 is formed so as to fill the entire groove 5.

At this time, the plating apparatus shown in FIGS. 6 to 8 is used. FIG. 6 is a diagram showing a schematic structure of a plating apparatus according to this example. The plating solution supply tank 10 is filled with a plating solution such as an aqueous solution of copper sulfate. A circulation pump 15 is provided to supply the plating solution to each plating tank 12 through the plating solution circulation pipe 11.
Each plating tank is independently provided with a temperature adjusting means including a heater 13, a thermometer 20, and a temperature controller 14. FIG. 7 shows the plating bath 1 in FIG.
2 is an enlarged view of FIG. The plating tank has an anode 27,
A substrate holder 22 for arranging the substrate 21 opposite thereto;
And The substrate holder 22 includes a pressing unit that deforms the substrate 21 in a convex shape so that the central portion of the substrate 21 projects toward the anode 27. In the figure, a thermometer, a heater, and the like are omitted.

A more detailed structure of the pressing means will be described with reference to FIG. The substrate holder 22 located on the back surface of the substrate is divided into a plurality of rooms concentrically as shown in the figure. The space in each room is occupied by a water pillow-shaped pressure bag 23 filled with a pressure medium. In this example, this pressure bag 2
3 has a donut shape. As a material of the outer cover, for example, a heat-resistant resin such as a fluororesin is used. The pressurized medium to be filled in the pressurized bag 23 is not particularly limited. Each of the pressurized bags 23 is connected to a pressurized medium supply source 25 via a pressure adjusting valve 24. Different pressures are applied to the respective pressurized bags by the pressurized medium supply source 25 and the pressure adjusting valve 24 so that the highest pressure is applied to the pressurized bags arranged on the back surface at the center of the substrate so that they protrude most. It has been adjusted (FIG. 8). As a result, the substrate can be formed in a convex shape toward the anode 27 as shown in FIG.

When plating is performed in a state where the substrate is warped in a convex shape, a compressive stress is generated in the plating film when the substrate is removed from the apparatus.

Thereafter, annealing is performed on the plated substrate. Annealing conditions are normal temperature for 10 to 40 hours. Since the seed metal film 4 has a residual compressive stress, a sufficient annealing effect can be obtained even with such a short annealing time. Further, the barrier metal film 3 and the buried metal are polished by CMP to flatten the substrate surface, thereby completing the buried wiring.

In this embodiment, a method using a pressurized bag is shown as a means for making the substrate warped convexly when forming the plating film. However, other methods can be used. For example, a method of pressing the back surface of the substrate with a plurality of bars can be used.

Example 5 This example is an example of a manufacturing method including a step of forming a seed metal film in a state where a substrate is deformed in a convex shape.

FIG. 3 shows steps of a method for manufacturing a semiconductor device according to this example. First, after an insulating film 2 is formed on a silicon substrate 1, a groove 5 is formed at a predetermined position. Next, Ti
A barrier metal film 3 made of N is deposited by a sputtering method. The thickness is, for example, 200 °. Subsequently, a seed metal film 4 made of copper for growing copper plating is deposited thereon by a sputtering method (FIG. 3A).

At this time, the sputtering apparatus shown in FIG. 9 is used. The sputtering apparatus includes a vacuum chamber 30 provided with an exhaust system 34, a target 31 disposed at a predetermined position inside the vacuum chamber 30, an electrode 32 for generating a sputter discharge for sputtering the target 31, and a substrate 21 31 and a substrate holder 22 that is opposed to and held in parallel. A discharge power supply 33 is connected to the electrode 32. The substrate holder 22 includes a pressing unit that applies pressure to the substrate 21 from the back surface. This pressurizing means pressurizes the substrate 21 so that the pressure applied to the central portion of the substrate 21 is higher than the pressure applied to the end portion.
The substrate 21 is deformed in a convex shape so that the central portion of the substrate 21 projects toward the target 31. The structure of the pressing means is the same as the structure described with reference to FIG. 7 in the fourth example.

When sputtering is performed in a state where the substrate is warped in a convex shape, a compressive stress is generated in the seed metal film 4 when the substrate is removed from the apparatus.

Next, the substrate is immersed in an aqueous solution of copper sulfate at normal temperature to form a plating film. The plating film is formed so as to fill the entire groove 5. Thereafter, annealing is performed on the plated substrate. The annealing condition is 10 at room temperature.
４０40 hours. Since the seed metal film 4 has a residual compressive stress, a sufficient annealing effect can be obtained even with such a short annealing time.

Thereafter, the barrier metal film 3 and the buried metal are polished by CMP to flatten the substrate surface, thereby forming a buried copper wiring.

In this example, a method using a pressurized bag was shown as a means for making the substrate warped convexly when forming the seed metal film 4 by sputtering. However, other methods are used. It can also be used. For example, a method of pressing the back surface of the substrate with a plurality of bars can be used.

Example 6 In Example 5, a seed metal film 4 was formed by sputtering with the substrate to be processed warped, thereby generating a residual compressive stress in the seed metal film 4.
As another method, a residual compressive stress can be generated by using a collimated sputtering method in which the distance between the target and the substrate is increased.

Although it is not always clear why the collimated sputtering method generates a compressive stress, the kinetic energy of the sputtered particles reaching the substrate surface in the direction perpendicular to the substrate becomes a certain value or more. It is presumed that a relatively high sputtered film was obtained.

The conditions for the collimate sputtering include, for example, a distance between the target and the substrate of 100 to 300 mm and an aspect ratio of the collimator, that is, a ratio of the depth to the diameter of the hole of 1 to 2. Also, the sputter power should be 1 to
30 kW and a sputter pressure of 1 to 10 mTorr.

[0080]

The following is an example of a process to which the plating apparatus of the present invention can be suitably applied.

(Process Example 1) This process example is an example in which the plating process is divided into two times and the second plating process is performed at a high temperature. Hereinafter, description will be made with reference to FIG.

First, after an insulating film 2 was formed on a silicon substrate 1, a groove 5 having a width of about 0.3 μm and a depth of 0.5 μm was formed at a predetermined location. Next, a barrier metal film 3 made of TiN was deposited on the entire surface by a sputtering method. The film thickness is 2
00 °. Subsequently, a seed metal film 4 made of copper for growing copper plating was deposited thereon by a sputtering method (FIG. 1A). The sputtering conditions were: substrate temperature 0 ° C., sputtering power 2 kW, pressure 2 mTor.
r, and the distance between the target and the substrate was 60 mm.

Next, the substrate was immersed in an aqueous solution of copper sulfate at a liquid temperature of about 25 ° C. to form a first plating film 6. The thickness of the first plating film 6 was 90 nm in the flat portion (FIG. 1B).

The substrate thus plated was subjected to a first annealing at 25 ° C. for 5 hours.

Subsequently, the substrate was immersed again in a solution having the same composition as the above-mentioned aqueous solution of copper sulfate at a solution temperature of 70 ° C. to form a second plating film 7. The second plating film 7 was formed so as to have a film thickness of 5 μm and completely fill the groove 5 with copper (FIG. 1C).

Next, a second annealing was performed at room temperature for 25 hours.

Thereafter, the barrier metal film 3 and the buried metal were polished by CMP to flatten the substrate surface, thereby forming a buried wiring 8 (FIG. 2).

When the cross section of the manufactured wiring structure was observed with a scanning electron microscope, it was confirmed that wiring in a good embedded state without voids was formed.

(Process Example 2) A wiring structure was produced in the same manner as in Process Example 1, except that the seed metal film 4 was formed using the sputtering apparatus shown in FIG.

When the substrate was set on the substrate holder shown in FIG. 9, the warpage of the substrate was set to about 1 mm. That is, the central portion of the substrate is projected about 1 mm from the end.

The sputtering conditions were as follows: the distance between the target and the substrate was 120 mm, the sputtering power was 10 kW, the sputtering pressure was 50 mTorr, and the substrate temperature was 0 ° C.

When the film stress of the sputtered film separately manufactured under the above conditions was measured by X-ray diffraction, the film stress was a stress in the compression direction, and was about 1 × 10 ⁹ dyne / cm ² .

After the seed metal film 4 is formed by the sputtering method, the first and second plating films 7 are formed in the same manner as in the process example 1, and the barrier metal film 3 and the buried metal are polished by the CMP and the substrate surface is polished. To form a buried copper wiring.

When the cross section of the manufactured wiring structure was observed with a scanning electron microscope, it was confirmed that a wiring having a good buried state without voids was formed.

(Process Example 3) Process Example 1 except that the seed metal film 4 was formed by the collimated sputtering method.
A wiring structure was produced in the same manner as described above.

The conditions for the collimate sputtering were such that the distance between the target and the substrate was 200 mm, and the aspect ratio of the collimator, that is, the ratio of the depth to the diameter of the hole was 1.
Further, the sputtering power is set to 10 kW and the sputtering pressure is set to 50.
mTorr, and the substrate temperature was 0 ° C.

When the film stress of the sputtered film separately formed under the above conditions was measured by X-ray diffraction, the film stress was a stress in the compression direction, and was about 1 × 10 ⁹ dyne / cm ² .

After the seed metal film 4 is formed by the sputtering method, the first and second plating films 7 are formed in the same manner as in the process example 1, and the barrier metal film 3 and the buried metal are polished by the CMP and the substrate surface is polished. To form a buried copper wiring.

When the cross section of the manufactured wiring structure was observed with a scanning electron microscope, it was confirmed that a good embedded wiring without voids was formed.

[0100]

As described above, according to the plating apparatus of the present invention, since the temperature adjusting means is provided in each plating tank, a plurality of plating processes having different processing temperatures can be performed by one plating apparatus. Can be done simultaneously,
Productivity can be improved.

In this plating apparatus, plating can be performed with the substrate warped in a convex shape. By doing so, a desired compressive stress can be generated in the plating film. Thereby, the self-annealing time can be shortened.

[Brief description of the drawings]

FIG. 1 is a process sectional view of a method for manufacturing a semiconductor device.

FIG. 2 is a process sectional view of the method for manufacturing the semiconductor device;

FIG. 3 is a process sectional view of the method for manufacturing the semiconductor device;

FIG. 4 is a process sectional view of the method for manufacturing the semiconductor device;

FIG. 5 is a process sectional view of a conventional method for manufacturing a semiconductor device.

FIG. 6 is a schematic view of a plating apparatus of the present invention.

FIG. 7 is a schematic view of a plating apparatus.

FIG. 8 is a view for explaining a structure of a substrate holder of the plating apparatus.

FIG. 9 is a schematic diagram of a sputtering apparatus.

[Explanation of symbols]

 Reference Signs List 1 silicon substrate 2 insulating film 3 barrier metal film 4 seed metal film 5 groove 6 first plating film 7 second plating film 8 embedded wiring 9 plating film 10 plating solution supply means 11 plating circulation pipe 12 plating treatment tank 13 heating Means 14 Temperature control means 15 Circulation pump 16 Void 20 Thermometer 21 Substrate 22 Substrate holder 23 Pressure bag 24 Pressure regulating valve 25 Pressurized medium supply source 27 Anode 30 Vacuum chamber 31 Target 32 Electrode 33 Discharge power supply 34 Exhaust system

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/3205 H01L 21/88 M

Claims (1)

[Claims] 1. A plating solution supply tank for supplying a plating solution, a plurality of plating tanks for installing a substrate therein and performing plating on the substrate, the plating solution supply tank and the plating A plating solution circulating pipe for circulating a plating solution, the plating solution circulating pipe being connected to the treatment bath, wherein a temperature adjusting means is independently provided in each plating bath.