JPH11246978A - Plating device for substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plating device for a substrate in which the compsn. of a plating soln. in each occation is automatically analyzed and can swiftly be displayed on a monitor. SOLUTION: This is a plating device for a substrate in which a substrate is dipped into a plating soln. to apply plating on the surface of the substrate and has sampling means 17 and 20 sampling the plating soln. 10 with a certain period, an automatic analyzing means 22 automatically analyzing the components in the sampled plating soln. and a monitor displaying means 30 displaying the analyzed result by the automatic analyzing means 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating apparatus for a substrate, and more particularly to a plating apparatus for a substrate used for filling a wiring recess formed in a semiconductor substrate with a metal such as copper.

[0002]

2. Description of the Related Art Conventionally, in order to form a wiring circuit on a semiconductor substrate, a conductor is formed on the substrate surface by sputtering or the like, and then a chemical dry etching is performed using a pattern mask such as a resist. Unnecessary portions of the film were removed.

[0003] Materials for forming a wiring circuit include:
Aluminum (Al) or an aluminum alloy has been used. However, as the degree of integration of the semiconductor increases, the wiring becomes thinner, the current density increases, and thermal stress and temperature rise occur. This becomes more remarkable as the thickness of Al or the like becomes thinner due to stress migration or electromigration, and finally, there is a risk of disconnection or short circuit.

Therefore, in order to avoid excessive heat generation due to energization, a material such as copper having higher conductivity is required to be used for forming the wiring. However, it is difficult to dry-etch copper or its alloy, and it is difficult to employ the above-described method of forming a pattern after forming the entire surface. Therefore, a step of forming a wiring groove in a predetermined pattern in advance and filling the groove with copper or an alloy thereof may be considered. According to this, a step of removing the film by etching is unnecessary, and a polishing step for removing a surface step may be performed.
Further, there is an advantage that a portion called a plug that connects the upper and lower sides of the multilayer circuit can be formed at the same time.

However, such wiring grooves or plugs have a considerably high aspect ratio (ratio of depth to diameter or width) as the wiring width becomes finer. It was difficult. In addition, a vapor phase growth (CVD) method is used as a film forming means of various materials. However, it is difficult to prepare an appropriate gaseous raw material with copper or its alloy, and when an organic raw material is used. However, there is a problem that carbon (C) is mixed into the deposited film to increase the migration property.

[0006]

Therefore, there has been proposed a method of immersing a substrate in a plating solution to perform electroless or electrolytic plating. In the film formation by such plating, it becomes possible to uniformly fill the wiring groove having a high aspect ratio with metal. However, in order to perform such plating stably, the concentration of each component in the plating solution, whose value fluctuates every moment at the same time as the plating process, is analyzed, and based on this analysis result, an appropriate amount of the shortage is supplied. In addition, it is necessary to maintain the plating solution at a normal composition. In particular, in reduction plating using a catalyst such as electroless copper plating, the management width of each component is generally narrow, and if the balance of the components is lost, the plating solution will self-decompose. Become.

For this reason, it is conceivable to periodically sample the plating solution used in the plating process and analyze the components manually, but this requires too much time to obtain the analysis result. However, if the number of analysis items increases, this disadvantage is promoted.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a plating apparatus for a substrate capable of automatically analyzing the composition of a plating solution at each time and promptly displaying the composition on a monitor. I do.

[0009]

A plating apparatus for a substrate according to the present invention is a plating apparatus for a substrate for plating a surface of a substrate by immersing the substrate in a plating solution, wherein the plating solution is supplied at a constant period. And automatic monitoring means for automatically analyzing the components of the sampled plating solution, and monitor display means for displaying the result of analysis by the automatic analysis means.

[0010] This makes it possible to sample the plating solution used in the plating process at a predetermined period, analyze the components automatically, and quickly display the analysis result on a monitor.

[0011] Further, an electrolytic copper plating solution is used as the plating solution, and at least one of a copper ion concentration, a sulfuric acid concentration, a chloride ion concentration, and an additive concentration is measured by the automatic analysis means. I do.

Further, an electroless copper plating solution is used as the plating solution, and at least one of a copper ion concentration, a reducing agent concentration, a pH, a chelate concentration, a dissolved oxygen, a dissolved hydrogen, and an additive concentration is determined by the automatic analysis means. It is characterized by measuring at least one.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. The plating apparatus according to this embodiment is used to obtain a semiconductor device in which copper plating is performed on a surface of a semiconductor substrate and a wiring made of a copper layer is formed. Will be explained.

[0014] That is, in the semiconductor the substrate W, as shown in FIG. 1 (a), an insulating film 2 made of SiO ₂ is deposited on a conductive layer 1a on a semiconductor substrate 1 on which the semiconductor element is formed,
A contact hole 3 and a wiring groove 4 are formed by lithography / etching technology, and a barrier layer 5 made of TiN or the like is formed thereon.

Then, as shown in FIG. 1B, the surface of the semiconductor substrate W is plated with copper to fill the contact holes 3 and the grooves 4 of the semiconductor substrate 1 with copper and to form an insulating film. A copper layer 6 is deposited on 2. Thereafter, the copper layer 6 on the insulating film 2 is formed by chemical mechanical polishing (CMP).
Is removed, and the surface of the copper layer 6 filled in the contact hole 3 and the wiring groove 4 is made substantially flush with the surface of the insulating film 2. As a result, a wiring made of the copper layer 6 is formed as shown in FIG.

Hereinafter, a plating apparatus for plating a semiconductor substrate W with copper will be described with reference to FIG. As shown in the figure,
The plating apparatus is provided with a plating tank 11 for storing a plating solution 10, and the plating tank 11 is surrounded by an overflow tank 12. A plating solution supply pipe (not shown) for continuously supplying a plating solution is provided at the bottom of the plating tank 11, and a plating solution flowing out of the plating tank 11 is collected at the bottom of the overflow tank 11 and stored in a storage tank. The plating solution discharge pipes (not shown) to be circulated are respectively connected.

A susceptor 15 for mounting and holding the substrate W is disposed inside the plating tank 11 so as to be movable up and down. The substrate W is held on the susceptor 15 and The plating process is performed by dipping in the plating solution 10 in the plating solution 11.

This plating apparatus is provided with a device for automatically analyzing and displaying the components of the plating solution shown in FIG. The plating solution 10 used for plating in the plating tank 11 is sampled into the sample circulation tank 17 at a constant cycle of, for example, every 6 hours. This is performed by connecting the pipings 13 and 14 communicating with the plating tank 11 to the plating tank 11 for a predetermined time.
The plating solution 10 is circulated in the sample circulation tank 17. A titration cell 21 is disposed in the vicinity of the sample circulation tank 17, and the sampling nozzle 20 reciprocates between the sample circulation tank 17 and the titration cell 21 to transfer the plating solution 10 in the sample circulation tank 17 to the titration cell. 2
1 is dropped.

Further, an automatic analyzing means 22 for automatically analyzing the components of the plating solution dropped into the titration cell 21 is provided. In this embodiment, the titration cell 2
The automatic analysis means 22 is constituted by the pure water line 23, the reagent A line 24, and the reagent B line 25 connected to 1, and these reagents are automatically supplied into the titration cell 21 according to a program. The components of the plating solution 10 inside this are automatically analyzed.

The titration cell 21 is connected to a cleaning liquid line 26 for supplying a cleaning liquid therein, a calibration liquid line 27 for supplying a calibration liquid, and a waste liquid line 28. As a result, the plating solution (waste solution) after the analysis is discharged from the waste solution line 28, and the cleaning and calibration in the titration cell 21 is performed with the cleaning solution and the calibration solution supplied from the cleaning solution line 26 and the calibration solution line 27.

A display 30 is provided as a monitor display means for displaying the result of the automatic analysis by the automatic analysis means 22 on a monitor. The analysis result and the pure water line 23, the reagent A line 24 and the reagent B line 25 are provided. Are sequentially displayed on the display 30. Thereby, the change of the components of the plating solution 10 is predicted in advance,
By supplying an appropriate amount of unexpected components, the plating solution can always be maintained at a normal composition.

As the plating solution, an electrolytic copper plating solution is used for electrolytic copper plating, and an electroless copper plating solution is used for electroless plating. Table 1 shows an example of the composition of the liquid.

[Table 1] Table 2 shows an example of plating conditions.

[Table 2]

In the electrolytic copper plating, the components for keeping the electrolytic copper plating solution normal, ie, copper ion concentration, sulfuric acid concentration, chloride ion concentration, additive concentration, etc. Measured, in the case of electroless copper plating, each component to keep the electroless copper plating solution normal, namely, copper ion concentration, reducing agent concentration, pH, chelate concentration,
The dissolved oxygen, dissolved hydrogen, additive concentration and the like are measured by the automatic analysis means 22 and are sequentially displayed on the display 30.

[0024]

As described above, according to the present invention,
The plating solution used in the plating process is sampled at regular intervals, the components are automatically analyzed, and the results of the analysis can be quickly displayed on the monitor.
The concentration of the composition of the plating solution or the like is checked in advance, and the plating solution can be constantly maintained at a normal composition, and the plating process can be performed stably.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a step of performing plating by a plating apparatus of the present invention.

FIG. 2 is a sectional view of a plating tank of the plating apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram showing an outline of an automatic analyzer / display device for components of a plating solution.

[Explanation of symbols]

 Reference Signs List 10 plating solution 11 plating tank 15 susceptor 17 sample circulation tank 20 sampling nozzle 21 titration cell 22 automatic analysis means 30 display (monitor display means)

Claims (3)

[Claims] 1. A plating apparatus for a substrate, wherein a substrate is immersed in a plating solution to perform plating on a surface of the substrate, wherein a sampling means for sampling the plating solution at a constant cycle; A substrate plating apparatus, comprising: automatic analysis means for automatically analyzing the components; and monitor display means for displaying an analysis result by the automatic analysis means. 2. An electrolytic copper plating solution is used as the plating solution, and the automatic analysis means uses a copper ion concentration, a sulfuric acid concentration,
The substrate plating apparatus according to claim 1, wherein at least one of a chlorine ion concentration and an additive concentration is measured. 3. An electroless copper plating solution is used as the plating solution, and the automatic analysis means uses at least one of a copper ion concentration, a reducing agent concentration, a pH, a chelate concentration, a dissolved oxygen, a dissolved hydrogen, and an additive concentration. The substrate plating apparatus according to claim 1, wherein at least one is measured.