JP7551801B2 - System for chemical and/or electrolytic surface treatment - Patents.com - Google Patents

Description

The present invention relates to a system for chemical and/or electrolytic surface treatment of a substrate in a process fluid, a device for chemical and/or electrolytic surface treatment of a substrate in a process fluid, and a method for chemical and/or electrolytic surface treatment of a substrate in a process fluid.

In the semiconductor industry, a variety of processes can be used to deposit or remove material onto or from the surface of a wafer.

For example, electrochemical deposition (ECD) or electrochemical mechanical deposition (ECMD) processes can be used to deposit conductors such as copper onto a pre-patterned wafer surface to create device interconnect structures.

Chemical mechanical polishing (CMP) is often used for the material removal step. Alternative techniques, electrolytic polishing or electrolytic etching, can also be used to remove excess material from the surface of the wafer.

Electrochemical (or electrochemical mechanical) deposition of material onto or removal of material from a wafer surface are collectively referred to as "electrochemical processing." Electrochemical, chemical and/or electrolytic process techniques can include electropolishing (or electroetching), electrochemical mechanical polishing (or electrochemical mechanical etching), electrochemical deposition and electrochemical mechanical deposition. All techniques utilize a process fluid.

Chemical and/or electrolytic surface treatment techniques involve the following steps: The substrate to be treated is mounted on a substrate holder and immersed in an electrolytic process fluid to act as a cathode. An electrode is immersed in the process fluid to act as an anode. A direct current is applied to the process fluid to dissociate positively charged metal ions at the anode. The ions then migrate to the cathode and plate the substrate attached to the cathode.

One difficulty in such processes is that air bubbles can become trapped under the wafer as it is lowered into the process solution. If the process is, for example, a deposition process for copper, such bubbles can prevent copper from depositing on the bubble-containing areas of the wafer surface, resulting in unplated or poorly plated areas that exhibit defects in the plating material. Such defects reduce the reliability of the interconnect structure. Similarly, in electropolishing processes, trapped bubbles can slow the removal of material from the bubble-containing areas, causing non-uniformity and defects that lead to reliability problems.

In this regard, US Pat. No. 6,299,333 discloses a prewetting method and system for preventing bubble formation on selected areas of a wafer surface when the surface is contacted with a process solution for an electrochemical process. During the process, the wafer surface is first brought close to the surface of the process solution. Then, a flow of the process solution is directed towards the selected area of the wafer surface for a predetermined time. In a next step, the wafer surface is immersed in the process solution for the electrochemical process, contacting the selected area of the wafer surface with the flow of the process solution for a predetermined time to prevent bubble formation.

However, such a prewetting approach is not optimal.

US Patent Application Publication No. 2004/182712

Therefore, there may be a need to provide an improved system for chemical and/or electrolytic surface treatment of a substrate in a process fluid that still allows for better and more uniform material deposition on the substrate.

The problem of the present invention is solved by the subject matter of the independent claims, further embodiments are defined in the dependent claims. It should be noted that the aspects of the present invention described below also apply to a system for chemical and/or electrolytic surface treatment of a substrate in a process fluid, a device for chemical and/or electrolytic surface treatment of a substrate in a process fluid, and a method for chemical and/or electrolytic surface treatment of a substrate in a process fluid.

According to the present invention, a system for chemical and/or electrolytic surface treatment of a substrate in a process fluid is presented.

The chemical and/or electrolytic surface treatment may be any material deposition, zinc plating coating, chemical or electrochemical etching, anodization, metal separation or the like.

The substrate may include a conductor plate, a semiconductor substrate, a film substrate, a metal or metallized workpiece essentially in the form of a flat plate, or the like. The surface to be treated may be at least partially masked or unmasked.

A system for chemical and/or electrolytic surface treatment includes a basin, a fluid passage, an expansion tank, and a control unit.

The bath is configured for chemical and/or electrolytic surface treatment of the substrate in a process fluid. In other words, the bath is a reservoir in which the substrate is treated, e.g., coated. The bath may be a vertical plating chamber into which the substrate can be inserted vertically.

The fluid passage connects the tank and the expansion tank. The fluid passage may be a connection or a pipe between the tank and the expansion tank.

The expansion tank is configured to hold an expansion volume of the process fluid. The expansion tank may be a separate reservoir located next to the tank. The expansion tank may have a smaller volume than the tank.

The control unit may be a processor. The control unit may be capable of detecting the level of the process fluid in at least one of the vessel and the expansion tank. The control unit may be capable of operating to cause the process fluid to enter or exit from at least one of the vessel and the expansion tank.

The control unit and the fluid passages may be configured to maintain the level of the process fluid in the vessel essentially constant. The term "essentially constant" may be understood as the height of the liquid process fluid in the vessel remaining at the same level regardless of external influences. The term "essentially constant" may be understood as within 15% more or less than strictly constant, preferably within 10% more or less than strictly constant, more preferably within 5% more or less than strictly constant. The control unit and the fluid passages may be configured to maintain the level of the process fluid in the vessel essentially constant. The term "essentially constant" may be understood as within 5% more or less than strictly constant. The control unit and the fluid passages may be configured to maintain the level of the process fluid in the vessel essentially constant.

The system for chemical and/or electrolytic surface treatment of a substrate in a process fluid according to the present invention makes it possible to prevent drying of parts of the device for chemical and/or electrolytic surface treatment, such as, for example, a distribution part to be placed in the bath, which can lead to harmful crystallization of particles of the process fluid. The distribution part may be a part configured to direct the flow of the process fluid and/or electric current to the substrate.

The system for chemical and/or electrolytic surface treatment according to the invention can furthermore make it possible to prevent the introduction of air into parts of the device for chemical and/or electrolytic surface treatment, such as, for example, the housing containing the distribution section and/or the anode, the anode and/or the distribution section. The introduction of air can result in harmful oxidation of particles of the process fluid and/or so-called bubble shielding of the substrate.

As a result, the system for chemical and/or electrolytic surface treatment according to the present invention allows for a uniform flow of liquid over the substrate surface, a targeted distribution of the electric field between the substrate and the counter electrode, and thereby easier and more uniform deposition of material on the substrate.

In one example, the substrate holder holds a substrate. The external influences that may change the level of the process fluid in the bath, which are prevented here, may be the introduction and/or removal of the substrate holder holding one or two substrates (one substrate on each side of the substrate holder) or the substrate holder alone. In one example, the control unit is configured to maintain the level of the process fluid essentially constant when the substrate holder is removed from the bath. In one example, the fluid passages are configured to maintain the level of the process fluid essentially constant when the substrate holder is introduced into the bath. The substrate holder may displace a volume of, for example, 20 liters, while the expansion tank may have a volume of, for example, 30 liters.

The external influences which may change the level of the process fluid in the tank, which are prevented here, may be evaporation, flashing, spillage, breakdown or the like of the process fluid.

In one example, the system further includes pumping means configured to continuously circulate the process fluid between the reservoir and the expansion tank. The pumping means may be a pump. The pumping means may permanently pump the process fluid from the reservoir to the expansion tank and vice versa.

In one example, the pumping means is configured to increase the pumping volume to balance the removal of the substrate holder. In other words, when an expansion volume must be pumped from the vessel to the expansion tank, this can be done by increasing the pumping volume per time, e.g., by increasing the motor speed. In contrast, the pumping means may be configured to move process fluid between the vessel and the expansion tank only when an expansion volume must be moved to keep the level of process fluid in the vessel essentially constant.

In one example, the fluid passage connects the overflow outlet of the tank with an expansion tank.

In one example, the control unit is configured to maintain the level of the process fluid above the top of the distribution section to be placed in the bath. The distribution section may be a component configured to direct the flow of at least one of the process fluid and the electric current to the substrate. In another example, the control unit is configured to maintain the level of the process fluid essentially at the level of the top of the distribution section to be placed in the bath. Both possibilities make it possible to prevent any damage to the distribution section due to drying, introduction of air or the like. In one example, the control unit is configured to prevent drying of the distribution section to be placed in the bath. In one example, the control unit is configured to prevent introduction of air into the distribution section to be placed in the bath.

In one example, the system further includes a temperature control system configured to detect the temperature of the process fluid and control a change in the temperature of the process fluid, e.g., by at least one of heating and cooling.

In one example, the system further includes a composition control system configured to detect a chemical property of the process fluid and control a change in the chemical property of the process fluid. The chemical property of the process fluid may be a composition, a pH value, an amount of an additive, or the like. The change in the chemical property may be made by adding some component.

According to the invention, a device for chemical and/or electrolytic surface treatment of a substrate in a process fluid is also presented. The device for chemical and/or electrolytic surface treatment includes a system for chemical and/or electrolytic surface treatment of a substrate in a process fluid as described above and a substrate holder. The substrate holder is configured to hold a substrate. The substrate holder may be configured to hold one or two substrates (one substrate on each side of the substrate holder).

According to the invention, a method for chemical and/or electrolytic surface treatment of a substrate in a process fluid is also presented. The method for chemical and/or electrolytic surface treatment comprises the following steps, not necessarily in this order:
a) conducting an expanded volume of process fluid from a bath for chemical and/or electrolytic surface treatment of a substrate to an expansion tank; and b) re-introducing the expanded volume of process fluid from the expansion tank into the bath such that the level of the process fluid in the bath is maintained essentially constant.

In one example, the method for chemical and/or electrolytic surface treatment further comprises the steps of:
- associated with step a) placing the substrate holder into the bath,
- In connection with step b), the substrate holder is removed from the bath.

The substrate holder may hold one or two substrates (one on each side of the substrate holder).

In one example, the process fluid is continuously circulated between the reservoir and the expansion tank.

In one example, the method further includes a temperature control method configured to detect the temperature of the process fluid and control a change in the temperature of the process fluid, e.g., by at least one of heating and cooling.

In one example, the method further includes a composition control method configured to detect a chemical property of the process fluid and control a change in the chemical property of the process fluid. The chemical property of the process fluid may be a composition, a pH value, an amount of an additive, or the like. The change in the chemical property may be made by adding some component.

As a result, the present invention relates to a method for realizing a locally defined liquid flow on a substantially planar substrate for the purpose of a controllable material transport over the entire surface, as well as a device for structurally realizing the method according to the invention. At the same time, the present invention provides a targeted electric field distribution on the conductive substrate surface.

The devices and methods are particularly suitable for processing structured semiconductor substrates, conductor plates and film substrates, but also for processing the entire surface of planar metal and metallized substrates. The devices and methods may also be used in accordance with the invention for the manufacture of large surface photovoltaic panels or large scale monitor panels for solar energy generation.

It will be understood that the systems, devices and methods for chemical and/or electrolytic surface treatment of a substrate in a process fluid according to the independent claims have at least one similar and identical preferred embodiment as defined in the dependent claims, among others. It will further be understood that a preferred embodiment of the invention can be any combination of the dependent claims with the respective independent claims.

These and other aspects of the invention will become apparent from and be elucidated with reference to the embodiments described hereinafter.

FIG. 1 shows a schematic and exemplary embodiment of a device for chemical and/or electrolytic surface treatment of a substrate in a process fluid according to the present invention. FIG. 2A is a schematic and exemplary diagram illustrating one embodiment of a substrate holder for holding two substrates. FIG. 1 shows a schematic and exemplary embodiment of a system for chemical and/or electrolytic surface treatment of a substrate in a process fluid according to the present invention. FIG. 1 shows a schematic and exemplary embodiment of a system for chemical and/or electrolytic surface treatment of a substrate in a process fluid according to the present invention. FIG. 1 illustrates the basic steps of an example of a method for chemical and/or electrolytic surface treatment of a substrate in a process fluid according to the present invention.

Exemplary embodiments of the present invention are described below with reference to the accompanying drawings.

1, 3 and 4 show, in a schematic and exemplary manner, one embodiment of a device 100 for chemical and/or electrolytic surface treatment of a substrate 30 in a process fluid according to the present invention. The device 100 for chemical and/or electrolytic surface treatment comprises a system 10 for chemical and/or electrolytic surface treatment of a substrate 30 in a process fluid and a substrate holder 20.

The substrate holder 20 is shown in FIG. 2 and is configured to hold a substrate 30. The substrate holder 20 here holds two substrates, one substrate 30 on each side of the substrate holder 20. The substrate holder 20 may also be configured to hold only one substrate, which may be processed from one or both sides.

The system 10 for chemical and/or electrolytic surface treatment of a substrate 30 in a process fluid as shown in Figures 1, 3 and 4 generates a target flow and current density pattern for chemical and/or electrolytic surface treatment. The system 10 includes two distribution sections 21 submerged in the process fluid (not shown). Opposite each distribution section 21 is a substrate 30 mounted on a substrate holder 20. The surface of the substrate 30 is wetted by the process fluid. There are two electrodes, here two anodes 22, each located on the opposite side of the distribution section 21 from the substrate 30 and also immersed in the process fluid.

The distribution section 21 has at least one inlet opening 23 for the process fluid and at least one liquid passage terminating in an array of outlet nozzles (not shown) at the front face of the distribution section 21. The pumped process fluid flows through the outlet nozzles at relatively high velocities towards the substrate 30 to carry out the desired chemical and/or electrolytic reactions at that location.

The substrate 30 may be a basically flat-shaped workpiece for the manufacture of electrical or electronic components and is mechanically fixed to the substrate holder 20. As the treatment medium leaves the distribution section 21, the surface of the substrate 30 to be treated is immersed in the process fluid. In special cases, the substrate 30 may be a masked or unmasked conductor plate, a semiconductor substrate or a film substrate, or any metal or metallized workpiece with a substantially planar surface.

The distribution part may preferably consist of plastic, particularly preferably polypropylene, polyvinyl chloride, polyethylene, acrylic glass, i.e. polymethyl methacrylate, polytetrafluoroethylene, or another material which is not degraded by the process solution.

The anode 22 is attached to the rear region of the distribution part 21, either in mechanical contact with it or spatially separated from it, so that a current flow occurs between the anode 22 and the substrate 30, which acts as a counter electrode in the process fluid. Depending on the surface treatment method used, the anode 22 may consist of a material that is insoluble in the process liquid, such as platinum-coated titanium, or in other circumstances, a soluble material, for example a metal that is to be galvanically separated.

Figures 3 and 4 are schematic and exemplary diagrams illustrating one embodiment of a system 10 for chemical and/or electrolytic surface treatment of a substrate 30 in a process fluid according to the present invention. The system 10 for chemical and/or electrolytic surface treatment includes a tank 11, a fluid passage 12, an expansion tank 13, and a control unit 14. A substrate holder 20 with a substrate 30 is placed in the tank 11 in Figure 3 and outside the tank 11 in Figure 4.

The bath 11 is configured for chemical and/or electrolytic surface treatment of the substrate 30 in a process fluid to form a reservoir in which the substrate 30 is treated. The bath 11 is a vertical plating chamber into which the substrate 30 (not shown) is vertically loaded.

The fluid passage 12 connects the tank 11 and the expansion tank 13 in the form of a pipe between the tank 11 and the expansion tank 13.

The expansion tank 13 holds the expansion volume of the process fluid and is located next to the tank 11. The expansion tank 13 has a smaller volume than the tank 11.

The control unit 14 is here a processor. The control unit 14 detects the level of the process fluid in the tank 11 and operates the process fluid to enter or leave at least one of the tank 11 and the expansion tank 13. The control unit 14 can therefore control the pumping means 15.

The control unit 14 and the fluid passages 12 maintain the level of the process fluid in the vessel 11 essentially constant. The term "essentially constant" may be understood as meaning that the height of the liquid process fluid in the vessel 11 remains at the same level regardless of external influences.

The control unit 14 maintains the level of the process fluid essentially constant when the substrate holder 20 without or with one or two substrates 30 is removed from the tank 11 (FIG. 4) and when the substrate holder 20 is inserted into the tank 11 (FIG. 3). The level L of the process fluid in the expansion tank 13 therefore decreases from FIG. 3 to FIG. 4.

The system 10 further includes pumping means 15 for continuously circulating the process fluid between the vessel 11 and the expansion tank 13, i.e. from the vessel 11 to the expansion tank 13 and vice versa. The pumping means 15 may increase the pumping volume to balance the removal of the substrate holder 20.

The fluid passage 12 connects the overflow outlet 16 of the tank 11 to the expansion tank 13.

The control unit 14 maintains the level of the process fluid above the top of the distribution section 21 disposed in the vessel 11. The control unit 14 may maintain the level of the process fluid essentially at the level of the top of the distribution section 21 disposed in the vessel 11. Either option may prevent any damage to the distribution section 21 due to drying, introduction of air or the like. Thereby, the control unit 14 prevents drying of the distribution section 21 in the vessel 11. Furthermore, the control unit 14 prevents the introduction of air into the distribution section 21.

The system 10 further includes a temperature control system 17 for detecting the temperature of the process fluid and controlling a change in the temperature of the process fluid, e.g., by at least one of heating and cooling.

The system 10 further includes a composition control system 18 for detecting a chemical property of the process fluid and controlling a change in the chemical property of the process fluid. The chemical property of the process fluid may be a composition, a pH value, an amount of an additive, or the like. The change in the chemical property may be made by adding some component.

The system 10 for chemical and/or electrolytic surface treatment of a substrate 30 in a process fluid according to the invention makes it possible to prevent drying out of the parts of the device 100 for chemical and/or electrolytic surface treatment. The system 10 can further make it possible to prevent the introduction of air into the parts of the device 100 for chemical and/or electrolytic surface treatment. As a result, the system 10 for chemical and/or electrolytic surface treatment according to the invention makes it possible to achieve a uniform flow of liquid on the substrate surface, a targeted distribution of the electric field between the substrate 30 and the counter electrode, and thereby an easier and more uniform material deposition on the substrate 30.

5 shows a schematic diagram of the method steps for chemical and/or electrolytic surface treatment of a substrate 30 in a process fluid. The method for chemical and/or electrolytic surface treatment comprises the following steps:
In a first step S1, an expansion volume of process fluid is conducted from a bath 11 for chemical and/or electrolytic surface treatment of a substrate 30 into an expansion tank 13.

- In a second step S2, the expanded volume of process fluid is recharged from the expansion tank 13 to the tank 11 so that the level of the process fluid in the tank 11 remains essentially constant.

The method for chemical and/or electrolytic surface treatment further includes placing the substrate holder 20 into the bath 11 in association with step S1 and removing the substrate holder 20 from the bath 11 in association with step S2.

The substrate holder 20 may hold one or two substrates (one substrate 30 on each side of the substrate holder 20 shown in FIG. 2).

It should be noted that embodiments of the present invention are described with reference to different subject matters. In particular, some embodiments are described with reference to method claims, whereas other embodiments are described with reference to apparatus claims. However, one skilled in the art will appreciate from the above and following description that, unless otherwise indicated, any combination of features belonging to one subject matter, as well as any combination between features relating to different subject matters, may be made, which are considered to be disclosed by this application. However, all features may be combined to provide synergistic effects beyond the mere sum of the features.

While the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Those skilled in the art of the claimed invention can understand and produce other variations to the disclosed embodiments, from a study of the drawings, the disclosure and the dependent claims.

In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several components recited in the claims. The mere fact that certain means are recited in mutually different dependent claims does not indicate that a combination of these means cannot be used to advantage. Any reference signs in the claims should not be interpreted as limiting the scope.

REFERENCE SIGNS LIST 10 System 11 Tank 12 Fluid passage 13 Expansion tank 15 Pumping means 16 Overflow outlet 17 Temperature control system 18 Composition control system 20 Substrate holder 30 Substrate 100 Device

Claims (16)

A system (10) for chemical and/or electrolytic surface treatment of a substrate (30) in a process fluid, comprising:
A tank (11),
A fluid passage (12);
An expansion tank (13);
A control unit (14),
the bath (11) is configured for the chemical and/or electrolytic surface treatment of the substrate (30) in the process fluid;
The fluid passage (12) connects the tank (11) and the expansion tank (13),
The expansion tank (13) is configured to hold an expansion volume of the process fluid;
the control unit (14) and the fluid passage (12) are configured to maintain the level of the process fluid in the vessel (11) within 15% more or less than strictly constant;
the control unit (14) is configured to prevent drying of a distribution portion (21) to be placed in the bath (11);
The distribution section (21) is configured to direct the flow of at least one of the process fluid and the electric current to the substrate (30).
System (10). The system (10) of claim 1 further comprising a pumping means (15) configured to continuously circulate the process fluid between the tank (11) and the expansion tank (13). The system (10) of any one of claims 1 to 2, wherein the control unit (14) is configured to maintain the level of the process fluid within a range of 15% more or less than strictly constant when the substrate holder (20) is removed from the bath (11). The system (10) of claim 2 , wherein the pumping means (15) is configured to increase the pumping volume to balance the removal of the substrate holder (20). 2. The system (10) of claim 1 , wherein the fluid passage (12) is configured to maintain the level of the process fluid within a range of more or less than 15% of a strictly constant level when a substrate holder (20) is inserted into the bath ( 11 ). The system (10) of claim 1 , wherein the fluid passage (12) connects an overflow outlet (16) of the reservoir (11) with the expansion tank (13). The system (10) of claim 3 , wherein the substrate holder (20) holds the substrate (30). 2. The system (10) of claim 1, wherein the control unit (14) is configured to maintain the level of the process fluid above a top of the distribution section (21) to be disposed in the tank (11). 2. The system (10) of claim 1, wherein the control unit (14) is configured to maintain the level of the process fluid at the level of a top of the distribution section (21) to be disposed in the tank (11). The system (10) of claim 1 , further comprising a temperature control system (17) configured to sense a temperature of the process fluid and control a change in the temperature of the process fluid. The system (10) of claim 1 , further comprising a composition control system (18) configured to sense a chemical property of the process fluid and control a change in the chemical property of the process fluid. 2. The system (10) of claim 1, wherein the control unit (14) is configured to prevent the introduction of air into at least one of the distribution section (21) and the anode ( 22 ) to be disposed in the tank (11). A device (100) for chemical and/or electrolytic surface treatment of a substrate (30) in a process fluid, comprising:
A system (10) according to claim 1 ,
A substrate holder (20);
The substrate holder (20) is configured to hold the substrate (30).
Device (100). 1. A method for chemical and/or electrolytic surface treatment of a substrate (30) in a process fluid, comprising the steps of:
a) directing an expansion volume of said process fluid from a bath (11) for chemical and/or electrolytic surface treatment of said substrate (30) to an expansion tank (13);
Step b) of recharging the expanded volume of the process fluid from the expansion tank (13) into the tank (11) so that the level of the process fluid in the tank (11) is kept strictly constant within a range of 15% more or less; and preventing drying of the distribution part (21) that will be placed in the tank (11),
The method of claim 1, wherein the distribution section (21) is configured to direct a flow of at least one of the process fluid and the electric current to the substrate (30). In step a, a substrate holder (20) is placed in the bath (11);
The method of claim 14, further comprising the step of: removing the substrate holder (20) from the bath (11) in step b. The method according to claim 14 or 15, wherein the process fluid is continuously circulated between the tank (11) and the expansion tank (13).

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