JP2006009051A - Method for washing substrate subjected to plating treatment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method capable of washing away a plating solution stuck to the back face of a wafer immediately after plating treatment by a simple structure in a mass-production line including a face up type plating apparatus. <P>SOLUTION: In the mass-production line including a face up type plating apparatus 3, a nozzle 21 for cleaning the back face of a wafer is arranged below a moving space in a robot 2 for taking out a wafer from the upper face of a wafer holder 4 at the lower part of the plating apparatus 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cleaning for cleaning a substrate plated by the plating apparatus in a mass production line including a plating apparatus for performing electrolytic plating on a substrate such as various electronic component substrates, IC wafers, and thin film magnetic head wafers. More particularly, the present invention relates to a method for cleaning the back surface of a substrate.

  FIG. 4 shows a schematic plan view of a mass production line including a plating apparatus for forming a plating film on the substrate as described above. With reference to this figure, the process of plating the substrate to be processed will be described.

  A wafer as a plurality of substrates to be processed is mounted on the loader 1, and the robot 2 takes out an unprocessed wafer from the loader 1. The robot 2 carries the wafer to the lower part of the face-up type plating apparatus 3 which will be described in detail later, and places it on the upper surface of the wafer holder 4 waiting there. The wafer rises together with the wafer holder 4 and is brought into close contact with the plating apparatus 3 so as to close the opening at the bottom of the plating apparatus 3 with the wafer (see FIG. 5). In this state, the wafer surface is plated.

  When the plating process is completed, the wafer holder 4 is lowered to the original position. The robot 2 picks up the plated wafer from the wafer holder 4 and moves it to the end of the transfer belt 5. The wafer placed on the transport belt 5 first passes through the inside of the cleaning device 6. Here, impurities on the wafer surface are completely washed away by spraying a cleaning liquid such as pure water from above the wafer like a shower.

  After cleaning, the wafer moves in the drying device 7. Here, the wafer surface is dried by blowing air or the like, and moisture on the back surface of the wafer is wiped off by a moisture absorption roller.

  After drying, the wafer is stored in the unloader 8 with a space from the wafer stored in front of the wafer.

  Next, the plating apparatus 3 will be described with reference to FIGS. 5 and 6.

  The plating apparatus 3 is an apparatus called a face-up type. As shown in FIGS. 5 and 6, in this plating apparatus, the wafer 13 held on the wafer holder 14 is moved to the plating tank 11 while the wafer holder 14 is raised. The lower opening 11 a is closed and the cathode 12 is electrically contacted. A plating solution 17 is supplied to the plating tank 11 and can be supplied and discharged from a supply port 18 and a discharge port 19 below the plating tank 11. An anode 15 is disposed opposite the cathode 12 in the plating tank 11.

  In this state, the direct current power supply 16 is operated to pass a current between the anode 15 and the cathode 12, whereby electrolytic plating is performed on the surface of the wafer 13 electrically connected to the cathode 12.

  After the completion of the plating process, the DC power supply 16 is stopped, and the plating solution 17 in the plating tank 11 is discharged from the discharge port 19. While the plating solution 17 in the plating tank 11 is discharged, a weak current is supplied to the plating solution 17 by the auxiliary power source 21 so that the surface of the wafer 13 on which the plating film is applied is not etched by the plating solution 17.

  After the plating solution is discharged, the wafer holder 14 is lowered to a predetermined position, and the wafer 13 on which the plating film is formed is removed from the wafer holder 14.

  In such a face-up type plating apparatus, the wafer holder 14 descends below the plating apparatus and the wafer 13 is removed by the robot 2 as shown in FIG. The plating solution adhering to the surface of the wafer 13 is washed away by spraying the cleaning solution.

  The surface of the wafer 13 is cleaned as described above, when the plating solution remains on the plating surface of the wafer 13, the plating film is generally dissolved with a plating solution that is a strong acid, and the film thickness is increased. This is because unevenness occurs.

  In addition, there exists a thing of patent document 1, 2 as an example of the washing | cleaning method of to-be-plated object.

  In the invention disclosed in Patent Document 1, while holding the wafer, a cleaning liquid is sprayed onto each of the surface of the wafer on which the predetermined processing is performed and the surface on the opposite side. The front and back surfaces are cleaned.

  In the invention disclosed in Patent Document 2, a plurality of nozzles for cleaning the edge and the back surface of the wafer are disposed on the peripheral portion of the wafer whose center of the back surface is held by the holding mechanism.

Each of the inventions described in Patent Documents 1 and 2 is a method of cleaning while a wafer is held in a predetermined position.
JP 2000-331975 A (see FIG. 1) JP 2001-89898 A (see FIGS. 1 and 2)

  As described above, the face-up type plating apparatus employs a method of placing a wafer on the surface of a wafer holder and applying a plating film on the surface of the wafer. For this reason, the plating solution may enter the gap between the back surface of the wafer and the front surface of the wafer holder. When the plating solution enters in this way, when the wafer is removed from the wafer holder, the plating solution is attached to the back surface of the wafer. Furthermore, the plating solution dries and becomes crystal grains over time.

  If the wafer is moved onto the transport belt by the robot in such a state, the transport belt is contaminated with the plating solution or the crystal grains. Also, when moisture on the back surface of the wafer is removed by the moisture absorption roller of the drying device, the moisture absorption roller is contaminated if the plating solution or the crystal grains remain attached to the wafer back surface.

  Therefore, every time the plated wafer moves onto the conveyor belt and passes through the drying device, the plating solution or the crystal grains attached to the conveyor belt and the absorption roller are repeatedly adhered to the back surface of the wafer. Further, if the crystal grains of the plating solution adhere to the back surface of the wafer and are stored in the unloader, the crystal grains of the plating solution may fall on the wafer surface stored below the wafer.

  In the technical field of the present invention, the plating film tends to become thinner as the semiconductor wiring pattern becomes finer. For this reason, if the crystal grains of the plating solution fall and adhere to the wafer surface as described above, it leads to a defect in the product.

  Therefore, for the mass production line including the face-up type plating apparatus described above, the cleaning liquid is sprayed on the back surface of the wafer when the wafer is held on the wafer holder as in the inventions described in Patent Document 1 and Patent Document 2. And a method for preventing the plating solution from entering the back surface of the wafer. However, these methods complicate the structure of the wafer holder.

  In addition, the wafer backside as well as the front surface of the wafer when the wafer passes through the cleaning apparatus shown in FIG. 4 was studied. However, since the cleaning liquid is sprayed from both the front side and the back side of the wafer, There is a risk that the contained cleaning liquid will rise in the form of a mist and adhere to the wafer surface. Further, since the wafer back surface is not cleaned immediately after the plating process, the problem that the conveyor belt is contaminated with the plating solution attached to the wafer back surface cannot be solved.

  An object of the present invention is to provide a cleaning method that can wash away the plating solution adhering to the wafer back surface immediately after the plating process with a simple structure in a mass production line including a face-up type plating apparatus in view of the above-described actual situation. It is in.

  In order to achieve the above object, the present invention provides a cleaning method in which a cleaning liquid is sprayed on the back surface of a substrate to be processed in the process of moving the substrate to be processed from a holder that supports the back surface of the substrate to be processed that is plated. Provide a method.

  In this cleaning method, the back surface of the substrate to be processed is cleaned by horizontally moving the substrate to be processed across the cleaning liquid sprayed upward.

  In addition, the cleaning method includes a plating tank having an opening on the bottom surface, and a substrate holder that supports the back surface of the substrate to be processed and is movable so as to close the opening with the substrate to be processed. It is suitable for cleaning the back surface of the substrate to be processed whose surface is plated by a face-up type plating apparatus.

  According to the present invention, in the process of moving the substrate to be processed from the holder that supports the back surface of the substrate to be processed whose surface is plated, the cleaning liquid is sprayed onto the back surface of the substrate to be processed. The back surface of the substrate to be processed can be cleaned immediately thereafter, and the influence of the plating solution adhering to the back surface on the plating film can be minimized.

  Next, an embodiment of the present invention will be described. The present invention is a method of cleaning the back surface of a substrate to be processed immediately after plating in a mass production line including a face-up type plating apparatus.

  Since the detailed configuration of the face-up type plating apparatus and the mass production line including the face-up plating apparatus has already been described with reference to FIGS. 4 to 6 in the background art section, the differences from the background art are mainly omitted here.

  FIG. 1 is a plan view schematically showing a mass production line including a face-up type plating apparatus to which a cleaning nozzle according to an embodiment of the present invention is applied, and FIG. 2 is a perspective view showing an example of the cleaning nozzle of FIG. .

  In the mass production line shown in FIG. 1, a cleaning nozzle 21 is disposed under the moving space of the robot 2 that takes out the wafer from the upper surface of the wafer holder 4 below the plating apparatus 3.

  As shown in FIG. 2, the cleaning nozzle 21 has a direction in which the cleaning liquid is sprayed upward. A plurality of injection holes are provided, and are arranged in a direction orthogonal to the direction in which the robot 2 moves relative to the wafer holder 4 (the arrow direction in FIG. 2). This is a so-called slit type shower nozzle, but the present invention is not limited to this, and for example, a flat spray type in which the cross section of the injection hole has a single-letter shape may be used. In other words, any type of nozzle may be used as long as the entire back surface of the wafer can be cleaned uniformly.

  Next, with reference to FIG. 3, a cleaning process of the wafer back surface by the cleaning nozzle 21 will be described. FIG. 3 shows how the back surface of the wafer is cleaned by the cleaning nozzle 21. As shown in this figure, the wafer 13 is placed on the upper surface of the wafer holder 4 (FIG. 1A). A cleaning nozzle 21 is disposed below a moving space of a robot (not shown) that conveys the wafer 13, and a cleaning liquid is sprayed upward toward the moving space.

  The wafer 13 is picked by the robot and horizontally moved in a predetermined direction (FIGS. (B) and (c)). At this time, since the cleaning nozzle 21 below the moving space of the robot ejects the cleaning liquid upward, the wafer 13 crosses the cleaning liquid and the cleaning liquid is supplied to the back surface of the wafer 13. Since the wafer 13 is being moved by the robot, the cleaning liquid hits the back of the wafer 13 from end to end with this movement. As a result, the entire back surface of the wafer is cleaned with the cleaning liquid.

  As described above, the cleaning of the back surface of the wafer is performed in the process of removing the wafer after the plating process from the wafer holder, so that the plating solution adhering to the back surface of the wafer can be washed away immediately after the plating process.

  Thereafter, in the mass production line shown in FIG. 1, the wafer whose back surface was cleaned was transferred to the end of the transfer belt 5, passed through the cleaning device 6 and the drying device 7, and previously stored in the unloader 8. The wafer is stored at a desired space.

  As described above, since the back surface of the wafer is cleaned immediately after the plating process, the transport belt 5 and the moisture absorption roller in the drying device 7 are not contaminated by the plating solution or the crystal grains. Then, the plated wafer can be stored in the unloader through the uncontaminated transport belt 5 and the moisture absorption roller. As a result, the wafer having the plating solution crystal grains attached to the back surface is not stored in the unloader. That is, there is no problem that the crystal grains of the plating solution fall on the surface of the wafer stacked with a space in the unloader, and the plating quality on the wafer surface is not impaired.

It is the top view which showed typically the mass production line containing the face-up type plating apparatus to which the washing nozzle by embodiment of this invention is applied. It is a perspective view which shows a mode that the wafer surface is wash | cleaned with the washing | cleaning nozzle of embodiment of this invention. It is the figure which showed a mode that the wafer back surface was wash | cleaned by the washing | cleaning nozzle of FIG. It is the top view which showed typically the conventional example of the mass production line containing the plating apparatus of a face-up system. It is typical sectional drawing for demonstrating the structure of the plating apparatus of FIG. It is typical sectional drawing for demonstrating the structure of the plating apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Loader 2 Robot 3 Plating apparatus 4 Wafer holder 5 Conveyor belt 6 Cleaning device 7 Drying device 8 Unloader 21 Cleaning nozzle

Claims (3)

  A cleaning method in which a cleaning liquid is sprayed onto the back surface of the substrate to be processed in the process of moving the substrate to be processed from a holder that supports the back surface of the substrate to be processed that is plated.   The cleaning method according to claim 1, wherein the back surface of the substrate to be processed is cleaned by horizontally moving the substrate to be processed across the cleaning liquid sprayed upward.   Surface by a face-up plating apparatus having a plating tank having an opening on the bottom surface and a substrate holder that supports the back surface of the substrate to be processed and is movable so as to close the opening with the substrate to be processed. The cleaning method according to claim 1 or 2, wherein the back surface of the substrate to be processed is cleaned.

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