JP3771440B2 - Bevel etching equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bevel etching apparatus for performing a so-called bevel etching process on various substrates such as a semiconductor wafer, a glass substrate for a liquid crystal display device, a glass substrate for a plasma display panel, and a magnetic / optical disk substrate.
[0002]
[Background]
In the manufacturing process of a semiconductor device, after forming a metal thin film such as a copper thin film on the entire surface of the front surface, back surface and end surface of a semiconductor wafer (hereinafter simply referred to as “wafer”), unnecessary portions of the metal thin film are removed by etching. Processing may be performed. For example, since the copper thin film for forming the wiring only needs to be formed in the element formation region on the front surface of the wafer, the peripheral portion of the front surface of the wafer (for example, a portion having a width of about 5 mm from the peripheral edge of the wafer), the back surface and the end surface The copper thin film formed in (1) becomes unnecessary.
[0003]
As an apparatus (bevel etching apparatus) for removing the metal thin film formed on the peripheral portion of the wafer, for example, the wafer is held by a spin chuck and rotated around the vertical axis while being applied to the upper surface of the wafer. A configuration has been proposed in which a chemical solution (etching solution) is supplied to the peripheral portion of the wafer while pure water is supplied. Even if the chemical solution splashes near the center of the wafer due to the supply of pure water, the chemical solution is quickly washed away. Therefore, the peripheral metal thin film can be selectively removed without damaging the metal thin film near the center of the wafer.
[0004]
The width of the processing region (the region where the metal thin film is removed by the chemical solution) at the peripheral edge of the wafer is determined by, for example, the flow rate of pure water supplied to the wafer. Therefore, a flow rate adjusting air valve for adjusting the flow rate of pure water is interposed in the middle of the pure water piping through which pure water to be supplied to the wafer flows. By adjusting, the width of the processing region at the peripheral edge of the wafer can be controlled.
[0005]
[Problems to be solved by the invention]
However, even if the opening degree of the flow rate adjustment air valve is adjusted so that the width of the processing region at the peripheral edge of the wafer becomes a desired width, the pressure in the pure water pipe is caused by the pulsation of pure water in the pure water pipe. As the pressure fluctuates, the flow rate of pure water supplied to the wafer may fluctuate. Therefore, the conventional bevel etching apparatus cannot satisfy the accuracy required by the user (for example, the width of 5 mm ± 0.5 mm from the peripheral edge of the wafer).
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a bevel etching apparatus that solves the above technical problem and can accurately perform an etching process on a peripheral edge portion of a substrate.
[0007]
[Means for Solving the Problems and Effects of the Invention]
In order to achieve the above object, the invention according to claim 1 is a bevel etching apparatus for selectively performing an etching process on the peripheral portion of the upper surface of the substrate (W), and holds the substrate substantially horizontally. The substrate holding and rotating means (1) for rotating while rotating, the etching solution supplying means (4, 41, 42) for supplying the etching solution to the peripheral edge of the upper surface of the substrate rotated by the substrate holding and rotating means, and the substrate holding A surface-protecting pure water nozzle (5) for supplying pure water for protecting the region other than the peripheral portion of the substrate upper surface from the etching solution toward the upper surface of the substrate rotated by the rotating means, and the surface protecting pure water A pure water pipe (51) through which pure water supplied from the water nozzle to the upper surface of the substrate circulates, and is interposed in the middle of the pure water pipe to reduce the downstream pressure in the pure water circulation direction in the pure water pipe. To keep it almost constant Look including a dynamic pressure regulating valve (6), the automatic pressure regulating valve, an inlet chamber which pure water flows (631), outflow chamber which pure water flows out (632), the inflow chamber and the outflow chamber When the flow rate or pressure of pure water flowing into the inflow chamber increases, the communication passage (633) communicating with the communication passage and the valve body (62) inserted through the communication passage increase from the inflow chamber to the communication passage. When the valve body moves so as to reduce the flow rate of pure water flowing into the outflow chamber through the flow rate, and when the flow rate or pressure of pure water flowing into the inflow chamber decreases, the outflow chamber passes through the communication passage. The bevel etching apparatus is characterized in that fluctuation of the pressure of pure water flowing out from the outflow chamber is suppressed by moving the valve body so that the flow rate of pure water flowing into the chamber increases .
[0008]
In addition, the alphanumeric characters in parentheses represent corresponding components in the embodiments described later. Hereinafter, this is the same in this section.
According to the present invention, the pressure in the pure water pipe at the downstream side in the pure water flow direction from the automatic pressure regulating valve is kept constant by the function of the automatic pressure regulating valve. Therefore, it is possible to suppress the fluctuation of the flow rate of pure water discharged from the surface-protecting pure water nozzle due to pulsation, and the processing region (the region other than the region protected by pure water, the etching solution) on the periphery of the upper surface of the substrate. The width of the region to be processed can always be maintained at a desired width. Therefore, the etching process can be accurately performed on the peripheral edge of the substrate.
[0009]
In addition, as described in claim 2, a flow rate adjustment valve (in the middle of the pure water pipe) for adjusting the flow rate of pure water supplied from the surface protecting pure water nozzle to the upper surface of the substrate. 52), and the automatic pressure regulating valve is preferably interposed upstream of the flow rate regulating valve in the pure water flow direction. By doing so, the flow rate of pure water supplied to the flow rate adjustment valve can be kept constant, so that the flow rate can be adjusted satisfactorily by the flow rate adjustment valve. The width can be set with higher accuracy.
According to a third aspect of the present invention, the automatic pressure regulating valve includes a first and a second diaphragm (64, 65) and the first diaphragm (64) sandwiched between the inflow chamber and a constant pressure. A setting air for setting the position of the valve body in a steady state is adjacent to the outflow chamber with the first air chamber (66) filled with air and the second diaphragm (65) interposed therebetween. The bevel etching according to claim 1 or 2, further comprising a second air chamber (67) to be supplied, wherein both ends of the valve body are bonded to the first and second diaphragms. Device.
According to this invention, the position of the valve body in the steady state can be set by adjusting the pressure of the setting air supplied to the second air chamber.
4. The bevel etching apparatus according to claim 3, further comprising a precision pressure reducing valve (72) for adjusting the pressure of the setting air supplied to the second air chamber. It is.
According to the present invention, the pressure of the setting air supplied to the second air chamber can be adjusted with high accuracy, and the flow rate of pure water supplied from the automatic pressure control valve to the surface protection pure water nozzle can be accurately adjusted. It can be set well.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic sectional view showing the structure of a bevel etching apparatus according to an embodiment of the present invention. This bevel etching apparatus performs a bevel etching process for removing an unnecessary thin film on the periphery of the wafer W on a wafer W that is a substrate to be processed.
[0011]
This bevel etching apparatus includes a spin chuck 1 as a substrate holding and rotating means. The spin chuck 1 includes a rotary shaft 12 rotated by a rotary drive mechanism 11 including a motor and the like, a chuck base 13 extending in a substantially horizontal direction from the upper end of the rotary shaft 12, and a plurality of standing on the chuck base 13. Each chuck 14. The chuck 14 is in contact with the peripheral edge of the wafer W and can hold the wafer W in a horizontal state. With this configuration, the rotation shaft 12 is rotated by the rotary drive mechanism 11 while the wafer W is held by the chuck 14, thereby causing the wafer W to move around a substantially vertical rotation axis passing through the center thereof in a substantially horizontal plane. Can be rotated.
[0012]
The spin chuck 1 is accommodated in a processing cup 2 disposed so as to surround the periphery of the spin chuck 1. Above the processing cup 2, a splash guard 3 that is formed in a substantially cylindrical shape is provided. The splash guard 3 is configured to be movable up and down with respect to the processing cup 2. When performing processing on the wafer W, the splash guard 3 is disposed above as shown in FIG. When attaching or detaching, the wafer W is moved downward so as not to obstruct the transfer of the wafer W.
[0013]
Above the splash guard 3, the etching liquid supply nozzle 4 for supplying the etching liquid to the upper surface of the wafer W held by the spin chuck 1 through the opening on the upper surface of the splash guard 3 and the spin chuck 1 A pure water supply nozzle 5 for supplying pure water to the upper surface of the wafer W is disposed. The etchant supply nozzle 4 is arranged to discharge the etchant toward the peripheral edge of the upper surface of the wafer W. On the other hand, the pure water supply nozzle 5 is disposed so as to discharge pure water toward the center of the upper surface of the wafer W.
[0014]
When the bevel etching process is performed on the wafer W, the rotation driving mechanism 11 is operated to rotate the wafer W held on the spin chuck 1 at a predetermined speed. Meanwhile, pure water is supplied from the pure water supply nozzle 5 toward the center of the upper surface of the wafer W, and etching liquid is supplied from the etching liquid supply nozzle 4 toward the peripheral edge of the upper surface of the wafer W. . Since the centrifugal force due to the rotation of the wafer W acts on the pure water supplied to the upper surface of the wafer W, a water flow from the center of the wafer W toward the outside is formed on the upper surface of the wafer W. Therefore, at the peripheral edge of the upper surface of the wafer W, the etching solution supplied from the etching solution supply nozzle 4 reaches the surface of the wafer W, and the unnecessary thin film formed on the surface of the wafer W is removed by this etching solution. On the other hand, even if splash of the etching solution reaches the central portion of the upper surface of the wafer W, the etching solution is quickly washed away by the flow of pure water, so that the etching solution does not damage the thin film.
[0015]
An etchant pipe 41 is connected to the etchant supply nozzle 4, and the etchant is supplied through the etchant pipe 41. An etching solution flow rate adjustment valve 42 for adjusting the flow rate of the etching solution in the etching solution pipe 41 is interposed in the middle of the etching solution pipe 41. By adjusting the opening of the etching liquid flow rate adjusting valve 42, the etching liquid can be supplied to the wafer W from the etching liquid supply nozzle 4, or the supply of the etching liquid can be stopped.
[0016]
A pure water pipe 51 is connected to the pure water supply nozzle 5, and pure water is supplied through the pure water pipe 51. A pure water flow rate adjustment valve 52 for adjusting the flow rate of pure water in the pure water pipe 51 is interposed in the middle of the pure water pipe 51. By adjusting the opening of the pure water flow rate adjustment valve 52, pure water can be supplied from the pure water supply nozzle 5 to the wafer W, or the supply of the pure water can be stopped. Further, by adjusting the opening of the pure water flow rate adjusting valve 52 and adjusting the flow rate of pure water supplied from the pure water supply nozzle 5 to the wafer W, the flow of water formed by the pure water on the upper surface of the wafer W is adjusted. The strength can be controlled, and the width of the processing region (region subjected to processing with the etching solution) at the peripheral edge of the upper surface of the wafer W can be controlled.
[0017]
Even if the opening degree of the pure water flow rate adjustment valve 52 is adjusted so that the width of the processing region at the peripheral edge of the upper surface of the wafer W becomes a desired width (for example, 5 mm from the peripheral edge of the wafer W), the pure water pipe 51 Due to the pulsation of pure water flowing inside, the pressure in the pure water pipe 51 fluctuates, and the flow rate of pure water discharged from the pure water supply nozzle 5 may fluctuate with this pressure fluctuation. Therefore, in this embodiment, the pressure of the pure water supplied to the pure water flow rate adjustment valve 52 in the middle of the pure water pipe 51 and upstream of the pure water flow rate adjustment valve 52 with respect to the flow direction of the pure water. An automatic pressure regulating valve 6 is provided for keeping the pressure constant.
[0018]
As shown in FIG. 2, the automatic pressure regulating valve 6 includes a valve main body 61 and a valve body 62 accommodated in the valve main body 61.
In the valve main body 61, a valve chamber 63 for accommodating the valve body 62 and air chambers 66 and 67 partitioned from the valve chamber 63 by diaphragms 64 and 65 are formed. The valve chamber 63 includes an inflow chamber 631 adjacent to the air chamber 66 with the diaphragm 64 interposed therebetween, an outflow chamber 632 adjacent to the air chamber 67 with the diaphragm 65 interposed therebetween, and a communication path 633 communicating the inflow chamber 631 and the outflow chamber 632. It consists of and. The communication path 633 is formed so as to penetrate the block 68 that separates the inflow chamber 631 and the outflow chamber 632.
[0019]
The valve body 62 includes a small diameter portion 621 accommodated in the inflow chamber 631, a large diameter portion 622 accommodated in the outflow chamber 632, and a connecting portion 623 that connects the small diameter portion 621 and the large diameter portion 622. ing. The small diameter portion 621 is bonded to the diaphragm 64, and the large diameter portion 622 is bonded to the diaphragm 65. Further, the connecting portion 623 is inserted into the communication path 633. The inflow chamber 631 communicates with an inlet 634 to which pure water is supplied from a pure water supply source (not shown), and the pure water that has flowed from the inlet 634 into the inflow chamber 631 flows into the inflow chambers of the small diameter portion 621 and the block 68. It flows into the outflow chamber 632 through the space between the communication path 633 and the connection portion 623 through the space between the surface facing 631 and the connection portion 623. And it flows out from this outflow chamber 632 toward the pure water flow rate adjustment valve 52 (see FIG. 1) through the outlet 635.
[0020]
Since the small diameter portion 621 is bonded to the diaphragm 64 and the large diameter portion 622 is bonded to the diaphragm 65, the valve body 62 moves up and down by the deformation of the diaphragms 64 and 65. The position of the valve body 62 in the steady state can be set by adjusting the pressure of the setting air supplied to the air chamber 67. The air chamber 66 is filled with air of a certain pressure, and the pressure in the air chamber 66 is not changed. The distance between the small diameter portion 621 and the surface of the block 68 facing the inflow chamber 631 is determined depending on the position of the valve body 62, whereby the flow rate of pure water flowing into the outflow chamber 632 from the inflow chamber 631 through the communication path 633. Therefore, the pressure of the setting air supplied to the air chamber 67 is set according to the flow rate of pure water discharged from the pure water supply nozzle 5 (see FIG. 1).
[0021]
For example, when the flow rate or pressure of pure water flowing into the inflow chamber 631 increases, the pressure of pure water flowing from the inflow chamber 631 through the communication path 633 into the outflow chamber 632 increases, and the large-diameter portion 622 of the valve body 62 is increased. Receives a force in the direction of pushing the diaphragm 65 into the air chamber 67. Thereby, the diaphragms 64 and 65 are deformed, the valve body 62 moves to the air chamber 67 side, and the interval between the small diameter portion 621 and the surface of the block 68 facing the inflow chamber 631 is reduced. As a result, the flow rate of pure water flowing from the inflow chamber 631 through the communication passage 633 to the outflow chamber 632 decreases, and therefore, pure water that flows out from the outflow chamber 632 toward the pure water flow rate adjustment valve 52 (see FIG. 1). Fluctuations in flow rate and pressure are suppressed.
[0022]
Conversely, when the flow rate or pressure of pure water flowing into the inflow chamber 631 decreases, the pressure of pure water flowing into the outflow chamber 632 from the inflow chamber 631 through the communication path 633 decreases, and the large diameter of the valve body 62 is reduced. The pressure that the portion 622 receives from pure water is smaller than the pressure in the air chamber 67. Thereby, the diaphragms 64 and 65 are deformed, the valve body 62 moves to the air chamber 66 side, and the interval between the small diameter portion 621 and the surface of the block 68 facing the inflow chamber 631 is increased. As a result, the flow rate of pure water flowing from the inflow chamber 631 through the communication passage 633 to the outflow chamber 632 increases, so that pure water flows out from the outflow chamber 632 toward the pure water flow rate adjustment valve 52 (see FIG. 1). Fluctuations in flow rate and pressure are suppressed.
[0023]
Since such an automatic pressure regulating valve 6 is interposed upstream of the pure water flow rate adjusting valve 52 in the pure water flow direction, the pressure and flow rate of pure water supplied to the pure water flow rate regulating valve 52 can be reduced. It can always be kept constant. Therefore, the flow rate of pure water discharged from the pure water supply nozzle 5 can be prevented from fluctuating due to pulsation, and the width of the processing region at the peripheral edge of the upper surface of the wafer W can always be maintained at a desired width.
In this embodiment, the setting air supplied to the air chamber 67 of the automatic pressure regulating valve 6 is supplied from an air supply source (not shown) via the air supply pipe 71. A precision pressure reducing valve 72 capable of precisely adjusting the pressure of the air supplied to the air chamber 67 is interposed in the pipe 71. Thereby, the pressure of the setting air supplied to the air chamber 67 can be adjusted with high accuracy, and the flow rate of pure water supplied from the automatic pressure adjusting valve 6 to the pure water flow rate adjusting valve 52 can be set with high accuracy. Can do.
[0024]
In order to perform the etching process on the back surface of the wafer W, as shown in FIG. 1, the back surface of the wafer W held by the spin chuck 1 is etched at the bottom of the processing cup 2 as shown in FIG. Nozzles 81 and 82 for supplying liquid may be provided. Further, a nozzle 83 for supplying an etching solution toward the center of the back surface of the wafer W held by the spin chuck 1 may be disposed at the upper end of the rotating shaft 12 of the spin chuck 1.
[0025]
Although one embodiment of the present invention has been described above, the present invention can be implemented in other forms. For example, in the above-described embodiment, a spin chuck that holds the peripheral portion of the wafer W is used. However, if the apparatus performs an etching process only on the peripheral portion and the end surface of the upper surface of the wafer W, the wafer W A vacuum chuck that attracts the lower surface may be applied.
The substrate to be processed is not limited to the wafer W, and may be other types of substrates such as a glass substrate for a liquid crystal display device, a glass substrate for a plasma display panel, and a magnetic / optical disk substrate.
[0026]
In addition, various design changes can be made within the scope of matters described in the claims.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing a configuration of a bevel etching apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a simplified configuration of an automatic pressure regulating valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Spin chuck 4 Etching liquid supply nozzle 5 Pure water supply nozzle 6 Automatic pressure adjustment valve 41 Etching liquid piping 42 Etching liquid flow rate adjustment valve 51 Pure water piping 52 Pure water flow rate adjustment valve
62 Disc
64 Diaphragm
65 Diaphragm
66 Air chamber
67 Air chamber
72 Precision pressure reducing valve
631 Inflow chamber
632 Outflow chamber
633 Communication passage W Wafer

Claims (4)

A bevel etching apparatus for selectively etching the peripheral edge of the upper surface of a substrate,
A substrate holding and rotating means for rotating the substrate while holding the substrate substantially horizontally;
Etching solution supply means for supplying an etching solution to the peripheral edge of the upper surface of the substrate rotated by the substrate holding rotation means;
A surface-protecting pure water nozzle for supplying pure water for protecting a region other than the peripheral portion of the substrate upper surface from the etching solution toward the upper surface of the substrate rotated by the substrate holding and rotating means,
Pure water piping through which pure water supplied from the surface protecting pure water nozzle to the upper surface of the substrate flows;
Middle is interposed in the deionized water pipe, viewed contains an automatic pressure regulating valve for maintaining substantially constant the pressure of the pure water flow direction downstream of the pure water in the pipe,
The automatic pressure regulating valve includes an inflow chamber into which pure water flows, an outflow chamber from which pure water flows out, a communication path that connects the inflow chamber and the outflow chamber, and a valve body that is inserted into the communication path. And when the flow rate or pressure of pure water flowing into the inflow chamber increases, the valve body moves so that the flow rate of pure water flowing from the inflow chamber through the communication path into the outflow chamber decreases, When the flow rate or pressure of pure water flowing into the inflow chamber decreases, the valve body moves so that the flow rate of pure water flowing from the inflow chamber through the communication path into the outflow chamber increases, thereby A bevel etching apparatus characterized by suppressing fluctuations in pressure of pure water flowing out of a chamber . A flow rate adjusting valve for adjusting the flow rate of pure water that is interposed in the middle of the pure water pipe and is supplied to the upper surface of the substrate from the pure water nozzle for surface protection;
2. The bevel etching apparatus according to claim 1, wherein the automatic pressure regulating valve is interposed upstream of the flow rate regulating valve in the pure water flow direction.   The automatic pressure regulating valve includes first and second diaphragms, a first air chamber that is adjacent to the inflow chamber with the first diaphragm interposed therebetween and in which air of constant pressure is sealed, and the second A second air chamber adjacent to the outflow chamber with a diaphragm interposed therebetween and supplied with setting air for setting the position of the valve body in a steady state. The bevel etching apparatus according to claim 1 or 2, wherein both ends are bonded to the second diaphragm.   4. The bevel etching apparatus according to claim 3, further comprising a precision pressure reducing valve for adjusting the pressure of the setting air supplied to the second air chamber.

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