JP5548973B2 - Etching method and etching apparatus - Google Patents

Description

The present invention relates to an etching method and an etching apparatus for etching an etching agent supplied from an etching nozzle toward the surface of a workpiece .

  2. Description of the Related Art Conventionally, machining methods such as lapping and polishing are widely used to process the surface of a workpiece such as a piezoelectric material such as quartz, a semiconductor material such as silicon, or a glass material substrate. However, in general, the machining method is difficult to process with a high accuracy such that the surface shape, thickness, and flatness of the workpiece are several μm or less, and in some cases, several μm or less.

  As one of surface processing methods other than machining, there is dry etching using reactive gas, excited active species such as radicals generated by plasma, ion beam and the like. In general, dry etching requires an expensive and complicated apparatus or facility for handling a highly reactive gas or generating plasma or ions, and is expensive. In particular, in the plasma etching method, since the temperature of the workpiece changes due to high heat generated by plasma, the etching rate is not constant and the processing accuracy may be reduced. Further, in the ion beam etching method, there is a possibility that the surface of the workpiece may be altered by ion impact, and post-treatment may be necessary to remove such an altered layer.

  Yet another surface processing method is wet etching using an etchant as an etchant. In general wet etching, the surface of a workpiece is immersed in an etching solution to process the surface, so that the work is easy and low-cost, and the etching rate is high. In this case, since the entire surface to be processed is uniformly etched, the unevenness on the original surface is transferred to the processed surface as it is. Therefore, when high shape accuracy and flatness of μm order, sub-μm order, and nm order are required, or when high precision surface processing is required partially, it may be difficult to realize this. is there.

  There is known a method for planarizing a semiconductor substrate that improves the flatness of the semiconductor substrate by wet etching and that does not cause damage after processing (see, for example, Patent Document 1). This method applies an active etchant from a nozzle to a part of a main surface of a semiconductor substrate immersed in an inert etchant, and immediately discharges the reacted etchant through a discharge pipe concentric with the nozzle, The nozzle is moved relative to each other, and a portion of the substrate having a large thickness, which has been measured in advance, is locally etched by a predetermined amount.

  Further, for wet processing methods such as etching, a liquid having a nozzle structure in which a wet processing liquid introduction passage and a discharge passage intersect at their ends and an opening is provided at the intersection toward the substrate. A supply nozzle has been proposed (see, for example, Patent Document 2). In the wet processing using this nozzle, the supplied wet processing liquid contacts the substrate through the opening and is discharged from the discharge passage by the decompression pump without leaking from the substrate to the outside. High cleanliness can be obtained with an amount of wet treatment liquid.

  Another etching apparatus that can easily and easily perform partial etching of a semiconductor wafer or the like is known (see, for example, Patent Document 3). The etching apparatus includes a wafer support unit that holds a wafer and moves the wafer to a predetermined position, and a chemical solution tube that is positioned below the wafer and has an opening end facing the lower surface thereof. Then, the liquid surface is supplied so as to form an upward convex curved surface due to surface tension, and etching is performed by contacting a predetermined etching portion of the wafer. The etching site immersed in the chemical solution is cleaned by switching after the etching process, supplying pure water to the chemical solution tube, and leaking from the open end.

  There is also known a wet etching apparatus and method that can efficiently etch a large area of a semiconductor substrate and locally etch a desired portion (see, for example, Patent Document 4). This etching apparatus is an etching head in which at least one opening is provided in a processing surface facing a processing surface of a semiconductor substrate in parallel, and the opening area is 0.1% to 85% with respect to the area of the processing surface. Is provided. This etching head supplies an etching solution from the opening of the processing surface and permeates between the processing surface and the surface to be processed by the capillary effect, and terminates the penetration of the etching solution at the end of the etching head or the semiconductor substrate by the surface tension. And holding this, the semiconductor substrate is etched. The processed surface after the etching process is cleaned by switching and supplying water from the opening of the processed surface of the etching head. Moreover, the etching liquid supplied to the surface to be processed can be recovered after the etching process by providing a separate recovery mechanism.

  The present inventor has already proposed a local wet etching method that enables local etching without using a mask by simultaneously supplying and collecting an etching agent with a nozzle having a double pipe structure ( For example, refer nonpatent literature 1 and patent literature 5.). This method was obtained from the difference between the profile before processing and the target profile measured in advance for each point on the surface of the workpiece while moving the etching agent supply means relatively along the surface of the workpiece. An etching agent is supplied according to the processing depth to etch the surface of the workpiece, and the liquid and gas near the surface are removed by suction.

  In the first aspect of the method, the supply means assembly in which a plurality of supply means for the etching agent are arranged is moved along the surface of the workpiece at a predetermined speed, and the temperature of the etching agent and / or each of the supply means is increased. The flow rate is controlled and supplied to the workpiece surface. In the second aspect of the method, the etching agent is supplied at a predetermined flow rate while the etching agent supply means is moved at a speed determined by the processing depth of each point on the surface of the workpiece. The liquid and gas near the surface of the workpiece are sucked and removed with a suction amount of. According to any aspect, the surface of various workpieces can be processed or finished into a desired shape (profile) with an accuracy of several nm to several μm, or the thickness of the workpiece can be made uniform.

  According to Patent Document 5, when an etching agent having a predetermined component and concentration is supplied at a predetermined flow rate, the etching amount of the workpiece, that is, the processing depth, is proportional to the time during which the surface is exposed to the etching agent. To do. Since the time during which the point on the workpiece surface is exposed to the etchant during the movement of the supply means is inversely proportional to the speed of the supply means at that point, the speed of the supply means depends on the processing depth at each point. Is determined.

  FIGS. 10A and 10B show the basic configuration of an etching nozzle suitable for use as an etching agent supply means in the local wet etching method. In the figure, an etching nozzle 1 has an inner tube 2 and an outer tube 3 arranged coaxially, and an inner opening 4 of the inner tube 2 and an outer opening 5 defined between the inner tube and the outer tube 3. Is arranged toward the surface 6 a of the workpiece 6. The etching solution 7 is supplied from the inner opening 4 to the workpiece surface 6a through the inner tube supply passage 8, and together with the gas and solid in the vicinity of the surface, from the outer opening 5 through the outer tube recovery passage 9. Removed by suction. As a result, the etching solution is sufficiently removed from the surface of the workpiece, and the possibility of excessive etching of the surface and its peripheral portion is eliminated.

  FIG. 10C shows a unit machining mark 10 formed when the surface 6 a is machined for a unit time while the nozzle 1 is stationary with respect to the workpiece 6. The unit processing mark 10 has a cylindrical shape defined by the outer diameter of the outer opening 5, and the spatial resolution of processing is determined by the size of the unit processing mark 10. Further, the processing amount is determined by the convolution of the unit processing trace and the residence time of the etching nozzle, and the scanning speed distribution of the etching nozzle is obtained by the deconvolution of the target processing amount and the unit processing trace. If the area of the unit processing trace is reduced, the spatial resolution is increased, and if the area is increased, the processing efficiency is increased.

  Further, the present inventor has proposed various other nozzle structures suitable for the local wet etching method (see, for example, Patent Document 5). The etching nozzle 11 shown in FIG. 11 (A) is composed of a nozzle assembly in which a plurality of nozzle units 12 having the same structure as those shown in FIGS. 10 (A) and 10 (B) are continuously arranged in a horizontal row. The nozzle unit 12 has an inner tube 13 and an outer tube 14 arranged coaxially. An etchant is supplied to the surface of the workpiece from the inner opening 15 of each inner tube 13 to etch the surface in a laterally elongated manner from the outer opening 16 defined between the inner tube and the outer tube 14. It is collected by suction.

FIG. 11B shows a modification of the etching nozzle of FIG. The nozzle 17 includes a plurality of inner tubes 18 arranged continuously in a horizontal row and one outer tube 19 arranged so as to surround them. An etchant is supplied to the surface of the workpiece from the inner opening 20 of each inner tube 18 to etch the surface in a laterally elongated manner from an outer opening 21 defined between the inner tube and the outer tube 19. It is collected by suction. The nozzles 11 and 17 in FIGS. 11A and 11B are moved in a direction perpendicular to the arrangement direction of the nozzles 12 or the inner pipes 18 so that a wide area on the surface of the workpiece is obtained by one scan. Can be processed at once.

  FIG. 11C shows another modification of the etching nozzle of FIG. The nozzle 22 is composed of a nozzle assembly in which a plurality of nozzle units 23 having the same structure as that shown in FIGS. The nozzle unit 23 has an inner tube 24 and an outer tube 25 arranged coaxially. The etching solution is supplied to the surface of the workpiece from the inner opening 26 of each inner tube 24 to etch the surface, and is sucked and collected from the outer opening 27 defined between the inner tube and the outer tube 25. . Thus, by disperse | distributing and arrange | positioning the some outer tube | pipe 25 to the nozzle 22 whole, an etching liquid and gas can be efficiently attracted | sucked from the workpiece surface.

  FIG. 12A shows still another configuration of an etching nozzle suitable for the local wet etching method. The nozzle 28 has a substantially rectangular inner tube 29 elongated in the lateral direction and an outer tube 30 disposed outside the inner tube 29. The inner tube 29 has a linear inner opening 31 that extends in the lateral direction, and a rectangular annular outer opening 32 that is elongated in the lateral direction is defined between the inner tube 29 and the outer tube 30. The etching solution is supplied to the surface of the workpiece from the inner opening 31, etches the surface into a long and narrow rectangular shape in the lateral direction, and is sucked and collected from the outer opening 32. By moving the nozzle 28 in a direction perpendicular to the lateral direction, the wide surface of the workpiece can be processed in one scan.

As shown in FIG. 12B, the nozzle 28 can be configured such that the lateral dimension of the outer opening 32 is somewhat wider than the lateral dimension of the workpiece 33. In this case, as indicated by an arrow in the figure, the surface of the workpiece 33 is uniformly processed over the entire width in one scan by moving the nozzle 28 in a direction orthogonal to the lateral direction. Can do.

JP 11-45872 A Japanese Patent Laid-Open No. 10-163153 JP 2004-6518 A JP 2008-21920 A JP 2007-200754 A

Hiroyuki Takai, “Preparation of high-precision optical elements by numerically controlled local wet etching”, Proceedings of the 2008 JSPE Spring Conference, Japan Society for Precision Engineering, March 2008, N36, p. 1081-1082

  As described above, in the local wet etching method, the spatial resolution is determined by the size of the unit processing mark formed by the etching nozzle to be used, and the area of the unit processing mark is determined by the outer opening of the processing nozzle. Further, the etching processing amount is proportional to the integrated amount of time that the etching agent stays on the surface of the workpiece, that is, the time that the surface is exposed to the etching agent. Therefore, when the processing depth of the workpiece changes along the moving direction of the etching nozzle, the workpiece surface is processed into a desired profile by adjusting and controlling the feed pitch in the nozzle moving direction. be able to.

The processing depth of the workpiece may change along a direction orthogonal to the moving direction of the etching nozzle. For example, when the surface of the workpiece is inclined in a direction perpendicular to the moving direction of the nozzle, such as a wafer having a thickness gradient, it may be required to process the inclined surface horizontally. In addition, the polished wafer tends to be thicker at the peripheral edge than the inner part. In such a case, it is necessary to delete the peripheral edge more and process the whole to a uniform thickness.

In such a case, if the spatial resolution of the etching nozzle, particularly the resolution in the direction orthogonal to the moving direction of the nozzle is sufficiently increased, the workpiece surface can be similarly processed into a desired profile. For this purpose, for example, the etching nozzle 1 of FIG. 10 may have a sufficiently small inner diameter of the outer tube 3, that is, an outer diameter of the outer opening 5. However, if the resolution in the direction orthogonal to the nozzle movement direction is increased, the feed pitch in the direction orthogonal to the nozzle movement direction is reduced accordingly, and the number of scans is increased, resulting in increased man-hours and reduced work efficiency and productivity. To do.

In the etching nozzles 17 and 28 of FIG. 11B and FIG. 12, the lateral dimensions of the outer openings 21 and 32 are large, and the depth of the processing mark is constant over the entire range . If an inclined surface is to be processed horizontally with such a nozzle, the feed pitch in the direction orthogonal to the moving direction of the nozzle must be reduced in accordance with the inclination, and scanning must be repeated repeatedly. As a result, the number of scans of the nozzle is extremely increased, man-hours are increased, work efficiency and productivity are lowered, and advanced technology and a control device for accurately and accurately controlling nozzle scanning are required. Become.

The etching nozzles 11 and 22 in FIGS. 11A and 11C adjust the flow rate and / or the temperature of the etching agent supplied to each nozzle unit along the lateral direction , thereby adjusting the lateral direction of the etching nozzle . It is possible to change the machining depth within a range of dimensions . However, in order to increase the processing accuracy, the tube diameter of the single nozzle must be made thinner, and in order to process a larger area, the number of single nozzles must be increased. Such an etching nozzle has a problem that the structure is complicated and the cost is high. Furthermore, in order to adjust the etching agent flow rate and the temperature of each nozzle unit with high accuracy while moving the entire etching nozzle, a very advanced control technique is required.

  In general, a quartz wafer used for a quartz device is thinner than a semiconductor wafer and often requires higher flatness. In particular, recently, with the increase in the frequency of quartz devices, quartz wafers tend to become larger and thinner. Therefore, not only is it difficult to handle crystal wafer etching, but it is also difficult to apply the semiconductor substrate processing technology described above in relation to the prior art as it is. There is a need for processing techniques to obtain.

Therefore, the present invention has been made in view of the above-described conventional problems, and its purpose is to simultaneously supply and collect an etching agent on the surface of a workpiece, particularly as in the local wet etching method. using an etching nozzle for have a double pipe structure suitable for use in wet etching, the desired profile of the surface of the workpiece, a small number as possible, preferably in one scan with different profiles It is another object of the present invention to provide an etching method that can be efficiently processed.

Another object of the present invention is to provide an etching apparatus that includes such an etching nozzle and can efficiently process the surface of a workpiece into a desired profile by wet etching.
Furthermore, the objective of this invention is providing the board | substrate processed into the desired profile by utilizing those etching methods and / or apparatuses.

In order to achieve the above object, an etching method of the present invention comprises an inner tube having an inner opening, and an outer tube disposed outside the inner tube and defining an outer opening between the inner tube and the inner tube . Preparing an etching nozzle in which the dimension in the width direction of the outer edge portion of the outer opening changes linearly in a direction perpendicular to the width direction;
The etching nozzle while sucking and collecting from the outer opening while supplying the etching agent from the inner opening to the surface of the workpiece while the inner opening and the outer opening of the etching nozzle are opposed to the surface of the workpiece. And moving at least one of the workpiece and the workpiece in the width direction;
It is characterized by including.

By preparing and using the etching nozzle in this way, the processed cross-sectional shape of the workpiece by etching can be determined by the outer peripheral shape of the outer opening of the etching nozzle. For example, when the difference between the cross-sectional profile before processing the workpiece and the target cross-sectional profile is used as the processing profile, the width dimension of the outer peripheral edge shape of the outer opening of the etching nozzle corresponding to the change in the processing profile Can be changed along the direction perpendicular to the width direction to etch the surface of the workpiece. Thus, according to the etching method of the present invention, the surface of a workpiece having various cross-sectional profiles can be efficiently formed into a desired profile, preferably with a single scan of the etching nozzle or with a smaller number of scans. Can be processed. Further, when the processing profile of the workpiece is uniformly inclined along the direction orthogonal to the width direction, the surface of the workpiece can be efficiently processed into a desired profile with a smaller number of scans. .

In order to achieve the above object, an etching method of the present invention comprises an inner tube having an inner opening, and an outer tube disposed outside the inner tube and defining an outer opening between the inner tube and the inner tube. a step of preparing an etching nozzle in which the hourglass gradually increasing toward the end in the direction of both end portions in the width direction dimension of the outer edge of the outer apertures are orthogonal to said width direction,
The etching nozzle while sucking and collecting from the outer opening while supplying the etching agent from the inner opening to the surface of the workpiece while the inner opening and the outer opening of the etching nozzle are opposed to the surface of the workpiece. And moving at least one of the workpiece and the workpiece in the width direction;
It is characterized by including.

  By preparing and using the etching nozzle in this way, the processed cross-sectional shape of the workpiece by etching can be determined by the outer peripheral shape of the outer opening of the etching nozzle. For example, when the difference between the cross-sectional profile before processing the workpiece and the target cross-sectional profile is used as the processing profile, the width dimension of the outer peripheral edge shape of the outer opening of the etching nozzle corresponding to the change in the processing profile Can be changed along the direction perpendicular to the width direction to etch the surface of the workpiece. Thus, according to the etching method of the present invention, the surface of a workpiece having various cross-sectional profiles can be efficiently formed into a desired profile, preferably with a single scan of the etching nozzle or with a smaller number of scans. Can be processed. Further, when the machining profile of the workpiece is partially changed within the dimension in the direction orthogonal to the width direction of the outer opening of the etching nozzle, the workpiece surface is reduced in accordance with the change. A desired profile can be efficiently processed by scanning a number of times.

In one embodiment, in the step of moving at least one of the etching nozzle and the workpiece, at least one of them moves linearly. As a result, a workpiece such as a rectangular wafer having a thickness gradient can be efficiently processed along the edge direction.

In yet another aspect, the etching apparatus of the present invention includes an inner tube having an inner opening, and an outer tube disposed outside the inner tube and defining an outer opening between the inner tube and the outer tube. An etching nozzle in which the dimension in the width direction of the outer edge of the opening linearly changes in a direction perpendicular to the width direction;
Supply means for supplying an etchant to the inner tube of the etching nozzle;
Recovery means for recovering an etchant from the outer tube of the etching nozzle;
Moving means for moving at least one of the etching nozzle and the workpiece while maintaining a distance between the etching nozzle and the workpiece;
A reservoir for storing the etchant supplied to and recovered from the outer tube of the etching nozzle;
Means for maintaining the reservoir etchant at a desired temperature;
It is characterized by providing.
Accordingly, the surface of the workpiece having various profiles can be efficiently processed into a desired profile while adjusting and controlling the temperature of the etching agent supplied to the surface of the workpiece by wet etching.
In yet another aspect, the etching apparatus of the present invention includes an inner tube having an inner opening, and an outer tube disposed outside the inner tube and defining an outer opening between the inner tube and the outer tube. and etching the nozzle the width dimension of the outer edge of the apertures has an hourglass shape that gradually increases toward the end at both end portions in the direction perpendicular to the width direction,
Supply means for supplying an etchant to the inner tube of the etching nozzle;
Recovery means for recovering an etchant from the outer tube of the etching nozzle;
Moving means for moving at least one of the etching nozzle and the workpiece while maintaining a distance between the etching nozzle and the workpiece;
A reservoir for storing the etchant supplied to and recovered from the outer tube of the etching nozzle;
Means for maintaining the reservoir etchant at a desired temperature;
It is characterized by providing.

Some embodiments further comprise means for circulating the etchant stored in the reservoir to the inner tube. Thereby, while reducing the usage-amount of an etching agent and reducing processing cost, the influence which an etching agent can have on an environment can be suppressed.

(A) is a longitudinal sectional view of a first embodiment of an etching nozzle according to the present invention, and (B) is an end view showing an opening of the nozzle. The schematic block diagram of the etching apparatus using the nozzle of 1st Example. Sectional drawing of the process trace formed in a workpiece by the nozzle of 1st Example. FIG. 4A is a sectional view of a wafer processed by the nozzle of the first embodiment, and FIG. 4B is a plan view for explaining the scanning procedure of the nozzle. (A) is a longitudinal sectional view of a second embodiment of an etching nozzle according to the present invention, and (B) is an end view showing an opening of the nozzle. Sectional drawing of the process trace formed in a workpiece by the nozzle of 2nd Example. FIG. 4A is a sectional view of a wafer processed by the nozzle of the second embodiment, and FIG. 4B is a plan view for explaining the scanning procedure of the nozzle. FIG. 4A is a longitudinal sectional view of an etching nozzle having a basic configuration for processing a circular wafer, and FIG. 4B is an end view of the nozzle. (A) A figure is a longitudinal cross-sectional view of the 3rd Example of the etching nozzle by this invention, (B) A figure is a figure which shows the outer periphery periphery shape of the outer side opening of this nozzle. (A) is a longitudinal sectional view showing a configuration of a conventional etching nozzle, (B) is an end view showing an opening of the nozzle, and (B) is a longitudinal sectional view showing a unit machining trace. (A) is an end view showing another configuration of a conventional etching nozzle, (B) is an end view showing a modification thereof, and (C) is an end view showing another modification. (A) is an end view showing another configuration of a conventional etching nozzle, and (B) is a diagram for explaining the scanning procedure of the nozzle.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
1A and 1B schematically show the configuration of a first embodiment of an etching nozzle according to the present invention. The etching nozzle 41 of this embodiment includes a double pipe structure including an inner tube 42 and an outer tube 43 disposed outside the inner tube 42. The inner tube 42 is provided with an inner opening 44 at the tip thereof, and the outer tube 43 defines an outer opening 45 between the inner tube 42 and the inner tube. The inner opening 44 is connected to an etching agent supply source via a supply passage 46 inside the inner tube, and the outer opening 45 is connected to an etching agent recovery device via a recovery passage 47 inside the outer tube. .

  The outer opening 45 is symmetrical with respect to the center line in the left-right direction, and has an isosceles trapezoidal outer peripheral edge shape composed of a long side on the left side and a short side on the right side, and an oblique side on the upper side and the lower side. The inner opening 44 also has an isosceles trapezoidal outer peripheral shape that is generally similar to the outer opening. Similarly, the inner tube 42 and the outer tube 43 of this embodiment have an isosceles trapezoidal cross-sectional outer shape that is generally similar to the outer opening. However, in another embodiment, the cross-sectional outer shape can be various shapes other than the isosceles trapezoid.

In this embodiment, the direction along the moving direction A of the etching nozzle 41 is the first direction, and the direction orthogonal to the direction is the second direction. The outer opening 45 is elongated in the left-right direction, that is, the second direction in the drawing, and the dimension L in the first direction , that is , the dimension in the width direction changes linearly along the second direction over the entire range . The etching nozzle 41 has the inner opening 44 and the outer opening 45 opposed to the surface of the workpiece 48, and the direction perpendicular to the horizontal center line of the outer opening coincides with the movement direction A, that is, the first direction. Deploy.

  The etching solution is supplied to the surface of the workpiece 48 from the inner opening 44 through the supply passage 46 while moving the nozzle along the moving direction A, and etches the surface. Thereafter, the etching solution is sucked and removed from the outer opening 45 through the recovery passage 47 together with the gas and solid in the vicinity of the surface.

FIG. 2 schematically shows the configuration of an embodiment of an etching apparatus according to the present invention. The etching apparatus 51 of this embodiment includes the etching nozzle 41 shown in FIGS. 1A and 1B and a reservoir 53 for storing the etching solution 52. The reservoir 53 is connected to the recovery passage 47 of the etching nozzle 41 by a pipe line 54. By reducing the pressure in the reservoir 53 with the suction pump 54, the etching solution after processing the workpiece surface 48 a can be sucked from the outer opening 45 through the collection passage 47 and collected in the reservoir. At this time, the etching nozzle 41 is held so that the inner opening 44 and the outer opening 45 keep a distance from the surface 48a of the workpiece, as shown.

  The reservoir 53 is further connected to a supply passage 47 of the etching nozzle 41 by a pipe 56. The conduit 56 is provided with a liquid feed pump 57, a flow rate adjusting valve 58 and a flow meter 59, and supplies the etching solution in the reservoir 53 to the supply passage 47 while controlling the flow rate. In this manner, a circulation system is configured in which an etching agent is supplied to the etching nozzle 41, recovered after the workpiece 48 is processed, and supplied again to the etching nozzle. In another embodiment, the etching solution source may be provided separately from the reservoir.

  The reservoir 53 is provided with a heater 60 with a temperature sensor, and an etching solution in the reservoir is set and / or maintained at a desired temperature by a temperature controller 61 connected to the heater. By such a temperature control mechanism, the temperature of the etching solution supplied to the workpiece surface 48a can be adjusted and controlled according to the processing depth while taking the moving speed of the etching nozzle 41 into consideration.

The etching apparatus 51 includes moving means (not shown) for moving the etching nozzle 41 relative to the workpiece 48. In one embodiment, the moving means can move the etching nozzle 41 linearly or circumferentially, or move it in the XY directions orthogonal to each other to process a large area. In another embodiment, the moving means can move or rotate the workpiece 48 linearly, or can be fixed to an XY table or the like and moved in the orthogonal XY directions. In another embodiment, the etching nozzle 41 can be moved in the X direction, and the workpiece 48 can be moved in the Y direction orthogonal thereto. The moving means can maintain a distance between the inner opening 44 and the outer opening 45 of the etching nozzle 41 and the surface 48a of the workpiece.

  FIG. 3 shows a process that is formed on the surface of the workpiece when the surface 48a is etched while moving the etching nozzle 41 of the first embodiment relative to the workpiece 48 at a constant speed. The cross-sectional shape of the groove 62 is shown. The processing groove 62 is formed in a cross-sectional shape in which the bottom surface 62a is inclined at a certain angle along the second direction.

Each point on the workpiece surface 48a is exposed to the etchant while the point is within the range of the outer peripheral edge of the outer opening 45 of the nozzle on the plane. As described above, the outer peripheral edge of the outer opening 45 has an isosceles trapezoidal shape, and the dimension L in the first direction changes linearly along the second direction over the entire range in the second direction. Since the etching amount is proportional to the integrated amount of time that the surface of the workpiece is exposed to the etching agent, each point on the surface of the workpiece is exposed to the etching agent in proportion to the dimension L in the first direction. Becomes longer and the amount of etching process increases. Therefore, the inclination of the machining groove bottom surface 62a is determined by the inclination of the change in the dimension L in the first direction of the outer opening.

  The etching nozzle 41 of the first embodiment is suitable for etching an inclined surface horizontally, for example. 4A and 4B show a procedure for processing the surface 63a of the wafer 63 having a thickness gradient into a horizontal plane. Here, as shown in FIG. 4A, a difference between a cross-sectional profile of the inclined surface 63a before processing and a target cross-sectional profile that is a horizontal plane indicated by an imaginary line 64 is a processing profile. In this embodiment, the machining profile has a wedge shape that gently slopes from the left side to the right side in the drawing.

  FIG. 4B is a view of the front surface 63a of the wafer 63 arranged horizontally as viewed from below. In this figure, the direction orthogonal to the tilt direction of the wafer surface 63a is the main scanning direction X of the etching nozzle 41, and the tilt direction is the sub-scanning direction Y.

  The etching nozzle 41 etches the wafer surface 63a by supplying an etchant while linearly moving from the lower end of the wafer 63 to the upper end of the wafer 63 at a constant speed. By a single scan of the etching nozzle 41, a linear processing groove 65 is formed on the surface 63a of the wafer 63. As shown in FIG. 4A, the processing groove 65 has a horizontal bottom surface at the same depth as the target cross-sectional profile 64.

  The moving speed of the etching nozzle 41 is determined from the processing depth and the etching rate based on the processing profile. The etching rate can be controlled by adjusting the type, concentration, flow rate, temperature, etc. of the etching solution to be used, if necessary. When a sufficient processing amount cannot be obtained by one scan, the processing groove 65 having a desired depth can be formed by repeatedly scanning the nozzles repeatedly.

When reaching the upper end of the wafer, the etching nozzle 41 is moved to the right in the figure in the Y direction. The feed amount in the Y direction is determined by the maximum dimension in the second direction of the outer opening 43 of the nozzle. Further, the nozzle is moved linearly from the upper end to the lower end of the wafer 63 at a constant speed parallel to the processing groove 65. When the nozzle reaches the lower end of the wafer, it is moved to the right in the figure in the Y direction with the same feed amount. Then, the wafer is linearly moved from the lower end to the upper end at a constant speed. In this way, the target cross-sectional profile 64 can be formed on the wafer 63 by supplying the etching solution and etching the surface while scanning the entire surface of the wafer surface 63 a to be processed by the etching nozzle 41.

  FIGS. 5A and 5B schematically show the structure of a second embodiment of the etching nozzle according to the present invention. Similarly, the etching nozzle 71 of the present embodiment has a double pipe structure including an inner tube 72 and an outer tube 73 disposed outside the inner tube 72. The inner tube 72 is provided with an inner opening 74 at the tip thereof, and the outer tube 73 defines an outer opening 75 between the inner tube 72 and the inner tube. The inner opening 74 is connected to an etching agent supply source via a supply passage 76 inside the inner pipe, and the outer opening 75 is connected to an etching agent recovery device via a recovery passage 77 inside the outer pipe. .

  The outer opening 75 is symmetric with respect to the center line in the vertical direction and the horizontal direction, the straight left and right sides are parallel to each other, the upper and lower sides are parallel to each other in the central portion, and then linearly extend toward the left and right ends. It has a generally drum-shaped outer peripheral shape that is inclined to the right. The inner opening 74 also has a drum-shaped outer peripheral edge shape that is generally similar to the outer opening. The inner tube 72 and the outer tube 73 of the present embodiment have a drum shape whose cross-sectional outer shape is similar to that of the outer opening, but can have various other shapes.

  Also in this embodiment, the direction along the moving direction A of the etching nozzle 71 is a first direction, and the direction orthogonal thereto is a second direction. The outer opening 75 is elongated in the left-right direction, that is, the second direction, and the dimension L in the first direction is constant in the central portion along the second direction, and increases linearly from the central portion toward the left and right ends. The direction has changed. The etching nozzle 71 is disposed so that the inner opening 74 and the outer opening 75 are opposed to the surface of the workpiece 78, and the vertical center line of the outer opening is aligned with the moving direction A, that is, the first direction.

  The etching solution is supplied to the surface of the workpiece 78 from the inner opening 74 through the supply passage 76 while moving the nozzle along the moving direction A, and etches the surface. Thereafter, the etching solution is sucked and removed from the outer opening 75 through the recovery passage 77 together with the gas and solid in the vicinity of the surface.

  The etching nozzle 71 of the second embodiment can be used in the etching apparatus of FIG. 2 in place of the etching nozzle 41 of the first embodiment. FIG. 6 shows a process formed on the surface of the workpiece when the etching nozzle 71 of the second embodiment is moved at a constant speed relative to the workpiece 78 and the surface 78a is etched. The cross-sectional shape of the groove 79 is shown. The processing groove 79 is formed in a cross-sectional shape in which the bottom surface 79a is inclined so that the central portion has a constant depth along the second direction and deepens at a certain angle from the central portion toward the left and right ends. .

  As described above in the first embodiment, each point on the workpiece surface 78a is exposed to the etching agent while the point is included in the range of the outer peripheral edge of the outer opening 75 of the nozzle on the plane. The amount of processing is proportional to the integrated amount of time that the etching agent is exposed to the etching agent on the surface of the workpiece. Since the outer peripheral edge of the outer opening 75 has the above-described drum shape, the inclination of the processed groove bottom surface 79a near both left and right ends is determined by the inclination of the change in the dimension L of the outer opening 75 in the first direction.

The etching nozzle 71 of the second embodiment is suitable, for example, for flatly etching the entire surface that is flat along the second direction and that is flat at the left and right sides, and is raised. As described above, the quartz wafer after polishing is thicker in the vicinity of the edge than the inner part. 7 (A) and 7 (B) show a wafer 80 having a cross-sectional shape in which the inner portion is flat and the vicinity of the right and left edges is inclined and becomes high, and the entire surface 80a is flat and the whole wafer is platen. The point of processing to make the thickness uniform is shown. Here, as shown in FIG. 7A, the difference between the cross-sectional profile of the surface 80a before processing and the target cross-sectional profile that is a flat surface indicated by the imaginary line 81 is the processing profile. In this embodiment, the machining profile has a shape obtained by vertically inverting the cross-sectional shape of the machining groove 79 shown in FIG.

FIG. 7B is a view of the surface 80a of the wafer 80 arranged horizontally as viewed from below. As can be seen from the figure, the etching nozzle 71 has a width in the second direction of the outer opening 75 that is slightly larger than the width of the wafer 80 and is within the range of the dimension in the second direction of the outer opening . Arrange to fit. While moving the etching nozzle 71 from the lower end of the wafer 80 toward the upper end in a straight line at a constant speed, the etching liquid is supplied to etch the wafer surface 80a.

The outer opening 75 of the nozzle matches the position of the central portion where the dimension L in the first direction is constant and the dimension in the second direction with the flat inner portion of the wafer 80, and from the central portion to the left and right ends. An outer peripheral shape is formed such that the inclination of the change in the dimension L in the first direction corresponds to the inclination near the left and right edges of the wafer. Thereby, the surface 80a of the wafer 80 can be processed into a target flat surface by one scanning of the etching nozzle 71.

  The moving speed of the etching nozzle 41 is determined from the processing depth and the etching rate based on the processing profile. The etching rate can be controlled by adjusting the type, concentration, flow rate, temperature, etc. of the etching solution to be used, if necessary. When a sufficient amount of etching processing cannot be obtained by one scan, the wafer 80 can be processed into a flat surface having a desired depth by repeatedly scanning the nozzles.

  In each of the above embodiments, the case where the etching nozzle is linearly moved along the surface of the workpiece has been described. However, the etching nozzle of the present invention can etch the surface of the workpiece while rotating relative to the workpiece and moving it around a certain point in the circumferential direction. For example, when etching the surface of a circular wafer, it is preferable to move the etching nozzle in the circumferential direction.

  8A and 8B schematically show an etching nozzle having a basic structure for etching the surface 90a of the circular wafer 90. FIG. In the same figure, the etching nozzle 91 is similarly provided with a double pipe structure composed of an inner tube 92 and an outer tube 93 disposed outside thereof. The inner tube 92 is provided with an inner opening 94 at the tip thereof, and the outer tube 93 defines an outer opening 95 between the inner tube 92 and the inner tube. The inner opening 94 is connected to an etching agent supply source via a supply passage 96 inside the inner tube, and the outer opening 75 is connected to an etching agent recovery device via a recovery passage 97 inside the outer tube. .

  As shown in FIG. 8B, the outer opening 95 includes upper and lower radius portions 95a and 95b opened at a predetermined angle θ (radian) around a point O on the right side in the drawing, and an arc connecting them. It has a generally fan-shaped outer peripheral shape composed of a portion. The inner opening 94 also has a fan-shaped outer peripheral shape that is generally similar to the outer opening. In the same figure, the inner tube 92 and the outer tube 93 have a sector shape whose cross-sectional outer shape is substantially similar to that of the outer opening, but can have various other shapes.

  The etching nozzle 91 rotates around the sector center point O of the outer opening 95 and moves along the circumferential direction A. In this case, the moving direction of the nozzle, that is, the circumferential direction A is defined as the first direction, and the radial direction orthogonal thereto is defined as the second direction. In the outer peripheral edge shape of the outer opening 75, the dimension in the second direction can be expressed by the distance from the center point O, that is, the radius, and the dimension in the first direction can be expressed by the arc length centered on the center point O. That is, the dimension L in the first direction of the outer opening 75 at a point on the lower radius portion 95b at a distance R from the center point O is always L = R · θ.

  The etching nozzle 91 aligns the center point O with the center position of the circular wafer 90, and arranges the inner opening 94 and the outer opening 95 to face the wafer surface 90a. The outer opening 95 has such a size that the arc portion is located slightly outside the outer peripheral edge of the circular wafer 90. Accordingly, when the nozzle is rotated 360 °, the entire surface 90a of the circular wafer 90 can be scanned. The etching solution is supplied from the inner opening 94 to the wafer surface 90a through the supply passage 96 while moving the nozzle along the circumferential direction A, and etches the surface. Thereafter, the etching solution is sucked and removed from the outer opening 95 through the recovery passage 97 together with the gas and solid near the surface.

  The moving velocity V of the etching nozzle 91 at a certain point P on the wafer surface 90a is V = r · ω, where r is the distance from the center point O of the point P, that is, the radius, where ω is the rotational angular velocity. . The time for which the point P is exposed to the etching solution is calculated by dividing the dimension L in the first direction of the outer opening of the nozzle passing through the point P by the moving speed V of the nozzle. At this time, since R = r, the time t during which the point P is exposed to the etching solution regardless of the position of the wafer surface 90a is t = R · θ / r · ω = θ / ω and is constant. is there.

  As described above, the etching processing amount is proportional to the integrated amount of time during which the surface of the workpiece is exposed to the etching agent. Therefore, the surface 90a of the wafer 90 is processed to a uniform depth. The difference between the cross-sectional profile 96 obtained in this way and the cross-sectional profile of the original surface 90a becomes a processing profile. As described above, the time t during which the wafer surface is exposed to the etching solution is a function of the opening angle θ of the outer opening 95 of the etching nozzle 91. Therefore, by determining θ corresponding to the processing file, The wafer surface 90a can be processed into a target cross-sectional profile by one scan of the nozzle.

  According to the present invention, based on such a basic configuration, the surface of the workpiece whose cross-sectional shape changes in the radial direction can be processed into a desired cross-sectional profile. FIGS. 9A and 9B show etching nozzles according to the present invention suitable for processing the surface 100a of the circular wafer 100 whose plate thickness varies in the radial direction as after the polishing process to a flat and uniform thickness. The structure of 3rd Example of this is shown schematically.

  Similarly, the etching nozzle 101 of this embodiment includes a double pipe structure including an inner tube 102 and an outer tube 103 disposed outside the inner tube 102. The inner tube 102 is provided with an inner opening 1044 at its tip, and the outer tube 103 defines an outer opening 105 between the inner tube and the inner tube. The inner opening 104 is connected to an etching agent supply source via a supply passage 106 inside the inner tube, and the outer opening 105 is connected to an etching agent recovery device via a recovery passage 107 inside the outer tube. .

  As shown in FIG. 9A, the wafer surface 100a has a cross-sectional profile that protrudes from the vicinity of the central position in the radial direction to the center and is inclined toward the outer peripheral edge over the entire circumference. A flat surface indicated by an imaginary line 106 in the figure is a target cross-sectional profile, and a difference between this and the cross-sectional profile of the original surface 100a is a processing profile.

  As shown in FIG. 9 (B), the outer opening 105 has a generally fan-shaped outer side composed of upper and lower radius portions 105a and 105b opened around a point O on the right side in the drawing and an arc portion connecting them. It has a peripheral shape. The lower radius portion 105b extends straight from the point O, whereas the upper radius portion 105 extends in a curved shape from the point O to the arc portion. The curved shape of the upper radius portion 105 is determined corresponding to the processing profile of the wafer 100.

  Further, the outer shape of the cross section of the outer tube 103 is a sector shape in which the upper and lower radial portions extend straight, as in the case of FIG. 8, but can be various other shapes. Although not shown, the cross-sectional outer shape of the inner tube 102 and the outer peripheral edge shape of the inner opening 104 can be formed in a sector shape that is generally similar to the outer opening, or can have various other shapes.

  Similar to the etching nozzle 91 in FIG. 8, the etching nozzle 101 is rotated around the sector center O of the outer opening 105 and moved along the circumferential direction A. A moving direction of the nozzle, that is, a circumferential direction A is defined as a first direction, and a radial direction perpendicular thereto is defined as a second direction. In the outer peripheral edge shape of the outer opening 105, the dimension in the second direction can be expressed by the distance from the center point O, that is, the radius, and the dimension in the first direction can be expressed by the arc length centered on the center point O.

  The etching nozzle 101 aligns the center point O with the center position of the circular wafer 100, and arranges the inner opening 104 and the outer opening 105 so as to face the wafer surface 100a. The outer opening 105 has a size such that the arc portion is located slightly outside the outer peripheral edge of the wafer. Accordingly, when the nozzle is rotated 360 °, the entire surface of the wafer surface 100a can be scanned. The etching solution is supplied from the inner opening 104 to the wafer surface 100a through the supply passage 106 while moving the nozzle along the circumferential direction A, and etches the surface. Thereafter, the etching solution is sucked and removed from the outer opening 105 through the recovery passage 107 together with the gas and solid in the vicinity of the surface.

  As described above with reference to the etching nozzle 91 of FIG. 8, the etching processing amount is determined by the fan-shaped opening angle θ of the outer opening 95. In this embodiment, as shown in FIG. 9A, when the processing depth at the position of the radius r0 where the plate thickness of the wafer 100 is the thinnest is dmin, the outer opening 105 of the etching nozzle 101 corresponding to this position is the first. At the position in the two directions, the opening angle around the point O of the outer opening is the minimum value θmin. Therefore, the dimension in the first direction at the position is the minimum value Lmin = r0 · θmin. The minimum value θmin of the opening angle is determined by the minimum value dmin of the processing depth and the etching rate.

  In the case of this embodiment, the etching processing amount at an arbitrary point P on the wafer surface 100a varies depending on the dimension of the outer opening 105 corresponding to that point in the first direction.

  The processing depth d at an arbitrary point P on the wafer surface 10a is expressed by d = dmin + Δd, where Δd is the amount of processing depth variation corresponding to the variation in the thickness of the wafer. At the position in the second direction of the outer opening 105 of the etching nozzle 101 corresponding to the point P, the dimension in the first direction is represented by L = Lmin + ΔL. Here, ΔL is the variation amount of the dimension in the first direction corresponding to the variation amount Δd of the machining depth. The amount of variation ΔL in the first direction can be calculated based on Δd from the ratio of the minimum value Lmin in the first direction to the minimum value dmin in the machining depth.

  The dimension L in the first direction at an arbitrary position in the second direction of the outer opening 105 is L = R · θ by the dimension in the second direction at that position, that is, the radius R, and the opening angle θ about the point O. It is represented by The opening angle θ at an arbitrary position in the second direction is expressed as θ = θmin + Δθ, where Δθ is a variation amount of the opening angle corresponding to the variation amount ΔL of the dimension in the first direction. Therefore, the variation amount of the opening angle is represented by Δθ = ΔL / R. Based on this relational expression, the curved shape of the upper radius portion 105a can be easily formed. By determining the outer peripheral edge shape of the outer opening 105 in this way, the wafer surface 100a can be processed into the target cross-sectional profile 106 by one scan of the etching nozzle 101.

  In another embodiment, the lower radius portion 105b of the outer opening 105 can have the same curved shape as the upper radius portion 105a of the above embodiment, and the upper radius portion 105a can be formed in a straight line. In another embodiment, both the upper and lower radii 105a and 105b of the outer opening 105 can be curved. Also in this case, the target machining shape can be obtained by setting the dimension L in the first direction of the outer opening 105 in the same manner as in the above embodiment along the second direction.

  Similarly to the first and second embodiments, the etching nozzle 101 of the third embodiment can be mounted on the etching apparatus 51 shown in FIG. In this case, the moving means of the etching nozzle 101 is configured to rotate relative to the workpiece and move in the circumferential direction. This moving means can fix the workpiece and move the etching nozzle 101, or fix the etching nozzle and move the workpiece, or both.

  The present invention is not limited to the above embodiments, and can be implemented with various modifications or changes within the technical scope thereof. For example, in the etching nozzles of the first and second embodiments, the dimension of the outer opening in the first direction changes linearly along the second direction in accordance with the processing profile of the workpiece. However, if the work profile of the workpiece is curved, the desired dimension can be similarly obtained by changing the dimension of the outer opening in the first direction so as to be curved along the second direction corresponding to the curve. Can be obtained. The present invention can be similarly applied not only to quartz wafers but also to other piezoelectric materials, wafers of semiconductor materials such as silicon or glass materials, and workpieces of various forms.

1,11,17,22,28,41,71,91,101 ... etching nozzle, 2,13,18,24,29,42,72,92,102 ... inner tube, 3,14,19,25, 30, 43, 73, 93, 103 ... outer tube, 4, 15, 20, 26, 31, 44, 73, 93, 103 ... inner opening, 5, 16, 21, 27, 32, 45, 75, 95, 105 ... outside opening, 6,33,48,78 ... workpiece, 6a, 48a, 63a, 78a, 80a, 90a, 10a ... surface, 7,52 ... etching solution, 8,46,76 ... supply passage, 9 , 47, 77 ... recovery passageway, 10 ... unit processing trace, 12, 23 ... single nozzle, 51 ... etching device, 62, 79 ... processing groove, 62a, 79a ... bottom surface, 63, 80, 90, 100 ... wafer, 64 , 81, 96, 106 ... cross-section professional Airu, 95a, 95b, 105a, 105b ... radius part.

Claims (5)

An inner tube having an inner opening, and an outer tube disposed outside the inner tube and defining an outer opening between the inner tube and a dimension in a width direction of an outer edge portion of the outer opening is the width direction Preparing an etching nozzle that linearly changes in a direction orthogonal to
The etching nozzle while sucking and collecting from the outer opening while supplying the etching agent from the inner opening to the surface of the workpiece while the inner opening and the outer opening of the etching nozzle are opposed to the surface of the workpiece. And moving at least one of the workpiece and the workpiece in the width direction;
An etching method comprising: An inner tube having an inner opening, is arranged outside of the inner tube and an outer tube defining an outer opening between the inner tube, the width dimension of the outer edge of the outer apertures is the width Preparing a drum-shaped etching nozzle that gradually increases toward the end at both ends in a direction orthogonal to the direction;
The etching nozzle while sucking and collecting from the outer opening while supplying the etching agent from the inner opening to the surface of the workpiece while the inner opening and the outer opening of the etching nozzle are opposed to the surface of the workpiece. And moving at least one of the workpiece and the workpiece in the width direction;
An etching method comprising: In the step of the mobile, the etching method according to claim 1 or 2, wherein at least one of an etching nozzle and the workpiece thus being moved linearly. An inner tube having an inner opening, and an outer tube disposed outside the inner tube and defining an outer opening between the inner tube and a dimension in a width direction of an outer edge portion of the outer opening is the width direction An etching nozzle that linearly changes in a direction perpendicular to
Supply means for supplying an etchant to the inner tube of the etching nozzle;
Recovery means for recovering an etchant from the outer tube of the etching nozzle;
Moving means for moving at least one of the etching nozzle and the workpiece while maintaining a distance between the etching nozzle and the workpiece;
A reservoir for storing the etchant supplied to and recovered from the outer tube of the etching nozzle;
Means for maintaining the reservoir etchant at a desired temperature;
An etching apparatus comprising: An inner tube having an inner opening, is arranged outside of the inner tube and an outer tube defining an outer opening between the inner tube, the width dimension of the outer edge of the outer apertures is the width An etching nozzle having a drum shape that gradually increases toward the end at both ends in a direction orthogonal to the direction;
Supply means for supplying an etchant to the inner tube of the etching nozzle;
Recovery means for recovering an etchant from the outer tube of the etching nozzle;
Moving means for moving at least one of the etching nozzle and the workpiece while maintaining a distance between the etching nozzle and the workpiece;
A reservoir for storing the etchant supplied to and recovered from the outer tube of the etching nozzle;
Means for maintaining the reservoir etchant at a desired temperature;
An etching apparatus comprising:

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