JP2010003805A - Wet-etching jig and wet-etching apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wet-etching jig and a wet-etching apparatus which can reduce etching variations due to hydrogen bubbles in an etching processing. <P>SOLUTION: A wet-etching jig 3 holds a substrate 11 in which etching is carried out by immersing in an alkaline liquid 2. The jig 3 has a wiper 13, which removes bubbles 16 on the surface of the substrate 11 by being relatively moved to the surface of the substrate 11 held in the jig 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a jig for wet etching and a wet etching apparatus in a product manufacturing field including wet etching using a chemical solution such as semiconductor manufacturing in the process.

  Conventionally, in this type of wet etching method, for example, Patent Document 1 discloses a wet etching apparatus that achieves high etching efficiency. This conventional wet etching apparatus is provided with supply means for supplying an etching solution into the inside from the bottom of a carrier on which a silicon substrate, which is a material to be etched, is arranged.

  FIG. 8 shows a cross-sectional view of an example of a silicon substrate showing the state before and after the conventional wet etching. FIG. 8A shows a state before the wet etching is performed, and FIG. 8B shows a state of attachment of hydrogen bubbles after the wet etching is performed.

As shown in FIG. 8A, the semiconductor element 102 is formed on the surface of the silicon substrate 101. Since it is necessary to protect the semiconductor element 102 manufactured on the surface of the silicon substrate 101 from an alkaline etching solution, a protective film 103 is applied on the semiconductor element 102. As the protective film 103, it is known that a cyclized rubber coating agent is applied by a spin coating method. Etching grooves 104 are formed on the back surface of the silicon substrate 101 by wet etching with an alkaline etchant, as shown in FIG. During this etching process, hydrogen bubbles 16 are generated from the etched surface.
Japanese Utility Model Publication No. 1-1136166

  As described above, when hydrogen bubbles adhere and stagnate on the surface of the protective film, a large amount of hydrogen exists in the system, which may hinder the progress of etching.

  In addition, due to the temperature distribution characteristics of the etching solution, the etching rate in the etching groove in the silicon substrate may be sparse, and the etching uniformity may be impaired.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a wet etching jig and a wet etching apparatus capable of suppressing and reducing etching progress due to hydrogen bubbles in an etching process and suppressing variations in etching.

  The jig | tool for wet etching of this invention hold | maintains the board | substrate with which etching is made by being immersed in etching liquid. The jig of the present invention has a wiper that removes bubbles attached to the surface of the substrate by moving relative to the surface of the substrate held by the jig.

  According to the present invention, variations in etching can be suppressed and reduced.

  Hereinafter, embodiments of the present invention in a wet etching jig and a wet etching method will be described with reference to the drawings.

  FIG. 1 shows a configuration diagram of the wet etching apparatus of this embodiment.

  The wet etching apparatus 1 of the present embodiment includes a jig 3 that holds a plurality of silicon substrates 11 that are rotationally driven by a motor 9 that is a driving means in a processing tank 6. The jig 3 has a wiper 13 that moves relative to the surface of the substrate 11 to remove bubbles on the surface of the substrate 11. In addition, an injection nozzle 5 for injecting an alkaline etching solution 2 as a wet etching solution into the processing bath 6 is provided on the bottom surface of the processing bath 6. Various alkali etching solutions 2 are assumed, but in this embodiment, TMAH (tetramethylammonium hydroxide) is used. Further, a heater for heating is installed in a pipe through which the alkali etching solution 2 circulates, and the alkali etching solution 2 is heated and maintained at a constant temperature. In FIGS. 1A and 1B, for the sake of simplification, the heater, the overflow tank, the water washing tank, the filter, the circulation pump, and the piping connecting them are omitted.

  Next, the configuration of the jig 3 will be described in detail with reference to FIGS.

  FIG. 2 is a configuration diagram of the jig according to the present embodiment, FIG. 2 (a) is a front view, and FIG. 2 (b) is a side view. FIG. 3 is a schematic view of the cut surface of the jig at the kk portion shown in FIG. FIG. 4 is a front view of the wiper.

  The jig 3 is rotatably held at the upper ends of the two support members 7 provided in the processing tank 6. The jig 3 includes two side plates 3 a, four support rods 18 that couple the two side plates 3 a, a plurality of wipers 13, and a pressing rod 12 that presses against the substrate 11.

  A drive gear 3b is provided on one of the two side plates 3a. The driving force of the motor 9 is transmitted to the rotating gear unit 7 via the shaft 8 and then to the driving gear 3b.

  As shown in FIG. 3, the four support rods 18 are arranged to open upward so that the substrate 11 can be placed thereon. That is, in the state of FIG. 3, the two support rods 18 a out of the support rods 18 restrict the movement of the substrate 11 in the left-right direction. On the other hand, the remaining two indicating rods 18b restrict the downward movement of the substrate 11 in the state of FIG. Restriction of the upward movement of the substrate 11 is made by the presser bar 12. The presser bar 12 is set after the substrate 11 is placed on the two support bars 18b. As described above, the substrate 11 is stably held in the jig 3 even if the jig 3 rotates by being surrounded and held by the five bars in total.

  The wiper 13 removes the bubbles 16 from the surface of the substrate 11 by the bubble removal surface 13d sweeping around the surface of the substrate 11. As shown in FIG. 4, the wiper 13 has a holding portion 13 a in which a hole 13 b is formed on the upper side, and has a shape such that the bottom portion 13 c on the opposite side of the holding portion 13 a becomes the center of gravity of the wiper 13. .

  The two support bars 18a are connected to each other by a wiper holding bar 17. A plurality of wiper holding rods 17 are arranged at predetermined intervals in the longitudinal direction of the two support rods 18a. A wiper holding portion 17 a is provided at the central portion of the wiper holding rod 17. The wiper holding portion 17a is formed so as to protrude in a direction parallel to the support rod 18, and the positions of the wiper holding portion 17a and the rotation center axis 19 of the jig 3 coincide with each other. That is, the wiper 13 is rotatably held by the wiper holding rod 17 by inserting the wiper holding portion 17a into the hole 13b. Since the center of gravity of the wiper 13 is present on the bottom 13c side, the wiper 13 itself does not rotate with the jig 3 even when the jig 3 rotates, and the bottom 13c is always kept facing downward. . That is, since the wiper 13 is pivotably suspended from the wiper holding portion 17a, the wiper 13 remains in a predetermined position even when the jig 3 holding the substrate 11 is rotationally driven by the motor 9. Further, the bubble removing surface 13 d of the wiper 13 is arranged with a slight gap from the surface of the substrate 11. For this reason, the substrate 11 moves relative to the wiper 13, and the vicinity of the surface of the substrate 11 is swept by the bubble removing surface 13 d of the wiper 13. Further, since the wiper 13 moves relative to the substrate 11, the agitation of the alkaline etching solution 2 in the vicinity of the substrate 11 is promoted. Thereby, the temperature distribution characteristic of the etching solution can be made uniform, and the uniformity of etching can be improved.

  Next, FIG. 5 is a schematic diagram showing a storage state of the substrate 11 in the jig 3. A plurality of wipers 13 are arranged in parallel in the longitudinal direction of the support bar 18 a and the presser bar 12. The substrate 11 is accommodated in the jig 3 so as to correspond to each wiper 13. As the wiper 13 and the surface of the substrate 11 are brought closer to each other, the peeling / removability of the hydrogen bubbles 16 attached to the surface of the substrate 11 is improved.

  Here, the dimensional relationship between the wiper 13, the support bar 18 and the pressing bar 12 will be described. A wiper side surface dimension z is defined as a distance x between the rotation center axis 19 and the presser bar 12 and a distance y between the rotation center axis 19 and the support bar 18 (see FIGS. 3 and 4). In this case, the wiper side surface dimension z of the wiper 13 needs to be shorter than the distances x and y. That is, it is necessary to establish a relationship with z <x, y. This is because when the wiper side surface dimension z is equal to or longer than the distances x and y, when the jig 3 is driven to rotate, the wiper 13 interferes with the rotating support bar 18 and the pressing bar 12. However, the wiper side surface dimension z is preferably as close as possible to the distances x and y which are shorter than the distances x and y. This is because the removal area of the hydrogen bubbles 16 increases, and efficient peeling and removal are possible.

  Next, the etching process by the wet etching apparatus 1 of the present embodiment having the above-described configuration will be described.

  First, as shown in FIG. 1, the plurality of substrates 11 are juxtaposed by being held by four support rods 18. Then, the substrate 11 is accommodated in the jig 3 by bringing the presser bar 12 into contact with the substrate 11 so as to be pressed from the upper surface of the substrate 11.

  Subsequently, as shown in FIGS. 1A and 1B, the jig 3 is set on a support member 7 provided in the processing tank 6. In addition, the alkaline etching liquid 2 in which the temperature is adjusted is circulated in the treatment tank 6.

  The jig 3 in which the substrate 11 is accommodated is completely immersed in the alkaline etching solution 2 in the treatment tank 6. After the immersion, the jig 3 is always rotated at a constant rotational speed by the rotation drive mechanism constituted by the motor 9, the shaft 8, and the rotating gear unit 7. The rotation speed can be adjusted from 2 rotations / minute to 10 rotations / minute. During the rotation operation, as shown in FIG. 1B, the alkaline etching liquid 2 that is always maintained at a constant temperature is continuously supplied along the liquid flow 10 to the main surface of the etching surface of the rotating substrate 11.

  At the same time as the rotation of the jig 3 starts, the stirring action of the alkaline etching solution 2 occurs due to the rotation. By this stirring action, the temperature of the alkaline etching solution 2 supplied to the main surface of the etching surface of the substrate 11 is uniform in temperature distribution, compared with the case where the rotation operation is not performed, and etching with a uniform and constant speed. High quality etching by rate is possible. Further, as described above, since the wiper 13 is relatively moved in the vicinity of the surface of the substrate 11, the alkaline etching solution 2 is agitated. As a result, the temperature distribution is made uniform, and high-quality etching can be performed at a uniform and constant etching rate.

  When the substrate 11 is completely immersed in the alkaline etchant 2, as shown in FIG. 6B from the state of FIG. 6A, an etching groove 15 is formed on the etching surface of the substrate 11, and the etching groove 15 A large amount of hydrogen bubbles 16 are generated simultaneously with the formation of. In FIG. 6, reference numeral 20 denotes a semiconductor element, and reference numeral 14 denotes a protective film.

  In the conventional etching method, as shown in FIG. 8B, a large amount of hydrogen bubbles 16 adhere and stagnate on the surface of the protective film 103, and the etching rate varies.

  However, in the present embodiment, the wiper 13 can effectively remove the bubbles 16 on the surface of the protective film 14. Here, a method of removing bubbles by the wiper 13 will be described with reference to FIG. FIG. 7 is a schematic view of the substrate 11 held in the jig 3 as seen from the normal direction of the main surface of the substrate 11. The jig 3 is shown in FIGS. 7 (a), 7 (b), and FIG. 7 (c) and FIG. 7 (d) rotate clockwise.

  In the state of FIG. 7A, a large amount of bubbles 16 are attached to the surface of the substrate 11. The jig 3 is rotated clockwise from the state of FIG. As a result, the four support bars 18, the presser bar 12, the substrate 11 held by these, and the wiper holding bar 17 rotate integrally in the clockwise direction. On the other hand, the wiper 13 maintains its position without rotating with the bottom 13c facing downward. For this reason, the wiper 13 moves relative to the substrate 11, and the bubbles 16 attached to the surface of the substrate 11 are removed. 7B, FIG. 7C, FIG. 7D, and the jig 3 are rotated clockwise from the state of FIG. 7A, and the wiper 13 causes the entire surface of the substrate 11 to be rotated. The bubbles 16 can be removed. The peeled / removed hydrogen bubbles 16 are carried to the upper surface of the treatment tank 6 along the flow 10 of the alkaline etching solution 2 sprayed from the spray nozzle 5 as shown in FIG. Therefore, the hydrogen bubbles 16 that have been once peeled and removed do not reattach to the surface of the substrate 11. Note that the bubbles on the surface of the substrate 11 include bubbles adhering to the surface of the substrate 11 as well as bubbles adhering to the surface of the substrate 11. That is, the wiper 13 has an effect of preventing the bubbles from adhering in addition to the bubbles already attached to the surface of the substrate 11.

  Moreover, since the wiper 13 of this embodiment is only hung by the wiper holding | maintenance part 17a, the driving force for the removal of the bubble 16 on the surface of the board | substrate 11 is unnecessary. Therefore, the complexity of the apparatus can be avoided and the manufacturing cost of the substrate 11 can be suppressed.

  After the desired etching time has elapsed, the motor 9 is stopped, and the rotation drive mechanism composed of the shaft 8 and the rotation gear unit 7 is stopped. Thereafter, the jig 3 is taken out from the treatment tank 6, and the jig 3 is put into a water washing treatment tank to sufficiently remove the alkaline etching solution 2. After sufficiently removing the alkaline etchant 2, the jig 3 and the substrate 11 accommodated therein are dried. After sufficiently drying, the stored substrate 11 is taken out of the jig 3 and the etching process is finished.

  The shape of the wiper 13 is not limited to that shown in FIG. 4, but various other modifications can be considered, but the shape is not limited thereto. The shape of the wiper 13 is any shape as long as it can move relative to the substrate 11, that is, can stay in a predetermined position without rotating in synchronization with the rotating jig 3. There may be. Further, even when the size of the substrate 11 to be etched is changed, the interference between the wiper 13, the support bar 18, and the pressing bar 12 can be prevented by setting the relationship z <x, y as described above. However, the bubbles 16 can be effectively removed from the surface of the substrate 11.

  As described above, according to the present invention, the wiper 13 provided on the jig 3 can move relative to the rotation of the jig 3 to remove the hydrogen bubbles 16 from the surface of the substrate 11, and the surface of the substrate 11. It is possible to prevent adhesion and stagnation.

  At the same time, according to the present invention, the temperature distribution of the alkaline etching solution 2 around the etching surface can be made uniform by the effect that the alkaline etching solution 2 is stirred by the rotation of the jig 3 and the relative movement of the wiper 13. Thereby, it is possible to perform a high-quality etching process with an etching rate having a uniform and constant speed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a wet etching apparatus block diagram for demonstrating the wet etching method which concerns on one Embodiment of this invention, Fig.1 (a) is a front view, FIG.1 (b) is a side view. It is a block diagram of the jig | tool which concerns on one Embodiment of this invention, Fig.2 (a) is a front view, FIG.2 (b) is a side view. It is a schematic diagram of the cut surface of the jig | tool in the kk part of FIG. It is a schematic diagram of the wiper which concerns on one Embodiment of this invention. It is a schematic diagram which shows the accommodation state of the board | substrate in the jig | tool which concerns on one Embodiment of this invention. It is sectional drawing of the silicon substrate which shows the state before and behind the wet etching which concerns on one Embodiment of this invention. It is a schematic diagram explaining the process of removing the bubble of hydrogen which concerns on one Embodiment of this invention. It is sectional drawing of an example of the silicon substrate which shows the state before and behind the conventional wet etching, and is a figure for demonstrating adhesion of the bubble of hydrogen.

Explanation of symbols

2 Alkali etchant 3 Jig 11 Substrate 13 Wiper 16 Air bubble

Claims (7)

In a jig for wet etching that holds a substrate to be etched by being immersed in an etching solution,
A wet etching jig comprising a wiper that removes bubbles on the surface of the substrate by moving relative to the surface of the substrate held by the jig.   Two side plates, a plurality of bar members that join the two side plates to each other, and hold the substrate so as to be parallel to the main surface of the side plate between the two side plates, and the bar members The wet etching jig according to claim 1, further comprising: a member that couples the members together, wherein the wiper is rotatably held by the member.   3. The jig according to claim 2, wherein the jig is rotatable about a central axis parallel to a longitudinal direction of the bar, and holds the wiper on the member and on the central axis. Jig for wet etching.   The said wiper has the holding | maintenance part currently hold | maintained by the said member, and the bottom part on the opposite side to the said holding | maintenance part, and the gravity center of the said wiper exists in the said bottom part side. Jig for wet etching.   5. The wet etching according to claim 1, wherein the jig holds a plurality of the substrates, and the plurality of wipers are provided corresponding to each of the substrates to be held. 6. Jigs.   The wet etching according to any one of claims 1 to 5, wherein the wiper is provided so that a surface of the wiper for removing the bubbles is parallel to a main surface of the substrate. Jigs. A wet etching apparatus comprising the wet etching jig according to any one of claims 1 to 5,
The jig includes two side plates and a plurality of bar members that join the two side plates and hold the substrate so as to be parallel to the main surface of the side plate,
A treatment tank containing a wet etching solution and the jig;
A wet etching apparatus comprising: drive means for driving the jig to rotate at a constant number of rotations about a central axis parallel to the longitudinal direction of the bar.

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