JP4182841B2 - Single crystal substrate processing method - Google Patents

Description

  The present invention relates to a method of forming minute through holes or non-through holes in a substrate made of a material made of a single crystal.

  Conventionally, after forming a non-through hole from one side of a silicon single crystal substrate, anisotropic etching is performed to form a through hole with a high aspect ratio without being affected by the crystal orientation of silicon ( For example, see Patent Document 1).

JP-A-10-166600

  However, in the conventional technique, when the through hole or the non-through hole is formed using the laser beam, the laser beam is absorbed by energy absorption at the hole wall surface as the through hole or the non-through hole becomes deeper. Since energy loss becomes large, it is necessary to input a larger power. As a result of applying a large amount of power, the edge portion of the opening is damaged, it is difficult to form the edge portion with high accuracy, and there are unsolved problems such as a limit to further miniaturization.

  The present invention has been made in order to solve the above-described problems. A single crystal substrate for forming fine and high aspect ratio through-holes or non-through-holes on a substrate made of a material made of a single crystal. An object is to provide a processing method.

  In order to solve the above problems, the present invention provides a processing method for forming a non-through hole or a through hole in a predetermined path in a substrate made of a material made of a single crystal, and irradiating the substrate with laser light. A laser beam irradiation step of forming a material-modified part by modifying the material along the predetermined path, and etching the material-modified part to form the non-through hole or the through-hole in the predetermined path. And an anisotropic etching step to be formed.

  Here, the material altered portion means that by irradiating a laser beam, a bond between some atoms in a single crystal is broken, an infinite number of minute cracks are generated, or crystallinity is destroyed. This is the part where the material has been altered.

  According to the above, in the laser light irradiation step, only the material-modified portion is formed on the single crystal substrate, and no damage that hinders formation of a desired through-hole or non-through-hole is caused.

  In the present invention, in the laser beam irradiation step, the material-modified part is formed so that the end of the material-modified part is at a predetermined position within the thickness of the substrate.

  According to the above, in the laser light irradiation step, the material-modified portion is formed so that the end portion of the material-modified portion is at a predetermined position within the thickness of the substrate, and thus the material-modified portion is not formed on the substrate surface. . Therefore, the substrate surface is not damaged by the laser beam irradiation.

  The present invention further includes an etching mask film forming step of forming an etching mask film having a pattern-shaped hole corresponding to the shape of the non-through hole or the opening of the through hole, and the predetermined position is It is characterized in that it is in a region surrounded by a region exposed from the pattern-shaped hole in the surface of the substrate and a crystal surface having a low etching rate that appears by etching the region.

  Note that the order of the etching mask film forming step and the laser light irradiation step is not limited, and either may be first. This increases the degree of freedom in selecting the order of the etching mask film forming process and the laser light irradiation process.

  According to the above, in the laser light irradiation step, the material-modified portion is formed so that the end portion of the material-modified portion is at a predetermined position within the thickness of the substrate. The altered part is not formed. Accordingly, since damage to the substrate surface due to the laser beam irradiation does not occur, when the laser beam is irradiated after the etching mask film is formed, the etching mask film is not damaged, and the substrate surface, the etching mask film, It is possible to maintain stable adhesion during the period. In the case where an etching mask film is formed after the laser light irradiation step, the substrate surface is not damaged and the flatness is maintained, so that an etching mask film having a fine pattern shape can be formed.

  Also, in the anisotropic etching process, etching is performed on the material-modified portion before the area exposed from the pattern-shaped hole on the surface of the substrate is etched and the progress of the etching is prevented by the crystal surface having a low etching rate. Can be reached.

  In the present invention, the substrate is made of a material made of silicon single crystal, and in the laser light irradiation step, infrared laser light is condensed onto the substrate by a condensing element and irradiated. .

  According to the above, it is possible to form the material-modified part by condensing the infrared laser beam with the condensing element and irradiating the substrate made of the material made of silicon single crystal.

In the present invention, in the laser light irradiation step, the substrate is irradiated with a fundamental wavelength light of a YAG laser, a YVO ₄ laser, or a YLF laser.

  In the present invention, the laser beam irradiation step irradiates a Bessel beam generated by a Bessel beam generation optical system.

  In the present invention, in the laser beam irradiation step, a plurality of laser beams having different divergence angles are condensed by a condensing element and irradiated.

  In the present invention, in the laser beam irradiation step, the laser beam is split into a plurality of beams and irradiated by a diffractive optical element.

  In the present invention, in the laser beam irradiation step, the energy of the laser beam is controlled in accordance with the depth of the material altered portion.

  In the present invention, the laser light irradiation step irradiates the laser light while moving the substrate relative to the light source of the laser light.

  The best mode for carrying out the present invention will be described with reference to the drawings.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic cross-sectional view showing each step of the method for processing a single crystal substrate according to the first embodiment.

  As shown in FIG. 1E, the first embodiment is a processing method for forming a through hole 2 in a substrate 1 having a plane orientation (110) made of a material made of silicon single crystal.

First, in the etching mask film forming step, as shown in FIG. 1A, an etching mask film 3 made of SiO ₂ is formed on the surface of a substrate 1 having a plane orientation (110) made of a material made of silicon single crystal. The pattern-shaped holes 4 a and 4 b corresponding to the shape of the opening of the through hole 2 are formed on the front and back surfaces of the substrate 1.

  The etching mask film 3 can be formed by the following method.

First, a SiO ₂ film is formed by a thermal oxidation method, a resist is applied thereon by a spin coating method, and a resist pattern for forming pattern-shaped holes 4a and 4b is formed by using a photolithography technique.

Thereafter, the SiO ₂ film is removed in accordance with the resist pattern shape using a hydrofluoric acid solution or the like, and the unnecessary resist pattern is peeled off to form the etching mask film 3. Note that the etching mask film is not limited to SiO ₂ and may be a film made of a material having corrosion resistance against an anisotropic etching solution such as a silicon nitride film or a metal film.

Next, in the laser light irradiation step, as shown in FIG. 1B, the fundamental wavelength light 5 of the YAG laser, YVO ₄ laser, or YLF laser is condensed by the lens 6, and the condensing point is the plate of the substrate 1. The formation of the material altered portion 7 is started by irradiating the laser beam so as to coincide with the predetermined position P1 within the thickness. Note that the laser light of the YAG laser, YVO ₄ laser, or YLF laser is infrared laser light that is transmissive to a substrate formed of a material made of silicon single crystal.

  Then, as shown in FIG. 1 (c), the material altered portion 7 (shown in black in the figure) is gradually formed while the condensing point is moved along the path 8 that forms the through hole 2. Then, the laser beam irradiation process is completed (FIG. 1D). In the embodiment of the present invention, energy loss of the laser beam occurs due to the absorption of the laser beam by the material of the single crystal substrate. Therefore, control is performed so that the energy of the laser beam is increased according to the depth of the material altered portion 7. However, it is preferable to perform laser light irradiation.

  Next, in the anisotropic etching step, the substrate 1 is immersed in an aqueous solution of potassium hydroxide, and etching proceeds according to the pattern-shaped holes 4a and 4b of the etching mask film 3 as shown in FIG. By doing so, the through hole 2 is formed.

  Here, the predetermined position P1 will be described.

  FIG. 2 is a diagram showing details of the K portion in FIG. As shown in the figure, in the substrate 1 with the plane orientation (110), when the region 11a exposed by the pattern-shaped hole 4a on the surface of the substrate 1 is anisotropically etched, the pattern-shaped hole 4a (111) planes 14a and 14b, which are crystal planes, appear from intersections 12a and 12b of the substrate 1 and the surface of the substrate 1 in a direction facing each other at a predetermined angle with the surface of the substrate 1. These (111) surfaces 14a and 14b have extremely low etching rates, and anisotropic etching stops when these (111) surfaces 14a and 14b appear.

  The predetermined position P1 in the laser beam irradiation process according to the present embodiment is an arbitrary region in the region 11a exposed by the pattern-shaped hole 4a on the surface of the substrate 1 and the region surrounded by the (111) surfaces 14a and 14b. Position. That is, in the laser light irradiation process, the material-modified part 7 is formed so that one end 7a of the material-modified part 7 is located in the region. The vertical depth from the region 11a exposed by the pattern-shaped hole 4a on the surface of the substrate 1 at the position P1 is shallower than the vertical depth from the region 11a at the intersection of the surface 14a and the surface 14b. .

  FIG. 3 is a diagram showing details of the position of the other end 7 b of the material-affected portion 7. As shown in FIG. 3, the other end portion 7b of the material-affected portion 7 is also similar to the above in the region 11b exposed by the pattern-shaped hole 4b on the surface of the substrate 1 and the (111) surfaces 15a and 15b. The material altered portion 7 is formed so as to be located within the enclosed region.

  A description will be given of how the substrate 1 on which the material alteration portion 7 is formed proceeds in the anisotropic etching step with reference to FIG.

  FIG. 4 is a schematic cross-sectional view showing the anisotropic etching process according to the present embodiment.

  As shown in FIG. 4A, in the initial stage of etching, the regions 11a and 11b exposed by the pattern-shaped holes 4a and 4b on the front surface and the back surface of the substrate 1 become (111) surfaces 14a and 14b and 15a. And 15b. The (111) planes 14a, 14b, 15a and 15b correspond to crystal planes with a low etching rate.

  Subsequently, when the etching reaches the material-affected portion 7, as shown in FIG. 4B, the material-affected portion 7 that is susceptible to etching is etched first, and an etching guide hole 20 that becomes a hole that guides the progress of etching is formed. It is formed.

  Here, the material altered portion 7 is that when a silicon single crystal is irradiated with laser light, the bonds of atoms in the single crystal are cut, microcracks are generated, or the crystallinity is destroyed. Since the etching rate of the material-modified part 7 is much higher than that of the unmodified material region, the above-described etching guide hole 20 can be formed.

  As the etching from the etching guide hole 20 progresses, as shown in FIG. 4C, substantially vertical surfaces 21 and 22 appear on the substrate 1 made of the (111) surface, and these surfaces 21 and 22 appear. Etching is stopped at a continuous stage, and the through-holes 2 that coincide with the pattern-shaped holes 4a and 4b are formed (FIG. 4D).

  That is, according to the method for processing a single crystal substrate according to the first embodiment, the etching of the material-affected zone 7 is stopped before reaching the (111) planes 14a and 14b and 15a and 15b and stopping. The end portions 7a and 7b can be reached, and etching can proceed along the material-affected portion 7 to form the through hole 2 thereafter.

  Further, the reason why the end portion 7a of the material altered portion 7 does not reach the surface of the substrate 1 is to prevent damage due to formation of the material altered portion 7 on the surface.

  As described above, the end portion 7a of the material-affected portion 7 does not reach the surface, but as described above, the region 11a exposed by the pattern-shaped hole 4a on the surface of the substrate 1 and the (111) surfaces 14a and 14b. If it is located within the region surrounded by, etching can reach the material-affected portion 7 and the through hole 2 can be formed.

  As described above, in the laser light irradiation process, the material-affected portion 7 can be formed so that the surface of the substrate 1 is not damaged. Therefore, even if the fine etching mask film 3 is formed, the pattern shape is fine. The holes 4a and 4b are not damaged in the subsequent laser light irradiation process. Therefore, it is possible to form the through hole 2 having a high aspect ratio.

  In the first embodiment, in the laser beam irradiation step, the laser beam is irradiated so that the condensing point of the laser beam 5 by the lens 6 coincides with the predetermined position P1 within the plate thickness of the substrate 1. Although the formation of the material altered portion 7 is started, the present invention is not limited to this. In other words, if the end portion 7a of the material altered portion 7 of the substrate 1 that has undergone the laser light irradiation step coincides with the predetermined position P1, laser light irradiation is performed from any location on the path of the through hole 2. You may start.

  In the first embodiment, the etching mask film forming step is included, but the etching mask film forming step is not necessarily required. If high accuracy is not required for the shape of the opening of the through hole 2 and the surface roughness of the substrate 1, the through hole can be formed by etching without forming the etching mask film 3.

  As a modification of the laser beam focusing method in the laser beam irradiation step, FIG. 5 shows an example of laser beam irradiation with a Bessel beam generating optical system, and FIG. 6 shows a plurality of laser beams having different divergence angles. FIG. 7 shows an example in which laser light is condensed and irradiated by a condensing element, and FIG.

  According to these modified examples, it is possible to shorten the time required for forming the material altered portion 7 in the laser light irradiation step, and it is possible to improve the processing efficiency.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIG.

  In the second embodiment, only parts different from the first embodiment will be described.

  FIG. 8 is a schematic cross-sectional view showing each step of the method for processing a single crystal substrate according to the second embodiment.

  As shown in FIG. 8E, the second embodiment is a processing method for forming a non-through hole 35 having a depth d1 in a substrate 1 having a plane orientation (110) made of a material made of silicon single crystal. is there.

First, in the etching mask film forming step, as shown in FIG. 8A, an etching mask film 3 made of SiO ₂ is formed on the surface of the substrate 1 having a plane orientation (110) made of a material made of silicon single crystal. The hole 36 having a pattern shape corresponding to the shape of the opening of the non-through hole 35 is formed only in one surface 31 of the substrate 1 by the same method as in the first embodiment. Note that the etching mask film is not limited to SiO ₂ and may be a film made of a material having corrosion resistance against an anisotropic etching solution such as a silicon nitride film or a metal film.

  Next, in the laser beam irradiation step, as shown in FIG. 8B, the formation of the material-affected portion 7 is started by irradiating the laser beam similarly to the step in the first embodiment.

  Then, as shown in FIG. 8C, the material altered portion 7 is gradually formed while the focal point is moved to the depth d1 along the path 37 that forms the non-through hole 35, and the laser is formed. The light irradiation process is completed (FIG. 8D).

  Next, in the anisotropic etching step, as shown in FIG. 8E, the substrate 1 is etched to form a non-through hole 35 having a depth d1, as in the step in the first embodiment.

  Here, the progress of anisotropic etching at the predetermined position P1 and the material altered portion 7 is basically the same as in the first embodiment although there is a difference between the non-through hole and the through hole. Is omitted.

  As described above, in the laser light irradiation process, the material-affected portion 7 can be formed so that the surface of the substrate 1 is not damaged. Therefore, even if the fine etching mask film 3 is formed, the pattern shape is fine. The hole 36 is not damaged in the subsequent laser light irradiation process. Accordingly, it is possible to form the non-through hole 35 having a high aspect ratio. In addition, the depth of the material altered portion 7 can be easily controlled by controlling the position of the condensing point in the substrate 1 in the laser light irradiation step, and the depth of the non-through hole 35 in anisotropic etching. Can be controlled easily. Therefore, variation in the depth of the non-through hole 35 for each single crystal substrate can be easily controlled.

  In the second embodiment, in the laser beam irradiation step, the laser beam is irradiated so that the condensing point of the laser beam 5 by the lens 6 coincides with a predetermined position P1 within the plate thickness of the substrate 1. Although the formation of the altered portion 7 is started, the present invention is not limited to this. In other words, if the end portion 7a of the material altered portion 7 of the substrate 1 that has undergone the laser beam irradiation step coincides with the predetermined position P1, laser beam irradiation is performed from any location on the path of the non-through hole 35. You may start.

  In the second embodiment, the laser beam is irradiated from the surface side having the pattern-shaped hole 36. However, the present invention is not limited to this, and the surface side not having the pattern-shaped hole 36 is used. You may make it irradiate from.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIG.

  In the third embodiment, only parts different from the first and second embodiments will be described.

  FIG. 9 is a schematic cross-sectional view showing each step of the method for processing a single crystal substrate according to the third embodiment.

  As shown in FIG. 9E, the third embodiment is a processing method in which a through hole 41 is formed in a desired path in a substrate 1 having a plane orientation (110) made of a material made of silicon single crystal. is there.

First, in the etching mask film forming step, as shown in FIG. 9A, an etching mask film 3 made of SiO ₂ is formed on the surface of the substrate 1 having a plane orientation (110) made of a material made of silicon single crystal. The first surface 31 of the substrate 1 has a pattern-shaped hole 44 corresponding to the shape of the one opening 42 of the through hole 41 and a pattern-shaped hole 45 corresponding to the shape of the other opening 43. It is formed by the same method as in the first embodiment. Note that the etching mask film is not limited to SiO ₂ and may be a film made of a material having corrosion resistance against an anisotropic etching solution such as a silicon nitride film or a metal film.

  Next, in the laser beam irradiation step, as shown in FIG. 9B, the formation of the material altered portion 7 is started by irradiating the laser beam in the same manner as in the first or second embodiment.

  Then, as shown in FIG. 9 (c), the material alteration part 7 is gradually formed while moving the condensing point along the path 46 that forms the through hole 41, and the laser light irradiation process is completed. (FIG. 9D).

  Next, in the anisotropic etching step, as shown in FIG. 9E, the substrate 1 is etched to form a through hole 41 having a desired path, as in the step in the first or second embodiment. Form.

  Here, the progress of the anisotropic etching at the predetermined position P1 and the material altered portion 7 is basically the same as that of the first embodiment although the path for anisotropic etching is different, and the description thereof is omitted. To do.

  As described above, in the laser light irradiation step, the material-modified portion can be formed so that the surface of the substrate 1 is not damaged. Therefore, even if the fine etching mask film 3 is formed, the pattern-shaped hole 44 and 45 is not damaged in the subsequent laser light irradiation process. Therefore, the through hole 41 having a high aspect ratio can be formed in a desired path.

  In the third embodiment, the case where the through hole 41 is formed so that the one opening 42 and the other opening 43 are on the one surface 31 of the substrate 1 has been described as an example. However, the third embodiment is not limited thereto. It is not something. The present invention can also be applied to the case where the through hole 41 is formed such that one opening 42 is on one surface 31 of the substrate 1 and the other opening 43 is on the other surface of the substrate 1.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIG.

  In the fourth embodiment, only parts different from the first, second, and third embodiments will be described.

  FIG. 10 is a schematic cross-sectional view showing each step of the method for processing a single crystal substrate according to the fourth embodiment.

  As shown in FIG. 10E, in the fourth embodiment, a processing method of forming a non-through hole 51 in a desired path in a substrate 1 having a plane orientation (110) made of a material made of silicon single crystal. It is.

First, in the etching mask film forming step, as shown in FIG. 10A, an etching mask film 3 made of SiO _{2 is not applied} to a substrate 1 having a plane orientation (110) made of a material made of silicon single crystal. A pattern-shaped hole 53 corresponding to the shape of the opening 52 of the through hole 51 is formed on the one surface 31 of the substrate 1 by the same method as in the first embodiment. Note that the etching mask film is not limited to SiO ₂ and may be a film made of a material having corrosion resistance against an anisotropic etching solution such as a silicon nitride film or a metal film.

  Next, in the laser beam irradiation step, as shown in FIG. 10B, the formation of the material-affected portion 7 is started by irradiating the laser beam in the same manner as in the steps in the first to third embodiments.

  Then, as shown in FIG. 10C, the material alteration portion 7 is gradually formed while moving the condensing point along the path 54 that forms the non-through hole 51, and the laser light irradiation step is performed. The process ends (FIG. 10 (d)).

  Next, in the anisotropic etching step, as shown in FIG. 10E, the substrate 1 is etched to form the non-through holes 51 having a desired path, as in the steps in the first to third embodiments. Form.

  Here, the progress of anisotropic etching at the predetermined position P1 and the material-affected portion 7 is basically the same as that of the first embodiment, and the description thereof is omitted.

  As described above, in the laser light irradiation step, the material-modified portion can be formed so that the surface of the substrate 1 is not damaged. Therefore, even if the fine etching mask film 3 is formed, fine holes having a pattern shape are formed. 53 is not damaged in the subsequent laser light irradiation process. Therefore, it is possible to form the high aspect ratio non-through hole 51 in a desired path.

  In the third and fourth embodiments, in the laser light irradiation step, the laser light is emitted so that the condensing point of the laser light 5 by the lens 6 coincides with a predetermined position P1 within the plate thickness of the substrate 1. Irradiation is performed to start the formation of the material altered portion 7, but the present invention is not limited to this. That is, from any location on the path of the through hole 41 or the non-through hole 51 as long as the end portion 7a of the material altered portion 7 of the substrate 1 that has undergone the laser light irradiation process coincides with the predetermined position P1. However, laser beam irradiation may be started.

  In the third and fourth embodiments, the laser light is irradiated from the surface side having the pattern-shaped holes 44, 45, and 53, but the surface that does not have the pattern-shaped holes 44, 45, and 53. You may make it irradiate from the side.

  In the third and fourth embodiments, the case where the paths 46 and 54 of the through hole 41 and the non-through hole 51 are in the vertical direction and the horizontal direction with respect to the surface of the substrate 1 has been described as an example. It is not limited. FIG. 11 shows a modified example of the path of the through hole or the non-through hole. For example, as shown in FIG. 11A, the path 58 may be inclined with respect to the surface of the substrate 1, and FIG. As shown in (b), it is also applicable to a curved path 59.

  Moreover, the example of FIG.5, FIG.6 or FIG.7 which is a modification of the condensing method of the laser beam in a laser beam irradiation process can be applied to any of 2nd-4th embodiment, According to these modified examples, in any of the second to fourth embodiments, it is possible to shorten the time required for forming the material altered portion in the laser light irradiation step, and to improve the processing efficiency. Become.

In the first to fourth embodiments, the fundamental wavelength light of the YAG laser, YVO ₄ laser, or YLF laser is used as the light source in the laser light irradiation step. However, if the laser light has a wavelength in the infrared region, It is not limited to these.

  In the first to fourth embodiments, the processing method for forming a through hole or a non-through hole in a substrate having a plane orientation (110) made of a material made of a silicon single crystal has been described. However, the present invention is not limited thereto. It is not something. For example, the present invention can be applied to a substrate having a plane orientation (100) made of a material made of silicon single crystal. That is, the present invention can be applied to a plane orientation in which a crystal plane with a low etching rate occurs as an obstacle to the intended processing, and can be applied to a material other than silicon as long as it is made of a single crystal. Is something that can be done.

  In the first to fourth embodiments, the lens 6 corresponds to a condensing element.

  In the first to fourth embodiments, a processing method for forming a through hole or a non-through hole in one single crystal substrate has been described. However, a plurality of single crystal substrates are overlapped with each other and irradiated with laser light. It may be.

  FIG. 12 is a diagram illustrating an example in which a plurality of single crystal substrates are stacked and irradiated with laser light.

  As shown in FIG. 12, the case where the first single crystal substrate 61 and the second single crystal substrate 62 are irradiated with laser light after forming the etching mask film 3 on the surface of each single crystal substrate is described. To do.

  After the first material altered portion 63 is formed in the first single crystal substrate 61 by a predetermined path, the second material altered portion is continuously formed along the predetermined path 64 in the second single crystal substrate 62. 65 is formed.

  FIG. 13 is a diagram illustrating another example in which a plurality of single crystal substrates are stacked and irradiated with laser light.

  As shown in FIG. 13, after forming the first material altered portion 69 of the first single crystal substrate 67, the second material is then moved along a predetermined path 70 inside the second single crystal substrate 68. The altered portion 71 is formed, and subsequently, a third material altered portion (not shown) is formed along the second path 72 of the first single crystal substrate 67.

  According to the example in which a plurality of single crystal substrates are overlapped with each other and irradiated with laser light as described above, the time required for rearrangement of the single crystal substrates in the laser light irradiation step can be reduced, and the plurality of single crystals can be reduced. The projection area of the apparatus that irradiates the laser beam can be made smaller than when the substrates are processed on the same plane.

  According to said 1st-4th embodiment and those modifications, a several single crystal board | substrate is moved relatively with respect to the light source of a laser beam with conveyance apparatuses, such as a conveyance table, a belt conveyor, and a transfer machine. However, it is possible to configure the flow processing for performing laser light irradiation, and further improve the processing efficiency. In this case, the relative movement of the single crystal substrate with respect to the light source of the single crystal substrate may be any one of a plane movement, a vertical movement, or a combination movement of the plane movement and the vertical movement, and the movement may be a continuous movement or an intermittent movement. Either is acceptable. In particular, the continuous movement is preferable in terms of improvement in processing efficiency due to the characteristics of laser light.

  In this invention, it is not limited to forming a material alteration part along the centerline of a through-hole or a non-through-hole. A route deviating from the center line may be used as long as it is a predetermined route passing through the cross section of the through hole or the non-through hole. As described above, the through hole or the non-through hole can be formed in a desired path determined from the hole of the etching mask film 3 even if it is off the center line of the through hole or the non-through hole.

The technical idea grasped from the embodiment and the modified examples will be described below.
(1) A processing method for forming a non-through hole or a through hole in a predetermined path on a substrate made of a material made of a single crystal, and irradiating the substrate with laser light along the predetermined path A laser beam irradiation step of altering the material to form a material alteration portion; an anisotropic etching step of etching the material alteration portion to form the non-through hole or the through hole in the predetermined path; In the laser light irradiation step, the material-modified portion is formed so that the end portion of the material-modified portion is located at a predetermined depth from one surface or the other surface of the substrate. And

  As described above, when forming a through hole or non-through hole having a fine and high aspect ratio in a desired path, the desired through hole or non-through hole is formed on the surface of the substrate made of a material made of a single crystal. However, it is possible to prevent the occurrence of damage that is an obstacle.

The schematic cross section which shows each process of the processing method of the single crystal substrate which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the detailed position of the edge part of a material alteration part. Sectional drawing which shows the detailed position of the other edge part of a material alteration part. The schematic cross section which shows the anisotropic etching process process which concerns on embodiment of this invention. FIG. 3 is a schematic cross-sectional view showing an example of laser beam irradiation with a Bessel beam by a Bessel beam generation optical system. The schematic cross section which shows the example which condenses and irradiates the several laser beam from which a divergence angle differs with a condensing element. FIG. 3 is a schematic cross-sectional view showing an example in which laser light is split into a plurality of beams by a diffractive optical element and irradiated at multiple points simultaneously. The schematic cross section which shows each process of the processing method of the single crystal substrate which concerns on the 2nd Embodiment of this invention. The schematic cross section which shows each process of the processing method of the single crystal substrate which concerns on the 3rd Embodiment of this invention. The schematic cross section which shows each process of the processing method of the single crystal substrate which concerns on the 4th Embodiment of this invention. The schematic cross section which shows the modification of the path | route of a through-hole or a non-through-hole. FIG. 6 is a schematic cross-sectional view illustrating an example in which a plurality of single crystal substrates are stacked and irradiated with laser light. FIG. 6 is a schematic cross-sectional view illustrating another example in which a plurality of single crystal substrates are stacked and irradiated with laser light.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Substrate 3 ... Etching mask film 5 ... Laser beam 7 ... Material alteration part 2, 41 ... Through-hole 35, 51 ... Non-through-hole 8, 37, 46, 54, 58, 59 ... Path | route 4a, 4b, 36, 44 , 45, 53... Pattern-shaped holes 14a, 14b, 15a, 15b... (111) plane as a crystal plane with a slow etching rate

Claims (8)

A processing method of forming a non-through hole or a through hole in a predetermined path on a substrate made of a material made of a single crystal,
An etching mask film forming step of forming, on the substrate, an etching mask film having a pattern-shaped hole corresponding to the shape of the non-through hole or the opening of the through hole;
A laser beam irradiation step of irradiating the substrate with a laser beam to alter the material along the predetermined path to form a material altered portion;
And anisotropically etching the material altered portions, have a, an anisotropic etching process for forming the non-through hole or the through hole in the predetermined path,
In the laser light irradiation step, etching is performed on a range in which an end portion of the material-modified portion is located at a predetermined depth from one surface of the substrate and exposed from the hole of the etching mask film. The material altered portion is formed so as to be located in a region surrounded by a crystal plane having a low etching rate that appears due to the above . In the etching mask film forming step, the etching mask film is formed on the front surface and the back surface of the substrate,
In the laser light irradiation step, etching is performed on a range in which one end portion of the material-modified portion is located at a predetermined depth from the surface of the substrate and is exposed from the hole of the etching mask film. And the other end portion of the material-affected portion is located at a predetermined depth from the back surface of the substrate, and the etching mask film has the other end portion. The material-altered portion is formed so as to be located in a region surrounded by a range exposed from the hole and a crystal plane having a low etching rate that appears by etching the range. A method for processing a single crystal substrate as described in 1. above. The substrate is made of a material made of silicon single crystal,
3. The method for processing a single crystal substrate according to claim 1, wherein in the laser light irradiation step, the substrate is irradiated with infrared laser light condensed by a condensing element. 4. In the laser beam irradiation step, the infrared laser beam is irradiated so that the condensing point of the infrared laser beam is moved in the thickness direction of the substrate and then moved in the lateral direction inside the substrate. The method for processing a single crystal substrate according to claim 3 , wherein: In the etching mask film forming step, an etching mask film having the holes at different positions on the substrate is formed,
In the laser beam irradiation step, the condensing point of the infrared laser beam is moved in the plate thickness direction of the substrate, and a position corresponding to a position below one of the holes at the different position is below the other hole. 5. The single crystal substrate processing according to claim 4 , wherein the infrared laser light is irradiated so that the substrate is moved laterally within the substrate until the substrate is moved in the plate thickness direction of the substrate. Method. Wherein the laser beam irradiation step, the processing method of the single crystal substrate according to any one of claims 1 to 5, characterized in that to control the energy of the laser light according to the depth of the material altered portions. The single crystal according to any one of claims 1 to 6 , wherein, in the laser light irradiation step, the laser light is irradiated while the substrate is moved relative to the light source of the laser light. Substrate processing method. In the laser beam irradiation step, single crystal according to any one of claims 1 to 7, characterized in that the irradiating the laser beam the etching mask film in a state of overlapping a plurality of said substrate formed respectively Substrate processing method.

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