JP3893077B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a semiconductor device, in particular, a semiconductor device and a manufacturing method thereof.
[0002]
[Prior art]
  Conventionally, micromachine technology using a semiconductor material such as silicon has been provided. Examples of devices using this micromachine technology include various sensors, microactuators, fluid control devices such as micropumps and valves. In such a device, a three-dimensional structure is generally formed on the surface of a semiconductor substrate using an insulating film or a metal pattern.
[0003]
[Problems to be solved by the invention]
  FIG. 10 is an explanatory diagram showing the structure of the micropump and its operating principle. (A) is an explanatory view showing a micro pump in the discharge mode, (b) is an explanatory view showing the micro pump in the discharge mode, (c) is a plan view of valves, inlets and outlets of the micro pump, FIG. 4D is an enlarged view of the valve. The micropump includes a heat-resistant glass plate 61 on which a partition plate 62 is formed, a silicon substrate 71 on which valves 72 a and 72 b and through holes 73 a, 73 b, 73 c and 73 d (through holes 73) are formed, and a heat-resistant glass plate 61. And a heat-resistant glass plate 81 bonded to the opposite silicon substrate surface. On the partition plate 62 of the heat-resistant glass plate 61, a piezo actuator 63 for vibrating the partition plate 62 is attached. The valves 72a and 72b support a disc-shaped valve made of polysilicon having a shape that blocks the liquid path on a silicon substrate 71 having a through hole 73 serving as a liquid path, and one side fixed to the substrate to support the valve. It is formed from four arms (see FIGS. 10C and 10D).
[0004]
  The micro pump having such a structure operates by applying a voltage to the piezo actuator 63. The piezoelectric actuator 63 to which the voltage is applied pushes down the partition plate 62. As a result, the pressure in the pressure chamber 66 is increased, the valve 72a on the inlet 64 side is closed, the valve 72b on the outlet 65 side is opened, and liquid is discharged therefrom (see FIG. 10A). When the voltage is turned off, the partition plate 62 tries to return. As a result, the pressure in the pressure chamber 66 is lowered, the valve 72b on the outlet 65 side is closed, the valve 72a on the inlet 64 side is opened, and new liquid is sucked into the pressure chamber 66 (see FIG. 10B).
[0005]
  By the way, in such a micropump manufacturing process, after the valves 72 a and 72 b are formed on the silicon substrate 71, the through holes 73 b and 73 d are formed so as to be accurately positioned with respect to the valve 72. Further, the through holes 73a and 73c are formed so that the liquid inlet 64 and the outlet 65 of the liquid formed on the heat-resistant glass plate 61 are precisely positioned. The through-hole 73 is formed by forming a mask on both surfaces of the silicon substrate 71 and anisotropically etching the silicon substrate 71 from the front surface and the back surface.
[0006]
  However, the thickness of a semiconductor substrate such as silicon is about 625 μm for a 6-inch wafer substrate, for example, and the etching depth is deep. For this reason, the direction in which etching proceeds is shifted until the through-hole to be formed penetrates the front and back surfaces of the semiconductor substrate, and it is difficult to reach the through-hole at the target position on the front surface. As the cause, for example, the following can be considered.
[0007]
  1) Although alignment between the position of the front surface through which the through-hole should penetrate and the etching start position on the back surface is performed by image processing, it is difficult to obtain alignment accuracy due to a shift in image processing.
  2) Due to lattice defects existing in the semiconductor substrate, a shift occurs in the etching traveling direction, and the opening position of the surface shifts from the target position.
[0008]
  3) Etching varies greatly in etching speed due to temperature and humidity, and when batch processing or the like is performed, it is difficult to suppress variations in etching speed and side etching amount between wafers or in the wafer surface.
  For this reason, in forming the through hole, the design must have a margin in the position and size of the opening on the surface of the semiconductor substrate, and the semiconductor device becomes large and the manufacturing cost increases. Specifically, even when it is desired to form a through hole having a width of about 20 μm on the surface of a substrate using a 6-inch silicon substrate, an opening space of about 100 μm is expected at the manufacturing stage.
[0009]
  An object of the present invention is to accurately form a through hole in one surface of a semiconductor substrate from the other surface.
  Another object of the present invention is to manufacture and provide a high-density semiconductor device by forming a through hole having an opening of a necessary and sufficient size on one surface of the semiconductor substrate from the other surface.
[0010]
  Still another object of the present invention is to manufacture a semiconductor device having a stable quality by stably forming a through hole regardless of a wafer or a manufacturing process.
[0011]
[Means for Solving the Problems]
  The method for manufacturing a semiconductor device according to the first aspect includes the following steps.
A guide forming step of forming a first guide portion that is a groove-like or hole-like space on the first surface of the semiconductor substrate.
・A defect introduction step of introducing lattice defects into the semiconductor substrate around the first guide portion;
A through hole forming step of etching the semiconductor substrate from the second surface side of the semiconductor substrate opposite to the first surface toward the first guide portion to form a through hole penetrating the semiconductor substrate;
[0012]
  A narrow hole, for example, a groove having a width of 1 μm is formed on the surface (first surface) of the semiconductor substrate. Preferably, lattice defects are further introduced around the narrow groove, and then a through hole is formed by etching from the back surface of the substrate. At that stage, etching is induced in a portion where a lattice defect is generated around the groove. Therefore, the etching proceeds rapidly using the narrow groove as a guide, and a through hole having an opening having a width substantially equal to the groove width on the substrate surface is formed. In the semiconductor device thus formed, through holes having a desired width are formed at desired positions on the substrate surface, so that functional parts such as integrated circuits can be mounted on the substrate surface with high density. . The width of the through hole can be adjusted to a desired width by further etching as necessary. Therefore, it is not necessary to provide a margin for the position and size deviation when forming the through hole, and a semiconductor chip with high density and good yield can be manufactured.
[0013]
  In this method, etching proceeds along the first guide portion due to lattice defects introduced around the first guide portion. Therefore, a through hole having an opening width of about 1 μm, for example, about the width of the first guide portion can be formed by etching from the second surface side at a target position on the first surface.
  The method for manufacturing a semiconductor device according to the second aspect further includes a surface film forming step. In the surface film forming step, a surface film covering at least the first guide portion is formed on the first surface.
[0014]
  In this method, a surface film covering the narrow groove is formed. An integrated circuit or the like may be formed on the surface film. The surface film penetrating into the opening portion or inside of the through hole can be removed by etching in the through hole forming step or by etching independent of the etching.
  According to a third aspect of the present invention, there is provided a semiconductor device manufacturing method according to the first or second aspect, wherein the semiconductor substrate is a silicon substrate, and the surface film is formed of a silicon oxide film or polysilicon in the surface film forming step.
[0015]
  In particular, since polysilicon can be etched at a higher speed than silicon, there is an advantage that the opening position of the through hole in the first surface can be easily controlled.
  The method for manufacturing a semiconductor device according to a fourth aspect of the present invention is the method of the first or second aspect, wherein the surface film is formed by CVD (Chemical Vapor Deposition) in the surface film forming step.
[0016]
  When the surface film is formed by CVD, for example, plasma CVD, it is difficult for the surface film to enter the narrow groove of the substrate formed in the portion that becomes the through hole. For this reason, only the opening portion of the first guide portion is covered with the surface film, the back of the first guide portion is hollow, and unnecessary portions of the surface film are removed as compared with the case where all the grooves are filled with the surface film. Is easy.
  In the semiconductor device manufacturing method according to a fifth aspect of the present invention, in any one of the first to fourth aspects, the through-hole forming step includes the following steps.
A primary etching step of forming a through hole up to the tip of the first guide part by anisotropic etching or isotropic etching.
A secondary etching step of penetrating the through hole to the first surface by anisotropic etching;
[0017]
  First, primary etching is performed, and etching is performed up to the tip of the first guide portion. Thereby, the through-hole in the middle of formation reaches the front-end | tip of a guide part reliably and rapidly. Thereafter, switching to anisotropic etching is performed, and the through hole is made to penetrate to the substrate surface. By performing the secondary etching by anisotropic etching, the thickness of the opening edge of the substrate surface of the through hole can be formed thicker than in the case of isotropic etching.
[0018]
  A method for manufacturing a semiconductor device according to a sixth aspect of the present invention is the method for manufacturing a semiconductor device according to any one of the first to fifth aspects, wherein in the guide forming step, a second guide portion that is a groove-shaped or hole-shaped space is provided., On the first surface of the semiconductor substrateFurther form. In the through hole forming step, the semiconductor substrate is penetrated by etching the semiconductor substrate from the second surface side of the semiconductor substrate opposite to the first surface toward the first guide portion and the second guide portion. A through hole is formed.
[0019]
  When it is desired to form a large through hole with high accuracy, a plurality of guide portions are formed, and a through hole corresponding to each guide portion is formed. Thereby, a large through-hole can be formed at a target position with a target size.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
  <First embodiment>
  FIG. 1 shows a basic structure of a semiconductor device according to the first embodiment of the present invention. This semiconductor device has a semiconductor substrate 1 made of Si, GaAs, InP or the like in which a through hole 14 is formed, and a surface film 3 formed on at least a part of the substrate surface 1a.
[0021]
  Various functional portions may be formed on the surface 1a of the semiconductor substrate 1 depending on the type of device (see FIG. 3H described later). Here, the substrate surface 1a refers to a surface on which functional parts such as electrodes and various elements are formed. An opening 101 and an opening 102 are formed in the front surface 1 a and the back surface 1 b of the semiconductor substrate 1 by through holes 14, respectively. The planar shape of the openings 101 and 102 may be a rectangular shape or a strip shape, depending on the function portion formed on the surface 1a of the semiconductor substrate 1 or the function of the through hole 14.
[0022]
  The through hole 14 penetrates the semiconductor substrate 1 while narrowing the width from the substrate back surface 1b toward the surface 1a. The width W2 of the opening 102 on the substrate back surface 1b by the through hole 14 is wider than the width W1 of the opening 101 on the substrate surface 1a (W2> W1). As will be described later, the through hole 14 is formed by etching from the substrate back surface 1b, and the vicinity of the opening 101 on the substrate surface 1a is formed by etching along the guide. The guide will be described later.
[0023]
  Next, a method for manufacturing the semiconductor device shown in FIG. 1 will be described with reference to FIGS. Here, a manufacturing method using a silicon substrate will be described as an example.
  First, a mask 2 such as SiN or SiO 2 is formed on the surface of the silicon substrate 1, and Si etching is performed from the substrate surface side using a technique such as high-density plasma etching via the mask 2 to form a groove shape having a width of about 1 μm or A rectangular guide 11 is formed on the silicon substrate 1 (FIG. 1A). If the width of the guide 11 does not exceed 1 μm, the opening of the guide 11 can be easily covered with the surface film 3 described later, which is preferable. As an etching condition, for example, SF6 is used as an etching gas, and anisotropic dry etching is performed. The guide 11 is formed to a depth that does not affect the surface device, for example, a depth of about 50 μm.
[0024]
  Next, lattice defects 12 are introduced into the silicon substrate surface exposed in the guide 11 ((B) in the figure). This is performed, for example, by nitriding the exposed silicon substrate surface with N 2 gas or NH 3 gas at a high temperature, eg, 1000 ° C. for about 10 minutes. This is because, as will be described later, when etching is performed from the back surface 1b of the substrate, the progress of the etching is guided around the guide 11 along the lattice defect 12.
[0025]
  Thereafter, the mask 2 is removed as necessary, and a flat surface film 3 is formed on the silicon substrate 1 by a CVD method or a thermal oxidation method, and the guide 11 is filled (FIG. 3C). As the material of the surface film 3, a material that can be etched at an etching rate faster than that of the semiconductor substrate 1 is selected by selecting an etchant. The material of the surface film 3 is preferably a material on which various elements can be formed by a normal semiconductor process. For example, a silicon substrate can be selectively etched with hydrofluoric acid, and the surface film 3 is formed using a polysilicon CVD film or a silicon thermal oxide film on which an integrated circuit can be formed. It is done. Of these, polysilicon is preferable for removing the surface film 3, which will be described later, because it can be selectively etched faster than silicon. A functional part 4 such as an integrated circuit is formed on the surface film 3, and a mask 5 such as SiN or SiO2 is formed on the back surface 1b of the substrate ((D) in the figure). For example, if the functional unit 4 is a semiconductor device used for a micropump, it is a valve, an arm, a fixing ring, or the like that constitutes a valve.
[0026]
  Further, through the mask 5, primary etching is performed from the substrate back surface 1 b by alkaline wet etching or acidic wet etching to form a through hole 14 up to the tip of the guide 11 ((E) in the figure). The etching conditions are adjusted so that the through hole 14 reaches the tip of the guide 11. For example, in the case of a 6-inch silicon substrate, for example, a 22% solution of TMAH (tetramethylammonium hydroxide) is used as an etchant, and etching is performed at 80 ° C. for 15 hours.
[0027]
  Secondary etching is performed subsequent to the primary etching, and the through holes 14 are made to reach the substrate surface 1a ((F) in the figure). In this process, since the etching proceeds along lattice defects formed around the guide 11, the through hole 14 is formed along the guide 11 and finally reaches the opening of the guide 11. In the second etching, anisotropic wet etching is preferably performed so that the opening end of the through hole 14 on the substrate surface 1a has a thickness. For example, when the (111) plane of silicon is desired, anisotropic etching is performed using TMAH (tetramethylammonium hydroxide) or the like. The etching conditions are adjusted so that the through hole 14 reaches the substrate surface 1a.
[0028]
  Thereafter, a part of the surface film 3 remaining in the through hole 14 is selectively etched and removed from the substrate back surface 1b side (FIG. 3G). For example, if the surface film 3 is a SiO film or a thermal oxide film formed by CVD, a part of the surface film 3 remaining in the through hole 14 can be removed with hydrofluoric acid or the like. At this time, a little etchant goes around to the substrate surface 1a side, and a part of the surface film 3 near the opening of the through hole 14 is also removed.
[0029]
  After removing a part of the surface film 3 remaining in the through hole 14, the third etching is further performed from the back surface, thereby expanding the width of the through hole 14 to a desired width W1, and the functional unit 4 is mounted. A semiconductor device is obtained (FIG. (H)). For the third etching, anisotropic wet etching is preferable for the same reason as the second etching. The etching conditions are adjusted so that a desired width W1 is obtained.
[0030]
  The semiconductor device thus obtained has a small opening width W1 of the substrate surface 1a of the through hole 14 and is formed at a desired position. Specifically, in the case of a 6-inch silicon substrate, a band-shaped or rectangular through-hole 14 having an opening width of about 20 μm can be formed on the surface of the silicon substrate. Therefore, the margin for the size shift or the position shift of the opening 101 can be reduced, and the downsizing and high density of the semiconductor chip using this device can be promoted. In addition, the size and position of the opening 101 of the substrate surface 1a can be prevented from shifting for each wafer or etching process, the yield can be improved, and the cost of the semiconductor chip using this device can be reduced.
[0031]
  <Other embodiment examples>
  (A) 4 and 5 show another method for manufacturing the semiconductor device shown in FIG. As in FIGS. 2 and 3, a semiconductor device using a silicon substrate will be described as an example.
  2A and 2B, the guide 11 is formed on the silicon substrate 1, and the silicon exposed to the guide 11 is directly nitrided to introduce lattice defects 12 around the guide 11 (FIG. A) (B)).
[0032]
  Thereafter, the mask 2 is removed as necessary, and a flat surface film 3 is formed on the silicon substrate 1 by CVD or the like, and the opening of the guide 11 is closed (FIG. 3C). Since the surface film 3 formed by plasma CVD or the like has a weaker property of covering the step than the film formed by the low pressure CVD method or the thermal oxide film, the surface film hardly enters the guide 11. The material of the surface film 3 is as described above. When using plasma CVD, for example, SiH_Four+ N₂A film is formed in an O atmosphere. Thereafter, in the same manner as described above, a functional unit 4 such as an integrated circuit is formed on the surface film 3, and a mask 5 such as SiN or SiO2 is formed on the back surface 1b of the substrate (FIG. 4D).
Further, through the mask 5, the first etching is performed from the back surface 1 b of the substrate by anisotropic or isotropic etching, and then the second etching is preferably performed by anisotropic etching in the same manner as described above, to the tip of the guide 11. The through hole 14 is formed (FIGS. (E) and (F)). Etching conditions are the same as described above.
[0033]
  After that, a part of the surface film 3 covering the through hole 14 is selectively etched away from the substrate back surface 1b side (FIG. 5G). For example, if the surface film 3 is SiO 2, a part of the surface film 3 blocking the through hole 14 and the surface film near the opening of the through hole 14 can be removed with hydrofluoric acid or the like. If the surface film 3 is polysilicon, the surface film 3 can be selectively and rapidly etched by isotropic or anisotropic etching of Si.
[0034]
  After removing a part of the surface film 3 covering the through hole 14, the third etching is further performed from the back surface by anisotropic wet etching as described above, and the width of the through hole 14 is increased to a desired width W1 (same as above). FIG. (H)). The etching conditions are adjusted so that a desired width W1 is obtained.
  According to this process, since there is almost no surface film 3 remaining in the through hole 14, there is an advantage that the surface film 3 can be removed quickly.
[0035]
  (B) When it is desired to accurately form the through-hole 14 having a relatively large opening, a plurality of guides 11a, 11b, and 11c are formed, and after the plurality of openings are formed on the substrate surface, the openings are communicated with each other. Two through holes can be obtained. 6 and 7 are explanatory views showing a method for manufacturing the through hole in this case.
  First, a mask 2 such as SiN or SiO 2 is formed on the surface of the silicon substrate 1, and high-density plasma etching is performed from the substrate surface side through the mask 2, and groove-shaped guides 11 a, 11 b, 11 c having a width of about 1 μm are formed into silicon. A substrate 1 is formed (FIG. 6A). Next, lattice defects are introduced into the silicon substrate surface exposed in each guide ((B) in the figure). Thereafter, the mask 2 is removed as necessary, and a flat surface film 3 is formed on the silicon substrate 1 by CVD, thermal oxidation, or the like, and the guide 11 is covered or buried (FIG. 3C). A functional part 4 such as an integrated circuit is formed on the surface film 3, and a mask 5 such as SiN or SiO2 is formed on the back surface 1b of the substrate (FIG. 4D).
[0036]
  Further, the first etching is performed from the substrate back surface 1b through the mask 5, and the through holes 14 are formed up to the tips of the guides 11a, 11b, and 11c (FIG. 5E). Subsequent to the primary etching, the secondary etching is preferably performed by anisotropic etching, and the through holes 14 reach the substrate surface 1a (FIG. 5F). In this process, since etching proceeds along the guide 11, the tip of the through hole 14 branches along the guides 11a, 11b, and 11c.
[0037]
  Thereafter, the surface film 3 covering a part of the opening of the through hole 14 is selectively etched and removed from the substrate back surface 1b side (FIG. 7G). Further, the third etching is preferably performed from the back surface by preferably anisotropic etching, the ends of the branched through holes 14 are connected, and the width is expanded to a desired width W1 ((H) in the figure).
  In this way, a large through hole, for example, a through hole having an opening width of 100 μm or more on the front surface, can be formed with an accurate size from the back surface to a target position.
[0038]
  (C) FIG. 8 shows a semiconductor device in which a plurality of through holes 14a and 14b are formed. A plurality of openings 101a and 101b are formed in the substrate surface 1a, and a plurality of openings 102a and 102b are formed in the substrate back surface 1b. A semiconductor device having a plurality of through holes can be manufactured by providing a plurality of guides on the semiconductor substrate 1 and forming independent through holes along the respective guides.
[0039]
【Example】
  [Micro pump]
  FIG. 9 shows an example in which the basic structure according to the first embodiment is applied to a micropump.
  FIGS. 9A to 9H show the manufacturing process of the main part of the micropump, and FIG. 9H shows the configuration of the main part of the micropump. As shown in FIG. 2H, the micropump includes a silicon substrate 21 on which valves 22a and 22b are formed, and two heat-resistant glass plates 31a and 31b bonded to both surfaces of the silicon substrate 21.
[0040]
  A partition plate 32, a liquid inlet 33, and a liquid outlet 34 are formed in the heat-resistant glass plate 31a. The partition plate 32 forms a pressure chamber 35 between the surface of the silicon substrate 21. A piezoelectric actuator (not shown) for vibrating the partition plate 32 is attached on the partition plate 32 to change the pressure in the pressure chamber 35.
  The silicon substrate 21 has through holes 23a, 23b, 23c, and 23d (through holes 23). Of these, valves 22a and 22b (valve 22) are attached to the through holes 23b and 23d, respectively. The through holes 23a and 23d are opened so as to match the positions of the inlet 33 and the outlet 34 formed in the heat-resistant glass plate 31a, respectively, and the liquid sucked from the inlet 14 passes through the through holes 23a, 23b, 23c and 23d. It is discharged from the outlet 15 through the sequential passages. The other two through holes 23 b and 23 c have openings in the pressure chamber 35 between the partition plate 32 and the surface of the silicon substrate 21. A liquid path 24 is formed between the rear surface of the silicon substrate 21 and the heat-resistant glass plate 31, so that the through hole 23a communicates with the through hole 23b and the through hole 23c communicates with the through hole 23d. .
[0041]
  Next, with reference to FIGS. 9A to 9H, a method for manufacturing the micropump shown in FIG. 5H will be described.
  FIGS. 9A and 9B show a process of forming the partition plate 32, the inlet 33, and the outlet 34 on the heat-resistant glass plate 31a. First, an etching mask, for example, Cr—Cu is vacuum-deposited on both surfaces of the heat-resistant glass plate 31a, and a resist 36 is formed by double-sided photoetching (see FIG. 5A). The etching mask and resist 36 correspond to the partition plate 32, the inlet 33, the outlet 34, and the pressure chamber 35. Next, the pressure chamber 35 on the back surface is formed using, for example, 50% HF liquid. Further, the partition plate 32 is formed by covering the pressure chamber 35 with wax or the like and etching the surface. The partition plate 32 is further covered with wax and further etched to form through holes corresponding to the inlet 33 and the outlet 34. Thereafter, the resist and the etching mask are removed (see FIG. 5B).
[0042]
  FIGS. 9C to 9G show a process for forming the valve 22 and the through hole 23 in the silicon substrate 21. First, the guides 110a, b, c, d and the lattice defects around the guide are formed on the (100) silicon substrate 21, for example, by the above-described method (see FIG. 4C). Further, an etching mask corresponding to the liquid path 24 is formed on the back surface of the silicon substrate 21 with, for example, SiO 2, and the liquid path 24 is formed by anisotropic etching (see (c) in the figure).
[0043]
  Next, a mask 25 having openings facing the guides 110 a to 110 d is formed on the front surface and the back surface of the silicon substrate 21. The mask 25 is made of, for example, Si3N4 or SiO2. Valves 22a and 22b are further formed on the mask on the surface of the silicon substrate 21 by CVD and plasma etching using a photoresist as a mask. (See (d) in the figure). Further, two-stage etching is performed from the back surface of the silicon substrate 21 protected by the mask 25, and the opening width is adjusted by etching, thereby forming the through holes 23b and 23d opened below the valves 22a and 22b (see FIG. (See FIGS. 4D and 4E). These two through holes are formed so that the width decreases from the back surface to the front surface, and the opening width on the front surface of the substrate can be adjusted to 20 μm or less, for example, if it is a 6-inch silicon substrate. it can.
[0044]
  Prior to forming the other two through holes 23a and 23c, the valves 22a and 22b formed on the surface of the silicon substrate 21 are protected by an etching mask 26 such as Si3N4 or SiO2 (see FIG. 8F). ). Thereafter, the silicon substrate 21 is etched from the surface in two stages, and the opening width is adjusted by etching, thereby forming the through holes 23a and 23c whose opening width becomes narrower from the substrate surface toward the back surface. Thereafter, the etching mask 26 covering the valves 22a and 22b is removed, and the silicon substrate 21 having the valves 22 and the through holes 23 is obtained (see (g) in the figure).
[0045]
  The heat-resistant glass plates 31a and 31 thus obtained and the silicon substrate 21 are joined by anodic bonding to obtain the micropump shown in FIG. The joining condition is, for example, a temperature of about 400 ° C., and a negative voltage of about 500 V is applied to the heat resistant glass plate side.
  In such a micro pump, since the lattice defects introduced around the guide 110 induce etching at the stage of forming the through hole 23, the opening position of the through hole 23 on the substrate surface is accurately controlled. Thereafter, by extending the width of the small through hole to a desired width by adjusting the etching conditions, the through hole 23 having the target width can be formed at the target position. Therefore, various elements and functional parts such as the valve 22, the pressure chamber 35, the liquid path 24, the inlet 33, and the outlet 34 can be formed on the silicon surface with high density.
[0046]
  Here, the micropump is taken as an example, but the present invention can be applied to various micromachines such as a microvalve and a flow sensor.
[0047]
【The invention's effect】
  According to the present invention, the direction of etching is guided by the guide formed in the semiconductor substrate, so that a through hole having an opening of a desired size at a target position is formed on one surface of the semiconductor substrate from the other surface. Can be formed.
  Further, since the opening position and size of the through hole can be controlled, a high-density semiconductor device can be stably produced with a high yield.
[Brief description of the drawings]
FIG. 1 is a cross-sectional configuration diagram of a semiconductor device according to a first embodiment of the present invention.
FIG. 2 is a view (1) showing a manufacturing process of the semiconductor device.
FIG. 3 is a view (2) showing a manufacturing process of the semiconductor device;
FIG. 4 is a view (1) showing another manufacturing process of the semiconductor device;
FIG. 5 is a view (2) showing another manufacturing process of the semiconductor device;
FIG. 6 is a view (1) showing still another manufacturing process of the semiconductor device;
FIG. 7 is a view (2) showing still another manufacturing process of the semiconductor device;
FIG. 8 is a cross-sectional configuration diagram of a semiconductor device according to another embodiment of the present invention.
FIG. 9 is a schematic cross-sectional configuration diagram when the semiconductor device is applied to a micropump.
  (A), (b) Explanatory drawing which shows the manufacturing process of a heat-resistant glass plate.
  (C) Guide formation and lattice defect introduction process.
  (D) Formation of a valve and a first etching process from the back surface.
  (E) State at the end of the second etching process from the back surface.
  (F) First etching step from the surface.
  (G) A state after completion of the formation of the through hole.
  (H) Sectional drawing which shows the structure of the principal part of a micropump.
FIG. 10 is a schematic cross-sectional configuration diagram of a conventional micropump.
  The structure and operation | movement explanatory drawing of the conventional micropump.
  (A) A micro pump in a discharge mode.
  (B) A micro pump in the discharge mode.
  (C) The top view of the valve | bulb of a micro pump, an inlet_port | entrance, and an exit.
[Explanation of symbols]
    1, 2: Semiconductor substrate
    2, 5: Mask
    3: Surface film
    4: Function section
  11, 110: Guide
  12: Lattice defects
  14: Through hole
101: Opening on the substrate surface side
102: Opening on the back side of the substrate
  22a, 22b: Valve
  23a, 23b, 23c, 23d: through hole
  25, 26: Mask

Claims (6)

A guide forming step of forming a first guide portion which is a groove-like or hole-like space on the first surface of the semiconductor substrate;
A defect introduction step for introducing a lattice defect into a semiconductor substrate around the first guide portion;
A through hole forming step of etching the semiconductor substrate from the second surface side of the semiconductor substrate opposite to the first surface toward the first guide portion to form a through hole penetrating the semiconductor substrate;
A method for manufacturing a semiconductor device, comprising:   The method for manufacturing a semiconductor device according to claim 1, further comprising a surface film forming step of forming a surface film covering at least the first guide portion on the first surface. The semiconductor substrate is a silicon substrate;
In the surface film formation step, the surface film is formed of a silicon oxide film or polysilicon.
A method for manufacturing a semiconductor device according to claim 1.   The method for manufacturing a semiconductor device according to claim 1, wherein, in the surface film formation step, the surface film is formed by CVD (Chemical Vapor Deposition). The through hole forming step includes
A primary etching step of forming a through hole to the tip of the first guide part by anisotropic etching or isotropic etching;
A second etching step of penetrating the through hole to the first surface by anisotropic etching;
The manufacturing method of the semiconductor device in any one of Claims 1-4 containing these. In the guide forming step, a second guide portion that is a groove-like or hole-like space is further formed on the first surface of the semiconductor substrate ,
The through hole forming step penetrates the semiconductor substrate by etching the semiconductor substrate from the second surface side of the semiconductor substrate opposite to the first surface toward the first guide portion and the second guide portion. Forming a through-hole,
The manufacturing method of the semiconductor device in any one of Claims 1-5.

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