JP2020136567A - Formation method of penetration hole and manufacturing method of electronic device - Google Patents

Abstract

To easily and effectively form a high accuracy penetration hole for a substrate by an etching.SOLUTION: A formation method of a penetration hole, includes: a step P2 of forming a catalyst film 7 to an etching object region 5 of one surface 1a of a substrate 1 in the substrate 1 in which a penetration hole 3 is formed; and a step P4 of etching a region 8 in which the substrate 1 is contacted to the catalyst film 7 so that the substrate 1 in a state where the catalyst film 7 is formed is contacted to an etching liquid. An outer shape 11 in a plan view of the etching object region 5 is corresponded to an outer shape 17 in the plan view of the penetration hole 3, and a whole shape 9 in the plan view of the etching object region 5 has a shape different from a whole shape 15 in the plan view of the penetration hole 3.SELECTED DRAWING: Figure 6

Description

The present invention relates to a method of forming through holes in a semiconductor substrate by utilizing metal catalyst etching and a method of manufacturing an electronic device.

Patent Document 1 describes a method of metal-assisted chemical etching. Further, Patent Document 2 describes a basic problem in metal-assisted chemical etching (MACE).

Japanese Unexamined Patent Publication No. 2016-58647 Japanese Unexamined Patent Publication No. 2017-201660

However, in Patent Document 2, it becomes difficult to replace the etching solution even at the interface between the catalyst metal film and silicon by permeating the etching solution, and only the edge of the catalyst metal can be etched. Therefore, a fine hole pattern is formed in the metal pattern. Attempts to solve this problem are described. However, since very fine photolithography processing is required, an i-line stepper and an electron beam drawing device are required, which causes a problem that the investment becomes very large and it is not practical.

The method for forming a through hole according to the present invention for solving the above problems includes a step of forming a catalyst film in an etching target region on one surface of the substrate and the catalyst film being formed on the substrate for forming the through hole. A step of contacting the substrate in a state with an etching solution to etch a region of the substrate in contact with the catalyst film is provided, and the outer shape of the etching target region in a plan view is the outer shape of the through hole in a plan view. Corresponding to the shape, the overall shape of the etching target region in a plan view is different from the overall shape of the through hole in a plan view.

FIG. 5 is a plan view showing an example of an etching target region and an overall shape of the through hole by the method for forming a through hole according to the first embodiment of the present invention. FIG. 5 is a plan view showing another example of the etching target region and the overall shape of the through hole according to the method for forming the through hole according to the first embodiment. FIG. 5 is a plan view showing another example of the etching target region and the overall shape of the through hole according to the method for forming the through hole according to the first embodiment. FIG. 5 is a plan view showing another example of the etching target region and the overall shape of the through hole according to the method for forming the through hole according to the first embodiment. The plan view which shows an example of the etching target area and the whole shape of a through hole by the method of forming a through hole which concerns on a conventional example. The explanatory view which shows the process of formation in the method of forming a through hole which concerns on Embodiment 1 of this invention. A cross-sectional image of a substrate by a microscope showing the results of a test conducted to test the effect of the method for forming a through hole according to the first embodiment. Explanatory drawing which shows the process of formation in the method of forming a through hole which concerns on Embodiment 2 of this invention. The perspective view which shows typically the electronic device manufactured by the manufacturing method of the electronic device which concerns on Embodiment 3 of this invention.

First, the present invention will be described schematically.
The method for forming a through hole according to the first aspect of the present invention for solving the above problems is a step of forming a catalyst film in an etching target region on one surface of the substrate in a substrate for forming the through hole, and the catalyst film. The substrate is brought into contact with the etching solution to etch the region of the substrate in contact with the catalyst film, and the outer shape of the etching target region in a plan view is the through hole. Corresponding to the outer shape in the plan view, the overall shape of the etching target region in the plan view is different from the overall shape of the through hole in the plan view.

Here, the "contact region" in the "region in contact with the catalyst film of the substrate" is not limited to the portion in which the two are strictly in contact, and the non-contact portion around the region is also etched by the catalyst. , It is used in the present specification in the sense that it includes a region where etching is performed in a non-contact manner.
Further, "corresponding to the outer shape of the through hole in the plan view" in "the outer shape of the etching target region in the plan view corresponds to the outer shape of the through hole in the plan view" means the plane of the etching target region. It means that the outer shape in view corresponds not to the overall shape of the through hole but to the shape formed by the outer peripheral portion of the through hole, in other words, the "outer circumference shape" in shape and size.

According to this aspect, the outer shape of the catalyst film formed in the etching target region corresponds to the outer shape or the outer peripheral shape of the through hole in a plan view, and the entire catalyst film formed in the etching target region is formed. The shape is different from the overall shape of the through hole in a plan view. In this way, by making the overall shape of the catalyst membrane different from the overall shape of the through hole, it is possible to make the edging shape corresponding to the shape of the outer peripheral portion of the through hole. By making the entire shape of the catalyst membrane a border shape, the formation of the catalyst membrane itself becomes easy.
Further, the catalyst film having the edging shape has a range in which the etching solution should be distributed, that is, an area, rather than a structure in which the catalyst film is formed so as to cover the entire portion corresponding to the through hole instead of the edging shape. The amount is small, and the liquid exchange is facilitated by permeating the etching liquid into the etching target area.
Further, the portion surrounded by the edging-shaped catalyst film is not etched and remains, but when the etching of the edging-shaped portion around the portion is completed, the portion is separated from the substrate. Become. In this separated state, it can be easily removed from the substrate, and thus a through hole can be easily formed.

A second aspect according to the present invention is characterized in that, in the first aspect, the overall shape of the catalyst film formed in the etching target region in a plan view is a ring shape.
Here, the "ring shape" is not limited to a circular shape or an elliptical shape, but includes a edging shape such as a polygon such as a quadrangle or a cross frame shape, and means a edging shape as a surrounding frame that surrounds the inside from the periphery. ..

According to this aspect, since the overall shape of the catalyst membrane in a plan view is a ring shape, the above-mentioned action effect of the first aspect can be obtained by simplifying the structure.

The method for forming a through hole according to a third aspect of the present invention is a state in which a ring-shaped catalyst film corresponding to the outer shape of the through hole in a plan view is formed on the substrate on which the through hole is formed, and the catalyst film is provided. The substrate is brought into contact with the etching solution, the etching reaction is allowed to proceed in the etching target region where the substrate is in contact with the catalyst film, and the ring-shaped catalyst film is formed from the surface of the substrate on which the catalyst film is formed. It is characterized in that the through hole having a volume larger than the etching volume is formed by moving the film toward a surface opposite to the surface on which the film is formed.
Here, the "etching volume" means the volume of the portion removed by etching with an etching solution. And, "the through hole having a volume larger than the etching volume" literally means that the volume of the through hole is larger than the etching volume.

According to this aspect, a ring-shaped catalyst film corresponding to the outer shape or outer peripheral shape of the through hole in a plan view is formed on the surface of a substrate on which a through hole is formed by etching, and the ring-shaped catalyst film is formed on the substrate. Since the through hole having a volume larger than the etching volume is formed by moving from the front surface to the back surface of the above, the structure can be simplified and the same effect as in the first aspect can be obtained.

A fourth aspect according to the present invention is characterized in that, in the second or third aspect, the line width of the catalyst membrane forming the ring shape is 1 μm or more and 10 μm or less.

According to this aspect, since the line width of the catalyst membrane forming the ring shape is 1 μm or more and 10 μm or less, the ring shape of the catalyst membrane can allow the etching reaction to proceed while maintaining the shape. .. In addition, liquid exchange by permeating the etching liquid into the etching target region becomes easy.

A fifth aspect according to the present invention is characterized in that, in any one of the first to fourth aspects, the film thickness of the catalyst membrane is 5 nm or more and 100 nm or less.

According to this aspect, the film thickness of the catalyst membrane is 5 nm or more and 100 nm or less. That is, the film thickness is neither too thin nor too thick. If the film thickness of the catalyst film is too thin, it will be in a state close to the state where it exists in an island-like structure, and only micropores are formed on the substrate, and there is a possibility that etching of the etching target region cannot be performed. However, this aspect can reduce the risk. Further, if the thickness is too thick, the film may be curled or deformed due to the stress of the film, and the desired shape may not be formed. Therefore, the etching reaction may be slowed down, but this possibility is reduced by this embodiment. can do.

In a sixth aspect according to the present invention, in any one of the first to fifth aspects, the etching target region is opened on the one surface of the substrate prior to the formation of the catalyst film. It has a step of forming a mask, and the resist used for forming the mask is a negative type.

According to this aspect, since the resist used for forming the mask is a negative type, when the mask having the aperture is formed on the substrate surface by photolithography, the exposure amount of the exposure machine is adjusted to obtain light. It is possible to easily form an opening corresponding to the target line width by utilizing the wraparound of.

In a seventh aspect according to the present invention, in any one of the first to sixth aspects, the etching target region is opened on the one surface of the substrate prior to the formation of the catalyst film. The mask is formed in two or more layers, and the opening is formed into an overhang shape in a side view from the etching target region side toward the opening side of the mask. To do.

According to this aspect, since the opening has an overhang shape in a side view from the etching target region side toward the opening side of the mask, when the catalyst film is formed, the space between the substrate surface and the mask is formed. The continuity of the catalyst membrane in the above can be cut. As a result, the catalyst film can be accurately provided in the etching target region.

An eighth aspect of the present invention is to provide a first wiring provided on the one surface of the substrate having a through hole and a second wiring provided on a surface opposite to the one surface of the substrate. It is a method for manufacturing an electronic device to have, characterized in that it is formed by the method for forming a through hole in any one of the first to seventh aspects.

According to this aspect, it is possible to easily manufacture an electronic device having a through hole and having wiring on one side and the other side.

Subsequently, taking the three embodiments of the first embodiment, the second embodiment, and the third embodiment as examples, the method of forming the through hole and the method of manufacturing the electronic device according to the embodiment of the present invention will be described in detail with reference to the reference drawings. explain.
In the following description, first, the basic contents of the method for forming a through hole according to the embodiment of the present invention will be described with reference to FIG. Next, the relationship between the etching target region and the overall shape of the through hole according to the embodiment of the present invention shown in FIGS. 1 to 4 is compared with the relationship between the etching target region and the overall shape of the through hole according to the conventional row shown in FIG. I will explain in detail.

Next, the specific contents of the method for forming a through hole according to the first embodiment of the present invention will be specifically described according to the process of forming the through hole based on FIG. Subsequently, the test contents and test results of the through hole formed according to the first embodiment of the present invention will be described with reference to FIG. 7, and the action and effect of the through hole forming method according to the first embodiment of the present invention will be referred to.
Next, the specific contents of the method for forming a through hole according to the second embodiment of the present invention will be specifically described with reference to FIG. 8, focusing on the differences from the first embodiment according to the process of forming the through hole. The action and effect are mentioned. Further, a specific content of the method for manufacturing an electronic device according to the third embodiment of the present invention will be described with reference to FIG. Finally, another embodiment of the method for forming a through hole and the method for manufacturing an electronic device of the present invention, which are partially different from these three embodiments, will be briefly described.

[Embodiment 1]
(1) Basic contents of the method of forming a through hole (see FIGS. 1 and 6)
The method for forming the through hole of the present embodiment is a step (hereinafter referred to as a forming step) P2 of forming the catalyst film 7 in the etching target region 5 on the surface 1a of the substrate 1 on which the through hole 3 is formed by etching, and the catalyst film. It is configured by having a step (hereinafter referred to as an etching step) P4 in which the substrate 1 in the state where the 7 is formed is brought into contact with the etching solution and the region 8 in contact with the catalyst film 7 of the substrate 1 is etched.
Then, in the present embodiment, the outer shape 11 of the etching target region 5 is formed to have the same shape and the same size corresponding to the outer shape (outer peripheral shape) 17 in the plan view of the through hole 3. Further, the overall shape 9 of the etching target region 5 is formed in a shape different from the overall shape 15 in the plan view of the through hole 3, that is, a shape in which one or both of the shape and the size are different.

Specifically, in the present embodiment, the overall shape 9 of the catalyst film 7 formed in the etching target region 5 in a plan view is formed into a ring shape. As a result, the overall shape 9 of the etching target region 5 is composed of the outer peripheral shape 11 of the etching target region 5 and the inner peripheral shape 13 of the etching target region 5.
On the other hand, the overall shape 15 of the through hole 3 is composed of only the outer shape 17 of the through hole 3 as described above.

(2) Relationship between the overall shape of the etching target area and the overall shape of the through hole (see FIGS. 1 to 5)
Next, the relationship between the overall shape 9 of the etching target region 5 of the present embodiment shown in FIGS. 1 to 4 and the overall shape 15 of the through hole 3 is shown with the overall shape 109 of the etching target region 105 according to the conventional example shown in FIG. This will be specifically described in comparison with the relationship of the overall shape 115 of the through hole 103.
In the present embodiment, various ring-shaped shapes can be adopted as the overall shape 9 of the etching target region 5. For example, an annular frame as shown in FIG. 1, a rectangular frame as shown in FIG. 2, a cross frame as shown in FIG. 3, or a polygonal frame such as a pentagon as shown in FIG. It is possible to adopt a shape or the like as the overall shape 9 of the etching target region 5.

In the overall shape 9 of the etching target region 5, the outer peripheral shape 11 is a polygon such as a circle, a rectangle, a cross, or a pentagon, respectively, and the inner peripheral shape 13 is described later from the outer peripheral shape 11, respectively. The catalyst film 7 is formed in a polygonal shape such as a circle, a rectangle, a cross shape, or a pentagon, which is one size smaller than the cotton width W.
On the other hand, the overall shape 15 of the through hole 3 formed by the etching target region 5 has the same shape and size as the outer peripheral shape 11 of the etching target region 5, and has many shapes such as a circle, a rectangle, a cross shape, and a pentagon, respectively. It is composed of a rectangular outer shape 17.

On the other hand, in the conventional example, the overall shape 109 of the etching target region 105 is composed of only the circular outer shape 111 as shown in FIG. 5, for example, and the through hole formed by such an etching target region 105. The overall shape 115 of 103 has the same shape and size as the overall shape 109 of the etching target region 105, for example, a circular outer shape 117.
That is, the basic difference between the present embodiment and the conventional example is that in the conventional example, when the through hole 103 is formed, the entire shape 115 of the through hole 103 is set as the etching target region 105, whereas in the present embodiment, the etching target region 105 is used. In the embodiment, the etching target region 5 is a part of the outer peripheral side of the overall shape 115 of the through hole 3. However, the final shapes of the formed through holes 3 and 103 are outer shapes 17 and 117 having the same shape and size as shown in FIGS. 1 and 5.

(3) Specific contents of the method of forming a through hole (see FIG. 6)
Next, the specific contents of the method for forming a through hole according to the first embodiment of the present invention will be specifically described according to the process of forming the through hole 3 based on FIG.
The method for forming the through hole according to the present embodiment includes a forming step P2 for forming the ring-shaped catalyst film 7 and an etching step P4 for bringing the substrate 1 into contact with the etching solution as described above. Then, in the above description, the difference between the etching target region 5 and the through hole 3 has been described from the viewpoint of the overall shape, but it will be as follows from the viewpoint of each volume V.

That is, in the present embodiment, in the etching step P4, the ring-shaped catalyst film 7 is directed from the front surface 1a to the back surface 1b of the substrate 1 by advancing the etching reaction in the etching target region 5 in contact with the catalyst film 7 of the substrate 1. To form a through hole 3 having a volume V2 larger than the etching volume V1.
That is, the volume V2 of the through hole 3 includes, in addition to the annular etching volume V1, the volume V3 of the falling portion 6 inside the etching volume V1 that is dropped and removed, and the relationship of V2 = V1 + V3. It has become.

Further, in the method for forming a through hole according to the present embodiment, a mask forming step P1 for forming a mask 19 by opening an etching target region 5 on the surface 1a of the substrate 1 is provided prior to the forming step P2. A mask removing step P3 for removing the formed mask 19 as a subsequent step of the forming step P2 is provided.
Then, in the mask forming step P1, a resist film 21 formed as an example by a negative type in which the portion exposed to exposure by exposure becomes a wiring pattern 31 is formed. The contents of these four steps will be specifically described below.

(A) Mask forming step The mask forming step P1 is a step of forming a layer of mask 19 composed of a resist film 21 on the surface 1a of the substrate 1.
Specifically, a resist, which is a photosensitive material, is applied to the surface 1a of a substrate 1 made of a silicon wafer base material or the like, and a predetermined line width is formed on the outer peripheral portion thereof so as to border the outer shape 17 of the through hole 3 formed. A negative-type resist film 21 on which the W pattern holes 33 are formed is formed.

The line width W of the pattern hole 33 formed in the resist film 21 is preferably as narrow as possible, and its size largely depends on the resolution of the drilling device for drilling the through hole 3 in the substrate 1, particularly the exposure machine. Further, since the negative type resist film 21 is used in this embodiment, the effect of light wraparound can be expected by overexposing the exposure amount, whereby the line width W is narrower than the resolution of the exposure machine. The ring-shaped through hole 3 can be formed.
The line width W of the pattern hole 33 of the resist film 21 is set to 1 μm or more and 10 μm or less, preferably 1 μm or more and 4 μm or less. As a result, the line width W of the ring-shaped catalyst film 7 formed in the forming step P2 of the next step (using the same reference numeral as the line width W of the pattern hole 33 of the resist film 21) is also 1 μm or more and 10 μm or less. Desirably, it is 1 μm or more and 4 μm or less.

(B) Forming Step The forming step P2 is a step of forming the catalyst film 7 in the etching target region 5 of the surface 1a of the substrate 1.
Specifically, by forming a catalytically active ultrathin metal such as gold (Au) on the resist film 21 that functions as a mask 19, a catalyst film made of gold (Au) or the like is formed in the etching target region 5. 7 is formed. The catalyst film 7 may be formed by dry forming such as sputtering or thin film deposition, or by wet forming such as substitution plating or electroless plating.

The film thickness T of the catalyst film 7 is preferably 5 nm or more and 100 nm or less, preferably 10 nm or more and 50 nm, although it depends on the forming method and the film quality. Incidentally, when the film thickness T of the catalyst film 7 is thicker than 100 nm, the etching rate in the etching step P4 described later becomes very slow, and the practicality becomes low. On the other hand, when the film thickness T of the catalyst film 7 becomes a thin film of less than 5 nm, the catalyst film 7 exists as an island-like structure and only allows micropores to be formed in the substrate 1 to form through holes 3 having a desired shape. I can't do it. Therefore, in the present embodiment, the film thickness T of the catalyst membrane 7 is set to about 18 nm as an example, whereby the catalyst membrane 7 develops from an island-like structure to a network-like structure, and a large number of voids are present. A good etching reaction can be expected.

(C) Mask Removal Step The mask removing step P3 is a step of removing the mask 19 from the surface 1a of the substrate 1 after the catalyst film 7 is formed.
Specifically, although the present step P3 is executed by peeling the resist film 21, it is desirable that the resist film 21 be peeled off in an environment as low as possible. Therefore, in this embodiment, N-methyl-2- The pyrrolidone solution was heated to 50 ° C. for use, then immersed in isopropanol, replaced, washed with pure water, and dried to peel off the resist film 21.

(D) Etching Step The etching step P4 is a step of bringing the substrate 1 in a state where the catalyst film 7 is formed and the mask 19 removed into contact with the etching solution to etch the region 8 of the substrate 1 in contact with the catalyst film 7.
Specifically, a method by metal-assisted chemical etching (MACE) using a noble metal as a catalyst can be adopted. As an example, the substrate 1 on which the catalyst film 7 formed by the gold (Au) film is formed is an aqueous solution of hydrogen peroxide. Etching is performed by immersing the HF aqueous solution in an etching solution in which an oxidizing agent such as hydrogen peroxide solution is mixed.

It is desirable that the etching is performed at a temperature in the range of room temperature (20 ° C.) to 50 ° C. in order to prevent volatilization of HF, hydrogen peroxide solution, and the like. Further, when etching with an etching depth D of 90 μm is performed, the etching time is about 2 hours, and further, by lengthening the etching time, etching with an etching depth D of more than 90 μm becomes possible.
Due to etching by MACE, the catalyst film 7 moves vertically as the etching progresses. As a result, a ring-shaped etching hole 35 penetrating from the front surface 1a to the back surface 1b can be formed on the substrate 1, and the etching hole can be further subjected to an impact such as megasonic or by applying a water stream during washing with water after etching. The falling portion 6 of the substrate 1 that remains inside the 35 falls off, and the through hole 3 having the predetermined shape is formed.

(4) Through-hole test content and test results (see Fig. 7)
In FIG. 7, the substrate 1 is placed flat under the condition that the room temperature is 23 ° C., and the catalyst film 7 having a line width W of 4 μm is used for 2 hours in order to drill a circular through hole 3 having a diameter A of 20 μm in a plan view. It shows a cross-sectional image of the substrate 1 by a microscope at the time of etching.
In this cross-sectional image, the etching depth D = 90.5 μm is reached, and it is presumed that etching with an etching depth D = 90 μm is easily possible in the vertical direction. The direction of etching is not limited to the form in which the substrate 1 is placed horizontally and the etching proceeds in the vertical direction, and it is also possible to adopt the form in which the substrate 1 is placed vertically and the etching proceeds in the horizontal direction. ..

Then, according to the method for forming a through hole according to the present embodiment configured in this way, etching is performed on the ring-shaped etching target region 5 having an area S2 smaller than the opening area S1 of the through hole 3 to be formed. As a result, it becomes easy to exchange the etching solution with respect to the interface between the catalyst metal such as gold (Au) and the substrate 1, and the etching rate can be increased.
Further, by adopting the negative type resist film 21 and the above-mentioned catalyst film 7 having a line width W and a film thickness T, fine through holes 3 are accurately formed in the substrate 1 and a wiring pattern having a desired shape is formed. It becomes possible to easily form 31. Further, according to the method for forming a through hole according to the present embodiment, the through hole 3 can be formed by using a low-priced exposure machine, so that the equipment cost can be kept low and the through hole 3 can be formed with high accuracy. It will be possible.

[Embodiment 2]
(1) Specific contents of the method of forming a through hole (see FIG. 8)
In the method for forming through holes according to the second embodiment, a mask 19 composed of two or more layers is used, and by changing the sizes of the openings 37 and 38 formed in each layer, the etching target region 5 side (mask 19). A mask 19 having a pattern hole 33 having an overhang shape in a side view from the opening end side of the pattern hole 33 to the opening side of the mask 19 (opening start side of the pattern hole 33 of the mask 19) is used.
Along with this, the mask forming step P1 is subdivided into a plurality of steps, and the content of the mask removing step P3 is also partially different from the content of the through hole forming method of the first embodiment. Since the contents of the other steps are basically the same as those of the first embodiment, the contents specific to the second embodiment, which are different from the first embodiment, will be mainly described here.

In resist patterning using the resist film 21, when the resist film 21 is peeled off after vapor deposition using gold (Au) or the like, the pattern holes 33 formed in the resist film 21 are overlaid with an inverted trapezoid or an inverted conical trapezoid. It is desirable to have a hang shape. However, as described above, it is difficult to form such a resist film 21 in the resist film 21 that forms the pattern hole 33 having a small line width W. Therefore, for example, another film that can be patterned by wet etching is prepared. Then, a mask 19 having a multilayer structure in which this film and the resist film 21 are combined is formed and used.
Specifically, the mask forming step P1 is divided into three steps of an auxiliary film forming step P11, a resist film forming step P12, and a pattern hole forming step P13 to form a mask 19 having a multilayer structure.

(A) Auxiliary film forming step The auxiliary film forming step P11 is a step of forming an auxiliary film 22 to be used as a mask 19 in combination with the resist film 21.
Specifically, as an example, the auxiliary film 22 made of SiO ₂ is formed on the surface 1a of the substrate 1 with a thickness of 0.5 μm as an example to form the auxiliary film 22 on the substrate 1. In forming the auxiliary film 22, as an example, a method such as thermal oxidation, chemical vapor deposition (CVD), or sputtering in which high-energy ion particles are irradiated and collided to form a thin film can be adopted.

(B) Resist film forming step The resist film forming step P12 is a step of forming the resist film 21 on the auxiliary film 22 formed on the surface of the substrate 1a by the auxiliary film forming step P11.
The resist film 21 is formed with a small opening 37 having a line width W1 that is a part of the pattern hole 33, and is formed in the same manner as the negative type resist film 21 used in the first embodiment.

(C) Pattern hole forming step In the pattern hole forming step P13, an opening 38 having a line width W2 larger than the line width W1 of the opening 37 of the resist film 21 is formed in the auxiliary film 22 formed in the auxiliary film forming step P11. This is a step of forming an overhang-shaped pattern hole 33 in which the opening 37 of the resist film 21 and the opening 38 of the auxiliary film 22 are combined.
Specifically, a buffered hydrofluoric acid solution is allowed to act on the auxiliary film 22 formed of the SiO ₂ film as an example to perform wet etching. By setting the etching time at this time to be longer than the appropriate etching time, the line width W2 of the opening 38 of the auxiliary film 22 becomes large, and an overhang-shaped pattern hole 33 is formed.

Incidentally, by forming the pattern hole 33 of the mask 19 into an overhang shape, it is possible to cut off the continuity of the catalyst film 7 formed by a metal film such as gold (Au) between the substrate 1 and the resist film 21. Therefore, it becomes possible to maintain the overall shape of the etching target region 5 in the catalyst film 7 with high accuracy.

(D) Mask Removal Step The mask removing step P3 is a step of removing the mask 19 from the surface 1a of the substrate 1 after the catalyst film 7 is formed, as in the first embodiment. However, since the mask 19 having a multilayer structure composed of the resist film 21 and the auxiliary film 22 is used in the present embodiment, there are two types of objects to be removed, the resist film 21 and the auxiliary film 22. Therefore, two types of removal corresponding to the resist film 21 and the auxiliary film 22 are carried out.
In this case, first, the resist film 21 formed on the surface of the auxiliary film 22 is removed. The removal of the resist film 21 can be carried out by the same procedure as described in the first embodiment.

On the other hand, the removal of the auxiliary film 22 is carried out in the etching step P4. That is, in the etching step P4, as described in the description of the first embodiment, a solution obtained by mixing an oxidizing agent such as a hydrogen peroxide solution with an HF aqueous solution is used, so that an auxiliary film formed on the surface 1a of the substrate 1 is used. 22 dissolves and disappears in response to the etching solution containing HF.
In this embodiment, the etching is performed for about 6 hours as an example, which is longer than the etching time described in the first embodiment.

(2) Actions and effects of the through-hole forming method The same actions and effects as those of the first embodiment are also exhibited by the through-hole forming method according to the present embodiment configured in this manner, and the etching solution Replacement becomes easy, the etching rate can be increased, and fine through holes 3 can be formed in the substrate 1 with high accuracy to freely form a wiring pattern 31 having a desired shape. ..
Further, according to the present embodiment, by forming the pattern hole 33 of the mask 19 into an overhang shape, the continuity of the catalyst film 7 between the substrate 1 and the resist film 21 is cut off, and the accuracy is further improved. The through hole 3 can be formed.

[Embodiment 3]
Next, as the third embodiment, the method of manufacturing the electronic device of the present embodiment will be described with reference to FIG. The method for manufacturing this electronic device is to provide the first wiring 23 (wiring pattern 31A) provided on one surface (for example, the front surface 1a) of the substrate 1 having the through hole 3 and the other surface (for example, the back surface 1b) of the substrate 1. A method for manufacturing an electronic device 27 having the second wiring 25 (wiring pattern 31B), wherein the through hole 3 is formed by the method for forming the through hole according to the first embodiment or the second embodiment. It is characterized by.

As the electronic device 27, a silicon wafer in which wiring patterns 31 such as IC chips, that is, fine wirings and elements of semiconductor integrated circuits are regularly arranged in a grid pattern on the front surface 1a and the back surface 1b are cut out from the silicon wafer. IC chips, LSIs made from IC chips, that is, electronic components such as large-scale integrated circuits, or printers, scanners, liquid crystal projectors, personal computers (PCs), etc. made by combining these electronic components. This applies to all types of electronic circuit components that require a through-hole structure, such as electronic substrates.
In such an electronic device 27, as schematically shown in FIG. 9, the first wiring 23 (wiring pattern 31A) and the second wiring 25 (wiring pattern 31B) are provided on the front surface 1a and the back surface 1b of the substrate 1. A through hole is provided for the purpose of forming a wiring pattern 31C which is a through electrode for connecting the first wiring 23 (wiring pattern 31A) and the second wiring 25 (wiring pattern 31B). 3 is formed.

Then, as a means for forming the through hole 3 in the substrate 1 of the electronic device 27 configured in this way, the method for forming the through hole according to the first embodiment or the second embodiment is used.
Therefore, also in the method for manufacturing the electronic device of the present embodiment, the action and effect of the method for forming the through hole according to the first or second embodiment can be exhibited so that the high-precision electronic device 27 can be efficiently manufactured. Become

[Other Embodiments]
The method for forming a through hole and the method for manufacturing an electronic device according to the present invention are based on having the above-described configuration, but the partial configuration does not deviate from the gist of the present invention. Of course, it is possible to make changes or omissions.

For example, the outer peripheral shape 11 and the inner peripheral shape 13 of the catalyst film 7 formed in the etching target region 5 are not limited to the shapes shown in FIGS. 1 to 4, and may be elliptical or oval, and the corner portions are chamfered. It may be an elliptical quadrangle or a rounded quadrangle. In addition, a special shape such as a star shape, a heart shape, or a gear shape, or a composite shape in which a plurality of these shapes are combined may be used.
Further, the through hole 3 formed in the substrate 1 is not only formed of a ring shape, but can also be a through hole 3 having a complicated shape in which a line shape, a block shape, or the like is combined with the ring shape.

1 ... Substrate, 1a ... Front surface, 1b ... Back surface, 3 ... Through hole, 5 ... Etching target area,
6 ... Dropped out part, 7 ... Catalyst membrane, 8 ... Region in contact (with catalyst membrane),
9 ... Overall shape (of the etching target area),
11 ... External shape (outer peripheral shape) (of the etching target area),
13 ... Inner circumference shape (of the etching target area), 15 ... Overall shape (of the through hole),
17 ... External shape (through hole), 19 ... Mask, 21 ... Resist film, 22 ... Auxiliary film,
23 ... 1st wiring, 25 ... 2nd wiring, 27 ... Electronic device,
31 ... Wiring pattern (wiring), 33 ... Pattern hole, 35 ... Etching hole, 37 ... Opening,
38 ... opening, P1 ... mask forming step, P2 ... forming step, P3 ... mask removing step,
P4 ... Etching step, P11 ... Auxiliary film forming step, P12 ... Resist film forming step,
P13 ... Pattern pore forming step, W ... Line width (of catalyst film), T ... Film thickness (of catalyst film),
V ... Volume, D ... Etching depth, A ... Diameter, S ... Area

Claims (8)

In a substrate for forming a through hole, a step of forming a catalyst film in an etching target region on one surface of the substrate, and
It has a step of bringing the substrate in a state where the catalyst film is formed into contact with an etching solution and etching a region of the substrate in contact with the catalyst film.
The outer shape of the etching target region in a plan view corresponds to the outer shape of the through hole in a plan view.
A method for forming a through hole, characterized in that the overall shape of the etching target region in a plan view is different from the overall shape of the through hole in a plan view. In the method for forming a through hole according to claim 1,
A method for forming a through hole, characterized in that the overall shape of the catalyst film formed in the etching target region in a plan view is a ring shape. In the substrate on which the through hole is formed, a ring-shaped catalyst film corresponding to the outer shape of the through hole in a plan view is formed.
The substrate having the catalyst film is brought into contact with the etching solution to bring it into contact with the etching solution.
The etching reaction is allowed to proceed in the etching target region where the substrate is in contact with the catalyst film, and the ring-shaped catalyst film is formed from the surface of the substrate on which the catalyst film is formed to the side opposite to the surface on which the catalyst film is formed. A method for forming a through hole, which comprises moving the through hole toward the surface of the surface to form the through hole having a volume larger than the etching volume. In the method for forming a through hole according to claim 2 or 3.
A method for forming a through hole, wherein the line width of the catalyst membrane having a ring shape is 1 μm or more and 10 μm or less. In the method for forming a through hole according to any one of claims 1 to 4.
A method for forming through holes, wherein the catalyst film has a film thickness of 5 nm or more and 100 nm or less. In the method for forming a through hole according to any one of claims 1 to 5,
Prior to the formation of the catalyst film, there is a step of opening the etching target region on the one surface of the substrate to form a mask.
A method for forming a through hole, characterized in that the resist used for forming the mask is a negative type. In the method for forming a through hole according to any one of claims 1 to 6,
Prior to the formation of the catalyst film, there is a step of opening the etching target region on the one surface of the substrate to form a mask.
The mask forms two or more layers and
A method for forming a through hole, wherein the opening has an overhang shape in a side view from the etching target region side toward the opening side of the mask. A first wiring provided on the one surface of the substrate having a through hole, and
A method for manufacturing an electronic device having a second wiring provided on a surface opposite to the one surface of the substrate.
A method for manufacturing an electronic device, characterized in that the through hole is formed by the forming method according to any one of claims 1 to 7.

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