JP2001307970A - Method of jointing substrates - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of jointing substrates for reducing the cost without limiting materials and for eliminating a defect in process caused by deformation at heat, residual stress and the like. SOLUTION: A nickel film 5 is formed on the rear face of a substrate 1, and each through hole is drilled in the substrate 1 and a substrate 6. The substrate 6 is put on the substrate 1, and plating is formed in the through hole to joint the substrate 1 and the substrate 6. Alternatively, the hole with a bottom is filled with plating in the substrate 1, and a through hole that passes through the hole with the bottom is drilled in the substrate 1. A through hole is drilled also in the substrate 6. Then, the substrate 6 is put on the substrate 1 and jointed to each other. In addition, the through holes in the substrates 1 and 6 may be drilled at a time when the substrate 6 is put on the substrate 1. The drilling step is carried out in an anisotropic wet etching method, a DEEP-RIE method, or a dicing method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of joining substrates for integrally joining a plurality of substrates.

[0002]

2. Description of the Related Art Conventionally, semiconductor pressure sensors utilizing the piezo effect have been used for various pressure measurements. FIG.
6A is a cross-sectional view showing the configuration of the semiconductor pressure sensor, 8 is a substantially flat silicon (Si) substrate, and 9 is a substantially flat glass (SiO ₂ ) on which the silicon substrate 8 is mounted.
It is a substrate. On the back side of the silicon substrate 8, a substantially truncated quadrangular pyramid is formed, whereby a diaphragm 8a is formed, and a piezo resistor 8b is formed on the front side of the diaphragm 8a.

At the center of the glass substrate 9, a pressure introducing hole 9a for guiding external pressure to the diaphragm 8a of the silicon substrate 8 is formed. Then, pressure is applied from the outside, and the diaphragm 8a is pressed through the pressure introducing hole 9a.
As the piezoresistor 8b is deformed by receiving pressure, the piezoresistor 8b on the surface of the piezoresistor is also deformed according to the applied pressure and changes its resistance value. It is supposed to be.

Here, the silicon substrate 8 and the glass substrate 9 are separately processed and joined, and anodic bonding is known as one of the joining methods of the silicon substrate 8 and the glass substrate 9. In this joining method, a glass substrate 9 called Pyrex (registered trademark) glass made of glass containing mobile ions such as Na ⁺ is used. Later, FIG.
As shown in (b), the silicon substrate 8 is placed on a hot plate 10 which is a heater, and the glass substrate 9 is placed on the silicon substrate 8 with the surface on which the piezoresistor is formed facing downward. .

Next, the silicon substrate 8 is connected via the hot plate 10 so that the silicon substrate 8 has a positive potential.
A voltage of 200 to 1000 V is applied between the glass substrate 9 and the hot plate 10 to raise the entire temperature of the silicon substrate 8 and the glass substrate 9 to around 450 ° C. By doing so, Na ⁺ contained in the glass substrate 9 becomes easy to move and is pulled to a negative potential and reaches the surface layer of the glass substrate 9, so that a large amount of negative ions remain in the glass substrate 9 and silicon A space charge layer is formed on the joint surface with the substrate 8, and a strong attractive force is generated between the silicon substrate 8 and the glass substrate 9, thereby completing the coupling.

[0006]

However, the anodic bonding described above can be used only for bonding glass containing mobile ions such as Pyrex glass to silicon or glass, and the bonding material is extremely limited. There was a problem that would be done. In addition, Pyrex glass is
There is a problem that the cost is higher than that of ordinary glass because the mobile ions Na ⁺ are contained. Furthermore, since the temperature is raised to around 450 ° C. by the hot plate 10, there is a problem that deformation due to heat occurs, and when joining Pyrex glass and silicon,
There is a problem that residual stress is generated after joining due to a difference in linear expansion coefficient.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to reduce the cost without limiting the material, and to process deformation such as deformation due to heating and residual stress. An object of the present invention is to provide a method for bonding substrates, which can eliminate defects.

[0008]

According to the first aspect of the present invention, after forming a plating film on the lower surface of the substrate, through holes are formed in the substrate and at least one other substrate, respectively. The other substrate is placed on the substrate, and plating is formed in the through-hole, whereby the substrate and the other substrate are joined.

According to the second aspect of the present invention, a hole having a bottom is formed in the substrate, the hole having the bottom is buried by plating, and a through hole is formed so as to penetrate the hole having the bottom. The substrate and the other substrate are formed by forming a through hole in at least one other substrate, placing the other substrate on the substrate, and plating the through hole. Are joined.

According to the third aspect of the present invention, after a plating film is formed on the lower surface of the substrate, at least one other substrate is placed on the substrate and the substrate is penetrated by the other substrate. The substrate is bonded to the other substrate by forming a through-hole and plating the through-hole.

According to a fourth aspect of the present invention, after a hole having a bottom is formed in the substrate, the hole having the bottom is buried by plating, and at least one other substrate is mounted on the substrate. Then, a through-hole is formed in the substrate and the other substrate so as to penetrate the hole with the bottom, and plating is formed in the through-hole, so that the substrate and the other substrate are separated from each other. It is characterized by joining.

According to the fifth aspect of the present invention, the first aspect is provided.
The method for bonding substrates according to any one of claims 4 to 5, wherein the through holes are formed by anisotropic wet etching.

In the invention according to claim 6, claim 1 is provided.
In the method of bonding a substrate according to any one of claims 4 to 5, the through hole is formed by generating a magnetic field in addition to RIE (Reactive Ion Etching).

According to the seventh aspect of the present invention, there is provided the first aspect.
5. The method according to claim 4, wherein the through hole is formed by a dicing method.

According to the invention described in claim 8, claim 1 is provided.
In the method for bonding substrates according to any one of claims 7 to 7, plating is performed until hemispherical plating is formed on the opening of the through hole.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A method for bonding substrates according to the present embodiment will be described in detail with reference to FIGS. FIG. 1 is a cross-sectional view illustrating a bonding state of substrates according to the method of bonding substrates according to the present embodiment. FIG.
9 are views showing the first to twenty-fourth steps of the method for bonding substrates according to the present embodiment, and (a), (c), and (e).
Are perspective views, and (b), (d), and (f) are (a),
It is sectional drawing of (c) and (e). As shown in FIG. 1, in the method for bonding substrates according to the present embodiment, a plating introduction hole is formed in the substrates 1 and 6 by anisotropic etching, and the plating introduction hole is plated. This is a method for bonding the substrates 6. Hereinafter, each step for bonding the substrate 1 and the substrate 6 will be described in detail.

First, as shown in FIGS. 2A and 2B,
On a substantially flat substrate 1 having a thickness of about 400 μm,
After a silicon nitride (Si ₃ N ₄ ) film 2 is formed with a thickness of about 1500 Å, a cyclized polyisoprene rubber is formed on the silicon nitride film 2 as shown in FIGS. 2C and 2D. Bisazide compound is converted to xylene (C ₈ H _1
6 ) A negative photoresist 3 made of a solution in an organic solvent is applied so as to have a thickness of about 5 μm. Next, as shown in FIGS. 2E and 2F, a coating 4aa made of a material that does not transmit ultraviolet light, such as nickel chrome.
Is formed on the glass plate 4 according to the size of the plating introduction hole to be drilled later, and the glass substrate 4 is placed on the negative photoresist 3 with the surface on which the coating 4aa is formed facing downward. Place. The negative photoresist 3 is exposed by irradiating ultraviolet rays R from above the glass plate 4, and the glass plate 4 is removed.

Next, by applying tetramethyl ammonium hydroxide ((CH ₃ ) ₄ NOH.5H ₂ O <TMA>) to the negative photoresist 3 at a low concentration, the exposed portion is developed. And FIG.
As shown in (a) and (b), the portion of the negative photoresist 3 covered with the coating 4aa is melted and removed, and an opening 3aa is formed. Then, the substrate 1 is placed in a vacuum device, and the inside of the vacuum device is filled with a reactive gas such as carbon tetrafluoride (CF ₄ ). A fluorine radical (radical) composed of an atom or a molecule active on
By performing RIE (Reactive Ion Etching), which is a kind of dry etching, for generating cations such as F ₃ ⁺ and CF ₂ ⁺ , as shown in FIG. 3C and FIG. The opening 2aa is formed by etching the formed silicon nitride film 2.

Next, a removing solution such as concentrated nitric acid (HNO ₃ ) is applied to the negative photoresist 3, and FIG.
As shown in FIG. 4F, after the negative photoresist 3 is removed, anisotropic etching is carried out, and FIGS.
As shown in (1), a plating introduction hole (hole with a bottom) 1aa is formed so as to have a depth of about half the thickness of the substrate 1. As a method of anisotropic etching, for example, the substrate 1
If the material is silicon or glass, TMA
H or potassium hydroxide (KOH) and ethanol (CH
₃ CH ₂ OH) and isopropyl alcohol ((CH ₃ ) ₂ C
Immersion in an etching solution consisting of an aqueous solution of HOH),
Plating introduction hole 1 by wet etching
aa is drilled.

Next, FIG.
After removing the silicon nitride film 2 as shown in FIG.
As shown in FIGS. 4E and 4F, a nickel film (Ni) 5 is formed on the substantially flat substrate 1. Nickel film 5
As a method of forming, a metal having a high melting point is discharged and melted as an electrode, and the melted particles are sprayed at a high speed on the surface of the material to be plated to form a thin film, or a hot metal vapor is formed in a vacuum, Vacuum deposition, which cools and deposits a metal thin film, introduces a low-pressure gas into a vacuum deposition device, applies an electric field to generate plasma, and forms a thin film while ionizing evaporated particles from an evaporation source. Method.

Then, the substrate 1 is placed in an electrolytic cell (not shown), and an opening is formed in accordance with the opening 5a shown in FIGS. 4 (e) and 4 (f). The nickel film 5 is formed by a mask made of a resin molded product.
As shown in FIGS. 5A and 5B, the upper surface of the nickel film 5 is substantially covered with the nickel film 5 formed on the substrate 1 by applying an electrode and performing electrolytic nickel plating. The openings 5a shown in FIGS. 4E and 4F are buried by nickel plating so as to be uniform, thereby forming a buried portion 5b. Next, a silicon nitride film 2 having a thickness of about 1500 angstroms was formed on one surface.
A substantially flat substrate 6 having a thickness of about m is placed on the substrate 1. At this time, the nickel film 5 of the substrate 1
And the silicon nitride film 2 of the substrate 6
Is placed in contact with the surface on which no is formed.

Next, in the same manner as when the plating introduction hole 1aa is formed, the silicon nitride film 2 is
As shown in (f), the negative photoresist 3 is 5 μm thick.
m, and a coating 4ab of nickel chromium or the like is formed on the glass plate 4 according to the size of the cross-sectional area of the buried portion 5b as shown in FIGS. 6 (a) and 6 (b). Then, the glass substrate 4 having the surface on which the coating 4ab is formed faces downward.
Is placed on the negative photoresist 3. The negative photoresist 3 is exposed by irradiating ultraviolet rays R from above the glass plate 4, and the glass plate 4 is removed.

Next, a low-concentration TMAH is applied to the negative photoresist 3 and the exposed portion is developed, and FIG.
As shown in (c) and (d), the negative photoresist 3 in the unexposed area covered with the coating 4ab is melted and removed, and an opening 3ab is formed. Then, by performing RIE, as shown in FIGS. 6E and 6F, the silicon nitride film 2 exposed from the opening 3ab is etched to form the opening 2ab. Next, as shown in FIGS. 7A and 7B, after removing the negative photoresist 3 by applying concentrated nitric acid or the like, the substrate 6 on which the silicon nitride film 2 is formed, and the nickel film 5 The above-mentioned wet etching is performed while keeping the substrate 1 on which is formed, as shown in FIGS. 7C and 7D,
Plating introduction holes (through holes) 1ab and 6a are formed.

FIG. 7 (e) shows a state in which
After removing the silicon nitride film 2 as shown in FIG.
With the substrate 6 and the substrate 1 kept in contact with each other, the substrate 6 is placed in an electrolytic cell (not shown), and the nickel film 5 formed on the substrate 1 is formed.
And nickel plating is formed in the plating introduction holes 1ab and 6b. At this time, when the plating is formed up to the vicinity of the opening of the plating introduction hole 1a, the plating is not terminated but nickel plating is performed as shown in FIG.
As shown in (a) and (b), plating is continued until a hemispherical retaining portion 5ca is formed, which is formed on the substrate 6 and extends around the opening of the plating introduction hole 1a.

Then, as shown in FIGS. 8C and 8D, a positive photoresist 7 made of a novolak dissolved in an organic solvent is formed on the nickel film 5 of the substrate 1 and then nickel chromium is formed. A material that does not transmit ultraviolet light, such as the plating introduction holes 1ab and 6 shown in FIGS.
8 (e) and 8 (f), a coating 4b having an area larger than the opening area is formed as shown in FIGS.
The glass plate 4 is formed on the lower end of the glass plate 4, and the glass plate 4 is placed on the positive photoresist 7. Thereafter, the glass plate 4 is removed by irradiating ultraviolet rays R from above the glass plate 4 to expose the positive photoresist 7 in a portion not covered by the coating 4b.

Next, by applying a low concentration of TMAH to the positive photoresist 7, the exposed portion is developed and covered with a coating 4b as shown in FIGS. 9 (a) and 9 (b). Of the positive photoresist 7a
Remains. In this state, nitric acid, hydrochloric acid (HCl),
By applying a removing solution such as a copper aqueous solution (CuCl ₂ .2H ₂ O) for removing nickel, as shown in FIGS. 9C and 9D, a portion other than the portion covered with the positive photoresist 7a , The nickel film 5 is removed. Next, by removing the positive type photoresist 7a with a removing solution such as concentrated nitric acid or the like, a portion of the nickel film 5 covered with the positive type photoresist 7a remains, and FIGS. 9 (e) and 9 (f).
The joining is completed as shown.

When the above-mentioned wet etching is performed, strictly speaking, the plating introduction hole 1a having a substantially tapered longitudinal sectional view.
a, 1ab and 6a are formed, and depending on the thickness of the substrates 1 and 6, it may not be possible to penetrate them. In such a case, the plating introduction holes 1aa, 1ab, 6a may be formed by drilling from both sides of the substrates 1, 6. Further, the numerical examples described above are merely examples, and the present invention is not limited to these examples.

Furthermore, although the description has been made assuming that the etching solution used for the wet etching is an aqueous solution of sodium hydroxide or TMAH, and ethanol and isopropyl alcohol, the present invention is not limited to this combination. Further, the present invention can be applied to silicon nitride, polysilicon, and the like by changing the etching solution. on the other hand,
Although it has been described that carbon tetrafluoride is used as a reactive gas used in RIE, the present invention is not limited to this.
For example, carbon tetrachloride (CCl ₄ ) may be used.

[Second Embodiment] In the first embodiment, the plating introduction hole 1a is formed by wet etching.
a, 1ab and 6a. On the other hand, in the present embodiment, the plating introduction hole 1a is formed by DEEP-RIE.
a, 1ab and 6a are drilled. What is DEEP-RIE?
As a material of the substrate 1 and the substrate 6, silicon, glass, silicon nitride (Si ₃ N ₄ ), aluminum (Al) or the like is used, and a reactive gas such as carbon tetrafluoride (CF ₄ ) is filled in a vacuum. , Applying high frequency power to generate plasma,
By generating fluorine free radicals (radicals) composed of chemically active atoms and molecules and cations such as CF ₃ ⁺ and CF ₂ ^+, and generating a magnetic field by passing a current through a coil or the like, This is an anisotropic etching method that enables deeper etching. Further, by using DEEP-RIE, the step of forming the silicon nitride film 2 used in the first embodiment becomes unnecessary.

Hereinafter, the method of bonding substrates according to the present embodiment will be described with reference to FIGS. 4, 5A, 5B, 7E, 7F,
This will be described in detail with reference to FIGS. FIGS. 10 to 12 are diagrams showing first to fourth and ninth to eleventh procedures of the method for bonding substrates according to the present embodiment.
(C) and (e) are perspective views, and (b), (d) and (f) are cross-sectional views of (a), (c) and (e), respectively. The description of the same parts as those in the method described in the first embodiment will be omitted or simplified.

First, as shown in FIGS. 10 (a) and 10 (b), a negative type photoresist 3 is applied on the substrate 1 and then, as shown in FIGS. Is formed on the glass plate 4 in accordance with the size of the plating introduction hole to be formed, and the glass substrate 4 is placed on the negative photoresist 3 with the surface on which the coating 4aa is formed facing downward. Place on top. The negative photoresist 3 is exposed by irradiating ultraviolet rays R from above the glass plate 4, and the glass plate 4 is removed. Next, FIG.
As shown in (f), the negative photoresist 3 is developed, the portion of the negative photoresist 3 covered with the coating 4aa is removed, and an opening 3aa is formed.

Then, DEEP-RIE is performed, and FIG.
As shown in FIGS. 1A and 1B, a plating introduction hole 1aa is formed so as to have a depth of about half of the thickness of the substrate 1. Next, as shown in FIGS. 4C and 4D, the negative photoresist 3 is removed by using concentrated nitric acid or the like, and then, using a method such as sputtering, vacuum deposition, or ion plating, as shown in FIG. As shown in (e) and (f), a nickel film 5 is formed on the substantially flat substrate 1.

Then, the substrate 1 is placed in an electrolytic cell (not shown), and the nickel film 5 formed on the substrate 1 is provided with an electrode and a mask having an opening corresponding to the opening 5a. Then, electrolytic nickel plating was performed, and FIG.
As shown in FIG. 4B, the opening 5a of the nickel film 5 shown in FIGS. 4E and 4F is buried by nickel plating so as to be substantially uniform with the upper surface of the nickel film 5, and the buried portion 5b is formed. To form Next, as shown in FIGS. 11C and 11D, a negative photoresist 3 is applied on the substrate 6, and the silicon nitride film 2 is formed on the substrate 1 with the nickel film 5 turned upside down.
The substrate 6 is placed with the side facing upward.

Next, as shown in FIGS. 11 (e) and 11 (f), a coating 4ab of nickel chromium or the like is formed on the glass plate 4 according to the size of the cross-sectional area of the buried portion 5b. With the surface on which the 4ab is formed facing downward, the glass substrate 4
Is placed on the negative photoresist 3. The negative photoresist 3 is exposed by irradiating ultraviolet rays R from above the glass plate 4, and the glass plate 4 is removed. Next, as shown in FIGS. 12A and 12B, the negative photoresist 3 is developed, and the portion of the negative photoresist 3 covered with the coating 4ab is removed to form an opening 3ab. I do.

Then, as shown in FIGS. 7E and 7F, after the negative photoresist 3 is removed, the substrate 6 is kept in contact with the substrate 1 in an electrolytic bath (not shown). At the same time, the electrodes are attached to the nickel film 5 formed on the substrate 1 and electrolytic nickel plating is performed. At this time, in the same manner as in the first embodiment, when the plating is formed up to the vicinity of the opening of the plating introduction hole 1a, the plating is not terminated, but the nickel plating is performed as shown in FIGS. As shown in b), the substrate 6 around the opening of the plating introduction hole 1a.
A hemispherical retaining portion 5ca formed so as to extend upward.
Continue the plating until the formation is completed.

Then, as shown in FIGS. 8C and 8D, the bonded substrate 1 and the substrate 6 are turned over, and a positive photoresist 7 is formed on the nickel film 5. A material that does not transmit ultraviolet light, such as, for example, is fitted to the openings of the plating introduction holes 1ab and 6a, and a coating 4b having an area larger than the opening area is formed on the lower end of the glass plate 4, and FIG. As shown in (f), the glass plate 4 is placed on the positive photoresist 7. afterwards,
The glass plate 4 is removed by irradiating ultraviolet rays R from above the glass plate 4 to expose the positive photoresist 7.

Next, the positive photoresist 7 is developed to leave a portion of the positive photoresist 7a covered with the coating 4b as shown in FIGS. 9A and 9B. In this state, by applying a removing solution for removing nickel, as shown in FIGS. 9C and 9D, the nickel film 5 other than the portion covered with the positive photoresist 7a is removed. Next, a positive photoresist 7a
Is removed with a removing solution, so that the nickel film 5 in the portion covered with the positive photoresist 7a remains, and the bonding is completed as shown in FIGS. 9 (e) and 9 (f).

Although it has been described that carbon tetrafluoride is used as a reactive gas used in DEEP-RIE, the present invention is not limited to this. For example, carbon tetrachloride (CC
l ₄ ) may be used. In the first and second embodiments described above, the plating introduction hole 1aa has been described as being formed so as to have a thickness of about half the thickness of the substrate 1, but the present invention is not limited to this. It is sufficient if the thickness does not hinder the subsequent nickel plating process.

When the thickness of the substrate 1 and the thickness of the substrate 6 are small, FIGS. 2 to 4, FIGS.
(B), a plating introduction hole 1aa is formed in the substrate 1;
The lower surface of the substrate 1 is plated without performing the step of forming the buried portion 5b by plating the plating introduction hole 1aa, and anisotropic wet etching or DEEP-RIE is performed from the upper surface of the substrate 6. By doing so, the plating introduction holes 1aa, 1ab, 6a may be formed at a time to perform plating.

As shown in FIGS. 5C and 5D,
Although it has been described that the nickel film 5 is formed on the substrate 1 and then the substrate 6 is placed on the substrate 1, the present invention is not limited to this. For example, the nickel film 5 is formed on the substrate 1, respectively. The substrate 6 may be mounted on the substrate 1 after the silicon nitride film 2 having the opening 2ab formed in the substrate 6 is formed. Furthermore, although the plating introduction hole 1ab of the substrate 1 and the plating introduction hole 6b of the substrate 6 have been described as being formed at once, they may be separately drilled, or the substrate may be formed on the substrate 1 after the drilling process. 6 may be placed.

[Third Embodiment] Next, plating introduction grooves 1b and 6b corresponding to the plating introduction holes 1aa, 1ab and 6a described in the first embodiment are pierced by a dicing saw. A method of joining substrates, wherein the plating introduction grooves 1b and 6b are joined to the substrate 6 by plating, will be described in detail with reference to FIGS. 13 to 15 are diagrams showing first to eighth procedures of the method for bonding substrates according to the present embodiment.
(A), (c), (e), (g) are perspective views, (b),
(D), (f), and (h) are (a), (c),
It is sectional drawing of (e) and (g). The description of the same parts as those in the first embodiment will be omitted or simplified, and the characteristic parts of the present embodiment will be described in detail.

First, the substrate 1 was formed by a method such as electrolytic plating, sputtering, vacuum deposition, or ion plating.
13A, a nickel film 5 is formed on the lower surface of FIG.
As shown in (b), the substrate 6 is placed so as to overlap the substrate 1. Next, using a dicing machine, a dicing saw made of a thin diamond whetstone that rotates at high speed,
As shown in FIGS. 13 (c) and 13 (d), the plating introduction groove 1 is formed so that the vicinity of the periphery of the substrate 6 and the substrate 1 is substantially lattice-shaped.
Drill b and 6b.

Next, while the substrate 6 and the substrate 1 are kept in contact with each other, the substrate 6 is placed in an electrolytic bath (not shown), and an electrode is attached to the nickel film 5 formed on the substrate 1. Perform plating. At this time, similarly to the first embodiment, when the plating is formed up to the vicinity of the opening of the plating introduction groove 1b, instead of terminating the plating process, electrolytic nickel plating is performed as shown in FIGS. As shown in (f), the plating is continued until the hemispherical retaining portion 5cb is formed, which extends over the substrate 6 around the opening of the plating introduction groove 1b and is formed.

Then, as shown in FIGS. 14A and 14B, the combined substrate 6 and the substrate 1 are turned over and a positive photoresist 7 is formed on the nickel film 5 and then nickel chromium is formed. A material that does not transmit ultraviolet light is adjusted to the positions of the plating introduction grooves 1b and 6b, and a coating 4c having an area larger than the opening area is formed at the lower end of the glass plate 4, and FIGS. As shown in d), the glass plate 4 is placed on the positive photoresist 7. Thereafter, the positive photoresist 7 is exposed by irradiating ultraviolet rays R from above the glass plate 4, and the glass plate 4 is removed.

Next, by applying a low concentration of TMAH to the positive photoresist 7, the exposed portion is developed, and as shown in FIGS. 14 (e) and (f), the coating 4c is formed.
Positive photoresist 7 covered with
b remains. In this state, a removing solution for removing nickel is applied to remove the nickel film 5 other than the portion covered with the positive photoresist 7b as shown in FIGS. 15 (a) and 15 (b). Next, the positive type photoresist 7b is removed by a removing solution, so that FIGS.
As shown in FIG. 7, the nickel film 5 in the portion covered with the positive photoresist 7a remains, and the bonding is completed.

In the first to third embodiments described above, electrolytic nickel plating is described. However, it is sufficient that plating can be performed, and chemical plating may be used. Further, although the description has been made assuming that the nickel film 5 is formed, the metal is not limited to nickel as long as the metal can be plated.
Gold plating may be used.

[0047]

As described above, in the invention according to any one of claims 1 to 4, there is no need to limit the material of the substrate to be bonded unlike the conventional anodic bonding, etc. Since special glass is not used unlike in the above case, the cost for bonding the substrates can be reduced. Further, since it is not necessary to heat the substrate to be joined to a high temperature, there is no deformation of the substrate due to heat, and when joining substrates of different materials, there is a remarkable effect that no residual stress is generated after joining.

According to the second or fourth aspect of the present invention, a hole with a bottom (plating introduction hole) is formed in the substrate, and the hole with the bottom is buried by plating (forming a buried portion). Therefore, the substrate is thick, and a through hole (plating introduction hole) cannot be formed only from one side of the substrate, and the substrate can be bonded even when the through hole is formed from both sides of the substrate. It works.

According to the third or fourth aspect of the present invention, when a through hole (plating introduction hole) is formed by etching, a coating film for etching is not formed on each substrate. In addition, since a coating film for etching is formed only on the upper surface of another substrate and a through-hole can be formed at a time, an effect of improving productivity is achieved.

In the invention according to claim 5, claim 1 is
In addition to the effects of the invention according to any one of claims 4 to 9, a large amount of through holes (plating introduction holes) can be formed at once by performing anisotropic wet etching.
This has the effect of improving productivity.

In the invention according to claim 6, claim 1 is
In addition to the effects of the invention according to any one of claims 4 to 7, since a through-hole (plating introduction hole) is formed by performing RIE by generating a magnetic field, a highly accurate through-hole can be formed. There is an effect that accurate joining can be provided.

In the invention according to claim 7, claim 1 is
In addition to the effects of the present invention, through holes (plating introduction holes) are easily and quickly formed as compared with a method of performing RIE by generating anisotropic wet etching and a magnetic field. Therefore, there is an effect that productivity is improved.

In the invention according to claim 8, claim 1 is
In addition to the effect of the invention according to any one of claims 7 to 7, plating is performed until hemispherical plating (retaining portion) is formed in the opening of the through hole (plating introduction hole), so that the plating acts like a rivet. Therefore, an effect that the user can be surely contacted is achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a bonding state of substrates according to a method of bonding substrates according to a first embodiment.

FIGS. 2A to 2C are diagrams showing first to third procedures of the method for bonding substrates according to the first embodiment, wherein FIGS. 2A, 2C, and 2E are perspective views, and FIGS. ), (F) are (a),
It is sectional drawing of (c) and (e).

FIGS. 3A to 3C are views showing fourth to sixth procedures of the method for bonding substrates according to the first embodiment, wherein FIGS. 3A, 3C, and 3E are perspective views, and FIGS. ), (F) are (a),
It is sectional drawing of (c) and (e).

FIGS. 4A to 4C are diagrams showing seventh to ninth procedures of the method for bonding substrates according to the first embodiment, wherein FIGS. 4A, 4B and 4E are perspective views, FIGS. ), (F) are (a),
It is sectional drawing of (c) and (e).

FIGS. 5A to 5C are views showing tenth to twelfth procedures of the substrate bonding method according to the first embodiment, wherein FIGS.
(E) is a perspective view, and (b), (d), and (f) are cross-sectional views of (a), (c), and (e), respectively.

FIGS. 6A to 6C are views showing thirteenth to fifteenth procedures of the method for bonding substrates according to the first embodiment; FIGS.
(E) is a perspective view, and (b), (d), and (f) are cross-sectional views of (a), (c), and (e), respectively.

FIGS. 7A to 7C are views showing sixteenth to eighteenth procedures of the method for bonding substrates according to the first embodiment, wherein FIGS.
(E) is a perspective view, and (b), (d), and (f) are cross-sectional views of (a), (c), and (e), respectively.

FIGS. 8A to 8C are views showing nineteenth to twenty-first procedures of the method for bonding substrates according to the first embodiment; FIGS.
(E) is a perspective view, and (b), (d), and (f) are cross-sectional views of (a), (c), and (e), respectively.

FIGS. 9A to 9C are views showing the 22nd to 24th procedures of the method for bonding substrates according to the first embodiment, wherein FIGS.
Are perspective views, and (b), (d), and (f) are (a),
It is sectional drawing of (c) and (e).

FIGS. 10A to 10C are diagrams showing first to third procedures of the method for bonding substrates according to the second embodiment, wherein FIGS.
Are perspective views, and (b), (d), and (f) are (a),
It is sectional drawing of (c) and (e).

FIG. 11 shows a fourth method of joining substrates according to the second embodiment;
It is a figure which shows a 9th, 10th procedure, (a), (c),
(E) is a perspective view, and (b), (d), and (f) are cross-sectional views of (a), (c), and (e), respectively.

FIG. 12 illustrates an eleventh embodiment of the method for bonding substrates according to the second embodiment.
3A is a perspective view, and FIG. 3B is a cross-sectional view of FIG.

FIGS. 13A to 13C are diagrams showing first to third procedures of the method for bonding substrates according to the third embodiment, wherein FIGS.
Are perspective views, and (b), (d), and (f) are (a),
It is sectional drawing of (c) and (e).

FIGS. 14A to 14C are diagrams illustrating fourth to sixth procedures of the method for bonding substrates according to the third embodiment, wherein FIGS.
Are perspective views, and (b), (d), and (f) are (a),
It is sectional drawing of (c) and (e).

FIG. 15 is a cross-sectional view of a seventh embodiment of the substrate bonding method according to the third embodiment;
It is a figure which shows the 8th procedure, (a), (c) is a perspective view,
(B), (d) is sectional drawing of (a), (c), respectively.

16A is a cross-sectional view illustrating a configuration of a semiconductor pressure sensor, and FIG. 16B is a cross-sectional view illustrating anodic bonding of the semiconductor pressure sensor.

[Description of Signs] 1 Substrate 1aa Plating introduction hole (through hole, bottomed hole) 1ab Plating introduction hole (through hole) 1b Plating introduction groove (through hole) 5 Nickel plating film (plating film) 5ca Retainer (hemisphere) 5cb Retaining portion (hemispherical plating) 6 Substrate (at least one other substrate) 6a Plating introduction hole (through hole) 6b Plating introduction groove (through hole)

Claims (8)

[Claims] After forming a plating film on a lower surface of a substrate, a through hole is formed in each of the substrate and at least one other substrate, and the other substrate is mounted on the substrate. A method of joining substrates, comprising joining the substrate and the other substrate by forming plating in the through holes. 2. A hole having a bottom is formed in the substrate, the hole having the bottom is buried by plating, and a through hole is formed so as to penetrate the hole having the bottom, and at least one other hole is formed. Forming a through hole in one of the substrates, placing the other substrate on the substrate, and plating the through hole to join the substrate and the other substrate. Substrate bonding method. 3. After forming a plating film on the lower surface of the substrate, another at least one substrate is placed on the substrate, and a through-hole penetrating the substrate and the other substrate is formed. A method of joining substrates, comprising joining the substrate and the other substrate by forming plating in the through holes. 4. After drilling a hole with a bottom in the substrate, the hole with the bottom is buried by plating, another at least one substrate is placed on the substrate, and a hole is formed in the hole with the bottom. A through hole is formed in the substrate and the other substrate so as to penetrate, and plating is formed in the through hole, thereby joining the substrate and the other substrate. Joining method. 5. The method according to claim 1, wherein the through hole is formed by anisotropic wet etching. 6. The method according to claim 6, wherein the through hole is formed by RIE (Reactive Ion E
5. The method according to claim 1, wherein the perforation is performed by generating a magnetic field in addition to the tching. 7. The method according to claim 1, wherein the through holes are formed by a dicing method. 8. The method according to claim 1, wherein plating is performed until hemispherical plating is formed in the opening of the through hole.