JP2010221573A - Manufacturing method of multilayer substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a multilayer substrate capable of skipping alignment of holes of multiple substrates for sticking as well as forming a high precision, high quality shaped hole inside the substrate, when producing the multilayer substrate by sticking a plurality of substrates. <P>SOLUTION: The manufacturing method of the multilayer substrate composed by sticking a plurality of substrates including steps 1-3 as described hereinafter; provided that the plurality of substrates includes a combination of a first substrate and a second substrate different at least in etching characteristic. In step 1 a first modified part is formed by irradiating a laser beam along a route where the first hole of the first substrate will be formed so that the core of first substrate may be modified. In step 2 a second modified part is formed by irradiating a laser beam along a route where the second hole of the second substrate will be formed so that the core of second substrate may be modified. In step 3 the first hole and the second hole are formed by etching the first modified part and the second modified part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a multilayer substrate in which a plurality of substrates are bonded together.

Conventionally, a method for processing a single crystal substrate is known (see, for example, Patent Document 1).
This processing method forms a through hole in a predetermined path in a substrate made of a single crystal material, and includes the following first step and second step.
In the first step, the substrate is irradiated with laser light, and the material is altered along a predetermined path to form a material altered portion. In the second step, the material altered portion is etched to form a through hole in a predetermined path.

Patent Document 1 describes a case where a plurality of single crystal substrates are stacked and irradiated with laser light in the first step as an example for shortening the time required for rearranging the single crystal substrates in the first step. Has been.
By the way, it is a multi-layer substrate formed by laminating a plurality of substrates such as single crystal substrates, each of the plurality of substrates having a desired hole, and the shape and direction of each hole is different for each substrate. May be different.

When manufacturing such a multilayer substrate, a conventional processing method can be applied to the formation of each hole in each substrate. However, the conventional processing method cannot always form a hole with high accuracy and high quality inside each substrate. In addition, in the case of a multilayer substrate, it is necessary to align each hole in each substrate when bonding a plurality of substrates in which holes are formed.
For this reason, when manufacturing a multilayer substrate composed of a plurality of substrates bonded together, it is possible to form a hole with high accuracy and high quality inside the substrate, and to form holes for bonding a plurality of substrates together. It is desirable that alignment is not necessary.

JP 2005-74663 A

  Therefore, the purpose of some aspects of the present invention is to form a high-precision, high-quality hole in the substrate when manufacturing a multilayer substrate formed by laminating a plurality of substrates. It is an object of the present invention to provide a method for manufacturing a multilayer substrate that does not require the alignment of holes when the substrates are bonded together.

In order to solve the above problems and achieve the object of the present invention, each aspect of the present invention is configured as follows.
A first aspect of the present invention is a method for manufacturing a multilayer substrate comprising a plurality of substrates bonded together, wherein the plurality of substrates is a combination of at least a first substrate and a second substrate having different etching characteristics. A first step of forming a first altered portion by altering the inside of the first substrate by irradiating a laser beam along a path in which the first hole of the first substrate is formed. And a second step of irradiating a laser beam along a path in which the second hole of the second substrate is formed to alter the inside of the second substrate to form a second altered portion. And a third step of etching the first altered portion and the second altered portion, respectively, to form the first hole and the second hole, respectively.

According to a second aspect of the present invention, in the first aspect, the plurality of substrates are different from the first substrate having at least different etching characteristics according to the direction or shape of each hole obtained by etching each substrate. It consists of a combination with two substrates.
According to a third aspect of the present invention, in the first or second aspect, the bonding of the plurality of substrates is performed prior to the first step, or between the second step and the third step. Do.
According to a fourth aspect of the present invention, in any one of the first to third aspects, the combination of the plurality of substrates is at least one of a single crystal silicon substrate, a glass substrate, a quartz substrate, a quartz substrate, and a polycrystalline substrate. A combination of the two.

According to a fifth aspect of the present invention, in any one of the first to third aspects, the combination of the plurality of substrates is two single crystal silicon substrates having different etching characteristics, one of which has a plane orientation (110). It is a silicon substrate, and the other is a silicon substrate having a plane orientation (100).
According to the aspect of the present invention having such a configuration, when manufacturing a multilayer substrate formed by laminating a plurality of substrates, high-precision and high-quality holes can be formed inside the substrate. It is not necessary to align holes when aligning the substrates.

It is a figure explaining the process of the manufacturing method of 1st Embodiment of this invention. It is sectional drawing of the multilayer substrate created with the manufacturing method of the 1st Embodiment. It is sectional drawing of the other multilayer substrate created with the manufacturing method of the 1st Embodiment. It is a top view of the multilayer substrate (relay substrate) created with the manufacturing method of 2nd Embodiment of this invention. It is sectional drawing of the XX line of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram for explaining the steps of the manufacturing method according to the first embodiment of the present invention.
1st Embodiment of this invention is a manufacturing method of the multilayer substrate comprised by bonding together several board | substrates, Comprising: The several board | substrate consists of the combination of two board | substrates from which an etching characteristic differs at least. More specifically, the plurality of substrates are a combination of at least two substrates having different etching characteristics according to the direction or shape of each hole obtained by etching each substrate.

Next, the manufacturing method of 1st Embodiment is demonstrated with reference to FIG.
As shown in FIG. 1, the multilayer substrate manufactured by the manufacturing method of the first embodiment has a three-layer structure in which three silicon substrates 1 to 3 are bonded, and each layer is etched after laser irradiation. The etching characteristics of the direction or shape of each hole to be obtained are optimal, and a material for selecting the hole with high accuracy and high quality is selected.
In this example, a single crystal having a plane orientation (110) whose etching characteristics of the vertical holes are optimum for the silicon substrates 1 and 3 in which holes (hereinafter referred to as vertical holes) need to be formed inside are perpendicular to the substrate surface. A silicon substrate is used. On the other hand, the silicon substrate 2 that needs to form a horizontal hole (hereinafter referred to as a horizontal hole) inside the substrate surface uses a single crystal silicon substrate having a plane orientation (100) in which the etching characteristics of the horizontal hole are optimal. .

  First, the silicon substrates 1 to 3 are bonded together. As shown in FIG. 1A, the silicon substrates 2 are bonded together with the silicon substrates 1 and 3 sandwiched therebetween. Various known joining methods are used for this bonding. The adhesive used for bonding at this time may be one having a property of transmitting laser light. Moreover, you may make it stick directly by surface active joining, without using an adhesive agent.

Next, as shown in FIG. 1A, etching protective films 4 and 5 for protecting from etching are formed on the back surface of the silicon substrate 1 and the front surface of the silicon substrate 3 bonded as described above. The etching protection films 4 and 5 may be any film that does not elute when the silicon substrates 1 and 3 are etched and has laser beam transparency. As the etching protection films 4 and 5, silicon oxide (SiO ₂ ), silicon nitride (SiN), or the like is used.
Next, in order to form the vertical hole 6 at a predetermined position inside the silicon substrate 1, the laser beam 9 is irradiated along a path (direction) 10 in which the vertical hole 6 is formed (see FIG. 1B). . The laser beam 9 is irradiated by condensing the laser beam 9 using a lens and scanning (moving) the focal point along a path 10 in which the vertical hole 6 is formed.

Next, in order to form the horizontal hole 7 at a predetermined position inside the silicon substrate 2, the laser beam 9 is irradiated along the path 11 in which the horizontal hole 7 is formed. Subsequently, in order to form the vertical hole 8 at a predetermined position inside the silicon substrate 3, the laser beam 9 is irradiated along the path 12 in which the vertical hole 8 is formed.
Thereafter, when the irradiation (scanning) with the laser beam 9 is completed, as shown in FIG. 1C, the silicon substrate 1 to 3 are altered into a portion (region) where the vertical hole 6, the horizontal hole 7, and the vertical hole 8 are formed. Parts 13 to 15 are formed, respectively.

Here, the altered portions 13 to 15 formed in the silicon substrates 1 to 3 are altered due to, for example, the density, refractive index, mechanical strength, and other physical characteristics of the silicon substrates 1 to 3 being different from the surroundings. The part that can be easily removed by etching.
As long as the altered portions 13 to 15 can be formed in the silicon substrates 1 to 3, various laser beams 9 can be adopted. As an example of the laser beam 9 described above, a near-infrared laser beam that is transmissive to silicon is used. For example, YAG laser light and VYO4 laser light having a wavelength of 1064 [nm], and YLF laser light having a wavelength of 1046 [nm] are used.

Next, the silicon substrates 1 to 3 are etched under a predetermined etching condition (time, temperature, concentration) using a predetermined etching solution, and the portions related to the altered portions 13 to 15 are removed. The vertical hole 6, the horizontal hole 7, and the vertical hole 8 are respectively formed inside 1 to 3 (see FIG. 1D).
Here, as the silicon substrates 1 and 3, a single crystal silicon substrate having a plane orientation (110) having optimum etching characteristics when the vertical holes 6 and 8 are formed therein by etching is used. For this reason, when etching the altered portions 13 and 15 in which the vertical holes 6 and 8 are formed, the etching proceeds in the length direction of the altered portions 13 and 15, while the altered portion is altered in the direction perpendicular to the length direction. When a portion that is not present appears, etching stops there.

On the other hand, the silicon substrate 2 is a single crystal silicon substrate having a plane orientation (100) having optimum etching characteristics when the lateral hole 7 is formed therein by etching. For this reason, when etching the altered portion 14 in which the lateral hole 7 is formed, the etching proceeds in the length direction of the altered portion 14, and a portion that is not altered appears in a direction perpendicular to the length direction. Then, the etching stops.
Therefore, the vertical holes 6 and 8 having high-precision and high-quality shapes can be created inside the silicon substrates 1 and 3 by making use of the etching characteristics of the silicon substrate having the plane orientation (110). Similarly, it is possible to create a highly accurate and high-quality lateral hole 7 inside the silicon substrate 2 by utilizing the etching characteristics of the silicon substrate. As a result, it is possible to create a through-hole composed of the vertical hole 6, the horizontal hole 7, and the vertical hole 8 having a high-precision and high-quality shape inside the multilayer substrate to which the silicon substrates 1 to 3 are bonded.
As the etching solution, for example, a potassium hydroxide solution (KOH solution) is used, but it is sufficient that the silicon substrates 1 to 3 can be etched.

Next, the etching protection films 4 and 5 formed on the silicon substrates 1 and 3 are removed as necessary (see FIG. 1E), whereby the multilayer substrate according to the first embodiment is completed.
As described above, in the first embodiment, the vertical holes and the horizontal holes are formed by taking advantage of the difference in etching characteristics (anisotropic etching) of the silicon substrates 1 to 3, so that the vertical holes having a high accuracy and high quality are formed. Lateral holes can be created, and finally desired holes having high-precision and high-quality shapes can be created.

In the first embodiment, the silicon substrates 1 to 3 are bonded together in advance, and holes are formed in the silicon substrates 1 to 3 to form one hole as a whole. For this reason, it is not necessary to align the holes required when holes are made in each of the plurality of substrates and the substrates are then bonded together.
Therefore, according to the first embodiment, when manufacturing a multilayer substrate formed by bonding a plurality of silicon substrates, a highly accurate and high-quality hole can be formed inside the silicon substrate, and a plurality of holes can be formed. It is not necessary to align the holes when bonding the silicon substrates.

(Modification of the first embodiment)
According to the manufacturing method of the first embodiment, a multilayer substrate as shown in FIG. 1 (D) or (E) can be manufactured, and a multilayer substrate as shown in FIGS. 2 and 3 can be manufactured.
Therefore, as a modification of the first embodiment, a method for manufacturing the multilayer substrate shown in FIGS. 2 and 3 will be described.
(1) The multilayer substrate of FIG. 2 has the same basic configuration as the multilayer substrate shown in FIG. 1 (D), but the lateral hole 7 formed in the silicon substrate 2 is replaced with a silicon substrate in the multilayer substrate of FIG. The inclined hole 7A is inclined 45 degrees with respect to the second substrate surface.

Here, in order to form the inclined hole 7A inclined by 45 degrees with respect to the substrate surface of the silicon substrate 2, if the thickness of the silicon substrate 2 is d, it is necessary to set d = L. Here, L is the distance from the center in the length direction of the vertical hole 6 to the center in the length direction of the vertical hole 8 (see FIG. 2).
Further, in the multilayer substrate of FIG. 2, the thickness of the silicon substrate 2 is such that one end side of the vertical holes 6 and 8 of the silicon substrates 1 and 3 is connected to both sides of the inclined hole 7A so that through holes can be formed with high accuracy as a whole. It is necessary to set the hole displacement amount and the hole direction.
The multilayer substrate manufacturing method of FIG. 2 having such a configuration can use the multilayer substrate manufacturing method of the first embodiment shown in FIG. 1 except for the following points.

That is, in the step of irradiating the laser beam 9, in order to form the inclined hole 7A at a predetermined position inside the silicon substrate 2, the laser beam 9 is irradiated along the path where the inclined hole 7A is formed. Become. By this irradiation with the laser light 9, the portion where the inclined hole 7A is formed becomes an altered portion (corresponding to the altered portion 14 of the lateral hole 7 in FIG. 1C).
Further, in the etching process, when the altered portion where the inclined hole 7A is formed is etched, the etching proceeds in the length direction of the altered portion, and the portion that is not altered in the direction perpendicular to the length direction. When appears, the etching stops there. This is because a silicon substrate having a plane orientation (100) having optimum etching characteristics for forming the inclined hole 7A is used as the silicon substrate 2.

(2) The multilayer substrate of FIG. 3 is configured by bonding silicon substrates 1 and 2 together, forming vertical holes 6A and 6B inside the silicon substrate 1 and forming horizontal holes 7B inside the silicon substrate 2, respectively. 6A, the horizontal hole 7B, and the vertical hole 6B are connected to form a U-shaped through hole.
The multilayer substrate manufacturing method of FIG. 3 having such a configuration can be used as it is in the method of manufacturing the multilayer substrate of the first embodiment shown in FIG.

(Second Embodiment)
The manufacturing method according to the second embodiment of the present invention is a case where a relay substrate (rearranged wiring substrate for semiconductor devices) 20 as shown in FIGS. 4 and 5 is manufactured as a multilayer substrate.
As shown in FIGS. 4 and 5, the relay substrate 20 is configured by bonding three silicon substrates 1 to 3 together. The silicon substrates 1 and 3 use a silicon substrate having a plane orientation (110) in which the etching characteristics of the vertical holes are optimal in order to form the vertical holes therein. On the other hand, the silicon substrate 2 uses a silicon substrate having a plane orientation (100) in which the etching characteristics of the lateral hole are optimal in order to form the lateral hole therein.

The relay substrate 20 has a plurality of vertical holes 21 formed at predetermined positions on the silicon substrate 1, a plurality of horizontal holes 22 formed at predetermined positions on the silicon substrate 2, and a plurality of vertical holes 21 formed at predetermined positions on the silicon substrate 3. A vertical hole 23 is formed. The plurality of vertical holes 21, horizontal holes 22, and vertical holes 23 are connected to predetermined vertical holes 21, horizontal holes 22, and vertical holes 23.
Further, a plating layer 25 is formed on the inner peripheral surface of each of the vertical hole 21, the horizontal hole 22, and the vertical hole 23 via an insulating film 24, and the vertical hole 21, the horizontal hole 22, and the vertical hole 23 as a whole are front and back of the relay substrate 20. Is formed (see FIG. 5) .

The manufacture of the relay substrate having such a configuration is performed by adding the following steps based on the manufacturing method of the multilayer substrate according to the first embodiment shown in FIG.
That is, the vertical holes 21, the horizontal holes 22, and the vertical holes 23 are formed in the silicon substrates 1 to 3 by the same method as the manufacturing method of the multilayer substrate of the first embodiment (see FIGS. 1A to 1D), and further below This process has been added.
First, the insulating films 24 are formed in the vertical holes 21, the horizontal holes 22, and the vertical holes 23, respectively.
Next, a plating layer 25 made of a predetermined metal is formed on the insulating film 24 by electroless plating or the like. Next, if the etching protective film (corresponding to the etching protective films 4 and 5 in FIG. 1D) formed on the silicon substrates 1 and 3 is removed, the relay substrate 20 shown in FIGS. 4 and 5 can be obtained. .

(Other embodiments, etc.)
(1) In each of the embodiments described above, the silicon substrates 1 to 3 are bonded in advance prior to the irradiation of the laser beam, and the bonded silicon substrates 1 to 3 are irradiated with the laser beam. However, in the present invention, before the silicon substrates 1 to 3 are bonded together, each silicon substrate is irradiated with laser light, and then the silicon substrates 1 to 3 are bonded together, and the bonded silicon substrates 1 to 3 are bonded to each other. Etching may be performed on the substrate. Even if it does in this way, the effect similar to 1st Embodiment is acquired.

(2) In each of the above embodiments, the single crystal silicon substrate having the plane orientation (110) and the single crystal silicon substrate having the plane orientation (100) are selected as the substrates having different etching characteristics. However, in the present invention, at least two of a single crystal silicon substrate, a glass substrate, a quartz substrate, a quartz substrate, a polycrystalline substrate, and the like are used as substrates having different etching characteristics depending on the purpose and application of the multilayer substrate to be manufactured. Should be selected. When a glass substrate, a quartz substrate, a quartz substrate, or a polycrystalline substrate is selected, a femtosecond (f second) or picosecond (p second) pulse laser is used as the laser beam.

(3) In the above embodiment, the case where a silicon substrate is used as the substrate and a potassium hydroxide solution is used as the etching solution is described. However, any alkaline solution may be used. Further, when a glass substrate, a quartz substrate, or a quartz substrate is used as the substrate, a hydrofluoric acid (HF) -based solution is used as the etching solution.
(4) The relay substrate (rearrangement wiring substrate for semiconductor devices) shown in FIGS. 4 and 5 has been described as a specific example of the multilayer substrate manufactured by the manufacturing method of the above embodiment. However, in addition to this, it is most suitable for manufacturing an ink jet head (ink flow path) of an ink jet printer, a chemical liquid flow path for analyzing a small amount of chemical liquid, and the like.

  DESCRIPTION OF SYMBOLS 1-3 ... Silicon substrate, 4, 5 ... Etching protective film, 6, 8 ... Vertical hole, 7 ... Horizontal hole, 9 ... Laser beam, 10-12 ... Path | route, 13- 15 ... Altered part

Claims (5)

A method for producing a multilayer substrate comprising a plurality of substrates bonded together,
The plurality of substrates comprises a combination of at least a first substrate and a second substrate having different etching characteristics,
A first step of irradiating a laser beam along a path in which the first hole of the first substrate is formed to alter the inside of the first substrate to form a first altered portion;
A second step of irradiating a laser beam along a path in which the second hole of the second substrate is formed to alter the inside of the second substrate to form a second altered portion;
A third step of etching the first altered portion and the second altered portion, respectively, to form the first hole and the second hole, respectively;
A method for producing a multilayer substrate, comprising:   The plurality of substrates comprises a combination of at least a first substrate and a second substrate having different etching characteristics according to the direction or shape of each hole obtained by etching each substrate. 2. A method for producing a multilayer substrate according to 1.   The multilayer substrate according to claim 1 or 2, wherein the bonding of the plurality of substrates is performed prior to the first step, or is performed between the second step and the third step. Manufacturing method.   The combination of the plurality of substrates is a combination of at least two of a single crystal silicon substrate, a glass substrate, a quartz substrate, a quartz substrate, and a polycrystalline substrate. 2. A method for producing a multilayer substrate according to claim 1.   The combination of the plurality of substrates is two single crystal silicon substrates having different etching characteristics, one is a silicon substrate having a plane orientation (110) and the other is a silicon substrate having a plane orientation (100). The method for manufacturing a multilayer substrate according to any one of claims 1 to 3.

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