JP2023177917A - Semiconductor device and manufacturing method for the same - Google Patents

Abstract

To provide a manufacturing method for a semiconductor device in which substrates with metal electrodes can be bonded together at low temperature and low pressure.SOLUTION: A manufacturing method for a semiconductor device includes the steps of: preparing a first substrate including a plurality of first metal electrodes and a first insulating part disposed surrounding the first metal electrodes, and a second substrate including a plurality of second metal electrodes and a second insulating part disposed surrounding the second metal electrodes; applying conductive ink by an ink-jetting method on the first metal electrodes and/or the second metal electrodes; overlapping the first substrate and the second substrate so that the first metal electrodes and the second metal electrodes face each other through the conductive ink or a solidified substance thereof; and calcining the conductive ink or the solidified substance thereof by heating.SELECTED DRAWING: None

Description

The present invention relates to a semiconductor device and a method for manufacturing the same.

In recent years, there has been a demand for higher speed, lower power consumption, larger capacity, lower cost, etc. of electronic devices, and there has been a demand for smaller and more multilayered circuit boards, higher density mounting of device chips, etc. In particular, for the purpose of improving the performance of semiconductor devices, there is a demand for mounting different types of device chips on a circuit board at narrow intervals (high density).

Conventionally, device chips have been mounted on circuit boards by soldering or the like. However, when device chips are mounted at a high density, the solder joints of adjacent device chips come into contact with each other, resulting in a short circuit. Additionally, since solder generally has low thermal conductivity, heat tends to accumulate in solder joints, which can sometimes cause devices to malfunction. Furthermore, alloying between the solder and the electrode may occur, resulting in cracking of the solder joint.

Therefore, in recent years, a technique of directly overlapping metal electrodes of two substrates (eg, a circuit board and a device chip) and bonding the metal electrodes together by metal diffusion bonding or the like has been studied (eg, Patent Document 1, etc.). With this technology, heat generation, cracking, etc. are unlikely to occur at the joint. Further, it is difficult for adjacent electrodes to come into contact with each other.

JP 2017-63203 Publication

A method (prior art) of diffusion bonding metal electrodes together as in Patent Document 1 will be described with reference to FIGS. 1A to 1C. In this method, first, as shown in FIG. 1A, two substrates 110 and 120 are prepared, each having metal electrodes 111 and 121 and insulating parts 112 and 122 disposed around the metal electrodes. The insulating parts 112 and 122 are members for protecting the metal electrodes 111 and 121 and increasing the bonding strength at the bonding surfaces of the two substrates 110 and 120.

Then, in order to smooth the surfaces of the metal electrodes 111 and 121 and the insulating parts 112 and 112 on these substrates 110 and 120, a planarization process such as chemical mechanical polishing (CMP) is performed. I do. At this time, as shown in FIGS. 1A and 1B, it is necessary to adjust so that the difference between the heights of the metal electrodes 111 and 121 and the heights of the insulating parts 112 and 122 is 100 nm or less. However, in general, the coefficient of thermal expansion of the metal electrodes 111 and 121 is larger than that of the insulating parts 112 and 122. Therefore, if the height of the metal electrodes 111, 121 and the height of the insulating parts 112, 122 are made the same, thermal expansion of the metal electrodes 111, 121 during metal electrode bonding will cause a gap between the two insulating parts 112, 122. A gap will occur. On the other hand, if the height of the metal electrodes 111, 121 is too low compared to the height of the insulating parts 112, 122, they will not come into sufficient contact even when heated, and the two metal electrodes 111, 121 cannot be joined. Therefore, it is necessary to adjust the heights of the metal electrodes 111 and 121 on the order of nanometers.

After the smoothing process, the two substrates 110 and 120 are overlapped and temporarily fixed so that the metal electrodes 111 and 121 face each other (FIG. 1B). Then, by heating the two substrates 110 and 120 while pressing them together, metal diffusion bonding is caused between the two metal electrodes 111 and 121. Through these steps, a semiconductor device in which the metal electrodes of the two substrates 110 and 120 are integrated is obtained (FIG. 1C).

However, with the above method, it is very difficult to adjust the thickness of the metal electrodes 111 and 121 on the order of nanometers by smoothing treatment, especially when the substrate becomes large or the number of device chips to be connected increases. , there was a problem that thickness adjustment became even more difficult.

Furthermore, in order to cause diffusion bonding between the two metal electrodes 111 and 121, it is necessary to raise the temperature to about 400° C. or to press the substrates 110 and 120 together with high pressure. Therefore, there is a problem in that the substrate (for example, a circuit board or a device) may deteriorate or be damaged due to heat or pressure.

The present invention aims to provide a method for manufacturing a semiconductor device that allows substrates having metal electrodes to be bonded together at low temperature and pressure, and to provide a semiconductor device obtained from the method.

The present invention provides a first substrate having a plurality of first metal electrodes and a first insulating part arranged so as to surround each of the first metal electrodes, a plurality of second metal electrodes, and each of the second metal electrodes. a step of preparing a second substrate having a second insulating portion arranged so as to surround the second insulating portion; and a step of applying conductive ink on the first metal electrode and/or the second metal electrode by an inkjet method; The first substrate and the second substrate are stacked so that the first metal electrode and the second metal electrode face each other with the conductive ink or solidified material thereof interposed therebetween, and the conductive ink or the solidified material thereof is heated. A method for manufacturing a semiconductor device is provided, which includes a step of firing the solidified product.

According to the method for manufacturing a semiconductor device of the present invention, substrates having metal electrodes can be bonded together at low temperature and pressure. Further, according to the method, bonding defects between metal electrodes are less likely to occur, and a high-quality semiconductor device can be obtained.

1A to 1C are schematic cross-sectional views showing steps of a conventional method for manufacturing a semiconductor device. 2A to 2C are schematic cross-sectional views showing steps of a method for manufacturing a semiconductor device according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing another example of a substrate used in the method for manufacturing a semiconductor device according to an embodiment of the present invention.

Hereinafter, the semiconductor manufacturing method and semiconductor device of the present invention will be described using specific embodiments as examples. However, the method for manufacturing a semiconductor device and the semiconductor device of the present invention are not limited to the embodiment.

1. Method for Manufacturing a Semiconductor Device A method for manufacturing a semiconductor device according to the present invention will be described with reference to FIGS. 2A to 2C. In the method for manufacturing a semiconductor device of the present invention, as shown in FIG. 2A, a first substrate 10 having a plurality of first metal electrodes 11 and a first insulating part 12 arranged so as to surround the first metal electrodes 11 , a plurality of second metal electrodes 21, and a second substrate 10 having a second insulating section 22 arranged so as to surround the second metal electrodes 21 is prepared (hereinafter also referred to as a "preparation step"). Subsequently, as shown in FIG. 2B, an inkjet method is applied onto one or both of the first metal electrode 11 and the second metal electrode 21 (in the embodiment shown in FIG. 2B, only on the first metal electrode 11). Conductive ink 90 is applied (hereinafter also referred to as "conductive ink application step"). Thereafter, as shown in FIG. 2C, the first substrate 10 and the second substrate 20 are arranged so that the first metal electrode 11 and the second metal electrode 21 face each other with the conductive ink 90 (or a solidified product thereof) in between. Layering (hereinafter also referred to as "lamination process"). Then, the conductive ink 90 (or its solidified product) is fired by heating (hereinafter also referred to as a "baking process").

As mentioned above, in the conventional metal diffusion bonding method, it is necessary to strictly control the height of the metal electrode on the order of nanometers. Furthermore, in order to diffusion bond metal electrodes together, it was necessary to raise the temperature of the substrate and apply high pressure to the substrate. On the other hand, in the method for manufacturing a semiconductor device of the present invention, a conductive ink 90 is applied between the first metal electrode 11 and the second metal electrode 21 by an inkjet method, and the conductive ink 90 (or its solidified product) is coated by an inkjet method. ) to join the first metal electrode 11 and the second metal electrode 21. Therefore, the heights of the first metal electrode 11 and the second metal electrode 21 (hereinafter also collectively referred to as "metal electrodes 11 and 21") are the same as those of the first substrate 10 and the second substrate 20 (hereinafter collectively referred to as "metal electrodes 11 and 21"). Even if there is variation within the substrates (also referred to as "substrates 10, 20"), it can be adjusted by adjusting the amount of applied conductive ink 90, and the first metal electrode 11 and the second metal electrode 21 can be reliably bonded. In other words, there is a great advantage that the heights of the metal electrodes 11 and 21 do not have to be strictly controlled.

Furthermore, when the first metal electrode 11 and the second metal electrode 21 are bonded by firing the conductive ink 90 (or its solidified product), it is not necessary to press the substrates 10 and 20 together with high pressure. Furthermore, the temperature during firing can also be set to a relatively low temperature. Therefore, it is very useful for bonding various types of devices. Furthermore, when laminating a plurality of substrates using the conventional method, it was necessary to bond metal electrodes each time one substrate was laminated. On the other hand, according to the method for manufacturing a semiconductor device of the present invention, it is also possible to laminate a plurality of substrates with conductive ink interposed therebetween, and then to bake the conductive ink all at once. Therefore, there is an advantage that the time required to manufacture a semiconductor device is extremely short.

Each step of the method for manufacturing a semiconductor device of the present invention will be described in detail below.

(preparation process)
In the preparation step, a first substrate 10 having a plurality of first electrodes 11 and a first insulating part 12 arranged to surround the first substrate 10, a plurality of second metal electrodes 21, and a first substrate 10 surrounding each second metal electrode 21 are prepared. A second substrate 10 having a second insulating portion 22 arranged as shown in FIG.

Here, the structure of each substrate 10, 20 is not particularly limited, but each substrate 10, 20 usually has one surface of the substrate body 13, 23 (first substrate body 13, second substrate body 23), or both surfaces. It has a structure in which metal electrodes 11 and 21 and insulating parts 12 and 22 are arranged on each surface. Further, the size (area) of the two substrates 10 and 20 is not particularly limited, and the two substrates 10 and 20 may have the same size, for example, as shown in FIG. 2A. On the other hand, the first substrate 10 and the second substrate 20 may have different sizes, such as when the first substrate 10 is an interposer substrate and the second substrate 20 is a variety of device chips. Further, as shown in FIG. 3, one of the substrates (here, the second substrate 20) may be composed of a plurality of device chips.

Furthermore, the structures of the substrate bodies 13 and 23 are appropriately selected depending on the type of the substrates 10 and 20. For example, it may be a substantially rectangular parallelepiped structure or a structure having arbitrary convex portions or concave portions. Furthermore, as shown in FIG. 3, a through hole (not shown) or the like may be provided to connect one surface of the substrate body 13 to the other surface.

The constituent materials of the two substrate bodies 13 and 23 are appropriately selected depending on their respective uses, and may be the same or different. Examples of the constituent materials of the substrate bodies 13 and 23 include semiconductors such as Si, InP, GaN, GaAs, InGaAs, InGaAlAs, and SiC; borosilicate glass (Pyrex (registered trademark)), quartz glass (SiO ₂ ), sapphire; Oxides, carbides, or nitrides such as ZrO ₂ , Si ₃ N ₄ , AlN; piezoelectrics or dielectrics such as BaTiO ₃ , LiNbO ₃ , SrTiO ₃ , diamond; Al, Ti, Fe, Cu, Ag, Au, Metals such as Pt, Pd, Ta, and Nb are included. Further, the constituent material of the substrate bodies 13 and 23 may be resin, examples of which include polydimethylsiloxane (PDMS), epoxy resin, phenol resin, polyimide, benzocyclobutene resin, polybenzoxazole, etc. . Moreover, the substrate bodies 13 and 23 may be configured with a single layer or with multiple layers. For example, on the surface of the semiconductor described above, an inorganic layer such as silicon oxide, silicon nitride, SiCN (silicon carbonitride); an organic layer containing polyimide resin, polybenzoxazole resin, epoxy resin, cyclotene, etc.; or a layer of organic and inorganic materials. A layer consisting of a composite layer or the like may be formed.

On the other hand, the first metal electrode 11 and the second electrode 21 only need to be arranged at opposing positions when the first substrate 10 and the second substrate 20 are opposed to each other. As shown in FIG. 2A, they may be arranged only on one surface of the substrate bodies 13, 23, or may be arranged on both sides of the substrate bodies 13, 23. Furthermore, as in the first substrate 10 of FIG. 3, the metal electrodes 11 on both sides of the substrate body 13 may be connected to each other via through holes.

Further, the area of the individual metal electrodes 11 and 21 exposed on the surfaces of the substrates 10 and 20 is not particularly limited, but it is preferable that the diameter when viewed from above is about submicron to several hundred microns. ~80 μm is more preferred. When the diameters of the metal electrodes 11 and 21 are within the above range, it becomes easier to apply the conductive ink 90 to the area by an inkjet method in the conductive ink application step described below. Furthermore, the baked product of the conductive ink 90 facilitates reliable connection.

Here, the constituent material of the two metal electrodes 11 and 21 may be any material as long as it has sufficient conductivity. The constituent materials of the two metal electrodes 11 and 21 may be the same or different. Examples of the constituent materials of the metal electrodes 11 and 21 include copper, tin, gold, silver, aluminum, nickel, and the like. The metal electrodes 11 and 21 may contain only one kind of these, or may contain two or more kinds. Among these, copper is particularly preferred from the viewpoint of conductivity and ease of forming the metal electrodes 11 and 21.

The insulating parts 12 and 22 may be disposed at opposing positions and surrounding the metal electrodes 11 and 21 when the first substrate 10 and the second substrate 20 are opposed to each other. The insulating parts 12 and 22 may be arranged in all regions on the substrate bodies 13 and 23 except for the regions where the metal electrodes 11 and 21 are arranged. On the other hand, the insulating parts 12 and 22 may be arranged in a pattern so that parts of the substrate bodies 13 and 23 are exposed.

Moreover, the constituent material of the insulating parts 12 and 22 is not particularly limited as long as it has insulating properties. The constituent materials of the two insulating parts 12 and 22 may be the same or different. Examples of the constituent materials of the insulating parts 12 and 22 include inorganic materials such as _SiO2 , insulating resins, and the like. Further, the insulating parts 12 and 22 may be composed of only one layer, or may be composed of two or more layers.

In the present invention, it is particularly preferable that one or both of the first insulating part 12 and the second insulating part 22 contain a cured resin having a composite modulus of elasticity of 10 GPa or less at 23°C. It is preferable that the substrates 10 and 20 used in the present invention are also subjected to a planarization process (for example, chemical mechanical polishing) after manufacturing, but when the planarization process is performed, the insulating parts 12 and 22 may be scratched, etc. may occur. Then, when the insulating parts 12 and 22 with scratches on their surfaces are overlapped, a gap is created between them. If heating (for example, a firing process described below) is performed in this state, air expands at the interface between the two insulating parts 12 and 22, which may affect the bonding of the two substrates 10 and 20. On the other hand, if at least one of the insulating parts 12, 22 contains a cured resin having the above-mentioned composite modulus, the insulating parts 12, 22 will deform appropriately when the insulating parts 12, 22 are opposed to each other. It is possible to fill in the scratches. Therefore, bonding of the two substrates 10 and 20 is less likely to be hindered, and a high quality semiconductor device can be easily obtained. Furthermore, if the insulating parts 12 and 22 contain a cured resin, when the conductive ink 90 is applied in the conductive ink process described later, the conductive ink 90 will wet the insulating parts 12 and 22 due to its water repellency. Another advantage is that it is difficult to spread and the conductive ink 90 can be easily applied only onto the metal electrodes 11 and 21.

Here, the composite modulus of the cured resin material is preferably 8 GPa or less, more preferably 6 GPa or less. On the other hand, the composite modulus of the cured resin material is preferably 0.1 GPa or more, more preferably 1 GPa or more. When the composite modulus of the cured resin material is 0.1 GPa or more, the resin composition (insulating part) becomes difficult to deform excessively. Therefore, for example, it becomes easier to mount a plurality of substrates (a large number of device chips) at high density. The composite elastic modulus was determined by measuring the unloading-displacement curve at 23°C using a nanoindentator at a test depth of 20 nm. This value is calculated from the maximum load and maximum displacement according to the calculation method of CRC Press Co., Ltd.

In this specification, "cured resin" refers to a composition obtained by curing a composition containing a curable resin, in which 70% or more of the curable resin has undergone a curing reaction, that is, a composition with a curing rate of 70% or more. 70% or more. It is also possible to use an uncured resin composition for the insulating parts 12, 22, but if a cured resin is used for the insulating parts 12, 22, the insulating parts 12, 22 may be excessively deformed in the lamination process described later. This may cause the substrates 10, 20 to be misaligned, the resin (insulating parts 12, 22) to be caught between the opposing metal electrodes 11, 21, or the insulating parts 12, 22 to be formed on the outer periphery of the substrates 10, 20. It can prevent it from sticking out. Further, a general cured resin has a hard surface and is difficult to adhere to other substances, but a cured resin having the above-mentioned composite modulus can adhere to other substances. Therefore, if at least one of the first insulating section 12 and the second insulating section 22 contains the cured resin, simply overlapping the first substrate 10 and the second substrate 20 in the lamination process will remove these. It is possible to properly fix the position.

The cured resin is a curable resin in which bonds or structures such as polyimide, polyamide, polyamideimide, parylene, polyarylene ether, tetrahydronaphthalene, octahydroanthracene, etc. are formed by crosslinking; Curable resins in which a nitrogen ring-containing structure such as benzoxazine is formed; curable resins in which a bond or structure such as Si--O is formed by crosslinking; and a cured product of a siloxane-modified compound. Among these, it is preferable to include a cured resin in which a polyimide, polyamide, or polyamideimide structure is formed by crosslinking, and/or a cured resin in which a siloxane bond is formed, and in particular, a cured product of a curable resin in which both structures are formed. It is preferable to include a cured product of a curable resin. That is, it is preferable that the cured resin material contains a siloxane bond, an amide bond, and/or an imide bond. A method for forming a substrate having an insulating portion containing such a cured resin will be described later.

Here, it is preferable that the surfaces of the insulating parts 12 and 22 and the metal electrodes 11 and 21 of the substrates 10 and 20 are respectively planarized by a planarization process (eg, chemical mechanical polishing method). Further, the height of the metal electrodes 11 and 21 on the surfaces of the substrates 10 and 20 may be approximately the same as the height of the insulating parts 12 and 22; , 21 are lower than the heights of the insulating parts 12 and 22, and the difference therebetween is preferably 300 nm or less, more preferably 100 nm or less. If the height of the insulating parts 12, 22 is higher than the height of the metal electrodes 11, 21 on the surfaces of the substrates 10, 20, this difference in level can be used to inject conductive material at desired positions in the conductive ink application process described below. It becomes easier to apply the ink 90. Further, the height difference has the advantage that the conductive ink 90 can be easily held at a desired position. Note that, in the present invention, there is no particular problem even if the heights of the metal electrodes 11 and 21 vary somewhat within the substrates 10 and 20.

(Conductive ink application process)
In the conductive ink application step, conductive ink 90 is applied onto one or both of the first metal electrode 11 and second metal electrode 21 described above by an inkjet method.

Application of the conductive ink 90 can be performed using a general inkjet device. The coating device (inkjet device) for the conductive ink 90 may be a known device having an ink tank, an (inkjet) recording head, a recording head drive mechanism, and the like. Further, the type of recording head is not particularly limited as long as it is an inkjet type, and may be, for example, a piezo type, a valve type, or an electrostatic type. Furthermore, the conditions during coating are not particularly limited, and are appropriately selected depending on the desired layer thickness, pattern, etc.

The conductive ink 90 may be any ink that exhibits sufficient conductivity after firing. In this specification, the conductive ink 90 is an ink whose film has a volume resistivity of 80 microΩ·cm or less after firing. The volume resistivity of the conductive ink 90 after firing is preferably 1.7 to 10 microΩ·cm, more preferably 8 microΩ·cm or less. The volume resistivity of the conductive ink after firing can be measured by the method described in ASTM D 991.

Here, the conductive ink 90 can be a composition containing, for example, a metal component and a solvent. The metal component may be a simple metal, but may also be an inorganic metal compound, an organic metal compound, a complex, or the like. Here, examples of metals contained in the conductive ink 90 include copper, silver, nickel, tin, gold, platinum, cobalt, and the like. Furthermore, examples of inorganic compounds include copper oxide, silver oxide, and the like. Examples of organometallic compounds include octylamine, oxalic acid, and the like. Examples of complexes include alkanolamine-copper formate, etc.

On the other hand, examples of solvents contained in the conductive ink 90 include alcohol, water, etc. Among these, ethylene glycols and isopropyl are preferred because they are easy to print with an inkjet device and are less likely to affect semiconductor devices. Alcohol (IPA) and the like are preferred.

Furthermore, the conductive ink 90 may contain components other than the metal component and the solvent, as long as the objects and effects of the present invention are not impaired. Examples include citric acid, oxalic acid, and the like.

The amounts of metal components, solvents, etc. in the conductive ink 90 are appropriately selected depending on the viscosity of the conductive ink 90. For example, the viscosity of the conductive ink 90 measured by an E-type viscometer at 25° C. and 20 rpm is preferably 2 to 100 mPa·s, more preferably 2 to 50 mPa·s, and even more preferably 2 to 40 mPa·s. When the viscosity of the conductive ink 90 is within this range, it becomes easier to apply by the above-mentioned inkjet method.

Further, the surface tension of the conductive ink 90 is preferably 25 to 45 mN/m, more preferably 27 to 42 mN/m, and even more preferably 30 to 40 mN/m. Surface tension is a value measured by Wilhelmy method at 25°C. When the surface tension of the conductive ink 90 is 45 mN/m or less, the conductive ink 90 can be appropriately leveled when applied by an inkjet method, and the surfaces of the metal electrodes 11 and 21 can be coated evenly. On the other hand, when the surface tension of the conductive ink 90 is 25 mN/m or more, it is difficult to wet and spread excessively when applied by an inkjet method, and it can be applied only onto the metal electrodes 11 and 21.

After applying the conductive ink 90, the lamination step described below may be performed without removing the solvent in the conductive ink, but the solvent in the conductive ink may be dried if necessary. For example, after applying the conductive ink 90, heating may be performed to 60 to 120°C. By heating after applying the conductive ink 90, the conductive ink 90 can be easily fixed on the surfaces of the metal electrodes 11 and 21.

(Lamination process)
In the lamination process, the first substrate 10 and the second substrate 20 described above are stacked so that the first metal electrode 11 and the second metal electrode 21 face each other with the conductive ink 90 or its solidified material interposed therebetween. In the lamination step, if the insulating parts 12 and 22 contain an uncured or semi-cured resin composition, heating may be performed as necessary to fix the first substrate 10 and the second substrate 20. .

(Firing process)
In the firing step, the conductive ink 90 or its solidified product is fired in a state where the first substrate 10 and the second substrate 20 described above are stacked. The temperature during firing is preferably 100°C or more and 400°C or less, more preferably 120°C or more and 300°C or less. By setting the temperature during firing to 120° C. or higher, the metal component in the conductive ink 90 is integrated with the first electrode 11 and the second electrode 21, and the first electrode 11 and the second electrode 21 are electrically connected. can. Furthermore, if the temperature during firing is 200° C. or lower, it will hardly affect the substrates 10 and 20.

The firing time is preferably 5 to 90 minutes, more preferably 5 to 15 minutes. Within this range, the solvent in the conductive ink 90 can be sufficiently removed. Note that when the insulating parts 12 and 22 include the above-mentioned cured resin, the solvent volatilized from the conductive ink 90 may be absorbed by the insulating parts 12 and 22 (cured resin) or be absorbed through the insulating parts 12 and 22. Easily released to the outside. Therefore, it is easy to obtain a high quality semiconductor device.

Note that the thickness of the layer derived from the conductive ink 90 (also referred to as a "connection layer" in this specification) produced after firing is preferably 300 nm or less, more preferably 100 nm or less. When the thickness of the connection layer is within this range, electrical continuity between the first electrode 11 and the second electrode 21 is hardly affected, and a high-quality semiconductor device can be obtained. Note that the connection layer may diffuse and disappear due to heating in the firing process.

(others)
In the method for manufacturing a semiconductor device described above, the case where only the first substrate and the second substrate are bonded has been described, but according to the method described above, it is also possible to bond a plurality of substrates. In this case, three or more substrates may be prepared in the preparation step, a conductive ink application step and a lamination step may be repeated to form a laminate, and finally a firing step may be performed all at once.

(Preferred substrate manufacturing method)
Hereinafter, a method for manufacturing a substrate having an insulating part containing the above-mentioned cured resin and the cured resin will be described. The method for manufacturing the substrate is not particularly limited as long as the metal electrode and the insulating portion can be formed at desired positions on the substrate body. For example, a metal electrode is formed at a desired position on the substrate body, a composition containing a curable resin (hereinafter also referred to as "insulating material") is applied and cured to cover it, and then a chemical The metal electrode may be exposed by mechanical polishing. Alternatively, the metal electrode may be formed after applying an insulating material to a desired position on the substrate body and curing the insulating material to form an insulating part. Further, an insulating material may be applied to the entire surface of the substrate body, cured, and then patterned by etching or the like to form a metal electrode in the exposed area of the substrate body. In either method, it is preferable to perform chemical mechanical polishing to adjust the surface condition, height, etc. of the metal electrode and the insulating part as appropriate.

In either case, the metal electrode can be formed by a known method. Examples of methods for forming metal electrodes include electrolytic plating, electroless plating, sputtering, and inkjet methods.

On the other hand, the insulating part can be manufactured by various methods using the insulating material described below. Hereinafter, a specific insulating material for forming an insulating part containing a cured resin having a composite modulus of elasticity at 23° C. of 10 GPa or less, a method for forming the insulating part, and physical properties of the insulating part will be described.

(1) Insulating material The insulating material for forming the insulating part containing the resin cured product having a composite modulus of elasticity of 10 GPa or less at 23°C as described above includes the curable resin (A), the crosslinking agent (B), and the necessary It is preferable that the composition contains an additive (C) and a polar solvent (D) depending on the conditions. Each will be explained below.

・Curing resin (A)
The curable resin (A) is a curable resin in which bonds or structures such as polyimide, polyamide, polyamideimide, parylene, polyarylene ether, tetrahydronaphthalene, octahydroanthracene, etc. are formed by crosslinking; polybenzoxazal is formed by curing. , a curable resin in which a nitrogen ring-containing structure such as polybenzoxazine is formed; a curable resin in which a bond or structure such as Si-O is formed by crosslinking; a siloxane-modified compound; It is preferable that there be.

Among these, curable resins in which a polyimide, polyamide, or polyamide-imide structure is formed by crosslinking, and/or curable resins in which siloxane bonds are formed are preferred. Hereinafter, such a curable resin will be explained as an example, but the curable resin is not limited to these.

Preferred curable resins (A) include curable resins that have a cationic functional group containing at least one of a primary nitrogen atom and a secondary nitrogen atom, and have a weight average molecular weight of 90 to 400,000. . The cationic functional group is not particularly limited as long as it can be positively charged and contains at least one of a primary nitrogen atom and a secondary nitrogen atom. The curable resin (A) may contain a tertiary nitrogen atom in addition to the primary nitrogen atom and the secondary nitrogen atom. Furthermore, in addition to cationic functional groups, it further contains anionic functional groups such as carboxylic acid groups, sulfonic acid groups, and sulfuric acid groups, and nonionic functional groups such as hydroxyl groups, carbonyl groups, and ether groups (-O-). It's okay to stay.

As used herein, the term "primary nitrogen atom" refers to a nitrogen atom to which one atom other than a hydrogen atom is bonded, examples of which include the nitrogen atom of a primary amino group, etc. . Also. "Secondary nitrogen atom" refers to a nitrogen atom to which two atoms other than hydrogen atoms are bonded. "Tertiary nitrogen atom" refers to a nitrogen atom to which three atoms other than hydrogen atoms are bonded.

When the curable resin (A) contains primary nitrogen atoms, the proportion of primary nitrogen atoms in the total nitrogen atoms in the curable resin (A) is preferably 20 mol% or more, and 25% by mole or more. It is more preferably mol% or more, and even more preferably 30 mol% or more.

In addition, when the curable resin (A) contains secondary nitrogen atoms, the proportion of secondary nitrogen atoms in the total nitrogen atoms in the curable resin (A) is 5 mol% or more and 50 mol% or less. The content is preferably 10 mol% or more and 45 mol% or less.

When the curable resin (A) contains tertiary nitrogen atoms, the proportion of tertiary nitrogen atoms in the total nitrogen atoms in the curable resin (A) is 20 mol% or more and 50 mol% or less. is preferable, and more preferably 25 mol% or more and 45 mol% or less.

Here, examples of the above-mentioned curable resin (A) include an aliphatic amine compound or its derivative (a1), an amine compound having a ring structure (a2), a compound having a siloxane bond and an amino group (a3), etc. It will be done. Among these, a compound (a3) having a siloxane bond and an amino group is particularly preferred as the curable resin (A).

Specific examples of the aliphatic amine compound or its derivative (a1) include ethyleneimine, propyleneimine, butyleneimine, pentyleneimine, hexyleneimine, heptyleneimine, octyleneimine, trimethyleneimine, tetramethyleneimine, pentamethyleneimine, and hexyleneimine. Included are polyalkylene imine, which is a polymer of alkylene imine such as methylene imine and octamethylene imine, or a derivative thereof; polyallylamine; and polyacrylamide.

Examples of the above polyalkylene imine derivatives include derivatives such as polyethylene imine in which an alkyl group (preferably an alkyl group having 1 to 10 carbon atoms) or an aryl group is introduced into polyalkylene imine; derivatives into which a functional group has been introduced; highly branched derivatives obtained by reacting a polyalkylene imine with a cationic functional group-containing monomer (for example, an aminoethyl group) to improve the degree of branching of the polyalkylene imine.

When the curable resin (A) is an aliphatic amine compound or its derivative (a1), its weight average molecular weight is preferably 10,000 to 200,000. The weight average molecular weight is a polyethylene glycol equivalent value measured by gel permeation chromatography (GPC). Specifically, an aqueous solution with a sodium nitrate concentration of 0.1 mol/L was used as a developing solvent, and an analyzer Shodex DET RI-101 and two types of analytical columns (Tosoh TSKgel G6000PWXL-CP and TSKgel G3000PWXL-CP) were used. The refractive index is detected at a flow rate of 1.0 mL/min, and the value is calculated using analysis software (Empower 3 manufactured by Waters) using polyethylene glycol/polyethylene oxide as a standard product.

On the other hand, the amine compound (a2) having a ring structure is preferably an amine compound having a ring structure and a weight average molecular weight of 90 or more and 600 or less, without having a Si--O bond in the molecule. Examples of the amine compound (a2) having a ring structure include alicyclic amine compounds, aromatic amine compounds, heterocyclic amine compounds, etc. Among them, aromatic amines are preferred from the viewpoint of being more stable. Compounds are preferred. The amine compound (a2) may have multiple ring structures within the molecule. At this time, the plurality of ring structures may be the same or different. In particular, the amine compound (a2) has a primary amino group, from the viewpoint that it forms an amide, amide-imide, or imide structure with the crosslinking agent (B) described below, and tends to improve the heat resistance of the resin. is preferable, and diamine compounds and triamine compounds having two or more primary amino groups are more preferable.

Examples of the alicyclic amine compound corresponding to the amine compound (a2) having a ring structure include cyclohexylamine, dimethylaminocyclohexane, and the like.

Examples of the aromatic amine compound corresponding to the amine compound (a2) having the above ring structure include diaminodiphenyl ether, xylene diamine (preferably para-xylene diamine), diaminobenzene, diaminotoluene, methylene dianiline, dimethyldiaminobiphenyl, bis (trifluoromethyl)diaminobiphenyl, diaminobenzophenone, diaminobenzanilide, bis(aminophenyl)fluorene, bis(aminophenoxy)benzene, bis(aminophenoxy)biphenyl, dicarboxydiaminodiphenylmethane, diaminoresorcin, dihydroxybenzidine, diaminobenzidine, Included are 1,3,5-triaminophenoxybenzene, 2,2'-dimethylbenzidine, tris(4-aminophenyl)amine, 2,7-diaminofluorene, 1,9-diaminofluorene, dibenzylamine, and the like.

Examples of the heterocyclic amine corresponding to the amine compound (a2) having a ring structure include melamine, ammeline, melam, melem, tris(4-aminophenyl)amine, and the like. Further, the amine compound (a2) may be an amine compound having both a heterocycle and an aromatic ring, and examples thereof include N2,N4,N6-tris(4-aminophenyl)-1,3, Includes 5-triazine-2,4,6-triamine and the like.

When the curable resin (A) is an amine compound (a2) having a ring structure, the molecular weight of the compound is preferably 90 or more and 600 or less.

On the other hand, examples of the compound (a3) having a siloxane bond and an amino group include siloxane diamine, and a silane coupling agent having a siloxane bond and an amino group or a polymer thereof.

上記化学式において、Ｍｅはメチル基を表し、ｉは０～４の整数を表し、ｊは１～３の整数を表す。当該化学式で表される化合物の具体例には、１，３－ビス（３－アミノプロピル）テトラメチルジシロキサン（上記化学式においてｉ＝０、ｊ＝１）、１，３－ビス（２－アミノエチルアミノ）プロピルテトラメチルジシロキサン（上記化学式において、ｉ＝１、ｊ＝１）が含まれる。 Examples of the siloxane diamine include compounds represented by the following chemical formula.

In the above chemical formula, Me represents a methyl group, i represents an integer of 0 to 4, and j represents an integer of 1 to 3. Specific examples of the compound represented by the chemical formula include 1,3-bis(3-aminopropyl)tetramethyldisiloxane (i=0, j=1 in the above chemical formula), 1,3-bis(2-amino ethylamino)propyltetramethyldisiloxane (in the above chemical formula, i=1, j=1).

上記化学式において、Ｒ^１は置換されていてもよい炭素数１～４のアルキル基を表す。Ｒ^２及びＲ^３は、それぞれ独立に、置換（骨格にカルボニル基、エーテル基等を含んでもよい）されていてもよい炭素数１～１２のアルキレン基、エーテル基又はカルボニル基を表す。Ｒ^４及びＲ^５は、それぞれ独立に、置換されていてもよい炭素数１～４のアルキレン基又は単結合を表す。Ａｒは２価又は３価の芳香環を表す。Ｘ^１は水素又は置換されていてもよい炭素数１～５のアルキル基を表す。Ｘ^２は水素、シクロアルキル基、ヘテロ環基、アリール基又は置換（骨格にカルボニル基、エーテル基等を含んでもよい）されていてもよい炭素数１～５のアルキル基、を表す。複数のＲ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｘ^１は同じであっても異なっていてもよい。Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｘ^１、Ｘ^２におけるアルキル基及びアルキレン基の置換基としては、それぞれ独立に、アミノ基、ヒドロキシ基、アルコキシ基、シアノ基、カルボン酸基、スルホン酸基、ハロゲン等が挙げられる。ｐ１は０～２の整数を表し、ｑ１は１～３の整数を表す。このとき、ｐ１＋ｑ１＝３である。またｎ１は１～３の整数を表し、ｒ１、ｓ１、ｔ１、ｕ１、ｖ１、およびｗ１はそれぞれ０または１を表す。 On the other hand, examples of silane coupling agents having a siloxane bond and an amino group include compounds represented by the following chemical formula.

In the above chemical formula, R ¹ represents an optionally substituted alkyl group having 1 to 4 carbon atoms. R ² and R ³ each independently represent an alkylene group having 1 to 12 carbon atoms, an ether group, or a carbonyl group, which may be substituted (the skeleton may contain a carbonyl group, ether group, etc.). R ⁴ and R ⁵ each independently represent an optionally substituted alkylene group having 1 to 4 carbon atoms or a single bond. Ar represents a divalent or trivalent aromatic ring. X ¹ represents hydrogen or an optionally substituted alkyl group having 1 to 5 carbon atoms. X ² represents hydrogen, a cycloalkyl group, a heterocyclic group, an aryl group, or an optionally substituted alkyl group having 1 to 5 carbon atoms (the skeleton may include a carbonyl group, an ether group, etc.). A plurality of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and X ¹ may be the same or different. Substituents for the alkyl group and alkylene group in R ¹ , R ² , R ³ , R ⁴ , R ⁵ , X ¹ , and X ² each independently include an amino group, a hydroxy group, an alkoxy group, a cyano group, and a carboxylic acid group. group, sulfonic acid group, halogen, etc. p1 represents an integer from 0 to 2, and q1 represents an integer from 1 to 3. At this time, p1+q1=3. Further, n1 represents an integer from 1 to 3, and r1, s1, t1, u1, v1, and w1 each represent 0 or 1.

Specific examples of the silane coupling agent having a siloxane bond and an amino group represented by the above formula include N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl) -3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminoisobutyldimethylmethoxysilane, N-(2-aminoethyl)-3-aminoisobutylmethyldimethoxysilane, N-(2-aminoethyl) )-11-aminoundecyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, (aminoethylaminoethyl)phenyltriethoxysilane, Methylbenzylaminoethylaminopropyltrimethoxysilane, benzylaminoethylaminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, (aminoethylaminoethyl)phenethyltrimethoxysilane, (aminoethylaminomethyl)phenethyltrimethoxysilane, N -[2-[3-(trimethoxysilyl)propylamino]ethyl]ethylenediamine, 3-aminopropyldiethoxymethylsilane, 3-aminopropyldimethoxymethylsilane, 3-aminopropyldimethylethoxysilane, 3-aminopropyldimethylmethoxy Silane, trimethoxy[2-(2-aminoethyl)-3-aminopropyl]silane, diaminomethylmethyldiethoxysilane, methylaminomethylmethyldiethoxysilane, p-aminophenyltrimethoxysilane, N-methylaminopropyltriethoxy Silane, N-methylaminopropylmethyldiethoxysilane, (phenylaminomethyl)methyldiethoxysilane, acetamidopropyltrimethoxysilane, and hydrolysates thereof.

In addition, examples of silane coupling agents having a siloxane bond and an amino group other than those mentioned above include N,N-bis[3-(trimethoxysilyl)propyl]ethylenediamine, N,N'-bis[3-(trimethoxysilyl) silyl)propyl]ethylenediamine, bis[(3-triethoxysilyl)propyl]amine, piperazinylpropylmethyldimethoxysilane, bis[3-(triethoxysilyl)propyl]urea, bis(methyldiethoxysilylpropyl)amine, 2,2-dimethoxy-1,6-diaza-2-silacyclooctane, 3,5-diamino-N-(4-(methoxydimethylsilyl)phenyl)benzamide, 3,5-diamino-N-(4-( These include triethoxysilyl)phenyl)benzamide, 5-(ethoxydimethylsilyl)benzene-1,3-diamine, and hydrolysates thereof.

In addition, as the curable resin (A), the silane coupling agent having a siloxane bond and an amino group may be combined with a silane coupling agent having a mercapto group, which does not have an amino group, or the like.

Further, the compound (a3) having a siloxane bond and an amino group may be a polymer of the silane coupling agent. By hydrolytically polymerizing the above-mentioned silane coupling agents, a polymer in which the silane coupling agents are polymerized through siloxane bonds (Si--O--Si) can be obtained. The structure of the polymer is not particularly limited, and the polymer may have any structure such as a linear siloxane structure, a branched siloxane structure, a cyclic siloxane structure, or a cage-like siloxane structure.

When the curable resin (A) is a compound (a3) having a siloxane bond and an amino group, the total number of primary nitrogen atoms and secondary nitrogen atoms relative to the number of silicon atoms in the compound (a3). The ratio (total number of primary nitrogen atoms and secondary nitrogen atoms/number of silicon atoms) is preferably 0.2 or more and 5 or less. When the ratio is within this range, a smooth insulating portion can be easily obtained.

In addition, when the above-mentioned curable resin (A) is a compound (a3) having a siloxane bond and an amino group, silicon atoms in the compound (a3) are The ratio of the number of moles of a non-crosslinking group (for example, a methyl group) bonded to a silicon atom to the number of moles of a non-crosslinking group (number of moles of non-crosslinking group/number of moles of silicon atom) is preferably less than 2. This increases the crosslinking density in the insulating part and further increases the adhesion between the substrate body and the opposing insulating part.

Furthermore, when the curable resin (A) is a compound (a3) having a siloxane bond and an amino group, its weight average molecular weight is preferably 130 or more and 10,000 or less, more preferably 130 or more and 5,000 or less, and even more preferably 130 or more and 2,000 or less. preferable. The weight average molecular weight is a polyethylene glycol equivalent value measured by gel permeation chromatography (GPC) according to the method described above.

Here, from the viewpoint of easily obtaining a smooth insulation part, the curable resin (A) is preferably an aliphatic amine compound (a1) or a compound having a siloxane bond and an amino group (a3), and has a heat resistant From this viewpoint, the compound (a3) having a siloxane bond and an amino group is more preferable.

The amount of curable resin (A) in the solid content of the insulating material is not particularly limited, but is preferably 1% by mass or more and 82% by mass or less, more preferably 5% by mass or more and 82% by mass or less, and 13% by mass or more and 82% by mass. % or less is more preferable.

・Crosslinking agent (B)
The crosslinking agent (B) for crosslinking the curable resin (A) has a -C(=O)OX group (hereinafter also referred to as a "COOX group") in the molecule. The weight average molecular weight is is preferably 200 or more and 600 or less.

The number of COOX groups in the crosslinking agent (B) may be 3 or more, preferably 3 or more and 6 or less, and more preferably 3 or 4. Further, X in the COOX group may be a hydrogen atom or an alkyl group having 1 or more and 6 or less carbon atoms, and is preferably a hydrogen atom, a methyl group, an ethyl group, or a propyl group. Note that X in the plurality of COOX groups may be the same or different.

The number of COOH groups in the crosslinking agent (B) may be 6 or less, preferably 1 or more and 4 or less, more preferably 2 or more and 4 or less, and even more preferably 2 or 3.

The weight average molecular weight of the crosslinking agent (B) may be 200 or more and 600 or less, and more preferably 200 or more and 400 or less.

It is preferable that the crosslinking agent (B) has a ring structure within the molecule. The ring structure may be either an alicyclic structure or an aromatic ring structure. Further, the crosslinking agent (B) may have a plurality of ring structures within the molecule, and in this case, the plurality of ring structures may be the same or different.

The number of carbon atoms constituting the alicyclic structure is preferably 3 or more and 8 or less, more preferably 4 or more and 6 or less. Further, the alicyclic structure may be saturated or unsaturated. Examples of alicyclic structures include saturated alicyclic structures such as cyclopropane ring, cyclobutane ring, cyclopentane ring, cyclohexane ring, cycloheptane ring, and cyclooctane ring; cyclopropene ring, cyclobutene ring, cyclopentene ring, cyclohexene ring, and cycloheptene ring. It includes unsaturated alicyclic structures such as rings and cyclooctene rings.

Examples of aromatic ring structures include benzene aromatic rings such as benzene ring, naphthalene ring, anthracene ring, and perylene ring; aromatic heterocycles such as pyridine ring and thiophene ring; non-benzene aromatic rings such as indene ring and azulene ring. is included.

The ring structure that the crosslinking agent (B) has in its molecule is preferably at least one selected from the group consisting of a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a benzene ring, and a naphthalene ring. A benzene ring and a naphthalene ring are preferred from the viewpoint of improving adhesiveness with the main body and the opposing insulating part. Note that examples of structures containing a benzene ring include a biphenyl structure, a benzophenone structure, a diphenyl ether structure, and the like.

Moreover, it is also preferable that the crosslinking agent (B) has a fluorine atom in the molecule. The number of fluorine atoms in the crosslinking agent (B) is preferably 1 or more and 6 or less, more preferably 3 or more and 6 or less. The crosslinking agent (B) may have an alkyl group such as a trifluoroalkyl group or a hexafluoroisopropyl group.

Here, the crosslinking agent (B) may be a carboxylic acid compound in which all of the plurality of COOX groups described above are COOH groups, and X of at least one COOX group among the plurality of COOX groups described above is It may be any carboxylic acid ester compound that is an alkyl group having 1 to 6 carbon atoms (that is, a group containing an ester group). When the crosslinking agent (B) is a carboxylic acid compound, the number of COOH groups is preferably 4 or less, more preferably 3 or 4. When the crosslinking agent (B) is a carboxylic acid ester compound, the number of COOH groups and the number of ester groups are both preferably 3 or less, and the numbers of COOH groups and ester groups are both more preferably 2 or less.

Specific examples of the carboxylic acid compounds include 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, 1,3,5-cyclohexanetricarboxylic acid, 1,2 , 4-cyclohexanetricarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 1,2,3,4,5,6-cyclohexanehexacarboxylic acid and other alicyclic carboxylic acids; 1,2,4-benzene Benzenecarboxylic acids such as tricarboxylic acid, 1,3,5-benzenetricarboxylic acid, pyromellitic acid, benzenepentacarboxylic acid, mellitic acid; 1,4,5,8-naphthalenetetracarboxylic acid, 2,3,6,7 -Naphthalenecarboxylic acid such as naphthalenetetracarboxylic acid; 3,3',5,5'-tetracarboxydiphenylmethane, biphenyl-3,3',5,5'-tetracarboxylic acid, biphenyl-3,4',5- Tricarboxylic acid, biphenyl-3,3',4,4'-tetracarboxylic acid, benzophenone-3,3',4,4'-tetracarboxylic acid, 4,4'-oxydiphthalic acid, 3,4'-oxydiphthalic acid , 1,3-bis(phthalic acid)tetramethyldisiloxane, 4,4'-(Ethyne-1,2-diyl)diphthalic acid, 4,4'-(1,4-phenylenebis(oxy))diphthalic acid, 4,4'-([1,1'- 4,4'-([1,1'-biphenyl]-4,4'-diylbis(oxy))diphthalic acid ((oxybis(4,1-phenylene))bis(oxy))diphthalic acid (4,4'-((oxybis(4,1-phenylene))bis(oxy))diphthalic acid; perylene- perylenecarboxylic acids such as 3,4,9,10-tetracarboxylic acid; anthracenecarboxylic acids such as anthracene-2,3,6,7-tetracarboxylic acid; 4,4'-(hexafluoroisopropylidene) diphthalic acid; Included are fluorinated aromatic ring carboxylic acids such as 9,9-bis(trifluoromethyl)-9H-xanthene-2,3,6,7-tetracarboxylic acid and 1,4-ditrifluoromethylpyromellitic acid.

On the other hand, when the crosslinking agent (B) is a carboxylic acid ester compound, the alkyl group constituting the ester bond, that is, X in the COOX group is preferably a methyl group, ethyl group, propyl group, or butyl group, and when forming the insulating part An ethyl group or a propyl group is more preferable from the viewpoint of further suppressing aggregation due to association between the curable resin (A) and the crosslinking agent (B).

一般式（Ｂ－１）～（Ｂ－６）におけるＲは、それぞれ独立に炭素数１以上６以下のアルキル基であり、メチル基、エチル基、プロピル基、またはブチル基が好ましく、エチル基またはプロピル基がより好ましい。また、一般式（Ｂ－２）におけるＹはＯ、Ｃ＝Ｏ、またはＣ（ＣＦ_３）_２からなる群から選ばれる基を表す。当該ハーフエステルは、上述のカルボン酸化合物の無水物（カルボン酸無水物）を、アルコール溶媒に混合し、カルボン酸無水物を開環させて生成することが可能である。 Specific examples of carboxylic acid ester compounds include compounds in which the hydrogen group of at least one carboxy group of the carboxylic acid compound is substituted with an alkyl group (hereinafter also referred to as "half ester"). Examples of preferred half esters include compounds represented by the following general formulas (B-1) to (B-6).

R in general formulas (B-1) to (B-6) each independently represents an alkyl group having 1 to 6 carbon atoms, preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and an ethyl group or Propyl group is more preferred. Further, Y in general formula (B-2) represents a group selected from the group consisting of O, C═O, or C(CF ₃ ) ₂ . The half ester can be produced by mixing an anhydride of the above-mentioned carboxylic acid compound (carboxylic anhydride) with an alcohol solvent and ring-opening the carboxylic anhydride.

Here, the amount of the crosslinking agent (B) in the solid content of the insulating material is not particularly limited, and for example, the amount of carbonyl groups derived from the crosslinking agent (B) relative to the total amount of nitrogen atoms derived from the curable resin (A) is The ratio of the total amount (total amount of carbonyl groups/total amount of nitrogen atoms) is preferably 0.1 or more and 3.0 or less. The above ratio is more preferably 0.3 or more and 2.5 or less, and even more preferably 0.4 or more and 2.2 or less. Note that the carbonyl group is a carbonyl group in imide crosslinking or amide crosslinking, in an alkyl ester, or in a carboxyl group. When the above ratio is 0.1 or more and 3.0 or less, the heat resistance of the insulating portion tends to be good.

・Additive (C)
Examples of additives include acids (c-1) having a weight average molecular weight of 46 to 195 and having a carboxy group, and bases (c-2) having no ring structure and having a weight average molecular weight of 17 to 120 and having a nitrogen atom. included. Although the additive (C) usually evaporates during the formation of the insulating part, the additive (C) or the structure derived from the additive (C) may partially remain in the insulating part.

It is thought that when the above acid (c-1) is included as the additive (C), aggregation due to association of the curable resin (A) and the crosslinking agent (B) is easily suppressed. More specifically, the interaction (for example, electrostatic interaction) between the ammonium ion derived from the amino group in the curable resin (A) and the carboxylate ion derived from the carboxy group in the acid (c-1) causes the curing. It is presumed that the aggregation is suppressed because the interaction is stronger than the interaction between the ammonium ions derived from the amino groups in the resin (A) and the carboxylate ions derived from the carboxy groups in the crosslinking agent (B).

Examples of the acid (c-1) include monocarboxylic acid compounds, dicarboxylic acid compounds, oxydicarboxylic acid compounds, etc. Specific examples include formic acid, acetic acid, malonic acid, oxalic acid, citric acid, and benzoic acid. , lactic acid, glycolic acid, glyceric acid, butyric acid, methoxyacetic acid, ethoxyacetic acid, phthalic acid, terephthalic acid, picolinic acid, salicylic acid, 3,4,5-trihydroxybenzoic acid, and the like.

The amount of acid (c-1) in the insulating material is such that the ratio of the number of carboxy groups in acid (c-1) to the total number of nitrogen atoms in curable resin (A) (COOH/N) is 0. It is preferable to adjust it so that it is .01 or more and 10 or less. The ratio is more preferably 0.02 or more and 6 or less, and even more preferably 0.5 or more and 3 or less.

On the other hand, when the above-mentioned base (c-2) is included as the additive (C), the carboxy group in the above-mentioned crosslinking agent (B) and the amino group in the base (c-2) form an ionic bond, It is presumed that aggregation due to association between the curable resin (A) and the crosslinking agent (B) is suppressed. More specifically, the interaction between the carboxylate ion derived from the carboxy group in the crosslinking agent (B) and the ammonium ion derived from the amino group in the base (c-2) causes the amino group in the curable resin (A) to It is presumed that the aggregation is suppressed because the interaction is stronger than the interaction between the derived ammonium ions and the carboxylate ions derived from the carboxy groups in the crosslinking agent (B).

Examples of the base (c-2) include monoamine compounds, diamine compounds, etc. Specific examples include ammonia, ethylamine, ethanolamine, diethylamine, triethylamine, ethylenediamine, N-acetylethylenediamine, N-(2- These include aminoethyl)ethanolamine, N-(2-aminoethyl)glycine, and the like.

The amount of base (c-2) in the insulating material is determined by the ratio (N/COOH) of the number of nitrogen atoms in the base (c-2) to the number of carboxy groups in the crosslinking agent (B). It is preferable to adjust it to 0.5 or more and 5 or less. The ratio is more preferably 0.9 or more and 3 or less.

In addition, the insulating material contains tetraethoxysilane, tetramethoxysilane, bistriethoxysilylethane, bistriethoxysilylmethane, bis(methyldiethoxysilyl)ethane, 1,1,3,3,5, 5-hexaethoxy-1,3,5-trisilacyclohexane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahydroxylcyclosiloxane, 1,1,4,4-tetramethyl- Contains 1,4-diethoxydisylethylene, 1,3,5-trimethyl-1,3,5-trimethyl-1,3,5-triethoxy-1,3,5-trisilacyclohexane or structures derived from these. It's okay to stay. When these are included, the insulation properties of the insulating part tend to increase.

The insulating material may contain a solvent other than the polar solvent (D) described below, such as n-hexane, as the additive (C). Furthermore, the insulating material may further contain phthalic acid, benzoic acid, or derivatives thereof to improve electrical properties. Furthermore, benzotriazole or a derivative thereof may be included as an additive (C). When the insulating material contains these, corrosion of the metal electrode is easily suppressed.

In addition, when using acid (c-1) as an additive, when preparing an insulating material, a mixture of acid (c-1) and curable resin (A) and a crosslinking agent (B) may be mixed. is preferred. That is, it is preferable to mix the curable resin (A) and the acid (c-1) in advance before mixing the curable resin (A) and the crosslinking agent (B). Thereby, it is possible to suppress cloudiness and gelation of the solution when the curable resin (A) and the crosslinking agent (B) are mixed. Further, when using the base (c-2) as an additive, it is preferable to mix the mixture of the base (c-2) and the crosslinking agent (B) with the curable resin (A). That is, before mixing the curable resin (A) and the crosslinking agent (B), it is preferable to mix the crosslinking agent (B) and the base (c-2) in advance. Thereby, it is possible to suppress cloudiness and gelation of the solution when the curable resin (A) and the crosslinking agent (B) are mixed.

・Polar solvent (D)
The insulating material may contain a polar solvent (D). In this specification, the polar solvent (D) refers to a solvent having a dielectric constant of 5 or more at room temperature. Examples of polar solvents (D) include protic inorganic compounds such as water and heavy water; methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, isopentyl alcohol, cyclohexanol, Alcohols such as ethylene glycol, propylene glycol, 2-methoxyethanol, 2-ethoxyethanol, benzyl alcohol, diethylene glycol, triethylene glycol, glycerin; Ethers such as tetrahydrofuran and dimethoxyethane; furfural, acetone, ethyl methyl ketone, cyclohexane, etc. aldehydes and ketones; acetic anhydride, ethyl acetate, butyl acetate, ethylene carbonate, propylene carbonate, formaldehyde, N-methylformamide, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methyl -Acid derivatives such as -2-pyrrolidone and hexamethylphosphoric acid amide; nitriles such as acetonitrile and propylonitrile; nitro compounds such as nitromethane and nitrobenzene; and sulfur compounds such as dimethyl sulfoxide. Among these, protic solvents are preferred, it is more preferred that they contain water, and it is even more preferred that they contain ultrapure water.

The amount of polar solvent (D) in the insulating material is not particularly limited, and is preferably 1.0% by mass or more and 99.99896% by mass or less, and 40% by mass or more and 99.99896% by mass or less based on the entire insulating material. More preferred. The boiling point of the polar solvent (D) is preferably 150° C. or lower, more preferably 120° C. or lower, from the viewpoint of volatilization when forming the insulating portion.

(2) Formation method of insulating part The insulating part containing the above resin is formed using the above-mentioned insulating material by vapor phase film forming methods such as vapor deposition polymerization, CVD (chemical vapor deposition) method, ALD (atomic layer deposition) method, etc.; dipping It can be formed by depositing or coating on the substrate main body by a coating method such as a method, a spray method, a spin coating method, or a bar coating method. Among these, the coating method is preferred. Among the coating methods, when forming an insulating part with a thickness of micron size, the bar coating method is preferable, and when forming an insulating part with a thickness of nano size (several nanometers to several hundred nanometers), spin coating method is preferable. is preferred. Note that the amount of the insulating material applied may be adjusted as appropriate depending on the desired thickness of the insulating portion.

When applying the insulating material by a coating method, after coating, the curable resin (A) is cured (the curable resin (A) and the crosslinking agent (B) are reacted) to form an insulating part. At this time, it is preferable to heat the coating film to remove the polar solvent (D) in the coating film or to cause the curable resin (A) and crosslinking agent (B) to react. The heating temperature is preferably 150°C to 450°C, more preferably 180°C to 400°C. The temperature refers to the temperature of the surface of the coating film. Moreover, there is no particular restriction on the pressure during heating, and an absolute pressure of 17 Pa or less is preferable. The absolute pressure is more preferably 1000 Pa or more and below atmospheric pressure, even more preferably 5000 Pa or more and below atmospheric pressure, and particularly preferably 10000 Pa or more and below atmospheric pressure. The heating can be performed in a conventional manner using a furnace or a hot plate. Further, the atmosphere during heating is not particularly limited, and may be an air atmosphere or an inert gas (nitrogen gas, argon gas, helium gas, etc.) atmosphere. Furthermore, the heating time is not particularly limited either, and is preferably 3 hours or less, more preferably 1 hour or less. In order to shorten the heating time, the surface of the coating film may be irradiated with ultraviolet (UV) light. As the ultraviolet light, ultraviolet light with a wavelength of 170 nm to 230 nm, excimer light with a wavelength of 222 nm, excimer light with a wavelength of 172 nm, etc. are preferable. In addition, when performing ultraviolet irradiation, it is preferable to perform it under an inert gas atmosphere.

(3) Physical properties of insulating part The curing rate of the insulating part obtained by curing the above-mentioned insulating material (before the above-mentioned lamination process) is preferably 70% or more from the viewpoint of suppressing misalignment between the substrates in the lamination process, It is more preferably 80% or more, even more preferably 85% or more, particularly preferably 90% or more, and even more preferably 93% or more. Further, the curing rate of the insulating portion may be 100%, 99% or less, 95% or less, or 90% or less.

Whether or not the insulating portion is hardened can be confirmed by, for example, measuring the peak intensity of specific bonds and structures using FT-IR (Fourier transform infrared spectroscopy). Specific bonds and structures include bonds and structures generated by crosslinking reactions. For example, when an amide bond, imide bond, siloxane bond, tetrahydronaphthalene structure, oxazole ring structure, etc. are formed, it can be determined that the insulating material is hardened, and the peak intensity derived from these bonds, structures, etc. is measured by FT - You can confirm by measuring with IR. The amide bond can be confirmed by the presence of vibrational peaks at about 1650 cm ⁻¹ and about 1520 cm ⁻¹ . Imide bonds can be confirmed by the presence of vibrational peaks at about 1770 cm ⁻¹ and about 1720 cm ⁻¹ . Siloxane bonds can be confirmed by the presence of vibrational peaks between 1000 cm ⁻¹ and 1080 cm ⁻¹ . The tetrahydronaphthalene structure can be confirmed by the presence of vibrational peaks between 1500 cm ⁻¹ . The oxazole ring structure can be confirmed by the presence of vibrational peaks at about 1625 cm ⁻¹ and about 1460 cm ⁻¹ .

In addition, the above curing rate is, for example, the peak intensity of specific bonds and structures in the insulating material before it is applied to the substrate body (if it has multiple peaks such as imide, amide, etc., the sum of those peak intensities). It can be confirmed by measuring by FT-IR (Fourier transform infrared spectroscopy) and determining the rate of increase or decrease in peak intensity. Note that in the case of a band-like peak that is difficult to separate, such as a siloxane bond, the maximum peak intensity may be used.

Specifically, when specific bonds and structures are generated by the curing reaction, the rate of increase in peak strength can be calculated using the following formula, and the calculated value can be taken as the curing rate of the insulating part.
Increase rate of peak strength (curing rate of insulation part) = [(peak strength of specific bonds and structures of insulating material)/(peak strength of specific bonds and structures after heating)] x 100

Note that background signal removal may be performed using a normal method. Further, the FT-IR measurement can be performed by a transmission method or a reflection method, if necessary. In the above rate of increase in peak intensity, if there are multiple bonds or structures that increase the peak intensity, the peak intensity may be read as the total intensity of the multiple peak intensities.

Further, the amount of silicon on the surface of the insulating portion is preferably 20 atomic % or less, more preferably 15 atomic % or less, and even more preferably 10 atomic % or less. It can be evaluated by measuring the atomic ratio using an X-ray photoelectron spectrometer (XPS). Specifically, using XPS (for example, AXIS-NOVA (manufactured by KRATOS)), the atomic ratio is measured from the peak intensity of the narrow spectrum when the total amount of each element detected in the wide spectrum is taken as 100%. can do.

As mentioned above, the composite modulus of elasticity of the insulating portion at 23° C. is preferably 10 GPa or less, more preferably 8 GPa or less, and even more preferably 6 GPa or less. Further, the composite modulus of elasticity of the insulating portion at 23° C. is preferably 0.1 GPa or more, more preferably 1 GPa or more, from the viewpoint of suitably suppressing misalignment of the substrate.

Further, the insulating part preferably has a functional group capable of forming a chemical bond on the surface of the insulating part, from the viewpoint of increasing the bonding strength between the first substrate and the second substrate. Examples of such functional groups include amino groups, epoxy groups, vinyl groups, silanol groups (Si-OH groups), and silanol groups are preferred from the viewpoint of heat resistance. These functional groups may be introduced by surface treatment such as plasma treatment, chemical treatment, UV ozone treatment, etc. after forming the insulating portion by the method described above, or by treatment with a silane coupling agent. Alternatively, compounds containing these functional groups may be mixed into the insulating material.

Further, it is preferable that the insulating part has a Si--OH group on the surface. Since the surface of the insulating part has a Si--OH group, temporary fixing can be performed at a low temperature when bonding the first substrate and the second substrate. Furthermore, it becomes possible to increase the bonding strength at the interface between the first substrate and the second substrate of the obtained semiconductor device. The surface energy of the bonding interface between the insulating parts of the first substrate and the second substrate is preferably 2.5 (J/m ² ) or more.

Whether or not the surface of the insulating portion has a Si—OH group can be evaluated by surface analysis of the insulating portion using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Specifically, using PHI nanoTOFII (ULVAC-PHI Co., Ltd.), which is a TOF-SIMS, it was determined whether the surface of the insulating part has Si-OH groups based on the presence or absence of a peak at a mass-to-charge ratio (m/Z) of 45. can be evaluated.

2. Semiconductor Device The semiconductor device of the present invention will be explained. A semiconductor device of the present invention includes a first substrate having a plurality of first metal electrodes and a first insulating part arranged so as to surround each of the first metal electrodes, a plurality of second metal electrodes, and each of the first metal electrodes. A second substrate having a second insulating part arranged so as to surround two metal electrodes is a semiconductor device in which the first metal electrode and the second metal electrode are stacked so as to face each other, and the first metal electrode The electrode and the second metal electrode are connected via a connection layer containing metal. Note that the thickness of the connection layer is preferably 300 nm or less, more preferably 100 nm or less.

Here, the semiconductor device can be manufactured by the above-described semiconductor device manufacturing method, but is not limited to this manufacturing method. Further, since each member is the same as each member described in the above-mentioned method for manufacturing a semiconductor device, a detailed description thereof will be omitted here. Note that the bonding layer in the semiconductor device of the present invention is a layer formed by applying and baking the above-mentioned conductive ink.

In the following, the invention will be explained with reference to examples. The scope of the present invention is not interpreted to be limited by the Examples.

(Example)
・Preparation of insulating material As a curable resin, 2 g of hydrolyzate of 3-aminopropyldiethoxymethylsilane (3APDES; (3-Aminopropyl)diethoxymethylsilane) was prepared, and as a crosslinking agent, pyromellitic acid half ester (the following general formula ( B-1) in which R is an ethyl group) was prepared. These were added to 96.4 g of a mixed solution of water, ethanol, and 1-propanol (water:ethanol:1-propanol=31.3:31.7:33.4, mass ratio) to prepare an insulating material.

- Preparation of first and second substrates Cylindrical copper electrodes (diameter 22 μm, height 2.8 μm, pitch 40 μm) were formed on a silicon substrate body and cut into a size of 50 mm×50 mm. After that, place it on a spin coater so that the surface on which the copper electrode was formed is vertically upward, drop 2.0 mL of insulating material at a constant speed for 10 seconds, hold it for 23 seconds, then run at 2000 rpm for 1 second, then at 600 rpm. After rotating for 30 seconds, it was dried by rotating at 2000 rpm for 10 seconds. The substrate body coated with the insulating material was heated at 200° C. for 30 minutes in a nitrogen atmosphere. As a result, an insulating part (an insulating part having a thickness of 2.8 μm in the area where the copper electrode is not formed and a composite elastic modulus of 5.8 GPa at 23° C.) was formed. An insulating part was also formed on the copper electrode. Similarly, a substrate having a substrate body, a metal electrode, and an insulating part was prepared.The composite elastic modulus was tested using a nanoindentator (trade name TI-950 Tribo Indenter, manufactured by Hysitron, Berkovich type indenter). The unloading-displacement curve was measured at 23°C under the condition of a depth of 20 nm, and the maximum load and maximum The composite elastic modulus at 23° C. was calculated from the displacement.

The above two substrates were polished with a silica compound slurry (COMPOL80 (manufactured by Fujimi Incorporated)) using a CMP device (ARW-8C1MS (manufactured by M.A.T.)) to remove the insulating material on the copper electrodes. was removed to expose the copper electrode. Then, the substrate after CMP was cleaned with a post-CMP cleaning solution (CMP-B01 (manufactured by Kanto Kagaku Co., Ltd.)). After CMP, the thickness of the insulating part in the area where the copper electrode was not formed was 2.4 μm, and the surface roughness (Ra, measured with a scanning probe microscope) of the insulating part was 0.60 nm. In addition, when the level difference between the surface of the insulating part and the exposed copper electrode was measured using a contact type surface level difference meter (Profilometer P16+ (manufactured by KLA Tencor)), it was found that the copper electrode was 60 nm convex from the surface of the insulating part. It had become.

Subsequently, the copper electrode was polished with a slurry containing hydrogen peroxide and silica, and the substrate after CMP was cleaned with a post-CMP cleaning solution (CMP-B01 (manufactured by Kanto Kagaku Co., Ltd.)). After CMP, the thickness of the insulating portion in the region where the copper electrode was not formed was 2.3 μm. Further, when the level difference between the insulating part and the exposed copper electrode was measured using a contact type surface level difference meter, it was found that the copper electrode was recessed by 100 nm from the surface of the insulating part. These were designated as a first substrate and a second substrate.

- Application of conductive inkjet ink As the conductive ink, an ink containing a copper formate complex or a complex and metal nanoparticles (manufactured by Mitsui Chemicals) was prepared. The conductive ink was filled into an ink tank of an inkjet device manufactured by Epson Corporation, and applied onto the metal electrode of the first substrate at a coating amount of 0.5 μg/dot per unit area.

-Lamination of the first substrate and the second substrate The above-described first substrate and second substrate were opposed to each other with the conductive ink interposed therebetween so that the metal electrodes faced each other.

- Firing of conductive ink The first substrate and the second substrate were heated at 250° C. for 15 minutes while facing each other.

(Comparative example)
A first substrate and a second substrate were prepared in the same manner as in the above example. Then, these were heated at 250° C. for 15 minutes while being pressed under a pressure of 350 N, and the metal electrodes were diffusion bonded to each other to obtain a semiconductor device.

(result)
When the state of bonding between the metal electrodes of the obtained semiconductor device was evaluated using a cross-sectional SEM image, bonding between the metals was observed in the example, and no bonding was observed in the comparative example.

According to the method for manufacturing a semiconductor device of the present invention, two substrates having metal electrodes can be bonded together at low temperature and pressure, and a semiconductor device can be manufactured efficiently. Therefore, it is very useful when manufacturing various semiconductor devices.

10 First substrate 11 First metal electrode 12 First insulating section 13 First substrate body 20 Second substrate 21 Second metal electrode 22 Second insulating section 23 Second substrate body 110, 120 Substrate 111, 121 Metal electrode 112, 122 Insulation section

Claims (3)

A first substrate having a plurality of first metal electrodes and a first insulating part arranged so as to surround each of the first metal electrodes, and a plurality of second metal electrodes and a first insulating part that surrounds each of the second metal electrodes. preparing a second substrate having a second insulating portion disposed thereon;
applying conductive ink on the first metal electrode and/or the second metal electrode by an inkjet method;
stacking the first substrate and the second substrate so that the first metal electrode and the second metal electrode face each other with the conductive ink or a solidified product thereof interposed therebetween;
baking the conductive ink or its solidified product by heating;
A method for manufacturing a semiconductor device, including: The temperature in the step of firing the conductive ink or its solidified product is 120°C or more and 300°C or less,
A method for manufacturing a semiconductor device according to claim 1. the first metal electrode and/or the second metal electrode contain copper;
A method for manufacturing a semiconductor device according to claim 1 or 2.

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