JP2007250966A - Filler and substrate using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filler to be easily drilled without generating adhesion defects or cracks between the filler and a substrate. <P>SOLUTION: The filler to be filled in at least one of a through-hole and a recess on the substrate contains at least a curing agent, an inorganic filler, an organic filler, and a liquid resin. Further, the filler is prepared characteristically in the form of liquid. By the filler, the linear thermal expansion coefficient difference of the substrate and the cured filler is low and the elastic modulus of excellent drilling workability is attained. Thus, the generation of the adhesion defects is suppressed between the substrate and the filler generated by the difference in the linear thermal expansion coefficient and the cracks by the elastic modulus. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate in which at least one of a through hole and a recess formed in a substrate is filled and cured, and a processing hole is provided in a filled portion of the cured filler.

In recent years, with the development of information communication technology represented by the Internet and the dramatic improvement in the processing speed of information processing apparatuses, there is an increasing need for transmitting and receiving large-capacity data such as images. An information transmission speed of 10 Gbps or higher is desirable to exchange such a large amount of data freely through an information communication facility, and great expectations are placed on optical communication technology as a technology that can realize such a high-speed communication environment. On the other hand, signals can be transmitted at high speeds even on signal transmission paths at relatively short distances, such as connections between wiring boards in equipment, connections between semiconductor chips in wiring boards, connections within semiconductor chips, etc. It has been desired in recent years. For this reason, it is thought that it is ideal to shift from a conventional metal cable or metal wiring to optical transmission using an optical fiber or an optical waveguide.

  Conventionally, a wiring board that mounts an optical element and performs optical communication between the optical element and an optical fiber or an optical waveguide has been proposed (see Patent Documents 1 and 2).

JP 2002-236228 A

JP 2003-107283 A

  Patent Document 1 discloses a technique in which an external board and a wiring board can be arranged at predetermined positions by a self-alignment action when an external board on which an optical element is mounted is connected to the wiring board by solder bumps and reflowed. Is disclosed. However, in the technique disclosed in Patent Document 1, alignment (optical axis alignment) between the external substrate on which the optical element is mounted and the wiring substrate is merely performed by solder reflow. For this reason, the alignment accuracy is not sufficient, and an optical axis shift is likely to occur between the optical element and the optical waveguide, which in turn tends to cause a light transmission loss. Therefore, it is considered that this method cannot sufficiently cope with the higher speed and higher density expected in the future.

  In addition, in the structure of the optical element mounting substrate, a technique for aligning the optical axis of an optical element, fiber, waveguide, etc. by an alignment method using a guide pin with a precision hole as a reference like an optical connector has been proposed. However, in the above technique, with an inorganic material substrate such as a ceramic substrate, precise drilling is technically and costly difficult. In addition, when a resin substrate is used, there is a possibility that the emission wavelength is deviated as a result of poor heat dissipation of the light emitting element and the operating circuit. Therefore, as in Patent Document 2, there is proposed a structure in which a cylindrical portion is formed of a resin with a substrate formed of a ceramic having a plurality of cylindrical portions.

  In the above-mentioned Patent Document 2, the difference in linear thermal expansion coefficient between the inorganic material substrate and the filler filled in the cylindrical portion, the poor adhesion between the filler and the inorganic material substrate caused by the shrinkage at the time of curing of the filler, and the filler In order to prevent cracks in the inorganic material substrate, an inorganic filler is contained in the filler to reduce the difference in linear thermal expansion coefficient. However, the decrease in the coefficient of linear thermal expansion coefficient due to the inorganic filler alone is a problem that the inorganic filler accelerates wear during drilling, a problem that cracks occur due to an increase in the elastic modulus of the cured filler, and further curing. Since the viscosity of the previous filler also increases, the problem that the filling workability deteriorates occurs. Moreover, what fills a metal mold | die at high temperature like the solid sealing agent has the problem that a metal mold | die and an apparatus cost start.

  The present invention relates to a filling material filled in at least one of a through hole and a recess formed in a substrate that requires positioning such as an optical element mounting substrate for accurate alignment without optical axis misalignment. An object of the present invention is to provide a filler that does not cause poor adhesion and cracks between the material and the substrate and is easy to drill. Another object of the present invention is to provide a substrate in which the filler is filled and cured in at least one of a through hole and a recess formed in the substrate, and the filler is provided with a hole. .

  As a means for solving the above-mentioned problem, it is a filler that fills at least one of the through-hole and the recess formed in the substrate, and contains at least a curing agent, an inorganic filler, an organic filler, and a liquid resin, In addition, there is a filler characterized in that the filler is liquid.

  Therefore, according to this means, by including not only the inorganic filler but also the organic filler that relieves stress, the filler has a low difference in linear thermal expansion coefficient between the substrate and the cured filler, and a good elastic modulus. It can be. Therefore, it is possible to suppress the occurrence of cracks due to poor adhesion between the substrate and the filler caused by the difference in linear thermal expansion coefficient and the increase in elastic modulus. Further, the addition of the organic filler makes it possible to suppress the curing shrinkage of the resin with the smallest possible addition amount of the inorganic filler. Therefore, good workability can be obtained without increasing the viscosity of the filler. Furthermore, a sealing agent that uses a solid filler fills the mold at a high temperature, which requires a mold and an apparatus cost. However, the liquid filler of the present invention does not require a mold and the apparatus cost is high. It does not take. In addition, since it is a liquid filler, even better workability can be obtained.

  The filler of the present invention is preferably a ceramic filler or a metal filler as the inorganic filler. Examples of the ceramic filler include silica, alumina, talc, calcium carbonate, and aluminum nitride. Examples of the metal filler include copper, silver, and an alloy of copper and silver. Among these, it is particularly preferable to use a ceramic filler. Ceramic filler can cope with lower thermal expansion than metal filler, and it is easy to control. Moreover, it is because it is easy to obtain the filler of the stable shape compared with a metal filler.

  Furthermore, a silica filler is preferable among ceramic fillers. The reason for this is that when silica filler is used, the difference between the linear thermal expansion coefficient of the cured filler and the linear thermal expansion coefficient of the substrate is particularly low, so that poor adhesion caused by the difference in linear thermal expansion coefficient is suppressed. . Note that the elastic modulus of the filler that provides good adhesion between the substrate and the cured filler when using only the inorganic filler without using the organic filler as the filler is 8.1 GPa.

  The inorganic filler of the filler may be used alone or in combination with other inorganic fillers.

  The filler of the present invention preferably uses silicone as the organic filler. Silicone includes rubber and resin, but it is more preferable to contain rubber silicone. By using rubber silicone, the elastic modulus of the filler is lowered and the shrinkage during curing of the filler is alleviated, so that the generation of cracks between the substrate and the filler can be suppressed. In addition, when at least one of the through hole and the concave portion of the substrate is filled with a filler, the filler is cured, and a machining hole is provided in the filling portion of the filler with a drill or the like, precise processing is easily performed.

  Furthermore, it is more preferable to use an organic filler in which the surface of rubber silicone is coated with resin silicone. By coating the surface of the rubber silicone with the resin silicone, in addition to the above effects of the rubber silicone, the heat resistance effect of the resin is added.

  The organic filler has an effect of lowering the elastic modulus, but usually the linear thermal expansion coefficient is increased by addition. However, when the silica filler and the organic filler are used in combination, an increase in the linear thermal expansion coefficient due to the addition of the organic filler is suppressed, or conversely, the linear thermal expansion coefficient is lowered. This tendency varies depending on the type of organic filler. When silicone is used as the organic filler, when the silica filler ratio is 30 to 70 vol% (especially 40 to 60 vol%) with respect to 100 vol% of the total volume of the filler, silicone is added in a certain amount of silica filler. As a result, the linear thermal expansion coefficient of the filler decreases.

  Therefore, by using silicone in the amount of silica filler in the above range, the difference in coefficient of linear thermal expansion between the substrate and the filler can be reduced and the elastic modulus can be lowered. Therefore, it is possible to solve the problems of adhesion failure caused by a difference in linear thermal expansion coefficient, suppression of generation of cracks due to a high elastic modulus, and premature wear during drilling with an inorganic filler.

  Moreover, when the filler is used in an amount of 30 to 70 vol% (especially 40 to 60 vol%) and a silicone resin of 3 to 15 vol% (especially 5 to 10 vol%) with respect to 100 vol% of the total volume of the filler, the substrate is filled The difference in coefficient of linear thermal expansion from the material is 30 ppm / K or less, and the elastic modulus of the cured filler is 1 GPa or more and 8 GPa or less. Particularly, the adhesion between the substrate and the filler is good, cracks do not occur, and drilling Workability is also good. Further, if the volume ratio of the silica filler and the silicone resin is changed and the linear thermal expansion coefficient is made larger than the above range, poor adhesion occurs. Furthermore, if the volume ratio of the silica filler and the silicone resin is changed and the elastic modulus is made smaller than the above range, it becomes difficult to form holes with high accuracy provided in the filler, and if the elastic modulus is made larger than the above range, cracks are generated. End up.

  The resin component of the filler of the present invention is preferably a liquid resin. In particular, it is preferable to use a bisphenol-type epoxy resin, a glycidylamine-type epoxy resin, a phenol novolac-type epoxy resin, a glycidyl ether-type epoxy resin, a glycidyl ester-type epoxy resin, or the like that is liquid at least at a temperature of 20 to 30 ° C. Among these, bisphenol type epoxy resins are more preferable.

  As the resin component of the filler, a bisphenol type epoxy resin may be used alone, or the epoxy resin described above may be used in combination.

  Examples of the bisphenol type epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin and the like. Among these, bisphenol A type epoxy resin and bisphenol F type epoxy resin are preferable. Bisphenol A-type epoxy resins and bisphenol F-type epoxy resins are most preferable in view of heat resistance, chemical resistance, fluidity, and the like. Furthermore, since the viscosity is low, the filling property is excellent when used as a filler. Because.

  The filler of the present invention also contains a curing agent. As the curing agent, dicyandiamide is preferably used. When a filler using dicyandiamide as a curing agent is cured, the heat resistance, chemical resistance, and corrosion resistance against an oxidizing agent, a base, and the like are excellent, and further, a life that can be stably used is extended.

  Generally, when a curing agent is mixed with a resin, curing progresses even during the storage period, so that the lifetime that can be used stably becomes short. However, according to the curing agent containing dicyandiamide of the present invention, there is little change with time after mixing the epoxy resin and the curing agent, and the life is prolonged. Furthermore, since the curing shrinkage of the epoxy resin is suppressed, the amount of inorganic and organic filler added can be reduced, and the viscosity of the filler does not increase. Therefore, in this invention, workability | operativity becomes favorable by using the hardening | curing agent containing dicyandiamide.

  Moreover, you may add a curing catalyst, an antifoamer, etc. to the filler of this invention.

  Further, one of the present inventions is a substrate in which at least one of through holes and recesses formed in the substrate is filled and cured with the filler of the present invention, and then the filler is provided with holes.

  According to the above substrate, since the liquid and low-viscosity filler is filled in at least one of the through hole and the concave portion, the filler is not mixed into the at least one of the through hole and the concave portion of the substrate. Can be filled. In addition, since a filling material having an elastic modulus of 1 GPa or more and 8 GPa or less is filled and cured, and a processing hole is provided by drilling, punching, or laser processing, a highly accurate hole can be formed. The hole provided in the filler may be a through hole or a blind hole (concave part).

  As the substrate, for example, a resin substrate, a ceramic substrate, a glass substrate, a metal substrate, or the like can be used, and a ceramic substrate is particularly preferable. When a ceramic substrate having a higher thermal conductivity than that of the resin substrate is used, heat generated from the optical element and its operation circuit is efficiently dissipated. Therefore, the shift of the emission wavelength due to the deterioration of the heat dissipation property is avoided, and an optical element mounting substrate excellent in operational stability and reliability can be realized.

  Preferable examples of such ceramic substrates include substrates made of alumina, alumina nitride, silicon nitride, boron nitride, beryllia, mullite, low-temperature fired glass ceramic, glass ceramic and the like. Among these, a substrate using alumina or alumina nitride is particularly preferable.

  Moreover, as a suitable example of a resin substrate, the board | substrate which consists of EP resin (epoxy resin), PI resin (polyimide resin), BT resin (bismaleide-tridian resin), PPE resin (polyphenylene ether resin) etc. is mentioned, for example. it can. In addition, a substrate made of a composite material of these resins and organic fibers such as glass fibers (glass woven fabric or glass nonwoven fabric) or polyimide fibers may be used.

  Preferable examples of the metal substrate include a copper substrate, a substrate made of a copper alloy, a substrate made of a simple metal other than copper, and a substrate made of an alloy other than copper.

  Another embodiment of the substrate of the present invention includes a substrate provided in a filler and having an external terminal attached to a hole.

  According to the above substrate, since a filler having an elastic modulus of 1 GPa or more and 8 GPa or less is used, attachment is possible even when the diameter of the external terminal is larger than the diameter of the hole formed in the filler, and It is firmly held in the hole formed in the filler. As a result, since the external terminal can be attached with high accuracy, the optical element can be mounted on the substrate with reference to the external terminal.

  The present invention will be specifically described below with reference to examples. The compounds used in Examples and Comparative Examples are as follows.

  As the resin component of the filler, bisphenol A type epoxy resin (made by Japan Epoxy Resin, trade name: Epicoat 828), bisphenol F type epoxy resin (made by Japan Epoxy Resin, trade name: Epicoat 807), aminophenol (Japan Epoxy Resin) Manufactured, trade name: Epicoat 630).

  As the curing agent, a dicyandiamide curing agent (manufactured by Japan Epoxy Resin, trade name: DICY7) and an imidazole curing agent (manufactured by Japan Epoxy Resin, trade name: 2P4MHZ) were used.

  As the inorganic filler, a spherical SiO 2 powder (manufactured by Tatsumori) having an average particle diameter of 5 μm and a maximum particle diameter of 24 μm, which is a silica filler, was used.

  As the organic filler, silicone composite powder (made by Shin-Etsu Silicone, trade name: KMP-600) which is a silicone resin was used.

  First, each raw material was weighed so that the blending ratio shown in Table 1 was obtained, placed in a container and stirred, kneaded with a three-roller, then vacuum degassed to adjust the filler. As an example of the present invention, a filler having the prepared composition of Examples 1 to 4 was prepared, and a filler having a prepared composition of Comparative Examples 1 to 5 was prepared for comparison with the examples of the present invention. did. In Table 1, the amount of each raw material added is shown in parts by weight (hereinafter referred to as wt%), where the total amount is 100. In addition, the amount of silica filler and the amount of silicone composite powder are separately shown as a volume ratio (hereinafter, vol%) with the total volume of the filler being 100.

  In Example 1, 21 wt% of bisphenol A type epoxy resin as epoxy resin, 12 wt% of aminophenol, 61 wt% of silica filler as inorganic filler, 3 wt% of silicone composite powder as organic filler, and dicyandiamide type curing agent as curing agent Is a filler material to which 1 wt% is added. Moreover, the volume ratio of a silica filler is 45 vol%, and the volume ratio of a silicone composite powder is 5 vol%.

  In Example 2, 20 wt% of bisphenol A type epoxy resin as epoxy resin, 10 wt% of aminophenol, 62 wt% of silica filler as inorganic filler, 6 wt% of silicone composite powder as organic filler, and dicyandiamide type curing agent as curing agent It is a filler with 1 wt% added. The volume fraction of the silica filler is 45 vol%, and the volume ratio of the silicone composite powder is 10 vol%.

  In Example 3, 16 wt% of bisphenol A type epoxy resin as epoxy resin, 9 wt% of aminophenol, 70 wt% of silica filler as inorganic filler, 3 wt% of silicone composite powder as organic filler, and dicyandiamide type curing agent as curing agent Is a filler material to which 1 wt% is added. Moreover, the volume ratio of a silica filler is 55 vol%, and the volume ratio of a silicone composite powder is 5 vol%.

  Example 4 is 21 wt% bisphenol F type epoxy resin as an epoxy resin, 12 wt% aminophenol, 61 wt% silica filler as an inorganic filler, 3 wt% silicone composite powder as an organic filler, and a dicyandiamide type curing agent as a curing agent. Is a filler material to which 1 wt% is added. Moreover, the volume ratio of a silica filler is 45 vol%, and the volume ratio of a silicone composite powder is 5 vol%.

  Comparative Example 1 is an organic filler added with 23 wt% of bisphenol A type epoxy resin as an epoxy resin, 13 wt% of aminophenol, 61 wt% of silica filler as an inorganic filler, 1 wt% of dicyandiamide type curing agent as a curing agent, and the like. It is a filler agent to which is not added. The volume fraction of the silica filler is 45 vol%.

  Comparative Example 2 is an organic filler in which 16 wt% of bisphenol A type epoxy resin as an epoxy resin, 10 wt% of aminophenol, 70 wt% of silica filler as an inorganic filler, 1 wt% of dicyandiamide type curing agent as a curing agent, etc. It is a filler agent to which is not added. The volume fraction of the silica filler is 55 vol%.

  Comparative Example 3 is an organic filler added with 13 wt% of bisphenol A type epoxy resin as an epoxy resin, 7 wt% of aminophenol, 78 wt% of silica filler as an inorganic filler, 1 wt% of dicyandiamide type curing agent as a curing agent, and the like. It is a filler agent to which is not added. The volume fraction of the silica filler is 65 vol%.

  In Example 4, 34 wt% of bisphenol A type epoxy resin as an epoxy resin, 19 wt% of aminophenol, 42 wt% of silicone composite powder as an organic filler, 2 wt% of dicyandiamide type curing agent as a curing agent, and the like are added. It is a filler with no filler added. The volume ratio of the silicone composite powder is 45 vol%.

  In Example 5, 17 wt% of bisphenol A type epoxy resin as epoxy resin, 9 wt% of aminophenol, 60 wt% of silica filler as inorganic filler, 12 wt% of silicone composite powder as organic filler, and imidazole curing agent as curing agent Is a filler material to which 1 wt% is added. Moreover, the volume ratio of a silica filler is 45 vol%, and the volume ratio of a silicone composite powder is 20 vol%.

  Next, a test sample was prepared according to the following procedure. Five ceramic green sheets having through-holes with an inner diameter of 1.2 mm were overlapped with the positions of the through-holes, a lamination pressure bonding process was performed, and then a firing process was performed. As a result, an alumina substrate having a thickness of 1.2 mm and a filling hole having an inner diameter of 1.0 mm was obtained.

  Next, the alumina substrate was filled with a filler and cured. Thereafter, the surface of the alumina substrate was polished to flatten the surface of the alumina substrate to obtain a test sample filled with resin.

Using the test sample, an adhesion test between the substrate and the filler, a workability test when filling the filler, and a reliability test were performed. The glass transition temperature (Tg), linear thermal expansion coefficient (CTE), and elastic modulus (E ′), which are physical properties of the filler, were also measured.
The test results and the measurement results of the physical properties of the filler are shown in Tables 1 and 2. Moreover, the said test method and the measuring method of the physical property of a filler are as follows.

  In the adhesion test with the substrate, a red solution was applied to one side of the test sample, sucked from the opposite side, and it was inspected whether the red solution leaked to the opposite side. What the red solution leaked out was judged as poor adhesion between the filler and the alumina substrate.

  In the workability test, when the alumina substrate was filled with a printing filler, the filling condition of the filler was confirmed. That is, the filler having a high viscosity and not smoothly extending was marked with x.

  In the reliability test, a test sample was placed in a pressure cooker test apparatus and tested at 121 ° C. and 100% RH for 168 hours. The hole pitch between two points before and after the test was compared with a high precision measuring device. In addition, the hole pitch after the test was confirmed (a total of 8 pairs each including 2 holes), and a deviation of ± 3 μm or more was counted.

  The linear thermal expansion coefficient is measured by casting a test sample into a film and thermally curing it at 150 ° C. for 5 hours to obtain a film-like cured body having a thickness of 100 μm. From this, a test piece having a width of 5 mm is cut out and subjected to TMA measurement. Here, “TMA” refers to thermomechanical analysis, for example, that defined in JPCA-BU01. The measurement conditions were a span of 15 mm, a 5 g tensile load applied in the longitudinal direction of the test piece, cooling to −55 ° C., heating to 270 ° C. at a heating rate of 10 ° C./min, Measure the linear thermal expansion coefficient α (see Equation 2 below). Moreover, it was 9 (ppm / k) when the linear thermal expansion coefficient of the alumina substrate was measured.

For the measurement of the elastic modulus, the test sample is cast into a film and thermally cured to obtain a cured film having a thickness of 100 μm. From this, a test piece having a width of 4 mm is cut out and subjected to DMA measurement. “DMA” here refers to dynamic viscoelastic analysis, for example, JIS.
This is defined in C 6481. The measurement conditions are as follows: From a state in which a tensile load of 10 g is applied in the longitudinal direction of the test piece with a span of 40 mm, a sine wave is applied in the longitudinal direction at an amplitude of 16 μm and a frequency of 11 Hz to obtain a storage elastic modulus at 25 ° C. Elastic modulus.

  The glass transition temperature is measured by measuring loss tangent (tan δ) by DMA measurement. The peak temperature of the loss tangent is defined as the glass transition temperature.

  As shown in Table 1, the fillers of Examples 1 to 4 were in a liquid state at normal temperature and had good paste properties, that is, workability. In addition, even after curing of the fillers of Examples 1 to 4, cracks due to the difference in coefficient of linear thermal expansion with the alumina substrate do not occur, good drillability is obtained, and in the reliability test, There was no problem.

  In Examples 1 to 4, cracks were not generated between the substrate and the filler, although the linear thermal expansion coefficient was as high as 20 to 27. This is because since the silicone composite powder that is an organic filler contains, the generated stress is relieved by the elasticity during shrinkage when the filler is cured, and the shrinkage is suppressed.

  As shown in Table 2, Comparative Example 1, which is a filler that does not contain an organic filler, has good paste properties, that is, workability, good drillability, and no problem in reliability testing. It was. However, since the linear thermal expansion coefficient of the filler was high, a gap was confirmed between the cured filler and the substrate, and poor adhesion was confirmed.

  The filler of Comparative Example 2 is a filler obtained by reducing the proportion of the bisphenol-type epoxy resin and increasing the proportion of silica filler that is an inorganic filler with respect to the filler of Comparative Example 1. As shown in Table 2, the linear thermal expansion coefficient was decreased due to the increase in the silica filler ratio, but a gap was confirmed between the hardened filler and the substrate, and poor adhesion was confirmed. Further, defects were confirmed in the reliability test.

  The filler of Comparative Example 3 is a filler obtained by reducing the proportion of the bisphenol type epoxy resin and increasing the proportion of the silica filler that is an inorganic filler with respect to the filler of Comparative Example 2. As shown in Table 2, an increase in the silica filler ratio results in a paste with a high viscosity, which makes it difficult to fill, while it is difficult to work, while the linear thermal expansion coefficient has decreased and the space between the cured filler and the substrate is reduced. No poor adhesion was confirmed. However, a defect was confirmed in the reliability test.

  As shown in Table 2, Comparative Example 4, which is a filler not containing an inorganic filler, was difficult to fill because of a paste having a high viscosity, and a defect was also confirmed in a reliability test. Although the linear thermal expansion coefficient was a very high value of 76 ppm / K, no adhesion failure was observed between the cured filler and the substrate. This is because the silicone composite powder, which is an organic filler, relaxes shrinkage during curing, as described in the examples.

  Comparative Example 5 is a filler using an imidazole curing agent without using a dicyandiamide curing agent as a curing agent. As shown in Table 2, the filler of Comparative Example 5 was difficult to fill due to the paste having a high viscosity, but no adhesion failure was confirmed. However, defects were confirmed in the reliability test.

  The filler according to the present invention is filled and cured in at least one of the through-hole and the recess formed in the substrate, and after the filler is cured, the filler is provided with holes. As a featured substrate, there is a substrate as shown in FIG. FIG. 1 is a view of the substrate 1 as viewed from above, and through holes are formed through the upper and lower surfaces of the substrate at the four corners of the upper surface of the substrate, and the filler 2 of the present invention is filled in the through holes and cured. The substrate is provided with a through hole 3 penetrating from the top surface of the substrate to the bottom surface of the substrate. FIG. 2 shows a substrate according to another embodiment of the present invention, and FIG. 2 is a view of the substrate 11 as viewed from the top. The substrate 11 is provided with a notch 13, in other words, a notch, from the substrate top surface to the substrate bottom surface. It is. The notch 13 may be semicircular or polygonal as shown in FIG. In addition, after forming a notch part as a through-hole in a multi-piece board | substrate, it is good to divide | segment into an individual piece by cutting and to form as a notch part. This is because if it is manufactured as a multi-piece substrate, it is excellent in mass productivity. Moreover, the notch part may be formed only for a specific layer thickness without penetrating the upper and lower surfaces of the substrate.

  An example of a substrate having external terminals attached to holes formed in the filler of the present invention is a substrate as shown in FIG. FIG. 3 is a cut surface obtained by cutting the upper and lower surfaces of the substrate 21 with the external terminals 24 attached to the through holes 3 of FIG. 1 along the line aa in FIG. FIG. 4 is a cut surface obtained by cutting the upper and lower surfaces of the substrate 31 along the line aa in FIG. 1 from the substrate 31 in which the external terminals 34 having different shapes from the external terminals 24 in FIG. The external terminal may be an MT pin as shown in FIG. 3, a rivet as shown in FIG. 4, or an external terminal such as a screw.

  As described above, since the filler of the present invention contains not only an inorganic filler but also an organic filler, filling without causing poor adhesion and cracking between the filler and the substrate and easy to drill. Material can be provided.

It is a schematic top view of the board | substrate with which the filler of this invention was filled and hardened and the hole was provided in the filler. FIG. 2 is a schematic top view of another embodiment different from FIG. 1 of a substrate filled and cured with the filler of the present invention and provided with holes in the filler. It is a schematic sectional drawing of the board | substrate which attached the external terminal to the hole provided in the filler of this invention. It is a schematic sectional drawing of a different aspect from FIG. 3 of the board | substrate which attached the external terminal to the hole provided in the filler of this invention.

Explanation of symbols

1, 11 ... Substrate 2, 12, 22, 32 ... Filler 3, 13 ... Through-hole 21, 31 ... Filler hole is filled and cured, and external terminals are attached to the filler holes. Boards 24, 34 ... external terminals

Claims (7)

  A filler filled in at least one of the through hole and the recess formed in the substrate, containing at least a curing agent, an inorganic filler, an organic filler, and a liquid resin, and the filler is in a liquid state Characteristic filler.   The filler according to claim 1, wherein the organic filler contains at least silicone.   The filler according to claim 1 or 2, wherein the liquid resin contains a bisphenol-type epoxy resin, and the curing agent contains a dicyandiamide-based curing agent.   The filler according to any one of claims 1 to 3, wherein the inorganic filler contains at least a silica filler.   5. The filler according to claim 4, wherein the cured filler has a difference in coefficient of linear thermal expansion from the substrate of 30 ppm / K or less and an elastic modulus of 1 GPa to 8 GPa.   The filler according to any one of claims 1 to 5 is filled and cured in at least one of a through hole and a recess formed in the substrate, and the filler is provided with a hole. A substrate characterized by being made.   The board | substrate of Claim 6 WHEREIN: The external terminal is attached to the hole formed in the said filler. The board | substrate characterized by the above-mentioned.