Interposer substrate, method for manufacturing interposer substrate, core substrate, and method for manufacturing core substrate

Abstract

Provided are an interposer substrate and a core substrate having low dielectric characteristics (relative dielectric constant, dielectric loss tangent) and high laser machining characteristics.　An interposer substrate according to the present invention is characterized by containing glass and SiO2 crystals.

Description

Interposer substrate, interposer substrate manufacturing method, core substrate, and core substrate manufacturing method

[0001] The present invention relates to an interposer substrate and a core substrate intended to connect semiconductor elements such as memory chips and logic chips to a wiring board (motherboard) with a coarse wiring pitch.

[0002] As semiconductor products become more sophisticated, wiring patterns are becoming finer, but the more miniaturized they become, the lower the yield and the higher the manufacturing costs. Furthermore, in monolithic chips, where all functions are contained in a single chip, the wiring pattern must be matched to the high-performance CPU, which causes costs to rise. If different types of chips can be mixed on a single substrate, each chip can be manufactured using the optimal manufacturing process and then mounted on a single substrate, reducing costs. The substrates required for this mixing of different types of chips are interposer substrates and core substrates.

[0003] JP 2006-286853 A JP 2015-146410 A

[0004] Interposer substrates and core substrates are made of materials such as silicon, resin, and glass, but each has its own issues (see Patent Documents 1 and 2). Silicon has high dielectric loss and is not suitable for mounting semiconductors for high-frequency applications. Resin has a low dielectric constant, but its dielectric loss is greater than that of inorganic materials. Glass has issues such as cracks occurring when creating through-holes using laser processing.

[0005] An object of the present invention is to provide an interposer substrate and a core substrate that have low dielectric properties (dielectric constant, dielectric loss tangent) and high laser processability.

[0006] As a result of various experiments, the inventors found that glass and SiO ２ The inventors have found that the above technical problems can be solved by combining glass and SiO crystals, and have proposed this invention. ２ It is characterized by containing crystals.

[0007] The interposer substrate of the present invention is a glass having a composition of, in mol %, Li ２O + Na ２ O+K ２ O 0.1 to 2% and, in molar ratio, Li ２ O / (Li ２ O + Na ２ O+K ２ O) 0.35-0.65, Na ２ O / (Li ２ O + Na ２ O+K ２ O) 0.25-0.55, K ２ O / (Li ２ O + Na ２ O+K ２ O) is preferably 0.025 to 0.2. ２ O + Na ２ O+K ２ "O" is Li ２ O, Na ２ O and K ２ The total amount of Li and O. ２ O / (Li ２ O + Na ２ O+K ２ O) is Li ２ The content of O is Li ２ O, Na ２ O and K ２ The value is divided by the total amount of Na ２ O / (Li ２ O + Na ２ O+K ２ O) is Na ２ The content of O is Li ２ O, Na ２ O and K ２ The value is divided by the total amount of O. ２ O / (Li ２ O + Na ２ O+K ２ O) is K ２ The content of O is Li ２ O, Na ２ O and K ２ This is the value divided by the total amount of O.

[0008] The interposer substrate of the present invention has a glass content of 50 to 98 mass % and SiO ２ The content of the crystals is preferably 2 to 50% by mass.

[0009] The interposer substrate of the present invention has a glass content of 50 to 96 mass % and SiO ２ It is preferable that the content of the crystals is 2 to 48 mass % and the content of the cordierite is 2 to 48 mass %.

[0010] The interposer substrate of the present invention preferably has a thermal expansion coefficient of 3 to 8 ppm / ° C. The "thermal expansion coefficient" refers to a value measured with a thermomechanical analyzer in a temperature range of 30 to 380° C.

[0011] The interposer substrate of the present invention preferably has a relative dielectric constant of 3.5 to 6 at 16 GHz.

[0012] The interposer substrate of the present invention preferably has a dielectric loss tangent of 0.003 or less at 16 GHz.

[0013] The "relative permittivity" and "dielectric loss tangent" refer to values ​​measured at a measurement temperature of 25°C and a frequency of 16 GHz based on the method for measuring microwave dielectric properties of fine ceramic substrates (JIS R1641).

[0014] The core substrate of the present invention is made of glass and SiO ２ It is characterized by containing crystals.

[0015] The method for manufacturing an interposer substrate of the present invention is a method for manufacturing an interposer substrate by using a glass powder and SiO ２ The method is characterized in that a slurry containing a mixed powder of crystalline powders is slip-cast to obtain a molded body, and then the molded body is dried and fired to obtain an interposer substrate.

[0016] In the method for producing an interposer substrate of the present invention, it is preferable to form through holes in the fired interposer substrate by laser processing.

[0017] The method for producing a core substrate of the present invention is a method for producing a core substrate by mixing glass powder and SiO ２ The method is characterized in that a slurry containing a mixed powder of crystalline powders is slip-cast to obtain a molded body, and then the molded body is dried and fired to obtain a core substrate.

[0018] In the method for producing a core substrate of the present invention, it is preferable to form through holes in the fired core substrate by laser processing.

[0019] According to the present invention, it is possible to provide an interposer substrate and a core substrate that have low dielectric properties and high laser processability.

[0020] The interposer substrate and core substrate of the present invention are made of glass and SiO ２ In glass, cracks propagate when through-holes are formed by laser processing, making it difficult to form through-holes with a high yield. However, in the interposer substrate and core substrate of the present invention, the propagation of cracks is prevented by the use of SiO ２ Because the crystals are stopped, cracks are less likely to occur when forming through-holes, and through-holes can be formed with a high yield. In addition, it is possible to reduce the amount of debris generated during laser processing. Furthermore, SiO ２ Since crystals have low dielectric properties among ceramics, SiO ２ The dielectric properties of the interposer substrate and core substrate containing crystals are also likely to be reduced.

[0021] As ceramic powder, SiO ２ In addition to the crystals, other ceramic powders may be introduced. For example, one or more selected from β-tridymite, mullite, zirconia, and cordierite can be used. In particular, from the viewpoint of precisely adjusting the thermal expansion coefficient, it is preferable to introduce cordierite. SiO ２ By substituting a portion of the crystals with cordierite, it is possible to reduce only the thermal expansion coefficient without changing the glass composition, relative dielectric constant, or dielectric loss.

[0022] In the interposer substrate and the core substrate of the present invention, the glass has a composition of, in mol %, Li ２ O + Na ２ O+K ２ O 0.1 to 2% and, in molar ratio, Li ２ O / (Li ２ O + Na ２ O+K ２ O) 0.35-0.65, Na ２ O / (Li ２ O + Na ２ O+K ２ O) 0.25-0.55, K ２O / (Li ２ O + Na ２ O+K ２ O) is preferably 0.025 to 0.2. The reasons for limiting the content range of each component as described above are explained below. In this specification, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively.

[0023] Alkali metal oxides (Li ２ O, Na ２ O.K. ２ O) is a component that lowers the firing temperature but increases the dielectric properties. ２ O + Na ２ O+K ２ The O content is preferably 0.1 to 2%, 0.1 to 1.5%, 0.1 to 1%, 0.1 to less than 1%, 0.2 to 0.9%, and particularly preferably 0.3 to 0.8%. ２ The O content is preferably 0.1 to 1.2%, 0.1 to 1%, 0.1 to 0.7%, and particularly preferably 0.2 to 0.6%. ２ The O content is preferably 0.1 to 0.7%, 0.1 to 0.6%, 0.1 to 0.5%, and particularly preferably 0.2 to 0.4%. ２ The O content is preferably 0.01 to 0.3%, 0.01 to 0.2%, 0.01 to 0.1%, and particularly preferably 0.03 to 0.09%.

[0024] In order to effectively activate the alkali mixing effect and lower the dielectric properties, the molar ratio is ２ O / (Li ２ O + Na ２ O+K ２ O) is 0.35 to 0.65, Na ２ O / (Li ２ O + Na ２ O+K ２ O) is 0.25 to 0.55, K ２ O / (Li ２ O + Na ２ O+K ２ O) is preferably 0.025 to 0.2.

[0025] In addition to the above components, the glass composition may contain the following components.

[0026] SiO ２ is a component that acts as a glass network former. ２ The content of SiO is preferably 50 to 82%, 55 to 80%, and particularly preferably 60 to 78%. ２ If the content of SiO is too low, vitrification becomes difficult and it becomes difficult to obtain low dielectric properties. ２ If the content is too high, the firing temperature tends to be high.

[0027] B ２ O ３ is a component that suppresses devitrification of glass during melting. ２ O ３ The content of is preferably 17 to 30%, 18 to 30%, 19 to 30%, 20 to 30%, particularly preferably 21 to 29%. ２ O ３ If the content of B is too low, the glass is likely to devitrify. ２ O ３ If the content is too high, the firing temperature tends to be high.

[0028] In addition to the above components, Al may be used within a range that does not impair the dielectric properties. ２ O ３ Components such as MgO, CaO, SrO, BaO, and ZnO may be added in amounts of up to 3% each.

[0029] Glass having the above composition is likely to have a relative dielectric constant of 3.5 to 6, 3.6 to 5, particularly 3.7 to 4.5 at 16 GHz, and a dielectric dissipation factor of 0.003 or less, 0.0025 or less, particularly 0.002 or less at 16 GHz. If the relative dielectric constant and dielectric dissipation factor of the glass are high, the relative dielectric constant and dielectric dissipation factor of the interposer substrate will also be high, which will likely increase transmission signal loss and slow down signal processing speed.

[0030] In the interposer substrate and core substrate of the present invention, the glass content is 50 to 98 mass % and SiO ２ The crystal content is 2 to 50 mass %, the glass content is 50 to 95 mass %, and SiO ２ The crystal content is 5 to 50 mass %, the glass content is 50 to 90 mass %, and SiO ２The crystal content is 10 to 50 mass %, the glass content is 55 to 85 mass %, and SiO ２ The crystal content is 15 to 45 mass %, and in particular the glass content is 60 to 80 mass % and SiO ２ The content of the crystals is preferably 20 to 40 mass %. ２ If the amount of crystalline powder is too small, cracks are likely to occur when forming through-holes. ２ If the amount of crystalline powder is too large, it becomes difficult to densify the fired body, and the dielectric loss tangent tends to increase because the pores increase and electromagnetic waves are scattered.

[0031] SiO ２ Examples of the crystals include α-quartz, β-quartz, cristobalite, and tridymite. ２ The crystal is preferably alpha quartz, which has particularly low dielectric properties.

[0032] In the interposer substrate and core substrate of the present invention, glass, SiO ２ When containing crystals and cordierite, the glass content is 50 to 96 mass %, SiO ２ The crystal content is 2 to 48% by mass, the cordierite content is 2 to 48% by mass, and the glass content is 50 to 93% by mass, and SiO ２ It is preferable that the content of the crystals is 2 to 45% by mass, and the content of the cordierite is 5 to 48% by mass.

[0033] The interposer substrate and core substrate of the present invention preferably have a thermal expansion coefficient of 3 to 8 ppm / °C, particularly 3.6 to 6.5 ppm / °C. In this way, the thermal expansion coefficient of the interposer substrate and core substrate falls between the thermal expansion coefficients of the semiconductor element (approximately 3 ppm / °C) and the wiring substrate (10 to 15 ppm / °C). Therefore, when subjected to a heat cycle, distortion due to the difference in thermal expansion is less likely to occur.

[0034] In the interposer substrate and core substrate of the present invention, the relative dielectric constant at 16 GHz is preferably 3.5 to 6, 3.6 to 5, and particularly 3.7 to 4.5, and the dielectric loss tangent at 16 GHz is preferably 0.003 or less, 0.0025 or less, and particularly 0.002 or less. While there are no particular restrictions on the lower limit of the dielectric loss tangent, in practice, it is 0.0001 or more. When the relative dielectric constant or dielectric loss tangent is high, the loss of transmission signals tends to increase and the signal processing speed tends to slow down.

[0035] The core substrate is preferably a ceramic core substrate or a glass ceramic core substrate. As described above, this makes it possible to reduce cracks during the formation of through holes, resulting in high yields of through holes. It is also possible to reduce the amount of debris generated during laser processing. Here, "glass ceramic" refers to a material containing glass and ceramic, specifically a composite of glass and ceramic, or crystallized glass.

[0036] Next, a method for manufacturing the interposer substrate and core substrate of the present invention will be described below.

[0037] First, a glass powder having the above composition and SiO ２ A slurry is prepared by adding predetermined amounts of a binder, a plasticizer, and a solvent to the mixed powder of crystal powders. Suitable binders include polyvinyl butyral resin and methacrylic acid resin, suitable plasticizers include dibutyl phthalate, and suitable solvents include toluene and methyl ethyl ketone.

[0038] In addition, SiO ２ Average particle diameter D of crystalline powder ５０ is preferably 10 μm or less, 8 μm or less, and particularly preferably 5 μm or less. ２ Average particle diameter D of crystalline powder ５０ If the SiO2 content is too large, the effect of suppressing cracks when forming through-holes is reduced, and the surface smoothness of the interposer substrate is likely to decrease. ２ Average particle diameter D of crystalline powder ５０ If the lower limit is too small, the effect of suppressing crack generation when forming through holes will be small. ２Average particle diameter D of crystalline powder ５０ In the present invention, the average particle diameter D ５０ " is a value measured on a volume basis and refers to a value measured by a laser diffraction method.

[0039] The slurry is then formed into green sheets using a doctor blade method. The green sheets are then dried and cut to the required dimensions. Multiple green sheets are then stacked and integrated by thermocompression bonding. The stacked green sheets are then fired to obtain an interposer substrate and a core substrate. The firing temperature is preferably 1000°C or less, and more preferably 800 to 950°C.

[0040] Although an example of using a green sheet has been given as a method for manufacturing an interposer substrate, the present invention is not limited to this, and various methods generally used in the manufacture of ceramics can be applied, such as preparing a slurry dispersed in water or the like and using a slip casting method.

[0041] The slip casting method will be described in detail. First, 0.1 to 3.0 parts by mass of a water-soluble binder is added to 100 parts by mass of pure water, and then the mixture is mixed uniformly to obtain a solution. The water-soluble binder may be an acrylic, acrylic styrene, cellulose, polyvinyl alcohol, polyvinyl acetal, or other water-soluble binder. To 100 parts by mass of the obtained solution, glass powder and SiO ２ After adding 70 to 200 parts by mass of the mixed powder of crystal powders, the mixture is mixed in a mixer such as a planetary mill to obtain a slurry. The resulting slurry is poured into a plaster mold and left for 1 to 2 hours to allow the plaster mold to absorb water, resulting in a molded body. The resulting molded body is removed from the plaster mold, dried at 20 to 60°C for 5 to 24 hours, and then fired at 1000°C or less, particularly 800 to 950°C, to obtain an interposer substrate or core substrate.

[0042] If smoothness and flatness are required for the interposer substrate and core substrate, polishing is preferable. Smooth and flat interposer substrates and core substrates can be obtained by lapping with an alumina abrasive or polishing with a cerium oxide abrasive.

[0043] By using a laser processing machine such as a carbon dioxide laser, UV laser, or YAG laser on the fired interposer substrate and core substrate, through holes can be formed in the interposer substrate and core substrate. Electroless copper plating is then applied to ensure electrical continuity between the top and bottom surfaces.

[0044] Since the interposer substrate and core substrate of the present invention have high laser processability, through holes can be formed after firing. By forming through holes after firing, through holes with a desired diameter can be formed. However, if through holes are formed before firing, the hole diameter becomes small during firing, making it difficult to control the hole diameter and obtain the desired hole diameter.

[0045] Fine wiring for semiconductor packaging can be formed by forming a conductive material on an interposer substrate and a core substrate by sputtering, then forming a dry film resist and patterning it by exposure.

[0046] The present invention will be described below based on examples, but the present invention is not limited to these examples.

[0047] Tables 1 to 3 show examples of the present invention (samples Nos. 1 to 9, 11 to 13) and a comparative example (sample No. 10). In Tables 1 to 3, "Li + Na + K" means "Li ２ O + Na ２ O+K ２ O", and "Li / (Li+Na+K)", "Na / (Li+Na+K)", and "K / (Li+Na+K)" respectively mean "Li ２ O / (Li ２ O + Na ２ O+K ２ O) "Na ２ O / (Li ２ O + Na ２ O+K ２ O)" "K ２ O / (Li２ O + Na ２ O+K ２ O)).

[0048]

[0049]

[0050]

[0051] First, glass raw materials of various oxides were prepared and mixed uniformly to obtain the compositions shown in Tables 1 to 3, and then placed in a platinum crucible and melted at 1550 to 1650°C for 3 to 8 hours. The molten glass was then formed into a thin plate using a water-cooled roller. Next, the glass was roughly crushed, and then wet-pulverized in a ball mill with the addition of alcohol to obtain a glass having an average particle diameter D ５０ The glass powder was obtained by classifying the glass powder so that the particle size was 1.5 to 3 μm. The relative permittivity and dielectric loss tangent of the glass alone were measured at a measurement frequency of 16 GHz and a temperature of 25° C. using glass powder that was press-molded into a cylinder with a diameter of 13 mm and a height of 6.5 mm and then fired at 820 to 920° C. according to the both-ends shorted dielectric resonator method (JIS R1627).

[0052] Next, for samples No. 1 to 9 and 11 to 13, the amount of α-quartz powder (average particle diameter D ５０ : 2 μm), cordierite powder (average particle diameter D ５０ : 2 μm) were uniformly mixed to obtain a mixed powder.

[0053] Next, 15% by weight of polyvinyl butyral as a binder, 4% by weight of butyl benzyl phthalate as a plasticizer, and 30% by weight of toluene as a solvent were added to the mixed powder (glass powder for Sample No. 10) to prepare a slurry. The slurry was then formed into green sheets using a doctor blade method, dried, and cut to a specified size. After that, several sheets were stacked and integrated by thermocompression bonding. The laminated green sheets were then fired to obtain interposer substrates and core substrates.

[0054] The firing temperature, dielectric properties, thermal expansion coefficient, and laser processability of each sample thus obtained were evaluated. The results are shown in Tables 1 to 3.

[0055] The firing temperature is the lowest temperature at which ink is applied to sintered bodies fired at various temperatures and then wiped off, leaving no ink behind (i.e., densely sintered).

[0056] The relative permittivity and dielectric loss tangent were measured at a measurement frequency of 16 GHz and a temperature of 25°C based on the both-ends shorted dielectric resonator method (JIS R1627) using a mixture of powders that had been press-molded into a cylinder with a diameter of 13 mm and a height of 6.5 mm and then fired at 820 to 920°C.

[0057] The thermal expansion coefficient was measured in the temperature range of 30 to 380°C using a thermomechanical analyzer.

[0058] The laser processability was evaluated as follows: ２ Using a laser processing machine GTW4, through holes with a diameter of 100 μm were formed at a pitch of 200 μm on the surface of the measurement sample. Samples for which no cracks occurred were evaluated as "○", and samples for which cracks occurred were evaluated as "×". The laser processing conditions were a wavelength of 9.3 μm, a pulse width of 1 to 5 μs, and percussion processing using multiple pulses.

[0059] As is clear from Tables 1 to 3, the example samples Nos. 1 to 9 and 11 to 13 had a relative dielectric constant of 3.7 to 3.9 and a low dielectric loss tangent of 0.0011 to 0.0013. They also had excellent laser processability. On the other hand, sample No. 10, which did not contain α-quartz, had poor laser processability.

[0060] To 100 parts by mass of pure water, 0.5 parts by mass of an acrylic water-soluble binder was added, and the mixture was mixed uniformly to obtain a solution. To 100 parts by mass of the obtained solution, 130 parts by mass of the above mixed powder (Samples No. 1 to 9, 11 to 13) was added, and the mixture was mixed using a planetary mill to obtain a slurry. The obtained slurry was poured into a plaster mold and left for 1 hour to allow the plaster mold to absorb water, thereby obtaining a molded body. The obtained molded body was removed from the plaster mold, dried at 40°C for 24 hours, and then fired at 850°C to obtain an interposer substrate and a core substrate.

[0061] The firing temperature, dielectric properties, thermal expansion coefficient and laser processability of each sample thus obtained were evaluated, and the results were similar to those of Example 1.

Claims

1. Glass and SiO ２ An interposer substrate comprising crystals.

2. The glass has a composition, in mol%, of Li ２ O+Na ２ O+K ２ O 0.1 to 2% and, in molar ratio, Li ２ O / (Li ２ O+Na ２ O+K ２ O) 0.35-0.65, Na ２ O / (Li ２ O+Na ２ O+K ２ O) 0.25-0.55, K ２ O / (Li ２ O+Na ２ O+K ２ 2. The interposer substrate according to claim 1, wherein the thickness of the interposer substrate is 0.025 to 0.

2.

3. Glass content is 50-98% by mass, SiO ２ 3. The interposer substrate according to claim 1, wherein the crystal content is 2 to 50 mass %.

4. Glass content is 50-96% by mass, SiO ２ 3. The interposer substrate according to claim 1, wherein the crystal content is 2 to 48 mass %, and the cordierite content is 2 to 48 mass %.

5. An interposer substrate according to claim 1 or 2, characterized in that the thermal expansion coefficient is 3 to 8 ppm / °C.

6. An interposer substrate according to claim 1 or 2, characterized in that the relative dielectric constant at 16 GHz is 3.5 to 6.

7. An interposer substrate according to claim 1 or 2, characterized in that the dielectric tangent at 16 GHz is 0.003 or less.

8. Glass and SiO ２ A core substrate comprising a crystal.

9. Glass powder and SiO ２ A method for producing an interposer substrate, comprising slip casting a slurry containing a mixed powder of crystal powder to obtain a molded body, and then drying and firing the molded body to obtain an interposer substrate.

10. A method for manufacturing an interposer substrate according to claim 1, characterized in that through holes are formed in the interposer substrate according to claim 1 after firing by laser processing.

11. Glass powder and SiO ２ A method for producing a core substrate, comprising slip casting a slurry containing a mixed powder of crystal powders to obtain a molded body, and then drying and firing the molded body to obtain a core substrate.

12. A method for producing a core substrate, comprising the steps of: forming through holes in the core substrate according to claim 8 after firing by laser processing.