JP4423025B2 - Multilayer substrate and manufacturing method thereof - Google Patents

Description

  The present invention relates to a method for producing a multilayer board suitable for a circuit board, and in particular, is a multilayer board mounted as a component for high-frequency applications in communication equipment, electronic equipment, etc., and has different shrinkage curves (behavior) during firing. The present invention relates to a method for manufacturing a multilayer substrate excellent in dimensional accuracy in which insulating sheets are integrally fired to suppress firing shrinkage in the XY directions.

  Conventionally, a multilayer substrate using ceramics as an insulating substrate has been used, but in recent years, addition of various functions to the multilayer substrate has been demanded, and a multilayer substrate combining different ceramics has been proposed. For example, in order to reinforce a low-strength insulating layer with a high-strength insulating layer, or to incorporate a high-capacitance capacitor in a multilayer substrate, a high-permittivity insulating layer in a low-dielectric constant insulating layer, etc. A multilayer substrate in which is laminated is known.

  In such a multilayer substrate, in order to prevent ceramic cracks and delamination (delamination), the characteristics of the insulating layer material are selected and controlled so that the firing shrinkage rate and the thermal expansion coefficient coincide between different insulating layers. It is usually done.

  However, in recent years, in order to reduce the cost of the multilayer substrate and improve the dimensional accuracy of the electrodes formed on the multilayer substrate, it is required to reduce the shrinkage rate of the multilayer substrate in the XY direction during firing. Therefore, this requirement cannot be achieved by the conventional multilayer substrate.

In order to satisfy these requirements, in recent years, firing shrinkage in the thickness direction has been increased by firing a laminated molded body of unfired insulating green sheets while applying pressure through an Al ₂ O ₃ sintered plate. Developed a method to remove the unfired ceramic layer after it is constrained by the unfired ceramic layer that does not sinter at the firing temperature of the laminated body and shrinks only in the thickness direction on the surface of the laminated molded body (For example, refer to Patent Document 1).

However, the former pressure firing method requires an Al ₂ O ₃ sintered plate without warping and a special pressure means. Further, the method of restraining by the unfired ceramic layer has a problem that the number of manufacturing steps increases because the unfired ceramic layer needs to be removed after the firing is completed.

Therefore, it has been proposed to suppress dimensional changes due to shrinkage of firing by laminating two types of ceramic molded bodies having different firing shrinkage start temperatures and firing them simultaneously (for example, see Patent Document 2).
Japanese Patent No. 2554415 Japanese Patent Laid-Open No. 2002-261443

  However, in the method for manufacturing a circuit board described in Patent Document 2, when two types of ceramic molded bodies having different firing shrinkage start temperatures are stacked and fired simultaneously, the insulating layer whose firing shrinkage start temperature is high starts to shrink. At that time, the dimensional change of the circuit board can be suppressed by setting the insulating layer whose firing shrinkage starting temperature is lower than 90% of the final firing volume shrinkage, but the dimensional change of the circuit board can be suppressed. Since only the shrinkage start temperature is controlled, there is a problem in that the behavior of shrinkage suppression is large and the shrinkage rate is not sufficiently small.

Accordingly, the present invention is excellent in dimensional accuracy, close to the planar direction of shrinkage 0, it is an object to provide a small multi-layer substrate and a manufacturing method thereof variation in the shrinkage.

This onset Ming,
(A ) A step of producing a first slip containing at least a first insulating inorganic material and a photocurable resin, and a second slip containing a second insulating inorganic material and a photocurable resin (b) a supporting substrate above, the first slip and / or the second slip coating, dried, exposed, after curing, and peeling from the supporting substrate, a step of preparing a first insulating sheet and / or the second insulation sheet (c) before Symbol first insulating sheet and the process for producing a molded laminate said second insulating sheets each stacked step (d) for firing the molded laminate
In the manufacturing method of the multilayer substrate comprising:
The first insulating sheet and the second insulation sheet includes a different crystallized glass powder, the crystallization temperature of the crystallized glass powder contained in the first dielectric sheet, the crystallized glass powder contained in the second insulating sheet it is characterized in that below the softening point.

  It is preferable that an inner conductor pattern having a film thickness of 20 μm or more is formed between the first insulating sheet and the second insulating sheet in the laminated molded body of the insulating sheets.

  The support substrate is preferably transparent.

The first insulating sheet and the second insulation sheet, it is preferable that each include a crystallized glass powder 30% by weight or more.

The first insulating sheet and the crystallized glass powder contained in the second insulating sheet, Diopusai de by firing, Hardy strike Nai DOO, Serushia down, Kojerai DOO, Anosai DOO, Ganai DOO, Wiremai DOO, spinel Le, Murai DOO is preferably a glass powder for forming a crystal composed of at least one of false Terai preparative及 beauty Suanai bets.

Multilayer substrate of the present invention is preferably composed of a multilayer structure of insulating layers each containing a different crystallized glass obtained by the manufacturing method of the multilayer substrate, crystals of crystallized glass contained in the first insulating layer of said insulating layer The crystallization temperature is lower than the softening point of the crystallized glass contained in the second insulating layer.

It is preferred thermal expansion coefficient difference between the first insulating layer and the second insulating layer is 2 × 10 -6 ^/ ° C. or less.

Crystallized glass contained in the first insulating layer and the second insulating layer, diopside, hardystonite, celsian, cordierite, anorthite, gahnite, willemite, spinel, mullite, forsterite, scan Anai bets Of these, crystals comprising at least one kind are preferred.

The method of manufacturing a multilayer substrate of the present invention, by integrally firing a different first insulating sheet and the second insulation sheet of firing shrinkage behavior, the second insulating sheet when one of the first insulating sheet starts to shrink Since the shrinkage in the XY direction is suppressed, the first insulating sheet completes the shrinkage, and the sintering of the second insulating sheet is started during crystallization, the shrinkage of the second insulating sheet in the XY direction As a result of being suppressed by the first insulating sheet, it is possible to stably exhibit the mutual shrinkage suppression effect, and to suppress firing shrinkage in the XY directions before and after sintering as the entire multilayer substrate. Therefore, to suppress the variation of firing shrinkage and the shrinkage rate can be brought close to zero, it is possible to provide a high dimensional accuracy multilayer substrate.

In particular, since the crystallization temperature of the glass contained in the first insulating layer is lower than the softening point of the glass contained in the second insulating layer, the dimensional accuracy is excellent, and the shrinkage rate in the plane direction is close to 0. A multilayer substrate with small variation in shrinkage rate can be manufactured.

  When an internal conductor pattern having a film thickness of 20 μm or more is formed between the first insulating sheet and the second insulating sheet in the laminated molded body of the insulating sheet, the conductor resistance becomes lower, and a high-performance element It becomes easy to incorporate.

  When the support substrate is transparent, exposure processing can be performed by irradiating light from the back surface of the support substrate, and an insulating sheet having a certain thickness can be cured from the support substrate.

The insulating sheet first and the second insulation sheet, if each containing crystallized glass powder 30% by weight or more, it is possible to obtain a more stable sinterability and adhesion.

The first insulating sheet and the crystallized glass powder contained in the second insulating sheet, Diopusai de by firing, Hardy strike Nai DOO, Serushia down, Kojerai DOO, Anosai DOO, Ganai DOO, Wiremai DOO, spinel Le, Murai DOO If a glass powder for forming a crystal composed of at least one of false Terai preparative及 beauty Suanai DOO, can further improve the dielectric properties or strength.

Multilayer substrate of the present invention is preferably composed of a multilayer structure of insulating layers each containing a different crystallized glass obtained by the above manufacturing method, the crystallization temperature of the crystallized glass contained in the first insulating layer of the insulating layer , which is characterized in that less than the softening point of the glass contained in the second insulating layer, excellent in dimensional accuracy, close to the planar direction of shrinkage 0, the multilayer substrate variations in the shrinkage rate is small Can be provided.

In particular, the difference in coefficient of thermal expansion of the first insulating layer and the second insulating layer, if it is 2 × 10 -6 ^/ ° C. or less, preferably in terms of suppressing the occurrence of cracking and delamination in the multilayer substrate.

Crystallized glass contained in the first insulating layer and the second insulating layer, diopside, hardystonite, celsian, cordierite, anorthite, gahnite, willemite, spinel, mullite, forsterite, scan Anai bets In the case of a crystal composed of at least one of them, the dielectric properties or strength can be further improved.

  FIG. 1 shows a schematic cross-sectional view of an embodiment of a multilayer substrate according to the present invention.

  According to FIG. 1, the multilayer substrate 1 includes a ceramic insulating substrate on which an insulating layer 2 is laminated, a wiring conductor layer 3, a chip component 4, and a via hole conductor 5.

  The first insulating layer and the second insulating layer are formed of insulating sheets having different shrinkage start temperatures, and at least one layer of the insulating sheet 2, for example, a crystallized glass powder contained in the first insulating sheet. It is important that the crystallization temperature is lower than the softening point of the crystallized glass powder contained in another insulating sheet, for example, the second insulating sheet. For example, it is possible to adopt a structure in which insulating sheets having different shrinkage start temperatures are alternately arranged for each layer. By combining two types of insulating sheets having such a relationship, the shrinkage behavior can be remarkably controlled.

  Here, the thermal characteristics of the crystallized glass contained in the insulating sheet 2 will be described. The crystallization temperature of the crystallized glass contained in the insulating sheet 1 that starts shrinking from a low temperature is lower than the softening point of the crystallized glass contained in the insulating sheet 2 that starts shrinking at a higher temperature. When the shrinkage starts, the firing shrinkage of the insulating sheet A is almost finished (90% or more of the final firing volume shrinkage amount), and it is possible to suppress the mutual shrinkage in the XY directions. In particular, in order to more effectively suppress shrinkage in the X-Y direction, the difference between the softening point of one glass and the crystallization temperature of the other glass is desirably 10 ° C. or more.

  It is preferable that an inner conductor pattern having a film thickness of 20 μm or more is formed between the first insulating sheet and the second insulating sheet in the laminated molded body of the insulating sheets. As described above, when the internal conductor pattern is formed, the resistance of the conductor can be reduced, so that it becomes easy to incorporate a high-performance element such as a band-pass filter having a low insertion loss in the substrate.

Moreover, it is desirable that the difference in thermal expansion coefficient between the insulating sheet A and the insulating sheet B after firing is 2 × 10 ⁻⁶ / ° C. or less. This is because when the difference in thermal expansion coefficient exceeds 2 × 10 ⁻⁶ / ° C., a difference in thermal shrinkage occurs during cooling from the maximum firing temperature, and cracks and delaminations occur at the interface between the insulating sheet and the insulating sheet of the different material. This is because. In particular, the difference in thermal expansion coefficient is preferably 1 × 10 ⁻⁶ / ° C. or less from the viewpoint of cracks and delamination.

  According to the present invention, it is preferable from the viewpoint of sinterability that each of the two types of insulating sheets is composed of 30 to 100 parts by weight of crystallized glass powder and 0 to 70 parts by weight of ceramic powder.

Examples of the ceramic powder include Al ₂ O ₃ , SiO ₂ , MgTiO ₃ , CaZrO ₃ , CaTiO ₃ , Mg ₂ SiO ₄ , BaTi ₄ O ₉ , ZrTiO ₄ , SrTiO ₃ , BaTiO ₃ , TiO ₂ , AlN, and SiN. It is done.

  The crystals formed after firing two types of unfired insulating sheets with different firing shrinkage temperatures are diopside, hardistonite, celsian, cordierite, anorthite, garnite, willemite, spinel, mullite, and forsterite. From the viewpoints of the shrinkage-suppressing effect in the XY direction, the bending strength of the substrate, and the dielectric loss, it is preferable that the amount of residual glass is 10% by volume or less.

  The insulating sheet used in the multilayer substrate of the present invention can be fired at 1000 ° C. or lower, can be formed using a low-resistance conductor such as Cu, Ag, Al as the conductor layer, and has a low dielectric constant. The rate can be increased and is suitable for high-speed transmission. In addition, by controlling various compositions within the above range, the firing shrinkage behavior can be easily controlled and changed.

  Next, the manufacturing method of the multilayer board | substrate of this invention is demonstrated concretely.

First, the raw material powder used for a 1st insulating sheet and a 2nd insulating sheet is prepared. Prepare crystallized glass powder and ceramic powder. The crystallized glass powder, Diopusai de by firing, Hardy strike Nai DOO, Serushia down, Kojerai DOO, Anosai DOO, Ganai DOO, Wiremai DOO, spinel Le, mullite DOO, false Terai preparative及 beauty Suanai least one of bets glass powder der Rukoto forming a of crystalline are preferable in view of dielectric properties or strength.

Also, as ceramic powder, Al ₂ O ₃ powder, SiO ₂ powder, MgTiO ₃ powder, CaZrO ₃ powder, CaTiO ₃ powder, Mg ₂ SiO ₄ powder, BaTi ₄ O ₉ powder, ZrTiO ₄ powder, SrTiO ₃ powder, BaTiO ₃ From the viewpoint of dielectric properties or strength, at least one of powder, TiO ₂ powder, AlN powder, and Si ₃ N ₄ powder is preferable.

Here, it is important that the crystallization temperature of the crystallized glass powder contained in the first insulating sheet is lower than the softening point of the crystallized glass powder contained in the second insulating sheet. With the combination of such crystallized glass, high dimensional accuracy, close to the planar direction of shrinkage 0, it is possible to provide a multi-layer substrate variations in the shrinkage rate is small.

That is, since the crystallization temperature of the crystallized glass contained in the first insulating sheet that starts shrinking from a low temperature is lower than the softening point of the crystallized glass contained in the second insulating sheet that starts shrinking at a higher temperature, the second When the insulating sheet starts to shrink, the firing shrinkage of the first insulating sheet is almost finished (97% or more, particularly 98% or more, more preferably 99% or more of the final firing volume shrinkage), and the XY directions of each other It is possible to suppress the contraction of each other. Especially, in order to each other more effectively suppress the shrinkage of the X-Y direction, the difference between the crystallization temperature of the softening point and the other of the crystallized glass of one of the crystallized glass is desirably more than 10 ° C..

In addition, according to the present invention, it is important to include the following steps. First, it includes a step of producing a first slip containing at least a first insulating inorganic material and a photocurable resin, and a second slip containing a second insulating inorganic material and a photocurable resin. you. As the insulating inorganic material, the above ceramics can be used.

Here, the composition of the crystallized glass and the ceramics of the first slip and the second slip is such that the first and second insulating sheets each have a crystallized glass powder of 30% by mass or more, particularly 40 to 90% by mass, Setting so as to include 50 to 80% by mass is preferable in terms of enhancing the sinterability.

A first slip and a second slip are produced using the above powder. These slips consist of an insulating inorganic material composed of a predetermined crystallized glass powder and ceramic powder represented by the above powder, a photocurable resin that easily volatilizes during firing, an organic solvent, and plastic as required. A slip can be created by mixing with the agent.

Next , on the support substrate, the first slip and / or the second slip is applied, dried , exposed and cured, and then peeled off from the support substrate , and the first insulating sheet and / or the second insulating sheet is removed. It comprising the step of making. Using the above slip, perform tape formed by such a lip coater method or doctor blade method, on a transparent supporting substrate, coated with two slip, dried, and cut as desired, then an exposure, curing Then, the first insulating sheet and the second insulating sheet are peeled from the support substrate .

The support substrate is preferably transparent. By being transparent, it can be determined promptly by using an exposure process from the rear surface of the supporting substrate is irradiated with light.
Prior to slip coating, the via hole conductor, surface conductor layer, internal conductor layer, and back conductor layer are coated on the transparent support substrate using a conductive paste in advance by screen printing, on-contact printing, inkjet printing, or the like. It can be formed.

Next, it includes a step of preparing a molded laminate the first insulating sheet and the second insulation sheet obtained in the preceding step respectively by stacking a plurality. The first insulation sheet and the second insulation sheet obtained it is possible to produce a laminated article by laminating in accordance with a predetermined stacking sequence.

  Here, it is preferable that an internal conductor pattern having a film thickness of 20 μm or more is formed between the first insulating sheet and the second insulating sheet in the laminated molded body. Thus, when the internal conductor pattern having a thickness of 20 μm or more is formed, the conductor resistance can be further reduced.

Finally, it includes a step of firing the obtained laminated molded body. Firing In is also possible in multi-stage calcination to be temporarily held at a temperature between the crystallization temperature of the crystallized glass contained in the low-temperature side at a shrinkage start temperature and its insulating sheet insulating sheet shrinkage begins, ordinary single By performing simultaneous firing even at one keep temperature, a substrate with high dimensional accuracy can be manufactured in which firing shrinkage in the XY direction is suppressed and firing shrinkage in the Z direction.

  Two types of ceramics with different firing shrinkage start temperatures, for example, not only differ in sintering shrinkage behavior, but also depending on the purpose, relative permittivity, bending strength, dielectric loss, thermal conductivity, bulk density, temperature coefficient Other characteristics such as may be the same or different.

  In addition, as a laminated form of two types of ceramic insulating sheets A-B having different firing shrinkage behavior, as an arrangement example, ABBBBBBA, ABABABA, AAABAAA, AABBBAA, AABABAA, AABBAAA, ABAAAAA, ABAAABA, ABBABBA, ABABAAA, ABABAAA, ABBAAA ABBBBAA may be used, and A and B may be reversed.

First, the 1st insulating sheet and the 2nd insulating sheet were produced. That is, crystallized glass powder shown in Table 1, ceramic powder, photocurable monomers as polyoxyethylated trimethylol and propane triacrylate, alkyl methacrylate as an organic binder, and ethyl carbitol acetate as an organic solvent. Were mixed and kneaded by a ball mill to produce first and second slips, respectively.

  Next, in order to produce a conductor pattern, a conductive paste containing Ag powder was printed on a predetermined position of a transparent carrier sheet and dried. In addition, as a carrier sheet, the glass plate, PET film, etc. were used and removed before the baking process.

On the carrier sheet on which the conductor pattern is formed, coated and dried by a lip coater method, an exposure process further, development, washing, drying processes performed, the first insulating sheet and the second insulation electrode pattern is formed A sheet was obtained.

In addition, the exposure process exposed using the ultrahigh pressure mercury lamp (10 mW / cm < ² >) as a light source from the back side of a support substrate. As a result, the region where the wiring pattern was formed was shielded from light, the photopolymerization reaction of the photocurable monomer did not occur, and the photopolymerization reaction occurred in other regions. Here, a site where the photopolymerization reaction has occurred is referred to as an insolubilized portion, and a site where no photopolymerization reaction has occurred is referred to as a solubilized portion.

In the development process, the solubilized portions of the first insulating sheet and the second insulating sheet are removed with a developer, spray development is performed using a triethanolamine aqueous solution as a developer, and then unnecessary waste generated by the development is removed. It was completely removed by washing and drying processes.

  The firing shrinkage start temperature and shrinkage end temperature of each insulating sheet are shown in Table 1. In these measurements, a green compact is separately formed by adding wax to the composition of each insulating sheet shown in Table 1 and pressing it at 100 MPa. The shrinkage start temperature S, shrinkage end temperature E, and thermal expansion coefficient at room temperature to 900 ° C. of each ceramic were evaluated in the temperature range of room temperature to 1000 ° C. by mechanical analysis.

  After the first and second insulating sheets were peeled from the carrier sheet, a laminated molded body was formed by alternately stacking and pressing together while aligning the five first and second insulating sheets. In addition, the pressure bonding was performed while applying a temperature higher than the glass transition point of the organic binder in the insulating sheet. Note that only the lowermost surface and the uppermost surface were laminated and pressure-bonded without being peeled off from the carrier film, and then the carrier film was peeled off to form a laminated molded body.

  The obtained laminated molded body was subjected to a binder removal treatment at 400 ° C. in the atmosphere, and further fired at 910 ° C. to produce a multilayer substrate as shown in FIG. Each insulating sheet had a thickness of 0.02 mm, and the multilayer substrate had a length of 10 mm, a width of 10 mm, and a thickness of 0.6 mm.

  Next, the shrinkage ratio of the multilayer substrate in the XY direction was measured by measuring the length between predetermined points on the multilayer molded body before firing and the multilayer substrate after firing. The shrinkage rate is 10 samples for each sample number, each shrinkage rate is measured, and the average value is taken as the shrinkage rate, and the difference between the maximum shrinkage rate and the minimum shrinkage rate among the 10 samples. Was evaluated as shrinkage variation.

  Further, the surface of the multilayer substrate was polished and observed with an optical microscope to examine the presence or absence of cracks and delamination in the multilayer substrate, and this was evaluated as a defect.

The crystallization temperature T _c of the crystallized glass contained in the first insulating layer and the softening point T _g of the crystallized glass contained in the second insulating layer are 10 ° C./min by DTA (suggested thermal analysis). It was determined from the curve obtained by raising the temperature. The results are shown in Tables 1 and 2.

Sample No. of the present invention. The multilayer substrates 1 to 4 and 7 to 10 have a shrinkage rate as small as 4% or less, and the shrinkage variation is 0.3% or less, and defects such as cracks and delamination were not observed in the multilayer substrate. Thus, the multilayer substrate of the present invention is excellent in dimensional accuracy, the planar direction of shrinkage is close to 0, were those variations in shrinkage rate is small.

  On the other hand, the crystallization temperature of the crystallized glass contained in the first insulating layer is higher than the softening point of the crystallized glass contained in the second insulating layer. 5 and 6 had a shrinkage ratio of 8.5% or more and a shrinkage variation of 0.7% or more.

The schematic sectional drawing which shows an example of the ceramic multilayer substrate of this invention is shown.

Explanation of symbols

1 ... multilayer substrate 2 ... insulating sheet 1 or 2
3... Wiring conductor layer 4... Chip component 5... Via hole conductor

Claims (8)

(A ) A step of producing a first slip containing at least a first insulating inorganic material and a photocurable resin, and a second slip containing a second insulating inorganic material and a photocurable resin (b) a supporting substrate above, the first slip and / or the second slip coating, dried, exposed, after curing, and peeling from the supporting substrate, a step of preparing a first insulating sheet and / or the second insulation sheet (c) before Symbol first insulating sheet and the process for producing a molded laminate said second insulating sheets each stacked step (d) for firing the molded laminate
In the manufacturing method of the multilayer substrate comprising:
The first insulating sheet and the second insulation sheet includes a different crystallized glass powder, the crystallization temperature of the crystallized glass powder contained in the first dielectric sheet, the crystallized glass powder contained in the second insulating sheet A method for producing a multilayer substrate, characterized by being lower than the softening point of the substrate. 2. The multilayer substrate according to claim 1 , wherein an inner conductor pattern having a thickness of 20 μm or more is formed between the first insulating sheet and the second insulating sheet in the multilayer molded body. Production method. Method of manufacturing a multilayer substrate according to claim 1 or 2, wherein the supporting substrate is transparent. The first insulating sheet and the second insulation sheet, a method for manufacturing a multilayer substrate according to claim 1, characterized in that each include the crystallized glass powder more than 30 mass%. The first said crystallized glass powder contained in the insulating sheet and the second insulation sheet, Diopusai de by firing, Hardy strike Nai DOO, Serushia down, Kojerai DOO, Anosai DOO, Ganai DOO, Wiremai DOO, spinel Le, Murai preparative method of manufacturing a multilayer substrate according to claim 1, characterized in that the glass powder for forming a crystal composed of at least one of false Terai preparative及 beauty Suanai bets. A crystallized glass comprising a laminate of insulating layers each including different crystallized glasses obtained by the method for producing a multilayer substrate according to any one of claims 1 to 5 , wherein the crystallized glass is included in the first insulating layer among the insulating layers. A multilayer substrate characterized in that the crystallization temperature is lower than the softening point of the crystallized glass contained in the second insulating layer. The multi-layer substrate of claim 6, wherein the thermal expansion coefficient difference between the first insulating layer and the second insulating layer is 2 × 10 -6 ^/ ° C. or less. The first said crystallized glass contained in the dielectric layer and the second insulating layer, diopside, hardystonite, celsian, cordierite, anorthite, gahnite, willemite, spinel, mullite, forsterite, scan Anai DOO The multilayer substrate according to any one of claims 6 to 7, wherein the multilayer substrate is a crystal composed of at least one of them.

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