JP2008109018A - Wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board having high dimensional accuracy and proper resistance against chemicals. <P>SOLUTION: In the wiring board made of glass ceramics and having at least two kinds of insulating layers that have different baking shrinkage start temperatures and a wiring layer, where the insulating layers to be baked and shrunk at a low temperature are first insulating layers 11, 23 and the insulating layers to be baked and shrunk at a temperature higher than that of the first insulating layers 11, 23 are second insulating layers 13-21 from among the insulating layers, the glass of each of the first insulating layer 11, 23 contains F, the F content in the first insulating layers 11, 23 is 1-6 mass%, and the total amount of B<SB>2</SB>O<SB>3</SB>and an alkali metal oxide of the first insulating layers 11, 23 is 10 mass% or smaller. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wiring board, and more particularly to a multilayer wiring board that requires high dimensional accuracy.

  Conventionally, a wiring substrate using a so-called glass ceramic as an insulating layer using Au, Ag, and Cu having a low resistance and a low melting point as a wiring layer has been used. Further, in recent years, various functions are required to be added to a wiring board, and it has been proposed to combine insulating layers having different compositions in a wiring board using glass ceramics as an insulating layer.

  For example, a wiring board in which a high dielectric constant insulating layer or the like is laminated in a low dielectric constant insulating layer in order to incorporate a capacitor having a high capacitance value in the wiring board has been proposed (for example, Patent Documents). 1).

  In a wiring board in which different types of materials are laminated, cracks and delamination may occur between insulating layers due to mismatch in firing shrinkage and thermal expansion coefficients between insulating layers having different compositions and characteristics. Therefore, the characteristics of the insulating layer are selected and controlled so that the shrinkage rate and thermal expansion coefficient of each insulating layer material match as much as possible.

  In recent years, the difference in firing shrinkage between insulating layers has been actively utilized to reduce the shrinkage of the wiring board in the plane direction during firing (the direction perpendicular to the stacking direction). It has also been proposed to increase the dimensional accuracy of the electrodes formed.

  That is, by laminating insulating layers with different firing shrinkage start temperatures and co-firing, the two types of insulating layers are shrunk at different temperatures, so that the insulating layers limit the shrinkage in the plane direction to each other. A method has been proposed in which the shrinkage rate in the planar direction is reduced to increase the dimensional accuracy (see, for example, Patent Document 2).

At this time, since the insulating layer having a low firing shrinkage temperature is required to complete the firing shrinkage when the insulating layer having a high firing shrinkage temperature starts shrinking, the glass contained in the insulating layer is It is necessary to add a large amount of B ₂ O ₃ or an alkali metal oxide to lower the glass softening point so that the glass can be softened and flowed at a lower temperature (see, for example, Patent Document 3). .
JP-A-8-228078 JP 2001-15875 A JP 2003-246644 A

However, when a large amount of B ₂ O ₃ is added to lower the firing shrinkage start temperature, the glass becomes difficult to crystallize during firing, and the state of softening and flowing in the firing temperature range is continued, resulting in insufficient rigidity. There is a possibility that the plane shrinkage of the insulating layer having a high firing shrinkage start temperature cannot be sufficiently suppressed, or that the substrate is warped and deformed. In addition, when a large amount of alkali metal oxide is added to lower the firing shrinkage start temperature, crystallization during firing is promoted and rigidity in the firing temperature range is improved, but the insulation resistance value is lowered. There was a problem.

Accordingly, an object of the present invention is to provide a wiring board with good insulation, minimizing the addition of B ₂ O ₃ and alkali metal oxide, having high dimensional accuracy, and small deformation such as warpage. Is.

  The wiring board of the present invention is made of glass ceramics and includes at least two types of insulating layers having different firing shrinkage start temperatures and a wiring layer, and among the insulating layers, the insulating layer that is fired and shrunk on a low temperature side. Is the first insulating layer, and the second insulating layer is an insulating layer that is baked and shrunk on a higher temperature side than the first insulating layer, the glass of the first insulating layer contains F, and The content of F in the first insulating layer is 1 to 6% by mass, and the total amount of B 2 O 3 and alkali metal oxide in the first insulating layer is 10% by mass or less.

In the wiring board of the present invention, the total amount of B ₂ O ₃ and the alkali metal oxide in the second insulating layer is smaller than that in the first insulating layer, and the glass F in the second insulating layer is contained. Desirably, the amount is less than the first insulating layer.

In the wiring board of the present invention, the first insulating layer may contain at least one selected from the group consisting of ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO _{2 in} a total amount of 1 to 5% by mass. It is desirable to contain.

In the wiring board of the present invention, the second insulating layer contains at least one selected from the group consisting of ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO ₂ , and the total amount is the first. It is desirable that the number be less than that of the insulating layer.

According to the wiring substrate of the present invention, in the first insulating layer that is fired and contracted on the low temperature side, the total amount of B2O3 and the alkali metal oxide is set to 10% or less, whereby the firing temperature range of the first insulating layer Therefore, it is possible to minimize the decrease in the crystallization rate of the glass phase due to the addition of B ₂ O ₃ and the decrease in the insulation resistance value due to the addition of the alkali metal oxide. In addition, by containing 1 to 6% by mass of F, the firing shrinkage start temperature of the first insulating layer is effectively lowered, and by promoting crystallization, rigidity in the firing temperature range is increased. Therefore, when the second insulating layer starts firing shrinkage, the shrinkage in the plane direction can be effectively suppressed, and the wiring board having excellent dimensional accuracy is obtained. Further, resistance to deformation such as warping of the wiring board is increased.

According to the wiring board of the present invention, the second insulating layer has a crystal phase, and the total amount of B2O3 and alkali metal oxide of the second insulating layer is greater than that of the first insulating layer. It is desirable that the content of F in the second insulating layer is less than that in the first insulating layer. Thus, also in the second insulating layer, B ₂ O ₃ and alkali metal reduction of the crystallization rate by addition of the oxide and the reduction in the insulation resistance can be minimized. Further, by containing F, crystallization can be promoted, the strength of the second insulating layer can be improved together with the first insulating layer, and the strength of the entire substrate can be improved. Furthermore, since the content of B ₂ O ₃ , alkali metal oxide, and F contained in the second insulating layer is less than that of the first insulating layer, these firings are started during firing. It can suppress that the component which reduces temperature moves to a 1st insulating layer, and generate | occur | produces a various malfunction.

Moreover, according to the wiring board of the present invention, the first insulating layer contains at least one selected from the group consisting of ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO _{2 in} a total amount of 1 to 5 It is more desirable to contain by mass. ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO ₂ are effective in promoting crystallization of the glass and lowering the shrinkage start temperature. By promoting the crystallization, the rigidity in the firing temperature range can be increased, so that the shrinkage in the planar direction can be more effectively suppressed when the second insulating layer starts firing shrinkage. In addition, resistance to deformation such as warpage of the substrate is further increased. Moreover, since the ratio of the crystalline after baking becomes large, the intensity | strength of a 1st insulating layer can be improved more by containing glass. Furthermore, since the shrinkage start temperature is lowered, it becomes easier to start shrinkage at a temperature lower than the shrinkage start temperature of the second insulating layer.

According to the wiring board of the present invention, the second insulating layer contains at least one selected from the group consisting of ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO ₂ , and its total amount Is less than the first insulating layer. As described above, ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO ₂ have the effect of promoting the crystallization of glass and lowering the shrinkage start temperature. The strength of the second insulating layer can be improved together with the first insulating layer, and the strength of the entire substrate can be improved. In particular, when the total amount of ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO ₂ is less than that of the first insulating layer, the firing shrinkage start temperature of the second insulating layer is reduced to the first insulating layer. It becomes easy to make it higher.

  The present invention will be described with reference to the accompanying drawings.

  For example, as shown in FIG. 1, a wiring substrate 100 of the present invention includes an insulating substrate 1 made of an insulating layer made of a plurality of glass ceramics, a surface wiring layer 3 formed on the front and back surfaces of the insulating substrate 1, and an insulating substrate 1. An internal wiring layer 5 formed inside and a via-hole conductor 7 connecting these wiring layers are configured. These surface wiring layer 3, internal wiring layer 5, and via-hole conductor 7 contain any one of Au, Ag, and Cu as a main component.

  According to the present invention, it is important that at least two or more insulating layers having a glass phase and having different firing shrinkage start temperatures are laminated. For example, the insulating substrate 1 includes seven insulating layers 11 to 23, and among these insulating layers, for example, the insulating layer 11 and the insulating layer 23 are first insulating layers. On the other hand, the insulating layers 13 to 21 are second insulating layers that are different in composition from the insulating layers 11 and 23, which are the first insulating layers, and whose firing shrinkage start temperature is higher than that of the first insulating layer. is there.

  Note that the number of stacked insulating substrates 1 may be 2 to 50 layers, for example. Moreover, the thickness of the insulating layers 11-23 can be 3-300 micrometers, for example. Furthermore, the insulating layers 13 to 21 can be either the first insulating layer or the second insulating layer as long as the shrinkage can be sufficiently limited.

  In FIG. 1, one type of insulating layer is arranged between the wiring layers, but a plurality of types of insulating layers may be arranged between the wiring layers.

  As described above, by firing by combining two types of insulating layers having different shrinkage start temperatures, the force to suppress mutual shrinkage in the planar direction becomes strong, and the firing shrinkage rate in the planar direction is 5% or less, particularly 2%. Hereinafter, it can be optimally 1% or less.

  That is, at the temperature at which the insulating layer 11 and the insulating layer 23 made of the first insulating layer start firing shrinkage, they are restrained by the insulating layers 13 to 21 made of the second insulating layer that have not yet started firing shrinkage. Thus, contraction in the plane direction is limited. After that, the insulating layer 13 to the insulating layer 21 made of the second insulating layer are restrained by the insulating layers 11 and 23 made of the first insulating layer that have already started firing shrinkage at a temperature at which the firing shrinkage starts. Thus, contraction in the plane direction is limited. In this way, the contraction in the planar direction can be limited and the contraction amount in the planar direction can be reduced to 5% or less, so that variation in the contraction amount in the planar direction can also be suppressed.

  In order to more effectively limit the shrinkage in the planar direction, it is desirable that the first insulating layer substantially contracts the firing shrinkage when the second insulating layer starts firing shrinkage.

  Here, the term “shrinkage shrinkage is almost finished” means that shrinkage of 98% or more of the final firing volume shrinkage is finished, and the temperature at which 98% shrinkage is called the shrinkage completion temperature. On the other hand, the shrinkage start temperature refers to a temperature at which the final firing volume shrinkage has shrunk by 2%.

  According to the wiring board of the present invention, the total amount of B2O3 and the alkali metal oxide of the first insulating layer is 10% or less, the glass of the first insulating layer contains F, and the first insulating layer It is important that the content of F is 1 to 6% by mass. The total amount of B2O3 and alkali metal oxide is a value obtained by converting the contents of B and alkali metal in the insulating layer into oxides.

  Further, the total amount of B2O3 and alkali metal oxide in the second insulating layer is smaller than that in the first insulating layer, and the F content in the second insulating layer is smaller than that in the first insulating layer. It is desirable.

The amounts of B ₂ O ₃ and alkali metal oxide are values obtained by converting B and alkali metal elements in the insulating layer into oxides, and B ₂ O ₃ and alkali metal oxide in the insulating layer. There is no need to exist in the form.

  Examples of such an alkali metal element include Li, Na, and K, and Li is most preferable because it has a high effect of lowering the softening point of glass and is easily crystallized. And since an alkali metal element tends to form a hydrate, it is desirable to use it in the state of glass powder.

  Also, although it can be used in the form of an alkali metal carbonate, since the carbonate melts in the glass in the firing stage, even if added as a carbonate, the function to improve the sinterability is used as a glass It is the same.

  Moreover, about B, since it is easy to form a hydrate, it is desirable to use it in the state of glass powder. In addition, about B, since it is easy to form a hydrate, it is desirable to exist in glass after baking.

In the first insulating layer that is fired and shrunk on the low temperature side, the total amount of B2O3 and the alkali metal oxide is 10% or less, so that the glass phase by the addition of B ₂ O ₃ in the firing temperature range of the first insulating layer It is possible to minimize a decrease in the crystallization rate and a decrease in the insulation resistance value due to the addition of an alkali metal oxide. In addition, by containing 1 to 6% by mass of F, the firing shrinkage start temperature of the first insulating layer is effectively lowered, and by promoting crystallization, rigidity in the firing temperature range is increased. Therefore, when the second insulating layer starts firing shrinkage, the shrinkage in the planar direction can be effectively suppressed, and the resistance to deformation such as warping of the wiring board is increased. It becomes a substrate.

  Such a 1st insulating layer can be produced by baking the molded object produced by mixing the glass powder which has crystallinity, and ceramic powder, for example. The glass powder having crystallinity is generally called crystallized glass and has a property that crystals are precipitated from amorphous glass by heating. Moreover, even if the glass powder alone does not precipitate crystals, crystals can be precipitated in combination with ceramic powder, so such a combination may be used.

  Components constituting the first insulating layer and the second insulating layer will be described below.

F lowers the softening point of the glass and increases the fluidity at high temperatures, so that it has the function of increasing the sinterability of the insulating layer and promotes the crystallization of the glass. It has the function of improving the rigidity of the substrate and the strength of the substrate after sintering. The same effect can be obtained by containing B ₂ O ₃ and an alkali metal oxide in combination, but the above effect can be obtained in a smaller amount by containing F.

  When the content of F is more than the above range, the chemical resistance is deteriorated. On the other hand, when the amount is less than the above range, the rate of crystallization of the glass decreases, and the rigidity of the first insulating layer is insufficient and the strength deteriorates. In particular, in the first insulating layer, when the second insulating layer starts firing shrinkage due to insufficient rigidity, the force for restraining the shrinkage in the planar direction is not sufficient, and the substrate is warped by 5% or more. Or other deformations. Moreover, since the softening point of glass becomes high, it becomes difficult to start baking shrinkage at a temperature lower than that of the second insulating layer. A particularly desirable range of F is 2 to 5% for the first insulating layer and 1 to 4% for the second insulating layer.

B ₂ O ₃ is a glass network former and at the same time has a function of lowering the softening temperature and the melting temperature, and when B ₂ O ₃ is in the above range in the total amount with the alkali metal oxide. The glass transition point of the glass can be lowered at the same time that it is easy to produce industrially at low cost, while B ₂ O ₃ is also a component that suppresses crystallization of the glass.

When the content is more than the above range in the total amount with the alkali metal oxide, the chemical resistance is remarkably deteriorated and the glass is crystallized insufficiently and softened and flowed in the firing temperature range. Therefore, when the rigidity of the first insulating layer is insufficient and the second insulating layer starts firing shrinkage, the force for restraining the shrinkage in the plane direction is not sufficient and the shrinkage may be 5% or more. Or deformation such as warping of the substrate. A particularly desirable range of B ₂ O ₃ is 3 to 8% by mass in the first insulating layer and 2 to 7% by mass in the second insulating layer. In particular, it is desirable to include the entire amount in the glass powder.

Alkali metal oxide is a modified body of glass and has a function of lowering the softening temperature and the melting temperature. When the alkali metal oxide is in the above range with the total amount of B ₂ O ₃ , the glass transition point of the glass can be lowered at the same time that it becomes easy to produce industrially inexpensively, while the alkali Metal oxide is also a component that lowers the insulation resistance value of glass.

If the content of B ₂ O ₃ is more than the above range, the insulation resistance values of the first insulating layer and B are lowered, and a defect such as a short circuit occurs in the wiring board. There is a high possibility that A particularly desirable range of the alkali metal oxide is 0.1 to 2% in the first insulating layer and 0.05% to 1.5% in the second insulating layer. In particular, it is desirable to include the entire amount in the glass powder.

ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO ₂ have the effect of promoting glass crystallization and lowering the shrinkage start temperature. When the total amount of at least one selected from the group consisting of ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO ₂ is less than the above range, crystallization is insufficient and the firing shrinkage start temperature is high. Become. On the other hand, when the total amount is larger than the above range, it becomes difficult to obtain a dense glass ceramic sintered body. A particularly desirable range of the total amount of at least one selected from the group consisting of ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO ₂ is 2 to 4% by mass in the first insulating layer, In 2 insulation layers, it is 1-3 mass%.

Examples of the first insulating layer glass phase include SiO ₂ —F—B ₂ O ₃ glass, SiO ₂ —F—B ₂ O ₃ —MO glass, SiO ₂ —F—B ₂ O ₃ —. Examples thereof include borosilicate glass such as Al ₂ O ₃ —MO glass and Bi glass. These glass phases may be so-called residual glass phases in which the composition of the glass in the glass ceramic material is changed with the crystallization during firing from the unfired powder state.

Furthermore, in the present invention, a crystal phase, for example, Al ₂ O ₃ , ZnSiO ₄ , ZrO ₂ , MgSiO ₃ , Mg ₂ SiO ₄ , MgAl ₂ O ₄ , ZnAl ₂ O ₄ , without departing from the scope of the present invention, CaAl ₂ Si ₂ O ₈ , SrAl ₂ Si ₂ O ₈ , Ca ₂ MgSi ₂ O ₇ , Sr ₂ MgSi ₂ O ₇ , Ba ₂ MgSi ₂ O ₇ , ZrSiO ₄ , CaMgSi ₂ O ₆ , CaSiO ₃ , CaZrO ₃ , SrSiO ₃ , BaSiO _{3 and the} like can be mixed.

In particular, it is desirable to contain an Al ₂ O ₃ crystal phase in terms of high chemical resistance and high bending strength.

  In order to increase the rigidity of the first insulating layer and more effectively limit the shrinkage in the planar direction, the glass powder used for the first insulating layer is crystallized glass in which a crystal layer is deposited by firing. It is preferable. Further, the two types of insulating layers have a firing shrinkage start temperature of the first insulating layer that is 10 ° C. or more, more preferably 50 ° C. or more, and preferably 80 ° C. or more lower than the firing shrinkage start temperature of the second insulation layer. This is preferable because superposition of the shrinking temperature range is reduced.

  The insulating layer 11, the insulating layer 23, and the insulating layers 13 to 21 can all be fired at 1050 ° C. or lower, and the wiring layer is formed using a low-resistance conductor such as Cu, Ag, or Au. Is possible.

  The first insulating layer and the second insulating layer are designed according to the purpose by changing various porcelain characteristics such as relative dielectric constant, bending strength, dielectric loss, thermal conductivity, and temperature coefficient. be able to.

  Furthermore, an insulating layer other than the first insulating layer and the second insulating layer may be added. There may be a plurality of types of insulating layers other than the first insulating layer and the second insulating layer.

  Next, a method for manufacturing a wiring board according to the present invention will be described in detail.

  In the method for manufacturing a wiring board according to the present invention, first, a first insulating layer molded body that becomes the first insulating layer after firing, and a second insulating layer after firing, the firing shrinkage starting temperature becomes the first insulating layer molding. A second insulating layer molded body higher than the body is prepared.

  As the composition of the first insulating layer molded body, it is desirable to use a glass powder in which the total amount of B2O3 and the alkali metal oxide is 10% or less and the F content is 1 to 6% by mass. . As a result, it is possible to effectively lower the firing shrinkage start temperature of the first insulating layer molded body and promote crystallization while minimizing the reduction in the crystallization rate and the insulation resistance value of the glass. Since it becomes easy, it is important from the viewpoint that it is possible to suppress the shrinkage of the second insulating layer in the planar direction, to suppress the warp of the wiring board, and to improve the strength.

Furthermore, the first insulating layer molded _{article, ZrO 2, CeO 2, Y} 2 O 3, at least one selected from SnO 2, TiO ₂ groups in the total amount to contain 1 to 5 mass% The crystallization of the glass is promoted, and the shrinkage in the planar direction can be more effectively suppressed when the second insulating layer starts firing shrinkage, and the shrinkage start temperature is lowered. Therefore, it is more desirable from the viewpoint that shrinkage can be started more reliably at a temperature lower than the shrinkage start temperature of the second insulating layer.

  As the composition of the second insulating layer molded body, the total amount of B2O3 and the alkali metal oxide is smaller than that of the first insulating layer molded body, and the content of F is smaller than that of the first insulating layer molded body. It is desirable. Similar to the effects of the first insulating layer molded body described above, it is easy to promote crystallization while minimizing the decrease in the crystallization rate and the insulation resistance value of the glass. It is desirable from the standpoint that it is possible to improve the temperature, and that the firing shrinkage start temperature can be more reliably set higher than the firing shrinkage start temperature of the first insulating layer molded body.

The second insulating layer molded body contains at least one selected from the group consisting of ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO ₂ , and the total amount thereof is the first insulating layer molded body. Is less than the point that it is possible to promote the crystallization of glass and improve the strength of the wiring board, and more reliably shrink at a temperature higher than the shrinkage start temperature of the first insulating layer molded body. It is more desirable from the point that it is possible to start.

  The first insulating layer and the second insulating layer formed by firing the first insulating layer molded body and the second insulating layer molded body are used for simultaneous firing of low-melting-point wiring layers such as Cu, Ag, and Au. Therefore, it is necessary to fire at a low temperature of 1050 ° C. or lower. Therefore, the glass powder is softened at a low temperature and is composed of glass ceramics that are fired at a low temperature by the softening flow.

  First, the glass powder and ceramic powder which comprise the 1st insulating layer molded object and the 2nd insulating layer molded object are prepared as raw material powder.

  These glass powder and ceramic powder are mixed to produce two types of insulating layer molded bodies having different firing shrinkage behaviors.

  Further, the amount of the glass powder is preferably 60 to 95% by mass, particularly 70 to 90% by mass, because it is possible to secure a reduction in the firing shrinkage and good sinterability of the insulating layer. The balance is ceramic powder.

The ceramic powder is not particularly limited as long as it does not depart from the scope of the present invention. For example, Al ₂ O ₃ , ZnSiO ₄ , ZrO ₂ , MgSiO ₃ , Mg ₂ SiO ₄ , MgAl ₂ O ₄ , ZnAl ₂ O ₄ , CaAl ₂ Si ₂ O ₈ , SrAl ₂ Si ₂ O ₈ , BaAl ₂ Si ₂ O ₈ , Ca ₂ MgSi ₂ O ₇ , Sr ₂ MgSi ₂ O ₇ , Ba ₂ MgSi ₂ O ₇ , ZrSiO ₄ , CaMgSi ₂ O ₆ , CaSiO ₃ , CaZrO ₃ , SrSiO ₃ , BaSiO _{3 and the} like can also be selected.

  By selecting the composition of glass powder, the amount of glass powder, the type and amount of ceramic powder, various porcelain characteristics such as relative dielectric constant, bending strength, dielectric loss, thermal conductivity, temperature coefficient, etc., depending on the purpose It is possible to design materials with different

As the ceramic powder, Al ₂ O ₃ is particularly preferable in terms of high chemical resistance and high bending strength.

  A raw material powder of these two types of insulating layer molded bodies, an organic binder, an organic solvent, and, if necessary, a plasticizer are mixed to produce a ceramic slurry.

  Using this ceramic slurry, a green sheet is produced by a known forming method such as a lip coater method or a doctor blade method. In some cases, one of the insulating layers can be pasted and the insulating layer can be formed by printing.

  Next, through holes are formed in the green sheet by punching or the like, and a conductive paste is filled in the through holes, and the surface wiring layer and the internal wiring layer are screen printed or gravure printed using the conductive paste. It is formed by a known printing method.

  The first insulating sheet to be the first insulating layer made of each green sheet and the second insulating sheet to be the second insulating layer obtained in this manner are stacked in accordance with a predetermined stacking order to be stacked. After the body is formed, it is fired.

  In firing, the temperature is raised and reaches the contraction start temperature of the first insulating sheet, and then the temperature is gradually increased, or the contraction start temperature, or the contraction start temperature of the second insulating sheet is equal to or higher than the contraction start temperature. The temperature inside the furnace is temporarily maintained at a lower temperature, and the first insulating sheet is maintained until firing of 90% or more of the final shrinkage proceeds. At this time, the first insulating sheet is baked and shrunk in the thickness direction because the shrinkage in the plane direction is suppressed by the second insulating sheet that is not baked and shrunk at that temperature.

  Thereafter, after the first insulating sheet contracts by 90% or more of the final contraction rate, the temperature is raised to the contraction start temperature of the second insulating sheet and fired. By this firing, the second insulating sheet is restrained from firing shrinkage in the plane direction by the first insulating layer resulting from the first insulating sheet that has been almost sintered, and shrinks in the thickness direction. As a result, both the first insulating sheet and the second insulating sheet are suppressed from firing shrinkage in the planar direction, and a substrate with high dimensional accuracy that is fired and shrunk in the thickness direction can be manufactured.

  The obtained sintered body is subjected to a pretreatment such as alkali degreasing and glass etching as necessary, and then subjected to a plating treatment such as Ni-Au, Cu-Au, etc. Obtainable.

  First, an insulating sheet was produced as follows. The composition of the porcelain after firing the glass powders A1 to A17 and B1 to B6 having an average particle diameter of 2.0 μm shown in Tables 1 and 3 and the alumina powder having an average particle diameter of 2.0 μm is shown in Tables 2 and 4. A1 to a17 and b1 to b6 are weighed, an acrylic binder as an organic binder, and toluene as an organic solvent are mixed to prepare a slurry, which is used to prepare a green sheet by a doctor blade method, and a wiring board Insulating sheet for use.

  In addition, the 1st insulating layer of Table 2 mixes 75 mass% of glass powder of Table 1, and 25 mass% of alumina powder. The second insulating layer in Table 4 is obtained by mixing 60% by mass of the glass powder of Table 3 and 40% by mass of alumina powder.

  A through-hole is formed in a predetermined position of the obtained insulating sheet by punching or the like, and the through-hole is filled with a conductive paste containing Ag powder having an average particle size of 5 μm, and the conductive paste is screened on the surface of the insulating sheet. After printing to form a wiring pattern, this was dried.

  And the insulating sheet which formed these wiring patterns was used as the 1st insulating layer molded object A and the 2nd insulating layer molded object B.

  Next, the first insulating layer molded body and the insulating sheet, which is the second insulating layer molded body, were alternately stacked so that the laminated form in the thickness direction had a 9-layer configuration of ABABABABA, thereby creating 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 900 ° C. for 1 h to produce a multilayer substrate. Moreover, the wiring board of this invention was produced by performing Ni-Au plating processing after pre-processing. In addition, the thickness of each insulating layer 11-23 was 0.05 mm, and the magnitude | size of the multilayer substrate was 70 mm long and 70 mm wide.

  Next, the shrinkage ratio between points of 65 mm in length was measured for both the front and back surfaces of the multilayer molded body before firing and the multilayer substrate after firing, and the value with the larger shrinkage ratio is shown in Table 5. As the dimensional accuracy in the planar direction, the difference between the maximum value and the minimum value of the shrinkage rate was evaluated. The n number was 22, and the difference between the maximum value and the minimum value of shrinkage rate was ± 0.1% or less, and the results are shown in Table 5.

  In addition, the uneven shape of the central 65 mm square portion of the substrate surface is measured using a laser type three-dimensional shape measuring instrument, and the height difference between the highest point and the lowest point on the two diagonal lines of that portion (square) is large. Was the warp value of the substrate. The n number was 22. Table 5 shows the results of the maximum value of warpage, with the maximum value of warpage being 200 μm or less.

  In addition, the insulation resistance value of the first insulating layer was measured. A 10 mm square conductive paste serving as a counter electrode was formed at the same plane position on the front and back surfaces of the first insulating layer molded body A1 by the above-described screen printing method to obtain a first insulating layer molded body A1 with electrodes. Furthermore, four sheets of the first insulating layer molded body A and the second insulating layer molded body B were prepared, through holes serving as via holes were formed at the same plane position, and the conductive paste was filled.

  Next, while aligning so that the laminated form is ABABA1BABA and via holes formed in the insulating sheet other than the first insulating layer molded body A1 with electrodes are electrically connected in the thickness direction. Lamination was performed to prepare a laminated molded body.

The obtained laminated molded body was subjected to a binder removal treatment at 400 ° C. in the atmosphere, and further baked at 900 ° C. for 1 h to obtain an insulation resistance value measurement sample provided with a counter electrode. Resistance measurement terminals were brought into contact with via holes exposed on the front and back surfaces of the sample surface, and the insulation resistance value between the counter electrodes was measured. The n number was 22. The minimum value of the insulation resistance was 1 × 10 ⁹ Ω or higher, and the minimum value of the insulation resistance is shown in Table 5. It should be noted that an insulation resistance value of 1 × 10 ¹² Ω or more is 1 × 10 ¹² Ω, and an n number of 22 is 1 × 10 ¹² Ω or more in the result column> 1 × 10 12 ^It was described as ¹² .

  Moreover, the glass transition point Tg of the glass powder used for the 1st insulating layer and the glass transition point Tg of the glass powder used for the 2nd insulating layer were measured by DTA (implicit thermal analysis). The temperature rising rate was 10 ° C./min. The results are shown in Tables 1 and 3.

Moreover, the shrinkage start temperature and the shrinkage end temperature of each insulating layer were evaluated by the temperature range of 40 ° C. to 1000 ° C. by TMA (thermomechanical analysis) in the atmosphere for the firing shrinkage start temperature and shrinkage end temperature of each insulating sheet. . The results are shown in Table 2 and Table 4.

  In the sample in which the composition of the first insulating layer and the second insulating layer is within the range of the present invention, the shrinkage rate is 5% or less, the dimensional accuracy is as small as ± 0.1%, and the warpage of the substrate is At 200 μm or more, no defects such as discoloration were observed on the wiring board. As described above, the wiring board of the present invention is characterized by high dimensional accuracy, small deformation such as warpage, and good insulation.

On the other hand, sample No. 1 in which the composition of the first insulating layer or the second insulating layer is outside the scope of the present invention. In 8 to 16, the shrinkage ratio exceeded 5%, the substrate warpage was 200 μm or more, or the insulation resistance value was 1 × 10 ⁹ Ω or less.

Note that the first insulating layer and the second insulating layer was analyzed by X-ray diffraction, it was confirmed that crystals of Al ₂ O ₃ ceramic powder is present. It was also confirmed that F was present in the glass.

It is sectional drawing which shows an example of the wiring board of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Insulating substrate 11, 23 ... 1st insulating layer 13, 15, 17, 19, 21 ... 1st insulating layer 3 ... Wiring layer, surface wiring layer 5 ... Wiring layer , Internal wiring layer 100 ... wiring board

Claims (4)

In a wiring board comprising at least two types of insulating layers made of glass ceramics and having different firing shrinkage start temperatures and a wiring layer, the insulating layer that is fired and shrunk on the low temperature side among the insulating layers is a first insulating layer, When the insulating layer that is baked and shrunk on the higher temperature side than the first insulating layer is the second insulating layer, the glass of the first insulating layer contains F, and the F of the first insulating layer is F. A wiring board, wherein the content of B2O3 and the alkali metal oxide of the first insulating layer is 10% by mass or less. The total amount of B ₂ O ₃ and alkali metal oxide in the second insulating layer is less than that in the first insulating layer, and the F content of the glass in the second insulating layer is the first insulating layer. The wiring board according to claim 1, wherein there are fewer layers. The first insulating layer contains at least one selected from the group consisting of ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO _{2 in} a total amount of 1 to 5% by mass. The wiring board according to 1 or 2. The second insulating layer contains at least one selected from the group consisting of ZrO ₂ , CeO ₂ , Y ₂ O ₃ , SnO ₂ , and TiO ₂ , and the total amount thereof is less than that of the first insulating layer. The wiring board according to claim 3.

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