JP2008109063A - Ceramic multilayer substrate - Google Patents

Abstract

A ceramic multilayer substrate having high dimensional accuracy that can be divided by dividing grooves is provided.
[Solution]
The first insulating layer 3 and the second insulating layer 5, which are sintered at different shrinkage start temperatures, are provided, and the outermost layer 11 includes the first insulating layers 3, 11. The second insulating layers 5 and 13 stacked adjacent to each other are formed, and the dividing groove 7 is formed partway along the first insulating layers 3 and 11, so that the first insulating layer is adjacent to the first insulating layer. The layers 3 and 11 are not completely divided, the effect of suppressing the shrinkage in the surface direction of the entire ceramic multilayer substrate 1 can be maintained high, and can be made almost uniform, and can be easily divided by the dividing grooves 7 and can be dimensional accuracy High ceramic multilayer substrate 1 can be provided.
[Selection] Figure 1

Description

  The present invention relates to a ceramic multilayer substrate in which a dividing groove is provided on a surface used for a semiconductor device, a composite electronic component or the like.

  Conventionally, ceramic multilayer substrates have been widely used for semiconductor devices, composite electronic components, and the like. In general, in the method of manufacturing a ceramic multilayer substrate, in order to efficiently manufacture the ceramic multilayer substrate, dividing grooves 7 are formed in advance on one side or both sides of the ceramic multilayer substrate 1 formed by collecting a plurality of ceramic multilayer substrates in advance. A method is adopted in which the groove is divided as a starting point to obtain a plurality of ceramic multilayer substrates.

  The depth of the dividing groove 7 of the ceramic multilayer substrate 1 is required to be about 20% to 60% of the thickness of the ceramic multilayer substrate 1 when the groove is formed on one side. It is said that about 10% to 30% of that half is necessary when forming the film (for example, see Patent Document 1).

  By the way, in order to improve the dimensional accuracy of a ceramic multilayer substrate, a ceramic multilayer substrate composed of a first insulating layer and a second insulating layer made of different inorganic compositions and having different shrinkage start temperatures is known. (For example, refer to Patent Document 2). According to Patent Document 2, a shrinkage start temperature is low by forming a green laminate with a first insulating layer molded body and a second insulating layer molded body that starts shrinking at a higher temperature than the first insulating layer molded body. When the first insulating layer starts to shrink, shrinkage in the surface direction is suppressed by the second insulating layer in an unsintered state, and when the second insulating layer having a high shrinkage start temperature starts shrinking, it is already baked. The shrinkage in the surface direction is suppressed by the bonded first insulating layer, and the dimensional accuracy of the ceramic multilayer substrate can be improved by suppressing the shrinkage in the surface direction in the firing step.

  Since there is a surface that is not constrained in the outermost layer of such a ceramic multilayer substrate, if the insulating layer disposed in the outermost layer is thickened, the constraining force becomes weaker in the portion near the surface of the ceramic multilayer substrate. The thickness of the outermost layer of the multilayer substrate is designed to be 10% or less of the thickness of the ceramic multilayer substrate.

  Even in such a ceramic multilayer substrate, attempts have been made to improve productivity by providing division grooves on the surface. (For example, see Patent Document 3).

In addition, if a split groove penetrating the first insulating layer is formed on the surface of such a ceramic multilayer substrate, the restraining force on the front surface side becomes weaker than the restraining force on the back surface side, and a concave warp tends to occur. Attempts have been made to reduce the concave warpage by adjusting the depth and number of the dividing grooves on the side.
Japanese Patent Laid-Open No. 10-259063 JP 2004-296721 A Japanese Patent Application No. 2002-545042

  However, when the dividing groove is formed, as described above, it is necessary to form the dividing groove 55 at a depth of 20% to 60% with respect to the thickness of the ceramic multilayer substrate. Therefore, as shown in FIG. The first insulating layer disposed in the outermost layer of the ceramic multilayer substrate 53 is penetrated.

  Then, since the first insulating layer is divided, the restraining force of the first insulating layer with respect to the second insulating layer is reduced, the shrinkage suppressing effect in the surface direction of the ceramic multilayer substrate is reduced, and the dimensions of the ceramic multilayer substrate are reduced. There was a problem that accuracy decreased.

  Patent Document 3 describes that in order to reduce the concave warpage of the ceramic multilayer substrate, more dividing grooves staying in the constraining sheet on the back surface side are formed than on the front surface side. Since the restraining force on the back surface side is adapted to the restraining force on the front surface side that is reduced by penetrating, the shrinkage suppressing effect in the surface direction is lowered, and the dimensional accuracy is lowered.

  In other words, in the case of a ceramic multilayer substrate in which insulation layers having different shrinkage start temperatures are stacked and a binding force is generated between them, and shrinkage in the surface direction of the ceramic multilayer substrate is positively suppressed, The improvement in productivity and the improvement in dimensional accuracy due to the formation of grooves could not be achieved at a high level.

  The present invention has been devised in view of the above drawbacks, and an object thereof is to provide a ceramic multilayer substrate having high dimensional accuracy that can be divided by dividing grooves.

  In the ceramic multilayer substrate of the present invention, a split groove is formed on the surface of each of the sintered first insulating layer and second insulating layer having different shrinkage start temperatures, and a wiring circuit is provided on at least one of the surface and the inside. The ceramic multilayer substrate is arranged, wherein an outermost layer of the ceramic multilayer substrate is composed of the first insulating layer having a thickness of 10% or less of the thickness of the ceramic multilayer substrate, and the second insulating layer is located inside the first insulating layer. And the dividing groove is formed up to the middle of the outermost first insulating layer.

  According to the present invention, by forming the dividing groove partway through the first insulating layer, the first insulating layer is not completely divided by the dividing groove, and the effect of suppressing shrinkage in the surface direction of the ceramic multilayer substrate is enhanced. Therefore, a ceramic multilayer substrate with high dimensional accuracy can be provided.

  Further, since the surface of the outermost layer of such a ceramic multilayer substrate is not restrained, the restraining force is weak in the portion close to the surface and tends to shrink in the surface direction. At this time, if the dividing groove is formed only by the first insulating layer, the force of the surface in the surface direction causes the dividing groove to widen and a residual stress is generated. The force is generated at the deepest portion of the dividing groove. To focus on. Due to this effect, the substrate can be easily divided by the dividing groove.

  As shown in FIG. 1, in the ceramic multilayer substrate 1 of the present invention, the dividing groove 7 is formed on the surface of the laminated body of the first insulating layer 3 and the second insulating layer 5 that are sintered at different shrinkage start temperatures. A wiring circuit (not shown) is arranged on at least one of the surface and the inside.

  The laminated first insulating layer 3 and second insulating layer 5 function so as to suppress the shrinkage in the surface direction of the ceramic multilayer substrate 1 in the firing process, and the shrinkage in the surface direction is extremely small. can do. The smaller the shrinkage, the smaller the amount of dimensional variation.

  Moreover, the ceramic multilayer substrate 1 of this invention can divide | segment the ceramic multilayer substrate 1 into a piece by the division | segmentation groove | channel 3 formed in the surface. That is, the ceramic multilayer substrate 1 of the present invention is a collection of a plurality of multilayer substrates, and can be easily divided along the dividing grooves 7.

  In the ceramic multilayer substrate 1 of the present invention, the outermost layer 11 of the ceramic multilayer substrate 1 is composed of the first insulating layers 3 and 11 that are 10% or less of the thickness of the ceramic multilayer substrate, and the second insulating layers 5 and 13 are the first insulating layers. It is important that the first insulating layers 3 and 11 are in contact with each other and laminated, and the dividing grooves 7 are formed partway along the first insulating layers 3 and 11.

  That is, since the depth of the dividing groove 7 is shallower than the thickness of the outermost first insulating layers 3 and 11, the outermost first insulating layers 3 and 11 may be divided by the dividing groove 7. Therefore, even when the dividing grooves 7 are provided, the first outermost layer with respect to the second insulating layers 5 and 13 stacked in contact with the inner sides of the first outermost insulating layers 3 and 11 in the firing step is provided. Reduction of the restraining force of the insulating layers 3 and 11 can be suppressed, shrinkage in the surface direction of the ceramic multilayer substrate 1 can be sufficiently suppressed, and the amount of dimensional variation of the ceramic multilayer substrate 1 can be reduced. It is.

  The depth of the dividing groove 7 is preferably 3% or more, more preferably 5% or more of the ceramic multilayer substrate 1.

  This is due to the effects described below. That is, since the surface of the outermost layer 11 of the ceramic multilayer substrate 1 is not constrained, the constraining force is weak at a portion close to the surface and tends to shrink in the plane direction. At that time, if the dividing groove 7 is formed only by the first insulating layers 3 and 11, the force of the surface in the surface direction causes the width of the dividing groove 7 to widen and a residual stress is generated. It concentrates on the deepest part of the dividing groove 7. Due to this effect, the ceramic multilayer substrate 1 of the present invention can be easily divided by the dividing grooves 7 even if the dividing grooves 7 are formed shallower than in the prior art.

Further, when the coefficient of thermal expansion after firing of the first insulating layer and the second insulating layer is α1 and α2, it is desirable to satisfy 2 × 10 ⁻⁶ / ° C. <(Α1-α2). As a result, the amount of shrinkage of the first insulating layer 3 is larger than that of the second insulating layer 5 in the temperature lowering process of firing, and the interface between the first insulating layers 3 and 11 and the second insulating layers 5 and 13 is caused by this shrinkage difference. Can be concentrated on the deepest portion of the dividing groove 7 formed by only the first insulating layers 3 and 11. Due to this effect, the division groove 7 can be further easily divided, so that the division groove 7 can be formed shallower and the dimensional accuracy can be improved.

  Further, in the present embodiment, it is desirable that the dividing groove 7 is formed so that the deepest portion becomes a point or the width becomes narrower as the depth becomes deeper. This makes it easier for the stress to concentrate on the deepest part of the dividing groove 7, and the ceramic multilayer substrate 1 can be divided more easily.

  The ceramic multilayer substrate 1 of the present invention can be produced, for example, by the following production method.

  The first insulating layer 3 is formed by sintering the first inorganic composition, and as the material of the first inorganic composition, for example, glass that can be fired at a relatively low temperature of 800 ° C. to 1200 ° C. -A ceramic material is preferably used, and its thickness is set to 10 to 300 m, for example. This glass-ceramic material includes glass powder and ceramic powder.

  The second insulating layer 5 is formed by sintering the second inorganic composition, and as the material of the second inorganic composition, a glass-ceramic material is preferably used in the same manner as the first inorganic composition. The thickness thereof is set to, for example, 2 to 150 μm.

  In the present embodiment, the first insulating layer 3 and the second insulating layer 5 are preferably composed of 30 to 100% by weight of glass powder and 0 to 70% by weight of ceramic powder.

As a specific composition of the glass powder, for example, as essential components, SiO ₂ is 10 to 70% by mass, Al ₂ O ₃ is 0.5 to 30% by mass, MgO is 3 to 60% by mass, and optional components , CaO 0 to 35 wt%, a BaO 0-35 wt%, 0-35 _wt% of _SrO, and B 2 _{O 3} 0 to 20 wt%, 0-30 wt% of ZnO, the TiO ₂ 0 The ceramic powder contains Al ₂ O ₃ , SiO ₂ , MgTiO ₃ , CaZrO ₃ , CaTiO ₃ , Mg ₂ SiO, containing 0 to 3% by mass of Na ₂ O and 0 to 5% by mass of Li ₂ O. ₄ , BaTi ₄ O ₉ , ZrTiO ₄ , SrTiO ₃ , BaTiO ₃ , or TiO ₂ is preferable.

  The combination of glass powder and ceramic powder with the above composition allows the dielectric constant to be controlled, making it suitable for circuit miniaturization, low loss due to high dielectric constant, or high-speed transmission due to low dielectric constant. ing. In addition, by controlling various compositions within the above range, the firing shrinkage behavior can be easily controlled and changed. In addition, low-temperature sintering at 1000 ° C. or lower is possible, and low resistance conductors such as silver (melting point 960 ° C.), copper (melting point 1083 ° C.), gold (melting point 1063 ° C.) are used as wiring conductors and via-hole conductors. Thus, a low loss circuit can be created.

  In this way, wiring conductors, via-hole conductors, and the like (not shown) are formed in the surface layer and inside of the laminate including the first insulating layer 3 and the second insulating layer 5. The surface layer wiring conductors mainly function as connection pads for mounting electronic component elements, and the internal wiring conductors interposed between the insulating layers are mainly wirings that electrically connect each circuit element, inductors and capacitors. Functions as a circuit element. The surface layer wiring conductor and the inner wiring conductor, or the inner wiring conductors interposed between different insulating layers are electrically connected by a via-hole conductor.

  The wiring conductor and via-hole conductor are made of a conductive material including any one of the above-described low-resistance conductor materials such as silver, copper, and gold. The wiring conductor is set to have a thickness of, for example, 5 to 25 μm. The diameter of the via hole conductor can be arbitrarily set. When the thickness of the insulating layer in which the via hole conductor is embedded is 10 to 300 μm, the diameter of the via hole conductor is set to 50 to 300 μm, for example.

  First, ceramic green sheets to be the first insulating layer 3 and the second insulating layer 5 after firing are produced. The ceramic green sheet is, for example, mixed with an organic binder, an organic solvent, and, if necessary, a plasticizer in a slurry of the first and second inorganic compositions obtained by combining the glass powder and the ceramic powder, The slurry is obtained by performing tape molding by a doctor blade method or the like and cutting it into a predetermined dimension.

  Next, a through hole is formed in the obtained ceramic green sheet using a method such as punching with a mold, a via paste is formed by filling the through hole with a conductive paste, and on the main surface of the ceramic green sheet A conductor paste is applied by screen printing or the like to form a wiring conductor.

  As a material for the wiring conductor and the via-hole conductor, for example, a paste formed by adding ethyl cellulose as an organic binder and 2-2-4-trimethyl-3-3-pentadiol monoisobutyrate as an organic solvent to silver powder was used. .

  The ceramic green sheets are stacked according to a predetermined stacking order to form a stacked body that becomes the ceramic multilayer substrate 1 after firing.

  Next, the dividing groove 7 is formed along a predetermined dividing line by pressing a blade or a mold on one side or both sides of the obtained laminate.

  At this time, it is necessary to adjust the depth of the dividing groove 7 so that the dividing groove 7 is formed partway through the first insulating layers 3 and 11 after firing. Specifically, the dividing groove 7 may be formed shallower than the thickness of the ceramic green sheet to be the first insulating layers 3 and 11. The ceramic green sheets that become the first insulating layers 3 and 11 after firing of the respective substrate regions defined by the dividing grooves 7 have a structure in which they are connected to each other without being completely divided. When firing the multilayer substrate 1, it is possible to maintain a high shrinkage suppression effect in each substrate region partitioned by the dividing grooves 7, and to substantially uniform the shrinkage suppression effect in the plane direction of the entire ceramic multilayer substrate 1. In addition, deformation due to warpage or the like can be effectively prevented.

  Then, the ceramic multilayer substrate 1 is heated at a temperature lower than the shrinkage start temperature of the second inorganic composition and higher than the shrinkage start temperature of the first inorganic composition, and the first insulating layer 3 is oriented in the plane direction. Compared with the shrinkage start temperature of the second inorganic composition, the laminated body is heated at a temperature higher than the shrinkage start temperature of the second inorganic composition, and the second insulating layer 5 is larger in the thickness direction than the surface direction. Shrink. In this way, the first insulating layer 3 and the second insulating layer 5 are sintered.

  Further, following the firing step, the ceramic multilayer substrate 1 is divided into so-called chocolate breaks along the dividing grooves 7 for each substrate region, thereby obtaining a wiring substrate with high dimensional accuracy.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible within the range which does not deviate from the summary of this invention.

  For example, in the above-described embodiment, the laminate is a laminate of ceramic green sheets that become the first insulating layer 3 and the second insulating layer 5, but the first insulating layer 3 becomes the second insulating layer 5. You may make it form directly by apply | coating the 1st inorganic composition made into the paste form for formation of the 1st insulating layer 3 by printing etc. on the main surface of a ceramic green sheet. In this case, the first insulating layer 3 having a small thickness can be formed relatively easily by applying a paste or the like. Compared with the case where the first insulating layer 3 having a small thickness is formed of a ceramic green sheet or the like, there is an advantage that workability when forming the first insulating layer 3 is improved and productivity can be improved.

  Further, in the above-described embodiment, the ceramic multilayer substrate 1 is configured as a multilayer body, but in addition to this, a multilayer ceramic capacitor, a multilayer ceramic inductor, a multilayer ceramic resonator, a multilayer dielectric filter, or the like may be configured. Is possible.

  To compositions A and B having different shrinkage start temperatures shown in Table 1, ethyl cellulose as an organic binder and 2-2-4-trimethyl-3-3-pentadiol monoisobutyrate as an organic solvent were added, respectively, to prepare a slurry. This was prepared and thinned by a doctor blade method to produce various thickness green sheets for substrates.

  Then, a through hole is formed in a predetermined position of the green sheet by punching or the like, and a conductive paste containing Ag powder is filled in the through hole, and a predetermined inner layer conductor layer is printed by screen printing the conductive paste. Formed and dried.

  On the other hand, the above conductive paste was screen-printed with the pattern of the surface conductor layer on the green sheet which is the outermost layer, which is the uppermost layer and the lowermost layer, and was dried.

  A green sheet filled with a conductive paste and formed with a conductor having a predetermined shape is laminated in the combination shown in Table 2, and a green sheet having a conductor film formed as a surface layer conductor is laminated on the uppermost layer and the lowermost layer. The body was made. And the depth which presses a blade on both surfaces of this laminated body was adjusted, and as shown in Table 2, 10 samples each with different depths of the dividing grooves on the surface or front and back surfaces of the laminated body were produced.

  Thereafter, the ceramic multilayer substrate in which the debinding treatment is performed at 400 ° C. in the atmosphere, and further, baked at 910 ° C. to form an insulating layer in which all the green sheets are sintered, and divided grooves having various depths are formed. Was made. In addition, the thickness of the 1st insulating layer and the thickness of the 2nd insulating layer were the thickness shown in Table 2. The ceramic multilayer substrate had a thickness of 10 mm in length and 10 mm in width as shown in Table 2.

  In addition, before and after firing, the length between predetermined points was measured for the green sheet laminate and the fired ceramic multilayer substrate, and the shrinkage in the surface direction of the ceramic multilayer substrate was measured. In addition, the shrinkage rate was measured for each sample, and the difference between the maximum value and the minimum value of the shrinkage rate of 10 samples was evaluated as shrinkage variation. Moreover, it was confirmed whether each ceramic multilayer board | substrate obtained by making a chocolate break was divided | segmented along the division | segmentation groove | channel with the visual microscope, and division property was confirmed.

Further, a wax is added to each of the composition A and the composition B and pressed at 98 MPa to form a green compact, and the green compact is heated to room temperature to 1000 by TMA (thermomechanical analysis) in the air. The shrinkage start temperature, shrinkage end temperature, and thermal expansion coefficient of the compositions A and B were evaluated in the temperature range of ° C.

  As shown in Table 2, it can be seen that the ceramic multilayer substrate of the present invention has no division failure, the shrinkage rate is as small as 1%, and the shrinkage variation is excellent at 0.1%.

It is sectional drawing of the ceramic multilayer substrate which concerns on one Embodiment of this invention. It is a top view of the conventional ceramic multilayer substrate. It is sectional drawing of the conventional ceramic multilayer substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ceramic multilayer substrate 3 ... 1st insulating layer 5 ... 2nd insulating layer 7 ... Dividing groove 11 ... 1st insulating layer 13 of outermost layer ... 1st insulation of outermost layer Second insulating layer laminated in contact with the inside of the layer

Claims (1)

A ceramic multilayer substrate in which split grooves are formed on the surface of each sintered first insulating layer and second insulating layer, each having a different shrinkage start temperature, and a wiring circuit is disposed on at least one of the surface and the inside. The outermost layer of the ceramic multilayer substrate is composed of the first insulating layer having a thickness of 10% or less of the thickness of the ceramic multilayer substrate, and the second insulating layer is laminated in contact with the inner side of the first insulating layer. The multi-layered ceramic substrate is characterized in that the dividing groove is formed partway along the outermost first insulating layer.

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