JP4841448B2 - Divided grooved wiring board and manufacturing method thereof - Google Patents

Description

  The present invention relates to a wiring substrate with divided grooves provided with divided grooves on a surface used for a semiconductor device, a composite electronic component, and the like, and a method for manufacturing the same.

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

  The depth of the dividing groove of the wiring substrate with such a dividing groove needs to be about 20% to 60% of the thickness of the wiring substrate 1 with the dividing groove when the groove is formed on one side. Is formed on both sides, about 10% to 30% of that half is required (see, for example, Patent Document 1).

By the way, in order to improve the dimensional accuracy of the wiring substrate with divided grooves, the wiring substrate with divided grooves is formed by laminating the first insulating layer and the second insulating layer made of different inorganic compositions and having different shrinkage start temperatures. Is known (see, for example, 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 wiring substrate with divided grooves can be improved by suppressing the shrinkage in the surface direction in the firing step.
Japanese Patent Laid-Open No. 10-259063 JP 2004-296721 A

  However, even in the wiring substrate with a dividing groove described in Patent Document 2, in order to divide the dividing groove from the starting point, the opening width of the outermost part of the dividing groove is required to be about 50 to 100 μm, and the division on one side is also performed. The depth of the groove needs to be about 10 to 30% of the substrate thickness. In the wiring substrate with divided grooves, the shrinkage in the plane direction is reduced, but the shrinkage in the thickness direction is increased. Therefore, the shrinkage of the divided grooves is also small in the plane direction during firing, but the shrinkage in the thickness direction is increased.

  For this reason, the tip of the dividing groove is deformed or buried by sintering shrinkage of the ceramic component during firing, and when the substrate is divided, defects in appearance such as burrs and chips are likely to occur.

  In other words, the wiring substrate with divided grooves described in Patent Document 2 is more careful with the state of the tip of the dividing groove during the baking process than the conventional wiring substrate with divided grooves, as it shrinks in the direction of the substrate thickness. There is a need to.

  Further, in recent years, it is required to provide as many product pieces as possible in a wiring substrate with divided grooves from the viewpoint of cost reduction of the substrate. Therefore, it has become necessary to reduce the allowable area for forming the dividing grooves. One of the countermeasures is to make the groove width of the dividing groove narrow. However, in the wiring board with the dividing groove described in Patent Document 2, when the dividing groove is formed thin, the tip of the dividing groove is also formed. There was a tendency for the thinned portion to fill the tip of the dividing groove during firing, to a greater degree of deformation, and to increase appearance defects.

  As a measure for improving this, there is a method of forming a dividing groove by dicing the substrate after firing, but there is a problem that the cost becomes high.

  The present invention has been devised in view of the above-described drawbacks, and is formed by laminating insulating layers having different firing start temperatures, and even when a thin or shallow dividing groove is formed, with a dividing groove that suppresses the occurrence of division defects. It is to provide a wiring board and a manufacturing method thereof.

  The wiring substrate with divided grooves according to the present invention includes a wiring substrate and an insulating substrate composed of a sintered first insulating layer, a second insulating layer that starts shrinking at a higher temperature than the first insulating layer, and is sintered. The provided wiring board region is a wiring substrate with divided grooves assembled through a divided region in which divided grooves are formed, and the glass amount of the insulating layer in the divided region is equal to the glass of the insulating layer in the wiring substrate region. It is characterized by being larger than the amount.

  The method for manufacturing a wiring substrate with divided grooves according to the present invention includes a first green sheet and a second green sheet having a shrinkage start temperature higher than that of the first green sheet on a surface that becomes a divided region after firing. A step of arranging a glass paste or glass sheet containing glass powder, a step of laminating the first green sheet and the second green sheet on which the glass paste or the glass sheet is arranged, and producing a laminate, A step of forming a split groove on a surface to be a divided region after firing the laminate, and heat-treating the laminate provided with the split groove to soften the glass powder contained in the glass paste or the glass sheet, The glass component in which the glass powder is softened is at least one of the first green sheet and the second green sheet. Wherein the step of infiltrating, by comprising a step of sintering thereafter the first green sheet and the second green sheet.

  According to the wiring substrate with divided grooves of the present invention, the divided region is easily broken by increasing the glass amount of the insulating layer in the divided region more than the glass amount of the insulating layer in the wiring substrate region where the wiring substrate is formed. It becomes easy to divide by the dividing groove formed in the divided region. For this reason, it is possible to form a dividing groove that is narrower than the conventional one.

  Further, according to the method for manufacturing a wiring substrate with divided grooves of the present invention, the glass amount of the insulating layer in the divided region can be made larger than the glass amount of the insulating layer in the wiring substrate region where the wiring substrate is formed. A wiring substrate with divided grooves that can be easily divided by the divided grooves can be easily manufactured.

  As shown in FIG. 1, the divided grooved wiring board 1 according to the present invention has divided grooves 7 on the surface of the laminated body of the first insulating layer 3 and the second insulating layer 5, which have different shrinkage start temperatures. A wiring circuit (not shown) is formed on at least one of the surface and the inside.

  A region where the division groove 7 of the wiring substrate 1 with the division groove is formed is a division region 9, and a portion surrounded by the division region 9 is a wiring substrate region 13 where the wiring substrate 11 is formed.

  According to the wiring substrate 1 with divided grooves of the present invention, it is important that the glass amount of the insulating layer in the divided region 9 is larger than the glass amount of the insulating layer in the wiring substrate region 13.

  An insulating layer with a large amount of glass has a lower resistance to breakage than an insulating layer with a small amount of glass, and is easily broken. Therefore, the divided grooved wiring board 1 of the present invention having the divided region 9 having a larger glass amount than the insulating layer of the wiring substrate region 13 can be easily divided into individual pieces by the divided groove 7. Even if the width of the groove is reduced or the depth of the dividing groove 7 is reduced, it can be easily divided.

  And the wiring board 1 with a division | segmentation groove | channel where the glass amount of such an insulating layer of the division area 9 is larger than the glass quantity of the insulation layer of the wiring board area | region 13 can be easily produced with the following manufacturing methods.

  First, as shown in FIGS. 2A and 2B, the first green sheet 13 that becomes the first insulating layer 3 after firing, and the shrinkage start temperature is higher than that of the first green sheet 13, and firing is performed. A second green sheet 15 to be the second insulating layer 5 later is prepared.

  These first green sheet 13 and second green sheet 15 are, for example, an organic binder, an organic solvent, and, if necessary, a plasticizer mixed with a powder of an inorganic composition obtained by combining glass powder and ceramic powder. The slurry can be made into a slurry, tape-molded by the doctor blade method using this slurry, and cut into a predetermined size.

  Next, as shown in FIG. 2 (c), a glass paste 17 containing glass powder is applied to the surface to be a divided region of at least one surface of the first green sheet 13 and the second green sheet 15. To do.

  Or you may laminate | stack the glass sheet 19 containing the glass powder formed in the sheet form, for example, as shown in FIG.2 (d), without using this glass paste.

  The glass paste 17 may be obtained by appropriately mixing glass powder, a binder, and a solvent. Moreover, the glass sheet 19 can be produced by performing tape molding by a doctor blade method or the like using a slurry in which glass powder, a binder, and a solvent are appropriately mixed, and cutting the slurry into predetermined dimensions.

  Next, as shown in FIGS. 3E and 3F, the first green sheet 13 and the second green sheet 15 provided with the glass paste 17 or the glass sheet 19 are punched by a mold or the like. A through hole 21 is formed using a method, and a conductor paste is filled in the through hole 21 to form a via hole conductor 23. In addition, the process using glass paste 17 is demonstrated in the process after FIG.3 (e).

  Next, as shown in FIGS. 3G and 3H, a conductive paste is deposited on the main surfaces of the first green sheet 13 and the second green sheet 15 by screen printing or the like to form a wiring pattern 25. Form.

  The material of the via-hole conductor 23 and the wiring pattern 25 is, 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. Can be used.

  Next, as shown in FIG. 4 (i), the first green sheet 13 and the second green sheet 15 on which the via-hole conductor 23 and the wiring pattern 25 are formed are stacked in accordance with a predetermined stacking order. Then, the laminated body 27 is formed. In FIG. 4I and subsequent figures, the via hole conductor 23 and the wiring pattern 25 are not shown. In the production of the laminate 27, the glass paste 17 is not exposed on the surface of the laminate 27 in order to prevent the wiring substrate region 13 from being wet and spread, and the first green sheet 13 and the second green sheet 15. It is desirable to arrange at the interface.

  Next, as shown in FIG. 4 (j), the divided region 9 in which the glass paste 17 of the laminate 27 is arranged on one or both sides of the obtained laminate 27 using a cutting blade (not shown) and A dividing groove 7 is formed in the region to be formed.

  Then, by firing the laminated body 27 in which the divided grooves 7 are formed, the glass powder contained in the glass paste 17 wets and spreads on the first green sheet 13 and the second green sheet 15 in the firing process, and the divided regions 9. 1 can be produced, as shown in FIG. 1, in which the amount of glass is larger than the amount of glass in the wiring substrate region 13.

  As described above, since the glass is infiltrated into the first green sheet 13 and the second green sheet 15, the distribution of the glass amount is generated in the divided region 9, but even in that case, the division property is sufficiently improved. Can be made.

  In the method for manufacturing a wiring board with divided grooves of the present invention, it is important that the glass powder used for the glass paste 17 and the glass sheet 19 has a softening point lower than the shrinkage start temperature of the second green sheet 15. It is.

  That is, among the green sheets, by using the glass powder that has already been softened at the shrinkage start temperature of the second green sheet 15 having a high shrinkage start temperature, the glass powder is applied to the second green sheet 15 that has not been densified. Since it can move by being softened, the glass amount of the second insulating layer 5 in the divided region 9 can be increased.

  Further, when glass powder having a softening point lower than the shrinkage start temperature of the first green sheet 13 is used as the glass powder used for the glass paste 17 and the glass sheet 19, the first green sheet 13 and the first green sheet 13 Since the glass powder softens before the second green sheet 15 starts to shrink, the glass powder can soften and move to the first green sheet 13 and the second green sheet 15 that are not densified. The glass amount of the first insulating layer 3 and the second insulating layer 5 in the divided region 9 can be increased.

  In this firing, the first and second green sheets 13 and 15 have a lower shrinkage start temperature than the lower one, and the first and second green sheets 13 and 15 shrink. Once heated at a temperature lower than the shrinkage start temperature of the green sheet with the higher start temperature, the inorganic composition of the green sheet with the lower shrinkage start temperature is shrunk greatly in the thickness direction compared to the surface direction, and then The laminated body 27 is further heated at a temperature higher than the contraction start temperature of the green sheet having the higher contraction start temperature of the first and second green sheets 13 and 15, and the green sheet having the higher contraction start temperature. Wiring board 1 with divided grooves in which shrinkage and shrinkage variation in the plane direction are suppressed by greatly shrinking the inorganic composition in the thickness direction as compared with the surface direction. It can be produced.

  In addition, after this firing step, if necessary, after plating and mounting an electric element, the wiring substrate 1 with divided grooves is divided into individual pieces along the dividing grooves 7 for each wiring substrate region 13. As a result, the wiring substrate 11 which is flat and has high dimensional accuracy is obtained.

  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, the slurry that becomes the first green sheet 13 may be applied directly to the surface of the second green sheet 3 by a doctor blade method or the like. In this case, the through hole 21 may be formed by integrally punching the first green sheet 13 and the second green sheet 15. In such a case, for example, the thickness of the first green sheet 13 can be easily made thinner than that of the second green sheet 15.

  Further, when a thin green sheet having a thickness of 50 μm or less is used, the through hole 21 may be formed by forming a green sheet on a PET film or the like and punching out the whole PET film.

  The via-hole conductor 23 and the wiring pattern 25 formed on the first and second green sheets 13 and 15 are arranged in a region without the dividing groove 7 and form a wiring circuit after firing.

  The 1st green sheet 13 used with the manufacturing method of the wiring board 1 with a division | segmentation groove | channel of this invention contains ceramic powder and a binder, As this ceramic powder, comparatively low temperature, for example, 800 to 1200 degreeC. A glass-ceramic material that can be fired at 1 is preferably used, and the thickness is preferably set to 2 to 150 μm, for example. This glass-ceramic material includes glass powder and ceramic powder.

  The second green sheet 15 contains a ceramic powder and a binder, and as this ceramic powder, for example, a glass-ceramic material that can be fired at a relatively low temperature of 800 ° C. to 1200 ° C. is suitable. It is desirable that the thickness be set to 10 to 3000 μm, for example. This glass-ceramic material includes glass powder and ceramic powder.

  The first green sheet 13 and the second green sheet 15 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 to be used, 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 as, CaO 0 to 35 wt%, a BaO 0-35 wt%, the SrO 0 to 35 _wt%, B 2 _{O 3} 0 to 20 wt%, the ZnO 0 to 30 wt%, the TiO ₂ 0 to 10% by mass, 0 to 3% by mass of Na ₂ O, 0 to 5% by mass of Li ₂ O, and as ceramic powder, Al ₂ O ₃ , SiO ₂ , MgTiO ₃ , CaZrO ₃ , CaTiO ₃ , Mg ₂ It is desirable that it is at least one selected from SiO ₄ , BaTi ₄ O ₉ , ZrTiO ₄ , SrTiO ₃ , BaTiO ₃ and TiO ₂ .

  The combination of glass powder and ceramic powder with such a composition allows the dielectric constant to be controlled, and it is possible to reduce the size and loss of the circuit by increasing the dielectric constant, or to increase the transmission speed by reducing the dielectric constant. Suitable for 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 patterns and via-hole conductors. Therefore, a low loss circuit can be manufactured.

  The laminated first insulating layer and second insulating layer function so as to suppress shrinkage in the surface direction of the wiring substrate with divided grooves in the firing process, thereby reducing shrinkage in the surface direction. be able to. The smaller the shrinkage, the smaller the amount of shrinkage variation.

  Moreover, the wiring board with a division | segmentation groove | channel of this invention can divide | segment a wiring board with a division | segmentation groove | channel into the piece by the division | segmentation groove | channel 7 formed in the surface. In other words, the wiring substrate with division grooves is a collection of a plurality of wiring substrates and can be easily divided along the division grooves 7.

  In addition, in the surface layer of the laminated sintered body which consists of the 1st insulating layer obtained by baking the 1st green sheet 13, and the 2nd insulating layer obtained by baking the 3rd green sheet 15, and the inside Wiring, via-hole conductors and the like (not shown) are formed. The wiring pattern on the surface layer mainly functions as a connection pad for mounting the electronic component elements, and the internal wiring interposed between the insulating layers mainly includes wiring for electrically connecting each circuit element, inductor, capacitor, etc. Functions as a circuit element. A surface layer wiring and an internal wiring, or an internal wiring interposed between different insulating layers are electrically connected by a via-hole conductor.

  The wiring and via-hole conductors are made of a conductive material including any one of the low-resistance conductor materials such as silver, copper, and gold. The wiring pattern is set to have a thickness of 5 to 25 μm, for example. 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.

  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 a green sheet having a thickness of 50 μm for a substrate.

  Glass paste having a softening point shown in Table 2 and an average particle diameter of 5 μm, an organic binder, and a solvent were mixed to prepare a glass paste.

  Next, a glass paste was applied to the surface to be a divided region of the produced green sheet after drying so that the width was 30 μm and the thickness was 20 μm.

  Then, a through hole is formed by punching or the like at a predetermined position of the green sheet coated with the glass paste, and the conductive paste containing Ag powder is filled into the through hole, and this conductive paste is screen-printed to obtain a predetermined hole. The inner conductor layer was printed 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 having different maximum diameters of the width of the dividing groove were produced on the front surface or the back surface of the laminated body. .

  In preparing the laminate, the glass paste was disposed only at the interface between the green sheets so that the glass paste did not precipitate on the surface of the laminate.

  After this, the binder is removed 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. A wiring board was produced. In addition, the thickness of the 1st insulating layer and the thickness of the 2nd insulating layer were the thickness shown in Table 2. In addition, the size of the wiring substrate with divided grooves was 10 mm in length and 10 mm in width and the thickness shown in Table 2.

  The glass content was calculated by obtaining the crystallinity of the sample glass from the Rietveld method using ZnO as an internal standard material.

  Before and after firing, the length between the predetermined points was measured for the green sheet laminate and the fired divided grooved wiring board, and the shrinkage in the surface direction of the divided grooved wiring board was measured. . In addition, shrinkage | contraction rate was measured about each sample, respectively, and it evaluated as an average value of the shrinkage | contraction rate of ten samples. As a result, the shrinkage variation of the wiring substrate with divided grooves of the present invention was 0.5% or less, which was excellent.

  Moreover, it was confirmed whether each wiring board with a division | segmentation groove | channel obtained by dividing | segmenting into an individual piece was divided | segmented along the division | segmentation groove | channel with the visual microscope.

In addition, a green compact is formed by adding wax to each of the glass sheet, the first insulating layer, and the second insulating layer, and pressing the composition at 98 MPa. The softening point of the glass sheet, the shrinkage start temperature, the shrinkage end temperature, and the thermal expansion coefficient of the composition of the first insulating layer and the second insulating layer were evaluated in a temperature range of room temperature to 1000 ° C. by thermomechanical analysis.

  As shown in Table 2, sample No. 1, it was difficult to divide along the dividing groove. However, the wiring board with the dividing groove of the present invention is thin, and even when a shallow dividing groove is formed, it can be easily divided, and there is no division failure. It was suppressed.

It is sectional drawing of the wiring board with a division | segmentation groove | channel of this invention. It is sectional drawing explaining the manufacturing method of the wiring board with a division | segmentation groove | channel of this invention. It is sectional drawing explaining the manufacturing method of the wiring board with a division | segmentation groove | channel of this invention. It is sectional drawing explaining the manufacturing method of the wiring board with a division | segmentation groove | channel of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wiring board 3 with a dividing groove ... 1st insulating layer 5 ... 2nd insulating layer 7 ... Dividing groove 9 ... Dividing area | region 11 ... Wiring board 13 ... Wiring board area | region

Claims (2)

A wiring substrate region comprising an insulating substrate composed of a sintered first insulating layer and a second insulating layer that starts shrinking at a higher temperature than the first insulating layer and is sintered, and a wiring layer has a dividing groove. A wiring substrate with divided grooves assembled through a plurality of formed divided regions, wherein the glass amount of the insulating layer in the divided region is larger than the glass amount of the insulating layer in the wiring substrate region Grooved wiring board. Of at least one surface of the first green sheet and the second green sheet having a higher shrinkage start temperature than the first green sheet, a glass paste or glass sheet containing glass powder is disposed on the surface to be a divided region after firing. A step of laminating the first green sheet and the second green sheet on which the glass paste or the glass sheet is disposed, and a divided groove on a surface which becomes a divided region after firing the laminated body And forming the glass component contained in the glass paste or the glass sheet by heat-treating the laminated body provided with the dividing groove, and the glass component softened by the glass powder is converted into the first green sheet. And a step of permeating into at least one of the second green sheets, and then the first group Method of producing segmented grooved wiring board, characterized by comprising a Nshito and step of sintering the second green sheet.

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