JP5142824B2 - Wiring board and manufacturing method thereof - Google Patents

Description

  The present invention relates to a wiring board including a plurality of glass ceramic insulating layers and through conductors manufactured by simultaneous firing and a manufacturing method thereof.

  Conventionally, a wiring board for mounting a semiconductor element or the like uses ceramics such as alumina as a material for forming an insulating base (a plurality of insulating layers), and a refractory metal such as tungsten as a material for forming a wiring. It was.

  In contrast, wiring can be formed by simultaneous firing with a low-resistance metal (for example, Cu, Ag or Au) having a lower melting point than tungsten, which is superior in that the dielectric constant is lower than that of alumina ceramics. Glass ceramics have been attracting attention as a material for forming an insulating substrate adapted to the demand for higher integration of circuits.

  A wiring board using glass ceramics as an insulating base (a plurality of glass ceramic insulating layers) is formed by mixing an organic binder or the like with a glass ceramic raw material containing glass powder such as borosilicate glass and crystalline filler, for example. After manufacturing the glass ceramic green sheet, through holes are formed in the glass ceramic green sheet, and the through holes are filled with a paste for a through conductor mixed with a metal powder and an organic binder. A conductor pattern is printed at a predetermined position on the sheet to form a wiring pattern. And after aligning and pressurizing and laminating a plurality of green sheets, the obtained laminate is heated in a humidified nitrogen atmosphere and subjected to a binder removal treatment (burning off the organic binder), followed by firing ( It is obtained by simultaneously firing a plurality of glass ceramic green sheets and a paste for through conductors.

  In the wiring board, along with the recent miniaturization, enlargement, and speeding up of silicon chips, the flip chip connection part on which the silicon chip is mounted is miniaturized and the number of terminals is increased, and the flip chip connection part is flattened. The demand for degree is also increasing.

In order to improve the flatness of the flip chip connection part in the wiring board, the softening point is 700 to 1000 ° C. with respect to the main component Cu as a copper metallized composition (conductor paste) for via-hole conductors (for through conductors). By containing the glass frit, the copper metallized composition filled in the via hole (paste for through conductor) and the glass ceramic porcelain (glass ceramic green sheet) can be fired simultaneously, and the shrinkage rate during the firing process ( It is known that a glass-ceramic wiring board can be obtained in which the sintering behavior) matches and the via-hole conductor does not protrude from the surface of the insulating substrate (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 11-16418

  Generally, an organic binder is included in the through conductor paste as in the case of the glass ceramic green sheet. And since the main baking temperature is 900-1000 degreeC for the wiring board which has a wiring layer which has Cu as a main component, and a penetration conductor, binder removal temperature is normally adjusted in the narrow temperature range of 700-800 degreeC.

  As described above, since the binder removal temperature is adjusted within a narrow temperature range, there is a problem in that the binder removal failure may occur due to poor adjustment. Specifically, if the gas generated by the combustion of the residual carbon is not sufficiently discharged to the outside, a cavity by this gas is formed inside the through conductor, and the through conductor is formed on the surface of the insulating substrate by the formation of this cavity. It is a problem that it protrudes from.

  Here, the gas generated by the combustion of residual carbon is not sufficiently discharged to the outside because the through conductor formed in the surface glass ceramic insulating layer and the through conductor formed in the inner glass ceramic insulating layer are sintered. This seems to be due to the difference in behavior at the time of ligation. That is, the through conductor paste formed in the surface layer and the through conductor paste formed in the inner layer have different amounts of heat applied during firing, so the through conductor paste formed in the surface layer is formed in the inner layer. Sintering starts before the paste, and when the through conductor paste formed on the surface layer is sintered, the through conductor paste formed on the inner layer is not yet completely sintered. In particular, when the thickness of the wiring board is thick, the debinding process is not completely completed within a predetermined holding time, and the residual carbon is burned (debinding process) even during the temperature increase of the main firing. Since the sintering is in progress, the binder removal treatment of the through conductor paste formed in the inner layer has not yet been completed even when the through conductor paste formed in the surface layer has been sintered. As a result, the gas generated thereby loses its place and lifts the through conductor formed on the surface layer.

  To cope with this problem, it is conceivable to set the debinding temperature to a low temperature (less than 700 ° C.) and extend the holding time at that temperature, but extending the holding time leads to a decrease in production efficiency. In particular, since the sintering start temperature of low resistance metals such as Cu and Ag is around 700 ° C., the longer the holding time in the low temperature range (below 700 ° C.), the better the binder removal efficiency, but the through conductor paste and glass Inconsistency in sintering behavior with the ceramic green sheet occurs. That is, even if a cavity is not formed inside the through conductor, there arises a problem that the through conductor largely protrudes from the surface of the insulating base due to this mismatch in sintering behavior.

  The present invention has been made in view of such circumstances, and provides a wiring board in which protrusion of the through conductor from the surface of the insulating base due to poor debinding and mismatched sintering behavior is suppressed, and a method for manufacturing the same. With the goal.

The present invention provides an insulating base formed by laminating three or more glass ceramic insulating layers, a wiring layer formed on the surface and inside of the insulating base, and a glass ceramic insulating layer constituting the inner layer. A wiring board comprising: a first through conductor; and a second through conductor formed in the glass ceramic insulating layer constituting the surface layer and directly connected to the first through conductor, The penetrating conductor and the second penetrating conductor contain the same amount of the same metal as a main component, and the first penetrating conductor further contains glass and does not substantially contain precipitated crystals. Furthermore, it contains glass and precipitated crystals.

The present invention also includes a glass powder and a metal powder that are formed with through-holes and that do not substantially crystallize after firing, and that do not contain glass powder that partially crystallizes after firing. A step of producing a first glass-ceramic green sheet filled with paste, a glass powder in which a through-hole is formed and partially crystallized after firing in the through-hole, and the same amount as the first through-conductor paste A second glass-ceramic green sheet filled with a second through-conductor paste containing metal powder, and arranging the first glass-ceramic green sheet in an inner layer and the second glass-ceramic A green sheet is arranged on the surface layer to produce a laminate in which the first through-conductor paste and the second through-conductor paste are directly connected. And that step is a method of manufacturing a wiring substrate characterized by having a step of firing the laminate.

  According to the wiring board of the present invention, the first through conductor formed in the glass ceramic insulating layer constituting the inner layer and the second through conductor formed in the glass ceramic insulating layer constituting the surface layer are mainly made of the same metal. The first through conductor further includes glass and does not substantially contain precipitated crystals, and the second through conductor further includes glass and precipitated crystals, so that the insulation of the second through conductor is included. A wiring board in which protrusion from the substrate surface is suppressed can be realized.

  Further, according to the method for manufacturing a wiring board of the present invention, the through-hole formed in the first glass ceramic green sheet disposed in the inner layer contains glass powder that does not crystallize substantially after firing, and partially after firing. Glass that is filled with the first paste for through conductors that does not contain glass powder that crystallizes, and partially crystallizes after firing in the through holes formed in the second glass ceramic green sheet disposed on the surface layer By filling the paste for the second through conductor containing powder, minute voids are formed by volume shrinkage when the glass powder in the second paste for through conductor is crystallized. This void serves as an escape path for the gas generated from the first paste for through conductor, and the protrusion of the second through conductor from the surface of the insulating base can be effectively suppressed.

  The voids formed in the second paste for penetrating conductors are almost eliminated by the subsequent holding (sintering) at the main firing temperature, so there is no risk of lowering the reliability due to the intrusion of moisture or the like.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view of an embodiment of a wiring board of the present invention.

  The wiring substrate shown in FIG. 1 includes an insulating substrate 1 formed by laminating a plurality of glass ceramic insulating layers 1a to 1i, a wiring layer 2 formed on and in the surface of the insulating substrate 1, and a glass ceramic insulation constituting an inner layer. A first through conductor 31 formed in the layers 1b to 1h and a second through conductor 32 formed in the glass ceramic insulating layers 1a and 1i constituting the surface layer and directly connected to the first through conductor 31. A wiring board provided.

  The insulating substrate 1 is composed of three or more glass ceramic insulating layers (in this example, nine glass ceramic insulating layers 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i), and a crystal phase and glass It is formed of a glass ceramic sintered body having a phase. For example, when a glass ceramic insulating layer having a high thermal expansion coefficient is desired, examples of the crystal phase include forsterite, enstatite, barium silicate, lithium silicate, sodium silicate, and the like. On the other hand, when a glass ceramic insulating layer having a low coefficient of thermal expansion is desired, examples of the crystal phase include cordierite, barium aluminosilicate, spodumene, anorthite, spinel, mullite and the like. This crystal phase may be precipitated from glass powder as a raw material, or may be mixed as a crystalline filler.

  A wiring layer 2 mainly composed of a low-resistance metal such as Cu or Ag is formed on the surface and inside of the insulating base 1, and differs depending on the first through conductor 31 or the second through conductor 32 described later. The wiring layer 2 provided in the layer and the wiring layer 2 are electrically connected.

  Of the plurality of glass ceramic insulating layers 1a to 1i, the first through conductor 31 is formed in the glass ceramic insulating layers 1b to 1h constituting the inner layer, and in the glass ceramic insulating layers 1a and 1i constituting the surface layer A second through conductor 32 that is directly connected to the first through conductor 31 is formed.

  Here, the first penetrating conductor 31 and the second penetrating conductor 32 are common in that they have the same metal (a low resistance metal such as Cu or Ag) as a main component, but are deposited from glass as described later. There is a difference in the presence or absence of crystals.

  The first through conductor 31 further contains glass and does not substantially contain precipitated crystals (crystals precipitated from glass powder as a raw material). In such a configuration, as the glass to be included in the first through conductor paste for forming the first through conductor 31, non-crystalline glass that does not substantially precipitate crystals after firing may be used. A crystalline glass that is partially crystallized later is not used. Therefore, the non-crystalline glass remains as it is in the glass state in the first through conductor 31 after firing, so that substantially no precipitated crystals from the glass are present. In addition, that a crystal | crystallization does not precipitate substantially means that it is the quantity of the grade which the peak derived from the crystal | crystallization is not recognized in X-ray diffraction.

  On the other hand, the second through conductor 32 further includes glass and precipitated crystals (crystals precipitated from glass powder as a raw material). In such a configuration, a crystalline glass that partially crystallizes after firing may be used as the glass contained in the second through conductor paste that becomes the second through conductor 32. Note that part of the crystalline glass contained in the second paste for through conductors is precipitated as crystals in the second through conductor after firing, and the remaining part remains as glass.

  As described above, the first through conductor 31 and the second through conductor 32 are different from each other in the presence or absence of precipitated crystals from the glass powder as a raw material, so that each through conductor is formed during firing. Thus, it is possible to obtain a wiring board in which protrusion of the penetrating conductor from the surface of the insulating substrate 1 due to poor debinding caused by the difference in the amount of heat applied to the through conductor paste is suppressed.

  Next, the manufacturing method of the wiring board of this invention is demonstrated.

  First, in order to form the insulating substrate 1, a glass ceramic green sheet is produced using only glass powder or a filler composed of glass powder and crystalline material. Specifically, this glass ceramic green sheet is prepared by adding a solvent, an organic binder for molding and the like to the above raw material powder and mixing to prepare a slurry, which is then treated by a doctor blade method, a calender roll method, a rolling method, etc. It can be formed by the method of.

  The structure of the starting material (glass powder alone or filler composed of glass powder and crystalline material) can be changed depending on the properties required for the glass ceramic insulating layer. That is, when a glass-ceramic insulating layer having a high coefficient of thermal expansion is desired, the glass has a crystal phase with a high coefficient of thermal expansion, such as forsterite, enstatite, barium silicate, lithium silicate, sodium silicate, etc., after firing. Use. Alternatively, a glass that does not precipitate a crystalline phase after firing can be used, and a crystalline filler having a high thermal expansion such as quartz, tridymite, forsterite, barium silicate, or garnite can also be used. In addition, when a glass ceramic insulating layer having a low coefficient of thermal expansion is desired, a glass in which a crystal phase having a low coefficient of thermal expansion such as cordierite, barium aluminosilicate, spodumene, anorthite, spinel, mullite is precipitated after firing, Similarly to glass, a crystalline phase having a low coefficient of thermal expansion can be used as a filler without precipitating a crystalline phase after firing.

Specifically, in addition to borosilicate glass such as borosilicate glass, zinc borosilicate glass and lead borosilicate glass containing alkaline earth oxide, lithium silicate glass and the like can be given. As the filler made of a crystalline material, oxides such as Al ₂ O ₃ , SiO ₂ , ZrO ₂ , CaO, MgO or MgO, or a composite oxide of two or more of these oxides can be used. By adjusting the blending ratio of glass powder and crystalline filler, the firing temperature of the glass ceramic sintered body is matched with the firing temperature of the paste for through conductors, or the strength of the glass ceramic sintered body itself is increased. Can do. It is effective that the ratio of the glass powder to the crystalline filler is, for example, 20:80 to 80:20 by volume.

  Next, a through hole is formed at a predetermined position of the obtained glass ceramic green sheet, and a through conductor paste is filled in the through hole. This through-conductor paste is obtained by adding glass powder, an organic binder, a solvent, a dispersant, and the like to a metal powder mainly composed of a low resistance metal such as Cu or Ag.

  Here, the through-conductor paste (first through-conductor paste) filled in the through-hole formed in the inner-layer glass-ceramic green sheet (first glass-ceramic green sheet) and the surface-layer glass-ceramic green sheet Different glass powder is used for the through-conductor paste (second through-conductor paste) filled in the through-holes formed in the (second glass ceramic green sheet).

  That is, as the glass powder used for the first paste for through conductors, glass powder made of amorphous glass that does not substantially crystallize after firing is used, and glass made of crystalline glass that partially crystallizes after firing. Do not use powder. According to this configuration, the sintering behavior of the first through conductor paste matches the sintering behavior of the first glass ceramic green sheet. The matching of the sintering behavior means that the sintering curve in the sintering curve draws a similar curve.

Specifically, it is preferable to use borosilicate glass containing SiO ₂ and B ₂ O ₃ as the glass powder, and various alkali metal oxides, alkaline earth metal oxides, for the purpose of adjusting the glass transition point, al ₂ O _3, ZnO or a material obtained by adding like ZrO ₂ are used, these blending ratio can be arbitrarily selected. The glass transition point is preferably 600 ° C. or higher so that the binder component contained in the paste for through conductors can be efficiently removed from the binder, and the glass transition point is 800 ° C. or lower in terms of densification of the through conductors. Is preferred. For example, amorphous glass (glass transition point 680 ° C.) comprising 45% by mass of SiO ₂ , 30% by mass of BaO, 10% by mass of B ₂ O ₃ , 10% by mass of Al ₂ O ₃ and 5% by mass of CaO. In which no crystal phase is precipitated after firing).

The amount of glass to be added is preferably 3 to 20 parts by mass with respect to 100 parts by mass of the metal powder, and for the purpose of adjusting the difference in sintering behavior between the first through-conductor paste and the first glass ceramic green sheet, Up to 2 parts by mass of a crystalline filler (for example, SiO ₂ or Al ₂ O ₃ ) can be added.

  In addition, as the glass powder used for the second paste for through conductor, glass powder made of crystalline glass that partially crystallizes after firing is used. According to this configuration, the matching between the sintering behavior of the second through-conductor paste and the sintering behavior of the second glass ceramic green sheet is the same as the first through-conductor paste and the first glass ceramic green sheet. Although not as good as the matching between the two, there is an effect to be described later on the debinding failure. That is, in the second paste for through conductors, it is more important to eliminate the problem that cavities are generated in the through conductors, rather than matching with the sintering behavior of the second glass ceramic green sheet. The second through-conductor paste may contain glass powder made of amorphous glass in addition to glass powder made of crystalline glass.

As the glass powder used for the second through conductor paste, it is preferable to use a borosilicate glass containing SiO ₂ and B ₂ O _{3 in the same} manner as the glass powder used in the first through conductor paste, This various alkali metal oxides, alkaline earth metal _oxides, those obtained by adding like Al ₂ O 3, ZnO or ZrO ₂ are used. The glass transition point is preferably 600 to 800 ° C. like the glass powder used for the first through conductor paste, but the difference is that the crystal phase is precipitated after firing. Whether or not the crystal phase is precipitated after firing is determined by using an appropriate composition using various glass databases. Alkali metal oxide, alkaline earth metal oxide and SiO ₂ , or alkali metal oxide Or an alkaline earth metal oxide and SiO ₂ , Al ₂ O ₃ are close to the stoichiometric composition, and a composition in which B ₂ O ₃ and other components are externally added thereto can easily precipitate a crystal phase. . For example, glass composed of 45% by mass of SiO ₂ , 30% by mass of Al ₂ O ₃ , 10% by mass of MgO, 10% by mass of B ₂ O ₃ , and 5% by mass of ZnO (glass transition point 720 ° C. after firing) And cordierite and garnite are precipitated).

The amount of glass to be added is preferably 3 to 20 parts by mass with respect to 100 parts by mass of the metal powder, and for the purpose of adjusting the difference in sintering behavior between the second through-conductor paste and the second glass ceramic green sheet, Up to 2 parts by mass of a crystalline filler (for example, SiO ₂ or Al ₂ O ₃ ) can be added.

Whether the glass is a crystalline glass or an amorphous glass (whether or not crystals are precipitated after firing) is related to the constituent components of the glass. Specifically, when the amount of SiO ₂ or B ₂ O ₃ is increased, crystals tend not to precipitate after firing, and the amount of alkali metal, alkaline earth metal, Al ₂ O ₃ , ZrO ₂ or the like is large. If it becomes, it exists in the tendency for a crystal | crystallization to precipitate easily after baking. In particular, when a part of the composition constituting the glass has a stoichiometric composition ratio, crystals are likely to precipitate.

  Further, in order to obtain the effect of the present invention more remarkably, the glass transition point and the crystallization point of the glass powder contained in the second through conductor paste are the glass of the glass powder contained in the first through conductor paste. It is preferable that the glass amount is higher than the transition point or the glass amount contained in the second through conductor paste is larger than the glass amount contained in the first through conductor paste.

  Next, in order to form a wiring layer on the surface of the glass ceramic green sheet, a conductor paste containing a metal powder mainly composed of a low resistance metal such as Cu or Ag and a glass powder is screen printed in a circuit pattern. And printing by the gravure printing method. In addition, 1-10 mass parts of glass powder is added to 100 mass parts of metal powders in this conductor paste. This glass powder may be either crystalline or non-crystalline.

  Then, the glass ceramic green sheet formed as described above is laminated so that the first glass ceramic green sheet is arranged in the inner layer and the second glass ceramic green sheet is arranged in the surface layer, and the laminated body Is made. At this time, the first through-conductor paste and the second through-conductor paste are laminated so as to be directly connected.

  Finally, the laminate was held in humidified nitrogen at a temperature of 600 to 700 ° C. for several hours to perform a binder removal treatment, followed by main firing at a temperature of 850 to 1050 ° C. in the same atmosphere. The wiring board of the present invention is produced by simultaneously firing the sheet, the paste for through conductors, and the conductor paste.

  Preferably, for the purpose of preventing oxidation of the wiring layer 2 on the surface, a metal plating layer of Ni, Au, Cu or the like is formed to a thickness of 1 to 10 μm on the surface after firing by a technique such as electrolytic plating or electroless plating. It is formed.

  Here, the mechanism of debinding failure occurrence and its suppression will be described in detail.

  Since the glass powder which consists of non-crystalline glass which does not crystallize substantially after baking is used for the 1st through-conductor paste used as the 1st through-conductor 31 after baking, glass with a raise of baking temperature is used. With the softening of the first through conductor paste, sintering (firing shrinkage) starts. At this time, since the glass does not crystallize, it has a function of relieving stress due to a difference in sintering behavior between the first through-conductor paste and the glass ceramic green sheet, and can obtain very good consistency of the sintering behavior. it can.

However, when glass powder made of amorphous glass is used, with the softening of the glass, there is a tendency to take in residual carbon that could not be scattered during the debinding process, and these are in some form during the main firing. When exposed to carbon dioxide, there is a problem that CO ₂ gas is generated due to combustion of residual carbon.

  On the other hand, as described above, glass powder made of crystalline glass in which a part of the glass crystallizes after firing is used for the second through conductor paste that becomes the second through conductor 32 after firing. Here, the second through-conductor paste exhibits the same sintering behavior as the first through-conductor paste until crystals are precipitated, but the glass contained in the second through-conductor paste during the sintering. As a result of the crystal precipitation, the sintering behavior is different from the sintering behavior of the first paste for through conductors.

That is, when a part of the glass contained in the second through-conductor paste is crystallized, the sintering curve of the second through-conductor paste becomes gentler than that in the first through-conductor paste ( Burnt worse). In addition, density changes occur when crystals are precipitated from the glass. When a crystal composed of an element having a higher molecular weight than SiO ₂ or B ₂ O ₃ which is a main component constituting glass is precipitated, the density of the precipitated crystal becomes higher. Due to this density change, minute voids are formed around the precipitated crystals. The minute gap functions as a vent and plays a role of suppressing a debinding failure.

  Therefore, in the wiring board of the present invention, even if the above gas is generated from the first through conductor paste, the gas is generated by the minute gaps formed in the second through conductor paste. As a result, the second through conductor 42 can be prevented from protruding from the surface of the insulating base 1 as shown in FIG. In particular, in a wiring board having a thickness exceeding 2 mm, the effect of suppressing protrusion due to this debinding defect becomes remarkable.

  Thus, according to the manufacturing method of the wiring board of this invention, a micro space | gap is formed by the volume contraction at the time of the glass powder in the 2nd paste for through conductors crystallizing. This void serves as an escape path for the gas generated from the first paste for through conductor, and the protrusion of the second through conductor from the surface of the insulating base can be effectively suppressed. The first through-conductor paste contains glass powder made of non-crystalline glass but does not contain glass powder made of crystalline glass, so the through-conductor paste and the glass ceramic green sheet The inconsistency of the sintering behavior is suppressed as much as possible.

  The wiring board manufactured as described above has a very excellent flatness, and can be efficiently mounted when an electronic component such as a silicon chip is mounted.

  The evaluation board | substrate which evaluates the effect of this invention was produced as follows. This evaluation substrate is a laminate of 24 glass ceramic insulating layers having a width of 50 mm × 50 mm and a thickness of 2.4 mm. A through conductor having a diameter of 60 μm is arranged in the center of the substrate with 110 rows × 110 columns at intervals of 180 μm. A total of 12100 are arranged, and a land having a diameter of 90 μm is formed on each through conductor. The manufacturing method is shown below.

First, a glass ceramic green sheet to be a glass ceramic insulating layer was produced. 41 parts by mass of SiO ₂ , 20 parts by mass of MgO, 20 parts by mass of BaO, 8 parts by mass of Al ₂ O ₃ , 7 parts by mass of B ₂ O ₃ , ₂ parts by mass of CaO, 1 part by mass of SrO and ZrO A glass powder containing 1 part by mass of ₂ and a quartz powder are prepared, and these are weighed as 60% by mass of glass powder and 40% by mass of quartz powder, and acrylic resin as an organic binder, dioctyl phthalate as a plasticizer, and solvent A slurry prepared by adding toluene was molded by a doctor blade method to produce a glass ceramic green sheet having a thickness of 200 mm SQ and a thickness of 125 μm.

  Then, a through hole having a diameter of 70 μm was provided in the glass ceramic green sheet by punching.

  Next, first and second through conductor pastes were produced. The first through conductor paste is used for the first glass ceramic green sheet disposed in the inner layer, and the second through conductor paste is used in the second glass ceramic green sheet disposed in the surface layer. Is. 12 parts by mass of glass powder made of crystalline glass or amorphous glass having the composition shown in Table 1 is added to 100 parts by mass of Cu powder, and an acrylic resin as an organic binder and a mixed solution of terpineol and dibutyl phthalate as a solvent ( 80:20) by mass ratio was added and kneaded to prepare first and second through conductor pastes. Then, the two kinds of through-conductor pastes thus prepared were filled in the through holes provided earlier by screen printing.

  Subsequently, a conductor paste for a wiring layer was produced. Specifically, Cu powder and glass powder are prepared, acrylic resin is added as an organic binder to these powders, and a mixed solution of terpineol and dibutyl phthalate (80:20 by mass) is added and kneaded. Thus, a conductor paste for a wiring layer was produced. Then, the obtained wiring layer conductor paste was printed by a screen printing method as a land having a pattern with a diameter of 105 μm immediately above the through conductor paste.

  A laminated body was produced using the glass ceramic green sheet with the conductor paste thus obtained. The first glass ceramic green sheets were arranged one by one on the upper and lower sides (surface layer), and 22 second glass ceramic green sheets were arranged on the inner layer, and pressure lamination was performed at 45 ° C. and 4 MPa.

Subsequently, the laminate is placed on an Al ₂ O ₃ base plate and subjected to heat treatment at 700 ° C. in a humidified nitrogen atmosphere in order to decompose and remove organic components such as an organic binder. Firing was performed in the same atmosphere at 900 ° C. for 1 hour.

  The obtained substrate was subjected to electroless Ni plating and Au plating to obtain an evaluation substrate.

  Next, an evaluation method for the evaluation board will be described.

  First, in order to investigate whether or not the penetrating conductor protrudes from the surface of the insulating substrate due to a defective binder, the penetrating conductor formed on the surface glass ceramic insulating layer was observed with a 20 × optical microscope. Quantity was measured. Further, using a three-dimensional measuring machine, the distance from the edge portion of the through conductor to the longest portion at the center of the through conductor was measured as a protrusion amount, and a protrusion having a protrusion amount of 5 μm or more was regarded as defective. As for the judgment, with respect to 100 evaluation boards, the number of protrusions exceeding 5 μm is judged to be defective when one of the evaluation boards is one, and the case where the occurrence rate exceeds 0% is judged as NG. did. The results are shown in Table 2.

  Then, in order to examine whether or not the through conductors protrude from the surface of the insulating base due to mismatching of the sintering behavior between the paste for through conductors and the glass ceramic green sheet, 10 points per evaluation board with a three-dimensional measuring machine The amount of protrusion was measured. In the measurement, any two adjacent through conductors were selected, and the distance from the surface of the insulating substrate located between the two through conductors to the line segment connecting the vertices of the two through conductors was defined as the protrusion amount. This measurement method is a measurement method in the case where the through conductor protrudes from the surface of the insulating substrate. However, even when the through conductor is depressed, the measurement is performed with the same idea, and the value is displayed as a minus value. As a judgment, a case where the absolute value of the protrusion amount exceeds 5 μm was judged as NG. The results are shown in Table 2.

  Further, in order to confirm whether or not the crystal phase is precipitated from the glass added to the first and second through conductor pastes, the crystal phase is identified by X-ray diffraction in the first and second through conductors. Went. The results are shown in Table 2. Although not shown in Table 2, the amorphous glass contained in the through-conductor paste remains almost as glass in the fired through-conductor, and the crystalline glass contained in the through-conductor paste remains after firing. A part of the through conductor is precipitated as crystals, and the remaining part remains as glass.

  As is apparent from Table 2, sample No. which is a sample outside the scope of the present invention. Nos. 1 to 8 are obtained by adding glass that does not crystallize to the second through-conductor paste, but due to the faster sinterability of the second through-conductor paste, debinding failure occurred and the result It can be seen that the second through conductor protrudes in a partially explosive shape.

  In addition, sample No. which is a sample outside the scope of the present invention. Nos. 11, 12, 15, and 16 are obtained by adding glass that crystallizes both the first through-conductor paste and the second through-conductor paste. It is clear from the fact that there is no protrusion due to poor debinding due to the generation of voids due to the crystallization of glass, but there is no protrusion due to defective debinding. You can see that it is not.

  On the other hand, sample No. which is a sample within the scope of the present invention. As for 9, 10, 13, and 14, there is no protrusion due to defective debinding, and the protrusion due to mismatch in sintering behavior can be suppressed to less than 5 μm, and the flatness is excellent. I understand that.

It is a schematic sectional drawing of one Embodiment of the wiring board of this invention. It is a schematic sectional drawing of the wiring board as a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulation base | substrate 1a-1i Glass ceramic insulation layer 2 Wiring layer 31 1st penetration conductor 32 2nd penetration conductor

Claims (2)

An insulating substrate formed by laminating three or more glass ceramic insulating layers, a wiring layer formed on and inside the insulating substrate, and a first through conductor formed in the glass ceramic insulating layer constituting the inner layer And a wiring substrate comprising a second through conductor formed on the glass ceramic insulating layer constituting the surface layer and directly connected to the first through conductor,
The first penetrating conductor and the second penetrating conductor contain the same amount of the same metal as a main component, and the first penetrating conductor further contains glass and does not substantially contain precipitated crystals, The through-hole conductor further includes glass and precipitated crystals. Through hole is formed, comprising a glass powder and metal powder does not substantially crystallize after firing through hole, the first via conductor paste portion after firing does not contain glass powder to crystallize is filled Producing a first glass ceramic green sheet;
A through-hole is formed, and a second through-conductor paste containing a glass powder partially crystallized after firing and the same amount of metal powder as the first through-conductor paste is filled in the through-hole. Producing a glass ceramic green sheet of 2;
The first glass ceramic green sheet is disposed in an inner layer and the second glass ceramic green sheet is disposed in a surface layer so that the first through-conductor paste and the second through-conductor paste are directly Producing a laminated body laminated so as to be connected;
And a step of firing the laminated body.

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