JP2011165945A - Multilayer ceramic substrate and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer ceramic substrate, capable of suppressing the occurrence of cracks near an interlayer connecting conductor section, preventing the destruction of a substrate, and enhancing the bonding strength of a protruding member, and to provide a method for producing the substrate. <P>SOLUTION: The distance Z between the circumscribed circle of a brazing material layer 59, in the circumference of the bottom surface of a stud 23 and the area center of a via 55 disposed around a surface metal layer 57 on the top-surface low-temperature baking ceramic layer, is not less than 2.5 mm. Centered about the area center of the bottom surface of the stud 23, the difference (ML-RL) between the radial length ML of the surface metal layer 57 and the same radial length RL of the bottom surface of the brazing material layer 59 is not less than 0.65 mm, all around the circumference of the stud 23. Centered about the area center of the bottom surface of the stud 23, the ratio (VL/SL) between a radial length VL up to the area center of a via 55 closest to the stud 23 and the same radial length SL of the bottom surface of the stud 23 is from 1.6 to 2.0. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a multilayer ceramic substrate using a low-temperature fired ceramic as a ceramic and having a low-resistance conductor therein and a method for manufacturing the same. Specifically, the present invention relates to a multilayer ceramic substrate and a method of manufacturing the same that can provide connection strength that can maintain sufficient connection reliability when a metal protruding member is bonded to the substrate surface via a brazing material layer. is there.

  This multilayer ceramic substrate is used as an inspection substrate for inspecting electronic components, IC packages, ICs on wafers, for example. For example, a semiconductor element inspection substrate provided with a protruding member protruding from the substrate surface to be attached to the semiconductor element inspection apparatus can be mentioned.

In recent years, there has been an increasing demand for ceramic substrates for various uses, such as improvement of dimensional accuracy and enlargement (reducing the number of steps by arranging a large number of small parts).
Also, in some applications, in order to form a pattern with higher accuracy, a thin film or thick film conductor is formed on the surface of the substrate after firing to ensure the positional accuracy with the IC and other components to be connected. ing.

  Therefore, in the future, it is expected that the formation of a highly integrated and fine surface layer conductor pattern will be required, and in that case, it becomes important to further improve the dimensional accuracy of the substrate itself after firing.

  As a method for achieving this high dimensional accuracy, the non-shrinkage firing method is effective, and the non-shrinkage firing method is substantially free from shrinkage in the planar direction, and therefore, the dimensional variation during firing can be extremely reduced. There is a merit.

  As the non-shrinkage firing method, a second green sheet formed of a material that does not sinter at a temperature for firing the green sheet laminate is laminated on the upper and lower surfaces of the green sheet laminate in which the first green sheets are laminated. Thus, during firing, the second green sheet suppresses contraction in the plane direction (XY direction) when the green sheet laminate contracts, thereby realizing high dimensional accuracy (ie, high dimensional accuracy multilayer ceramic). A method for manufacturing a substrate) is known.

  In this non-shrinkage firing method, a low-temperature fired ceramic that can be fired at a lower temperature than the material forming the second green sheet is used as the ceramic material of the multilayer ceramic substrate. As the conductive material to be configured, a low resistance conductor such as Ag having a low melting point capable of simultaneous firing is used.

  As described above, the low-temperature fired ceramic material is, for example, a material that can be sintered at a temperature lower than that of alumina (for example, 1050 ° C. or lower), and is generally composed of glass and filler. A multilayer ceramic substrate using this low-temperature fired ceramic material tends to have a lower mechanical strength because it contains more glass than the multilayer ceramic substrate made of alumina.

  For this reason, in a multilayer ceramic substrate made of alumina, when joining a metal member such as a stud to the surface, sufficient joining strength can be generally obtained by joining using a brazing material. In the case of the multilayer ceramic substrate, since the mechanical strength is low, it is difficult to obtain sufficient bonding strength.

  As a countermeasure against this, it is conceivable to minimize the tensile stress generated in the portion where the metal member and the multilayer ceramic substrate are joined, and various studies have been made so far (see Patent Documents 1 to 3 below).

  For example, Patent Document 1 discloses a technique for improving the bonding strength of a metal member by dispersing the stress applied to the bonded portion by covering with a protective layer including the brazing material portion used for bonding the metal member. Yes.

Patent Document 2 discloses a technique for improving the bonding strength of a metal member by embedding a thick film pad for arranging input / output pins, which are metal members, in the ceramic.
Furthermore, Patent Document 3 discloses a technique for reducing stress generated during joining of metal members by providing a stress relaxation layer made of a circular metal layer between a signal pin, which is a metal member, and a wiring conductor. Yes.

Japanese Patent Laid-Open No. 1-235687 JP-A-9-18144 JP-A-8-172273

  However, as a result of research by the present inventors, in a multilayer ceramic substrate using a low-temperature fired ceramic material, due to the difference in thermal expansion characteristics between the low-temperature fired ceramic material and the low-resistance conductor, metal members (particularly the substrate) It has been found that the bonding strength at the time of bonding a protruding member protruding from the surface is lowered, and the above-described conventional technique does not have sufficient countermeasures.

  That is, as illustrated in FIG. 7, a multilayer ceramic substrate (P1) using a low-temperature fired ceramic material has, for example, a via made of a metal material (interlayer connection conductor portion: P2), an electrode layer (P3), and a surface metal layer. (P4), protruding members such as studs (P5), and brazing material layers (P6) are formed. What is the thermal expansion coefficient (CTE) of these metal materials and the thermal expansion coefficient of low-temperature fired ceramic materials? Since they differ greatly, there is a problem that cracks are generated especially around the vias.

  Specifically, first, the thermal expansion coefficient of Ag or Cu constituting the via is about 15 to 19 ppm / ° C., and the thermal expansion coefficient of the low-temperature fired ceramic is about 4 to 7 ppm / ° C. Due to the large difference in the coefficients, a large residual stress is generated around the via after co-firing of the substrate. Thereafter, when brazing the protruding member on the surface metal layer, Au / Sn or the like having a thermal expansion coefficient of 10 ppm / ° C. or more is used as the brazing material (which is greatly different from the thermal expansion coefficient of the low-temperature fired ceramic). Along with cooling, a large residual stress is generated around the brazing material.

  As a result, a large residual stress is generated around the protruding member. When a large external force is applied to the protruding member, a crack is generated especially around the via, and the substrate is destroyed starting from the crack. Therefore, there is a problem that the bonding strength (connection strength) of the protruding member is lowered.

  The present invention has been made to solve the above-described problems, and suppresses the occurrence of cracks in the vicinity of the interlayer connection conductor portion around the protruding member, prevents the substrate from being broken, and An object of the present invention is to provide a multilayer ceramic substrate capable of increasing the bonding strength and a method for manufacturing the same.

  (1) The invention of claim 1 has a plurality of low-temperature fired ceramic layers made of low-temperature fired ceramics, has an internal conductor layer made of a low-resistance conductor and an interlayer connection conductor part inside, and at least the thickness direction A multilayer ceramic substrate having a surface metal layer on one surface and a protruding member that protrudes from the substrate surface via a brazing material layer on the surface metal layer, the multilayer ceramic substrate having a thickness When viewed in the direction, (A) the circumscribed circle of the brazing material layer on the outer periphery of the bottom surface of the projecting member, and the interlayer connection conductor disposed around the surface metal layer in the outermost low-temperature fired ceramic layer The distance Z between the center of the area of the portion is 2.5 mm or more, and (B) the length ML in the radial direction of the surface metal layer around the center of the area of the bottom surface of the protruding member; Material layer The difference (ML−RL) from the length RL in the same radial direction of the bottom surface is 0.65 mm or more over the entire outer periphery of the bottom surface of the protruding member, and (C) the center of the area of the bottom surface of the protruding member is centered The ratio (VL / SL) of the length VL in the radial direction to the center of the area of the interlayer connection conductor portion closest to the protruding member and the length SL in the same radial direction of the bottom surface of the protruding member is 1 .6 to 2.0.

  In the present invention, as is clear from the experimental examples described later, (A) the distance Z between the circumscribed circle of the brazing material layer and the area center of the interlayer connection conductor portion around the surface metal layer is 2.5 mm or more. (B) Since the difference (ML−RL) between the length ML in the radial direction of the surface metal layer and the length RL in the same radial direction of the bottom surface of the brazing material layer is 0.65 mm or more over the entire circumference. (C) The ratio (VL / SL) between the length VL in the radial direction to the center of the area of the interlayer connection conductor portion closest to the protruding member and the length SL in the same radial direction of the bottom surface of the protruding member is 1.6. Even when a large external force is applied to the protruding member in the configuration of ~ 2.0 (that is, when the thickness of the protruding member is larger than that of the pin or the like), there is a crack in the vicinity of the interlayer connection conductor around the protruding member. It is possible to suppress the occurrence and prevent the substrate from being destroyed.That is, the joint strength (connection strength) of the protruding member can be increased.

  Specifically, the residual stress generated when the projecting member is brazed when the interlayer connection conductor is disposed at a position closer than 2.5 mm, not the “distance Z is 2.5 mm or more” in the condition (A). (Tensile stress) may be greater than the bonding strength between the low-temperature fired ceramic layer and the interlayer connection conductor near the interlayer connection conductor. For this reason, when an external force is applied to the protruding member, a crack may occur at the interface between the low-temperature fired ceramic layer and the interlayer connection conductor, and the substrate may be destroyed starting from the crack. Therefore, it is necessary to set the distance Z in the present invention.

  Further, if “ML-RL is 0.65 mm or more over the entire circumference” in the condition (B), the stress generated at the end of the brazing material is relaxed in the surface metal layer during the cooling stage in the brazing process. By doing so, the bonding strength (adhesion strength) of the protruding member can be sufficiently ensured.

  Therefore, in the present invention, a high bonding strength can be realized not only in a thin protruding member such as a pin but also in a member having a large diameter such as a stud, such as “VL / SL is 5 or more”.

  (2) The invention of claim 2 is characterized in that the difference in linear thermal expansion coefficient between the low-temperature fired ceramic and the low-resistance conductor in the range of room temperature (30 ° C.) to 350 ° C. is 12 ppm / ° C. or more. And

  The present invention exemplifies the difference in the linear thermal expansion coefficient between the low-temperature fired ceramic and the low resistance conductor. When the difference in the thermal expansion coefficient is as large as 12 ppm / ° C. or more, the large residual stress described above is used. Therefore, the effect of preventing the occurrence of cracks of the present invention is remarkably exhibited.

  (3) In the invention of claim 3, the low resistance conductor is one of Ag, Au, Cu, or a combination of at least two of Ag, Au, Cu, Pt, Pd, W, or It is characterized by being alloyed.

The present invention exemplifies a low resistance conductor.
(4) The invention of claim 4 is the method for producing a multilayer ceramic substrate according to any one of claims 1 to 3, wherein a step of producing a first green sheet made of the low-temperature fired ceramic material; A step of forming a through hole in order to form the interlayer connection conductor portion at a predetermined location of the first green sheet; and filling the through hole with a conductive paste containing the low resistance conductor; A step of applying a conductor paste including a low-resistance conductor to form the inner conductor layer at a predetermined location on the surface of one green sheet; and a plurality of first green sheets filled and applied with the conductor paste. A step of laminating to form a green sheet laminate, and a material that does not sinter at the temperature at which the first green sheet sinters on both sides in the thickness direction of the green sheet laminate. A step of laminating the second green sheet to form a composite green sheet laminate, a step of firing the degreased and pressurized composite green sheet laminate, and a step of forming the second green sheet after the firing. Removing the sintered layer, polishing the surface of the sintered body after removing the unsintered layer, forming the surface metal layer on the surface of the sintered body after polishing, And a step of brazing the protruding member on the surface metal layer.

According to the present invention, the multilayer ceramic substrate according to any one of claims 1 to 3 can be easily manufactured.
Specifically, in the present invention, the shrinkage in the planar direction of the green sheet laminate made of the low-temperature fired ceramic is suppressed only in the thickness direction by the second green sheet during firing. Thus, when shrinkage occurs in only one direction, stress is applied to the interface between the low-temperature fired ceramic and the interlayer connection conductor due to the difference in shrinkage behavior between the low-temperature fired ceramic and the low-resistance conductor interlayer connection conductor. Furthermore, stress is applied also when the protruding member is brazed. However, when the multilayer ceramic substrate having the above-described configurations (A) to (B) is manufactured by the manufacturing method of the present invention, the substrate (even when a large external force is applied to the protruding member after brazing). Can be easily manufactured.

In addition to the surface metal layer to which the protruding member is bonded, for example, a surface conductor layer (electrode layer) that is electrically connected to the interlayer connection conductive portion may be formed on the surface of the sintered body.
The configuration of the invention of each claim will be described below.

  The low-temperature fired ceramic is a ceramic that can be sintered at a low temperature of 1050 ° C. or lower. For example, a low-temperature fired ceramic (glass ceramic) having a composition of borosilicate glass and alumina (or mullite) can be employed.

  Moreover, it is preferable that the low-temperature fired ceramic has a bending strength of 150 MPa or more and 320 MPa or less. In particular, when the bending strength is lower than 150 MPa, even a ceramic alone may not be able to obtain sufficient strength due to a defect in the ceramic substrate due to the stress generated by brazing. In addition, when the bending strength exceeds 320 MPa, sufficient strength can be obtained regardless of the structure and design. However, in a low-temperature fired ceramic having a low resistance conductor, in order to obtain such high strength, The characteristics may be limited. For example, when a low thermal expansion coefficient is required as in the case of a semiconductor element inspection substrate, the required thermal expansion coefficient may not be obtained.

  Furthermore, the Young's modulus of the low-temperature fired ceramic is preferably 50 GPa or more and 150 GPa or less. For example, when a multilayer ceramic substrate is used as a semiconductor element inspection substrate, it is necessary to adjust the flatness of the substrate surface in order to bring the inspection probe into uniform contact with the Si wafer to be inspected. Is also used to adjust the substrate surface by pushing or pulling the substrate when adjusting its flatness. For that purpose, the Young's modulus of the low-temperature fired ceramic to be joined to the protruding member is important.

  When the Young's modulus exceeds 150 GPa, the force necessary for flattening the substrate becomes too strong, and it is possible to obtain a sufficient bonding strength of the protruding member against the stress applied to adjust the flatness. It can be difficult. On the other hand, when the Young's modulus is less than 50 MPa, when the substrate is used as a semiconductor element inspection substrate, the substrate is deformed by the force of pressing the probe against the wafer, so that uniform contact may be difficult.

  The low-resistance conductor is a conductor that can be simultaneously fired (sintered) when firing the low-temperature fired ceramic. Specifically, it has a low melting point (for example, a melting point of 1000 ° C. or less) and a low resistance value (for example, a specific resistance) Is a conductor of 2 to 4 μΩ · cm or less, and a conductor such as Ag, Ag—Pd, Ag—Pt, Au, or Cu can be used as described later.

The inner conductor layer is a conductive layer formed between the low-temperature fired ceramic layers.
The interlayer connection conductor portion is a conductor portion (for example, a via) that electrically connects an inner conductor layer or an inner conductor layer and a surface conductor layer (for example, an electrode pad).

  The material of the surface metal layer (to which the protruding member is bonded) is a suitable combination of Ti and Cr for the ceramic bonding surface, Cu, Pd, Mo and Ni for the intermediate layer, and Au for the outermost surface layer. Can be adopted. As the surface metal layer, a thin film conductor formed by vapor deposition, sputtering, or the like can be used.

-As a material of the brazing material constituting the brazing material layer, Au-based (for example, Au-Sn-based), Ag-based (for example, Ag-Cu-based) material, and the like are suitable.
When the protruding member is joined at a relatively low temperature such as solder, the stress due to the difference in thermal expansion coefficient between the low-temperature fired ceramic and the interlayer connection conductor portion made of a low-resistance conductor is not enhanced, but Au When using a brazing material such as Au / Sn, Au / Ge, or Au / Si or an Ag-based brazing material (such as Ag / Cu, Ag / Cu / Sn, or Ag / Cu / In) Since the bonding temperature of these brazing materials (300 to 400 ° C. for Au and 600 to 800 ° C. for Ag) becomes high, in addition to the stress generated during firing, When a further stress is generated during cooling, the interface between the low-temperature fired ceramic and the interlayer connection conductor portion made of a low-resistance conductor is likely to be broken. Therefore, the configuration of the present invention is effective.

  The protruding member is a member that is bonded to the surface of the multilayer ceramic substrate and protrudes outward (for example, perpendicularly) from the surface, and a metal such as Kovar can be used as the material. Moreover, as the shape, a columnar (cylindrical) member having a circular bottom surface can be employed.

  Further, the projecting member is not limited to a member having the same cross-sectional shape or diameter (perpendicular to the axis) along the axial direction, and a member having a different cross-sectional shape or diameter along the axial direction can be adopted. For example, it is composed of, for example, a disk-shaped large-diameter portion joined to a multilayer ceramic substrate, and a cylindrical-shaped (smaller diameter than the large-diameter portion) projecting from the large-diameter portion (away from the substrate). Configuration can be adopted.

In particular, according to the present invention, the area of the bottom surface of the large-diameter portion is 60 to 110 mm ² (diameter 8.7 to 12 mm in the case of a disk), and the cross-sectional area (perpendicular to the axis) of the small-diameter portion is 7 to ²⁰ mm ² In this case, a large effect can be obtained when a projecting member having a size is joined to the multilayer ceramic substrate as in the range of 3 to 5 mm in diameter.

  The projecting member preferably has a linear thermal expansion coefficient of 9 ppm / ° C. or less in the range of room temperature (30 ° C.) to 350 ° C. This is because the linear thermal expansion coefficient in the range from room temperature to 350 ° C. of the low-temperature fired ceramic material used is, for example, about 4 to 8 ppm / ° C., so that the above range is reduced from the viewpoint of reducing the difference in thermal expansion coefficient. This is because a degree not greatly exceeding is preferable.

  The radial direction is a direction extending outward from a central axis passing through the center of the area (perpendicular to the substrate surface) at a right angle (thus parallel to the substrate surface), and when the bottom surface of the projecting member is a circle, That is the radial direction.

It is explanatory drawing which fractures | ruptures and shows the board | substrate for a semiconductor element test | inspection and board | substrate holding | maintenance apparatus of 1st Example. It is a top view of the board | substrate for semiconductor element inspection. It is explanatory drawing which fractures | ruptures and shows a part of substrate for a semiconductor element test | inspection in the thickness direction. It is explanatory drawing which expands and shows the plane of the surface metal layer periphery (in the range of the broken line of FIG. 3) of the board | substrate for semiconductor element inspection. It is explanatory drawing which fractures | ruptures and expands and shows the principal part of the board | substrate for a semiconductor element test | inspection in the thickness direction. It is explanatory drawing which shows the manufacturing process of the board | substrate for semiconductor element inspection. It is explanatory drawing of a prior art.

Embodiments of the present invention will be described below with reference to the drawings.
Here, description will be made based on an example in which the multilayer ceramic substrate of the present invention is applied to a semiconductor element inspection substrate.

a) First, a semiconductor element inspection substrate of this embodiment and a substrate holding apparatus for fixing the substrate will be described with reference to FIG.
As shown in FIG. 1, the semiconductor element inspection substrate 1 of this embodiment is used by being fixed to a substrate holding device 3 when performing electrical inspection of a silicon wafer (not shown) which is one of the semiconductor elements. It is what is done.

  In the substrate holding device 3, a wiring board 7 is laminated on a drive board 5 which is a reinforcing plate, and a square frame 9 is attached around the lower side of the wiring board 7.

On the other hand, the semiconductor element testing substrate 1 is disposed on the lower surface side of the wiring board 7 in the frame 9 via a plate-shaped interposer 11.
Contact terminals (probes) 13 that contact the silicon wafer are provided on the lower surface side of the semiconductor element inspection substrate 1, and contact terminals 15 and 17 are provided on both sides of the interposer 11. The contact terminals 15 and 17 on each surface side of the interposer 11 are in contact with the wiring board 7 and the semiconductor element inspection substrate 1, respectively.

  Further, a cylindrical projecting member (stud) 23 having a large diameter portion 19 and a small diameter portion 21 which will be described in detail later is joined to the center of the semiconductor element inspection substrate 1. A cylindrical extension stud 29 having a large-diameter portion 25 and a small-diameter portion 27 is coupled by a screw structure. In other words, the stud 23 and the extension stud 29 are integrally coupled by screwing the screw portion 31 above the stud 23 and the screw hole 33 below the extension stud 29.

  The extension stud 29 is disposed so as to pass through a through hole 35 opened in the thickness direction at the center of the drive board 5 and the wiring board 7, and a nut 39 is screwed into the screw portion 37 above the extension stud 29. In addition, a tapered spring washer 43 that is in contact with the step portion 41 of the through hole 35 is fitted below the nut 39.

  That is, the through-hole 35 has a small diameter at the center thereof, and the upper surface of the large-diameter portion 25 of the extension stud 29 abuts on the lower side of the small-diameter portion 44 of the drive board 5. The spring washer 43 is in contact with the (step portion 41).

  Therefore, by tightening the nut 39, the extension stud 29 and the stud 23 (and hence the semiconductor element inspection substrate 1) are moved upward, whereby the semiconductor element inspection substrate 1 can be fixed to the drive board 5.

  The semiconductor element testing substrate 1 described above corresponds to, for example, a φ300 mm (12 inch) silicon wafer, and the contact terminal 13 contacts the terminal of the IC chip on the silicon wafer (before cutting out each IC chip). Thus, it is possible to inspect a large number of IC chips at a time.

b) Next, the semiconductor element inspection substrate 1 will be described in detail with reference to FIGS.
As shown in FIG. 2, the semiconductor element inspection substrate 1 mainly includes a rectangular plate-shaped multilayer ceramic substrate 45 having a length of 96.25 mm, a width of 91.17 mm, and a thickness of 4.45 mm. The stud 23 is brazed on one surface with a brazing material containing Au and Sn (or a brazing material containing Ag and Cu).

Of these, the multilayer ceramic substrate 45 has a structure in which a plurality of glass ceramic layers 47 are laminated in the thickness direction as shown in FIG.
The glass ceramic layer 47 is made of, for example, a low-temperature fired glass ceramic obtained by firing a mixture of a glass component and a ceramic component at a low temperature of, for example, about 800 to 1050 ° C. Specifically, each glass ceramic layer 47 (and hence the glass ceramic portion of the multilayer ceramic substrate 45) is made of a glass ceramic whose main component is mullite and borosilicate glass. In addition, the linear thermal expansion coefficient in room temperature (30 degreeC)-350 degreeC of this glass ceramic (mass ratio 1: 1 of mullite and borosilicate glass) is 4.3 ppm / degrees C, for example.

  In addition, a large number of surface conductor layers (electrodes) 49 and 51 are formed on both surfaces of the multilayer ceramic substrate 45, and internal conductors are formed inside the multilayer ceramic substrate 45 (specifically, boundary portions of the glass ceramic layers 47). A layer 53 is formed. Furthermore, a cylindrical interlayer connection conductor (via) extending in the thickness direction of the substrate so that the electrode 49 on the front surface and the electrode 51 on the back surface of the multilayer ceramic substrate 45 are electrically connected via the internal conductor layer 53. 55 is formed.

  The conductor constituting the inner conductor layer 53 and the via 55 is a conductor that can be fired simultaneously at a low temperature during firing of the glass ceramic, that is, a low melting point of 950 to 1100 ° C. and a specific resistance of 2 to 4 μΩ · A low resistance conductor of cm (low resistance conductor) is used. As this low resistance conductor, for example, Ag, an Ag / Pt alloy, an Ag / Pd alloy, or the like is used. In addition, the linear thermal expansion coefficient in room temperature (30 degreeC)-350 degreeC of this resistance resistance conductor (for example, Ag) is 18 ppm / degrees C, for example.

In addition, the electrodes 49 and 51 can be composed of Ti, Cr, Mo, Cu, Ni, Au, and a conductor combining them. In this embodiment, the electrodes 49 and 51 are formed of a Cu layer on the Ti layer, It has a multilayer structure (not shown) in which an Ni layer and an Au layer are sequentially formed. The contact terminal 13 (see FIG. 1) is connected to the exposed surface of the electrode 49.
Further, on the surface of the multilayer ceramic substrate 45, as shown in FIG. 3 and FIG. 4 (enlarged main part), a surface metal layer 57 is formed at the center and four corners of the substrate surface in addition to the numerous electrodes 49. The stud 23 is bonded to the surface of the central surface metal layer 57.

The surface metal layer 57 is a square pattern having a length of 13.47 mm and a width of 13.47 mm, and Ti / Cu / Ni / Au are sequentially laminated from the lower layer.
Further, as shown in FIG. 5, the stud 23, for example, an outer diameter of 9.66mm × thickness 1.0 mm, on a disc-shaped large-diameter portion 19 of the bottom area 73.351Mm ^2, for example, the outer diameter 3.7mm X It has a cylindrical structure in which a cylindrical small diameter portion 21 having a height of 5.4 mm is formed coaxially, and the outer periphery of the small diameter portion 21 is a screw portion 33. As a material of the stud 23, for example, Kovar can be adopted. The surface of the stud 23 is plated with Ni and Au in order to improve the wettability of the brazing material.

  The stud 23 is made of, for example, an Au—Sn brazing material on the surface metal layer 57 at the center of the multilayer ceramic substrate 45 so that the center (area center) of the surface metal layer 57 coincides with the center of the stud 23. It is joined by.

  That is, a brazing material layer 59 made of a brazing material is formed between the surface metal layer 57 and the stud 23, and the brazing material layer 59 is formed on the outer peripheral side of the large diameter portion 19 of the stud 23. Is forming.

Particularly in this embodiment, the conditions (A) to (C) shown in the first aspect are satisfied.
(Condition A) As shown in FIG. 4 and FIG. 5, the circumscribed circle of the brazing material layer 59 on the outer periphery of the bottom surface of the stud 23 (the circumscribed circle centered on OX) and the surface of the outermost low-temperature fired ceramic layer 47 The distance Z between the area center (OY) of the via 55 arranged around the metal layer 57 is 2.5 mm or more.

  (Condition B) As shown in FIGS. 4 and 5, the outer peripheral end of the fillet 61 is drawn inward from the outer peripheral end of the surface metal layer 57 over the entire outer periphery of the stud 23. That is, the difference (ML−) between the radial length ML of the surface metal layer 57 and the same radial length RL of the bottom surface of the brazing material layer 59 around the center of the area (OX) of the bottom surface of the stud 23. RL) is 0.65 mm or more over the entire outer periphery of the stud 23.

  (Condition C) As shown in FIG. 5, the length VL and the stud in the radial direction from the center (OX) of the bottom surface of the stud 23 to the area center (OY) of the via 55 closest to the stud 23 The ratio (VL / SL) with the length SL in the same radial direction of the bottom surface of 23 is in the range of 1.6 to 2.0 (for example, 1.767).

c) Next, the manufacturing method of the semiconductor element inspection substrate 1 will be described in detail with reference to FIG.
First, as a ceramic raw material powder, a borosilicate glass powder having an average particle size of 3 μm and a specific surface area of 2.0 m ² / g and containing SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ as main components, and an average particle A mullite powder having a diameter of 2 μm and a specific surface area of 3.0 m ² / g was prepared.

Furthermore, an acrylic binder and DOP (dioctyl phthalate) were prepared as a binder component and a plasticizer component during sheet molding.
Then, a borosilicate glass powder and a mullite powder were introduced into an alumina pot at a mass ratio of 50:50 in a total amount of 1000 g, and 120 g of an acrylic resin was added. Furthermore, a ceramic slurry was obtained by putting an amount of a solvent (MEK: methyl ethyl ketone) and a plasticizer (DOP) necessary for giving an appropriate slurry viscosity and sheet strength into the pot and mixing them for 3 hours.

  Using the obtained ceramic slurry, a first green sheet 71 (for each glass ceramic layer 47) (see FIG. 6A) having a thickness of 0.15 mm was produced by a doctor blade method.

In addition to the step of producing the first green sheet 71, in order to produce a constraining sheet (second green sheet 73), the ceramic raw material powder has an average particle size of 2 μm and a specific surface area of 1 m ² / g. An alumina powder was prepared.

Furthermore, an acrylic binder was prepared as a binder component during sheet formation, DOP as a plasticizer component, and MEK as a solvent.
In the same manner as the first green sheet 71, 1000 g of alumina powder and 120 g of acrylic resin are put into an alumina pot, and a necessary amount of solvent (MEK) is added to give slurry viscosity and sheet strength. And a plasticizer (DOP) were added and mixed for 3 hours to obtain a slurry.

Using this slurry, a second green sheet 73 (see FIG. 6A) having a thickness of 0.30 mm was produced by a doctor blade method.
Next, a via hole 75 was formed in the first green sheet 71 (see FIG. 6B).

  Next, the via hole 75 was filled with, for example, an Ag-based paste (see FIG. 6C). In addition, a conductive pattern 77 (to be the internal conductor layer 53) was formed by printing using Ag-based paste at a required position on the surface of the first green sheet 71 (see FIG. 6D).

  Next, the first green sheets 71 are sequentially laminated to form a green sheet laminate 79, and further, second ceramic sheets 73 (constraint layers) are laminated on both sides of the green sheet laminate 79. Thus, a composite green sheet laminate 80 is formed (see FIG. 6E).

  Next, the sintered body 81 is formed by firing (degreasing firing) at 850 ° C. for 30 minutes while applying a pressing force of 0.2 MPa from both sides in the stacking direction of the composite green sheet laminate 80 with a press machine. (See FIG. 6 (f)).

Next, the second green sheet 73 remaining on both main surfaces of the sintered body 81 (unsintered) was removed with an ultrasonic cleaner using water as a medium (see FIG. 6G).
Next, both outer surfaces of the sintered body 81 were polished by lapping using alumina abrasive grains (see FIG. 6 (h)). After that, polishing may be performed.

  Next, in the same manner as in the past, sputtering, resist, and plating are performed at predetermined positions on the substrate surface after polishing, that is, at positions where electrodes 49 and 51 are formed so as to cover the surface of via 55 and surface metal layer 57 is formed. Thus, electrodes 49 and 51 and a surface metal layer 57 made of a thin film conductor were formed (see FIG. 6I).

Thereafter, the Au / Sn brazing material is used in the center of the surface metal layer 57, and the Ni / Au plated stud 23 made of Kovar is heated at 320 ° C. for 5 minutes in an N ₂ / H ₂ atmosphere. Then, the semiconductor device inspection substrate 1 which is a multilayer ceramic substrate to which the studs 23 of this embodiment are brazed is completed.

  d) In the semiconductor element testing substrate 1 of this example manufactured in this way, (A) the distance between the circumscribed circle of the brazing material layer 59 and the center of the area of the via 55 around the surface metal layer 57 Z is 2.5 mm or more, and (B) the length ML in the radial direction of the surface metal layer 57 around the center of the area of the bottom surface of the stud 23 and the same radial direction of the bottom surface of the brazing material layer 59 The difference (ML−RL) from the length RL is 0.65 mm or more over the entire circumference of the outer periphery of the stud 23, and (C) the length VL in the radial direction to the center of the area of the via 55 closest to the stud 23. And the length SL of the bottom surface of the stud 23 in the same radial direction (VL / SL) are in the range of 1.6 to 2.0.

Therefore, in the semiconductor element detection substrate 1 in which the difference in linear expansion coefficient between the low-temperature fired ceramic and the low-resistance conductor is as large as 12 ppm / ° C. or more and the stud 23 having a large diameter is brazed, a large external force is applied to the stud 23. However, there is a remarkable effect that cracks are hardly generated at the interface between the low-temperature fired ceramic and the via 55, and therefore, the substrate is hardly broken (that is, the bonding strength of the stud 23 is high).
<Experimental example>
Next, experimental examples conducted for confirming the effects of the present invention will be described.

  Here, as shown below, <1> measurement of thermal expansion coefficient, <2> measurement of bending strength, and <3> measurement of Young's modulus were performed. In addition, samples with different dimensions of various members such as studs were prepared by the manufacturing method of the above-described embodiment, and using the samples, <4> the outermost peripheral portion of the brazing material layer on the outer periphery of the stud (the circumscribed circle) ) And the nearest via disposed around it, <5> measurement of fracture strength when external force was applied to the stud, and observation of the fractured part.

The results are shown in Tables 1 to 4 below. In addition, Examples 1-7 of each table are examples of the present invention, and Comparative Examples 8-15 are comparative examples outside the scope of the present invention.
<1> Measurement of thermal expansion coefficient Each member shown in Tables 1 and 2 (a member made of a low-temperature fired ceramic and a member made of a low-resistance conductor constituting a via) is fired at a predetermined temperature, and then 20 mm long. A sample having a width of 3 mm and a thickness of 4 mm was produced. And the dimensional fluctuation rate to 30-600 degreeC is measured with the thermomechanical analyzer (TMA) with respect to the sample, and elongation ((DELTA) L: elongation from 30 degreeC length L0) and measurement temperature are measured. Sampling. The linear thermal expansion coefficient was obtained by dividing the dimensional change rate (ΔL / L0) between 30 ° C. and 350 ° C. by the temperature difference (ΔT). The results are shown in Tables 1 and 2.

<2> Measurement of Folding Strength From a multilayer ceramic substrate manufactured by the same manufacturing method as in the above embodiment (however, it does not include internal conductor layers and vias, and studs and probes are not joined), 50 mm long × 4 mm wide × A specimen having a thickness of 3 mm was prepared, and the bending strength was measured based on JIS R1610 by using the specimen with a three-point bending strength. The results are shown in Table 1.

<3> Measurement of Young's modulus 50 mm long x 4 mm wide x thickness from a multilayer ceramic substrate manufactured by the same manufacturing method as in the above example (however, it does not include internal conductor layers and vias, and studs and probes are not joined). A 3 mm sample was prepared, and the Young's modulus was measured by a known ultrasonic method using the sample. The results are shown in Table 1.

<4> Measurement of the distance Z between the outermost peripheral part (the circumscribed circle) of the brazing material layer on the outer periphery of the stud and the nearest via disposed around the brazing material layer Using a machine, the distance Z between the outermost peripheral part (the circumscribed circle) of the brazing material layer on the outer periphery of the stud and the center of the nearest via disposed therearound was measured. The results are shown in Table 4.

<5> Measurement of fracture strength when external force of the stud is applied and observation of the fractured part The multilayer ceramic substrate is fixed to the multilayer ceramic substrate with the stud brazed, the stud is pulled vertically, and the load cell (force detection) The breaking strength at that time was measured by a container. The results are shown in Table 4. In addition, as for destruction mode, although the stud was destroyed in the comparative example 8, the ceramic was destroyed in Examples 1-7 and Comparative Examples 9-15.

As apparent from Tables 1 to 4, those having the configuration of the present invention (Examples 1 to 7) have a remarkable effect that the bonding strength is higher (230 kgf or more) than the comparative example.
Further, the comparative example is as follows. In Comparative Example 8, since VL / SL is 5 or more (8.410), the bonding strength is low. In Comparative Examples 9 to 11, since the distance Z is 2.3 mm or less, the bonding strength is low. In Comparative Example 12, since the distance Z is 2.3 mm or less and the (ML-RL) is 0 mm, the bonding strength is low. In Comparative Examples 13 and 14, since (ML-RL) is 0 mm, the bonding strength is low. In Comparative Example 15, although the bonding strength is high, since the ceramic material is not a low-temperature fired ceramic, simultaneous firing at a low temperature is not possible.

  Needless to say, the present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Substrate for semiconductor device inspection 23 ... Stud 45 ... Multilayer ceramic substrate 47 ... Glass ceramic layer 49, 51 ... Surface conductor layer (electrode)
53 ... Inner conductor layer 55 ... Interlayer connection conductor (via)
57 ... Surface metal layer 59 ... Brazing material layer

Claims (4)

It has a plurality of low-temperature fired ceramic layers made of low-temperature fired ceramics, an internal conductor layer made of a low-resistance conductor and an interlayer connection conductor part inside, and at least one surface metal layer on the surface in the thickness direction. Furthermore, a multilayer ceramic substrate in which a protruding member protruding from the substrate surface via a brazing material layer is bonded to the surface metal layer,
When the multilayer ceramic substrate is viewed in the thickness direction,
(A) Between the circumscribed circle of the brazing material layer on the outer periphery of the bottom surface of the projecting member and the center of the area of the interlayer connection conductor portion arranged around the surface metal layer in the low-temperature fired ceramic layer on the outermost surface The distance Z is 2.5 mm or more,
(B) A difference (ML−RL) between a length ML in the radial direction of the surface metal layer and a length RL in the same radial direction of the bottom surface of the brazing material layer around the center of the area of the bottom surface of the protruding member. ) Is 0.65 mm or more over the entire circumference of the outer periphery of the bottom surface of the protruding member,
(C) The length VL in the radial direction from the center of the area of the bottom surface of the protruding member to the area center of the interlayer connection conductor portion closest to the protruding member and the length in the same radial direction of the bottom surface of the protruding member A multilayer ceramic substrate having a ratio (VL / SL) to the thickness SL of 1.6 to 2.0.   2. The multilayer ceramic substrate according to claim 1, wherein a difference in linear thermal expansion coefficient between the low-temperature fired ceramic and the low-resistance conductor in the range of room temperature to 350 ° C. is 12 ppm / ° C. or more.   The low-resistance conductor is one of Ag, Au, and Cu, or a combination or alloy of at least two of Ag, Au, Cu, Pt, Pd, and W. The multilayer ceramic substrate according to claim 1 or 2. In the manufacturing method of the multilayer ceramic substrate according to any one of claims 1 to 3,
Producing a first green sheet made of the low-temperature fired ceramic material;
Forming a through hole in order to form the interlayer connection conductor portion at a predetermined location of the first green sheet;
The through-hole is filled with a conductive paste containing the low-resistance conductor, and a conductive paste containing a low-resistance conductor is applied to form the internal conductor layer at a predetermined location on the surface of the first green sheet. And a process of
A step of laminating a plurality of first green sheets filled and coated with the conductive paste to form a green sheet laminate;
A step of laminating a second green sheet made of a material that does not sinter at a temperature at which the first green sheet sinters on both sides in the thickness direction of the green sheet laminate to form a composite green sheet laminate;
Baking the composite green sheet laminate while degreasing and pressing; and
Removing the unsintered layer made of the second green sheet after the firing;
Polishing the surface of the sintered body after removing the unsintered layer;
Forming the surface metal layer on the surface of the sintered body after polishing;
Brazing the projecting member on the surface metal layer;
A method for producing a multilayer ceramic substrate, comprising: