JP5725886B2 - Device storage package and mounting structure - Google Patents

Description

  The present invention relates to an element storage package and a mounting structure using the element storage package.

  Conventionally, an element storage package having a substrate and an input / output terminal in which a signal line is formed on one main surface of a dielectric layer and a ground layer is formed on the other main surface of the dielectric layer is known ( See Patent Document 1 below). In input / output terminals used at high frequencies such as microwaves and millimeter waves, it is necessary to use a dielectric layer having a low relative dielectric constant and a low dielectric loss in order to efficiently transmit high frequency signals.

JP-A-8-227949

  By the way, by lowering the dielectric constant of the dielectric layer, the difference between the thermal expansion coefficient of the input / output terminals and the thermal expansion coefficient of the substrate may be increased. Then, peeling occurs at the joint portion between the substrate and the input / output terminal, which may impair the airtightness of the package.

  The present invention has been made in view of the above, and an object of the present invention is to provide an element housing package excellent in airtightness and a mounting structure using the element housing package.

An element storage package according to an embodiment of the present invention includes a substrate having an element mounting region on an upper surface thereof, a frame body provided on the substrate so as to surround the mounting region, and having a through hole in part. An input / output terminal provided on the substrate through the through-hole and inside and outside of the frame body, and the outer peripheral edge of the upper surface of the substrate has a curvature of the outer peripheral edge of the upper surface of the substrate. A curved portion that is smaller than the curvature of the outer peripheral edge of the lower surface is provided, and an end face of the input / output terminal located in a region not surrounded by the frame body is located immediately above the curved portion. Features.

  In addition, a mounting structure according to an embodiment of the present invention includes the element storage package and an element mounted in the mounting region of the element storage package.

  ADVANTAGE OF THE INVENTION According to this invention, the mounting structure which uses the element storage package excellent in airtightness and the element storage package can be provided.

It is a perspective view showing the appearance of the mounting structure concerning this embodiment. It is a perspective view which shows the external appearance of the input / output terminal of the mounting structure which concerns on this embodiment. It is sectional drawing of the mounting structure along X-X 'shown in FIG.

  Exemplary embodiments of an element storage package and a mounting structure according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited to the following embodiment.

<Schematic configuration of mounting structure>
FIG. 1 is a schematic perspective view showing a mounting structure 1 according to the present embodiment. FIG. 2 is a perspective view showing an overview of input / output terminals used in the mounting structure 1 of FIG. The mounting structure 1 is used for home appliances such as a television, and electronic devices such as a mobile phone or a computer device. In particular, it is used for a high-frequency circuit of an electronic device used at a high frequency such as a microwave and a millimeter wave.

  The mounting structure 1 includes an element storage package 2 and an element 3 mounted on the element storage package 2. The element storage package 2 includes, for example, an active element such as a semiconductor element, an optical semiconductor element, a transistor, a diode, or a thyristor, or a passive element such as a resistor, a capacitor, a solar cell, a piezoelectric element, a crystal oscillator, or a ceramic oscillator. Used to mount the element 3.

  The element storage package 2 includes a substrate 4 having a mounting region R of the element 3 on the upper surface, a frame 5 provided on the substrate 4 so as to surround the mounting region R, and a part having a through hole H, and a through hole. And an input / output terminal 6 provided through the hole H over the inside and outside of the frame body 5. The element storage package 2 can be used as the mounting structure 1 by mounting the element 3 in the mounting region R of the substrate 4 and electrically connecting the element 3 and the input / output terminal 6.

  The substrate 4 is a member formed in a square shape when viewed in plan. The substrate 4 is made of, for example, a metal material such as copper, iron, tungsten, molybdenum, nickel, or cobalt, or an alloy containing these metal materials. The substrate 4 has a function of improving heat conductivity and dissipating heat generated from the element 3 mounted in the mounting region R to the outside efficiently through the substrate 4. The thermal conductivity of the substrate 4 is set to, for example, 15 W / (m · K) or more and 450 W / (m · K) or less. Moreover, the thermal expansion coefficient of the board | substrate 4 is set to 4-18, for example.

  Further, the substrate 4 is manufactured in a predetermined shape by using a conventionally known metal processing method such as rolling or stamping for an ingot obtained by casting a molten metal material into a mold and solidifying it. The The length of one side of the substrate 4 is set to, for example, 3 mm or more and 50 mm or less. Moreover, the thickness of the board | substrate 4 is set to 0.3 mm or more and 5 mm or less, for example.

  Further, a plating layer such as nickel or gold is formed on the surface of the substrate 4 by using an electroplating method or an electroless plating method in order to prevent oxidative corrosion or to easily braze the element 3 to the mounting region R. Has been. The mounting region R of the substrate 4 is a region that is not connected to the frame body 5 when the frame body 5 is connected to the upper surface of the substrate 4. In the present embodiment, the shape of the substrate 4 is a quadrangle when viewed in plan, but is not limited to a quadrangle when viewed in plan, as long as the element 3 can be mounted. An elliptical shape or the like may be used.

At the outer peripheral edge of the upper surface of the substrate 4, the curvature of the outer peripheral edge of the upper surface of the substrate 4 (the curvature from the upper surface to the side surface) when viewed in cross section in the thickness direction of the substrate 4 is 4 A of curved parts smaller than a curvature (curvature from a lower surface to a side surface) are formed. The curved portion 4A can provide a gap along the outer peripheral edge of the upper surface of the substrate 4 between the outer peripheral edge of the upper surface of the substrate 4 and the lower surface of the input / output terminal 6 provided immediately above the curved portion 4A. The substrate 4 is formed such that the outer peripheral edge of the upper surface of the substrate 4 is smoothly formed, so that the contact area with the input / output terminals 6 provided on a part of the outer periphery on the substrate 4 can be reduced. When heat is applied to the substrate 4 and the temperature rises, the substrate 4 may be warped. However, when the substrate 4 is thermally deformed, the outer peripheral edge of the upper surface of the substrate 4 applies stress to the input / output terminals 6. . Therefore, the curved portion 4A is formed on the outer peripheral edge of the upper surface of the substrate 4 where the warpage is the largest, so that the outer peripheral edge of the upper surface of the substrate 4 that has caused thermal expansion comes into contact with the input / output terminal 6 and then the input / output terminal 6 Since the stress is applied to the bending portion 4A,
Compared to the case where the outer peripheral edge of the substrate 4 is in contact with the input / output terminal 6 from the beginning, the stress applied to the input / output terminal 6 can be reduced.

  Further, the curved portion 4 </ b> A is preferably provided continuously over the entire outer periphery of the upper surface of the substrate 4. By providing the curved portion 4A continuously over the entire outer periphery of the upper surface of the substrate 4, due to the difference in thermal expansion coefficient between the substrate 4 or the frame 5 and the input / output terminal 6 in the manufacturing process of the element storage package. The generated stress can be made difficult to concentrate locally at the outer peripheral edge of the upper surface of the substrate 4. Further, in the manufacturing process of the element housing package 2, the mounting structure 1 is mounted on the external electric circuit board due to warpage of the board 4 caused by the difference in thermal expansion coefficient between the board 4 or the frame 5 and the input / output terminal 6. It is possible to make it difficult for the stress generated by the correction at the time to be locally concentrated on the outer peripheral edge of the substrate 4. If a portion where the curved portion 4A is formed and a portion where the curved portion 4A is not formed are provided on the outer peripheral edge of the substrate 4, the stress on the outer peripheral edge of the substrate 4 causes the curved portion 4A to be formed. It will concentrate in the boundary part of a site | part and the site | part in which the curved part 4A is not formed. Similarly, the stress caused by the difference in thermal expansion coefficient between the substrate 4 or the frame 5 and the input / output terminal 6 due to the heat generated from the element 3 when the mounting structure 1 is operated is applied to the outside of the upper surface of the substrate 4. It is possible to make it difficult to concentrate locally at the periphery.

  The curvature of the curved portion 4A on the outer peripheral edge of the upper surface of the substrate 4 is set to 1 or more and 10 or less, for example. Further, the curvature of the outer peripheral edge of the lower surface of the substrate 4 is set to, for example, 5 or more and 20 or less. The curvature of the outer peripheral edge of the upper surface of the substrate 4 is formed to be smaller than the curvature of the outer peripheral edge of the lower surface of the substrate 4. The curvature is a numerical value represented by 1 / r when the radius of the circumference of the curved portion at the outer peripheral edge of the substrate 4 is r (mm).

  Further, the flat area of the lower surface of the substrate 4 is made larger than the flat area of the upper surface of the substrate 4 by making the curvature of the outer peripheral edge of the lower surface of the substrate 4 larger than the curvature of the outer peripheral edge of the upper surface of the substrate 4. Can do. And the contact area with the external board | substrate which mounts the board | substrate 4 can be enlarged, and the adhesive force of the board | substrate 4 and an external board | substrate can be improved.

  The frame 5 is a member that is provided so as to surround the mounting region R of the substrate 4 and protects the element 3 from the outside. Further, the frame body 5 is formed with a through hole H provided with the input / output terminal 6 in a part of the side surface. The frame 5 is brazed to the substrate 4 via a brazing material. The brazing material is made of, for example, silver, copper, gold, aluminum, or magnesium, and may contain additives such as nickel, cadmium, or phosphorus.

  The frame 5 is made of, for example, a metal material such as copper, iron, tungsten, molybdenum, nickel, or cobalt, or an alloy containing these metal materials. The frame 5 has a function of efficiently dissipating heat generated from the element 3 to the outside of the frame 5 in a state where the element 3 is mounted in the mounting region R. The thermal conductivity of the frame 5 is set to, for example, 15 W / (m · K) or more and 450 W / (m · K) or less. Moreover, the thermal expansion coefficient of the frame 5 is set to, for example, 4 ppm / ° C. or more and 18 ppm / ° C. or less.

  The input / output terminal 6 is provided in the through hole H of the frame body 5. The input / output terminal 6 is for transmitting high-frequency signals such as microwaves and millimeter waves. The input / output terminal 6 includes a first dielectric layer 6a and a second dielectric layer 6b provided on a part of the first dielectric layer 6a. Furthermore, the input / output terminal 6 is formed between the first dielectric layer 6a and the second dielectric layer 6b, and electrically connects the signal line 7 between the inside and outside of the frame 5 and the first dielectric layer 6a. The first ground conductor 8 formed on the lower surface and the second ground conductor 9 provided continuously on the side surface of the first dielectric 6a, the side surface of the second dielectric layer 6b, and the upper surface of the second dielectric layer 6b are provided. doing.

The signal line 7 has a function of transmitting a predetermined electrical signal. The signal line 7 is, for example,
Used as a microstrip line or coplanar line. The signal line 7 is formed by forming a nickel plating layer or a gold plating layer on a metallized metal layer formed of tungsten, molybdenum, manganese, or the like. Further, the line width of the signal line 7 is not more than one-fourth of the wavelength of the signal transmitted to the signal line 7, and is set to, for example, 0.05 mm or more and 0.5 mm or less.

  A lead terminal 10 is formed on the signal line 7. The lead terminal 10 is a member for electrically connecting an external electronic device or the like to the element 3. The lead terminal 10 is connected to the signal line 7 through a brazing material. The signal line 7 and the lead terminal 10 are electrically connected.

  The first ground conductor 8 and the second ground conductor 9 have a function of setting a common potential, for example, a ground potential. The first ground conductor 8 and the second ground conductor 9 are formed by forming a nickel plating layer on a metallized metal layer made of tungsten, molybdenum, manganese, or the like, for example. The first ground conductor 8 is formed in a region overlapping the signal line 7 in plan view. The frame 5 is made of a metal material, and the first ground conductor 8, the second ground conductor 9, and the frame 5 are electrically connected.

  The input / output terminal 6 has a second ground conductor 9 that surrounds the first dielectric layer 6a and the second dielectric layer 6b, and is connected to the signal line 7 in a region where the signal line 7 and the frame 5 overlap. It is possible to suppress reflection of the transmitted signal.

  The first dielectric layer 6a and the second dielectric layer 6b are insulating substrates, for example, inorganic materials such as aluminum oxide, aluminum nitride, or silicon nitride, or organic materials such as epoxy resin, polyimide resin, or ethylene resin. It is made of a material, a ceramic material such as alumina or mullite, or a glass ceramic material. Or it consists of a composite material which mixed several materials among these materials. The thicknesses of the first dielectric layer 6a and the second dielectric layer 6b are not more than one half of the wavelength of the signal transmitted to the signal line 7, and are set to, for example, not less than 0.1 mm and not more than 1 mm.

  The first dielectric layer 6a or the second dielectric layer 6b may contain a large number of fillers. When the first dielectric layer 6a or the second dielectric layer 6b is made of an organic material, a filler is contained in the first dielectric layer 6a or the second dielectric layer 6b, whereby the first dielectric layer 6a. Or the viscosity before hardening of the 2nd dielectric material layer 6b can be adjusted, and the thickness dimension of the 1st dielectric material layer 6a or the 2nd dielectric material layer 6b can be brought close to a desired value. The filler is, for example, spherical, the filler diameter is set to, for example, 0.05 μm to 6 μm, and the coefficient of thermal expansion is, for example, −5 ppm / ° C. to 5 ppm / ° C. The filler is made of, for example, silicon oxide, silicon carbide, aluminum oxide, aluminum nitride, or aluminum hydroxide.

  The relative dielectric constant of the filler contained in the first dielectric layer 6a or the second dielectric layer 6b is smaller than the relative dielectric constant of the material constituting the first dielectric layer 6a or the second dielectric layer 6b. Can be set. Thus, by using a filler having a low dielectric constant smaller than the relative dielectric constant of the first dielectric layer 6a or the second dielectric layer 6b, the input / output terminal 6 can be further reduced in dielectric constant, The transmission efficiency of the signal transmitted to the line 7 can be improved.

  The filler can be an insulating filler. By making the filler insulative, the influence on the characteristic impedance of the signal transmitted to the signal line 7 can be reduced.

The signal transmitted to the signal line 7 changes in transmission characteristics due to the material located directly above or below the signal line 7, but when the change in transmission characteristics is large, the reflection of the signal transmitted to the signal line 7 The amount increases. The signal line 7 is formed to extend in and out of the frame 5 in order to electrically connect the inside and outside of the frame 5. Therefore, in the area where the signal line 7 and the frame 5 overlap in plan view, the change in transmission characteristics of the signal transmitted to the signal line 7 is large. In the present embodiment, in the region where the signal line 7 and the frame 5 overlap, a part of the dielectric layer is bonded directly above and directly below the signal line 7 to reduce the region where the signal line 7 is in contact with the atmosphere. As a result, it is possible to suppress a change in transmission characteristics of the signal transmitted to the signal line 7 and reduce high-frequency reflection transmitted to the signal line 7.

  The outer peripheral edge of the lower surface of the input / output terminal 6 is formed flat. The curved portion 4 </ b> A is curved from the outer peripheral edge of the lower surface of the input / output terminal 6. By forming the lower surface of the input / output terminal 6 flat, the change in the reflection of electromagnetic waves between the signal line 7 and the first ground conductor 8 can be reduced, and the transmission characteristics of the input / output terminal 6 can be maintained well. it can.

  An end face located in a region not surrounded by the frame 5 of the input / output terminal 6 is set so as to overlap the curved portion 4A of the substrate 4 in plan view. By matching the end face of the input / output terminal 6 and the end face of the substrate 4, it is possible to suppress the deterioration of the transmission characteristics of the input / output terminal 6 and the occurrence of damage such as cracking or chipping of the input / output terminal 6. If the end face of the input / output terminal 6 is provided on the inner side of the outer periphery of the substrate 4 in plan view, a capacitance component is generated between the lead terminal 10 and the outer peripheral edge of the substrate 4. The characteristic impedance varies. As a result, the reflection loss at the input / output terminal 6 increases, and the transmission characteristics of the signal line 7 deteriorate. If the end face of the input / output terminal 6 protrudes outside the outer periphery of the substrate 4, the input / output terminal 6 is positioned outside the substrate 4 in a plan view. When the assembly 2 and the mounting structure 1 are mounted on the external electric circuit board, there is a possibility that the input / output terminal 6 directly contacts a tool such as tweezers or a conveying jig. As a result, damage such as cracking or chipping occurs in the input / output terminal 6, and the yield tends to decrease with the reliability of the element housing package 2 and the mounting structure 1.

  The mounting structure 1 can be configured by mounting the element 3 in the mounting region R of the base body 4 via solder or the like in the element storage package 2. When a semiconductor element such as an IC or LSI is mounted, for example, silicon, germanium, gallium arsenide, gallium arsenide phosphorus, gallium nitride, or silicon carbide can be used as the semiconductor element. Further, the upper surface of the element 3 and the signal line 7 of the input / output terminal 6 located in the frame 5 are electrically connected via a bonding wire.

  A lid 11 is provided on the frame 5. The lid 11 has a function for maintaining the airtightness in the frame 5. The lid 11 is made of, for example, a metal such as copper, tungsten, iron, nickel, or cobalt, or an alloy containing a plurality of these metals, an aluminum oxide sintered body, a mullite sintered body, or a silicon carbide sintered body. And made of ceramics such as an aluminum nitride sintered body, a silicon nitride sintered body, or a glass ceramic. The lid 11 is joined to the upper surface of the frame 6 via a joining member such as solder or brazing material.

  According to the present embodiment, due to the difference between the thermal expansion coefficient of the substrate 4 and the thermal expansion coefficient of the input / output terminal 6, even when both are thermally expanded, the curved portion 4A is provided on the outer peripheral edge of the substrate 4. Further, it is possible to make it difficult for thermal stress to be applied from the substrate 4 to the input / output terminals 6, to prevent the input / output terminals 6 from being broken, and to maintain good airtightness of the package. Further, by making the input / output terminal 6 difficult to be deformed, it is possible to prevent the transmission characteristics of the signal line 7 from being deteriorated, and to provide the element housing package 2 and the mounting structure 1 having excellent electrical characteristics. Can be provided.

In addition, this invention is not limited to the above-mentioned form, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention. For example, a structure in which a wiring board is interposed between the base 4 and the element 3 may be used.

<Method for manufacturing mounting structure>
Here, a manufacturing method of the mounting structure 1 shown in FIG. 1 will be described. First, each of the substrate 4 and the frame 5 is prepared. Each of the substrate 4 and the frame 5 is manufactured in a predetermined shape by using a metal processing method such as metal polishing on a solidified ingot obtained by casting a molten metal material into a mold. In addition, the board | substrate 4 can grind | polish the location corresponding to the outer periphery of the upper surface of the board | substrate 4 with respect to the ingot taken out from the formwork, and can form the curved part 4A. Further, the frame body 5 can polish a portion corresponding to the through hole H to form a through hole H having a size capable of connecting the input / output terminal 6.

  Next, the input / output terminal 6 is prepared. Here, the material of the dielectric layer 6 can be an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, or the like.

  When the material of the dielectric layer 6 is made of an aluminum oxide sintered body, first, an organic binder, a plasticizer, a solvent, or the like is added to and mixed with raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, or calcium oxide to form a slurry. And

  Then, molds of the first dielectric layer 6a and the second dielectric layer 6b are prepared, and the frame body is filled with a slurry-like aluminum oxide material, and the first dielectric layer 6a before sintering is filled. Then, the second dielectric layer 6b is taken out.

  Moreover, a high melting point metal powder such as tungsten or molybdenum is prepared, and an organic binder, a plasticizer, a solvent, or the like is added to and mixed with the powder to obtain a metal paste.

  Then, the signal line 7 is formed by applying a metal paste to the upper surface of the taken out first dielectric layer 6a before sintering using, for example, a screen printing method. The first ground conductor 8 is formed on the lower surface of the first dielectric layer 6a by applying a metal paste, for example, using a screen printing method. Further, when the first dielectric layer 6a and the second dielectric layer 6b are combined, the second ground conductor 9 is formed at a location surrounding both by using, for example, a screen printing method.

  Next, the second dielectric layer 6b before sintering is placed on the first dielectric layer 6a before sintering and pressed, thereby bringing them into close contact with each other. Then, the laminated body on which the metal paste is printed is fired at a temperature of about 1600 ° C., thereby producing the input / output terminal 6 made of ceramics on which the signal line 7, the first ground conductor 8 and the second ground conductor 9 are formed. can do.

  Then, the input / output terminal 6 is fitted and connected to the through hole H of the prepared frame 5 through a brazing material. In this way, the element storage package 2 can be manufactured.

  Next, the element 3 is mounted on the mounting region R of the element storage package 2 via solder, and the electrode of the element 3 is electrically connected to the signal line 7 of the input / output terminal 6 via a bonding wire. Furthermore, the mounting structure 1 can be produced by joining the lid 11 on the frame 5 via a joining member such as solder or brazing material.

DESCRIPTION OF SYMBOLS 1 Mounting structure 2 Element accommodation package 3 Element 4 Board | substrate 4A Bending part 5 Frame 6 Input / output terminal 6a First dielectric layer 6b Second dielectric layer 7 Signal line 8 First ground conductor 9 Second ground conductor 10 Lead Terminal 11 Lid R Mounting area H Through hole

Claims (4)

A substrate having an element mounting region on the upper surface;
A frame having a part of a through hole provided on the substrate so as to surround the mounting region, and an input / output terminal provided on the substrate through the through hole and inside and outside the frame. Prepared,
The outer peripheral edge of the upper surface of the substrate is provided with a curved portion in which the curvature of the outer peripheral edge of the upper surface of the substrate is smaller than the curvature of the outer peripheral edge of the lower surface of the substrate,
An element storage package, wherein an end face of the input / output terminal located in a region not surrounded by the frame is located immediately above the bending portion. The device storage package according to claim 1,
The element storage package, wherein the curvature of the outer peripheral edge of the upper surface of the substrate is smaller than the curvature of the outer peripheral edge of the lower surface of the input / output terminal. The element storage package according to claim 1 or 2,
The package for storing elements, wherein the curved portion is continuously provided over the entire outer periphery of the substrate. The element storage package according to any one of claims 1 to 3,
A mounting structure comprising: an element mounted in the mounting region of the element storage package.

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