JP2008244178A - Element packaging substrate and manufacturing method thereof, and infrared detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an element packaging substrate capable of preventing the shape of a recess from changing by suppressing the exudation of the resin of a first insulating layer from the inner wall of a hole section. <P>SOLUTION: In the manufacturing method of the element packaging substrate A, at least one through hole section 2 is provided in the first insulating layer 1 in a B stage state, and a hole 4 is provided on a metal sheet 3. The metal sheet 3 is laminated on one side of the first insulating layer 1 while the hole section 2 coincides with the hole 4 before the first insulation layer 1 is cured by heating, pressurizing, and molding, the metal sheet 3 is bonded to the first insulating layer 1, and the recess 5 for heat insulation is formed at the hole section 2. Before the heating, pressurizing, and molding, a thermoplastic film 6 is laminated to the metal sheet 3 so that the hole section 2 of the first insulating layer 1 is blocked. The hole section 2 is filled with the resin of the thermoplastic film 6 softened by heating and pressurizing. After the heating, pressurizing, and molding, the thermoplastic film 6 is separated to remove the resin from the hole section 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an element mounting board formed by providing a recess for thermal insulation on the surface, a manufacturing method thereof, and an infrared detector formed using the element mounting board.

  The element mounting board A formed by providing the heat insulating recess 5 on the surface is used for manufacturing the infrared detector B (see, for example, Patent Document 1). Conventionally, such an element mounting board A is basically manufactured through a process as shown in FIG. That is, first, as shown in FIG. 7A, the metal sheet 3, the first insulating layer 1 in the B stage state, the first circuit board 7 provided with the circuit 13 on the surface, the second insulating layer 8 in the B stage state, The second circuit board 10 on which the circuit 13 is provided on the surface and on which the element 9 is mounted is laminated in this order, and a mold 27 provided with a convex portion 26 on the metal sheet 3 side is disposed. Then, as shown in FIG. 7 (b), the mold 27 is pressed against the above laminate using a press device (not shown), and after heat and pressure molding, the mold is removed as shown in FIG. 7 (c). The element mounting board | substrate A with 5 provided in the surface can be obtained.

  However, in the manufacturing method as described above, since the mold 27 is pressed against the first insulating layer 1 through the metal sheet 3, the first along the shape of the convex portion 26 of the mold 27. It is difficult to deform the insulating layer 1 by following it, and there is a problem that the opening edge of the concave portion 5 is actually bent as shown in FIG. And since the pyroelectric element 12 is mounted across the recessed part 5 in manufacturing the infrared detector B, if the opening edge of the recessed part 5 is slanted as described above, a mounting defect as shown in FIG. Or the sensitivity of the pyroelectric element 12 is reduced.

  Such a problem can be solved for example through a process as shown in FIG. That is, as shown in FIGS. 9A and 9B, the metal sheet 3, the first insulating layer 1, the first circuit board 7, the second insulating layer 8, and the second circuit board 10 are stacked in this order by heating and pressing. After molding, the recess 5 is provided by spot facing as shown in FIG. However, in general, counterbore processing takes time, and a high degree of processing accuracy is required to flatly expose the bottom surface of the recess 5, so that it is not practical.

Therefore, at present, the element mounting board A is manufactured by the method shown in FIG. That is, as shown in FIG. 10A, the metal sheet 3 provided with the through holes 4 in advance, the first insulating layer 1, the first circuit board 7, and the second insulating layer 8 provided with the through holes 2 in advance. The second circuit board 10 is stacked in this order and heated and pressed to form a laminate. With such a method, the recess 5 can be provided in a short time, and the opening edge of the recess 5 can be prevented from sagging.
JP-A-5-332829

  However, in the method as shown in FIG. 10, the resin of the first insulating layer 1 oozes out from the inner wall of the concave portion 5 as shown in FIG. There is a problem of changing. When the infrared detector B is manufactured, the pyroelectric element 12 is mounted across the recess 5 as shown in FIG. 11B, but the distance between the pyroelectric element 12 and the bottom surface of the recess 5 becomes uneven. If the shape of the concave portion 5, particularly the cross-sectional area of the concave portion 5 is changed, the sensitivity of the pyroelectric element 12 is adversely affected. In this case, it is conceivable to adjust the shape of the recess 5 by performing a desmear process such as a plasma method before mounting the pyroelectric element 12, but it is difficult to remove only unnecessary resin by such a process.

  It is also conceivable to use ceramic for the first insulating layer 1. That is, a plurality of green sheets provided with holes 2 penetrating in advance are stacked and sintered. In this case, the resin does not ooze out from the inner wall of the recess 5, but the ceramic substrate has a problem that the dimensional stability is poor in the first place.

  The present invention has been made in view of the above points, and an element mounting substrate that can prevent the resin of the first insulating layer from seeping out from the inner wall of the hole and prevent the shape of the recess from changing. It is an object of the present invention to provide an infrared detector.

  In the method for manufacturing an element mounting board according to claim 1 of the present invention, at least one or more through holes 2 are provided in the first insulating layer 1 in the B stage state, and the holes 4 are provided in the metal sheet 3. After the metal sheet 3 is laminated on one side of the first insulating layer 1 while the portion 2 and the hole 4 are aligned, the first insulating layer 1 is cured by heating and pressing, and the first insulating layer 1 is coated with the metal. A manufacturing method of an element mounting board A in which a sheet 3 is bonded and a recess 5 for thermal insulation is formed in the hole 2, and the hole of the first insulating layer 1 is formed before heat and pressure molding. The thermoplastic film 6 is laminated on the metal sheet 3 so as to block 2, the hole 2 is filled with the resin of the thermoplastic film 6 softened by heating and pressing, and the thermoplastic film 6 is peeled after the heating and pressing. And removing the resin from the hole 2 A.

  The invention according to claim 2 is the first circuit board 7 on the side opposite to the side on which the metal sheet 3 of the first insulating layer 1 is laminated before the heat and pressure forming, and the second in the B stage state. The second circuit board 10 on which the insulating layer 8 and the element 9 are mounted is laminated in this order, and the first insulating layer 1 and the second insulating layer 8 are cured by heating and pressing, so that the first insulating layer 1 The first circuit board 7 is bonded, and the first circuit board 7 and the second circuit board 10 are bonded while the element 9 is embedded in the second insulating layer 8.

  The invention according to claim 3 is characterized in that, in claim 1 or 2, there is at least a state in which the fluidity of the thermoplastic film 6 is higher than the fluidity of the first insulating layer 1 during the heat and pressure molding. It is what.

  The invention according to claim 4 is characterized in that, in any one of claims 1 to 3, a thermoplastic film 6 having a release layer 11 on at least a surface facing the hole 2 is used. To do.

  An element mounting board according to a fifth aspect of the present invention is manufactured using the method according to any one of the first to fourth aspects.

  The infrared detector according to claim 6 of the present invention is formed using the element mounting board A while mounting the pyroelectric element 12 across the recess 5 of the element mounting board A according to claim 5. It is characterized by.

  According to the method for manufacturing an element mounting board of claim 1 of the present invention, the resin of the thermoplastic film softened during the heat and pressure molding is filled in the hole portion, so that the resin of the first insulating layer is the hole. Bleeding from the inner wall of the part can be suppressed and the shape of the recess can be prevented from changing.

  According to the invention which concerns on Claim 2, multilayering and high-density mounting can be achieved easily.

  According to the invention of claim 3, the resin of the thermoplastic film can be filled into the hole before the resin of the first insulating layer oozes from the inner wall of the hole, and the resin of the first insulating layer oozes out. Can be more reliably prevented.

  According to the invention which concerns on Claim 4, peeling of a thermoplastic film can be performed easily by a mold release layer.

  According to the element mounting substrate of claim 5 of the present invention, the resin of the first insulating layer does not ooze out to the inner surface of the recess.

  According to the infrared detector of claim 6 of the present invention, the detection sensitivity can be increased.

  Embodiments of the present invention will be described below.

  FIG. 1 shows an example of an embodiment of the present invention. In this example, first, first and second insulating layers 1 and 8 in a B-stage state, a metal sheet 3, a first circuit board 7, and a second circuit are shown. A substrate 10 and a thermoplastic film 6 are prepared.

  As the first insulating layer 1 and the second insulating layer 8 in the B stage state, for example, a resin composition or a thermoplastic resin prepared by blending 50 to 95% by mass of an inorganic filler with a thermosetting resin or a thermoplastic resin. A single body formed into a sheet having a thickness of 10 to 1000 μm (organic green sheet), or a prepreg obtained by impregnating a base material such as glass cloth with the resin composition and drying can be used. Here, examples of the thermosetting resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, aralkyl epoxy resin, phenol novolac type epoxy resin, alkylphenol novolac type epoxy resin, and biphenol type epoxy resin. Naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, epoxidized product of condensate of phenol and aromatic aldehyde having phenolic hydroxyl group, triglycidyl isocyanurate, alicyclic epoxy resin and the like can be used. As the thermoplastic resin, polyimide resin, liquid crystal polymer resin, polyether ether ketone resin, polyphenylene sulfide resin, polyamide resin, or the like can be used. Examples of the inorganic filler include aluminum oxide, magnesium oxide, boron nitride, aluminum nitride, silica, barium titanate, titanium oxide, magnesium hydroxide, aluminum hydroxide, antimony trioxide, antimony pentoxide, guanidine salt, and boron. Zinc acid, molybdenum compound, zinc stannate, talc, barium sulfate, calcium carbonate, mica powder and the like can be used. The resin composition may contain a curing agent such as dicyandiamide, phenol, or acid anhydride. The first insulating layer 1 in the B stage state is provided with at least one through hole 2. For example, the hole 2 can be formed in a long hole shape in a plan view, but is not limited thereto. On the other hand, the hole 2 is not provided in the second insulating layer 8 in the B stage state.

  Moreover, as the metal sheet 3, metal foils, such as copper foil with a thickness of 1-70 micrometers, can be used, for example. The metal sheet 3 is provided with holes 4 having the same shape and the same number as the holes 2 provided in the first insulating layer 1. In particular, as shown in FIG. 3, the distance w between the inner edge of the hole 4 of the metal sheet 3 and the inner edge of the hole 2 of the first insulating layer 1 is preferably 20 to 150 μm. When the inner diameter of the hole 4 of the metal sheet 3 is equal to or smaller than the inner diameter of the hole 2 of the first insulating layer 1, the inner edge of the hole 4 of the metal sheet 3 is the hole of the first insulating layer 1 during the heat and pressure molding. However, if the inner diameter of the hole 4 of the metal sheet 3 is larger than the inner diameter of the hole 2 of the first insulating layer 1 as described above, It is possible to prevent the inner edge portion of the hole 4 of the metal sheet 3 from being dragged into the hole portion 2 of the first insulating layer 1 during the pressure forming.

  In addition, as the first circuit board 7 and the second circuit board 10, a multilayer circuit board or the like manufactured by using a subtractive method or the like on a metal-clad laminate can be used. Circuits 13 are formed on both surfaces of the first circuit board 7, and the circuits 13 on both surfaces are electrically connected by an interlayer connection 14 such as through-hole plating. A circuit 13 is formed on one side of the second circuit board 10 and an element 9 such as a chip resistor or a chip capacitor is mounted on the other side. The metal sheet 3 is provided on the entire other side, and the circuit 13 and the metal sheet are also provided. 3 is electrically connected by an interlayer connection 14 such as through-hole plating.

  As the thermoplastic film 6, for example, a thermoplastic resin such as a polyolefin resin formed into a sheet having a thickness of 10 to 1000 μm can be used, but the thickness is not limited to this range. In particular, as the thermoplastic film 6, it is preferable to use a film that has at least a state in which the fluidity is higher than the fluidity of the first insulating layer 1 during the heat and pressure molding described later. Specifically, for example, when the organic green sheet described above is used as the first insulating layer 1 in the B-stage state, it is preferable to use a thermoplastic film 6 formed of a polyolefin resin. Furthermore, it is preferable that a release layer 11 having a thickness of 1 to 200 μm is provided on one side or both sides of the thermoplastic film 6 as shown in FIGS. The release layer 11 can be formed of a polyolefin resin having releasability such as a fluororesin, a silicone resin, or polymethylpentene.

Here, the magnitude relationship between the fluidity of the thermoplastic film 6 and the first insulating layer 1 in the B-stage state can be confirmed in advance as follows. For example, as shown in FIG. 6A, a circular thermoplastic film 6 (100 mmφ, thickness 200 μm) is sandwiched between two release films 29, which are further sandwiched between two molding plates 28, and this is pressed. (Not shown) Heat and pressure molding is performed. The molding conditions at this time are set to, for example, a temperature of 70 ° C., a pressure of 5 MPa (51.0 kg / cm ² ), and a time of 10 minutes. The fluidity can be quantified by calculating the area of the thermoplastic film 6 before and after molding and using these areas as in the following equation.

Fluidity (%) = [Area after molding / Area before molding] × 100
In this way, the fluidity of the thermoplastic film 6 can be obtained as a numerical value. On the other hand, the fluidity of the first insulating layer 1 in the B-stage state can be similarly obtained as a numerical value. [Table 1] below shows an example of the fluidity relationship between the thermoplastic film 6 and the first insulating layer 1 in the B stage state at temperatures of 70 ° C., 90 ° C., 110 ° C., and 130 ° C.

  As described above, by changing not only the temperature but also the pressure and time as appropriate, the magnitude relationship between the fluidity of the thermoplastic film 6 and the first insulating layer 1 in the B stage state can be confirmed in advance.

  In manufacturing the element mounting substrate A, first, as shown in FIG. 1A, the metal sheet 3 is laminated on one surface of the first insulating layer 1 in the B stage state while the hole 2 and the hole 4 are matched, A first circuit board 7, a B-stage second insulating layer 8, and a second circuit board 10 on which an element 9 is mounted are laminated in this order on the side of the first insulating layer 1 opposite to the side where the metal sheet 3 is laminated. . At this time, the surface of the second circuit board 10 on which the element 9 is mounted faces the second insulating layer 8 side. Further, a thermoplastic film 6 is laminated on the metal sheet 3 so as to close the hole 2 of the first insulating layer 1 on the side of the metal sheet 3 provided with the holes 4.

  Thereafter, the laminate is sandwiched between two plates (not shown), and if necessary, a release sheet or metal foil is interposed between the laminate and the plate. The first insulating layer 1 and the second insulating layer 8 are cured until they are in the C-stage state, and the metal sheet 3 and the first circuit board 7 are bonded to the first insulating layer 1. Let The first circuit board 7 is bonded to the second insulating layer 8, and the second circuit board 10 is bonded to the second insulating layer 8 while embedding the elements 9. The step of heat and pressure molding can be divided into a primary step (mainly a step of filling the resin of the thermoplastic film 6) and a secondary step (mainly a step of curing the first insulating layer 1). The molding conditions in the primary step can be set to, for example, 70 to 150 ° C., 1 to 10 MPa, and 5 minutes to 1 hour. In addition, you may apply a pressure of about 0.1-1 MPa until it reaches the temperature of a primary process for prevention of the shift | offset | difference of a laminated body. On the other hand, the molding conditions in the secondary process can be set to 150 to 230 ° C., 1 to 10 MPa, and 30 minutes to 5 hours, for example. The thermoplastic film 6 is softened by such heat and pressure, and the resin enters the hole 2 of the first insulating layer 1 and fills the hole 2. As described above, the resin of the thermoplastic film 6 softened during the heat and pressure molding is filled in the hole 2, thereby suppressing the resin of the first insulating layer 1 from seeping out from the inner wall of the hole 2. The shape of the recess 5 can be prevented from changing. In addition, when there is at least a state in which the fluidity of the thermoplastic film 6 is higher than the fluidity of the first insulating layer 1 during the heat and pressure molding, the resin of the first insulating layer 1 is the inner wall of the hole 2. The resin of the thermoplastic film 6 can be filled in the hole 2 before it oozes out from the resin, and the oozing of the resin of the first insulating layer 1 can be prevented more reliably. In addition, it is preferable to perform heat-press molding in a vacuum atmosphere from the point of the filling property of the thermoplastic film 6 and the void reduction of the 1st insulating layer 1 and the 2nd insulating layer 8.

  Then, after confirming that the thermoplastic film 6 has been cured again after the heat and pressure molding, the thermoplastic film 6 is peeled off as shown in FIG. It is possible to obtain the element mounting substrate A in which the hole 2 has the recess 5 for heat insulation. In particular, as the thermoplastic film 6, as shown in FIG. 4 described above, in the case where a release layer 11 is provided at least on the surface facing the hole 2, the release layer 11 allows the thermoplastic film 6 to be formed. It can be easily peeled off.

  In the element mounting board A manufactured in this way, the first circuit board 7 and the second circuit board 10 are used, and the element 9 mounted on the second circuit board 10 has the second insulating layer. 8 can be easily multi-layered and mounted with high density.

  In manufacturing the infrared detector B, first, the circuit 13 is formed on the outermost layer of the element mounting board A as shown in FIG. At this time, the circuit 13 on the upper surface of the opening edge of the recess 5 is formed as a land 15 for mounting the pyroelectric element 12. Thereafter, the electrodes 15 on both sides of the pyroelectric element 12 and the land 15 are bonded using a conductive paste 16 such as silver paste as shown in FIG. The electric element 12 is mounted. In this way, an infrared detector B as shown in FIG. 5 can be formed using the element mounting board A on which the pyroelectric elements 12 are mounted.

  That is, the infrared detector B is formed to include the element mounting substrate A and a package 17 made of a can package for storing the element mounting substrate A.

  The package 17 includes a metal stem 19 on which the element mounting board A is mounted via a spacer 18 made of an insulating material, and a metal cap 20 fixed to the stem 19 so as to cover the element mounting board A. A plurality of terminal pins 21 that are formed and are electrically connected to predetermined portions of the element mounting board A are provided so as to penetrate the stem 19. The stem 19 is formed in a disc shape, and the cap 20 is formed in a bottomed cylindrical shape with an open rear surface, and the rear surface is closed by the stem 19. The spacer 18, the element mounting board A, and the stem 19 are fixed with an adhesive.

  A rectangular window 22 is formed on the front wall of the cap 20 located in front of the pyroelectric element 12. An infrared lens is used as an optical member for condensing infrared rays on the light receiving surface of the pyroelectric element 12. 23 is arrange | positioned from the inner side of the cap 20 so that the window part 22 may be covered.

  Further, the cap 20 and the stem 19 are formed of a steel plate, and an outer flange portion 25 extending outward from the rear end edge of the cap 20 with respect to the flange portion 24 formed on the peripheral portion of the stem 19. Sealed by welding.

  In the infrared detector B formed as described above, since the opening edge of the recessed portion 5 for thermal insulation is not tilted in the element mounting substrate A housed therein, the mountability of the pyroelectric element 12 is improved. Can be obtained high. In addition, since the resin of the first insulating layer 1 does not ooze out to the inner surface of the recess 5 in the element mounting substrate A, the shape of the recess 5, particularly the cross-sectional area of the recess 5, has not changed before and after the molding. The detection sensitivity of the electric element 12 can be increased.

An example of embodiment of this invention is shown and (a)-(c) is sectional drawing. FIG. 2 shows a step that follows the step shown in FIG. 1, and (a) and (b) are cross-sectional views. It is sectional drawing which shows another example of embodiment of this invention. The other example of a thermoplastic film is shown, (a) (b) is sectional drawing. An example of an infrared detector is shown, (a) is a perspective view, (b) is a perspective view which shows the state which removed the cap from the stem. It shows a method for evaluating fluidity, and is a cross-sectional view when a thermoplastic film alone or a first insulating layer alone in a B-stage state is pressurized. An example of the prior art is shown, and (a) to (c) are cross-sectional views. FIG. 8 shows a step that follows the step shown in FIG. 7, and (a) and (b) are cross-sectional views. It shows another example of the prior art, and (a) to (c) are sectional views. FIG. 4 shows still another example of the prior art, and (a) and (b) are cross-sectional views. FIG. 11 shows a step that follows the step shown in FIG. 10, and (a) and (b) are cross-sectional views.

Explanation of symbols

A element mounting substrate B infrared detector 1 first insulating layer 2 hole 3 metal sheet 4 hole 5 recess 6 thermoplastic film 7 first circuit board 8 second insulating layer 9 element 10 second circuit board 11 release layer 12 focus Electrical element

Claims (6)

  After providing at least one or more penetrating holes in the first insulating layer in the B-stage state, providing a hole in the metal sheet, and laminating the metal sheet on one side of the first insulating layer while matching the hole and hole The first insulating layer is cured by heat and pressure molding, the metal sheet is adhered to the first insulating layer, and a recess for thermal insulation is formed in the hole portion. In this method, a thermoplastic film is laminated on a metal sheet so as to close the hole of the first insulating layer before hot pressing, and the hole is filled with a resin of a thermoplastic film softened by heating and pressing. A method for producing an element mounting board, comprising: removing the resin from the hole by peeling the thermoplastic film after the heat and pressure molding.   Prior to heat and pressure molding, a first circuit board, a B-stage second insulating layer, and a second circuit board on which elements are mounted are laminated in this order on the side opposite to the side on which the metal sheet of the first insulating layer is laminated. Then, the first insulating layer and the second insulating layer are cured by heat and pressure molding, the first circuit substrate is bonded to the first insulating layer, and the first circuit substrate and the element are embedded in the second insulating layer, and The method for manufacturing an element mounting board according to claim 1, wherein the second circuit board is adhered.   3. The method for manufacturing an element mounting substrate according to claim 1, wherein there is at least a state in which the fluidity of the thermoplastic film is higher than the fluidity of the first insulating layer during the heat and pressure molding.   The element mounting substrate manufacturing method according to any one of claims 1 to 3, wherein a thermoplastic film having a release layer on at least a surface facing the hole is used.   An element mounting board manufactured using the method according to claim 1.   An infrared detector, wherein the pyroelectric element is mounted across the recess of the element mounting board according to claim 5 and formed using the element mounting board.

Images