JP2005123493A - Wiring substrate and element packaging substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring substrate and an element packaging substrate wherein warp is restrained. <P>SOLUTION: The difference of linear expansion coefficient α1 between a circuit base material 17 and a frame member 13 in a temperature region lower than a glass transition temperature is made 5 ppm or less, and the difference of linear expansion coefficient α2 between the circuit base material 17 and the frame member 13 in a temperature region higher than the glass transition temperature is made 10 ppm or less. A slit 26 cut in a thickness direction from the other surface of a surface whereto the frame member 13 is stuck is formed in the circuit base material 17. A warp restraining film which is not electrically connected to an element is formed in the other surface 13a of a sticking surface to the circuit base material 17 in the frame member 13. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wiring board having a conductor pattern formed by a transfer method and an element mounting board in which elements are mounted on the wiring board. More specifically, the wiring is designed to suppress warpage caused by a process of being heated. The present invention relates to a substrate and an element mounting substrate.

  In recent years, as electronic devices such as mobile phones, PDAs (Personal Digital Assistants), and notebook computers have become smaller and more sophisticated, high-density mounting of electronic components constituting these devices has become essential. Conventionally, high-density mounting of electronic components has been promoted by finer pitches of component terminals by miniaturization of electronic components, miniaturization of conductor patterns on a wiring board on which electronic components are mounted, and the like.

Conventionally, a transfer method is known as a method for forming a fine pitch conductor pattern on a wiring board. The manufacturing process by this transfer method mainly includes a step of forming a conductor pattern on one surface of the transfer body, a step of bonding the conductor pattern to the insulating layer together with the transfer body, and separating the transfer body and separating the conductor pattern from the insulating layer. And a process of transferring to. As this type of prior art, there is, for example, Patent Document 1.
Japanese Patent Laid-Open No. 10-107445

  An advantage of using the transfer method is that the thickness of the wiring board can be reduced. However, when the wiring board becomes thin, warping is likely to occur due to the influence of heat received in each process. For example, when such a wiring board is used as an interposer board for a semiconductor chip, it becomes difficult to mount the wiring board on a motherboard. Further, if warpage occurs in the sheet-like state before the element is mounted and before the element is divided, it is still difficult to mount the element on the wiring board.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a wiring board and an element mounting board in which warpage is suppressed.

  In the circuit board and the frame member to be bonded to each other, the wiring board of the present invention has a difference in linear expansion coefficient α1 between the circuit base material and the frame member in a temperature region lower than the glass transition temperature of less than 5 ppm. The difference in linear expansion coefficient α2 between the circuit base material and the frame member in a higher temperature region is less than 10 ppm.

  The element mounting board of the present invention is characterized in that an element is mounted on the wiring board. The element is electrically connected to the conductor pattern exposed in the gap of the frame member and mounted on the circuit substrate.

  In the present invention, the linear expansion coefficient of the circuit substrate means the linear expansion coefficient of the insulating layer that constitutes the circuit substrate together with the conductor pattern and functions as a support for the conductor pattern. The insulating layer and the frame member of the circuit substrate are each made of an insulating material, and for example, resin or ceramic can be used.

  By setting it as such a structure, the curvature resulting from the difference of the linear expansion coefficient of a circuit base material and a frame member can be suppressed. The simplest configuration for satisfying the above condition is to use the same material for the circuit substrate and the frame member.

  Moreover, the circuit board and the frame member to be bonded together in the wiring substrate of the present invention, the circuit substrate is formed with a slit cut in the thickness direction from the opposite surface of the surface to which the frame member is attached. It is characterized by being.

  The element mounting board of the present invention is characterized in that an element is mounted on the wiring board. The element is electrically connected to the conductor pattern exposed in the gap of the frame member and mounted on the circuit substrate.

  Strictly speaking, the slit is formed in the insulating layer of the circuit substrate. The insulating layer and the frame member of the circuit substrate are each made of an insulating material, and for example, resin or ceramic can be used.

  When the heating is applied by the slit, the thermal stress is relieved by restraining the free thermal expansion of the insulating layer of the circuit base material, and as a result, the wiring board or the element mounting board is warped. Can be suppressed.

  Further, if the slit is formed at a position away from the gap where the element is disposed, the strength reduction of the element mounting portion can be prevented. In particular, if a plurality of elements are mounted on a sheet-like wiring board and a slit is formed at the dividing position when the wiring board is divided into one element unit or a plurality of units, the final product after the division is There is no slit, and the strength of the product is not reduced.

  In addition, the wiring board of the present invention is characterized in that a warp suppressing film that is not electrically connected to the element is formed on the surface of the frame member opposite to the bonding surface with the circuit base material.

  The element mounting board of the present invention is characterized in that an element is mounted on the wiring board. The element is electrically connected to the conductor pattern exposed in the gap of the frame member and mounted on the circuit substrate.

  The warp suppression film can suppress thermal expansion of the frame member when heated, and as a result, warpage of the wiring board or the element mounting board can be suppressed.

  By using a material having a smaller linear expansion coefficient than the frame member made of insulating resin, for example, a metal film, a ceramic film, etc., as the warp suppression film, the warp suppression film restrains the warpage by restraining the linear expansion of the frame member. be able to. In particular, if the warp suppression film is made of the same material as the conductor pattern formed on the circuit substrate, it can be formed in the same process using the same equipment as the conductor pattern formation, and there is no extra cost or process. The fact that the warp suppressing film and the conductor pattern are made of the same material has the same linear expansion coefficient, and therefore it is possible to suppress the warpage of the wiring board or the element mounting board due to the difference between the linear expansion coefficients of both.

  In the circuit board and the frame member to be bonded to each other, the wiring board of the present invention has a difference in linear expansion coefficient α1 between the circuit base material and the frame member in a temperature region lower than the glass transition temperature of less than 5 ppm. The difference in linear expansion coefficient α2 between the circuit base material and the frame member in the higher temperature region is less than 10 ppm, and the circuit base material is cut in the thickness direction from the surface opposite to the surface on which the frame member is attached. It is characterized in that a slit is formed.

  The element mounting board of the present invention is characterized in that an element is mounted on the wiring board. The element is electrically connected to the conductor pattern exposed in the gap of the frame member and mounted on the circuit substrate.

  With such a configuration, it is possible to suppress warping due to the difference in linear expansion coefficient between the circuit base material and the frame member, and when the circuit base is heated by the slit formed in the circuit base material. The thermal stress can be alleviated by suppressing the free thermal expansion of the insulating layer of the material. As a result, warpage of the wiring board or the element mounting board can be suppressed.

  The simplest configuration for satisfying the above linear expansion coefficient is to use the same material for the circuit substrate and the frame member. In addition, the linear expansion coefficient of a circuit base material means the linear expansion coefficient of the insulating layer which comprises a circuit base material with a conductor pattern and functions as a support body of the conductor pattern. The insulating layer and the frame member of the circuit substrate are each made of an insulating material, and for example, resin or ceramic can be used.

  Strictly speaking, the slit is formed in the insulating layer of the circuit substrate. Further, if the slit is formed at a position away from the gap where the element is disposed, the strength reduction of the element mounting portion can be prevented. In particular, if a plurality of elements are mounted on a sheet-like wiring board and a slit is formed at the dividing position when the wiring board is divided into one element unit or a plurality of units, the final product after the division is There is no slit, and the strength of the product is not reduced.

  In the circuit board and the frame member to be bonded to each other, the wiring board of the present invention has a difference in linear expansion coefficient α1 between the circuit base material and the frame member in a temperature region lower than the glass transition temperature of less than 5 ppm. The difference in linear expansion coefficient α2 between the circuit base material and the frame member in a higher temperature region is less than 10 ppm, and the warp which is not electrically connected to the element on the opposite surface of the frame member to the circuit base material. A suppression film is formed.

  The element mounting board of the present invention is characterized in that an element is mounted on the wiring board. The element is electrically connected to the conductor pattern exposed in the gap of the frame member and mounted on the circuit substrate.

  By adopting such a configuration, it is possible to suppress warpage due to the difference in linear expansion coefficient between the circuit base material and the frame member, and also suppress thermal expansion of the frame member when heated by the warp suppression film. can do. As a result, warpage of the wiring board or the element mounting board can be suppressed.

  The simplest configuration for satisfying the above linear expansion coefficient is to use the same material for the circuit substrate and the frame member. In addition, the linear expansion coefficient of a circuit base material means the linear expansion coefficient of the insulating layer which comprises a circuit base material with a conductor pattern and functions as a support body of the conductor pattern. The insulating layer and the frame member of the circuit substrate are each made of an insulating material, and for example, resin or ceramic can be used.

  By using a material having a smaller linear expansion coefficient than the frame member made of insulating resin, for example, a metal film, a ceramic film, etc., as the warp suppression film, the warp suppression film restrains the warpage by restraining the linear expansion of the frame member. be able to. In particular, if the warp suppression film is made of the same material as the conductor pattern formed on the circuit substrate, it can be formed in the same process using the same equipment as the conductor pattern formation, and there is no extra cost or process. The fact that the warp suppressing film and the conductor pattern are made of the same material has the same linear expansion coefficient, and therefore it is possible to suppress the warpage of the wiring board or the element mounting board due to the difference between the linear expansion coefficients of both.

  Moreover, the circuit board and the frame member to be bonded together in the wiring substrate of the present invention, the circuit substrate is formed with a slit cut in the thickness direction from the opposite surface of the surface to which the frame member is attached. In addition, a warpage suppressing film that is not electrically connected to the element is formed on the surface of the frame member opposite to the surface to be bonded to the circuit substrate.

  The element mounting board of the present invention is characterized in that an element is mounted on the wiring board. The element is electrically connected to the conductor pattern exposed in the gap of the frame member and mounted on the circuit substrate.

  When subjected to heating, the slits can restrain free thermal expansion of the insulating layer of the circuit base material, thereby relieving thermal stress, and the warp suppressing film can reduce the heat of the frame member. Expansion can be suppressed. As a result, warpage of the wiring board or the element mounting board can be suppressed.

  Strictly speaking, the slit is formed in the insulating layer of the circuit substrate. The insulating layer and the frame member of the circuit substrate are each made of an insulating material, and for example, resin or ceramic can be used.

  Further, if the slit is formed at a position away from the gap where the element is disposed, the strength reduction of the element mounting portion can be prevented. In particular, if a plurality of elements are mounted on a sheet-like wiring board and a slit is formed at the dividing position when the wiring board is divided into one element unit or a plurality of units, the final product after the division is There is no slit, and the strength of the product is not reduced.

  By using a material having a smaller linear expansion coefficient than the frame member made of insulating resin, for example, a metal film, a ceramic film, etc., as the warp suppression film, the warp suppression film restrains the warpage by restraining the linear expansion of the frame member. be able to. In particular, if the warp suppression film is made of the same material as the conductor pattern formed on the circuit substrate, it can be formed in the same process using the same equipment as the conductor pattern formation, and there is no extra cost or process. The fact that the warp suppressing film and the conductor pattern are made of the same material has the same linear expansion coefficient, and therefore it is possible to suppress the warpage of the wiring board or the element mounting board due to the difference between the linear expansion coefficients of both.

  In the circuit board and the frame member to be bonded to each other, the wiring board of the present invention has a difference in linear expansion coefficient α1 between the circuit base material and the frame member in a temperature region lower than the glass transition temperature of less than 5 ppm. The difference in linear expansion coefficient α2 between the circuit base material and the frame member in the higher temperature region is less than 10 ppm, and the circuit base material is cut in the thickness direction from the surface opposite to the surface on which the frame member is attached. A slit is formed, and a warp suppressing film that is not electrically connected to the element is formed on the surface of the frame member opposite to the bonding surface with the circuit substrate.

  The element mounting board of the present invention is characterized in that an element is mounted on the wiring board. The element is electrically connected to the conductor pattern exposed in the gap of the frame member and mounted on the circuit substrate.

  With such a configuration, it is possible to suppress warping due to the difference in linear expansion coefficient between the circuit base material and the frame member, and when the circuit base is heated by the slit formed in the circuit base material. It is possible to relieve thermal stress by restraining free thermal expansion of the insulating layer of the material, and it is possible to suppress thermal expansion of the frame member when heated by the warp suppressing film. As a result, warpage of the wiring board or the element mounting board can be suppressed.

  The simplest configuration for satisfying the above linear expansion coefficient is to use the same material for the circuit substrate and the frame member. In addition, the linear expansion coefficient of a circuit base material means the linear expansion coefficient of the insulating layer which comprises a circuit base material with a conductor pattern and functions as a support body of the conductor pattern. The insulating layer and the frame member of the circuit substrate are each made of an insulating material, and for example, resin or ceramic can be used.

  Strictly speaking, the slit is formed in the insulating layer of the circuit substrate. Further, if the slit is formed at a position away from the gap where the element is disposed, the strength reduction of the element mounting portion can be prevented. In particular, if a plurality of elements are mounted on a sheet-like wiring board and a slit is formed at the dividing position when the wiring board is divided into one element unit or a plurality of units, the final product after the division is There is no slit, and the strength of the product is not reduced.

  By using a material having a smaller linear expansion coefficient than the frame member made of insulating resin, for example, a metal film, a ceramic film, etc., as the warp suppression film, the warp suppression film restrains the warpage by restraining the linear expansion of the frame member. be able to. In particular, if the warp suppression film is made of the same material as the conductor pattern formed on the circuit substrate, it can be formed in the same process using the same equipment as the conductor pattern formation, and there is no extra cost or process. The fact that the warp suppressing film and the conductor pattern are made of the same material has the same linear expansion coefficient, and therefore it is possible to suppress the warpage of the wiring board or the element mounting board due to the difference between the linear expansion coefficients of both.

  According to the wiring board of the present invention, the difference in linear expansion coefficient between the circuit base material and the frame member is less than 5 ppm in the temperature region lower than the glass transition temperature, and less than 10 ppm in the temperature region higher than the glass transition temperature, or Form a slit cut in the thickness direction from the opposite surface of the surface on which the frame member is bonded to the circuit base material, or the element on the opposite surface of the frame member to the bonding surface with the circuit base material The warping of the wiring board can be suppressed by forming a warp suppressing film that is not electrically connected to the substrate, or by synergistic effect by combining two or more of them. As a result, the elements can be mounted on the wiring board with high accuracy, and the yield can be improved by reducing the occurrence of defective products.

  According to the element mounting substrate of the present invention, the difference in coefficient of linear expansion between the circuit substrate and the frame member is less than 5 ppm in the temperature region lower than the glass transition temperature, and less than 10 ppm in the temperature region higher than the glass transition temperature, or In the circuit substrate, forming a slit cut in the thickness direction from the opposite surface of the surface on which the frame member is bonded, or on the opposite surface of the bonding surface with the circuit substrate in the frame member, The warpage of the element mounting substrate can be suppressed by forming a warp suppressing film that is not electrically connected to the element, or by a synergistic effect by combining two or more of them. As a result, the generation of defective products can be reduced and the yield can be improved, and this element mounting board can be mounted on other wiring boards (motherboards) without any trouble.

[First Embodiment]
The wiring board and element mounting board according to the present embodiment are obtained as shown in FIGS.

(Step of FIG. 1A)
For example, the transfer layer 1 is manufactured by forming the release layer 3 on one surface of the copper foil 2 having a thickness of about 140 μm. The release layer 3 is composed of two metal layers, for example, a Cr layer having a thickness of about 0.01 μm and a (Ni—Co) layer having a thickness of about 0.15 μm. The Cr layer is deposited on the surface of the copper foil 2 by an electroplating method using the copper foil 2 as a power feeding body, and the (Ni-Co) layer is similarly formed of the Cr layer by an electroplating method using the copper foil 2 as a power feeding body. Deposited on the surface.

  For example, the Cr layer and the (Ni—Co) layer have a characteristic that metal bonding does not occur even at a temperature of about 350 ° C., and therefore can be easily peeled off even when subjected to a hot press in a subsequent process. In this case, peeling is possible at the boundary between the Cr layer and the (Ni—Co) layer.

  In addition to the above-described configuration, the release layer 3 may be, for example, a one-layer structure of a Cr layer, a one-layer structure of a Ni layer, a two-layer structure of a Cr layer and a (Ni—Cr) layer, and a Cr layer and a Ni layer. It may be a two-layer structure.

(Step of FIG. 1B)
A conductor pattern 4 to be transferred to the insulating layer in a later step is formed on the transfer body 1 configured as described above. Specifically, first, a plating resist (not shown) patterned into a desired shape is formed on the surface of the release layer 3.

  Next, the transfer body 1 is dipped in a copper electrolytic bath and connected to the cathode electrode to deposit a copper electroplated film. Thereafter, the plating resist is removed to obtain a conductor pattern 4 made of a copper material.

  In general, compared to a method of removing unnecessary portions of a conductive film by wet etching and patterning (subtractive method), a method of forming a conductive pattern by depositing a conductive film only on necessary portions by electroplating (additive) According to the present embodiment, a fine conductor pattern 4 having a line and space of, for example, 10 μm / 10 μm can be formed with high accuracy.

  Further, the copper foil 2 occupying most of the entire thickness of the transfer body 1 has a small dimensional change due to heat. Therefore, the dimensional accuracy of the fine conductor pattern 4 is suppressed by suppressing the dimensional change of the conductor pattern 4 in the following process. Can be kept stable.

(Steps in FIGS. 2C and D)
In this step, the conductive pattern 4 formed on the transfer body 1 is transferred to the insulating layer 5. In this step, the peeler 6 is also used in addition to the transfer member 1.

  The peeling body 6 is configured by forming a peeling layer 8 made of, for example, two metal layers of a Cr layer and a (Ni—Co) layer on one surface of the copper foil 7. No conductive pattern is formed on the peeled body 6.

  The insulating layer 5 is, for example, a film-like prepreg in which a glass cloth is impregnated with a varnish-like epoxy resin to make a B-stage semi-cured state.

  The conductor pattern 4 is brought into intimate contact with one surface of the insulating layer 5, and the release layer 8 of the release body 6 is in close contact with the other surface, so that the transfer body 1, the insulating layer 5, and the release body 6 are not shown. The pressure is reduced while heating between the hot plates (FIG. 2D).

  As a result, the insulating layer 5 can be made as thin as several μm to several tens of μm, and the thickness can be made uniform over the surface direction. Further, even if the gap between the conductor patterns 4 is very small, the insulating layer 5 can be reliably filled in the gap without any gap. Furthermore, the conductor pattern 4 is embedded in the surface of the insulating layer 5, and a flat surface without unevenness is obtained in which the surfaces of both the conductor pattern 4 and the insulating layer 5 are flush. This contributes to an improvement in device mounting accuracy.

  Further, by controlling the pressurizing pressure and heating temperature according to the material of the insulating layer 5, the thickness of the insulating layer 5 can be adjusted to control electrical characteristics such as characteristic impedance.

  The insulating layer 5 is heated by heat transfer from the transfer body 1 and the release body 6 in a state where both surfaces of the insulating layer 5 are in close contact with the transfer body 1 and the release body 6 which are metals. Therefore, the insulating layer 5 can be heated without any deviation with respect to the surface direction, and thus the thermosetting of the resin can be uniformly promoted with respect to the surface direction to suppress the occurrence of warpage.

  As the insulating layer 5, a material that is not deformed or altered by heating up to a temperature of about 350 ° C. at which the Cr layer and the (Ni—Co) layer constituting the peeling layer 3 described above are not metal-bonded can be used.

  For example, a thermosetting resin such as an epoxy resin, a polyimide resin, a phenol resin, or a bismaleimide / triazine resin can be used. In the case of a thermosetting resin, the insulating layer 5 is softened at a temperature lower than the thermosetting temperature so as to have a desired thickness or the adhesion with the conductor pattern 4 is increased, and then completely heated by further high-temperature heating. Harden.

  Or you may use thermoplastic resins, such as not only a thermosetting resin but liquid crystal polymer, polyetheretherketone, polyetherimide. In this case, the insulating layer 5 can be cured at room temperature without heating and softening the insulating layer 5.

  Further, if another insulating layer having different characteristics from the insulating layer 5 is laminated, the insulating layer may be deformed or deteriorated. In this embodiment, the laminated body to be subjected to hot pressing is insulated. This is not the case with the exception of layer 5, which is metal.

(Step of FIG. 3E)
When the insulating layer 5 is brought into a completely cured state in the hot pressing step, the peeled body 6 is peeled from the insulating layer 5. Specifically, the peeling layer 8 peels at the boundary surface between the Cr layer and the (Ni—Co) layer. For example, the boundary surface is cut off and peeled off. Since the hot pressing is performed at a temperature at which the Cr layer and the (Ni—Co) layer are not metal-bonded, the Cr layer and the (Ni—Co) layer can be easily peeled even when subjected to the thermal stress in the above process. is there.

(Process of FIG. 3F)
In the peeling step, one layer (Ni—Co) layer 8a of the two-layer peeling layer 8 remains on the other surface of the insulating layer 5. After forming a resist pattern (not shown) on the (Ni—Co) layer 8a, openings 9 are selectively formed by wet etching using the resist pattern as a mask.

(Process of FIG. 4G)
Using the (Ni—Co) layer 8a in which the opening 9 is formed as a mask, the portion of the insulating layer 5 facing the opening 9 is, for example, laser etched. Thereby, an interlayer connection hole 10 reaching the conductor pattern 4 is formed in the insulating layer 5. The interlayer connection hole 10 may be formed not only by laser etching but also by wet etching, dry etching, or drilling.

  In this way, a part of the release layer left on the insulating layer 5 at the time of peeling of the peeling body 6 is used as it is as a mask for forming an interlayer connection hole, thereby omitting a step of separately forming a mask for laser etching. Simplification and cost reduction.

(Step of FIG. 4H)
Electroplating is performed in a copper electrolytic bath using the transfer body 1 as a power feeding body, and the interlayer connection hole 10 is filled with a copper material and a panel plating film 11 is formed on the other surface side of the insulating layer 5.

(Step of FIG. 5I)
After forming a resist pattern (not shown) on the plating film 11, the (Ni—Co) layer 8 a and the plating film 11 are patterned by wet etching using the resist pattern as a mask to form the conductor pattern 12.

(Step of FIG. 5J)
Next, the transfer body 1 is peeled from the insulating layer 5, and the conductor pattern 4 is transferred to the insulating layer 5. Specifically, peeling is performed at the boundary surface between the Cr layer and the (Ni—Co) layer in the peeling layer 3. For example, the boundary surface is cut off and peeled off. Since the above-described hot pressing is performed at a temperature at which the Cr layer and the (Ni—Co) layer are not metal-bonded, the Cr layer and the (Ni—Co) layer can be easily peeled even when subjected to the thermal stress in the above process. It is.

(Step of FIG. 5K)
In the peeling process of the transfer body 1, one layer ((Ni—Co) layer 3 a) of the two-layer peeling layer 3 remains on the surface of the insulating layer 5. This (Ni—Co) layer 3a is removed by wet etching using an etching solution that does not dissolve the conductor pattern 4 made of a copper material, and the surface of the conductor pattern 4 is exposed.

  As a result, the fine pitch conductor pattern 4 transferred from the transfer body 1 is formed on one surface of the insulating layer 5 so as to be flat with respect to the insulating layer 5, and the interlayer connection hole 10 is formed on the other surface of the insulating layer 5. The circuit base material 17 in which the conductor pattern 12 electrically connected to the conductor pattern 4 through the conductive material to be filled is formed is obtained.

  The circuit substrate 17 is thinned with a uniform thickness over the surface direction by the above-described hot pressing at the time of transfer of the conductor pattern 4, and the occurrence of warpage is also suppressed. In addition, since the transfer of the conductor pattern 4 and the uniform thinning of the insulating layer 5 are performed in the same process, the number of processes does not increase, and the series of processes described above can be performed using existing equipment. The cost increase related to the preparation of the necessary equipment can be suppressed.

  In addition, since the interlayer connection hole 10 connected to the conductor pattern 4 is formed after the conductor pattern 4 is attached to the insulating layer 5, high-precision alignment with the insulating layer 5 is not necessary when the conductor pattern 4 is attached. is there. Even when the conductive pattern 4 is fine, interlayer connection can be performed with high accuracy by laser etching.

(Steps in FIGS. 6L and M)
An insulating frame member 13 made of, for example, resin or ceramic is thermocompression bonded to the circuit substrate 17 to obtain the wiring board 24. An adhesive layer 14 that is insulative and has low fluidity is formed on one surface of the frame member 13. Further, the frame member 13 is formed with a gap portion 15 penetrating in the thickness direction. The planar dimension of the gap 15 is slightly larger than the planar dimension of the element to be mounted on the conductor pattern 4 a of the circuit substrate 17.

(Step of FIG. 7N)
Of the conductor pattern 4 formed on the circuit substrate 17, the conductor pattern 4 a serving as a joint portion with the element is exposed in the gap portion 15, and the wettability is improved on the conductor pattern 4 a to improve the bondability. Therefore, a bonding material 16 such as tin, nickel, gold, silver, or solder is formed.

(Step of FIG. 7O)
For example, the element 20, which is a semiconductor bare chip, is mounted on the circuit substrate 17 while being positioned in the gap 15. The conductive bump 20 a of the element 20 is electrically connected to the conductor pattern 4 a through the bonding material 16. After the element 20 is mounted, the underfill resin 21 is supplied to the gap 15 to protect the joint between the element 20 and the circuit substrate 17.

(Step of FIG. 8)
Conductive bumps 22 (solder balls, metal plating bumps, metal stud bumps, etc.) functioning as external connection terminals are joined to the conductor pattern 12 exposed on the other surface side of the circuit substrate 17 to form the element mounting substrate 23. can get. By the method as described above, a very thin element mounting substrate 23 having a thickness of 500 μm or less can be obtained.

  In addition, the frame member 13 that surrounds the periphery of the element 20 suppresses warping of the element mounting substrate 23 and improves handling, and other wiring substrates (motherboards) through the conductive bumps 22. It is possible to improve the workability of the mounting process.

  1 to 7 show only one gap portion 15 and one element 20, but actually, FIG. 9 (A is a plan view of the wiring board 24, and B is a side view thereof). As shown in FIG. 10, a plurality of gaps 15 are formed in one frame member 13, and after the frame members 13 are bonded to the circuit substrate 17, the element 20 is placed in each gap 15 as shown in FIG. 10. Is implemented. And it divides | segments by the dividing line shown with a dashed-dotted line in FIG. 10, and the element mounting board | substrate 23 shown in FIG. 8 is obtained. Of course, the unit of division is not limited to one element 20 but may be a plurality of elements 20.

  In the present embodiment, the insulating layer 5 of the circuit base material 17 and the frame member 13 are made of the same material. For example, the material MCL-E-679FG manufactured by Hitachi Chemical Co., Ltd. is used as the insulating layer 5 and the frame member 13.

  By using the same material for the insulating layer 5 and the frame member 13 of the circuit base material 17 to be bonded to each other, the linear expansion coefficient of both of them can be made the same, and the wiring board 24 generated in the process involving the heating, Or the curvature of the element mounting board | substrate 23 with which the element 20 was mounted in it can be suppressed.

  For example, in a state where the circuit base material 17 and the frame member 13 shown in FIG. 9 are bonded to each other and are not divided (step 1), the circuit board 17 18 is likely to be warped upward as shown in FIG.

  In addition, after mounting each element 20 in each gap 15 and after being divided by a one-dot chain line shown in FIG. 10 (step 2), the circuit base 17 19 is likely to be warped upward as shown in FIG.

  Further, each element mounting board 23 after being divided and separated into, for example, one element 20 is subjected to thermal reflow when it is mounted on another wiring board such as a mother board with solder or the like (step 1) 3), a warp that protrudes downward as shown in FIG. 20 tends to occur when the element 20 is placed on the installation surface with the circuit substrate 17 facing down.

  In the present embodiment, as described above, the insulating layer 5 of the circuit base material 17 and the frame member 13 are made of the same material and have the same linear expansion coefficient. It was able to be suppressed to such an extent that it would not become a problem or a problem as a product.

  For example, the coefficient of linear expansion of material MCL-E-679FG manufactured by Hitachi Chemical Co., Ltd. is 16 ppm (xy) in the temperature range lower than the glass transition temperature, and the linear expansion in the temperature range higher than the glass transition temperature. The rate α2 is 3 to 5 ppm (x) and 5 to 7 (y). (X) represents a linear expansion coefficient in one direction in two dimensions, and (y) represents a linear expansion coefficient in a direction orthogonal to the direction (x). (Xy) represents (x) = (y).

  In addition, even if it does not make the linear expansion coefficient of the insulating layer 5 and the frame member 13 of the said circuit base material 17 the same, according to the test which the inventors performed, those both lines in a temperature range lower than a glass transition temperature are used. If the difference in expansion coefficient α1 is less than 5 ppm and the difference in linear expansion coefficient α2 between the two in a temperature range higher than the glass transition temperature is less than 10 ppm, it will not be an obstacle in production or will not cause a problem as a product. It was confirmed that the amount of warpage could be suppressed.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same component as the said 1st Embodiment, and the detailed description is abbreviate | omitted.

  FIG. 11 is a side view of the wiring board according to the present embodiment, and FIG. 12 is an enlarged cross-sectional view of the main part thereof. Also in the present embodiment, the wiring board 24 and the element mounting board 23 are obtained by the same process as in the first embodiment. However, in the present embodiment, the frame member 13 is formed on the insulating layer 5 of the circuit substrate 17. The slit 26 cut | disconnected in the thickness direction from the surface opposite to the surface where No. was affixed is formed.

  The slit 26 is formed to a depth not reaching the frame member 13 with a cutting tool such as a blade or a laser, for example. If the slit 26 is kept at a depth that does not reach the frame member 13 (for example, about half to about 4/5 of the circuit base material 17), a decrease in strength due to the slit 26 can be suppressed. Moreover, the slit 26 is formed along the dividing line shown with a dashed-dotted line in FIG. Or you may form along only the dividing line of one direction among the said dividing lines orthogonally crossed.

  By forming such a slit 26, the free thermal expansion of the wiring board 24 or the element mounting board 23 is restrained during the process involving heating described above, and the thermal stress is relieved. As a result, warpage of the wiring board 24 or the element mounting board 23 can be suppressed.

  In addition, the slit 26 is formed along a dividing line that is a region deviated from the gap portion 15 where the element 20 is disposed. Therefore, the slit 26 does not remain in the final product state, and the slit 26 allows the product to be formed. There is no reduction in strength.

  In addition, even if the slit 26 is formed at a position corresponding to the space 15 below, the warp suppressing effect can be obtained.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same component as the said 1st Embodiment, and the detailed description is abbreviate | omitted.

  FIG. 13 is a plan view of the wiring board 24 according to the present embodiment. Also in the present embodiment, the wiring board 24 and the element mounting board 23 are obtained by the same process as in the first embodiment. However, in the present embodiment, the bonding surface of the frame member 13 with the circuit base material 17 is obtained. A warp suppressing film 27 is formed on the opposite surface 13a (see also FIG. 6).

  The warp suppressing film 27 is formed in a frame shape with a solid pattern on the outer edge of the frame member 13. The warp suppressing film 27 is made of the same copper material as that of the conductor pattern 4 and is formed, for example, by selectively etching unnecessary portions after pattern plating, panel plating, or pasting of a solid copper foil. Further, the warp suppressing film 27 is not physically or electrically connected to the conductor patterns 4 and 12 formed on the circuit substrate 17.

  By forming the warp suppressing film 27 from a copper material that is difficult to thermally expand in this way, the thermal expansion of the wiring substrate 24 or the element mounting substrate 23 can be suppressed during the above-described process involving heating. As a result, warpage of the wiring board 24 or the element mounting board 23 can be suppressed.

  Further, the warp suppressing film 27 is not a single line, and cuts 27a (for example, two per side) are formed in some places, so that the thermal stress of the warp suppressing film 27 can be relieved, whereby the wiring substrate 24 or The element mounting substrate 23 can be made more difficult to warp.

  The warp suppression film is not limited to a solid pattern, and may be a warp suppression film 28 having a mesh pattern as shown in FIG. The warp suppressing film 28 is also formed with a cut 28a for thermal stress relaxation.

  In addition, as shown in FIG. 15, a warpage suppressing film 29 may be formed so as to surround the periphery of each gap portion 15. When the warp suppressing film 29 shown in FIG. 15 and the warp suppressing film 27 shown in FIG. 13 are combined, almost the entire surface of the frame member 13 is covered with the warp suppressing films 27 and 29.

  Alternatively, as shown in FIG. 16, the warpage suppressing films 30 may be formed only at the four corners around the edge of each gap portion 15. When the area of the warp suppressing film 29 shown in FIG. 15 is “100”, the area of the warp suppressing film 30 shown in FIG. 16 is “30”, for example.

  Furthermore, as shown in FIG. 17, a warp suppressing film 31 may be formed between the warp suppressing films 30 at the four corners shown in FIG. If the area of the warp suppressing film 29 shown in FIG. 15 is “100”, the area of the warp suppressing film 31 shown in FIG. 17 is “60”, for example.

  Since any of the warp suppressing films 27 to 31 is made of the same copper material as that of the conductor patterns 4 and 12 formed on the circuit substrate 17, the line between the warp suppressing films 27 to 31 and the conductor patterns 4 and 12 is used. The expansion coefficient can be made the same, which also contributes to the suppression of the warpage of the wiring board 24 or the element mounting board 23. The warp suppressing films 27 to 31 are not limited to a copper material, and other metal materials and ceramic materials can be used to suppress the warping of the frame member 13 as long as the material has a smaller linear expansion coefficient than the resin material that is the material of the frame member 13. It is valid.

  Of course, even when the warp suppressing films 27 to 31 shown in FIGS. 13 to 17 are combined, the warp suppressing effect can be obtained.

  Next, the results of the comparison test of the warpage amount for the comparative example and Examples 1 to 4 shown in Table 1 will be described.

  As shown in FIGS. 9 and 10, the configuration of the comparative example has a plan dimension of 125 mm × 125 mm square, and 6 × 6 = 36 gaps 15 are formed on the wiring board 24 having a thickness of 200 μm. After mounting an element (semiconductor bare chip) 20 having a thickness of 17.5 mm × 17.5 mm and a thickness of 350 μm in each of the gaps 15, it is divided by a one-dot chain line in FIG. The element mounting substrate 23 (thickness: 500 μm) for each element 20 is obtained.

  As shown in Table 1, in the comparative example, the frame member 13 uses a material MCL-BE-67G manufactured by Hitachi Chemical Co., Ltd., and the circuit substrate 17 uses a material MCL-E-679FG manufactured by Hitachi Chemical Co., Ltd. They have different linear expansion coefficients.

  Each of the frame member 13 and the circuit substrate 17 in the comparative example contains one glass cloth (7 μm yarn made of E glass).

  In the comparative example, the slit 26 shown in the second embodiment and the warp suppressing films 27 to 31 shown in the third embodiment are not formed.

  Example 1 differs from the comparative example only in that the same material MCL-E-679FG manufactured by Hitachi Chemical Co., Ltd. is used for the frame member 13 and the circuit substrate 17. That is, the linear expansion coefficient of both the frame member 13 and the circuit base material 17 is the same.

  The second embodiment is different from the first embodiment only in that two glass cloths having a thickness approximately half that of the glass cloth put in the frame member 13 of the first embodiment are put on the frame member 13 in an overlapping manner. Thereby, the rigidity of the frame member 13 is improved as compared with the first embodiment, and the warpage is suppressed.

  Example 3 differs from Example 1 only in that the slit 26 shown in the second embodiment is formed in the circuit substrate 17. In addition, the slit 26 is formed along only the dividing line of one direction among the dividing lines orthogonal to each other shown by a one-dot chain line in FIG.

  Example 4 differs from Example 1 only in that the warp suppressing films 27 to 31 shown in the third embodiment are formed on the frame member 13. In Example 4, as shown in Table 3, nine combinations of warpage suppressing films 27 to 31 were produced.

  The results for the comparative example and Examples 1 to 3 are shown in Table 2.

  Stage 1 after the frame member 13 and the circuit substrate 17 are bonded together (the state shown in FIG. 9), and the element 20 is mounted in each gap portion 15 and divided by the one-dot chain line shown in FIG. Stage 2 after each element 20 is made to be an element mounting board 23 and stage 2 after this stage 2 after reflow heating for soldering each element mounting board 23 to another wiring board or the like The amount of warpage was measured for each of the three.

  If the circuit board 17 is placed on a horizontal installation surface and warps upwards, the lift amount of the most lifted part among the nine points determined in advance is used as the warp amount. In the case where the projection warps downward, the lift amount at the most lifted position among the four diagonal positions is adopted as the warp amount. The warpage amount in the comparative example is “1”, and the warpage amounts of the first to third embodiments are shown.

  As is clear from this result, in Examples 1 to 3, the amount of warpage is reduced compared to the comparative example in each of the stages 1, 2, and 3. In particular, in stage 1 of Example 3, the amount of warpage is significantly reduced.

  The results for Example 4 are shown in Table 3.

  In Table 3, the combination pattern 1 is a case where only the warp suppression film 29 shown in FIG. 15 is formed, and the combination pattern 2 is a case where the warp suppression film 28 shown in FIG. 14 and the warp suppression film 29 shown in FIG. 15 are formed. Yes, the combination pattern 3 is the case where the warp suppressing film 27 shown in FIG. 13 and the warp suppressing film 30 shown in FIG. 16 are formed, and the combined pattern 4 is the warp suppressing film 27 shown in FIG. 13 and the warp suppressing film shown in FIG. The combination pattern 5 is a case where the warp suppressing film 27 shown in FIG. 13 and the warp suppressing film 29 shown in FIG. 15 are formed, and the combined pattern 6 is the warp suppressing film 30 shown in FIG. , 31 is formed, and the combination pattern 7 is a case where only the warp suppressing film 30 shown in FIG. Is the case where the warp suppressing film 28 shown in FIG. 14 and the warp suppressing films 30 and 31 shown in FIG. 17 are formed, and the combination pattern 9 forms the warp suppressing film 28 shown in FIG. 14 and the warp suppressing film 30 shown in FIG. This is the case.

  As is apparent from Table 3, the warpage amount is reduced with respect to the combination patterns 1 to 5 of the warp suppression film as compared with the comparative example (in the case of no warpage suppression film in Table 3). In addition, about the combination patterns 6-9, although only preparation was performed and the curvature amount was not measured, the reduction of curvature amount was seen compared with the comparative example by visual observation.

  As mentioned above, although each embodiment of this invention was described, of course, this invention is not limited to these, A various deformation | transformation is possible based on the technical idea of this invention.

  Combination of the first to third embodiments (combination of the first and second embodiments, combination of the first and third embodiments, combination of the second and third embodiments, first and second In the configuration of the third embodiment), the warp suppressing effect as described above can be obtained.

  A film-like resin was used as the insulating layer 5 of the circuit substrate 17, but instead, a paste-like resin was applied to the surface of the transfer body 1 on which the conductor pattern 4 was formed, and then the resin The release layer 8 of the release body 6 is brought into close contact with the surface, and a paste-like resin is sandwiched between the transfer body 1 and the release body 6 and heated to obtain an insulating layer that supports the conductor pattern 4. Also good.

  Further, when the insulating layer 5 is narrowed by the transfer body 1 and the release body 6, it is not limited to being sandwiched between plates, but may be sandwiched between rollers.

  The transfer body 1 is not limited to a metal, and may be glass, a semiconductor wafer, or the like, and a release layer or a conductor pattern formed on the transfer body 1 may be formed by an electroless plating method or a sputtering method.

  In addition, the manufacture of the wiring board having a configuration in which the circuit base material and the frame member are bonded together and the element mounting board on which the element is mounted are not limited to the steps shown in FIGS. An insulating layer is formed on the transfer body so as to fill the space between the conductor patterns to form a circuit base, and after the frame member is attached to the circuit base and the element is mounted, the transfer body is peeled off. May be. Alternatively, the element may be mounted after the transfer body is peeled off.

  The element is not limited to a semiconductor bare chip, but may be a semiconductor package component, a light emitting element, a chip resistor, a chip capacitor, or the like.

  Moreover, not only the single side | surface of a circuit base material but the structure where an element is mounted on both surfaces may be sufficient.

It is a manufacturing process sectional view of a wiring board concerning a 1st embodiment of the present invention. FIG. 2 is a manufacturing process cross-sectional view subsequent to FIG. 1. FIG. 3 is a manufacturing process sectional view following FIG. 2; FIG. 4 is a sectional view of the manufacturing process subsequent to FIG. 3. FIG. 5 is a sectional view of the manufacturing process following FIG. 4. FIG. 6 is a cross-sectional view of an element mounting board manufacturing process performed subsequent to FIG. 5. FIG. 7 is a manufacturing process sectional view following FIG. 6; It is sectional drawing of the element mounting board | substrate which concerns on the 1st Embodiment of this invention. A is a plan view of a wiring board according to the first embodiment of the present invention, and B is a side view thereof. A is a top view of the element mounting board | substrate (before division | segmentation) which concerns on the 1st Embodiment of this invention, B is the side view. It is a side view of the wiring board which concerns on the 2nd Embodiment of this invention. It is an expanded sectional view of the principal part in FIG. It is a top view of the wiring board concerning a 3rd embodiment of the present invention. It is a top view of the wiring board by a modification. It is an enlarged plan view of the principal part of the wiring board by a modification. It is an enlarged plan view of the principal part of the wiring board by a modification. It is an enlarged plan view of the principal part of the wiring board by a modification. It is a schematic diagram which shows the tendency of the direction of the curvature of a wiring board after bonding a circuit base material and a frame member. It is a schematic diagram which shows the tendency of the direction of the curvature of the element mounting board | substrate after being divided | segmented. It is a schematic diagram which shows the tendency of the direction of the curvature of an element mounting board | substrate after receiving the thermal reflow at the time of mounting on another wiring board etc. after a division | segmentation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Transfer body, 2 ... Copper foil, 3 ... Release layer, 4 ... Conductor pattern, 5 ... Insulating layer, 6 ... Release body, 7 ... Copper foil, 8 ... Release layer, 10 ... Interlayer connection hole, 12 ... Conductor pattern , 13 ... frame member, 14 ... adhesive layer, 15 ... gap portion, 17 ... circuit substrate, 20 ... element, 22 ... external terminal, 23 ... element mounting substrate, 24 ... wiring board, 26 ... slit, 27 to 31 ... Warpage suppression membrane.

Claims (30)

A circuit substrate on which the conductor pattern transferred from the transfer body is formed on the surface of the insulating layer;
A frame member having a gap for element mounting is a wiring board that is bonded to the gap to expose the conductor pattern,
The difference in linear expansion coefficient α1 between the circuit base material and the frame member in a temperature region lower than the glass transition temperature is less than 5 ppm, and the linear expansion between the circuit base material and the frame member in a temperature region higher than the glass transition temperature. The wiring board, wherein the difference in rate α2 is less than 10 ppm. A circuit substrate on which the conductor pattern transferred from the transfer body is formed on the surface of the insulating layer;
A frame member having a gap for element mounting is a wiring board that is bonded to the gap to expose the conductor pattern,
The circuit board is provided with a slit formed in a thickness direction from a surface opposite to the surface to which the frame member is attached. The wiring board according to claim 2, wherein the slit is formed at a position away from the gap. A circuit substrate on which the conductor pattern transferred from the transfer body is formed on the surface of the insulating layer;
A frame member having a gap for element mounting is a wiring board that is bonded to the gap to expose the conductor pattern,
A wiring board, wherein a warp suppressing film that is not electrically connected to the element is formed on a surface of the frame member opposite to a bonding surface with the circuit base material. The wiring board according to claim 4, wherein the warpage suppressing film is made of the same material as the conductor pattern. A circuit substrate on which the conductor pattern transferred from the transfer body is formed on the surface of the insulating layer;
A frame member having a gap for element mounting is a wiring board that is bonded to the gap to expose the conductor pattern,
The difference in linear expansion coefficient α1 between the circuit base material and the frame member in a temperature region lower than the glass transition temperature is less than 5 ppm, and the linear expansion between the circuit base material and the frame member in a temperature region higher than the glass transition temperature. The difference in rate α2 is less than 10 ppm,
The circuit board is provided with a slit formed in a thickness direction from a surface opposite to the surface to which the frame member is attached. The wiring board according to claim 6, wherein the slit is formed at a position away from the gap. A circuit substrate on which the conductor pattern transferred from the transfer body is formed on the surface of the insulating layer;
A frame member having a gap for element mounting is a wiring board that is bonded to the gap to expose the conductor pattern,
The difference in linear expansion coefficient α1 between the circuit base material and the frame member in a temperature region lower than the glass transition temperature is less than 5 ppm, and the linear expansion between the circuit base material and the frame member in a temperature region higher than the glass transition temperature. The difference in rate α2 is less than 10 ppm,
In the frame member, a warp suppressing film that is not electrically connected to the element is formed on a surface opposite to a bonding surface with the circuit base material. The wiring board according to claim 8, wherein the warpage suppressing film is made of the same material as the conductor pattern. A circuit substrate on which the conductor pattern transferred from the transfer body is formed on the surface of the insulating layer;
A frame member having a gap for element mounting is a wiring board that is bonded to the gap to expose the conductor pattern,
The circuit substrate is formed with a slit cut in the thickness direction from the surface opposite to the surface to which the frame member is attached,
In the frame member, a warp suppressing film that is not electrically connected to the element is formed on a surface opposite to a bonding surface with the circuit base material. The wiring board according to claim 10, wherein the slit is formed at a position away from the gap. The wiring board according to claim 10, wherein the warpage suppressing film is made of the same material as the conductor pattern. A circuit substrate on which the conductor pattern transferred from the transfer body is formed on the surface of the insulating layer;
A frame member having a gap for element mounting is a wiring board that is bonded to the gap to expose the conductor pattern,
The difference in linear expansion coefficient α1 between the circuit base material and the frame member in a temperature region lower than the glass transition temperature is less than 5 ppm, and the linear expansion between the circuit base material and the frame member in a temperature region higher than the glass transition temperature. The difference in rate α2 is less than 10 ppm,
The circuit substrate is formed with a slit cut in the thickness direction from the surface opposite to the surface to which the frame member is attached,
In the frame member, a warp suppressing film that is not electrically connected to the element is formed on a surface opposite to a bonding surface with the circuit base material. The wiring board according to claim 13, wherein the slit is formed at a position deviated from the gap. The wiring board according to claim 13, wherein the warpage suppressing film is made of the same material as the conductor pattern. A circuit substrate in which a conductor pattern transferred from a transfer body is formed on the surface of an insulating layer is bonded to a frame member having a gap, and the element is mounted by being electrically connected to the conductor pattern in the gap. An element mounting board,
The difference in linear expansion coefficient α1 between the circuit base material and the frame member in a temperature region lower than the glass transition temperature is less than 5 ppm, and the linear expansion between the circuit base material and the frame member in a temperature region higher than the glass transition temperature. The element mounting substrate, wherein the difference in the rate α2 is less than 10 ppm. A circuit substrate in which a conductor pattern transferred from a transfer body is formed on the surface of an insulating layer is bonded to a frame member having a gap, and the element is mounted by being electrically connected to the conductor pattern in the gap. An element mounting board,
The element mounting board, wherein the circuit substrate is formed with a slit cut in a thickness direction from a surface opposite to the surface to which the frame member is attached. The element mounting board according to claim 17, wherein the slit is formed at a position deviated from the gap. A circuit substrate in which a conductor pattern transferred from a transfer body is formed on the surface of an insulating layer is bonded to a frame member having a gap, and the element is mounted by being electrically connected to the conductor pattern in the gap. An element mounting board,
An element mounting substrate, wherein a warp suppressing film that is not electrically connected to the element is formed on the surface of the frame member opposite to the bonding surface with the circuit base material. The element mounting board according to claim 19, wherein the warpage suppressing film is made of the same material as the conductor pattern. A circuit substrate in which a conductor pattern transferred from a transfer body is formed on the surface of an insulating layer is bonded to a frame member having a gap, and the element is mounted by being electrically connected to the conductor pattern in the gap. An element mounting board,
The difference in linear expansion coefficient α1 between the circuit base material and the frame member in a temperature region lower than the glass transition temperature is less than 5 ppm, and the linear expansion between the circuit base material and the frame member in a temperature region higher than the glass transition temperature. The difference in rate α2 is less than 10 ppm,
The element mounting board, wherein the circuit substrate is formed with a slit cut in a thickness direction from a surface opposite to the surface to which the frame member is attached. The element mounting substrate according to claim 21, wherein the slit is formed at a position deviated from the gap. A circuit substrate in which a conductor pattern transferred from a transfer body is formed on the surface of an insulating layer is bonded to a frame member having a gap, and the element is mounted by being electrically connected to the conductor pattern in the gap. An element mounting board,
The difference in linear expansion coefficient α1 between the circuit base material and the frame member in a temperature region lower than the glass transition temperature is less than 5 ppm, and the linear expansion between the circuit base material and the frame member in a temperature region higher than the glass transition temperature. The difference in rate α2 is less than 10 ppm,
An element mounting substrate, wherein a warp suppressing film that is not electrically connected to the element is formed on a surface of the frame member opposite to a bonding surface with the circuit base material. The element mounting board according to claim 23, wherein the warpage suppressing film is made of the same material as the conductor pattern. A circuit substrate in which a conductor pattern transferred from a transfer body is formed on the surface of an insulating layer is bonded to a frame member having a gap, and the element is mounted by being electrically connected to the conductor pattern in the gap. An element mounting board,
The circuit substrate is formed with a slit cut in the thickness direction from the surface opposite to the surface to which the frame member is attached,
An element mounting substrate, wherein a warp suppressing film that is not electrically connected to the element is formed on a surface of the frame member opposite to a bonding surface with the circuit base material. The element mounting substrate according to claim 25, wherein the slit is formed at a position deviated from the gap. 26. The element mounting board according to claim 25, wherein the warpage suppressing film is made of the same material as the conductor pattern. A circuit substrate in which a conductor pattern transferred from a transfer body is formed on the surface of an insulating layer is bonded to a frame member having a gap, and the element is mounted by being electrically connected to the conductor pattern in the gap. An element mounting board,
The difference in linear expansion coefficient α1 between the circuit base material and the frame member in a temperature region lower than the glass transition temperature is less than 5 ppm, and the linear expansion between the circuit base material and the frame member in a temperature region higher than the glass transition temperature. The difference in rate α2 is less than 10 ppm,
The circuit substrate is formed with a slit cut in the thickness direction from the surface opposite to the surface to which the frame member is attached,
An element mounting substrate, wherein a warp suppressing film that is not electrically connected to the element is formed on a surface of the frame member opposite to a bonding surface with the circuit base material. The element mounting substrate according to claim 28, wherein the slit is formed at a position deviated from the gap. The element mounting board according to claim 28, wherein the warpage suppressing film is made of the same material as the conductor pattern.

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