JP2012038790A - Electronic member and electronic component and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic member which permits joining material to be supplied in a fine pitch, exhibits high reliability, and is capable of electrical connection.SOLUTION: When copper oxide is reduced to copper, a number of nuclei of metallic copper are formed within copper oxide, so that, when reduced, the original outer shape is retained while being stripped of all contents, and that the generated copper has an increased curvature. By making use of this turn-into-fine particles mechanism, joining is made possible even when copper oxide is supplied in fine layer form, not in particulate form. Also, by using copper with high migration resistance, joining with higher reliability than possible with conventional silver is obtainable. The present invention involves an electronic member which includes electrodes to input/output electric signals or connection terminals for connecting electric signals, the electrodes or the connection terminals having their outermost surfaces comprised of a copper oxide layer.

Description

  The present invention relates to an electronic member on the premise that electrical bonding between electronic members (for example, bonding between a semiconductor element and a circuit member) is performed, and relates to an electronic component mounted with the electronic member and a mounting method thereof. Hereinafter, semiconductor elements, circuit members, and the like are collectively referred to as electronic members.

  In recent years, there has been an increasing demand for multi-functionality, high speed, lightness, thinness and miniaturization, including mobile devices. In order to achieve this, it is important to reduce the pitch and height of electrodes for inputting and outputting electrical signals.

  Furthermore, since heat generation per unit area and unit volume increases with high-density mounting, it is important to improve heat dissipation. At the same time, it is important to reduce the resistance of the joint as the electrode area decreases. On the other hand, an organic substrate or the like has been used for the peripheral member, and it is desired to lower the bonding temperature corresponding to the organic substrate.

  Examples of connection techniques for electrically bonding electrodes between a plurality of electronic members include bonding using a conductive adhesive and solder, and metal pressure welding (bonding such as gold bumps). In contrast to these preceding connection technologies, there has been reported a technology capable of realizing a joint having heat dissipation, heat resistance and electrical resistance lower than that of solder or silver paste by using silver oxide particles ( For example, refer nonpatent literature 1).

  The joining technique using silver oxide is a technique in which silver oxide particles are reduced at a low temperature by a reducing atmosphere and a reducing agent, and the joining portion is composed of silver having low resistance and high heat dissipation (Non-Patent Document 1). Since this technique does not contain a binder as in the case of a conductive adhesive, metal bonding can be obtained with respect to the mating electrode to be bonded, so that it is possible to provide a bonded portion with excellent heat dissipation.

  When a composition composed of silver oxide and a reducing agent is heated, silver fine particles having a particle size of 100 nm or less with a high sintering ability even at a low temperature are generated. The organic components contained in the composition are decomposed and removed by this heat treatment, so that the generated silver particles are sintered with each other and between the silver particles and the electrodes, and the electrodes of the electronic components are joined by a silver network. Electronic parts are completed. By using this technique, bonding at a temperature lower than the melting point of the conventional bulk metal, for example, 250 ° C. or less is possible. Furthermore, it becomes a joining layer excellent in heat dissipation characteristics by being composed of metallic silver. However, in order to obtain a good bonded state, a pressure application step is required together with the heating step.

  As for the supply of the particulate silver oxide bonding material listed above, there is a method in which a reducing agent for reducing silver oxide to silver at a low temperature is added, applied to a plate material in a paste state, and inserted. . According to this method, since it is difficult to supply a fine pitch by printing the paste material, reliable bonding cannot be performed. On the other hand, in order to solve this, there is a technique in which the outermost surface of the electrode for inputting / outputting an electric signal or the connecting terminal for connecting the electric signal is a silver oxide layer.

Materials Transactions, Vol.49, No.12 (2008) pp.2875 to 2880

  In the joining in which the electrode surface is made of silver oxide, silver particles having a particle diameter of 100 nm or less are generated during the reduction, thereby enabling joining at a low temperature. However, as a result of diligent experiments regarding the technique of joining the above materials by the present inventors, it has been found that there are the following problems.

  It was found that at a fine pitch of 100 μm or less, silver cannot be reliably bonded by migration.

  Next, a paste material was dip coated on the Au bumps of the LSI chip arranged at a fine pitch, and placed on a printed board having a solder resist between the connection terminals. There was no problem at the stage of installation. However, as a result of pressurizing at the time of bonding, the paste material has good fluidity, so that the bonding material spreads beyond the resist range, and the electrodes are short-circuited after bonding.

  Moreover, the drying process was performed before joining and the spreading | diffusion of the joining material by pressurization was prevented. However, the bonding layer in the region applied to the side surface of the bump is bonded without applying pressure, and the bonding strength to the Au bump cannot be obtained. After the bonding, the bonding layer peels off, and the peeled bonding layer contacts the adjacent electrode. A short circuit appeared.

  The present invention has been made in view of such problems. An object of the present invention is to provide a highly reliable electronic member that can supply a bonding material at a fine pitch of 100 μm or less and can be electrically connected with low resistance.

  The inventors of the present invention have confirmed with a reflection scanning electron microscope that when copper oxide is reduced from copper oxide, even if it is a layered copper oxide particle having a small curvature, the curvature of copper produced by reduction is large. This is because the phenomenon that the volume of the copper oxide 101 is reduced by reducing the copper oxide 101 does not shrink in a similar shape as shown in FIG. 1 (a), but in the copper oxide as shown in FIG. 1 (b). This is because a large number of nuclei of metallic copper 102 are formed, and they are reduced to form while maintaining the original shape.

  It has been found that by using this micronization mechanism, copper oxide can be joined using copper oxide formed by providing a dense layer rather than particles. Thus, it becomes possible to solve the problem caused by forming a paste by bonding using copper oxide formed in layers.

  Furthermore, by using copper having higher migration resistance than silver, it is possible to maintain high reliability even at a fine pitch of 100 μm or less.

  Thus, in order to achieve the above object, the present invention provides an electronic member characterized in that an outermost surface of an electrode for inputting / outputting an electric signal or a connecting terminal for connecting an electric signal is a copper oxide layer. .

  The electronic member is characterized in that a copper layer is formed on the outermost surface of the electrode or the connection terminal, and the copper layer is oxidized to form a copper oxide layer as a whole or a part of the copper layer. It can produce with the manufacturing method of the electronic member to make.

  Further, a step of supplying a reducing agent to the copper oxide layer of the electronic member and applying heating at 50 ° C. to 400 ° C. at least to the bonding surface, and at least zero to the bonding surface when the copper oxide is reduced to metallic copper Alternatively, an electronic component mounting method is provided in which electrodes are electrically joined by applying a pressure smaller than 100 MPa.

  By the above technique, one or more connection terminals provided on the circuit board are electronic components in which one or more electrode terminals provided on the electronic member are electrically bonded via a bonding layer, The bonding layer is mainly composed of sintered copper having a crystal grain size of 1000 nm or less, and the entire surface or part of the electrode surface other than the bonding layer is a roughened layer of metallic copper. Can provide electronic parts.

In the present invention, a technique is employed in which all or part of the Cu metallization is oxidized to a copper oxide layer.
As a result, the pitch interval at which the Cu metallized electrode can be formed becomes the pitch interval that can be bonded according to the present invention, so that an electronic member that has a very small decrease in pitch interval due to the bonding material supply method is obtained. Further, by using copper having high migration resistance, high reliability is possible even at a fine pitch of 100 μm or less. Furthermore, since the joint is made of metallic copper, the heat dissipation, heat resistance, and electrical resistance of the joint can be reduced. Thus, by using the present invention, it is possible to bond copper oxide bonding technology that can be bonded at a low temperature, which was impossible in the past, and can realize high heat radiation and high heat resistance with low reliability. Fine pitch and thin supply is possible, and high-precision and high-density mounting is possible.

It is the cross-sectional schematic diagram which showed the behavior in which copper oxide reduces and produces | generates a copper particle. It is the cross-sectional schematic diagram which showed the electronic member which has a silver oxide layer on the surface which is an example which concerns on this invention. 1 is a schematic cross-sectional view showing a component built-in type multilayer wiring board as an example according to the present invention. 1 is a schematic cross-sectional view showing a component built-in type multilayer wiring board as an example according to the present invention. 1 is a schematic cross-sectional view showing a component built-in type multilayer wiring board as an example according to the present invention. It is the cross-sectional schematic diagram which showed the laminated chip which is one example which concerns on this invention.

  One example of the present invention will be described with reference to FIGS. In FIG. 2A, a copper oxide layer 801 is provided on the surface of the metallized layer 802 of the passive component 803.

  As shown in FIG. 3, it was found that a copper oxide layer serving as a bonding material can be provided at a high density. By joining the passive component 803 to the substrate shown in FIG. 3 by the mounting method described above, an electronic component having the sintered copper layer 813 shown in FIG. 3 at the joint can be provided. Moreover, the sintered copper layer which is not pressurized at the time of joining becomes a roughened layer. In the present invention, the copper oxide layer serving as the bonding material is not fluid like the paste material, and has a certain strength against the underlying metallization, and further does not melt during bonding like the solder material, There is no spread of the bonding material (conductive part) due to heating or pressing during bonding. In addition, since metal bonding is obtained with no pressure per bonding surface or low pressure of 0.1 to 20 MPa, plastic deformation in the direction parallel to the bonding surface of the bump can be reduced as compared with the pressure bonding method. In this way, the electronic component is hardly reduced in pitch interval when mounting an electronic member, which was a problem of the conventional method.

  The invention using this characteristic and the improvements will be described below.

  By supplying copper oxide in layers instead of particles, a certain strength can be imparted to the supply surface. Thus, by giving the strength between the bonding material before bonding and the base, it is possible to prevent impact resistance and scattering of the bonding material during bonding. Further, by leaving a part of the Cu metallization after the processing from the Cu metallized layer to the copper oxide layer, that is, by making the base of the copper oxide layer Cu metallized, an adhesion force of 5 MPa or more is provided between the copper oxide layer and the base. Can be granted.

  In joining using copper oxide, joining is performed by sintering of copper particles generated during reduction. However, volume reduction occurs when reducing from copper oxide to metallic copper. For this reason, as the film thickness is increased, pressure is applied at the time of bonding so that the film is compressed in a direction perpendicular to the bonding surface and becomes dense. When the thickness of the copper oxide layer exceeded about 100 nm, a rapid increase in strength was observed. Therefore, the thickness of the copper oxide layer serving as the bonding layer is preferably 100 nm or more. However, if it exceeds 10 μm, it takes a long time to form copper oxide, and the time for reduction at the time of bonding also becomes longer, which is not preferable. Therefore, the thickness of the copper oxide layer serving as the bonding layer is preferably 10 μm or less.

  The electrode surfaces of the electronic parts to be joined have difficulty in sintering with copper particles having a small curvature and reduced from copper oxide as compared with copper particles. As described above, since the copper particles produced by reduction from copper oxide reflect the outer shape of copper oxide before reduction, it is advantageous that the radius of curvature of copper oxide before reduction is smaller. The curvature of copper oxide can be controlled by the oxidation treatment conditions. Moreover, it is preferable to control the curvature radius of the copper oxide layer to be 1 μm or less on the surface of the copper oxide layer so that the curvature of the copper particles to be generated becomes nanometer-sized particles. Furthermore, when two or more electronic members are stacked and pressed and joined, there is a frictional resistance on the surface, so that it is possible to suppress slipping of components when pressed.

  Materials that function as a reducing agent for the copper oxide layer include organic substances and a reducing gas. As the kind of organic substance, one or more kinds of organic substances selected from carboxylic acids, alcohols, and amines are preferable. Note that “class” includes ions, complexes, and the like derived from cases where organic substances are chemically bonded to metals. Moreover, the organic substance which coat | covers the metal particle with a particle size of nanometer size is also included. However, it is desirable to avoid organic substances containing sulfur and halogen elements because the elements may remain in the bonding layer during the bonding period and cause corrosion.

  Examples of carboxylic acids include acetic acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, myristolein Acid, palmitoleic acid, oleic acid, elaidic acid, erucic acid, nervonic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid, succinic acid, oxalic acid, malonic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, Malic acid, adipic acid, citric acid, benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, 2,4-hexadiyne carboxylic acid, 2,4-heptadiyne carboxylic acid, 2,4-octadiyne carboxylic acid, 2,4-decadiyne carboxylic acid, 2,4-dodecadiyne carbo Acid, 2,4-tetradecadiyne carboxylic acid, 2,4-pentadecadiyne carboxylic acid, 2,4-hexadecadiyne carboxylic acid, 2,4-octadecadiin carboxylic acid, 2,4-nonadecadin carboxylic acid Acid, 10,12-tetradecadiyne carboxylic acid, 10,12-pentadecadiyne carboxylic acid, 10,12-hexadecadiin carboxylic acid, 10,12-heptadecadin carboxylic acid, 10,12-octadecadiin carboxylic acid Acid, 10,12-tricosadiyne carboxylic acid, 10,12-pentacosadiyne carboxylic acid, 10,12-hexacosadiyne carboxylic acid, 10,12-heptacosadiyne carboxylic acid, 10,12-octacosadiyne Carboxylic acid, 10,12-nonacosadiyne carboxylic acid, 2,4-hexadiyne dicarboxylic acid, 3,5-octane Di Print carboxylic acid, 4,6-deca-di indicator carboxylic acid, 8,10-like octadecatienyl indicator carboxylic acid.

  Examples of alcohols include ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, dodecyl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, Examples include oleyl alcohol, linoleyl alcohol, ethylene glycol, triethylene glycol, and glycerin.

  Examples of amines include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecyl Amine, hexadecylamine, heptadecylamine, octadecylamine, oleylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, isopropylamine, 1,5 -Dimethylhexylamine, 2-ethylhexylamine, di (2-ethylhexyl) amine, methylenediamine, trimethylamine, triethyl Amine, ethylenediamine, tetramethylethylenediamine, hexamethylenediamine, N, N-dimethylpropan-2-amine, aniline, N, N-diisopropylethylamine, 2,4-hexadiynylamine, 2,4-heptadiynylamine, 2, 4-octadiynylamine, 2,4-decadiynylamine, 2,4-dodecadiynylamine, 2,4-tetradecadiynylamine, 2,4-pentadecadiynylamine, 2,4-hexadecadiynylamine, 2 , 4-octadecadiynylamine, 2,4-nonadecadiynylamine, 10,12-tetradecadiynylamine, 10,12-pentadecadiynylamine, 10,12-hexadecadiynylamine, 10,12-heptadeca Diinylamine, 10,12-octadecadiynylamino , 10,12-tricosadiynylamine, 10,12-pentacosadiynylamine, 10,12-hexacosadiynylamine, 10,12-heptacosadiynylamine, 10,12-octacosadiynylamine, 10,12- Nonacosadiynylamine, 2,4-hexadiynyldiamine, 3,5-octadiynyldiamine, 4,6-decadiynyldiamine, 8,10-octadecadiynyldiamine, stearic acid amide, palmitic acid amide, Examples thereof include lauric acid laurylamide, oleic acid amide, oleic acid diethanolamide, and oleic acid laurylamide.

  When the organic substances listed above or a mixed composition is supplied to the copper oxide layer, the reduction reaction rate with the copper oxide layer is higher than that in the solid state when it is in a liquid state at room temperature. Moreover, storage becomes difficult. Therefore, when it is not used for joining immediately after supply, it is preferable that it is solid at room temperature. Moreover, when these organic substances react with copper oxide, it is preferable that the by-products have a molecular structure that is easily decomposed at a low temperature.

  In the bonding material according to the present invention, the minimum heating temperature required for bonding is 50 ° C., which is very low compared to the solder material. From this, it is possible to introduce polyethylene terephthalate, polyethylene, or the like, which cannot be used from the viewpoint of heat resistance, into the electronic component in the joining using solder. Moreover, if Cu metallization is applied to the electrode outermost surface using vapor deposition or plating technology, Cu metallization is oxidized, and a copper oxide layer is supplied, a copper oxide layer is supplied to metals and other inorganic substances such as organic substances and ceramics. Is possible.

  Electronic members having a copper oxide layer as a bonding material of the present invention on the surface of the electrode or connection terminal using this characteristic include TAB for CSP, COF carrier tape, lead frame, ceramic wiring board, organic wiring board, LSI There is a chip or a semiconductor package.

  The present invention can be applied to an electronic member for flip mounting. In the present invention, as described above, since metal bonding can be obtained with no pressure or low pressure of 0 to 20 MPa, it is possible to reduce the pressure in flip chip mounting and reduce deformation of wiring and the like. be able to.

  In the flip mounting technique, there is a case where a technique of assisting the strength of the entire joint portion by filling a gap between the joined members with a resin in order to reduce the joint area by fine pitch joining. Since the conventional paste-like bonding material has fluidity, there has been a problem that flip chip mounting cannot be performed by previously installing a resin. Therefore, in the case of a structure filled with resin, it is necessary to fill the resin after joining the members. On the other hand, since the bonding material of the present invention is integrated with the electrode, it is possible to perform flip chip mounting in a state where a resin is previously installed. Thereby, the process can be omitted as compared with the conventional method.

  In the flip mounting technology according to the present invention, a method in which a bump is formed as a protrusion type and inserted into a concave electrode, pressed against a planar electrode to destroy an oxide film of a bonding partner electrode, or a resin is previously inserted between bumps Can be taken. In a conventional paste material coating layer, the coating layer peels off due to the shearing force at the time of insertion, and this method cannot be taken. However, in the present invention, it is possible to improve the adhesion with the base by making the copper oxide into a high-density layer. In addition, when the base is made of Cu metallization, the strength between the copper oxide layer and the base is preferably increased. Furthermore, when destroying the oxide film on the bonding partner electrode, the bump surface hardness is increased by making the bump-type bump surface a copper oxide layer, and the surface is pressed lower than when Cu, Au, Ag, Al is used. It is possible to destroy the oxide film of the bonding partner electrode.

  By producing an electronic component using the joining member described above, for example, one or more connection terminals provided on the circuit board as illustrated in FIG. An electronic component having two or more electrode terminals electrically bonded via a bonding layer, wherein the bonding layer is mainly composed of sintered copper having a crystal grain size of 1000 nm or less, and the bonding It is possible to provide an electronic component characterized in that the entire or part of the electrode surface other than the layer is a roughened layer of metallic copper. It has been confirmed that if the crystal grain size is larger than 1000 nm, the sinterability deteriorates and sufficient bonding strength cannot be obtained.

  By being composed mainly of Cu, which has excellent thermal conductivity among metals, it becomes possible to ensure the heat dissipation required as the density increases. Further, since the thickness of the bonding layer can be reduced and the electrical resistivity is low, the signal can be speeded up. Furthermore, since the electrode surface other than the bonding layer is formed as a roughened layer as a part of the electrode surface, it is not necessary to remove a region that becomes a bonding defect when no pressure is applied.

  In the case of a structure in which a resin is filled between the bonding members, it is possible to increase the adhesion strength with the resin by making the electrode surface not corresponding to the bonding region also copper oxide. Thereby, it is possible to improve connection reliability. As described above, the resin can be filled before heating.

  In the filled resin, fillers having different thermal expansion coefficients such as alumina, aluminum nitride, and silicon nitride may be mixed. Thereby, the thermal stress which arises from the difference in the thermal expansion coefficient between Si chip and Cu wiring, for example can be relieved.

  As described above, for example, a thermal stress is generated between the Si chip and the Cu wiring due to the difference in the thermal expansion coefficient of the raw material when the electronic component is manufactured or the temperature of the usage environment increases. On the other hand, by reducing the density of sintered copper, which is a bonding layer, and filling resin inside the sintered copper, absorption of thermal strain can be further improved and stress applied to the Si chip can be reduced. Is possible. The density of sintered copper in the bonding layer can be controlled by reducing the pressure applied during bonding. The resin can be filled either before or after joining as described above.

  By selecting the material of the electrode or connection terminal to be subjected to Cu metallization from simple substance, alloy or mixture of Pt, Ni, Co, Si, Fe, Ti, Mo, Al, etc., the coefficient of thermal expansion, corrosion resistance, etc. It is possible to impart mechanical properties, chemical properties, and the like to the joint.

  Moreover, since the junction part which concerns on this invention is comprised mainly by Cu, the melting | fusing point is much higher compared with a solder material. The current mounting method in the manufacturing process of a semiconductor device is mainly to use a hierarchical solder, and the solder used in the primary mounting is Sn-Ag-Cu solder mainly used in the secondary mounting. It is calculated | required to have melting | fusing point more than mounting temperature (230-260 degreeC). Therefore, conventionally, high-temperature solder (lead content: about 96%, melting point: about 300 ° C.) is often used. Therefore, from the viewpoint of this melting point, the group of Ag, Au, Cu, Pt, Ni, Co, Si, Fe, Ti, Mo, Al, which is a metal whose melting point exceeds 300 ° C. even when the base is alloyed with Ag. It is preferable that it is the simple substance chosen from these, its alloy, or its mixture. This makes it possible to make the high-temperature solder lead-free, which is difficult at present.

  For example, when a package having a semiconductor junction according to the present invention is further mounted on a circuit board, the junction does not melt even if it is joined using a solder material. Moreover, you may use for joining of a semiconductor package and a circuit board. Furthermore, it is also possible to join together.

  As described above, the bonding material according to the present invention has a minimum heating temperature required for bonding of 50 ° C., which is very low compared to the solder material. Therefore, in the case where heat resistance is not a problem, particularly in a joint where stress relaxation is necessary, Sn or Sn alloy, or In or In alloy, which has a stress relaxation capability than sintered copper, can be included in the electrode configuration. That's fine. Stress relaxation is also possible by lowering the elastic modulus by forming a bonded portion made of sintered copper into a porous structure. When strength is not required and heat resistance is required, Sn or Sn alloy, or In or In alloy is melted and reacted with copper particles generated by reduction from the copper oxide layer, resulting in a high melting point. An intermetallic compound may be used. Under the present circumstances, since the copper particle produced | generated from copper oxide has a large surface area, there exists an effect which can shorten the reaction time used as an intermetallic compound.

  By including bumps in the electrode configuration, the distance between the electronic component and the circuit board can be easily controlled. Since the bonding can be performed at a pressure lower than the bonding pressure applied by the pressure bonding of the metal bumps, it is possible to reduce the deformation of the wiring and the like. In addition, since the amount of plastic deformation in the horizontal direction of the bumps is reduced, a finer pitch interval can be achieved.

  If the bump is made of a metal such as Al, Sn, Cu, Au, In, or Ag having a low hardness, a metal such as an alloy, a plastic, a resin, or the like, it is possible to further reduce the pressure applied at the time of joining.

  If bumps are made of bumps such as high hardness Al, Cu, Au, Ag, Ni, metals such as alloys or ceramics, and ceramic bumps, the oxide film of the mating electrode can be destroyed and bonded to achieve metal bonding. This is possible with low pressure. The hardness of the metal can be changed by heat treatment, strain application, and plating solution selection.

  In addition, in the present invention, since the bonding material can be supplied to bumps of various materials and shapes with high accuracy, it is possible to perform bonding with insulation by performing vapor deposition or plating on a part of plastic, resin, ceramic, etc. Become.

  One of the electronic components according to the present invention is an RFID tag. The RFID tag of the present invention has an effect that the thickness of the joint can be reduced as compared with the conventional one. Moreover, in the joining using solder, it is possible to introduce polyethylene terephthalate or polyethylene, which could not be used from the viewpoint of heat resistance, into the electronic component.

  Various shapes can be obtained by processing, casting, or welding the copper metal before being oxidized into copper oxide. In addition, in consideration of pressurizing and joining after joining, annealing is performed after processing to reduce the hardness and facilitate plastic deformation during pressurizing during joining, thereby improving the adhesion of the joining surface and joining strength. Rises.

  In addition to the narrow pitch between electrodes and terminals of electronic components so far, in order to achieve a higher mounting area density, build-up wiring boards with built-in components, chip stacking within the same package, and stacking between packages Such a three-dimensional mounting technique has been proposed. In this technique, in addition to narrowing the pitch, as a countermeasure for increasing the height of signals by increasing the speed of signals and mounting in the vertical direction, it is particularly required to reduce the height of the joint compared to the conventional method.

  Unlike the paste material, the bonding material according to the present invention can suppress the supply of organic matter to the minimum necessary. Therefore, the amount of gas generated during bonding can be reduced. As a result, it is possible to perform bonding with less contamination of surrounding parts by the generated gas. This characteristic is an optimum bonding material for the above-described three-dimensional mounting.

  By applying the present invention, it is a multilayer wiring board in which one or more electronic components are incorporated, and the bonding layer between the electrodes of the electronic component has a crystal grain size of 1000 nm or less. It is possible to provide a multilayer wiring board with built-in electronic components, characterized in that the electrode surface other than the bonding layer and the entire surface or part of the resin are interposed with a roughened layer of metal copper or copper oxide. . Thereby, adhesiveness with resin can be improved with the shortening of a junction part.

  In addition, it is a laminated chip in which a plurality of LSI chips are laminated, and the electrodes between the chips are electrically bonded via a bonding layer, and the bonding layer has a crystal grain size of 1000 nm or less. It is possible to provide a laminated chip which is mainly composed of copper and is characterized in that the entire surface or part of the electrode surface other than the bonding layer is a roughened layer of metallic copper.

  One embodiment of a method for manufacturing an electronic member or electronic component according to the present invention will be described below.

  The present invention provides an electronic member in which a copper layer is formed on the outermost surface of an electrode for inputting / outputting or connecting an electric signal, and further, the copper layer is subjected to oxidation treatment, and all or part of the copper layer is a copper oxide layer. Features a manufacturing method. By forming a copper layer, it is possible to supply copper oxide as a bonding material to conductors, semiconductors, and insulators of various shapes, and bond them at a low temperature, low pressure, or no pressure.

  In the above manufacturing method, the copper layer is formed by forging or welding.

  In the above manufacturing method, the copper layer is formed by vapor deposition or plating.

In the above manufacturing method, the copper oxide layer is formed by anodization or ozone oxidation.
In the above manufacturing method, the copper oxide layer is formed by heat treatment.

  If an anodic oxidation method is applied as a technique for changing the copper layer to a copper oxide layer, the curvature and layer thickness of the surface of the copper oxide layer can be controlled with high accuracy. In the case of the electroless anodic oxidation method, the target copper oxide layer can be produced by changing the solution to be produced and the temperature. In the case of the electrolytic anodic oxidation method, the target copper oxide layer can be produced by changing the solution to be produced, the current density, the potential, and the temperature. The solution may be made of an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide.

When the treatment in the liquid is difficult, a technique of converting the copper layer to a copper oxide layer with ozone gas can be taken. It is possible to control the curvature and layer thickness of the copper oxide layer with high accuracy also by ozone oxidation.
That is, the target copper oxide layer can be produced by changing the production temperature and ozone concentration.

  In the case of copper, it is possible to produce a copper oxide layer by heating and oxidation in air or in an oxidizing atmosphere.

  The present invention is a mounting method of an electronic component, wherein one or more connection terminals provided on a circuit board and one or more electrode terminals provided on an electronic member are electrically bonded via a bonding layer, At least one surface of the connection terminal or the electrode terminal is composed of a copper oxide layer, a reducing agent is supplied to the copper oxide layer, heating at 50 ° C. to 400 ° C. is applied to at least the bonding surface, and at least oxidation is performed. A feature is a mounting method of an electronic component that electrically joins between the connection terminal and the electrode terminal by applying a pressure of 0 to 100 MPa to the joint surface when copper is reduced to metallic copper.

  As an electrode that can be bonded to the bonding member (copper oxide layer) according to the present invention, if the metallized layer on the outermost surface of the electronic component is a simple substance or alloy of Au, Ag, Pt, Pd, Cu, Ni, a reducing agent is used. Metal bonding is possible by selecting. Further, it is possible to bond to a metal having a stable oxide film such as Al through the oxide film. Moreover, joining of copper oxide layers is also possible.

  By supplying the reducing agent only to the bonding surface of the electronic member, the portion other than the bonding surface can remain as the copper oxide layer. This is a technique to leave the area where the reducing agent is not applied as copper oxide when joining in an inert atmosphere such as nitrogen or argon atmosphere, or in a reducing atmosphere such as air or vacuum. It is possible to introduce an electric circuit using a large difference in values.

As a technique for reducing copper oxide, gas may be used in addition to using a reducing agent. That is, by applying heating at 50 ° C. to 400 ° C. at least to the bonding surface in a reducing gas atmosphere, and applying pressure of 0 to 100 MPa to the bonding surface when at least copper oxide is reduced to metallic copper, The space can be electrically joined. The reducing atmosphere gas may be an atmosphere having a reducing effect on copper oxide, such as hydrogen, formic acid, acetic acid, and ethanol. In addition, an effect of reducing or preventing oxidation of the oxide film existing on the outermost surface of the electrode of the electronic component can be expected.
In particular, by reducing in a hydrogen atmosphere, the only gas generated is water, and the surrounding contamination is significantly reduced.

It is also possible to reduce copper oxide using a reducing agent and a reducing atmosphere (gas) in combination.
Depending on the type of the reducing agent, the effect of electroless plating in which the reduced copper particles are dispersed in the reducing agent in a liquid state and deposited on the electrode is exhibited. Since this effect does not depend on the magnitude of the applied pressure, it is preferable to introduce a liquid phase even in a hydrogen atmosphere when joining at a low pressure.

  Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the embodiments described here, and may be combined as appropriate.

  In this embodiment, a component built-in type multilayer wiring board according to the present invention will be described. 2A to 2C are schematic cross-sectional views of components incorporated in a component built-in type multilayer wiring board. FIG. 2A is a schematic cross-sectional view of a passive component 803 such as an inductor, a capacitor, and a resistance component, in which a metallized layer 802 is formed on an electrode, and a copper oxide layer 801 is formed on the surface thereof. The metallized layer and the copper oxide layer can be produced by barrel plating.

  FIG. 2B is a schematic cross-sectional view of the LSI chip 804. A bump 805 provided on the electrode has a protruding shape, and a copper oxide layer 806 is further formed. FIG. 2C shows a schematic cross-sectional view between a partial core layer and an interlayer of a multilayer wiring board. Conduction in the height direction of the core 807 is performed by the wiring 809 on the surface of the through hole 808. Conduction of the prepreg 810 between the layers is performed by a bump-shaped through electrode 812 having a copper oxide layer 811 on the surface. Further, the copper oxide layer 811 may be provided on the surface of the wiring 809 (an interface between the prepreg 810 and the wiring 809).

  FIG. 3 is a schematic cross-sectional view of a component built-in type multilayer wiring board manufactured using the above components. The passive component 803, the LSI chip 804, and the through electrode 812 are joined by copper particles produced by reduction of copper oxide by the method described above, and are mounted on the electrode via the sintered copper layer 813. Moreover, since the copper oxide layers other than the respective joint portions become the sintered copper roughened layer 814, the degree of adhesion with the prepreg 810 can be improved. In addition, by providing a hard copper oxide on the bump surface such as the bump 805 and the through electrode 812, it is possible to break the oxide film to be bonded with low pressure.

  FIG. 4 shows a structure in which electrodes are provided on both surfaces of an electronic component 803 and upper and lower wirings and electrodes are connected in the stacking direction of the multilayer wiring board. FIG. 5 shows a structure in which electrodes are provided on both surfaces of an electronic component, and the wiring and electrodes on the side surfaces of two wiring boards arranged in the same layer are connected. As shown in FIGS. 4 and 5, the electronic component is connected in a direction perpendicular to the stacking direction of the multilayer wiring board or in a direction parallel to the stacking direction of the multilayer wiring board. The degree of freedom of design is high because the thickness of the laminated substrate can be minimized and heat dissipation can be taken into consideration.

  In three-dimensional mounting, control in the height direction is important. In the bonding mode according to the present invention, there are effects that the height of the bonding layer can be reduced, there is no inclination, and less gas is generated during bonding. In addition, since each bonding layer is thin, there is an effect that a circuit with little delay of an electric signal can be obtained.

  In this example, a multilayer chip according to the present invention will be described. FIG. 6 is a schematic cross-sectional view of a multilayer chip. A through electrode 903 is formed in the semiconductor element 901 with an insulating layer 902 interposed therebetween. Further, Cu metallization 904 is provided on one side when the through electrode is formed, and a copper oxide layer is further formed. Using this copper oxide layer, a plurality of semiconductor elements are stacked via a bonding layer 905 mainly composed of sintered copper.

  On the other hand, the semiconductor element 906 having Cu metallization formed on both sides is prepared by first performing Ni plating and then Cu plating when the through electrode is not Cu, for example, Al, and then dicing the semiconductor element. Yes. By doing so, a part of the Cu metallized 907 can be anodized and the electrode 909 of the interposer 908 can be joined.

  It is also possible to apply Cu metallization to only one side and join the interposer by brazing or crimping. Furthermore, regarding the bonding between the bump 910 provided on the interposer and the circuit board, the present invention may be used or other bonding methods may be used.

101 Copper oxide 102 Metal copper 103 Copper oxide outer shape 801, 806, 811 Copper oxide layer 802 Metallized layer 803 Passive component 804 LSI chip 805, 910 Bump 807 Core 808 Through hole 809 Wiring 810 Prepreg 812, 903 Through electrode 813 Baked Copper layer 814 Sintered copper roughened layer 901, 906 Semiconductor element 902 Insulating layer 905 Bonding layer 904, 907 Cu metallized 908 Interposer 909 Electrode

Claims (25)

  An electronic member comprising an electrode for inputting / outputting an electric signal or a connection terminal for connecting an electric signal, wherein an outermost surface of the electrode or the connection terminal is a copper oxide layer.   The electronic member according to claim 1, wherein a base of the copper oxide layer is a copper layer.   The electronic member according to claim 1, wherein the copper oxide layer has a thickness of 100 nm to 10 μm.   The electronic member according to claim 1, wherein an outermost surface of the copper oxide layer has a curvature radius smaller than 1 μm.   2. The electronic member according to claim 1, wherein a layer made of alcohols, carboxylic acids and amines which are solid at room temperature is formed on the surface of the copper oxide layer.   The electronic member according to claim 1, wherein the copper oxide layer is provided on a connection terminal or an electrode having a curvature.   2. The electronic member according to claim 1, wherein the copper oxide layer has a connection terminal or an electrode having a protruding shape.   An electronic component in which one or more electrode terminals provided on an electronic member are electrically bonded via a bonding layer to one or more connection terminals provided on a circuit board, the bonding layer comprising: It is composed mainly of sintered copper having a crystal grain size of 1000 nm or less, and the entire or part of the electrode surface not in contact with the bonding layer is a roughened layer of metal copper or copper oxide. Electronic parts.   9. The resin according to claim 8, wherein a resin is filled between the circuit board and the electronic member, and the entire surface or a part of the electrode not in contact with the bonding layer is interposed through a roughened layer of metal copper or copper oxide. An electronic component characterized by being adhered to.   9. The electronic component according to claim 8, wherein the sintered copper is porous, and a resin is filled in the pores of the sintered copper.   9. The connection terminal or the electrode according to claim 8, wherein the connection terminal or the electrode is made of at least one material selected from a simple substance, an alloy, or a mixture of Ag, Au, Cu, Pt, Ni, Co, Ti, Mo, Fe, Al, and Zn. Electronic parts characterized by being made.   9. The electronic component according to claim 8, wherein the connection terminal or the electrode is made of at least one material selected from a simple substance of Sn, an Sn alloy, or a mixture.   The electronic component according to claim 9, wherein bumps are present at a joint portion between the electrode and the joint terminal.   A multilayer wiring board having at least one electronic component built therein, wherein a bonding layer between electrodes of the electronic component is made of sintered copper and resin having a crystal grain size of 1000 nm or less, and the bonding A multilayer wiring board with a built-in electronic component, characterized in that a layer, an electrode surface, and the entire surface or a part of a resin are provided with a roughened layer of metallic copper or copper oxide.   A plurality of LSI chips are laminated chips, and the electrodes between the chips are electrically bonded via a bonding layer, and the bonding layer is made of sintered copper having a crystal grain size of 1000 nm or less. A multi-layered chip characterized in that the whole or part of the electrode surface other than the bonding layer is a roughened layer of metallic copper.   In the method of manufacturing an electronic member having an electrode for inputting / outputting an electric signal or a connection terminal for connecting an electric signal, a copper layer is formed on the outermost surface of the electrode or the connection terminal, and the copper layer is further oxidized. A method for producing an electronic member, wherein all or part of the copper layer is a copper oxide layer.   The method of manufacturing an electronic member according to claim 16, wherein the or the copper layer is formed by forging or welding.   The method of manufacturing an electronic member according to claim 16, wherein the copper layer is formed by vapor deposition or plating.   The method of manufacturing an electronic member according to claim 16, wherein the copper oxide layer is formed by anodization or ozone oxidation. The method of manufacturing an electronic member according to claim 16, wherein the copper oxide layer is formed by heat treatment.   An electronic component mounting method for electrically bonding one or more connection terminals provided on a circuit board and one or more electrode terminals provided on an electronic member via a bonding layer, wherein the connection terminals or At least one surface of the electrode terminal is composed of a copper oxide layer, a reducing agent is supplied to the copper oxide layer, heating at 50 ° C. to 400 ° C. is applied to at least the bonding surface, and the copper oxide is converted into metallic copper. A method for mounting an electronic component, wherein the connecting terminal and the electrode terminal are electrically joined by applying no pressure or a pressure greater than 0 and a pressure of 100 MPa or less to the joint surface when reducing.   23. The electronic component mounting method according to claim 22, wherein the reducing agent is an alcohol, a carboxylic acid, or an amine.   23. The electronic component mounting method according to claim 22, wherein the reducing agent is supplied only to a bonding surface of the electronic member, and the copper oxide layer remains other than the bonding surface.   An electronic component mounting method for electrically bonding one or more connection terminals provided on a circuit board and one or more electrode terminals provided on an electronic member via a bonding layer, wherein the connection terminals or At least one surface of the electrode terminal is composed of a copper oxide layer, and heating at 50 ° C. to 400 ° C. is applied to at least the bonding surface in a reducing gas atmosphere, and at least when copper oxide is reduced to metallic copper, no addition is applied. A method for mounting an electronic component, wherein the connection terminal and the electrode terminal are electrically joined by applying a pressure or a pressure of 0 to 20 MPa to the joint surface.   25. The electronic component mounting method according to claim 24, wherein the reducing agent is supplied to the copper oxide layer and heat-treated.

Images