KR101088631B1 - A via paste composition - Google Patents

Abstract

The present invention relates to a conductive via paste composition, wherein the via paste composition according to the present invention comprises a conductive material and a thermosetting resin, wherein the conductive material is a silver (Ag) powder having a single or more particle distribution, silver (Ag) coated copper (Cu) powder, and a silver nanoparticle dispersion solution, wherein the thermosetting resin comprises an epoxy resin.

Via, Paste, Silver, DMF, Curing, Low Temperature, Hybrid

Description

Via paste composition {A VIA PASTE COMPOSITION}

The present invention relates to a conductive paste composition for forming a conductive connection between conductive members. In particular, the present invention relates to conductive via paste compositions used for interlayer connection of sintered ceramic hybrid substrates.

As a substrate for modules on which elements such as resonators, capacitors, coils, filters, etc. are formed, or a substrate on which semiconductor elements, chip capacitors, chip resistors, etc. are mounted, a circuit board manufactured by sintering an inorganic insulating material such as ceramics or glass-ceramic It is used.

In general, the circuit board is electrically connected through the via conductor filled in the via hole of the substrate between the wiring conductors formed on the lower surface and the wiring conductors located on the upper and lower surfaces.

As the width of the wiring conductor becomes narrow in the range of several tens to several hundreds of micrometers with such a high density of electronic devices, the diameter of the via hole is also reduced to about 50 to 300 micrometers.

Usually, the circuit board as mentioned above is manufactured by the following method.

For example, when the circuit board is made of glass-ceramic, first, a suitable organic binder, a solvent, a plasticizer, and the like are further added to a raw material powder made of glass powder and ceramics powder such as silicon oxide and aluminum oxide, and, if necessary, mixed. Make a slurry.

This slurry is formed using a doctor blade method or the like to form a green sheet having a thickness of about 25 to 300 µm. This green sheet is cut | disconnected by the dimension larger than the dimension of the circuit board as a finished product, considering that each dimension of the green sheet shrink | contracts about several to several ten% at the time of baking mentioned later.

After that, a via hole having a diameter of about 50 to 300 µm is drilled at a predetermined position of the green sheet by using a laser method or a punching method.

The via hole is filled with a conductive paste for forming via conductors made of metal powders such as copper, silver, and nickel, a solvent, an organic binder, and the like, using a conventionally known screen printing method, and drying the conductive paste for forming via conductors. .

On the surface or bottom surface of the green sheet, a screen printing method is used to contact the conductive paste for via conductor formation filled in the via hole as described above, and is completed from metal powders such as copper, silver and nickel, solvents and organic binders. The conductive paste for pattern formation is printed by a wiring pattern, and then the conductive paste for pattern formation is dried.

A green sheet laminated with a conductive sheet for via conductor formation and a green sheet printed with a conductive paste for pattern formation, laminated so that the via paste forming conductive paste and the pattern forming conductive paste are in contact with each other. By baking at a high temperature for several tens of minutes to several hours at a temperature of about 700 to 1600 ° C, a single-layer circuit board or a circuit board formed by laminating a plurality of green sheets can be obtained.

Recently, however, research has been conducted to form a substrate by curing rather than firing an electromagnetic plate having such a firing concept. This has the beneficial effect of lowering the heat treatment temperature up to 500 ° C. or less.

Typically, via pastes are manufactured to enable sintering of conductive powders at temperatures of 700 ° C. or more using conductive fillers and glass frits for simultaneous firing of glass-ceramic based circuit board materials, via pastes, and printed circuits.

The binder resin has a property of being removed by heat treatment. When the paste is applied to a hybrid low temperature process in which a substrate is formed by curing at a lower temperature, the conductive resin is not only retained but also the conductive raw powder is not connected well. There is a problem that the resistance value of the paste material is very bad.

The present invention is to solve the problems as described above, to cope with a sintered ceramic-polymer hybrid substrate produced in a hybrid form, in particular a via paste composition for interlayer connection of a sintered ceramic hybrid substrate having a low heat treatment temperature The purpose is to provide. Specifically, the present invention provides a via paste composition for producing a via paste for a sintered ceramic hybrid substrate, in particular having a curing temperature range of 200 to 300 ° C., a shrinkage of which is not large, and strong against external thermal shock. For the purpose of

The present invention has been made in order to achieve the above object, the first aspect of the present invention relates to a via paste composition consisting of a conductive material and a thermosetting resin, the conductive material, the silver having a single or more particle distribution ( Ag) powder, silver (Ag) coated copper (Cu) powder, and silver nanoparticle dispersion solution, wherein the thermosetting resin comprises an epoxy resin.

The silver powder is a silver powder having an average particle diameter in a range of 100 to 300 nm, and the silver coated copper powder is a coated copper powder having an average particle diameter in a range of 1 to 10 μm, and the silver nanoparticle dispersion solution is a primary It is preferable that it is a silver particle dispersion solution whose silver particle size is 10 nm or less.

The epoxy resin includes either phenol novolac epoxy or cresol novolac epoxy. In addition, content of the said conductive material is 70 to 95 weight% of the total weight of the said via paste composition.

The via paste composition further comprises a coupling agent for improving the compatibility of the epoxy resin with the silver powder and the silver coated copper powder, wherein the coupling agent is a silane or titanate coupling agent.

Silver nanoparticle dispersion solution includes a solvent capable of dissolving the epoxy resin, the solvent is dimethylformamide (DMF), ethyl carbitol acetate, butyl carbitol acetate, and gamma buty It may be selected from the rockactone (gamma butyrolactone).

Silver content of the said silver nanoparticle dispersion solution is 5-30 weight% of the total weight of the said silver nanodispersion solution.

In addition, the via paste composition may further include a curing agent and a curing aid for curing the epoxy resin, and the curing agent and curing aid include a curing aid such as phenols or acid anhydrides curing agents, imidazoles, tertiary amines and the like. .

In addition, a second aspect of the present invention relates to a method for producing a via paste composition, comprising: preparing a silver nanoparticle dispersion solution having a primary particle size of less than 10 nm and comprising a solvent of a thermosetting resin; Dissolving a thermosetting resin in the silver nanoparticle dispersion solution; Injecting and mixing nano-sized silver powder having a mean particle size of 100 to 300 nm into a solution in which the thermosetting resin is dissolved; Heating and drying the mixture until the solvent in the mixture has evaporated; Constitutive features include the step of adding and mixing the micro-size silver coated copper powder with an average particle diameter of 1 to 10 μm to the mixture after the solvent is dried.

The thermosetting resin is an epoxy resin, and dissolving the thermosetting resin in the silver nanoparticle dispersion solution further adds a curing agent to dissolve the thermosetting resin.

It is preferable that the said epoxy resin is a liquid phenol novolak epoxy, and the said hardening | curing agent is a liquid acid anhydride.

In addition, the solvent of the thermosetting resin is DMF (dimethylformamide), and the step of heating and drying the mixture is heated and dried on a hot plate until the DMF evaporates.

In the step of adding and mixing the micro-size silver coated copper powder, a paste solvent is further added and mixed.

According to the characteristic configuration of the present invention described above, it is possible to provide a via paste for interlayer connection that is excellent in electrical conductivity and excellent in solder shock resistance after via filling in response to a low temperature process of a sintered ceramic hybrid substrate.

Hereinafter, embodiments of the present invention will be described. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to those skilled in the art to more fully describe the present invention, and the present invention is not limited to these examples.

First, the conductive paste composition used for forming the via hole conductor according to the present invention contains a conductive material and a thermosetting resin.

Preferably, the conductive material is made of a metal powder, and gold (Au), silver (Ag), palladium (Pd), copper (Cu), nickel (Ni), etc. may be employed in consideration of electrical conductivity. Alloys are also possible. In this case, the metal that can be most preferably employed is silver (Ag) in consideration of excellent electrical properties and adhesive properties.

Specifically, the conductive material used in the conductive via paste composition according to the present invention includes silver (Ag) powder and silver (Ag) coated copper (Cu) powder having a single or more particle distribution, and a silver nanoparticle dispersion solution. It includes.

Silver powder and silver coated copper powder include micro size silver coated copper powder with an average particle diameter in the range of 1-10 micrometers, respectively, and nano size silver powder with an average particle diameter in the range of 100-300 nm.

The silver nanoparticle dispersion solution uses a silver nanoparticle dispersion solution having a primary silver particle size of 10 nm or less, which requires a silver particle size of 10 nm or less to obtain low temperature sintering effect of silver particles even at a low heat treatment temperature of 300 degrees or less. This is because the conductivity of the paste can be increased, and the bonding force with the copper foil can be enhanced when the via filling structure is formed.

In addition, the conductive paste composition of the present invention includes a thermosetting resin together with the conductive material. The thermosetting resin may include a liquid epoxy resin, and the conductive paste composition may further include a liquid curing agent.

It is preferable that the total content of the micro & nano size silver or silver coated copper powder used for this invention, and silver nanoparticles is 70 to 95 weight% in the final electroconductive paste containing a solvent.

If the total content of the micro or nano-sized silver or silver coated copper powder and the silver nanoparticles is less than 70 wt%, the electrical conductivity is not good, and if the total content is more than 95 wt%, it is difficult to manufacture the conductive paste. There is a disadvantage that the print workability is worse.

The shape of the silver or silver coated copper powder may be used in the form of flakes or spherical. In order to improve the compatibility with the resin, the silver or silver coated copper powder is preferably treated with a coupling agent, for example, a silane or titanate coupling agent may be used. Moreover, you may use a dispersing agent in order to improve dispersibility.

In addition, the silver nanoparticle dispersion solution having a size of 10 nm or less of the primary silver particles used in the present invention should be capable of dissolving an epoxy resin and a curing agent for the final paste, and at the same time, should be capable of effective dispersion of silver nanoparticles. do.

As a suitable solvent, it is preferable to use a polar solvent such as DMF (dimethylformamide), ethyl carbitol acetate, butyl carbitol acetate, gamma butyrolactone, and the like.

The content of silver particles in the silver nanoparticle dispersion solution is preferably in the range of 5 to 30% by weight, more preferably 10 to 15% by weight. If the content of silver nanoparticles in the silver nanoparticle dispersion solution is less than 5%, too much solution is consumed to make the paste and it is not economical.If the content of silver nanoparticles in the silver nanoparticle dispersion solution exceeds 30% of the total weight, the silver particles Not only does it have difficulty in effective dispersal, but it is also poor in long-term preservation.

As a thermosetting resin, it is preferable to use the epoxy resin which is excellent in heat resistance and joining property, and it can use a solid state or liquid state at normal temperature. In particular, in order to minimize dry shrinkage, it is more preferable that it is a liquid thermosetting resin rather than a solid thermosetting resin.

Moreover, it is preferable to select and use either a phenol novolak epoxy or cresol novolak epoxy which is excellent in heat resistance among an epoxy resin. It is preferable to use a phenol or acid anhydride curing agent, and a curing aid such as imidazoles and tertiary amines together as a curing agent and a curing aid used to cure the epoxy resin.

First, the manufacturing method of the electrically conductive paste which concerns on Example 1 is demonstrated.

Example 1

  -Micro size silver coated copper powder: AgCuS7 with 7μm average particle diameter (provided by NCPC)

  -Nano size silver powder: NP-S150 with 150nm average particle diameter (provided by NTBase)

  -Epoxy resin: Liquid phenol novolac epoxy (YDPN-631, provided by Kukdo Chemical)

  -Curing agent: Liquid acid anhydride (HN-2200, provided by Kukdo Chemical)

  Curing aid: BDMA (benzyldimethylamine) (Sigma-Aldrich reagent)

  Additives: coupling agents, dispersants

  -Silver nanoparticle dispersion solution: Ag 10wt% in DMF (primary particle size 10nm or less)

  -Solvent for paste: α-terpineol

The manufacturing method of the conductive paste which concerns on the 1st Example which consists of the said composition is as follows.

First, 2.4 g of liquid phenol novolac epoxy YDPN-631 and 2.1 g of liquid acid anhydride HN-2200 as a curing agent were added and dissolved in 20 g of silver nanoparticle dispersion solution.

Then, after adding each additive, 12 g of NP-S150 powder, which is a nano-sized silver powder having a 150 nm average particle diameter, was added thereto, followed by high speed mixing.

The mixture was placed on a hot plate and heated to dryness until all of the DMF was evaporated. At this time, excessive heat is applied to maintain the proper temperature so that the paste does not cure.

To the mixture remaining after the DMF was evaporated, 28 g of AgCuS7 powder having a 7 μm average particle diameter as a micro size silver coated copper powder was added, 1.5 g of terpinol was added for viscosity control, followed by high speed mixing, and then 3 rolls. Paste was made using wheat. The conductivity of the paste cured for 1 hour at 200 ° C, 250 ° C, and 300 ° C was respectively evaluated.

  -Curing condition for conductivity evaluation: 200 ℃, 250 ℃, or 300 ℃, 1 hour

  -Conductivity measurement: Measured using Mitsubishi Chemical's Loresta-GP (Loresta-GP).

Table 1 shows the volume resistance and the electrical conductivity for each curing temperature of the via paste composition prepared according to the first embodiment.

(Table 1) Volume resistance and electrical conductivity by curing temperature

As can be seen in Table 1, it can be seen that the paste prepared according to the present invention at each curing temperature has good volume resistance and electrical conductivity.

Example 2

First, the manufacturing method of the electrically conductive paste which concerns on Example 2 is demonstrated.

  -Micro size silver coated copper powder: AgCuS7 with 7μm average particle diameter (provided by NCPC)

  -Nano size silver powder: NP-S150 with 150nm average particle diameter (provided by NTBase)

  -Epoxy resin: Liquid phenol novolac epoxy (YDPN-631, provided by Kukdo Chemical)

  -Curing agent: Liquid acid anhydride (HN-2200, provided by Kukdo Chemical)

  Curing aid: BDMA (benzyldimethylamine) (Sigma-Aldrich reagent)

  Additives: coupling agents, dispersants

  -Silver nanoparticle dispersion solution: Ag 10wt% in DMF (primary particle size 10nm or less)

  -Solvent for paste: α-terpineol

A method of manufacturing a conductive paste according to a second embodiment of the composition is as follows.

First, 30 g of silver nanoparticle dispersion solution was mixed with 12 g of NP-S150 powder having a 150 nm average particle diameter as a nano-size silver powder, and 2.4 g of YDPN-631 which is a liquid phenol novolak epoxy as an epoxy resin. Evaporate.

After the DMF was evaporated, 2.1 g of liquid acid anhydride, HN-2200, a curing aid, and an additive were added to the remaining mixture as a curing agent. Then, 28 g of copper powder coated with micro-sized silver was added. After adding 2 g of terpinol, the mixture was mixed at high speed, and then pasteurized using a 3 roll mill.

The via paste composition according to Example 2 is to improve the final curing characteristics of the paste. Thereafter, the conductivity of the paste cured for 1 hour at 200 ° C, 250 ° C, and 300 ° C was evaluated.

Table 2 shows the volume resistivity and the electrical conductivity according to the curing temperature of the via paste composition prepared according to the second embodiment.

(Table 2) Volume resistance and electrical conductivity by curing temperature

As can be seen in Table 2, the paste prepared according to the present invention at each curing temperature can be seen that the volume resistance and the electrical conductivity is good.

Table 3 is a table evaluating the bonding force between the via paste and the copper foil in the via formation structure by performing a solder shock test in a 288 ° C lead bath.

In Table 3, Comparative Example 1 is a solder shock test result of a bimodal paste prepared without the silver nano solution.

Table 3 Via Conductivity after Via Fill and Solder Shock Test (Unit: ohm)

As can be seen from Table 3, it can be seen that the pastes (Examples 1 and 2) to which the silver nano solution is added maintain the short state after the solder shock test, and the bonding force between the via paste and the copper foil is maintained. It can be seen that this is excellent.

On the other hand, the bimodal paste prepared without the silver nano solution is opened after the solder shock test, and thus the bonding strength of the via paste and the copper foil is inferior to those of Examples 1 and 2 of the present invention. .

As described above, according to the present invention, it is possible to manufacture a via paste for interlayer connection that is excellent in electrical conductivity and excellent in solder shock resistance after via filling in response to a low temperature process of a sintered ceramic hybrid substrate.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims (14)

As a via paste composition which consists of a conductive material and a thermosetting resin, The conductive material comprises silver (Ag) powder, silver (Ag) coated copper (Cu) powder, and silver nanoparticle dispersion solution having a single or more particle distribution, The thermosetting resin includes an epoxy resin, The via paste composition is, Further comprising a coupling agent for improving the compatibility of the epoxy resin with the silver powder and the silver coated copper powder, The coupling agent is a via paste composition, characterized in that the silane or titanate coupling agent. The method of claim 1, The silver powder is a silver powder having an average particle diameter in the range of 100 to 300 nm, The silver coated copper powder is a coated copper powder having an average particle diameter in the range of 1 to 10 μm, The silver nanoparticle dispersion solution is a via paste composition, characterized in that the primary silver particle size is 10nm or less silver nanoparticle dispersion solution. 3. The method of claim 2, The epoxy resin is via paste composition comprising any one of phenol novolac epoxy or cresol novolac epoxy. The method of claim 3, The content of the conductive material is a via paste composition, characterized in that 70 to 95% by weight of the total weight of the via paste composition. delete The method of claim 1, The silver nanoparticle dispersion solution is via paste composition, characterized in that it comprises a solvent capable of dissolving the epoxy resin. The method of claim 6, The solvent is via paste composition, characterized in that selected from dimethylformamide (DMF), ethyl carbitol acetate, butyl carbitol acetate, and gamma butyrolactone. The method of claim 6, The silver paste of the silver nanoparticle dispersion solution is via paste composition, characterized in that 5 to 30% by weight of the total weight of the silver nanoparticle dispersion solution. The method of claim 8, Further comprising a curing agent and a curing aid for curing the epoxy resin, A via paste composition comprising a curing aid such as a phenol or an acid anhydride curing agent, an imidazole, and a tertiary amine as the curing agent and curing aid. As a method for producing a via paste composition, Preparing a silver nanoparticle dispersion solution having a primary particle size smaller than 10 nm and comprising a solvent of a thermosetting resin; Dissolving a thermosetting resin in the silver nanoparticle dispersion solution; Adding a nano-size silver powder having an average particle diameter of 100 to 300 nm to a solution in which the thermosetting resin is dissolved to form a mixture; Heating and drying the mixture until the solvent of the thermosetting resin is evaporated; Incorporating and mixing the micro-size silver coated copper powder with the average particle diameter of 1 to 10 탆 into the mixture after the solvent is dried, The solvent of the thermosetting resin is DMF (dimethylformamide), Heating and drying the mixture comprises heating and drying the mixture on a hot plate until the DMF evaporates. The method of claim 10, The thermosetting resin is an epoxy resin, Dissolving the thermosetting resin in the silver nanoparticle dispersion solution, the method of producing a via paste composition, characterized in that to further dissolve the thermosetting resin by adding a curing agent. The method of claim 11, The said epoxy resin is a liquid phenol novolak epoxy, and the said hardening | curing agent is a liquid acid anhydride, The manufacturing method of the via paste composition characterized by the above-mentioned. delete The method of claim 10, The micro-size silver-coated copper powder is added and mixed, the method of producing a via paste composition, characterized in that the addition of the paste solvent to further mix.