JP2015062871A - Solid particle dispersion and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase dispersibility of solid particles without the surface modification of the solid particles.SOLUTION: A solid particle dispersion according to an embodiment comprises a dispersion medium, a solid particle in which acid points and basic points coexist on the surface, a first dispersant having only one of an acidic adsorptive group or a basic adsorptive group, and a second dispersant having both of an acidic adsorptive group and a basic adsorptive group.

Description

  The present invention relates to a solid fine particle dispersion and a device.

  By dispersing solid fine particles such as single metal particles such as nickel (Ni) and platinum (Pt) and metal oxide particles in a solvent, wiring and electrodes can be formed on a substrate by inkjet printing or the like. Conductive inks have been proposed (see, for example, Patent Documents 1 and 2). This type of conductive ink is required to stably disperse solid fine particles in a solvent in order to ensure desired conductivity for a conductor to be printed.

  Therefore, the conventional conductive ink is subjected to surface modification of the solid fine particles, for example, so as to obtain solid fine particles whose surface properties are unified at either the acid point or the base point, and further, the acid point or the base point. The dispersibility of the solid fine particles is improved by adding a dispersant having an adsorbing group corresponding to one of the points.

Special table 2008-513565 gazette JP 2012-216425 A

By the way, in the case of solid fine particles in which acid points and base points are mixed on the surface, when a dispersant having an adsorbing group corresponding to one of acid points or base points is added to the solvent, the dispersant is not adsorbed on the particle surface. There will be an area. At this time, the solid fine particles may not be sufficiently dispersed by the dispersant and may aggregate.
When exemplified using a dispersing agent having an acidic adsorbing group that adsorbs to a base point, the dispersing agent selectively adsorbs to the base point on the surface of the solid fine particles, but usually does not adsorb to the acid point. At this time, since there is a region where the dispersant is not adsorbed on the particle surface, an intermolecular force between the solid particles acts in the region, and as a result, the solid fine particles may aggregate.

  The present invention has been made in order to solve the above-described problem, and a solid that can improve the dispersibility of solid fine particles without modifying the surface of the solid fine particles in which acid points and base points are mixed on the surface. An object is to provide a fine particle dispersion and a device.

  The solid fine particle dispersion which is one embodiment of the present invention is a first dispersion having a dispersion medium, solid fine particles in which acid points and base points are mixed on the surface, and either one of an acidic adsorption group or a basic adsorption group. And a second dispersant having both the acidic adsorbing group and the basic adsorbing group.

  In the solid fine particle dispersion, the adsorbable second dispersant is adsorbed on the surface of the solid fine particle with respect to each of the acid point and base point on the surface of the solid fine particle. When exemplified using the first dispersant having an acidic adsorbing group that adsorbs to the base point, the first dispersant selectively adsorbs to the base point on the surface of the solid fine particles, and the second dispersion adsorbs to the acid point. The first dispersant can also adsorb to the basic adsorbing group of the agent. In other words, even in the region where the first dispersant is not adsorbed, the second dispersant is interposed so that it can be adsorbed. As a result, the first dispersant can be adsorbed as a whole on the surface of the solid fine particles, and the solid fine particles can be dispersed by effectively functioning the dispersing action due to the steric hindrance of the first dispersant. Dispersibility can also be improved by reducing the intermolecular force between the solid fine particles as the area where the dispersant on the particle surface is not adsorbed by the second dispersant decreases. Therefore, according to the solid fine particle dispersion, the dispersibility of the solid fine particles in the dispersion medium can be improved without separately performing surface modification of the solid fine particles.

  Here, the solid fine particles included in the solid fine particle dispersion are composed of one or more kinds of particles selected from simple metal particles, metal alloy particles, and ceramic particles. The solid fine particles are composed of simple metal particles and / or non-complex compound particles. In other words, the solid fine particles applied in the present invention do not contain complex compound particles used for pigment inks and the like.

  Such solid fine particle dispersions include those in various states such as slurry (suspension), liquid, and paste. For example, the solid fine particle dispersion can be applied as an inkjet ink.

  Further, since the first dispersant has a molecular weight larger than that of the second dispersant, it is possible to impart a dispersing action due to steric hindrance to the solid fine particles.

  Furthermore, a device which is one embodiment of the present invention is characterized in that a solid fine particle sintered film formed in a pattern using the solid fine particle dispersion described above is provided on a substrate. According to this device, for example, when the solid fine particles have conductivity and the solid fine particle sintered film is configured as a conductor pattern, the dispersibility of the solid fine particles is high as described above. Performance can be obtained, thereby improving electrical connection reliability.

  ADVANTAGE OF THE INVENTION According to this invention, the solid fine particle dispersion and device which can improve the dispersibility of a solid fine particle, without performing the surface modification of a solid fine particle, etc. can be provided.

The figure which shows typically the structure of the solid fine particle dispersion which concerns on embodiment of this invention. The figure which shows the structure of the solid fine particle dispersion of the comparative example 1 typically. The figure which shows the structure of the solid fine particle dispersion of the comparative example 2 typically. The figure which shows typically the structure of the other solid fine particle dispersion different from the comparative examples 1 and 2. FIG. Sectional drawing which shows the device which concerns on embodiment of this invention. The figure which shows the method of the sedimentation test for evaluating the dispersibility of a solid microparticle. The figure which shows the result of the sedimentation test by the method of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the solid fine particle dispersion 10 according to the present embodiment mainly contains a dispersion medium, solid fine particles 7, a first dispersant 3, a second dispersant 5, a binder, and the like. The dispersion medium may be an aqueous dispersion medium or a non-aqueous dispersion medium, and examples thereof include an organic solvent (organic solvent). Examples of the binder include, for example, a polymer solid powder material that dissolves in the dispersion medium.

The solid fine particles 7 are particles that do not contain a complex compound used for pigment inks and the like, and are composed of one or more kinds of particles among simple metal particles, metal alloy particles, and ceramic particles. Examples of the solid fine particles 7 include single metal particles such as platinum (Pt) particles and nickel (Ni) particles, and ceramic particles such as zirconium oxide (zirconia / ZrO ₂ ) particles.

  Such a solid fine particle dispersion 10 can be applied as an ink-jet ink for printing by an ink-jet method. For example, it is possible to pattern-print a conductor pattern on a substrate.

  Here, the configuration of the solid fine particles 7, the first dispersant 3, and the second dispersant 5 will be described in detail. As shown in FIG. 1, the solid fine particles 7 are not particularly subjected to a treatment such as surface modification, and have surface physical properties in which acid points 7a and base points 7b are mixed on the particle surface.

  As shown in FIG. 1, the 1st dispersing agent 3 is equipped with the compatible group 3b which produces what is called a steric hindrance. Furthermore, this 1st dispersing agent 3 has only any one of an acidic adsorption group or a basic adsorption group. In the example of FIG. 1, the 1st dispersing agent 3 is provided with the acidic adsorption group 3a. The 2nd dispersing agent 5 is provided with the compatible group 5c, as shown in FIG. Further, the second dispersant 5 is an amphoteric dispersant and has both an acidic adsorbing group 5a and a basic adsorbing group 5b.

  Therefore, in the solid fine particle dispersion 10 of the present embodiment, at least one of the first dispersant 3 and the second dispersant 5 is different from the acid point 7a and the base point 7b on the surface of the solid fine particle 7, respectively. Will be adsorbed. Specifically, as shown in FIG. 1, the basic adsorption group 5 b of the second dispersant 5 is adsorbed on the acid sites 7 a on the surface of the solid fine particles 7. On the other hand, the acidic adsorption groups 3a of the first dispersant 3 and the acidic adsorption groups 5a of the second dispersant 5 are adsorbed on the base points 7b on the surface of the solid fine particles 7, respectively. Furthermore, the acidic adsorption group 3 a of the first dispersant 3 is adsorbed on the basic adsorption group 5 b of the second dispersant 5.

  As a result, the solid fine particle dispersion 10 can adsorb the first dispersant to the surface of the solid fine particles 7 as a whole, and the dispersing action due to the steric hindrance of the first dispersant 3 is effectively functioned. The solid fine particles 7 can be dispersed. In addition, the dispersibility can be enhanced by a decrease in the intermolecular force between the solid fine particles 7 as the area where the dispersant on the particle surface is not adsorbed by the second dispersant 5 decreases. That is, the solid fine particle dispersion 10 can suppress the aggregation of the solid fine particles 7 because the exposure of the particle surface is suppressed as much as possible and the entire surface is covered with the dispersant.

  On the other hand, as shown in FIG. 2, for example, in the solid fine particle dispersion 20 of Comparative Example 1 containing only the first dispersant 3, the dispersant is adsorbed on the acid sites 7 a on the surface of the solid fine particles 7. Therefore, an intermolecular force between the solid fine particles 7 works at the acid point 7a, and as a result, there is a concern about aggregation of the solid fine particles 7. Further, as shown in FIG. 3, for example, the solid fine particle dispersion 30 of Comparative Example 2 containing only the second dispersant 5 (amphoteric dispersant) has an acid point 7a and a base point 7b on the surface of the solid fine particle 7. Although the dispersant is adsorbed on each of them, it is generally difficult to obtain a desired steric hindrance effect only with an amphoteric dispersant having a relatively small molecular weight, and as a result, aggregation of solid fine particles may occur.

  As shown in FIG. 4, the solid fine particle dispersion 40 of another example in which the surface of the solid fine particles 47 is unified at the base point 47b by surface modification or the like and further contains only the first dispersant 3 is solid Although the dispersing agent is adsorbed on the entire surface of the fine particles 47 and aggregation of the solid fine particles can be suppressed, a treatment such as surface modification is required, resulting in an increase in material cost.

  On the other hand, according to the solid fine particle dispersion 10 of the present embodiment, as described above, the dispersibility of the solid fine particles 7 in the dispersion medium can be improved without modifying the surface of the solid fine particles 7. Can do.

  Next, the device 50 according to the present embodiment will be described with reference to FIG. As shown in FIG. 5, the device 50 includes conductor patterns 54 and 55 as solid fine particle sintered films patterned using the solid fine particle dispersion 10 described above on a substrate (base material) 52. .

  An example of the device 50 is a semiconductor device in which a semiconductor element is mounted as an electronic component on a wiring board. Examples of the semiconductor device include a flip chip package, a chip scale package, a multichip package, an antenna switch module, a mixer module, a PLL module, and a multichip module.

  As shown in FIG. 5, as a method of manufacturing the device 50, for example, a conductive pattern 54 having a thickness of about 0.5 μm is first formed on a ceramic substrate 52 by, for example, ink jet printing using the solid fine particle dispersion described above. Form. Next, after a catalyst component is attached to the surface of the conductive pattern 54, electroless copper plating is performed, and the conductive pattern 55 having a thickness of, for example, 25 μm is formed on the plated conductive pattern 54. The pattern is formed by ink jet printing or the like.

  Then, a baking process is performed. Here, the zirconium oxide particles contained in the solid fine particle dispersion together with the platinum particles as solid fine particles suppress the aggregation of the platinum particles at the time of firing, or the shrinkage rate at the time of firing the conductive patterns 54 and 55. For example, it is contained in order to approach the shrinkage rate of the ceramic substrate 52 described above.

  Subsequently, an electronic component such as a semiconductor element is mounted on the substrate 52 including the conductor patterns 54 and 55 that are solid fine particle sintered films, and is electrically connected to the conductor patterns 54 and 55. Thereafter, the device 50 is manufactured by packaging and the like.

  In the device 50 thus manufactured, the dispersibility of the solid fine particles 7 in the solid fine particle dispersion 10 used as the material of the conductor patterns 54 and 55 is enhanced. Therefore, according to the device 50, excellent conduction performance can be obtained from the conductor patterns 54 and 55, thereby ensuring electrical connection reliability.

  Although the present invention has been specifically described above with reference to the embodiment, the present invention is not limited to this embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the case where the solid fine particle dispersion is subjected to pattern printing by the ink jet method has been exemplified. However, instead of this, the solid fine particle dispersion may be applied also when the pattern is formed by the dispenser method.

[Example]
Next, an embodiment of the present invention will be described with reference to FIGS. 6 and 7 in addition to FIGS. Here, FIG. 6 shows a sedimentation test method for evaluating the dispersibility of the solid fine particles in the solid fine particle dispersion. Specifically, as shown in FIG. 6, the solid fine particle dispersion to be evaluated is put into a measuring cylinder with a stopper, and measurement of the time from the initial time point (0 hr) is started. As time passes, the solids settle and the supernatant becomes transparent. After x hours (xhr), the height from the bottom surface of the solid fine particle dispersion in the graduated cylinder to the top surface including the supernatant is confirmed. The total amount A of the solid fine particle dispersion is determined. Furthermore, at this time, the height from the upper surface (the bottom surface of the supernatant) of the settled solid content to the upper surface of the supernatant is confirmed to determine the amount B of the supernatant.

  Thus, the dispersibility of the solid content (solid fine particles) in the solid fine particle dispersion is quantitatively determined by detecting the ratio (B / A) of the supernatant amount B to the total amount A after x hours. Is possible. In other words, in the solid fine particle dispersion, when the dispersibility of the solid fine particles is low, the ratio of the supernatant amount B increases. On the other hand, when the dispersibility of the solid fine particles is high, the ratio of the supernatant amount B decreases.

  Therefore, in this example, the proportion of the supernatant amount B with respect to the total amount A was determined to be, for example, less than 30% as a non-defective product (OK product), and 30% or more was determined to be a defective product (NG product). In addition, the solid fine particle dispersion which can confirm a deposit visually on the bottom of a graduated cylinder was determined as inferior goods (NG goods).

  7 shows the solid fine particle dispersion 10 as the example shown in FIG. 1, the solid fine particle dispersion 20 of the comparative example 1 shown in FIG. 2, and the solid fine particle dispersion of the comparative example 2 shown in FIG. FIG. 7 shows the result of a sedimentation test by the method of FIG. 6 with the body 30 as an evaluation target. Here, the components of the solid fine particle dispersion 10 of the example are, for example, 28 mass% of platinum particles and 4 mass% of zirconium oxide particles with respect to the total mass of the solid fine particle dispersion 10 (in the solid fine particle dispersion). 14% with respect to the mass of the platinum particles), 0.5% by mass of the first dispersant 3, 0.5% by mass of the second dispersant 5, 1% by mass of the binder, and 66% by mass of the non-aqueous dispersion medium. It was.

  On the other hand, the component of the solid fine particle dispersion 20 of Comparative Example 1 is obtained by changing the addition amount of the first dispersant 3 and the second dispersant 5 with respect to the component of the solid fine particle dispersion 10 of the example. Specifically, the first dispersant 3 was increased from 0.5 mass% to 1 mass%, and the second dispersant 5 was changed from 0.5 mass% to 0 mass% (second dispersant 5 Was not added). Further, the component of the solid fine particle dispersion 30 of Comparative Example 2 is obtained by changing the addition amount of the second dispersant 5 and the first dispersant 3 with respect to the component of the solid fine particle dispersion 10 of the example. Specifically, the second dispersant 5 was increased from 0.5 mass% to 1 mass%, and the first dispersant 3 was changed from 0.5 mass% to 0 mass% (first dispersant 3 Was not added).

  As a result of the sedimentation test, as shown in FIG. 7, the solid fine particle dispersion 10 of the example containing both the first dispersant 3 and the second dispersant 5 is a non-defective product (OK product), while the first Both the solid fine particle dispersion 20 of Comparative Example 1 containing only the dispersant 3 and the solid fine particle dispersion 30 of Comparative Example 2 containing only the second dispersant 5 were defective products (NG products). Thereby, the dispersibility of the solid fine particles 7 in which the acid points 7a and the base points 7b are mixed on the surface is obtained by adding both the first dispersant 3 and the second dispersant (amphoteric dispersant) 5 to the dispersion medium. It became clear that it improved.

  3 ... 1st dispersing agent, 3a, 5a ... acidic adsorption group, 3b, 5c ... compatible group, 5 ... 2nd dispersing agent, 5b ... basic adsorption group, 10 ... solid fine particle dispersion, 7 ... solid fine particle, 7a ... acid point, 7b ... base point, 50 ... device, 52 ... substrate, 54, 55 ... conductor pattern.

Claims (5)

A dispersion medium;
Solid fine particles in which acid points and base points are mixed on the surface;
A first dispersant having only one of an acidic adsorbing group and a basic adsorbing group;
A second dispersant having both the acidic adsorbing group and the basic adsorbing group;
A solid fine particle dispersion comprising:   2. The solid fine particle dispersion according to claim 1, wherein the solid fine particles include one or more kinds of particles selected from metal simple particles, metal alloy particles, and ceramic particles.   The solid fine particle dispersion according to claim 1, wherein the solid fine particles are composed of single metal particles and / or non-complex compound particles.   4. The solid fine particle dispersion according to claim 1, wherein the solid fine particle dispersion is an inkjet ink.   A device comprising a solid fine particle sintered film formed in a pattern using the solid fine particle dispersion according to claim 1 on a base material.

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