JPH0413882B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a crystal resonator that has excellent durability and is free from cracks and transmission failures. [Technical background of the invention and its problems] A quartz crystal resonator is a thin quartz piece made by cutting a quartz crystal at a predetermined angle, and a metal electrode is provided on the thin quartz piece, and a drawer extending from the lid plate of the case and the metal electrode are attached. It is widely used for oscillation, etc. by gluing the conductor and putting a cover over the assembled crystal piece to seal it.
A conductive adhesive is used between the electrode of the crystal resonator and the lead-out conductor, or between the pad of the semiconductor device and the lead-out conductor, in order to maintain electrical conductivity and mechanical bonding between the two. As this conductive adhesive, a two-component epoxy adhesive has conventionally been used. However, conventional conductive adhesives do not have satisfactory properties. For example, if a thin crystal piece for high frequency is glued with a two-component epoxy conductive adhesive, the conductive adhesive covering the crystal piece may cause cracks on the crystal piece after hardening, or the crystal unit may become damaged. There are drawbacks such as some cases not oscillating in drop tests. In addition, since it is a two-component product, it has short pot life after mixing the two components, and a large amount of outgas is generated, which reduces adhesion and affects other products. Furthermore, if a flexible resin having unsaturated double bonds such as polybutadiene is used, the above-mentioned problems of cracking of the crystal piece and failure of transmission due to a drop test will not occur in the initial stage.
However, if exposed to high temperatures of 100℃ or higher for a long period of time, the unsaturated double bonds in polybutadiene will be oxidized and polymerization will proceed on the surface, causing it to lose flexibility and cause cracks and poor transmission, similar to epoxy resin. It was hot. [Object of the Invention] The object of the present invention has been made to eliminate the above-mentioned drawbacks, and it not only eliminates the occurrence of cracks and non-oscillation in the drop test in the normal test during adhesion, but also improves the estimated lifespan. The aim is to provide a highly durable crystal resonator that exhibits excellent characteristics even in accelerated heating tests. [Summary of the Invention] The present inventors previously proposed adhesive fixing with a urethane-based conductive adhesive containing a urethane prepolymer, a polyhydric alcohol, and a conductive powder (Japanese Patent Application Laid-open No. 77411/1983). However, the above objective was achieved by specifically identifying the skeletons of urethane prepolymers and polyhydric alcohols as hydrogenated polybutadiene skeletons, which are hydrogenated polybutadiene skeletons to eliminate unsaturated double bonds. We have discovered what can be achieved and have completed the present invention. That is, the present invention provides a method for connecting the metal electrode provided on the crystal piece and the lead-out conductor of the component to a conductive material containing a urethane prepolymer of hydrogenated polybutadiene, a polyhydric alcohol of hydrogenated polybutadiene, and a conductive powder as essential components. This is a crystal resonator characterized by being fixed with adhesive. The above urethane prepolymer is one in which the terminal active isocyanate groups are blocked with an active hydrogen compound, and the isocyanate groups (NCO) dissociated from the above urethane prepolymer are combined with the hydroxyl groups (OH) of the above polyhydric alcohol. The ratio (NCO/OH) is in the range of 1.0 to 1.2 equivalents. The crystal piece used in the present invention is a thin piece with a thickness of about 80 μm obtained by cutting a crystal body at a predetermined angle.
The size is not particularly limited. The urethane prepolymer of hydrogenated polybutadiene used in the present invention is a urethane prepolymer in which backbone polybutadiene is hydrogenated (that is, unsaturated double bonds are eliminated), and its terminal active isocyanate groups are blocked with an active hydrogen compound. Blocked isocyanate prepolymers are preferably used. Blocking agents include acetoacetate, cyclohexanone oxime, phenol, imidazole, and the like. Specific brands include hydrogenated polybutadiene-based phenol-blocked isocyanate prepolymer manufactured by Nippon Soda Co., Ltd., and the like. Blocked urethane prepolymers are stable at room temperature, but have the property of dissociating isocyanate groups when heated above 120°C. The polyhydric alcohol of hydrogenated polybutadiene used in the present invention is a polyhydric alcohol obtained by hydrogenating the backbone polybutadiene (that is, eliminating unsaturated double bonds).
Examples include hydrogenated polybutadiene with a terminal hydroxyl group, manufactured by Nippon Soda Co., Ltd. The polyhydric alcohol of the hydrogenated polybutadiene is reacted with the isocyanate group dissociated from the urethane prepolymer of the hydrogenated polybutadiene to form a binder. Dialkyltin dilaurate or the like is generally used as a catalyst to promote this reaction system. The blending ratio of the urethane prepolymer of hydrogenated polybutadiene and the polyhydric alcohol of hydrogenated polybutadiene is determined by the equivalent ratio (NCO/OH) of the dissociated isocyanate groups (NCO) of the urethane prepolymer and the hydroxyl groups (OH) of the polyhydric alcohol.
It is preferably in the range of 1.0 to 1.2. This ratio
If it is less than 1.0 or more than 1.2, the desired characteristics cannot be obtained and it is undesirable, so it is limited to the above range. The conductive powder used in the present invention includes silver powder,
Examples include copper powder, nickel powder, and powder having a metal layer on the surface, and these may be used alone or in a mixture of two or more. It is preferable that all conductive powders have an average particle size of 30 μm or less. If the average particle size exceeds 30 μm, it is not preferable because high-density packing becomes impossible and the paste does not form, and coating performance deteriorates. The blending ratio of the binder and the conductive powder is preferably 30/70 to 10/90 by weight. If the amount of the conductive powder is less than 70 parts by weight, satisfactory conductivity cannot be obtained, and if it exceeds 90 parts by weight, workability and adhesion deteriorate, which is not preferable. Therefore,
limited to the above ranges. For the conductive adhesive used in the present invention, an organic solvent can be used as necessary to adjust the viscosity. These solvents include dioxane, hexanone, benzene, toluene, solvent naphtha, industrial gasoline, cellosolve acetate, ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, butyl carbitol acetate, dimethylformamide, dimethylacetamide, N
-Methylpyrrolidone and the like. The conductive adhesive is manufactured by thoroughly kneading the above-mentioned components using a three-roll roll or the like. [Embodiments of the Invention] Next, embodiments of the present invention will be described. Examples 1 to 3 Each component shown in Table 1 was prepared using three rolls.
One-component conductive adhesives were manufactured by kneading the mixture twice. The thus obtained adhesive was dispensed onto the electrode portion of a crystal piece with a thickness of 80 μm and the pad portion of the semiconductor device, and then heated and cured at 150° C. for 30 minutes to produce a crystal resonator. It was observed that the reaction at this time was complete, and that the amount of outgas generated thereafter was small. Regarding this vibrator, the number of samples that failed to emit when the crystal piece was cracked and dropped 10 times from 75 cm above was measured (total number of samples n=30), and the results are shown in Table 1. Comparative Example 1 A one-component conductive adhesive was manufactured using each component shown in Table 1 in the same manner as in Examples 1 to 3, a crystal resonator was manufactured in the same manner, and the characteristics were tested in the same manner. Therefore, the results are shown in Table 1. In addition, as Comparative Example 2, Examples 1 to 2 were prepared using a two-component epoxy conductive adhesive using a polyamide curing agent.
A crystal resonator was manufactured in the same manner as in Example 3, and its characteristics were measured in the same manner. The results are shown in Table 1.

【table】

[Table] [Effects of the Invention] The crystal resonator of the present invention uses urethane-based conductive adhesives having flexibility and pliability, especially urethane prepolymers of hydrogenated polybutadiene and polyhydric alcohols of hydrogenated polybutadiene. When bonding (normal characteristics in Table 1)
Not only was there no cracking in the drop test nor any failure in the drop test (this is a characteristic of urethane-based conductive adhesives that is also common to Comparative Example 1), but the accelerated heating test at 150℃ for 3 days, which is the estimated lifespan, was confirmed. Also, the durability is significantly improved compared to the non-hydrogenated polybutadiene skeleton urethane conductive adhesive mentioned in Comparative Example 1. Furthermore, since the curing reaction was complete, the amount of outgas generated was small, and other properties were not adversely affected, making it possible to obtain an extremely reliable crystal resonator.

Claims (1)

[Claims] 1. The metal electrode provided on the crystal piece and the lead-out conductor of the component are made of a urethane prepolymer of hydrogenated polybutadiene, a polyhydric alcohol of hydrogenated polybutadiene,
A crystal resonator characterized in that it is adhesively fixed with a conductive adhesive containing conductive powder as an essential component. 2. Claim 1, wherein the urethane prepolymer of hydrogenated polybutadiene is obtained by blocking terminal active isocyanate groups with an active hydrogen compound.
Crystal oscillator described in section. 3. A patent claim in which the ratio (NCO/OH) of isocyanate groups (NCO) dissociated from the urethane prepolymer of hydrogenated polybutadiene to hydroxyl groups (OH) of the polyhydric alcohol of hydrogenated polybutadiene is in the range of 1.0 to 1.2 equivalents. The crystal resonator according to the first or second item of the range.