JPH046283B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a crystal resonator that does not generate cracks and has excellent durability. [Technical background of the invention and its problems] A quartz crystal resonator is a thin quartz crystal piece formed by cutting a quartz crystal body at a predetermined angle, and metal electrodes are provided on a thin quartz crystal piece. It is made by gluing together a crystal piece, then covering it with a cover and sealing it, and is widely used for oscillation. In order to maintain electrical conductivity 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, and to maintain the mechanical connection between the two,
Conductive adhesive is used. Conventionally, a two-component epoxy adhesive has been used as the conductive adhesive. However, conventional conductive adhesives do not have satisfactory properties. For example, if a thin crystal piece for high frequency is bonded with a two-component epoxy-based conductive adhesive, the conductive adhesive covering the crystal piece may cause cracks on the crystal piece after hardening, or the crystal unit may There are drawbacks such as non-oscillation during drop tests. In addition, since it is a two-component product, the pot life after mixing the two components is short, and a large amount of outgas is generated, which reduces adhesion and has other disadvantages. [Object of the Invention] The object of the present invention was to solve the above-mentioned drawbacks, and to provide a product that does not cause cracks or oscillations even in a drop test, and has excellent durability, and further reduces the amount of outgas generated. The aim is to provide a small number of crystal units. [Summary of the Invention] In the present invention, as a result of intensive research to achieve the above object, it was discovered that a conductive adhesive described below can achieve the above object. That is, the present invention provides a quartz crystal characterized in that a metal electrode provided on a quartz crystal piece and a lead-out conductor are bonded with a conductive adhesive containing a urethane prepolymer, a polyhydric alcohol, and a conductive powder as essential components. It is a vibrator. The crystal piece used in the present invention is obtained by cutting a crystal body at a predetermined angle and has a thickness of about 80 μm. The conductive adhesive used in the present invention contains as essential components a binder made of a urethane prepolymer and a polyhydric alcohol, and a conductive powder. As the urethane prepolymer used in the present invention, all prepolymers that form urethane can be used, but preferred are blocked isocyanate prepolymers whose terminal active isocyanate groups are blocked with an active hydrogen compound. Typical examples include polyester or polybutadiene having a terminally active isocyanate, which is blocked with a blocking agent such as acetoacetate, cyclohexanone oxime, or phenol. Specific examples include Desmodule AP Stable (trade name, manufactured by Bayer), Eurotsuk Q-9062 (trade name, manufactured by Idemitsu Petrochemical), etc., which may be used alone or in combination of two or more. These blocked urethane prepolymers are stable at room temperature, but have the property of dissociating isocyanate groups when heated above 120°C. The polyhydric alcohols used in the present invention include:
In consideration of flexibility and pliability, those having long-chain alkyl groups and polyester-based and polybutadiene-based polyhydric alcohols can be used. Specifically, R- manufactured by Idemitsu Petrochemical Co., Ltd.
45HT, Sanyo Chemical's polyethylene glycol, polypropylene glycol, etc., which may be used alone or in combination of two or more. The hydroxyl groups of these polyhydric alcohols react with the isocyanate groups dissociated from the urethane prepolymer. The mixing ratio of the urethane prepolymer and the polyhydric alcohol is such that the ratio of the dissociated isocyanate group (NCO) to the hydroxyl group (OH) of the polyhydric alcohol (NCO/OH) is preferably in the range of 1.0 to 1.2 equivalents. If this blending ratio is less than 1.0 equivalent or more than 1.2 equivalent, the desired characteristics cannot be obtained.
Therefore, it is better to limit it within this range. Further, as a catalyst for promoting this reaction system, dialkyltin dilaurate or the like is generally used. 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. All of these conductive powders preferably have an average particle size of 30 μm or less. If the average particle size exceeds 30 μm, high-density packing becomes impossible, the paste does not form, and coating performance deteriorates. The blending ratio of binder and conductive powder is determined by weight ratio.
The ratio is preferably 30/70 to 10/90. If the amount of conductive powder is less than 70 parts by weight, satisfactory conductivity will not be obtained, and if it exceeds 90 parts by weight, workability and adhesion will decrease. Therefore, it is better to limit it to the above range. In order to adjust the viscosity of the adhesive according to the present invention, an organic solvent may be used as necessary. Examples of the 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, etc. It will be done. The conductive adhesive can be 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 kneaded three times using three rolls to produce one-component conductive adhesives. 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 heat-cured at 150° C. for 30 minutes to produce a crystal resonator. The reaction at this time is complete;
It was observed that the amount of outgas generated after that was small. About this resonator Crystal piece crack and
The number of samples that failed to oscillate when dropped 10 times from a height of 75 cm was measured (total number of samples n = 30), and the results are shown in Table 1. In addition, as a comparative example, 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, and the results are shown in Table 1.

[Table] *2: Polybutadiene with terminal hydroxyl groups manufactured by Idemitsu Petrochemical Co., Ltd. [Effects of the invention] Since the crystal resonator of the present invention uses a conductive adhesive that is flexible and pliable, cracks may not occur. , no failures in drop tests,
It is extremely durable, and because the curing reaction is complete, the amount of outgas generated is small, making it possible to obtain an extremely reliable crystal resonator without adversely affecting other properties.

Claims (1)

[Claims] 1. A metal electrode provided on a crystal piece and a lead-out conductor are bonded using a conductive adhesive containing urethane prepolymer, polyhydric alcohol, and conductive powder as essential components. Crystal oscillator. 2. The crystal resonator according to claim 1, wherein the urethane prepolymer blended into the conductive adhesive has terminal active isocyanate groups blocked with an active hydrogen compound. 3 The ratio of the isocyanate groups (NCO) dissociated from the urethane prepolymer of the conductive adhesive and the hydroxyl groups of the polyhydric alcohol (NCO/OH) is
The crystal resonator according to claim 1 or 2, wherein the amount is in the range of 1.0 to 1.2 equivalents.