JPS60180317A - Package for saw device or the like - Google Patents

Abstract

PURPOSE:To improve the yield of a product remarkably and to decrease the manufacture unit price by decreasing slightly an insulation resistance between leads connecting an interdigital transducer (IDT) or between a lead and a package case to leak electrostaticity produced between electrode figers of the IDT electrode. CONSTITUTION:A short-circuit fault between device IDTs is prevented almost completely by decreasing the insulating resistance between leads to a proper value. There are various means for decreasing the insulation resistance between leads, but in this invention an antistatic agent 4 is coated on the surounding of the through-part of leads 3, 3 at the outer face of a metallic base 2 without remarkable change of the conventional manufacture process and materials in use. If required, the agent may be coated on both the inner and outer faces. Moreover, when an SAW device 1 or the like stored in a nonconductor base 5 made of ceramic or glass, an antistatic agent pattern film 6 connecting the leads 3, 3 is formed on the surface of the base 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides surface acoustic waves (S-AW) or waves propagating within the bulk of the piezoelectric substrate (for example, The present invention relates to the structure of a device package that generates BSW) and the like.

Conventionally, in devices such as SAW resonators that use < IDT electrodes to generate elastic waves of a desired frequency on a piezoelectric substrate, a short circuit occurs between the IDT electrode fingers after the disassembly process is completed, resulting in failure of the device. There are many accidents in which the device loses its functionality, and it has been discovered that the cause of this is that metal particles present inside the case are somehow attracted by static electricity applied to the surface of the board.

The present invention was made in order to prevent the above-mentioned accidents from occurring in SAW devices, etc., and is intended to prevent the occurrence of accidents such as those described above in SAW devices, etc., between the leads or between the leads and the package case that airtightly penetrate the package housing all the 8AW devices, etc. By slightly lowering the insulation resistance of the SA, the static charge generated between the IDT'i[ij fingers can be easily leaked.
The purpose is to provide a panage of WDeviceX.

Hereinafter, the present invention will be explained in detail based on the theory that led to the invention and examples.

First, in order to help understand the present invention, samples with short circuits and normal samples were extracted from a SAW resonator production loft where short circuits between IDT electrode fingers occurred frequently, and the results were observed under a microscope. In all of the samples tested, metal fine particles were observed to adhere between the II) T electrode fingers.

Incidentally, most of these metal particles are thought to be those that were generated and remained on the inner surface of the package lid during press processing, and those that were scattered during welding between the base and lid of the package. In the test production using the lid body carried out in 2007, a clear decrease in the defective rate7 was observed.

However, even with this method, not only was it not possible to obtain a sufficiently satisfactory rate of non-defective products, there was also a drawback that the cleaning process required a considerable amount of cost.

Therefore, considering the above observation results, it is thought that static electricity is applied between the adjacent electrode fingers of the IDT from a charged tool or a human body through the external lead, but if there are metal particles between them, a gap will be created. Since the particles are extremely small, discharge easily occurs between the electrode fingers and the metal particles, and it is presumed that the short circuit is caused by the connection between the electrode fingers by the molten metal.

If the above estimation is correct, in order to prevent such a phenomenon, the insulation resistance between the IDTs of the device should be slightly reduced to reduce the generated electrostatic charge kIJ-.

Therefore, in the present invention, based on the above-mentioned consideration, as shown in FIG. An experiment was conducted by applying an appropriate amount of antistatic agent 4.

That is, 40 samples were randomly selected from the same production lot, divided into two, and an appropriate amount of a commercially available antistatic agent (trade name: Yugo No. However, the other 20 groups are left untreated.

When the inter-lead insulation resistance of both was measured, it was on the order of IOMΩ in both untreated groups, but it decreased to about 1 to 10MΩ in both treated groups.

Samples from both groups were made into finished products through a regular process, and when they were shaken under the same conditions to check for short circuits, 6 defects occurred in the untreated group, while 1 defected in the treated group. However, when the inter-lead insulation resistance of this defect was measured, the value increased to more than 200 MΩ, and upon further detailed inspection, it was discovered that the antistatic agent had partially peeled off.

This result completely confirms the correctness of the initial assumption. That is, it has been found that short-circuit accidents between device IDTs can be almost completely prevented by lowering the insulation resistance between the leads to an appropriate value.

There are various ways to lower the insulation resistance of leads such as hJ (; IA), but in order to carry out all of these without significantly changing the conventional manufacturing process and usage costs, for example, as shown in Figure 2. Leads 3 on the outer surface of the metal base 2,
An antistatic agent 4 may be applied around the penetration portion 3, or may be applied to both the inner and outer surfaces if necessary.

Furthermore, when the SAW device 1 is housed in a non-conductive base 5 made of ceramics or glass, an antistatic agent pattern film 6 is formed on the surface of the base 5 to connect all the leads 3 as shown in FIG. It's okay.

Although only the case where an antistatic agent is used as a pattern material for lowering the insulation resistance between leads has been described above, it is obvious that the present invention is not limited to the use of all antistatic agents. It's not even a good thing. At this time, since the value of the inter-lead insulation resistance can be determined experimentally, the entire cross-sectional area of the vapor deposition pattern may be appropriately selected accordingly.

Since the present invention is configured and functions as explained above, it is possible to eliminate short-circuit accidents between electrode fingers of a device that uses IDT2 to generate various waves on a piezoelectric substrate. Since it is possible to completely prevent this without making any changes, it is extremely effective in significantly improving the product yield v and reducing the manufacturing cost.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing one embodiment of a package for a SAW device, etc. according to the present invention, Fig. 2 is a side sectional view showing another embodiment, and Fig. 3 is a plan view showing another embodiment. It is a diagram. 1... SAW device, 2-...
・・・Metal base, 3・・・・・・・・・'J-tl
4.6・・・・・・・・・ Pattern for lowering insulation resistance, 5
・・・・・・Non-conductor base

Claims (4)

[Claims] (1) In a pan cage that houses a device that generates elastic waves on the surface of the piezoelectric substrate or in its bulk by means of interdigital transducer electrodes provided on the surface of the piezoelectric substrate, the entire package is airtightly passed through, and the interdigital transducer and By slightly reducing the insulation resistance between the connected leads or between the leads and the package case, the static electricity generated between the electrode fingers of the interdigital transducer electrodes can be leaked, and the static electricity generated by fine metal powder can be transferred between the electrode fingers. All features of S are designed to prevent short circuits caused by adhesion of
Packages for AW devices, etc. (2) When the device is connected to the inside and outside of the package via a lead that hermetically penetrates the conductor base and is electrically insulated from the conductor base, an antistatic layer is provided at least around the lead penetration part on the surface or back surface of the space, or both. A package for a SAW device or the like according to claim 1, characterized in that the entire required amount of agent or conductive paint is applied. (3) When the device is connected to the inside and outside of the package via a lead that hermetically passes through an insulating material base such as glass or ceramics, the surface or the back surface of the space, or the entire surface of both of these, or the leads are connected to each other. The SAW according to claim 1, characterized in that the required pattern is coated with an antistatic agent or a conductive paint.
Packages for devices, etc. (4) A pattern attached to the periphery of the lead penetration portion on the surface or back surface of the paste, or both, or a pattern connecting the leads, is made of a thin film of a single metal or alloy having the required cross-sectional area. A package for a SAW device or the like according to claim 2 or 3, characterized in that the package is formed by: