Hermetic device package for microelectronic frequency selection components.

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to packages for microelectronic frequency selection components such as surface acoustic wave or surface acoustic wave (SAW) devices, in particular containers (housings) suitable for mass assembly of packaged, hermetically sealed devices. ..

【0002】

[Problems to be solved by conventional techniques and inventions]

At present, much effort and expense is spent on research and development on microelectronic frequency selection devices. Examples of devices in this category are thin film surface acoustic wave resonators (FBARs) (see, for example, SBAR filter monolithically integrated with HBT amplifiers, D. Cushman et al., 1990 IEEE Ultrason.Symp., Honolulu.HI, Dec. 1990) and surface acoustic wave devices. As many such devices derive electrical properties from the mechanical action of certain parts of the device, events that affect such mechanical action affect the frequency selection characteristics of the device. Circuits containing this type of device tend to provide fairly compact frequency selection components in the smallest space. However, the volume reduction achieved by improving the packaging technology can be increased by about 100 times as compared with other device packaging methods. These devices cannot be put to practical use unless they are sealed and protected in a suitable sealed package or container (hosing).

【0003】

Conventional packages of the device chips described above tend to be expensive and much larger than sealed devices. Some traditional packages can have dies in small areas within the package, but these packages themselves require excessive space. This is because some such packages use leads that extend beyond the boundaries of the package. These leads often have to be attached to conductors on the surface of the substrate and therefore must be led from these conductors to adjacent packages. This requires that sufficient space be maintained between conventional packages to ensure the necessary electrical and mechanical connections.

【0004】

Conventional die bonding with the use of thermosetting polymers will trap contaminants in the polymer or result in significant outgassing of reaction products from the polymer during heating. Concentration of these contaminants on the surface of the frequency-selective component promotes damping of mechanical vibrations and thus greatly attenuates the desired output signal magnitude, so the contaminants described above can significantly degrade device performance. become.

【0005】

For example, resins outgas a significant portion of these masses during curing. Three major brands of adhesives tested by researchers at John Popkins University gas out 9-36% of their mass during curing (Proc.IEEE Elec.Comp.Conf.IEEE Catalog No.89CH2775) -5, pp.301-308). Such significant outgassing leads to the formation of voids, reduces the strength of the die bond, and leads to the regeneration of heavy organic compounds on the surface of the frequency-selective component.

【0006】

Another problem arises when the automated machining arrangement and assembly of the frequency selection parts described above is achieved. This is due to the bending of the leads as they are inserted into the properly processed holes in the board, leading to unreliable connections to the peripheral circuitry of the component.

【0007】

In addition, frequency selection components require a hermetically sealed environment to operate reliably. This results in the use of metal packages such as TO-5, TO-8 containers and dual in-line packages that are individually resistance or seam welded. Due to the piezoelectricity of the materials required for many types of frequency selection devices such as surface wave filters, surface skimming bulk wave filters, shallow bulk acoustic wave filters, these devices are exposed to temperatures above the Curie temperature of the substrate. must not. The welding technique described above produces a properly sealed sealed package without exposing the die to excessive heat. However, these manufacturing techniques are not suitable for batch processing and therefore result in high costs for the production of large quantities of consumer products.

【0008】

In addition, SAW dies require mounting techniques and materials that do not generate stress on the mounted dies. This stress causes random phase distortion and frequency response distortion in the finished part.

【0009】

Therefore, an object of the present invention is to provide a package for a frequency selection device in which a plurality of packages can be juxtaposed and the final product shape is miniaturized by substantially eliminating wasted space between these packages.

【0010】

Another object of the present invention is to provide a package for a frequency selection device that provides a hermetically sealed environment and occupies as little volume as possible.

【0011】

Further, another object of the present invention is to provide a low-cost and easy-to-manufacture package that can be easily handled by an automatic circuit assembly device and can efficiently mass-produce a product incorporating the above-mentioned device.

【0012】

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention discloses a method for packaging a frequency selection component die, that is, a semiconductor circuit die. The frequency selection component die is glued to a package base, which also has a conductor placed on it with a thermoplastic attachment material. An electrical interconnect is formed from the frequency selection component to the conductor of the package base, and the lid seals the package base. Further, in order to solve the above-mentioned and other problems, a method of packaging a piezoelectric frequency selection component die at the stage of providing a package base in which a conductor is arranged on the thermoplastic frequency selection component die, a surface acoustic wave frequency selection made of a piezoelectric substrate material. A step of providing a component die, a step of arranging a thermoplastic diaphragm material between the package base and the die to form an assembly, wherein the thermoplastic diaphragm material is polyetheretherketone, polysulfone, or poly. Selected from the group consisting of ethersulfone, polyetherimide, polybutylene terephthalate and polycarbonate, the step of heating the assembly to the bonding temperature of the thermoplastic diaphragm material, the package base and said by the thermoplastic diaphragm material. The step of cooling the assembly to achieve a junction with the die, the step of forming an electrical interconnect from the frequency component die to the package base, and the step of sealing the lid to the package base. Provided is a method of packaging a piezoelectric frequency selection component die comprising.

【0013】

[Action]

According to the above-mentioned means, a plurality of packages can be arranged side by side, can be sealed and sealed, and can be easily assembled.

【0014】

[Example]

FIG. 1 is a bottom view of the package base 10 showing a thick film interconnect pad 20 and a through-plated via 25.

【0015】

FIG. 2 is a top view of the package base 10, which package 10 has thick film conductors 30,35,40,45,50,55. Conductors 30,35,40,45,50,55 contact through-plated vias 25 and make electrical connections with interconnect pads 20 on the bottom of the package base 10.

【0016】

FIG. 3 shows a side view of the package base 10, which has a thermoplastic diaphragm material 60 and a frequency selection component such as a surface acoustic wave (SAW) die 70 mounted on the material 60. The thermoplastic diaphragm adhesive 60 can be any of several materials, depending on the melting point required for the particular application. Table 1 shows examples of thermoplastic diaphragm materials 60 and the temperatures required for bonding these examples. Table 1 Adhesion temperature of thermoplastic materials Material Adhesion temperature (° C) Polyetheretherketone 360 (Polyetheretherketone) Polysulfone 300-380 Polyether sulfone 320-380 Polyetherimide 340-380 Polybutylene terephthalate 240 (Polybutylene terepthalate) Polycarbonate 230-290 [0017]

FIG. 4 (A) is a top view of the SAW device die 70, which has bond pad regions 72,74,76,78,80,82. These bond pad regions 72,74,76,78,80,82 are mutually connected to the conductor regions 32,35,42,45,52,55 (Fig. 2) by wire bond 27 ((B) in Fig. 4). It is connected. The wire bond 27 is made in the conductor regions 32, 42, 52 as shown in FIG. 4 (B), but is not covered by the thermoplastic diaphragm material 60 directly under the SAW die 70 and is also As shown in (A) of FIG. 5, the low melting temperature glass 110 is formed on a portion not located at the portion where the cover 100 is mounted on the package base 10. The portion of the conductor area 32,42,52 covered by the thermoplastic attachment material 60 acts as a diaphragm pad, but the diaphragm pad is not always required for the attachment.

【0018】

An example of low melting temperature glass 110 is a mixture of PbO and V2O5. The mixture is heated at 360 ° C for 2 minutes and sealed in package base 10 with a lid 100.

【0019】

FIG. 5 (A) is a top view of the ceramic lid 100, which has a hollow central region 105 as shown in FIG. 5 (B).

【0020】

FIG. 5B is a partial cross-sectional view taken along the AA line of the ceramic lid 100 and the low melting temperature glass 110 of FIG. 5A.

【0021】

FIG. 6 (A) shows a plan view of another embodiment of Package 200, and FIG. 6 (B) is a partial cross-sectional view thereof. In this embodiment, the package base 200 is shown in FIG. 6 (B) and consists of a ceramic material layer 210, which is a gold-plated Kovar (which seals the ceramic material layer 210 with molten glass 220). Kovar) Has a gold-plated Kovar lead 230 within the lead frame 240. The glassless area 201 of the gold-plated Kovar lead 230 in the package base 200 is the interconnect line from the SAW die 70 bonding pads 72,74,76,78,80,82 shown in FIG. 4 (B). Used for 27 bonding.

【0022】

The SAW die 70 is attached to the die bonding pad 250 by the thermoplastic diaphragm material 60, and the electrical connection to the SAW die 70 is made by the wire bond 27 illustrated and illustrated in FIG. 4 (B). After the wire bonding process, the solder preform 260 is placed on top of the top metallization ring 240. The lid 270 is placed on the solder preform 260 and the lid is soldered to the metallized ring 240, whereby the package base 200 is hermetically sealed with the lid 270.

【0023】

An example of a measured SAW transmission frequency response 300 from a SAW device mounted in accordance with the present invention is shown in FIG. The data in FIG. 7 indicates that the device response 300 corresponds to the design of the SAW device and that the packaging method according to the present invention does not interfere with the operation of the SAW device 70.

【0024】

The circuit surface acoustic wave device 70 or the package 200 for a microphone electronic device such as a semiconductor circuit die according to an embodiment of the present invention has a minimum structure 200 obtained by sealing the SAW device in a hermetically sealed environment. Suitable for occupying the space volume of. Package 200 can include a die pad 250 for surface acoustic wave dies 70, and package 200 can accommodate SAW dies 70 without any over-compression or tension on the top surface of SAW dies 70 that can damage the device. Includes a thermoplastic adhesive 60 for fixing to the package base 210. The thermoplastic diaphragm adhesive 60 can expose the SAW device 70 to temperatures higher than conventionally possible temperatures, protecting the SAW die 70 from contamination of the diaphragm adhesive 60 from outgassing. That is, it secures the lid 270 to the package base 200 with solder 260, allowing the SAW die 70 to be hermetically sealed from the external environment. The base 210, thermoplastic die attachment adhesive 60, lid 270, and lid attachment solder 260 work together to provide a package that seals and protects the SAW die 70.

【0025】

The packaging method according to the invention, which is desirable but not necessarily so, comprises the following steps.

【0026】

Steps to form electrical interconnections from the frequency selection component die 70 to the package base conductor 30,35,40,45,50,55, from the frequency selection component die 70 to the package base conductor 30,35,40,45. , 50, 55, including the step of wire bonding, or the step of sealing the package base 10 with the lid 270, by soldering the lid 270 to the package base 10 and hermetically sealing (hermetic). The step of forming a seal), or the step of soldering the lid 270 to the package base 10, including the step of soldering the metal lid 270 to the package base 10, the frequency selection component die 70 is thermoplastic. A step of placing the surface elastic wave device 70 on the thermoplastic attachment material 60, including a step of placing the surface elastic wave device 70 on the thermoplastic attachment material 60, or forming an adhesive between the frequency selection component die 70 and the package base 10. A step that includes a step that removes the heat source from the assembly of the package base 10, the thermoplastic attachment material 60, the frequency selection component die 70, allowing the assembly to cool, or low-firing. -temperature glass) 110 is added to the package base 10, the lid 270 is placed on the low firing temperature glass 110, the low firing temperature glass 110, the package base 10, and the lid 100 are heated to melt the low firing temperature glass 110. , And the low firing temperature glass 110, the package base 10, the step of cooling the lid 100 to form the frequency selection component die assembly of the sealed package, or the step of placing the lid 100 on the low firing temperature glass 110. A step of placing the ceramic lid 100 on the low firing temperature glass 110, or a step of placing the lid 100 on the low firing temperature glass 110 and placing the glass lid 100 on the low firing temperature glass 110. A step of including or bonding a thermoplastic diaphragm material 60 on a package base 10, a step of heating the package base 10 and the thermoplastic diaphragm material 60 to a certain temperature, a frequency selection component die 70. A step of placing on the thermoplastic diaphragm material 60 and a step of cooling the package base 10, the thermoplastic diaphragm material 60, and the frequency selection component die 70, or a heating step, the thermoplastic diaphragm material. A step of heating to a temperature above 60 melting points, or a step of providing a microelectronic circuit die 70, comprising a step of providing a semiconductor circuit die 70, or providing a microelectronic circuit die 70. A step that includes a step that provides a frequency selection component die 70.

【0027】

Devices according to the invention, which are desirable but not necessarily, include the following means: A wire bonding means 27 that provides an electrical interconnect 27 from the frequency selection device means 70 to the conductor means, or a soldering means 260 provided on the package-based means 10, and a package-based means 10 provided on the package-based means 10. Cap means 270, which is soldered to form a sealing seal on the package-based means 10, or cap means 270, which includes a metal cap 270, or frequency-selective device means 70, which includes a surface elastic wave device 70, or on package-based means 10. A low firing temperature glass means 110 provided, and a cap means 100 or a ceramic cap 100 provided on the package base means 10 and melted with respect to the package base means 10 to form a sealing seal to the package base means 10. Cap means 100 including, or cap means 100 including glass cap 100.

【0028】

Although the present invention has been described in the context of a particular embodiment, many changes, modifications and changes will be apparent to those skilled in the art in light of the above description. Therefore, the present invention is intended to include the above-mentioned changes, modifications, and changes within the scope of claims.

【0029】

[Effect of the invention]

As described above, according to the present invention, the shape of the final product can be miniaturized by allowing a plurality of packages to be juxtaposed to substantially eliminate wasted space between these packages, and the final product shape is sealed. A low-cost and easy-to-manufacture package that can provide an environment and a package with the smallest possible volume, and can efficiently mass-produce products that are easily handled by an automatic circuit assembly device and incorporate the above-mentioned devices. Can be provided.

[Simple explanation of drawings]

[Figure 1]

It is a bottom view of the package base which concerns on this invention.

[Figure 2]

It is a top view of the package base which concerns on this invention.

[Fig. 3]

It is a side view of the package base which concerns on this invention which attached SAW.

[Fig. 4]

A surface acoustic wave device is shown, (A) is a top view thereof, and (B) is a top view when mounted on a package base according to the present invention.

[Fig. 5]

The package lid according to the present invention is shown, (A) is a bottom view thereof, and (B) is a partially cut sectional view thereof.

[Fig. 6]

Other examples of the package according to the present invention are shown, (A) is a plan view thereof, and (B) is a cross-sectional view of a part thereof.

[Fig. 7]

It is a figure which shows the SAW filter transfer function measured from the SAW device mounted according to this invention.

[Explanation of symbols]

10 package base 20 Thick film interconnect pad 25 beer or via 27 wire bond 30,35,40,45,50,55 Thick conductor 32,42,52 Conductor area 60 Thermoplastic Attachment Adhesive 70 Surface Acoustic Wave (SAW) Die 72,74,76,78,80,82 Bonding pad area 100 lid 110 Low melting temperature glass 200 packages 201 Glassless area 210 Ceramic material layer 220 molten glass 230 leads 240 lead frame 260 Solder preform 270 lid 300 SAW transmission frequency response