WO2001033631A1 - Package for high-frequency device - Google Patents

Abstract

A package for a high-frequency device, characterized in that high-precision electrodes are provided on both sides of a fired ceramic substrate, a cured sealing auxiliary layer of an organic polymer material or an inorganic material is formed along the periphery, a device is mounted on the substrate surrounded by the sealing auxiliary layer and electrically connected to the electrodes, and a cap member is bonded to the sealing auxiliary layer with an adhesive gas-tightly. The package can be manufactured and inspected at low cost and used in high-frequency range including the millimeter-wave band (20 100GHz).

Description

 Specification

Technical field for high-frequency device packages

 The present invention relates to a high-frequency element package, a method for manufacturing the same, and a method for packaging a high-frequency element. Background art

 The spread of high-frequency equipment is remarkable, and the number of mobile phones operated exceeds 150 million units worldwide. The operation of next-generation mobile phones is scheduled to begin in the spring of 2001. Digital satellite broadcasting also started in the fall of 2000, and in the 21st century, high-frequency equipment is about to grow significantly again. High-frequency semiconductors such as surface acoustic wave (SAW) filters or MMICs (Microwave Monolithic Integrated Circuits) and GaAsFETs are indispensable for such high-frequency devices. Is being developed and improved.

 In these high-frequency semiconductor devices, for example, in a SAW filter, the velocity of surface acoustic waves changes depending on the humidity, and GaAs, a non-oxide semiconductor, oxidizes in the air and does not exhibit high-performance characteristics. Therefore, it is indispensable to maintain the conditions in which the flow of moisture or oxygen in the atmosphere is cut off. Resin encapsulation is commonly used in low-frequency semiconductor devices for this purpose, but resin encapsulation cannot be used for SAW filters due to its principle. For other high-frequency devices, resin encapsulation is not preferred in the high-frequency band because the dielectric constant of the sealing material adversely affects the characteristics.

For this reason, generally, a high-frequency element is hermetically sealed in dry air or an inert gas such as nitrogen or a rare gas using a hollow ceramic package. As a hermetic sealing structure, a structure in which a high-frequency element is sealed in a metal case is known. However, the use of a metal case or the like is limited because it is expensive and it is difficult to reduce the size and weight.

 A structure is also known in which a high-frequency element is mounted on a substrate, and then a lid made of ceramic, metal, or the like is bonded to the substrate using solder, low-melting glass, thermosetting resin, or the like.

 However, when a cap-type (that is, a U-shaped or arc-shaped cross section) lid is used, the end surface of the lid is bonded to the substrate with a bonding material such as solder frit glass, so that the elements on the substrate are thermally heated. May be damaged by the A sealing method in which the cap-type lid is bonded to the substrate with an adhesive is also being studied. And the airtightness deteriorates over time. For this reason, it has not been used practically until now.

 Therefore, conventionally, a structure in which a ceramic package having a bottom surface and a wall body is formed by using a lamination technique, and an open upper surface is sealed with a lid (lid) has been widely used (for example, see Japanese Patent Application Laid-Open No. H10-163873). No. 135661).

 A typical structure of a conventional multilayer ceramic package is shown in Figs. 10 (a) and (b).

(All are cross-sectional views).

In FIG. 10, the laminated ceramic package 60 has a laminated structure in which the central portion is a single layer and the periphery is two to three layers, and the latter forms a stepped wall. The high-frequency semiconductor element (bare chip) 61 is mounted in a concave part (on the first layer in the figure) in the center of the package, and is wire-bonded to the electrode or conductor line 62 formed on the shelf (the second layer). Connected by A third layer is further provided on the edge of the package, and the lid 65 (usually a metal lid) is seam-welded to the element via, for example, a seal ring 64, thereby affecting the element. Airtight sealing is realized without any problems, and high airtightness is maintained inside. It should be noted that the laminated structure may have two layers, or may have four or more layers. The signal transmission line 62 such as a strip line formed on the shelf is connected to external electrodes 66 provided on the side and bottom surfaces of the package 60 (FIG. 10 (a)), Are connected to the external electrodes 66 by filling vias or through holes 67 provided through the bottom surface of the substrate (FIG. 10 (b)). Thereby, input / output of a high-frequency signal to / from the element (bare chip) 61 is performed.

 In such a conventional multilayer ceramic package, a conductive paste is printed on a ceramic green sheet formed in a predetermined shape in a thick film, these sheets are laminated, cut into individual pieces, and then, It is formed by firing the electrodes and conductor lines simultaneously with firing the green sheet. Therefore, (1) the mounting area of the element, (2) the internal electrode for mounting the element (bare chip), the external electrode for connecting the packaged element module to the external circuit, and the connection between the internal and external electrodes It has the advantage that the conductor line and (3) the support for the sealing lid can be formed simultaneously by applying a conventional lamination technique.

However, it is known that in the package of the conventional structure, the signal characteristic degradation is large in a high frequency region exceeding 10 GHz. For this reason, a package structure that is compatible with the millimeter-wave band (20 to 100 GHz) by applying a thick-film printed coplanar waveguide to the input and output transmission lines in the multilayer ceramic package. Various proposals have been made (for example, JP-A-10-303333). However, although a coplanar waveguide is suitable for high-frequency transmission, it is generally difficult to design, and its structure becomes complicated when used in a multilayer ceramic package. In addition, the package is inevitably accompanied by parasitic capacitance due to wiring and bonding wires included in the package. However, the impedance given by the parasitic capacitance increases as the frequency increases, and the influence increases. This can be corrected by a capacitor or the like, but in a conventional stacked package, it is difficult to correct the impedance with high accuracy because the parasitic capacitance differs for each package. In addition, the mounting of the correction capacity further complicates the package structure. Further, in the conventional package manufacturing method and packaging method, a package piece of a millimeter order is baked, an element is mounted on the package piece, wire-bonded, and a lip is welded. In other words, it was necessary to handle micro ceramic packages and semiconductor chips, etc., and miniaturization of components had increased production costs. In addition, since the internal electrodes for mounting the elements are arranged in recesses in the package, the inspection requires the manufacture of jigs and inspection pads for each product. Furthermore, in order to automate the inspection, an inspection device including a large-scale positioning device suitable for handling minute components is required. In addition, due to the inability to configure the jig, it was practically difficult to perform temperature characteristics and other precise inspections on individual packages.

 An object of the present invention is to solve the above-described problems in the high-frequency package according to the related art, which can be manufactured and inspected at low cost, and has a millimeter wave band (20 to 100 GH). An object of the present invention is to provide a high-performance package structure that can be used even in a high frequency region including z). Another object of the present invention is to provide an inexpensive and efficient manufacturing method and a packaging method for such a high-performance high-frequency package. Disclosure of the invention

The present inventors have studied the above-mentioned problems in a package having a multilayer substrate structure, which has been conventionally considered to be necessary for hermetic sealing at a required level for a high-frequency element. Since the formation of the electrodes and conductor lines by firing is performed simultaneously with the firing of the substrate material, dimensional fluctuations and non-uniformity of the conductors due to shrinkage of firing of the substrate material are inevitable, which causes signal degradation in the high frequency band. It was also concluded that this was one of the main causes of the parasitic capacitance variation (non-uniformity) from package to package. (1) In the package of the high-frequency element, the electrodes necessary for mounting the element, the input / output conductor lines and the Z or circuit are provided on the fired ceramic substrate, and the cured organic polymer material or inorganic material is provided. By bonding the cap-type lid with an adhesive via a sealing auxiliary layer made of a material, a high-level hermetic seal is achieved, and a package exhibiting excellent characteristics in a high frequency band can be realized. (2) In particular, in the structure of (1), a high-precision line width and line length of the conductor line can be obtained. Therefore, by using a strip line for impedance correction, stable impedance can be obtained even at high frequencies. We have found that fine adjustment is possible and that high characteristics can be realized for high-frequency semiconductors such as GaAs FETs and MMICs. (3) A plurality of package regions are provided on the fired substrate, and a package substrate structure according to the above (1) to (2) is formed for each region, and element mounting and hermetic sealing with a cap member are performed. After that, the process of dividing into individual pieces is adopted to improve the efficiency of the manufacturing process. In addition, by applying the semiconductor A8 inspection technology to such an assembled substrate, the inspection efficiency is improved-advanced ( Precision inspection and temperature characteristic inspection), and completed the present invention.

 That is, the present invention provides the following high-frequency element package, a method of manufacturing the same, and a method of packaging the high-frequency element.

[1] (a) a ceramic substrate having a high-frequency element mounting area; and (b) a shape and height that form a space large enough to accommodate the element when brought into close contact with the surface of the substrate. A package for a high-frequency element including a cap member, wherein the ceramic substrate includes: an internal electrode for mounting the element formed after firing of the substrate material; an external electrode; a conductor line connecting between the electrodes; and an element mounting area. A sealing auxiliary layer made of a cured body of an organic polymer material or an inorganic material provided in a shape compatible with the end face of the cap member between the substrate and the portion; After being electrically connected to the cap member A package for a high-frequency element, wherein the package is hermetically sealed by adhering to a cured organic polymer material layer with an adhesive.

 [2] The high-frequency element package according to [1], wherein the sealing auxiliary layer has a surface activated by ultraviolet irradiation or plasma treatment.

 [3] The package for a high frequency device according to [1], wherein the organic polymer material includes a resin selected from an epoxy resin, a phenol resin, and an epoxy phenol resin.

 [4] The package for a high-frequency device according to the above item 1, wherein the inorganic material is crystallized silica glass.

 [5] The high-frequency element package according to the above item 1, wherein the impedance of the packaged element is optimized by the conductor line.

 [6] The high-frequency element package according to [1], wherein the conductor line includes a high-precision distributed constant line formed by forming a thin film.

 [7] The package for a high-frequency element according to the above item 1, wherein the conductor line includes a coplanar line.

 [8] The high-frequency element package according to the above item 1, wherein the ceramic substrate is selected from alumina or a dielectric material having a higher dielectric constant than alumina.

 [9] The package for a high-frequency device according to the above item 1, wherein the cap member is selected from a ceramic, a metal, and a polymer material.

 [10] The high-frequency element package according to [1], wherein a circuit including a spiral inductor and / or a chip capacitor is provided on the surface of the substrate.

 [1 1] The package for a high-frequency device according to the above 1, wherein the device is a SAW filter, Ml MMIC or GaAs FET.

[12] The SAW filter package according to item 11, wherein the element is a SAW filter, and the substrate has a balanced-unbalanced conversion circuit. [13] The element is a GaAs FET, and the conductor lines connected to the gate (G) and the drain (D) are on a straight line, and the distributed constant line connected to the source (s) is orthogonal to this. 11. The GaAs FET package according to the item 11, wherein the GaAs FET is provided on the substrate.

 [14] A plurality of element mounting regions connected by conductor lines are provided on a substrate, and the whole including these elements or one or more of these elements that need to be hermetically sealed by the cap member. 2. A high-frequency module package sealed by the package structure according to 1.

 [15] A step of forming an internal electrode for mounting an element, an external electrode, and a conductor line for connecting between them on a fired ceramic substrate; sufficient contact with the surface of the substrate to accommodate the element Forming a cap member having a shape and a height to form a space having a size; and an organic polymer material having a shape at least between the internal electrode and the substrate portion that is compatible with the end face of the cap member. 15. The method for producing a high-frequency element package according to any one of the above items 1 to 14, comprising a step of printing and curing a layer or providing an inorganic material layer.

 [16] The method of manufacturing a package for a high-frequency device according to the above [15], further comprising a step of activating the surface of the cured organic polymer material layer or the inorganic material layer by ultraviolet irradiation or plasma treatment.

[17] a step of forming a plurality of package substrate regions by providing vertical and horizontal dividing lines including a through-hole on a ceramic substrate; a step of forming a conductor path for conducting the front and back surfaces of the substrate through the through-hole; Forming an internal electrode for mounting an element and a conductor line connecting the internal electrode and the conductor path in the through hole on the surface on the side where the element is mounted in each substrate region: a surface on which the element is mounted in each substrate region; Forming an external electrode on the opposite surface to be electrically connected to the conductor path in the through-hole; in each substrate region, a space large enough to accommodate the element when brought into close contact with the substrate surface Having a shape and height to form Forming a cap member; in each substrate region, printing and curing an organic polymer material layer in a shape compatible with the end surface of the cap member at least between the internal electrode and the edge of the substrate region; A package substrate according to any one of the above items 1 to 15, including a step of providing a material layer; and a step of dividing the substrate along the division line. And a method for manufacturing a high-frequency device package as a cap member.

[18] The method for manufacturing a package for a high-frequency element according to [17], further comprising a step of activating the surface of the cured organic polymer material layer or the inorganic material layer by ultraviolet irradiation or plasma treatment prior to the bonding step.

 [19] The method for manufacturing a high-frequency element package according to the item 17 or 18, further comprising a step of inspecting electrical characteristics of each substrate region before the division.

[20] The method for manufacturing a high-frequency element package according to item 19, wherein the inspection is performed using a semiconductor prober prober.

[21] a step of forming a plurality of package substrate regions by providing vertical and horizontal dividing lines including a through hole on a ceramic substrate; a step of forming a conductor path for conducting the front and back surfaces of the substrate through the through hole; Forming an internal electrode for mounting the element and a conductor line connecting the internal electrode and the conductor path in the through-hole on the surface on the side where the element is mounted in each substrate region; Forming an external electrode on the opposite surface to be electrically connected to the conductor path in the through-hole; in each substrate region, a space large enough to accommodate the element when brought into close contact with the substrate surface Preparing a cap member having a shape and a height to form a cap; at each substrate region, at least an end of the cap member between the internal electrode and an edge of the substrate region; A step of printing and curing an organic polymer material layer in a shape compatible with the above, or providing an inorganic material layer as a sealing auxiliary layer; in each substrate region, a high-frequency element is mounted and electrically connected to the internal electrode. After connecting the cap member to the sealing auxiliary layer with an adhesive A method for packaging a high-frequency element, comprising: bonding and hermetically sealing; and dividing the substrate along the division line.

 [22] The method for packaging a high-frequency device according to the item 21, further comprising a step of activating the surface of the cured organic polymer material layer or the inorganic material layer by ultraviolet irradiation or plasma treatment prior to the bonding step.

 [23] The packaging method for a high-frequency element according to the above item 21 or 22, further comprising a step of inspecting electrical characteristics of each substrate region at any stage before the division.

 [24] The packaging method for a high-frequency device according to the above item 23, wherein the inspection is performed using a semiconductor prober prober. BRIEF DESCRIPTION OF THE FIGURES

 FIGS. 1 (a) and 1 (b) are a plan view and a cross-sectional view, respectively, schematically showing the substrate structure of the high-frequency element package of the present invention.

 2 (a) and 2 (b) are a plan view and a cross-sectional view, respectively, which schematically show the sealing structure of the high-frequency element package of the present invention.

 FIG. 3 is a perspective view schematically showing a packaging process of a high-frequency device according to the present invention.

 FIG. 4 is a plan view schematically showing the structures of the strip line and the coplanar line.

 FIG. 5 is a plan view schematically showing a conventional microphone opening X structure.

 6 (a) and 6 (b) are a plan view schematically showing the micro X structure according to the present invention and a side view excluding a part of the sealing structure, respectively.

FIG. 7 (a) is a side view schematically showing the structure of the distributed constant type GaAsFET package according to the present invention (however, excluding a part of the sealing structure). FIG. 7 (b) and FIG. (c) is a plan view schematically showing two types of structures corresponding to (a). FIG. 8 is a circuit diagram showing an example of a balanced-unbalanced conversion circuit.

 FIG. 9 is a plan view schematically showing the structure of a package with a built-in balanced-unbalanced conversion circuit according to the present invention.

 FIG. 10 is a cross-sectional view schematically showing a structure of a conventional high-frequency element package as ω and (b) according to a difference in a connection structure with an external electrode.

 FIG. 11 is an explanatory view schematically showing a collective substrate packaging process for a high-frequency device according to the present invention.

 FIG. 12 is an explanatory view schematically showing a packaging substrate packaging process of the high-frequency device according to the present invention, following FIG.

 FIG. 13 is an explanatory diagram that schematically shows a packaging substrate packaging process of the high-frequency device according to the present invention, following FIG. 12.

 FIG. 14 is a schematic diagram showing a comparison between a 10 GHz band oscillator according to the prior art and a 10 GHz band oscillator according to the present invention.

High frequency device package

 1 and 2 show the basic structure of the high-frequency element package 10 of the present invention. FIG. 1 schematically shows the package substrate 1 before sealing (FIG. 1): a plan view showing an element mounting surface. FIG. 1 (b) is a cross-sectional view of the package substrate of FIG. 1 (a) taken along the line AA ′ in the figure), and FIG. 2 is a state in which the element is sealed using a cap member 8. It is a top view and a sectional view. Fig. 3 schematically shows the flow of manufacturing and packaging of this package.

As shown in FIG. 1 (corresponding to FIG. 3 (d)), the package substrate 1 of the present invention is used for performing input and output to and from the fired ceramic substrate having the element mounting area 2. And electrodes or conductor lines and Z or circuit (inner electrode 3 for mounting bare chip, outer electrode 6 for package mounting and conductor line 4 and side electrode 5 connecting between them) along the outer periphery of element mounting area 2. And a sealing auxiliary layer 7 made of a cured body of an organic polymer material or an inorganic material. Preferred Alternatively, the sealing auxiliary layer is subjected to a surface activation treatment. As shown in FIG. 1, the internal electrode 3 and the conductor line 4 may be integrated.

 As shown in FIG. 2, the high-frequency element 11 is mounted at the center of the element mounting area 2, and the electrodes 13 on the element surface and the package internal electrodes 3 are connected by bonding wires 12 (see FIG. Thereafter, the cap member 8 is sealed by bonding the cap member 8 to the sealing auxiliary layer 7 of the substrate using an adhesive 9 (corresponding to FIG. 3 (f)). In these figures, the sealing auxiliary layer 7 and the adhesive layer 9 are drawn to have the same width as the end face of the cap member, but the sealing layer composed of the sealing auxiliary layer 7 and the adhesive layer 9 is As long as the high-frequency characteristics are not affected, the substrate may have a larger spread on the substrate surface.

 With the above structure, the electrodes and conductor lines are not affected by dimensional fluctuations caused by shrinkage of the substrate material due to firing shrinkage, so it is possible to incorporate high-level impedance adjustment and other functions using strip lines, etc. , And a high level of sealing can be realized.

 The embodiment shown in FIGS. 1 and 2 shows the most basic embodiment of the present invention, and the shape of the substrate and the structure of the conductor line are changed as necessary. Hereinafter, the substrate structure, the cap member, and the adhesive layer, which are basic elements of the package of the present invention, will be described in detail with reference to typical application examples.

 (a) Substrate structure

 The substrate structure in the package of the present invention includes a fired substrate (a fired ceramic substrate is simply referred to as a “ceramic substrate” unless otherwise noted) and the elements provided on the surface thereof. It includes electrodes, conductor lines, and Z or circuits for input and output of the I / O.

A conventional multilayer ceramic package also includes a structure in which ceramic is used as a substrate material and electrodes, conductor paths, and the like (hereinafter, also simply referred to as “electrodes”) are provided thereon. However, conventional multilayer ceramic packages, as described above, A thick paste of conductive paste is printed on the green sheet and the electrodes are formed by firing the green sheet simultaneously with firing.Since shrinking of the green sheet is inevitable during firing, the parasitic capacitance of the package is reduced for each piece. different. This non-uniformity (variation) is mainly due to poor uniformity in the shrinkage of the electrodes co-fired in the production of the multilayer ceramic package, making it difficult to form electrodes with high precision.

 Therefore, it is essential to increase the uniformity of the shrinkage rate in order to improve the performance of multilayer ceramic packages. Generally, the improvement is due to the improvement of molding technology and firing technology, which are specific to ceramics. However, the non-uniformity of the shrinkage rate cannot be solved because it is derived from the inherent characteristic of ceramics called “baking”. In contrast, in the present invention, a conductor path is provided on a fired substrate instead of forming a laminated substrate from a green sheet, thereby eliminating the process of “simultaneous firing of ceramics and electrodes”. This enabled the formation of the package, thereby suppressing variations in the parasitic capacitance of each package, and further improving the package characteristics and improving the performance, such as impedance correction using a strip line. (a-1) substrate

 As the substrate material, various ceramic materials can be used, but a material satisfying the following conditions is particularly preferable.

 • The element (bare chip) to be mounted must have the same coefficient of linear expansion.

 · It should be possible to form electrodes with high accuracy that satisfies practical use at low cost and easily.

 • Low dielectric loss (high Q value) for effective insulation at high frequencies. • Sufficient mechanical strength even in the case of manufacturing in a collective board state until the final inspection (described later).

As a substrate material meeting the above conditions, alumina, particularly 96 alumina containing 96% by weight of alumina can be mentioned. A dielectric material having a dielectric constant and a Q value higher than that of alumina may also be used. Depending on the purpose, lower inorganic dielectric Body materials can also be used.

 The thickness of the substrate is selected according to the dimensions of the substrate and the required strength. The dimensions and shape of the substrate are determined by the size of the element to be mounted.

 (a-2) Electrode and conductor line

 The electrodes and the conductor lines for inputting and outputting to the substrate and the elements provided on the surface thereof include internal electrodes and packages for connection to the elements as shown in FIGS. 1 and 2. It includes external electrodes (including side electrodes) provided for surface mounting, and conductor lines connecting between the internal and external electrodes.

 These electrodes and conductor lines can be formed by, for example, thick film printing. Further, in the present invention, since there is no step of “firing” after the formation of the electrode, a highly accurate electrode formation by thin film formation and other metallization methods can be used. The conductor material may be a conventional one. For example, for thick film printing, conductive paste for thick film such as Ag, Ag—Pt, Ag—Pd, Au, Cu, and Ni, and for thin film formation. Examples include, but are not limited to, Au, Cu, A and Ni, and the like. These methods may be combined. For example, as the above-mentioned internal electrode and / or external electrode, a material obtained by applying an electroless plating (for example, an electroless gold plating) on a thick-film printed electrode is preferably used. . Applying electroless gold plating has the effects of (1) improving wire bonding, (2) improving solderability, and (3) improving conductor resistance.

 The internal and external electrode shapes may be the same as those of the conventional package. 1 and 2 show the mode of electrically connecting the element and the package by bonding wires, but other connection structures such as a bump structure may be used, and the internal electrodes are shaped according to each connection structure. . In addition, FIGS. 1 and 2 show a mode of connection with the internal electrode-conductor line-side electrode-external electrode, but a filled through hole may be used instead of the side electrode.

As a conductor line, in the high frequency band, a flat line (strip line, Cross-trip lines, coplanar lines) are typical applications.

A stripline can be formed by providing a conductor line with an appropriate line width on the surface of the substrate and providing ground (GND) on the backside of the substrate (Fig. 4 (a)). For example, on a 0.64 mm thick 96-alumina substrate, the line width d is 0.641 ^ 01. A strip line with a characteristic impedance of 50 Ω can be formed by providing a conductor line consisting of a t-force and GND on the entire back surface. As will be described later, from the transmission characteristics (S _{2 I} ) and reflection characteristics (S _M ) of this thick-film printed strip line, even at 10 GHz, the insertion loss is 4% in power (from transmission characteristics S = —0.2 dB). The reflection characteristics are 1.02 or less in terms of standing wave ratio (converted from the reflection characteristics S _u = -42 dB), and the transmission characteristics are lossless and non-reflective, and are excellent for application in the 10 GHz band.

 It is difficult to obtain practically satisfactory characteristics at 15 GHz or higher with thick-film printed striplines. However, in the present invention, it is easy to form a high-precision thin-film electrode pattern by a photoresist method or the like. By providing a high-precision strip line in this system, it is possible to realize high characteristics up to the millimeter wave band of 100 GHz. As described later, the use of coplanar lines is also possible.The use of strip lines, which have a simpler structure than coplanar lines, are easy to design, and have a wealth of know-how, are available at low cost for millimeter-wave band modules. This is advantageous in achieving both high performance and high performance.

 Fig. 4 (b) shows the structure of a coplanar waveguide. This is one in which conductor layers are provided on both sides of the transmission line in Fig. 4 (a). Although the figure shows a structure in which the conductor layers on both sides are connected to the GND layer on the back via a through hole, a structure without a GND layer on the back or a coplanar line structure with GND excluding through holes may be used. . Although the coplanar waveguide has a problem that it is difficult to design, it is suitable at 10 GHz or more, and a characteristic satisfying practical use is obtained up to a frequency of 100 GHz or more.

According to the present invention, it is possible to precisely control the width and interval of the conductor wiring. Therefore, as shown below, it is possible to achieve improved characteristics and advanced package functions using conductor lines.

 (a-3) Impedance adjustment line

 For example, FIG. 5 schematically shows a plan view of a conventional structure of an ultra-high frequency ceramic package 20 applied at 10 GHz or more called Micro X. The element 21 mounted in the center is a GaAs FET bare chip with high electron mobility. Although simplified in FIG. 5, the substrate 22 on which the bare chip is mounted is a multilayer laminated substrate similar to that of FIG. 10 and the like.

 In Micro X, a conductor line that connects to the gate, drain, and source terminals. , D, and S are arranged perpendicular to each other to suppress the parasitic capacitance. These conductor lines are inner layer wiring inside the substrate and are generally connected to strip lines formed separately outside the chip mounting substrate (in the figure, they are shown as one integrated inside and outside the substrate). There is.) However, the parasitic capacitance C does not disappear even if the terminals are orthogonal to each other to form the microphone opening X structure. In addition, there is an occurrence of inductance L due to the bonding wire 23 connecting each electrode of the GaAsFET and the conductor line.

In the multilayer package technology, the uniformity of the parasitic capacitance C is poor because the shrinkage rate during firing is not uniform for each package. Since the bonding accuracy is high, the wire bonding itself can usually be formed with high uniformity.However, in the conventional laminated substrate structure, dimensional changes due to shrinkage of the inner wiring due to firing shrinkage are unavoidable. Non-uniformity (variation) also becomes a problem. When the frequency is 10 GHz or more, the frequency change of impedance due to C and L increases, and a frequency band in which an appropriate signal wave current is not applied to the semiconductor chip occurs. In Micro X, this problem is reduced by connecting to (micro) strip lines separately formed on the chip mounting substrate. As a result, the connection structure between the electrodes on the element and these conductor lines is reduced. Tend to be complicated. On the other hand, in the present invention, since there is no step of “simultaneous firing of ceramics and wiring electrodes”, the parasitic capacitance C is not only uniform in each package, but also a highly accurate stripline (or coplanar type conductor). Wave line) can be built into the package for impedance correction. Examples are shown in Figs. These have conductor lines provided on the substrate, and can correct the inductance L and the parasitic capacitance C of the bonding wire with high accuracy. In addition, by using a high dielectric constant material as the substrate material, it is possible to shorten the conductor line length compared to conventional micros, and to bring out the performance of high-performance semiconductor devices to the limit and to substantially reduce their substantial dimensions. (An example of this configuration will be described in detail in Example 2.)

(a-4) Additional circuit

 Further, according to the present invention, since the width and interval of the conductor wiring can be precisely controlled, it is possible to additionally provide a high-precision planar inductor on the substrate. Therefore, circuits having various functions can be provided on the surface by combining such a planar inductor and a capacitance element such as Z or a chip capacitance available at high precision on a substrate. An example of such a circuit is a balanced-unbalanced conversion circuit.

 Generally, when two high-frequency lines or devices are connected, they must be matched so that the impedance at the connection point is equal, but the distribution of the electromagnetic field must also be the same. For this reason, a balanced-unbalanced conversion element (balun) is required to connect a terminal (balanced input / output configuration) that is insulated from GND in high frequency and a terminal grounded to GND (unbalanced input / output configuration). .

Currently, balanced power amplifiers, low-noise amplifiers (LNAs), and mixers that are driven by low voltages to achieve a wide dynamic range and high gain are being commercialized. Equilibration of the high-frequency circuit eliminates the need for MMICs such as power switch transistors and DC / DC converters for negative voltage generation, and eliminates the need for MMICs for mobile communications. The wave circuit can be significantly reduced in size and cost. However, when the LNA is balanced in the example of the configuration of the mobile phone receiver from the antenna (ANT) to the low noise amplifier (LNA :) via the antenna switch (ANT-SW) and then to the SAW filter, the subsequent stage Either upgrade the SAW filter to a balanced type, or use a balanced converter between the LNA and the SAW filter. However, it is not easy to change the SAW filter to a balanced type. The balun can be composed of a combination of an inductor and a capacitor, as shown in the equivalent circuit of FIG. 8, and in the present invention, by mounting the circuit shown in FIG. A package can be used (an example of this configuration will be described in detail in Embodiment 3). In the present invention, an inductor electrode is formed on a fired substrate such as an alumina substrate, so that a highly accurate inductor electrode can be formed. For example, Japanese Patent Application Nos. Indak evening described in Hei 10-182045 can be used. In addition, a high-performance circuit can be constructed by using a small, large-capacity chip capacitor with a high Q value. If necessary, the characteristic impedance may be adjusted using conductor lines.

 (a-5) Composite module package

 As understood from the description of (a-4), the present invention can be applied to all circuits having high-frequency components that require hermetic sealing. For example, in a high-frequency circuit including one or more GaAs FETs, SAW filters, or MMICs, it is possible to seal each of these high-frequency elements, two or more of them, or the entire circuit as described above. Is described in detail in Example 5.) (b) Cap member

The cap member functioning as a lid may have any shape and height so as to form a space having a size sufficient to accommodate the element when brought into close contact with the surface of the substrate. Also, it is sufficient if the protective member has sufficient strength. Caps made of inorganic material, organic material, and metal can be used for sealing. Alumina, quartz glass, etc. made of inorganic material, plastic made of organic material Metals such as paints, epoxies, and the like include iohaku (Western white), phosphor bronze, and copper.

 If a metal cap is used, the high-frequency device will be surrounded by a conductive material, and almost perfect shielding can be obtained by grounding the cap to GND. Also, there is a high shielding effect without grounding.

 If a metal cap is used, it must be insulated from the conductor tracks on the substrate surface. Insulation between the metal cap and the conductor line can be achieved by providing an insulating layer between the cap and the conductor line by thick-film printing or the like. In the present invention, the sealing auxiliary layer also functions as an insulation layer.

(c) Adhesive sealing

 In the present invention, in addition to adopting the above-described substrate structure, a sealing auxiliary layer which is a cured body of the sealing auxiliary layer or an inorganic material layer is provided on a ceramic substrate having a region for mounting a high-frequency element, and a cap A major feature is that the member is bonded to the sealing auxiliary layer with an adhesive to perform sealing.

 The use of an adhesive eliminates the need for a heat treatment at several hundred degrees Celsius, which is required when sealing with solder-glass frit. Also, by activating the surface of the sealing auxiliary layer prior to bonding, highly reliable bonding and sealing that can withstand repeated thermal expansion after mounting the element module can be realized.

Heretofore, for example, in the case of a quartz oscillator or the like, a sealing method in which a cap-shaped sealing material is directly joined to the oscillator substrate has been adopted. However, in the case of crystal oscillators and the like, heat generation during mounting and use is small, and there is little possibility that the bonding interface will be degraded due to repeated thermal expansion of the package. On the other hand, the sealing method according to the present invention is used for sealing SAW filters, GaAs FETs, MMIC power amplifiers, etc., which are used in a high frequency or ultra-high frequency band, generate a large amount of heat, and have a high level of required moisture resistance. Must be adopted. The sealing auxiliary layer is formed on the substrate in a shape compatible with the end surface of the cap member. Specifically, a polymer resin is printed and cured in the area including the joint with the cap member on the substrate, or an inorganic material layer is formed by thick-film printing or other methods and then fired and sealed. An auxiliary layer.

 The organic polymer material that can be used as the sealing auxiliary layer in the present invention includes, as a main component, a resin having heat resistance, moisture resistance, and insulation properties, such as an epoxy resin, a phenol resin, and an epoxy phenol resin. It is preferable to use resin materials in which a curing agent, a reppelling agent, an antifoaming agent, an inorganic filler, and the like are dispersed in order to impart coatability such as screen printing to these materials. Examples of the leveling agent or the defoaming agent include those containing silicone oil as a main component. However, when a silicone-based leveling agent or antifoaming agent is used, the amount added should be 0.01 to 2.0 wt. % Is preferably used. It is preferable that the leveling agent is modified with epoxy. It is preferable to add the inorganic filler in consideration of the anchoring effect at the time of epoxy bonding, but in this case, use a filler with an average particle size of about 0.5 to 10 m suitable for screen printing. Is preferred.

 When the sealing auxiliary layer intersects with the wiring or the like on the substrate surface, which is printed on the substrate by a common method such as screen printing, the sealing auxiliary layer absorbs irregularities due to the conductive path on the substrate surface, and the cap member is made of metal. In some cases, in order to ensure insulation from the wiring conductors on the board, cover the surfaces of the electrodes or conductor lines, that is, make them thicker than these conductor paths, and make the resin layer surface as a whole. The height must be even. This can be realized by adjusting the viscosity to an appropriate value with the above-mentioned additives and the like. Usually, a layer having a thickness of about 10 to 50 may be used (the same applies to the case of an inorganic material described later).

After printing, the organic polymer layer is cured to form a sealing auxiliary layer. In the present invention, the inorganic material that can be used as the sealing auxiliary layer is not particularly limited, and various inorganic glasses and oxides can be used. Among them, crystallized silica glass is preferred.

The crystallized silica glass, S i 0 ₂ - M G_〇 one Z n O- A l ₂ 〇 ₃ system, P b O-Z N_〇 one B ₂ 〇 ₃ - S i 0 _2, and the like, As will be understood from the following description, glass other than this may be a glass that precipitates microcrystals during sintering and does not contain lead. Crystallized silica glass may have pinholes of about several meters, but no problem occurs if the thickness is about 10 to 20 m.

 The reason why the packaging performance (moisture resistance, etc.) of the device can be improved by using crystallized silica glass is unknown, but one of the reasons is that microcrystal grains precipitate on the surface during sintering. Therefore, it is conceivable that the surface roughness increases and the anchoring effect of the adhesive increases.

 If the wiring conductor connecting the internal electrode and the external electrode is formed on the surface of the substrate, or if the cap member needs to be made of metal to ensure insulation from the wiring conductor on the substrate, the sealing auxiliary layer Will overlap with part of the wiring conductor, but the plating layer formed by electroless plating, especially the Au plating layer surface, is chemically inert, and the adhesion between the conductor layer and the sealing auxiliary layer is reduced. I do. Therefore, it is necessary to form a sealing auxiliary layer before plating. However, when the glass component contains lead, the lead component elutes into the plating solution during the Au plating, and becomes a catalyst poison. In crystallized silica glass, such a situation does not occur, and it is considered that Au plating progresses smoothly and contributes to the improvement of characteristics.

 Preferably, after performing the surface activation treatment on the sealing auxiliary layer, the sealing auxiliary layer is bonded to the cap member. The surface activation treatment of the sealing auxiliary layer includes various chemical or physical treatments for increasing the affinity with the adhesive. Among them, ultraviolet treatment and plasma treatment are preferred.

The ultraviolet treatment is performed by irradiating the surface of the sealing auxiliary layer with ultraviolet light. UV irradiation The chemical affinity of the sealing auxiliary layer for the adhesive increases, and a high degree of hermetic sealing can be realized. Irradiation energy depends on the type of the sealing auxiliary layer and the like, but in the case of a polymer resin material, it may be generally within a range of 400 to 160 mJ. In general, if it exceeds 160 OmJ, the adhesive strength is rather lowered. In addition, the oxidation of the conductor thick film proceeds easily. On the other hand, a remarkable effect is not obtained below 40 OmJ. Usually, the range of 400 to 100 OmJ is preferable. The wavelength of the irradiation ultraviolet rays is selected so as to include a wavelength range in which active points are formed in the cured polymer resin layer. In the case of an inorganic material layer, it is preferable that the energy irradiation amount is larger as long as it does not adversely affect the conductor layer and the like on the substrate surface.

 Such ultraviolet irradiation can be performed using, for example, a low-pressure mercury lamp. Plasma treatment is also preferable as the surface activation treatment of the sealing auxiliary layer in the present invention.

 The plasma treatment is performed by applying a high-frequency AC voltage between electrodes filled with decompressed gas to generate a glow discharge between the electrodes and bringing the plasma of the gas component into contact with the substrate. The plasma treatment removes the contaminant layer and promotes surface roughening and formation of Z or chemically active sites. Specifically, the substrate on which the above-mentioned sealing auxiliary layer is formed is placed in a plasma processing apparatus capable of reducing pressure, and the atmosphere in the apparatus is appropriately replaced with a plasma processing gas. Perform by applying. The gas used for the plasma treatment is not particularly limited as long as it is non-oxidizing gas. Examples of such a gas include an inert gas such as helium, neon, and argon, and nitrogen. Argon is preferred. The pressure of the processing gas is 1 mTorr to 1 O Torr, preferably 1 O mTorr to: L Torr, and more preferably about 100 to 300 mTorr.

The high-frequency power supply may have a frequency in the range of 1 to 100 MHz and a power of about 10 to 300 W. When the sealing auxiliary layer is a polymer material, it is preferably about 50 to 200 W, and when it is an inorganic material, it is preferably about 200 to 300 W. The processing time depends on the type of the sealing auxiliary layer, but is usually in the range of 10 to 300 seconds. When an inorganic material is used, 3 to 5 minutes is preferable. If the processing time is too short, the effect of the processing will not be sufficiently exhibited. If the treatment time is too long, the etching effect of the plasma is exerted on the electrode and the conductor layer on the substrate surface, which is not preferable.

 The adhesive is not limited as long as it has good adhesiveness to the above-mentioned cured surface and excellent airtightness. Examples of such an adhesive include an epoxy-based adhesive and an epoxy-phenol-based adhesive.

 in Mac

 The high-frequency device of the present invention can be manufactured by a method schematically shown in FIG.

 Specific operations and the like in each step are as described above.

 Further, the present invention further provides a manufacturing method using a collective substrate. A step of forming a plurality of package substrate regions by providing vertical and horizontal dividing lines including a through hole on a ceramic substrate; a step of forming a conductor path for conducting the front and back surfaces of the substrate through the through hole; Forming an internal electrode for mounting the element and a conductor line connecting the internal electrode and the conductor path in the through-hole on the surface on the side where the element is mounted in the region; opposite to the surface on which the element is mounted in each substrate region Forming external electrodes electrically connected to the conductor paths in the through-holes on the side surface; forming a space large enough to accommodate the element when closely contacting the substrate surface in each substrate region Forming a cap member having a desired shape and height; in each substrate region, at least between the internal electrode and the edge of the substrate region; A compatible shape with the end face, or cured printing the organic polymer material layer, which comprises steps of providing an inorganic material layer; in parallel beauty, comprising the step of dividing along the substrate to the dividing line.

In short, this is to form a number of package substrate areas on a single substrate and cut out individual substrate pieces from this collective substrate. An overview This is schematically shown in FIGS.

 In the embodiments shown in these drawings, perforations (through holes) 72 are formed at predetermined positions of the inorganic insulator substrate 71 (FIG. 11 (a)). The formation of through-holes is possible in any way. For example, drilling with a single laser beam, drilling with a drill, and the like can be given. It may be fired after punching on a ceramic green sheet.

 Then, a conductor is printed, filled and Z or plated in the through hole 72 to form electrodes and conductor lines 73 on the surface of the substrate and electrode terminals on the back surface (not shown) of the substrate (FIG. 11). (B)). The formation of the electrodes and the like is similar to the case where the individual substrate is used. Also, for example, when a coplanar line is used, the side conductor layer is formed, when a distributed constant type is used, a GND layer on the back side is formed, or when an additional circuit is mounted, an inductor pattern is also formed. Good.

 After forming the electrodes and the like, a sealing auxiliary layer 74 is formed as in the case of the individual substrate (FIG. 12 (a)), and the surface is activated (FIG. 12 (b)).

 Thereafter, the module is separated into individual modules packaged on the substrate surface. Separation into individual chips can be performed, for example, by a conventional method such as sawing, but by forming a shallow dividing line on the substrate and applying a deformation force along the dividing line after resin sealing. The substrate may be divided. It is preferable to divide the through hole along the through hole, and the divided through hole can be used as a conductive portion to the back surface or a side electrode.

 In the above description, various modifications and changes, such as using a collective substrate without through holes, rearranging the order of the steps, and replacing operations in each step with conventional equivalent operations, are also described in the present description. Included in the scope of the invention.

The manufacturing method of the present invention further provides a method for further improving the efficiency of the entire package manufacturing process by inspecting the semiconductor device after being formed as a collective substrate and before dividing it into individual pieces (this method is described in the next section). Packaging method This will be described in detail in the description of the method. ).

Packaging method for high frequency devices

 A packaging method for a high-frequency device according to the present invention can be realized using the above-described package.

 That is, as schematically shown in FIG. 3, an electronic component is mounted on a ceramic substrate having a sealing auxiliary layer, and the electronic component is sealed by bonding a cap member. The package structure is as described above.

 Examples of the mounting method include a resin bonding method using a conductive paste or a bonding method using brazing or the like. After bonding, for example, flux cleaning is performed using an alternative chlorofluorocarbon (HFCFC), and electrical bonding between the electronic component and the thick film substrate is performed by wire bonding or the like. In consideration of the inductance caused by the bonding wire, it is preferable that the wire length is as short as possible and the wire thickness is large. Usually, a gold wire having a diameter of 10 to 50; m, preferably 15 to 30 / m is used.

 The environmental conditions (especially humidity) during the sealing process are important. For example, air dehumidified by activated alumina etc. with a dew point of 140 ° C or less is blown, and the dew point of the working area is 120 ° C or less. The sealing operation is carried out under the condition maintained at. The adhesive strength of the ceramic lid of the sample prepared in this way is higher than that of the sample with a low melting point glass that is generally used for conventional oscillators, etc. Will be much stronger.

Further, according to the present invention, there is provided a method of packaging an element using a collective substrate, that is, a step of forming a plurality of package substrate regions by vertically and horizontally providing dividing lines including through holes on a ceramic substrate; Step of forming a conductive path for conducting the front and back surfaces of the substrate through the through hole: connecting the internal electrode for mounting the element and the internal electrode to the conductive path inside the through hole on the surface on the element mounting side in each substrate area. Forming conductor lines; forming elements in each substrate area Forming an external electrode on the surface opposite to the mounting side to be electrically connected to the conductor path in the through-hole; in each of the substrate regions, a large enough to accommodate the element when brought into close contact with the substrate surface; Preparing a cap member having a shape and a height for forming a space of a height; in each substrate region, at least between the internal electrode and the substrate region 緣, a shape adapted to the end face of the cap member; A step of printing and curing a polymer material layer or providing an inorganic material layer as a sealing auxiliary layer: in each substrate region, after mounting a high-frequency element and electrically connecting to the internal electrode, the cap A method for packaging a high-frequency element, comprising: bonding a member onto the sealing auxiliary layer with an adhesive to hermetically seal; and dividing the substrate along the dividing line. It is.

 Here, the procedure up to the mounting of the element is the same as that described with reference to FIGS. 11 and 12. Thereafter, the element is mounted and the connection is performed by wire bonding (FIG. 13 (a)). After wire bonding, the substrate surface is sealed with a cap member 77, and then separated into individual packaged modules (FIG. 13 (c)). For separation into individual chips, the substrate may be divided by forming a shallow dividing line on the substrate and applying a deforming force along the dividing line after resin sealing. By dividing along the through hole 72, the inner surface of the through hole 72 can be used as a conductive portion to the back surface or a side electrode 79.

 In this method, the aggregate substrate is divided in a state where the edge of each substrate region is structurally reinforced by bonding the cap member, so that the stress at the time of division tends to concentrate on the division line, and the division of each substrate region is performed. Can be realized more reliably.

 Further, according to the manufacturing method or the packaging method of the present invention, it is possible to realize an efficient method for inspecting a high-frequency package or a packaged module.

This is done by using a wafer probe as an inspection means for a package or an assembly of packaged modules. Wafer probers are widely used for precision measurement, intermediate inspection, and shipping inspection of semiconductor products, and include a test head, a probe card, and a stage that can be moved in the XY and vertical directions. The probe card is a replaceable part that is attached to the test head and includes a plurality of wires and a plurality of probe pins electrically connected to the wires. In the inspection of a semiconductor wafer by a wafer prober, the semiconductor wafer before being diced is placed on a stage, and the probe pins are brought into contact with the electrodes of the semiconductor products collectively formed on the wafer, so that a current flowing between the electrodes is obtained. Is measured, and defective products are identified by inspection of electrical characteristics.

 Although the inspection method of the present invention is known as an inspection apparatus for a semiconductor wafer, a wafer probe which has not been used for inspection of a high-frequency package and / or a packaged high-frequency element has been disclosed. It is characterized in that it is used for inspection. Specifically, the above-mentioned collective substrate is placed on the stage of a wafer probe with the element mounting area side down, and probe pins are brought into contact with the electrodes on the back surface of the substrate to inspect individual high-frequency elements. . Before mounting the device, various inspections can be performed on the front side of the board.

 As a specific inspection method, a semiconductor wafer inspection method using a wafer prober can be used almost as it is. For example, even when the input / output electrode position of the high-frequency package is changed according to the desired electrical characteristics, it may be performed by exchanging the probe card / probe pin and changing the control program. Therefore, it is possible to inspect various products at low cost. Wafer prober inspection processing capacity does not exceed 1 second per product area even in precision measurement. Multiple high-frequency devices (or packages) may be inspected simultaneously by applying a multi-prober. In this case, the inspection time per product area is reduced to 1/2 to 1/3 second.

As described above, conventional multilayer high-frequency devices (or packages) require the production of special jigs corresponding to individual modules for inspection due to their structure. Force According to the method of the present invention, a collective substrate is used in place of a wafer in a wafer prober, so that a dedicated jig for an individual module is not required. Furthermore, since the wafer probe has a movable stage, there is no need for the large-sized transfer equipment used in the conventional automatic inspection of high-frequency devices (or packages), and the probe can be used semi-permanently. .

 Furthermore, in the wafer probe, the calibration up to the probe tip can be performed by using the calibration substrate. As a result, the intrinsic characteristics of the product can be accurately measured. It is also easy to inspect temperature characteristics. Quality assurance regarding temperature characteristics has always been a major problem with ceramic electronic components. Major changes, such as maintenance, were necessary and were not realistic. However, in general, a wafer prober is a small device that can be carried around and can be calibrated at the probe level such as S-LT (Short-Open-Load-Through) calibration. Precise measurement can be easily performed.

 The high-frequency element package of the present invention can be applied to a wide range of high-frequency elements of several tens of MHz to 100 GHz. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the present invention will be described more specifically with reference to examples.

 Example 1

 (1) Improvement of adhesion by UV treatment

Electrodes and conductive lines are formed on a 0.64 mm thick 5 mm square 96 alumina substrate by thick film printing using a thick film conductor paste of Ag-Pd alloy (Fig. 3 (b)). In addition, silicone oil (content 0.6 wt) as leveling agent, silica fine powder with an average particle size of 5 zm as inorganic filler, and epoxy as hardener A phenolic resin agent (BPA (bisphenol A) resole type phenolic resin) containing a xy adduct was printed on the surface of the substrate along a part of the surface (Fig. 3 (c)). After curing, a synthetic quartz glass mercury lamp (manufactured by Nippon Battery) was irradiated while measuring the irradiation energy with an integrating photometer (Fig. 3 (d)). After mounting the SAW film on the substrate manufactured in this way, bonding was performed using Au wires to electrically connect the element to the thick film substrate (Fig. 3 (e)).

 On the other hand, an adhesive containing bisphenol A-type epoxy resin as the main component is adjusted in advance, and the surface tension of the adhesive before bonding is equal to the surface tension of the resin on the surface to be bonded. Epoxy adduct (curing agent), inorganic fine particles, and varnish are added and ripened so that the state can be realized, and the coating is applied to the surface to be bonded. Alumina ceramic with a thickness (wall thickness) of 0.5 mm in dry air Sealing was performed by bonding a cap made of glass (Fig. 3 (Π)).

 The above package was kept in an environment of 12 It :, 2 atm, and 100% humidity in an environmental tester, and the characteristic degradation was evaluated using the transmission characteristics (201 ogMagl SI) as an index. In addition, the same test was performed on a SAW filter module manufactured in the same manner as above except that the organic polymer cured layer was not provided.

 As a result, the SAW filter module of the present invention maintained almost the initial characteristics even after the elapse of 50 hours, indicating that the SAW filter module of the present invention has excellent airtightness. Further, in the comparative test example, remarkable deterioration of characteristics was observed after 50 hours, and it was confirmed that the effect of the present invention was at a level that could not be realized by mere sealing with an adhesive.

 (2) Improvement of adhesion by plasma treatment

 (a) Preliminary experiment

A silica glass paste (same as the sample A in (b) below) was printed on a 96-alumina substrate so as to have a thickness of 15 m, and was fired at 850 ° C. When the surface after firing was observed with an electron microscope, it was confirmed that fine crystals had precipitated. Was done. This is considered to be aluminobarium silicate-based microcrystals. A water drop was dropped on the surface of the crystallized silica glass using a contact angle goniometer, and the contact angle was measured. The result was 8 to 15 °. The contact angle was 70-80 ° on a 96-alumina substrate with a clean surface without a crystallized silica glass coating layer, confirming that the application of the crystallized silica glass layer was useful for improving wettability.

(b) Plasma treatment

 Electrodes and conductor lines are formed on a 0.64 mm thick 5 mm square 96 alumina substrate using an Ag-Pd alloy thick conductor paste (Fig. 3 (b)), and an inorganic glass material is further applied to the substrate surface. It was printed along its edge (Fig. 3 (c)). The same sample as above except that no inorganic glass layer was provided was prepared as a control.

After firing the inorganic material in at 8 50, after placing the substrate on the high-frequency power supply side of the plasma processing apparatus (MARCH Co. PX-1 000), it was reduced to 1 0- ² Torr, introducing A r gas, The inside of the processing chamber was adjusted to 18 OmTorr. Thereafter, plasma was generated under the condition of an output of 250 W and the treatment was performed for 240 seconds. In this treatment, the sample surface is negatively charged by the electrons in the plasma, while the excited argon gas becomes positive ions and accelerates and collides with the sample surface. As a result, activation of the substrate surface is realized.

 After mounting the SAW film on the substrate manufactured in this way, bonding with an Au wire is performed to electrically connect the element and the thick film substrate. Sealing was performed by bonding the cap (Fig. 3 (e) (f)).

And evaluate the characteristics deterioration of | (S _{2 l} I 201ogMag) as an index, 2 atm, holding transmission characteristic in 100% humidity environments: the package in the environmental test chambers 1 2 I. With crystallized silica glass layer, with lead borate glass layer The following table shows the results of tests performed on 10 samples each of which were given.

 table 1

 As shown in the above results, it was confirmed that when a sealing auxiliary layer made of an inorganic material was provided according to the present invention and this was subjected to plasma treatment and used, an extremely excellent result was obtained as a sealing package for a high-frequency device. . When a crystallized silica glass layer was used as the sealing auxiliary layer, an excellent sealing effect was maintained even after more than 10 hours.

Example 2

 6 and 7 show examples of the structure of the ceramic package for GaAs FET. FIG. 6 shows a microphone opening X structure constructed according to the present invention, wherein (a) is a plan view and (b) is a side view as viewed from the direction A in (a).

The microphone opening X structure package of the present invention shown in FIG. 6 has a conductor line G on a ceramic substrate 32 having a substantially rectangular element mounting area (a state where a GaAs FET bare chip 31 is mounted in the figure) in the center. , D, and S are formed at right angles from the region, and a sealing auxiliary layer 33 is provided circumferentially. The sealing auxiliary layer 33 has a thickness sufficient to cover the conductor line at the intersection with the conductor line. After the formation of the sealing auxiliary layer 33 (cured for an organic polymer material and fired for an inorganic material; the same applies hereinafter), the capping member 35 is sealed via an adhesive layer 34. As a substrate material, a 96-alumina thick-film printed circuit board is excellent in cost performance, but as a substrate material, 99.3% purity alumina substrate or 99.99% aluminum substrate is used. Mina substrates can also be used. The parasitic capacitance is suppressed by making G, D, and S orthogonal.

 The conductor lines G, D, and S are planar lines formed on the substrate after firing, and are directly connected to the bare chip by wire bonding or the like. The conductor line may be formed by thick-film printing as in the first embodiment, but a high-precision thin-film electrode can also be used for high-performance requirements and ultrahigh-frequency applications.

 In the structure shown in FIG. 6, the input / output terminals are the side electrodes 36, but FIG. 7 shows a configuration example in which the conductor lines are the strip lines or coplanar lines shown in FIG.

 That is, in the GaAsFET ceramic package, the conductor lines G, D, and S are formed on a ceramic substrate 42 having a substantially rectangular element mounting area (a state in which a GaAsFET bare chip 41 is mounted in the figure) in the center. Each substrate has a substrate structure formed at right angles from the region and provided with a sealing auxiliary layer 43 in a circumferential shape. The sealing auxiliary layer 43 has a sufficient thickness to cover the conductor line at the intersection with the conductor line. After the formation of the sealing auxiliary layer 43, the sealing is performed by the cap member 45 via the adhesive layer 44. The back surface of the substrate has a conductor layer 46 that covers substantially the entire surface. The conductor layer 46 may be formed by thick film printing or by bonding a metal foil.

 In the package structure shown in FIG. 7, S is connected to the GND layer 46 on the back surface through a through hole.

 In the embodiment of FIG. 7, the conductor lines G and D are arranged in a straight line, as in FIG. 6, so that the effect of suppressing the parasitic capacitance is high.In addition, the degree of freedom in selecting the distributed constant lines is high and the frequency is increased. It has features that it is easy, it can suppress electrode loss and parasitic capacitance by using G and D distributed constant lines, and S can be grounded immediately to GND by through holes, so that GND impedance can be suppressed.

Well 3 Fig. 9 shows an example of the configuration of a SAW filter package 50 incorporating a balanced-unbalanced conversion circuit. The point that the conductor line was provided on the substrate 52 on which the element 51 was mounted was the same as in Examples 1 and 2, but in this example, by further mounting the inductor and chip capacitor, The built-in balance-unbalance conversion circuit shown.

 With the conventional lamination technology, the shrinkage rate during firing is not constant, so it is impossible to adjust the inductance and capacity with high accuracy, and it is not possible to control the capacity fluctuation to ± 10% or less. However, according to the production method of the present invention,

 ① High-precision ink can be formed by thick film printing.

 ② The capacity accuracy of discrete capacity is as high as 1.5% on soil.

Therefore, there is almost no change in the center frequency.

 As a method for forming the inductor pattern, any conventional method can be used. For example, the conductive material can be formed by printing a thick film or a thin film, or by placing a thin wire in a coil shape. In thick-film printing, a coil having a diameter of about 0.5 to 10 mm can usually be formed with a line width of about 60 to 300. In thin film formation, a coil having a line width of about 1 to 100 and a diameter of about 0.1 to 2 mm can be formed.

 In this example, a rectangular spiral inductor (square-shaped inductor) is used, but the shape can be changed according to the purpose as long as it can be arranged on the substrate surface. Such inductors include various inductor patterns composed of a crank or a loop or a conductor path forming a part thereof, in addition to the spiral inductors. More than H, usually about 1 to 50 nH is used.

In the configuration example shown in Fig. 9, the rectangular inductor has a conductor width of the inductor pattern and a space between conductor lines of 100 im, and is balanced by using an inductor having the following inductance value and a chip capacity. Converter (center frequency 8 5 o

0MHz). Inductance capacitance Characteristic impedance Configuration example 1 5.62 nH 6.24 pF 30 Ω

 Configuration example 2 9.36 ηΗ 3.75 pF 50 Ω

 Configuration example 3 14.42 ηΗ 2.43 p F 77 Ω

 In FIG. 9, the balanced converter is arranged only at the output terminal, but can be arranged also at the input terminal side. Although the sealing structure is not shown in FIG. 9, the outline is the same as in Examples 1 and 2. However, the inductor electrode and chip capacity need not be included in the hermetic seal unless they are directly connected to the SAW fill chip by wire bonding. For example, only the SAW filter is hermetically sealed according to the first embodiment, and the conversion balance circuit is arranged on one of the front and back surfaces of the package substrate. May be connected.

 Example 4

 As shown in Figs. 11 to 13, the surface of a 96-alumina substrate 71 (95 mm x 95 mm mx 0.64 mm) contains 90 individual substrate areas with an area of 5 mm wide and 5 mm long per area As described above, a divided region was provided in the center of the substrate, and a through hole 72 was formed on the divided line.

 Next, a conductive paste was filled and printed on the side surfaces of the through holes, and conductive patterns 73 were printed on the front and back surfaces of each individual substrate region.

Thereafter, the circuit pattern is fired, and in each individual substrate area, a sealing auxiliary layer 74 is printed circumferentially between the element mounting area and the edge of the substrate area, and this is cured or fired to activate the surface. (The sealing auxiliary layer after the treatment is indicated by 75.) Next, in 5, the SAW filter chip 76 was mounted in the center of the element mounting area, and wire bonding was performed. All of these operations are the same as in Example 1. Board table After wire bonding was completed in all the individual regions on the surface, a cap member 77 was adhered to the surface of the substrate and sealed to form a package structure 78. These operations are the same as in the first embodiment.

 The above-mentioned collective substrate was placed on the stage of a commercially available wafer prober with its back surface facing upward, and the characteristics of each high-frequency element were inspected according to a previously programmed procedure. The wafer probe was subjected to SOLT calibration in advance using a calibration substrate, and measurement was performed at 20 ° C.

 After the inspection of the entire area was completed, the substrate was removed from the stage, and a total of 90 individual modules packaged with high-frequency devices were obtained by applying force along the dividing line. In addition, the time required for the inspection was 90 seconds in total, which was significantly shorter than the case of inspecting the same number of individual high-frequency elements by the conventional method.

Example 5

 In a 10 GHz band oscillator with a dielectric resonator and a low-noise GaAsFET chip and passive element (TE-type dielectric resonator) mounted on a 0.64 mm-thick alumina substrate, a GaAsFET chip and a dielectric resonator were used. The entire circuit is hermetically sealed with a metal cap. The conductor lines between the elements are formed as high-precision thin-film electrodes by the photoresist method.

Oscillators applied at 10 GHz or higher obtain oscillation characteristics by tuning the GaAs semiconductor for oscillation with a TE-type dielectric resonator (DRO). At about 10 GHz, the DR〇 dimension is large compared to the micro X-package dimensions, and the DRO's resonant electromagnetic field is not disturbed. However, as the frequency increases, the DRO dimensions decrease, and the resonant fields become disturbed by the micro X-package. Also, the resonance of the package itself adversely affects the oscillation characteristics. Therefore, in higher frequency bands, it is necessary to mount GaAs semiconductors on a pair chip. However, since the DRO needs to be installed in an appropriately sized metal housing for resonance, it has conventionally been difficult to mount a GaAs semiconductor for oscillation on a pair chip. A mechanical seal (airtight metal case) had to be applied (Fig. 14 (a)). However, if the technology of the present invention is applied, an oscillator of 10 GHz or more can be produced only by bonding a metal cap (FIG. 14 (b)). Industrial applicability

 In a conventional stacked package, simultaneous firing of the package structure material and the conductor material is indispensable, and in this case, variations in conductor dimensions due to shrinkage of the firing are inevitable. Also, the method of forming the electrodes and the conductor lines is substantially limited to thick film printing. On the other hand, in the present invention, since the fired ceramic substrate is used, the problem of electrode precision deterioration due to firing shrinkage is solved, and electrode formation by thin film formation is also possible. Electrodes (conductor lines) can be built into the package structure. The realization of such a highly accurate electrode pattern substantially eliminates the variation in the parasitic capacitance of each package and enables fine adjustment of the impedance by the conductor line. Therefore, by using the package of the present invention, it is possible to manufacture a small, low-cost, high-reliability, high-characteristic high-frequency device.

In addition, the use of high-frequency equipment in the private sector is increasing, for example, in-vehicle radars using the millimeter-wave band are being put into practical use.However, in the past, high-cost technologies for products in this band have been used without hesitation. The truth is. However, according to the present invention, a high-performance millimeter-wave band module can be realized at a low cost, for example, by using an inexpensive sealing member or by performing impedance correction using a strip line with technical accumulation. . The development of new technologies requires a large amount of development costs, and in the advanced technology field, reducing development costs is directly linked to lower product prices. Thus, the sealing technology of the present invention It does not require new technologies such as thick-film coplanar waveguides, which are being tried in band modules, and can achieve improved characteristics by applying stripline technology with accumulated technology to the millimeter-wave band. module To achieve both low price and high performance.

 Furthermore, according to the method of the present invention, since a high-frequency element package or a packaged high-frequency module can be manufactured and inspected as a collective substrate, the handling property is greatly improved, and the inspection is speeded up. But it has tremendous utility.

Claims

The scope of the claims

1. (a) A ceramic substrate having a high-frequency element mounting area, and (b) a cap having a shape and height that forms a space large enough to accommodate the element when brought into close contact with the surface of the substrate. A high-frequency element package including a member, wherein the ceramic substrate is formed after sintering of a substrate material, an internal electrode for mounting the element, an external electrode, and a conductor line connecting between the electrodes, and an element mounting area and the substrate. A sealing auxiliary layer made of a cured product of an organic polymer material or an inorganic material provided in a shape compatible with the end face of the cap member between the 緣 portion and a device mounted on the region, and After the electrical connection, the cap member is bonded to the sealing auxiliary layer with an adhesive to hermetically seal the package.

 2. The package for a high-frequency device according to claim 1, wherein the surface of the sealing auxiliary layer is activated by ultraviolet irradiation or plasma treatment.

 3. The high-frequency element package according to claim 1, wherein the organic polymer material includes a resin selected from an epoxy resin, a phenol resin, and an epoxy phenol resin.

 4. The high frequency element package according to claim 1, wherein the inorganic material is crystallized silica glass.

 5. The high-frequency device package according to claim 1, wherein the impedance of the packaged device is optimized by the conductor line.

 6. The high-frequency element package according to claim 1, wherein the conductor line includes a high-precision distributed constant line formed by forming a thin film.

7. The high-frequency element package according to claim 1, wherein the conductor line includes a coplanar line.

8. The package for a high-frequency device according to claim 1, wherein the ceramic substrate is selected from alumina or a dielectric material having a higher dielectric constant than alumina.

 9. The high frequency element package according to claim 1, wherein the cap member is selected from a ceramic, a metal, or a polymer material.

 10. The high-frequency element package according to claim 1, wherein a circuit including a spiral inductor and / or a chip capacitor is provided on the surface of the substrate.

11. The high-frequency element package according to claim 1, wherein the element is a SAW filter, a MIC, an MMIC, or a GaAs FET.

 12. The SAW filter package according to claim 11, wherein the element is a SAW filter, and the circuit has a balanced-unbalanced conversion circuit on a substrate.

 13 3. The device is a GaAs FET, and the conductor lines connected to the gate (G) and drain (D) are on a straight line, and the distributed constant line connected to the source (S) is orthogonal to this. The GaAsFET package according to claim 11, wherein the GaAsFET package is provided on the substrate.

 14. A plurality of element mounting areas connected by a conductor line on a substrate, and the whole including these elements or one or more of these elements that need to be hermetically sealed by the cap member are claimed. A high-frequency module package sealed by the package structure according to item 1.

15. The step of forming the internal electrodes for mounting the elements, the external electrodes, and the conductor lines connecting between them on the fired ceramic substrate; large enough to accommodate the elements when brought into close contact with the surface of the substrate Forming a cap member having a shape and a height to form a space for the organic polymer material; and forming a cap member at least between the internal electrode and the edge of the substrate so as to conform to the end face of the cap member. A method for manufacturing a high-frequency element package according to any one of claims 1 to 14, comprising a step of printing and curing a layer or providing an inorganic material layer. Law.

 16. The method for manufacturing a package for a high-frequency element according to claim 15, further comprising a step of activating the surface of the cured organic polymer material layer or the inorganic material layer by ultraviolet irradiation or plasma treatment.

 17. A step of forming a plurality of package substrate regions by vertically and horizontally providing dividing lines including a through hole on a ceramic substrate; a step of forming a conductive path for conducting the front and back surfaces of the substrate through the through hole; Forming an internal electrode for mounting an element and a conductor line connecting the internal electrode and the internal conductor path in the through hole on the surface on the side where the element is mounted in the region; the side opposite to the surface on which the element is mounted in each substrate region Forming an external electrode electrically connected to the conductor path in the through hole on the surface of the substrate; a shape that forms a space large enough to accommodate the element when it is brought into close contact with the substrate surface in each substrate region And forming a cap member having a height; and in each substrate region, at least an end surface of the cap member between the internal electrode and the substrate region 緣. A step of printing and curing an organic polymer material layer or providing an inorganic material layer in a suitable shape; and a step of dividing the substrate along the dividing line, the substrate region and the cap member. 16. A method for manufacturing a package for a high-frequency element, wherein the package is a package substrate and a cap member according to any one of claims 1 to 15.

 18. The high frequency element package according to claim 17, further comprising a step of activating the surface of the cured organic polymer material layer or the inorganic material layer by ultraviolet irradiation or plasma treatment prior to the bonding step. Production method.

 19. The method for manufacturing a high-frequency device package according to claim 17, further comprising a step of inspecting electrical characteristics of each substrate region before said division.

20. The inspection is performed using a semiconductor probe inspection prober. Item 10. The method for manufacturing a high-frequency element package according to Item 19.

21. Step of forming a plurality of package substrate regions by providing vertical and horizontal dividing lines including through holes on a ceramic substrate; forming conductor paths that conduct the front and back surfaces of the substrate through the through holes; Forming an internal electrode for mounting an element and a conductor line connecting the internal electrode and the internal conductor path in the through-hole on the surface on the side where the element is mounted in the region; the side opposite to the side where the element is mounted in each substrate region Forming external electrodes that are electrically connected to the conductor paths in the through-holes on the surface of the substrate; a shape that forms a space large enough to accommodate the element when it is brought into close contact with the substrate surface in each substrate region And providing a cap member having a height; and in each substrate region, at least an end surface of the cap member between the internal electrode and an edge of the substrate region. A step of printing and curing an organic polymer material layer to a suitable shape or providing an inorganic material layer as a sealing auxiliary layer; in each substrate region, a high-frequency element is mounted and electrically connected to the internal electrode. After the connection, a step of bonding the cap member to the sealing auxiliary layer with an adhesive to hermetically seal; and a step of dividing the substrate along the dividing line. Packaging method.

 22. The high frequency element package according to claim 21, further comprising a step of activating the surface of the cured organic polymer material layer or the inorganic material layer by ultraviolet irradiation or plasma treatment prior to the bonding step. Method.

 23. The packaging method for a high-frequency device according to claim 21 or 22, further comprising a step of inspecting electrical characteristics of each substrate region at any stage before the division. .

 24. The packaging method for a high-frequency device according to claim 23, wherein the inspection is performed using a semiconductor probe A prober.