RU2351037C1 - Case for microwave semiconductor device and method of its manufacture - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to electronics. In the case for the microwave semiconductor device, in which the heat removing base and frame is made monolithically, the latter is in the form of a welt on its perimeter with a thickness of not more than 2.0 mm, ceramic-metal input-output are also made monolithically in the form of a conductor from metal or metallic alloys, which have low electrical resistance, located inside a pipe with an internal cross-section of 0.2-1.0 mm, made from precalcined ceramics, ceramic-metal input-output and correspondingly a through-hole for them in the frame is made with a round cross-section, the size of the section is the length of the ceramic-metal input-output, and also the size of the section of their conductors and the size of their contact areas is determined by set-up parameters semiconductor device, and the contact areas are made on the ends of the ceramic-metal input-output parallel and/or perpendicular to their axes. Also presented is a method of making the case for the microwave semiconductor device.

EFFECT: increase in the reliability and durability, increase in the microwave power output, increase in the technological efficiency and lowering labour input during manufacture, reduction of mass-size characteristics.

7 cl, 1 dwg

Description

The invention relates to electronic equipment, namely to ceramic-metal cases for microwave semiconductor devices.

One of the main functions of the housing for a microwave semiconductor device is to provide:

firstly, tightness and reliability, and, first of all, from the point of view of protection from environmental influences, adversely affecting the parameters of a microwave semiconductor device,

secondly, effective heat removal from the semiconductor microwave device and, above all, with the aim of obtaining the maximum allowable microwave output power,

thirdly, the durability of the microwave semiconductor device, and especially when operating in the mode of high microwave power levels,

fourthly, the minimum weight and size characteristics.

In addition, it is equally important to ensure the possibility of reliable planar connection of the housing with other elements of devices and systems of microwave electronics.

Known housing for a powerful hybrid integrated circuit and method of its manufacture, which are:

- heat sink base and frame for inputs / outputs made of oxygen-free hard copper;

- a ceramic-metal input / output of a prefabricated design made in the form of a ceramic sleeve locally metallized for soldering both in the area of its connection with the frame and with the pin type conductor. In this case, the conductor is made composite in the form of a copper core and an alloy of the Kovar type and connected to a metallized ceramic sleeve by high-temperature soldering at temperatures above 780 ° C;

- a cover made of an alloy such as Kovar or another alloy [1, p. 7/4].

The presence in the design of the casing of a technological pair of materials in the form of oxygen-free hard copper and an alloy of the Kovar type

firstly, it makes this design tense due to a significant difference in the values of thermal coefficients of linear expansion of materials and, therefore, the housing as a whole is not reliable enough, and especially when working in the mode of high microwave power levels;

secondly, it leads to significant microwave losses, which complicates the use of this housing for microwave semiconductor devices;

Known housing for integrated circuits of high-speed connected electronic equipment and a method for its manufacture, which are

- heat sink with forced cooling, made of a pseudo-alloy based on oxygen-free copper and tungsten or molybdenum;

- a frame with through holes for inputs / outputs located on one of the surfaces of the heat sink base around its perimeter;

- located on said surface of the base, at least one metal contact pad for the location and subsequent connection with it of a crystal or crystals of an integrated circuit;

- at least two metal-ceramic inlets / outs of aluminosilicate ceramics, wherein the conductor is made of molybdenum or tungsten, some contact pads of which extend onto the said surface of the heat-removing base, and others through the through holes in the frame,

In the process of manufacturing cermet inputs / outputs, conductors are applied onto unfired aluminosilicate ceramics by the method of thin-film metallization from molybdenum or tungsten, followed by high-temperature firing in a redox environment;

- while the ceramic-metal inputs / outputs are connected to the frame by brazing;

- while the metal-ceramic inlets / outlets and through holes for them in the frame are made in a rectangular shape - prototype [1, p. 7/2].

The use of other materials in this housing design made it possible to slightly reduce microwave losses.

However, this case also does not provide sufficient reliability and durability, and especially when operating in the regime of high microwave power levels, and microwave output power.

The technical result of the proposed inventions is to increase reliability and durability, and especially when operating in the mode of high microwave power levels, increase microwave output power, increase manufacturability and reduce the complexity of manufacturing, reduce overall dimensions.

The specified technical result is achieved as follows.

The proposed device is a housing for a microwave semiconductor device containing a heat sink base, a frame with through holes for ceramic-metal inputs / outputs located on one of the surfaces of the heat sink base along its perimeter, at least one metal contact pad for the location and subsequent connection of the crystal with it or crystals of a semiconductor device located on said surface of the heat sink base, at least two ceramic-metal inputs a / output, some contact pads of which go to the said surface of the heat-removing base, and others through the through holes in the frame to the outside, while the ceramic-metal inputs / outputs are connected to the frame by solder.

In which the heat sink base and frame are made in one piece, the last in the form of a rim along its perimeter, with a thickness equal to not more than 2.0 mm, the ceramic-metal inputs / outputs are also made in one piece in the form of a conductor made of metal or an alloy of metals having a low electrical resistance, located inside the tube with an internal cross-sectional size equal to 0.2-1.0 mm made of pre-fired ceramics, cermet inlets / outlets and, respectively, through holes for them in the frame are made of circular cross-section, size whose cross-sections, the length of the ceramic-metal inputs / outputs, as well as the sizes of the cross-sections of their conductors and the size of their contact pads are determined by the given parameters of the semiconductor device, and the contact pads are made at the ends of the ceramic-metal inputs / outputs parallel and / or perpendicular to their axis.

In the heat sink base outside the frame, additional through-holes of circular cross-section can also be made for ceramic-metal inlets / outlets.

The ceramic-metal input / output conductor is made of oxygen-free copper metal, either gold, or silver, or platinum, or a metal alloy, while it may have an interphase active element in the form of titanium or chromium, or manganese, or boron.

So the proposed method of its manufacture, including the sequential manufacture of a heat sink base, a frame with through holes, at least one metal contact pad on one of the surfaces of the said base for the location of the crystal or crystals of the semiconductor device, at least two cermet inputs / outputs, their arrangement in a frame in such a way that some of their contact pads go to the aforementioned surface of the heat sink base, and others through openings in the frame to the outside, and the connection of the ceramic-metal inputs / outputs with the frame by brazing.

In which the heat sink base and the frame are made in a single technological cycle, monolithically, the last from the part of the heat sink base material in the form of a rim along its perimeter, with a thickness equal to not more than 2.0 mm, and the manufacture of ceramic-metal inputs / outputs is carried out by placing a metal or alloy metals having low electrical resistance, inside a tube of a given size, made of pre-fired ceramic, metallized on its outer surface, followed by heating in an ale a ctric furnace with a controlled medium until the metal or metal alloy is completely melted, holding at this temperature for no more than 10 minutes and cooling to room temperature, removing the ceramic-metal inlet / outlet blanks, adjusting them to a predetermined size, and then making contact pads at their ends in parallel and / or perpendicular to their axis, cleaning the cermet inlets / outlets, and connect the cermet inlets / outlets with the frame by brazing along their metallized outer surface.

A frame for cermet inlets / outlets and through holes in it are made in any known manner.

In the manufacture of cermet inlets / outlets, oxygen-free copper or gold, or silver, or platinum is taken as a metal or alloy of metals having low electrical resistance, and an addition of an interphase-active element in the form of titanium or chromium, or manganese, or boron is not more than one weight percent, and metals or metal alloys are placed inside a tube of a given size, made of pre-fired ceramics, in the form of wire, powder, chips, and an adjustable medium a vacuum with helium leakage of at least 1.3 × 10 ^-5 m ³ Pa / s, or a reducing medium of hydrogen or / a mixture of hydrogen with nitrogen with a dew point temperature of not more than -45 ° C, or an inert gas medium, fine-tuning them, to a given size and the manufacture of contact pads at their ends in parallel and / or perpendicular to the axis is carried out by grinding.

When connecting the ceramic-metal inputs / outputs with a brazing frame, the latter is taken in the form of an alloy of oxygen-free copper with silver or gold, or platinum, or germanium, or copper plated on the metallized outer surface of the ceramic-metal inputs / outputs.

The implementation of ceramic-metal inlets / outlets and, respectively, through holes for them of circular cross-section allows, due to the simplicity and greater manufacturability of manufacturing the latter, to perform a heat sink base and a frame for ceramic-metal inlets / outs.

The execution of both the heat-removing base and the frame, and the ceramic-metal inputs / outputs of each, respectively, separately, will allow to exclude solder joints with brazing alloys between the base and the frame, as well as between the metal of the conductor and the ceramic of the input / output, and thereby increase:

firstly, reliability,

secondly, durability, and especially when operating in the regime of high microwave power levels, at which, as you know, thermal loads on structural elements increase, which can cause them to fail.

The necessary and sufficient combination of ceramic-metal inputs / outputs and, respectively, through holes for them in a circular cross-sectional frame and, on the other hand, a heat sink base and a frame for ceramic-metal inputs / outputs, will seamlessly provide:

- improving manufacturability and reducing the complexity of manufacturing due to the possibility of more accurate both manufacturing and pairing of housing elements with their mutual arrangement,

- reduction of overall dimensions.

A method of manufacturing a housing is proposed, in which the very formation of an I / O conductor and its connection with ceramics is carried out in a single technological cycle.

In this case, the connection occurs due to the adhesive and thermal diffusion processes occurring during direct contact of the molten metal or metal alloy of the conductor with the inner surface of the tube made of fired ceramic in the specified controlled environment.

The specified type of connection, which takes place between a metal or an alloy of metals of the conductor and the ceramic of the inputs / outputs, has a sufficiently high reliability and will ensure the tightness of the connection of the ceramic-metal inputs / outputs with the frame.

The implementation of ceramic-metal inputs / outputs from pre-fired ceramics, the firing temperature of which is quite high (1600-1650 ° C), will allow the use of ceramic-metal inputs / outputs as a metal or metal alloy:

a) less refractory metals than, for example, molybdenum or tungsten,

b) but at the same time, which have a melting point higher than the melting point of the solder during subsequent soldering.

And at the same time, and this is no less important, the mentioned metal or alloy of metals should have the lowest possible electrical resistance.

The presence of one of these interphase-active elements increases the wettability and adhesion of the molten metal or metal alloy to the inner surface of the tube made of fired ceramic, and especially in the case of large-size metal-ceramic inlets / outlets and thereby ensures the tightness of the ceramic-metal inlets / outlets.

The ability to use these metals or metal alloys that have low electrical resistance, with the other conditions mentioned, as a conductor of cermet inputs / outputs, will increase the output power of the microwave.

It should be noted that of these, oxygen-free copper and its alloys are most preferable, including in terms of cost.

The implementation of the frame for ceramic-metal inlets / outs of the specified thickness, more than 2.0 mm, on the one hand, is limited by the requirement for the integrity of the frame, and on the other, it is impractical, including due to an increase in weight and size characteristics.

A tube made of fired ceramics with the indicated small internal diameter equal to 0.2-1.0 mm during the melting of a metal or metal alloy of a conductor in it, due to the action of forces caused by capillary pressure, ensures both the filling of the tube with the melt and the necessary contact and adhesion of the melt to its inner surface, and thereby ensures high reliability and tightness of the aforementioned thermal diffusion compound of a metal or alloy of a conductor with fired ceramic inlets / outlets.

The controlled environment in its indicated variants provides the necessary technological conditions, including those that exclude the possibility of oxidation of the conductor material.

In addition, the exclusion of expensive molybdenum and tungsten materials as a conductor of cermet inlets / outlets is also important.

In addition, the proposed housing design for microwave semiconductor devices will provide:

- the possibility of using well-known group methods in the manufacture of the body,

- the possibility of reliable planar connection of the case with other elements of devices and systems of microwave electronic equipment, as in some approximation we can consider the design of ceramic-metal input / output in the form of a strip line.

Thus, the totality of the proposed features of each independent claim of both the device — the case and the method of its manufacture will provide the indicated technical result, namely, an increase in reliability and durability, an increase in the microwave output power, an increase in manufacturability and a decrease in the manufacturing complexity, and a decrease in weight and size characteristics.

The invention is illustrated by the drawing, which shows a section of the proposed housing for a microwave semiconductor device and ceramic-metal input / output, respectively, and is indicated: a heat sink 1, a frame for ceramic-metal inputs / outputs 2, a metal contact pad for arranging a crystal or crystals of a microwave semiconductor device 3, ceramic-metal inputs / conclusions 4, with pads made at their ends, parallel to their axis 5.

Example 1

The manufacture of the housing, for example, for a microwave field effect transistor, is considered.

Production of a heat sink base 1 and a frame with through holes for cermet inputs / outputs 2

To do this, take a plate of heat-conducting material, for example, of oxygen-free copper, the size corresponding to the size of the heat-removing base 1. On one of its surfaces from the part of its material, along its perimeter, frame 2 is made in the form of a side equal to 1 mm thick, for example, by milling.

Then, in the frame-side, through holes of circular cross section with a size equal to 0.6 mm are made for the arrangement of ceramic-metal inputs / outputs 4, for example, by drilling.

Then, on the mentioned surface of the heat sink base 1, a metal contact pad 3 is made for arranging and connecting the crystal of the microwave field-effect transistor.

Production of cermet inputs / outputs 4

To do this, take a tube made of pre-fired ceramics, for example VK 94-1, with a size of its internal cross section equal to 0.5 mm, metallize it on the outer surface, for example, with PSTM-1 paste. Next, oxygen-free copper is placed inside the tube, for example, in the form of a wire equal to the length of the tube or with protruding ends. Then, the aforementioned is placed in an electric furnace with a controlled medium, for example, dry hydrogen with a dew point temperature not higher than -20 ° C, heated to the melting temperature of oxygen-free copper and kept at a temperature of 1083-1150 ° C for 5 minutes, cooled to room temperature.

The billet of ceramic-metal inputs / outputs 4 is removed from the electric furnace, they are finished to a predetermined size and contact pads are made at their ends parallel to their axis by grinding, then the ceramic-metal inputs / outputs are cleaned, for example, in acetone using ultrasound.

Next, the manufactured ceramic-metal inputs / outputs 4 in the frame 2 are placed, with some contact pads to the mentioned surface of the base 1, and others - through the through holes in the frame outwards, and the ceramic-metal inputs / outputs are connected to the frame by brazing, for example ПСр-72 V, according to their metallized outer surface.

Examples 2-3.

Analogously to example 1, housings for a microwave field-effect transistor were made, but for other values of the frame thickness and the size of the internal section of the tube made of pre-fired ceramics specified in the claims.

The manufactured housing samples for the microwave field-effect transistor were tested for tightness and reliability.

Tightness was determined using a helium leak detector type PTI-10 according to technical requirements according to OST 11 332.702-89.

Reliability assessment for tightness and preservation of integrity was carried out by thermal cycling under a certain mode according to OST 11 332.702-89 and additional thermal cycles according to the “Application” mode, table 1, until they lost their tightness.

As the test results showed, the fabricated housing samples had a leak-tightness of helium leakage of not more than 1.33 × 10 ^-11 m ³ Pa / s.

Their tightness and integrity were preserved both after the main thermal cycling and 30 additional thermal cycles.

Thus, the proposed housing for a semiconductor microwave device, and the method of its manufacture, will allow, in comparison with the prototype, to increase:

firstly, reliability,

secondly, durability and especially when working in the mode of high microwave power levels,

thirdly, the microwave power output.

And also to increase manufacturability and reduce the complexity of manufacturing, reduce weight and size characteristics.

In addition, the proposed housing design will provide:

- the possibility of using well-known group methods in the manufacture of the body,

- the possibility of reliable planar connection of the housing with other elements of devices and systems of microwave electronic equipment.

In addition, the saving of expensive materials such as molybdenum and tungsten.

The source of information

1. Colloq. Microwave Packag., London, 14 Apr. 1986. Electron. Div, PGE 12. London, 1986.

Claims (7)

1. A housing for a microwave semiconductor device, comprising a heat sink base, a frame with through holes for ceramic-metal inputs / outputs, located on one of the surfaces of the heat sink base around its perimeter, at least one metal contact pad for arranging and subsequently connecting a crystal to it or crystals of a semiconductor device located on said surface of the heat sink base, at least two metal-ceramic I / O, one contact plate the plots of which extend onto the said surface of the heat sink base, and others through the through holes in the frame to the outside, while the ceramic-metal inputs / outputs are connected to the frame by brazing alloy, characterized in that the heat sink base and frame are made in one piece, the latter being in the form of a rim along its perimeter , with a thickness equal to not more than 2.0 mm, cermet inputs / outputs are also made in one piece in the form of a conductor of metal or an alloy of metals having a low electrical resistance located inside the tube the size of the internal section equal to 0.2-1.0 mm made of pre-fired ceramic, the ceramic-metal inputs / outputs and, respectively, the through holes for them in the frame are made of circular cross section, the cross-sectional size of which, the length of the ceramic-metal inputs / outputs, as well as the dimensions of the cross-sections their conductors and the size of their contact pads are determined by the given parameters of the semiconductor device, and the contact pads are made at the ends of the ceramic-metal inputs / outputs parallel and / or perpendicular to their axis. 2. The housing for the microwave semiconductor device according to claim 1, characterized in that additional through holes of circular cross section for ceramic-metal inlets / outlets can be made in the heat sink base. 3. The case for a microwave semiconductor device according to claim 1, characterized in that the ceramic-metal input / output conductor is made of oxygen-free copper metal, or gold, or silver, or platinum, or a metal alloy, while it may have an addition of an interphase element in the form of titanium either chromium, or manganese, or boron. 4. A method of manufacturing a housing of a microwave semiconductor device, comprising sequentially manufacturing a heat sink base, a frame with through holes of at least one metal contact pad on one of the surfaces of said base for arranging a crystal or crystals of a semiconductor device of at least two ceramic-metal inputs / conclusions, their location in the frame so that some of their contact pads go to the aforementioned surface of the heat sink base, and others - through the through holes in the frame to the outside and the connection of the ceramic-metal inputs / outputs with the frame by brazing, characterized in that the heat sink base and the frame are made in a single technological cycle, monolithically, the latter from a part of the heat sink base material in the form of a side along its perimeter, with a thickness equal to not more than 2.0 mm, and the manufacture of cermet inlets / outlets is carried out by placing a metal or alloy of metals having low electrical resistance inside the tube of a given size made of pre-fired ceramics metallized on its outer surface, followed by heating in an electric furnace with a controlled medium until the metal or metal alloy is completely melted, holding at this temperature for no more than 10 minutes and cooling to room temperature, removing billets of ceramic-metal inputs / outputs , fine-tuning them to a predetermined size and the subsequent manufacture of contact pads at their ends parallel and / or perpendicular to the axis, cleaning ceramic-metal bushings / you water, and connect the ceramic-metal inputs / outputs with the frame by brazing along their metallized outer surface. 5. A method of manufacturing a case of a microwave semiconductor device according to claim 4, characterized in that the frame for cermet inputs / outputs and through holes in it are made in any known manner. 6. A method of manufacturing a case of a microwave semiconductor device according to claim 4, characterized in that in the manufacture of cermet inputs / outputs as a metal or alloy of metals having low electrical resistance, oxygen-free copper or gold, silver, or platinum are taken, while they can be added to the interphase element in the form of titanium or chromium, or manganese, or boron of not more than one weight percent, and metals or metal alloys are placed inside a tube of a given size, made of pre ritelno fired ceramic, in the form of wire, powder, shavings, and serves as a vacuum controlled environment with the inflow of helium is not lower than 1,3 × 10 ^-5 m ³ Pa / s, or a reducing environment - hydrogen or mixture of hydrogen and nitrogen with a dew point of no more than 45 ° C, or an inert gas medium, fine-tuning them to a predetermined size and making contact pads at their ends parallel and / or perpendicular to the axis are carried out by grinding. 7. A method of manufacturing a case of a microwave semiconductor device according to claim 4, characterized in that when connecting the ceramic-metal inputs / outputs to the frame by brazing, the latter is taken in the form of an alloy of oxygen-free copper with silver or gold, or platinum, or germanium, or oxygen-free copper electroplated on the metallized outer surface of ceramic-metal inlets / outlets.