阅读说明：本技术 超宽带复合铁氧体环形器制作方法 (Method for manufacturing ultra-wideband composite ferrite circulator ) 是由 王列松 于 2020-06-28 设计创作，主要内容包括：本发明公开了一种成品率高的的拼接型超宽带复合铁氧体微带环形器制作方法,其步骤如下：步骤1、基片精密抛光：将拼接型超宽带复合铁氧体微带环形器所需的各个基片在使用前进行精密抛光,以控制基片的厚度公差在±5μm以内；步骤2、制作微带电路：在精密抛光的各基片上通过常规的薄膜电路工艺制作出微带金属电路图形,并在各基片背面通过常规的薄膜电路工艺制作背面接地金属层；步骤3、背面制作共晶焊料；步骤4、从背面切割基片；步骤5、紧密拼接共晶焊；步骤6、微带电镀原位连通：在微带金属电路图形上电镀金属层,厚度为4～6μm。(The invention discloses a method for manufacturing a spliced ultra-wideband composite ferrite micro-strip circulator with high yield, which comprises the following steps: step 1, precision polishing of a substrate: precisely polishing each substrate required by the spliced ultra-wideband composite ferrite micro-strip circulator before use to control the thickness tolerance of the substrate within +/-5 mu m; step 2, manufacturing a microstrip circuit: manufacturing a microstrip metal circuit pattern on each precisely polished substrate by a conventional thin film circuit process, and manufacturing a back grounding metal layer on the back of each substrate by the conventional thin film circuit process; step 3, manufacturing eutectic solder on the back; step 4, cutting the substrate from the back; step 5, closely splicing eutectic welding; step 6, micro-strip electroplating in-situ communication: and electroplating a metal layer on the microstrip metal circuit pattern, wherein the thickness of the metal layer is 4-6 mu m.)

1. A method for manufacturing a spliced ultra-wideband composite ferrite micro-strip circulator comprises the following steps:

step 1, precision polishing of a substrate: precisely polishing each substrate required by the spliced ultra-wideband composite ferrite micro-strip circulator before use to control the thickness tolerance of the substrate within +/-5 mu m;

step 2, manufacturing a microstrip circuit: manufacturing a micro-strip metal circuit pattern on each precisely polished substrate by a conventional thin film circuit process, wherein the micro-strip metal circuit pattern is a composite metal film layer consisting of an adhesion layer metal and a conducting layer metal, and the thickness of the micro-strip metal circuit pattern is 0.05-2 mu m; a back grounding metal layer is manufactured on the back of each substrate through a conventional thin film circuit process, the back grounding metal layer is a composite metal film layer formed by adhesion layer metal and conducting layer metal, and the thickness of the back grounding metal layer is 1-5 microns;

step 3, preparing eutectic solder on the back: manufacturing eutectic solder on the back surface of the back surface grounding metal layer of the substrate by a PVD (physical vapor deposition) sputtering/evaporation or alloy electroplating method, wherein the thickness of the eutectic solder is 4-6 mu m;

step 4, cutting the substrate from the back;

step 5, closely splicing eutectic welding: firstly plating a weldable metal film with the thickness not more than 5 mu m on the metal sheet with high magnetic conductivity, then tightly splicing the cut splicing parts together under a tool clamp, and eutectic-welding the splicing parts on the metal sheet with high magnetic conductivity in an eutectic furnace;

step 6, micro-strip electroplating in-situ communication: and electroplating a metal layer on the microstrip metal circuit pattern, wherein the thickness of the metal layer is 4-6 mu m.

2. The manufacturing method of the spliced ultra-wideband composite ferrite micro-strip circulator as claimed in claim 1, characterized in that: the conventional thin film circuit process is a magnetron sputtering/evaporation, or photoetching, or corrosion thin film circuit process.

3. The manufacturing method of the spliced ultra-wideband composite ferrite micro-strip circulator as claimed in claim 2, characterized in that: the microstrip metal circuit pattern is a Ti/Cu, Cr/Cu, TiW/Au or TiW/Cu/Au composite metal film layer.

4. The manufacturing method of the spliced ultra-wideband composite ferrite micro-strip circulator as claimed in claim 3, characterized in that: the thickness of the microstrip metal circuit pattern is 0.2-1 μm.

5. The manufacturing method of the spliced ultra-wideband composite ferrite micro-strip circulator as claimed in claim 2, characterized in that: the back grounding metal layer is a Ti/Cu, Cr/Cu, TiW/Au or TiW/Cu/Au composite metal film layer.

6. The manufacturing method of the spliced ultra-wideband composite ferrite micro-strip circulator as claimed in claim 1, characterized in that: the eutectic solder is one of AuSn, SnSb, SnBi and SnAgCu which are selected according to the required eutectic temperature.

7. The manufacturing method of the spliced ultra-wideband composite ferrite micro-strip circulator as claimed in claim 1, characterized in that: in the step 6, the metal layer electroplated on the microstrip metal layer is a Cu/Au electroplated composite layer or a full-gold electroplated layer.

8. The method for manufacturing the spliced ultra-wideband composite ferrite micro-strip circulator as claimed in claim 7, wherein the method comprises the following steps: the thickness of the Cu layer in the Cu/Au composite layer is 4 mu m, and the thickness of the Au layer is 2 mu m.

9. The manufacturing method of the spliced ultra-wideband composite ferrite micro-strip circulator as claimed in claim 1, characterized in that: and in the step 5, the high-permeability metal sheet is flattened by a flattening machine before being coated with the weldable metal film.

10. The manufacturing method of the spliced ultra-wideband composite ferrite micro-strip circulator as claimed in claim 1, characterized in that: and in the step 5, the weldable metal film plated on the high-permeability metal sheet is a Ni/Au composite layer.

Technical Field

The invention belongs to the technical field of hybrid integrated circuits, and particularly relates to a manufacturing method of an ultra-wideband composite ferrite circulator.

Background

The electromagnetic suppression, electromagnetic interference and anti-interference functions in modern battlefields are increasingly prominent, corresponding electronic equipment is required to have ultra-bandwidth and high-power performance, and the ferrite-based micro-strip circulator becomes a preferred component of the active phased array radar of the modern electronic equipment due to good insertion loss performance, high-power performance and high-bandwidth performance.

Generally, to realize ultra-wideband (more than one octave), a composite ferrite structure with gradually-changed saturation magnetization gradient is adopted in the ferrite micro-strip circulator, and patent application 201911201129.8 discloses a simple and easy spliced ultra-wideband composite ferrite micro-strip circulator structure, as shown in fig. 1. The traditional manufacturing method of the structure is as follows: and welding all cutting units (high saturation magnetization ferrite, low saturation magnetization ferrite and matching circuit medium) on a high-permeability metal sheet through soldering sheets or soldering paste, bonding metal lap joints such as gold wires and gold bands on two sides of a splicing gap, or forming the same microstrip pattern on a medium, and then reversely buckling and welding the microstrip patterns at the gap to realize microstrip communication.

The traditional manufacturing method has no problem when manufacturing a low-frequency or narrow-band device, but the ultra-wideband composite ferrite micro-strip circulator usually works on a high-frequency and ultra-wide frequency band from several GHz to ten and several GHz, and usually requires good amplitude-phase consistency due to a phased array. Such as: because the soldering lug or the soldering paste are relatively thick (generally tens of microns), the soldering lug or the soldering paste can be extruded into a splicing gap by carelessness during soldering, and the electrical property is deteriorated when the soldering lug or the soldering paste is deep into the gap by tens of microns; microstrip communication is realized on the high-frequency ultra-wideband device through metal lapping objects such as gold bonding wires, gold bands and the like, and subsequent heavy debugging is required, even the required performance cannot be realized; the method of making microstrip pattern on the medium and then back-off welding increases the complexity of manufacture on one hand, and on the other hand, the medium is added above the microstrip, so that the microstrip circuit is discontinuous, and the electrical property is easy to be deteriorated.

Therefore, although the ultra-wideband composite ferrite micro-strip circulator with the splicing structure is simpler and more feasible than the ultra-wideband composite ferrite micro-strip circulator with the cylindrical-circular nested structure, if the traditional conventional manufacturing method is used, the problems of heavy subsequent debugging task, low yield and poor consistency can be met during batch production.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the manufacturing method of the spliced ultra-wideband composite ferrite micro-strip circulator with high yield is provided.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a method for manufacturing a spliced ultra-wideband composite ferrite micro-strip circulator comprises the following steps:

step 1, precision polishing of a substrate: precisely polishing each substrate required by the spliced ultra-wideband composite ferrite micro-strip circulator before use to control the thickness tolerance of the substrate within +/-5 mu m;

step 2, manufacturing a microstrip circuit: manufacturing a micro-strip metal circuit pattern on each precisely polished substrate by a conventional thin film circuit process, wherein the micro-strip metal circuit pattern is a composite metal film layer consisting of an adhesion layer metal and a conducting layer metal, and the thickness of the micro-strip metal circuit pattern is 0.05-2 mu m; a back grounding metal layer is manufactured on the back of each substrate through a conventional thin film circuit process, the back grounding metal layer is a composite metal film layer formed by adhesion layer metal and conducting layer metal, and the thickness of the back grounding metal layer is 1-5 microns;

step 3, preparing eutectic solder on the back: manufacturing eutectic solder on the back surface of the back surface grounding metal layer of the substrate by a PVD (physical vapor deposition) sputtering/evaporation or alloy electroplating method, wherein the thickness of the eutectic solder is 4-6 mu m; this can be made relatively thin, which is difficult to do with conventional solder pre-forming or solder paste printing methods. The purpose of thinning is to ensure that solder does not enter a splicing gap (even if the solder enters a splicing gap very little, the solder can be ignored) during the close splicing eutectic welding, and on the other hand, to ensure that all splicing parts are almost on the same plane after the close splicing eutectic welding (if the solder is thicker, the splicing parts are not on the same plane after the welding due to the difference of the extrusion of the solder during the eutectic liquefaction of the solder).

Step 4, cutting the substrate from the back;

step 5, closely splicing eutectic welding: firstly plating a weldable metal film with the thickness not more than 5 mu m on the metal sheet with high magnetic conductivity, then tightly splicing the cut splicing parts together under a tool clamp, and eutectic-welding the splicing parts on the metal sheet with high magnetic conductivity in an eutectic furnace;

step 6, micro-strip electroplating in-situ communication: and electroplating a metal layer on the microstrip metal circuit pattern, wherein the thickness of the metal layer is 4-6 mu m. Because metal can not be electroplated on the ceramic except the micro-strip pattern, and because the gap at the splicing part is very small, the micro-strip metals at two sides of the gap extend mutually during electroplating, the electroplating in-situ communication is realized (generally, the electroplating speed at the gap is higher than that on the micro-strip plane, and the reliability of the micro-strip electroplating in-situ communication is further ensured).

Therefore, after the following close splicing eutectic welding, the splicing parts are almost in the same plane, so that the continuity of the micro-strip is kept, the electrical property of the high-frequency ultra-wideband is guaranteed, and the reliability of the in-situ connection of the following micro-strip electroplating is also guaranteed.

Preferably, the conventional thin film circuit process is a magnetron sputtering/evaporation, or photolithography, or etching thin film circuit process.

Preferably, the microstrip metal circuit pattern is a Ti/Cu, Cr/Cu, TiW/Au or TiW/Cu/Au composite metal film layer.

Preferably, the thickness of the microstrip metal circuit pattern is 0.2-1 μm.

Preferably, the back grounding metal layer is a Ti/Cu, Cr/Cu, TiW/Au, or TiW/Cu/Au composite metal film layer.

Preferably, the eutectic solder is one of AuSn, SnSb, SnBi and SnAgCu selected according to a desired eutectic temperature.

In a preferable embodiment, in step 6, the metal layer electroplated on the microstrip metal layer is a Cu/Au electroplated composite layer or a full gold electroplated layer.

In a preferred embodiment, the thickness of the Cu layer in the Cu/Au composite layer is 4 μm, and the thickness of the Au layer is 2 μm.

Preferably, in step 5, the high-permeability metal sheet is flattened by a flattening machine before being coated with the weldable metal film, so as to ensure that the splicing parts can be in close contact and in the same plane during splicing.

Preferably, the weldable metal film plated on the high-permeability metal sheet in step 5 is a Ni/Au composite layer.

The invention has the beneficial effects that: the invention provides a method for micro-strip electroplating in-situ communication, which ensures that micro-strip circuits on two sides of a splicing gap are mutually extended through electroplating and then accurately stitched in situ, is similar to a micro-strip circuit manufactured at one time, and avoids the problems of heavy debugging brought by traditional gold wire gold strip bonding and micro-strip circuit discontinuity caused by micro-strip medium back-off welding.

In order to avoid the problem that the soldering lug/soldering paste is likely to be extruded into a splicing gap due to the fact that the soldering lug/soldering paste is thick (usually tens of microns) in eutectic soldering, eutectic solder with the thickness of 4-6 microns is manufactured on the back surface (eutectic soldering surface) of a substrate in advance by the aid of PVD (vacuum sputtering or evaporation), alloy electroplating and other methods, so that good eutectic soldering is guaranteed, and the problem that the solder is extruded into the splicing gap due to the fact that the solder is thick is avoided.

In order to further improve the splicing tightness, reduce the splicing gap and provide reliability and stability for the subsequent micro-strip pattern electroplating in-situ communication, and considering the characteristic that a cutting surface has a slight inclination when a dicing saw cuts a ceramic wafer, the invention adopts a mode of cutting from the back surface when cutting a substrate, so that after the splicing parts are subjected to splicing eutectic welding, the distances between micro-strip metals on two sides of the splicing gap are very close (less than 5 micrometers, most of the micro-strip metals are in direct contact without gaps), and the high-reliability guarantee is provided for the subsequent micro-strip pattern electroplating in-situ communication.

Drawings

FIG. 1 is a schematic structural diagram of a spliced ultra-wideband composite ferrite micro-strip circulator.

FIG. 2 is a schematic diagram of a manufacturing process of the spliced ultra-wideband composite ferrite micro-strip circulator.

Detailed Description

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in fig. 2, a method for manufacturing a spliced ultra-wideband composite ferrite micro-strip circulator includes the following steps:

1) precision polishing of the substrate: three substrates are selected to manufacture the spliced ultra-wideband composite ferrite micro-strip circulator which is a 2500Gauss high saturation magnetization ferrite substrate, a 1400Gauss low saturation magnetization ferrite substrate and a 99.5% alumina ceramic substrate. The three substrates are two-inch square sheets, and are subjected to rough polishing and precision polishing to obtain the substrate with the thickness range of 0.4 mm-0.406 mm.

2) Manufacturing a micro-strip circuit: positioning holes (with the diameter of phi 0.4 mm) are punched at four corners of the three substrates through laser (used for photoetching positioning and subsequent back cutting positioning), then TiW (50nm)/Au (0.5 mu m) is subjected to magnetron sputtering on the front side, TiW (50nm)/Cu (3 mu m) Au (0.1 mu m) is subjected to magnetron sputtering on the back side, and finally a microstrip metal circuit pattern is manufactured on the front side through photoetching and corrosion.

3) Preparing eutectic solder on the back: Au-Sn (80/20) alloy with the thickness of 4 μm is electroplated on the back of the substrate as eutectic solder by alloy electroplating method.

4) Cutting the substrate from the back side; the substrate is cut from the back side to obtain the splicing members.

5) Closely splicing eutectic welding: the cut splicing parts are tightly spliced together under a tool fixture, and eutectic welding is carried out at 295 degrees in an eutectic furnace on a high-permeability metal sheet with the thickness of 0.5mm (the metal sheet is subjected to flattening treatment in advance and plated with Ni (3 mu m)/Au (0.5 mu m)).

6) Micro-strip electroplating in-situ communication: after the close splicing eutectic welding is finished, a metal layer is electroplated on the microstrip metal circuit pattern, and the metal layer is 5 mu m thick gold, so that the in-situ communication of the microstrip circuit is realized.

The spliced ultra-wideband composite ferrite micro-strip circulator prepared in the way is placed under a body type microscope and a high-power metallographic microscope for observation, the spliced part has no any gap, the micro-strips are all communicated, and the device is similar to a one-time manufacturing device.

The above-mentioned embodiments are merely illustrative of the principles and effects of the present invention, and some embodiments may be used, not restrictive; it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the inventive concept of the present invention, and these changes and modifications belong to the protection scope of the present invention.