阅读说明：本技术 基于钛基板电镀图形转移方法制成的ltcc器件 (L TCC (cross-resistance coefficient) device manufactured based on titanium substrate electroplating pattern transfer method ) 是由 王翀 苏亚东 何为 陈苑明 周国云 洪延 王守绪 于 2020-03-27 设计创作，主要内容包括：本发明提供一种基于钛基板电镀图形转移方法制成的LTCC器件,根据设计的电路图形,在钛基板表面制作抗电镀掩膜；将钛基板进行电镀制作铜线路图形；去除抗电镀掩膜后直接进行陶瓷浆料的流延；烘烤、干燥、剥离制得LTCC生瓷片；将制得的不同层的LTCC生瓷片经叠片、等静压、烧结过程制得LTCC器件。本发明提出了通过电镀的方法加成制作LTCC的内电极电子互连铜线路,能够改善现有LTCC制造技术对电子浆料的依赖,解决大部分因电子浆料自身缺陷造成的技术问题,有效提高封装基板电子互连电路的可靠性和稳定性。(The invention provides a L TCC device manufactured based on a titanium substrate electroplating pattern transfer method, which is characterized in that an anti-electroplating mask is manufactured on the surface of a titanium substrate according to a designed circuit pattern, a copper circuit pattern is manufactured by electroplating the titanium substrate, casting of ceramic slurry is directly performed after the anti-electroplating mask is removed, a L TCC green ceramic chip is manufactured by baking, drying and stripping, and L TCC devices are manufactured by laminating, isostatic pressing and sintering the L TCC green ceramic chips of different layers.)

1. An L TCC green ceramic chip manufactured based on a titanium substrate electroplating pattern transfer method is characterized in that the method comprises the steps of manufacturing an anti-electroplating mask on the surface of a titanium substrate according to a designed circuit pattern, electroplating the titanium substrate to manufacture a copper circuit pattern, removing the anti-electroplating mask, directly carrying out tape casting on ceramic slurry, baking, drying and peeling to manufacture the L TCC green ceramic chip.

2. The L TCC green ceramic tile of claim 1, wherein the process of making the plating-resistant mask is as follows:

the titanium substrate with a smooth and flat surface is used as a supporting substrate, and an anti-electroplating mask is manufactured on the surface of the titanium substrate by adopting a screen printing or laser engraving method according to a circuit pattern designed by a design drawing.

3. The L TCC green ceramic tile of claim 2, wherein the titanium substrate has a surface grain size of ASTM grade 7 or less, and a surface roughness Ra < 0.6 μm;

when a circuit pattern is manufactured, the surface of a titanium substrate needs to be kept clean and smooth;

the electroplating-resistant mask is made of photoresist, a mixture of titanium dioxide and the photoresist, or solder resist ink;

the process for manufacturing the electroplating-resistant mask comprises the following steps: after the anti-electroplating mask is manufactured on the surface of the titanium substrate by adopting a screen printing or laser engraving method, the anti-electroplating mask is fixed by a photocuring or thermocuring method.

4. The L TCC green ceramic tile of claim 1, wherein said electroplating is performed as follows:

and electroplating by taking the prepared titanium substrate attached with the electroplating-resistant mask as a cathode and the copper ion solution as electroplating solution to obtain a copper circuit pattern with the thickness meeting the design requirement.

5. The L TCC green ceramic tile of claim 4,

the electroplating solution is an acidic copper sulfate copper electroplating solution system which contains copper sulfate, sulfuric acid, chloride ions and a very small amount of copper electroplating additives;

in the electroplating process, the thickness of copper in the copper circuit pattern is accurately adjusted by controlling the current density and the electroplating time.

6. The L TCC green ceramic chip according to claim 1, wherein the L TCC green ceramic chip is prepared by removing the plating-resistant mask to obtain a groove, casting the low-temperature co-fired ceramic slurry into the groove by a casting machine to form a film, baking and drying.

7. The L TCC green ceramic tile of claim 6, wherein the thickness of the membrane in the L TCC green ceramic tile is controlled according to slurry viscosity and casting speed and is kept consistent with the thickness of the copper wire;

the electroplating-resistant mask needs to be stripped by adopting a stamping, laser cutting or etching method, and the L TCC green ceramic chip is modified by adopting a grinding, polishing or trimming or cutting method, and then the scraper slides slightly along the edge of the titanium substrate to rapidly strip the green ceramic chip containing the copper circuit, so that the electroplating-resistant mask is obtained.

8. An L TCC device manufactured by a titanium substrate electroplating pattern transfer method, which is characterized in that the L TCC green ceramic chips with different patterns according to any one of claims 1 to 7 are subjected to lamination, isostatic pressing and sintering to manufacture a L TCC device.

9. The L TCC device of claim 8, wherein said L TCC device is made by the process of:

laminating, namely using a laminating device to align and laminate processed L TCC (ceramic green sheets) according to a given design sequence by using a laser or positioning pin alignment method or an image identification and positioning method for punching positioning holes to form a three-dimensional interconnected circuit structure;

isostatic pressing, namely pressing the processed L TCC green ceramic sheets into a compact state by using an isostatic press so as to control the shrinkage rate in the sintering process;

sintering, namely sintering the laminated L TCC green ceramic chips in a sintering furnace at a temperature range of 850-950 ℃ according to a process given program to complete densification and hardening of the ceramic, and cutting the sintered L TCC product to a required size by using a dicing saw to obtain the ceramic.

10. The multilayer low-temperature co-fired ceramic is characterized by comprising ceramic layers, wherein copper circuits are arranged in the ceramic layers and are used as conductive materials to realize electrical interconnection, and further preferably, the ceramic layers are L TCC (cross resistance) devices in any one of 8-9.

Technical Field

The invention relates to the technical field of low-temperature co-fired ceramics, in particular to an L TCC (cross resistance coefficient) device manufactured based on a titanium substrate electroplating pattern transfer method.

Background

With the higher demands on data and current density transmission of the fifth generation communication technology, the electronic interconnection circuits are increasingly developed toward miniaturization, high frequency, high integration and high density, which requires new breakthroughs in the size, design, reliability and integration methods of electronic components.

The L TCC packaging substrate has excellent high-frequency characteristic and high reliability, can replace discrete elements such as resistors, capacitors and the like to a great extent, meets the design requirements of small volume, high performance and low cost, shortens the design period and the cost of the whole module, has good high-speed transmission performance, microwave performance and extremely high integration level, and has the advantages of low dielectric loss, low sintering temperature, low process cost and the like, and has very wide application prospect.

Specifically, L TCC technology is to make low temperature sintered ceramic powder slurry and flow into dense green ceramic tape with precise thickness, to make the required circuit pattern on the green ceramic sheet by using laser drilling, through hole filling, inner electrode printing and other processes, to embed a plurality of passive components (such as low-capacitance value capacitor, resistor, filter, impedance converter, coupler and the like) into a multilayer ceramic substrate, then to laminate together, the inner and outer electrodes can use silver, copper, gold and other metals respectively, to sinter at 900 ℃, L can make two-dimensional space non-interfering high-density circuit, to make three-dimensional circuit package substrate by using its high integration, to mount TCC IC and active elements on its surface, to further make the circuit small-sized and high-density, especially suitable for high frequency communication components.

Since L TCC is a multilayer ceramic technology, which is provided with electronic circuits on each layer and connects them with each other, these electronic circuits are also called internal electrode circuits, and include an interconnection circuit pattern in the layer and a metal via between the layers, and their manufacturing methods are generally classified into three types, a subtractive method, an additive method and a semi-additive method.

The electronic paste for making the inner electrode circuit pattern is actually a paste consisting of uniform ultrafine metal particles or metal compounds, cosolvent, binder, solvent and the like, and is added with glass powder and additives to achieve the required functions. Also, the metal powder as a conductive material affects not only the conductive properties of the sintered film but also the physical and mechanical properties of the sintered film. The metal powder material for the electronic paste can be one or more of gold, silver, copper and other noble metals, and performance parameters such as the morphology, the particle size, the tap density, the specific surface area and the like of the metal powder can influence the rheological property and the sintering morphology of the conductive paste and determine the quality of the electrical performance of the sintered electrode. The inorganic binding phase of the conductive slurry is mostly glass powder, and the glass powder can play a role in fixing metal particles in the sintering process.

TABLE 1 physical Properties of commonly used Metal materials

The electronic paste for manufacturing L TCC inner electrode is mostly conductive silver paste, and is prepared by using superfine silver powder as a conductive phase, and the silver particles can form an electronic circuit to realize electrical communication after drying and sintering, the silver powder is selected as the conductive phase in the prior art, because the melting point of the silver is higher than the sintering temperature of ceramic (see table 1), the silver is not melted and deformed, and the reliability of the circuit is influenced, and the silver has high thermal conductivity and low resistivity, and is very beneficial to reducing the loss and distortion of signals in a high-frequency circuit.

In addition, the problems that the requirement for metal powder is high in preparation of conductive paste, the aspects of morphology, particle size, tap density, specific surface area and the like are limited, and the process threshold is high in the conventional L TCC multilayer ceramic packaging substrate are avoided when the conductive paste is used for manufacturing electronic interconnection circuits, a chemical reduction method is generally adopted for preparing superfine metal powder of the conductive paste industrially, a large amount of strong reducing agents such as formaldehyde are needed, the reducing agents are polluted greatly, waste liquid treatment is difficult, a large amount of noble metal silver is needed for manufacturing internal electrode circuits by using the conductive paste, the cost is higher than that of copper interconnection electronic circuits of other packaging substrates, dust and toxic smoke are generated in the preparation and use processes of an inorganic bonding phase of the conductive paste and low-melting glass, elements harmful to human health and environment are contained in the glass composition, various organic supporting phases of the conductive paste contain various organic solvents and auxiliary agents, and the ceramic is volatilized and permeated into the circuits in the printing, drying and sintering processes, so that the manufactured circuits are not high in density, even pores and collapse are generated, and the reliability of the electronic interconnection circuits is certain problem.

Disclosure of Invention

The invention provides an L TCC device manufactured by a titanium substrate electroplating pattern transfer method, provides an inner electrode electronic interconnection copper circuit of L TCC manufactured by an electroplating method, can improve the dependence of the existing L TCC manufacturing technology on electronic paste, solves the technical problems caused by the defects of the electronic paste, and effectively improves the reliability and stability of an electronic interconnection circuit of a packaging substrate.

In order to solve the technical problems, the invention provides the following technical scheme:

on one hand, the invention provides an L TCC (TCC) green ceramic chip manufactured based on a titanium substrate electroplating pattern transfer method, which comprises the steps of manufacturing an anti-electroplating mask on the surface of a titanium substrate according to a designed circuit pattern, electroplating the titanium substrate to manufacture a copper circuit pattern, removing the anti-electroplating mask, directly carrying out tape casting on ceramic slurry, baking, drying and stripping to manufacture the L TCC green ceramic chip.

Further, the process for manufacturing the electroplating-resistant mask comprises the following steps:

the titanium substrate with a smooth and flat surface is used as a supporting substrate, and an anti-electroplating mask is manufactured on the surface of the titanium substrate by adopting a screen printing or laser engraving method according to a circuit pattern designed by a design drawing.

Further, the surface grain size of the titanium substrate should be in ASTM grade 7 or less, and the surface roughness Ra < 0.6 μm;

when a circuit pattern is manufactured, the surface of a titanium substrate needs to be kept clean and smooth;

the electroplating-resistant mask is made of photoresist, a mixture of titanium dioxide and the photoresist, or solder resist ink;

the process for manufacturing the electroplating-resistant mask comprises the following steps: after the anti-electroplating mask is manufactured on the surface of the titanium substrate by adopting a screen printing or laser engraving method, the anti-electroplating mask is fixed by a photocuring or thermocuring method.

Further, the electroplating process is as follows:

and electroplating by taking the prepared titanium substrate attached with the electroplating-resistant mask as a cathode and the copper ion solution as electroplating solution to obtain a copper circuit pattern with the thickness meeting the design requirement.

Further, the electroplating solution is an acid copper sulfate copper electroplating solution system which contains copper sulfate, sulfuric acid, chloride ions and a very small amount of copper electroplating additives;

in the electroplating process, the thickness of copper in the copper circuit pattern is accurately adjusted by controlling the current density and the electroplating time.

Further, the L TCC green ceramic chip is prepared by removing the prepared electroplating-resistant mask to obtain a groove, injecting low-temperature co-fired ceramic slurry into the groove through a casting machine to cast into a membrane, and baking and drying.

Further, the thickness of the membrane in the L TCC green ceramic chip is controlled according to the viscosity of the slurry and the casting speed, and is kept consistent with the thickness of the copper circuit;

the electroplating-resistant mask needs to be stripped by adopting a stamping method, a laser cutting method or an etching method.

Further, after the L TCC green ceramic chip is modified by adopting a grinding, polishing or cutting method, the green ceramic chip containing the copper circuit is rapidly peeled off by slightly sliding a scraper along the edge of the titanium substrate, so as to obtain the ceramic chip.

In another aspect, the present invention provides an L TCC device made by the method of transferring electroplating patterns on a titanium substrate, wherein the L TCC green ceramic chip of any one of claims 1 to 7 with different patterns is laminated, isostatic pressed and sintered to make a L TCC device.

In one aspect, the invention provides an L TCC device manufactured based on a titanium substrate electroplating pattern transfer method, which comprises the following specific preparation processes:

1) manufacturing an electroplating-resistant mask: a titanium substrate with a smooth and flat surface is used as a supporting substrate, and an anti-electroplating mask is manufactured on the surface of the titanium substrate by adopting methods such as silk-screen printing or laser engraving according to a circuit pattern designed by a design drawing;

the surface grain size of the used titanium substrate is ASTM grade 7 or less, the surface roughness Ra is less than 0.6 μm, the surface of the titanium substrate needs to be kept clean when a circuit pattern is manufactured, the manufactured circuit is prevented from being open-circuited or short-circuited, the subsequent process is convenient to separate from a finished product, and the titanium substrate can be reused when the surface is ensured to be smooth; the titanium substrate has a certain thickness to ensure the mechanical strength of the titanium substrate and reduce the problem of the reduction of the reliability of the circuit caused by the deformation of the titanium substrate;

the electroplating-resistant mask can be made of photoresist (namely photoresist), a mixture of titanium dioxide and the photoresist, solder resist ink and the like, a mask pattern can be fixed on the surface of a bright titanium substrate by a photocuring or thermocuring method, and the mask can be completely removed after electroplating; the anti-plating mask should be insoluble in water but needs to be removed in subsequent processes;

2) electroplating a circuit: electroplating by taking the titanium substrate attached with the electroplating-resistant mask prepared in the step 1) as a cathode and a copper ion solution as electroplating solution to obtain a copper circuit pattern with the thickness meeting the design requirement;

the electroplating copper plating solution for manufacturing the circuit pattern adopts an electroplating solution system which can not react with an anti-electroplating mask, the prepared copper layer is bright and compact so as to ensure the reliability of the circuit, and the electroplating solution can be repeatedly used when being well maintained;

the electroplating solution is generally an acidic copper sulfate copper electroplating solution system, which contains copper sulfate, sulfuric acid, chloride ions and a very small amount of copper electroplating additives, and can be used for a long time after simple maintenance;

in the electroplating process, the thickness of copper in the copper circuit pattern is accurately adjusted by controlling the current density and the electroplating time;

as the conditions for the plating treatment, the conventionally known conditions can be applied, for example, the cathodic current density is 0.05 to 5A/dm²Preferably 0.5 to 3A/dm². The anode may be a known one, a soluble anode such as a copper plate, or an insoluble anode, and the plating temperature is 15 to 35 ℃, preferably 22 to 28 ℃. Reference may also be made to electroplating techniques mentioned in the prior art, for example CN201010293494.9, CN2000811809.4, CN2002128625.6, CN2002140504.2, etc.;

3) stripping and casting: removing the electroplating-resistant mask prepared in the step 2) to obtain a groove, casting the low-temperature co-fired ceramic slurry into a membrane in the groove through a casting machine, baking and drying to volatilize an organic solvent in the slurry, and forming a green ceramic sheet with certain strength and toughness;

in the process of the step, the slurry is tightly combined with the copper circuit without bubbles, the thickness of the diaphragm can be controlled according to the viscosity of the slurry and the casting speed, and the thickness of the diaphragm is kept consistent with that of the copper circuit;

the low-temperature co-fired ceramic slurry used for casting can be prepared by adopting a commercial formula, but the green ceramic chip dried and formed after casting needs to be ensured to have certain strength and toughness, so that cracks or direct cracking caused by uneven stress during drying and stripping are avoided;

when the casting membrane is dried, the size and the volume of the casting membrane can be shrunk along with the volatilization of the organic solvent, the binding force between the green ceramic chip and the titanium substrate with a smooth surface is small, and the green ceramic chip and the copper wire can be completely stripped from the titanium substrate under the condition of certain strength and toughness;

the method for removing the electroplating-resistant mask can be a conventional method, the completeness of the stripping of the electroplating-resistant mask is ensured, and methods such as stamping, laser cutting and etching can be adopted, or the methods related to the prior technical schemes CN201210262373.7, CN201210501786.6, CN201610307546.0 and the like are referred.

4) Stripping: slightly sliding the green ceramic chip obtained in the step 3) along the edge of the titanium substrate by using a scraper so as to quickly peel off the green ceramic chip containing the copper circuit;

before the green ceramic chip is peeled off from the surface of the titanium substrate, the green ceramic chip is required to be modified, and the modification method can adopt methods such as but not limited to grinding, polishing, trimming, cutting and the like, so that the interface of an interlayer copper electronic interconnection circuit is coplanar with the interface of the green ceramic chip, the good contact of the circuits between different layers can be ensured when the subsequent alignment lamination is carried out, and the reliability of the circuit is ensured;

5) repeating the steps 1) to 4), manufacturing L TCC green ceramic chips with different layers, wherein the ceramic chips have the same or different inner electrode circuits;

6) stacking, namely using a stacking device to align and stack processed L TCC (TCC) green ceramic chips according to a given design sequence by using a laser or positioning pin alignment method or an image identification and positioning method through punching positioning holes to form a three-dimensional interconnected circuit structure, wherein in the process, the good contact of inner electrode circuits among layers is ensured;

7) isostatic pressing, namely pressing the processed L TCC green ceramic sheets into a compact state by using an isostatic press so as to control the shrinkage rate in the sintering process;

8) sintering, namely sintering the laminated L TCC green ceramic chip in a sintering furnace at a temperature range of 850 ℃ to 950 ℃ according to a process given program to complete the densification and hardening of the ceramic;

9) and (4) finishing, namely cutting the sintered L TCC product to a required size by using a dicing saw, and completing the size, appearance and electrical property test of the product.

The ceramic layer is made of L TCC devices, namely L TCC devices or single-layer or multi-layer L TCC green ceramic chips.

Further, the spacing between adjacent copper lines is less than 45 μm, preferably less than 25 μm, and may be as low as 1-2 μm.

Further, the thickness of each of the copper lines is 2 to 50 μm, preferably 5 to 25 μm.

Further, the resistivity of each of the copper lines is less than 10 μ Ω · cm, preferably less than 2 μ Ω · cm.

Further, the material of each ceramic layer can be selected from amorphous glass, glass ceramic (microcrystalline glass), and glass/ceramic composite material, preferably glass/ceramic composite material, such as borosilicate glass/alumina composite material.

Furthermore, each ceramic layer and the copper circuit arranged in the ceramic layer are well combined and are not separated or warped under the high-temperature working environment of more than 100 ℃.

The electronic interconnection circuit is in electrical communication with various embedded and mounted components in the L TCC multilayer ceramic packaging substrate, and circuits which are not interfered with each other and have high density in a three-dimensional space can be manufactured after the ceramic substrate is sintered.

The invention provides an inner electrode electronic interconnection copper circuit of L TCC (transmission resistance coefficient) manufactured by an electroplating method in an additive mode, which can improve the dependence of the existing L TCC manufacturing technology on electronic paste, solve the technical problems caused by the defects of the electronic paste, and effectively improve the reliability and stability of the electronic interconnection circuit of a packaging substrate.

Advantageous effects

Compared with the prior art, the invention has the following beneficial effects:

the invention provides an L TCC device prepared by a titanium substrate electroplating pattern transfer method, wherein the prepared L TCC device can overcome the defects of a traditional conductive silver paste circuit, copper is innovatively applied to a L TCC green ceramic chip circuit in a copper electroplating mode, the limitation of the metal powder appearance, the particle size, the tap density, the specific surface area and the like in conductive paste can be avoided, the problems of pollution, health damage and the like in the industrial conductive paste manufacturing process are avoided, noble metal is avoided, and the influence of an organic support phase on the reliability of an electronic lug connection circuit in the drying or sintering process is avoided.

Compared with the traditional electronic interconnection circuit made of conductive silver paste, the electronic circuit is made by adopting copper electroplating, and the electronic interconnection circuit is only made in copper-containing electroplating solution, so that silver particles with higher specifications and various organic auxiliaries are avoided, and the electroplating solution can be repeatedly used for a long time; as shown in fig. 2(a) and (b), the electronic interconnection circuit manufactured by using the conductive silver paste mainly realizes electrical interconnection through ultrafine metal particles uniformly dispersed in the electronic paste, and organic solvents and additives in the conductive silver paste may escape from the interconnection circuit during drying, molding and sintering, so that phenomena such as circuit looseness, hole filling gaps and the like are caused, and the reliability of the circuit is low; the addition manufacturing method adopts electroplating to manufacture the circuit, can manufacture a compact and flat pure metal circuit by adjusting the composition of the plating solution and the electroplating parameters, has the specific effects shown in fig. 2(c) and (d), has excellent performances in signal transmission, heat dissipation and other aspects, and has higher reliability of electronic interconnection circuits;

compared with the traditional screen printing missing method, the circuit manufacturing is realized through electroplating, the high current efficiency of the electroplated copper can realize the high utilization rate of the copper, the used copper electroplating solution is stable in property and can be repeatedly used, and the problem that the circuit needs to be used up at one time can not exist (the traditional L TCC manufacturing technology usually adopts a screen printing missing mode to manufacture electronic interconnection circuits, each circuit pattern needs to be manufactured with a screen printing plate independently, silver paste on the screen needs to be used up at one time, otherwise, the circuit is solidified and scrapped);

compared with the traditional screen printing method, the thickness of an electronic circuit is controlled by applying pressure to the screen printing plate, the method is substantially a physical coating, is greatly influenced by the rheological property of conductive silver paste, and is difficult to control the precision; the addition manufacturing method of the invention depends on electrochemical reaction to electrically reduce the copper ions in the plating solution into metal copper, and the thickness of the circuit can be accurately adjusted by controlling the current density and the plating time;

the method comprises the steps of manufacturing an anti-electroplating mask, removing the anti-electroplating mask, casting a film, utilizing a designed circuit pattern in a close fit manner in the whole process, ensuring the reliability of the copper circuit, solving the problem of conductive silver paste, realizing serial and parallel connection design of multilayer components by adopting a stacking process, and improving the design specification of a product, wherein the L TCC (cross resistance coefficient) device obtained by the method has better quality, and a fine circuit can be manufactured more easily.

The method for manufacturing the L TCC device can be applied to manufacturing of L TCC multilayer ceramic packaging substrates in large batch, can also be applied to process adjustment of test samples, and can be used for manufacturing independent L TCC passive devices and integrated functional devices by adopting the technical idea of the invention.

Drawings

FIG. 1 is a schematic diagram of a manufacturing technique for L TCC internal electrode interconnect circuitry according to the present invention, wherein A is masking, B is plating, C is removing masking, D is casting ceramic slurry, E is stripping green tile, 1 is masking, 2 is titanium substrate, 3 is copper line, 4 is ceramic slurry, 5 is green tile

FIG. 2 is a microscopic topography of conductive silver paste and electroplated copper lines. (a) SEM image of the circuit section of the silver paste sintered at 800 ℃; (b) SEM image of the circuit section of the silver paste sintered at 900 ℃; (c) SEM sectional view of the product manufactured in step 2) of the method of the invention; (d) the electroplated copper circuit SEM image and photoresist prepared by the method of the invention

Detailed Description

The present invention will be described in further detail with reference to specific embodiments, but it should not be construed that the scope of the subject matter of the present invention is limited to the examples.

The process equipment or devices not specifically noted in the following examples are conventional in the art; all reagents are commercially available.