A method for preparing a fully enclosed thin film integrated circuit and its application

Abstract

The present invention discloses a method for preparing a fully enclosed thin film integrated circuit and its application. The method comprises at least the following steps: (1) sputtering a film layer on the front and back sides of a ceramic substrate; (2) protecting the front side with a photoresist; (3) depositing a metal layer; (4) photolithographically etching a resistor; (5) sputtering a film layer on the front side of a ceramic thin film; (6) photolithographically etching the front side pattern and leads; (7) photolithographically covering the leads; and (8) fully enclosed chemical deposition. The fully enclosed thin film integrated circuit prepared in the present application has a good service life and side corrosion resistance, and effectively improves the line width accuracy of the integrated circuit. It is suitable for promotion in the field of integrated circuits and has broad development prospects.

Description

Technical Field

[0001] The present invention relates to a field, and in particular to a method for preparing a fully enclosed thin film integrated circuit and its application. Background Art

[0002] An integrated circuit (IC) is a small or micro electronic device or component that can be considered the smallest component required to implement a circuit's functionality. The main surface structure of an IC includes transistors, resistors, capacitors, inductors, and other components or patterns, connected by photolithographic wiring and encapsulated in a housing. The IC's base substrate can be a semiconductor wafer, ceramic diaphragm, or other material.

[0003] Ceramic diaphragm integrated circuits refer to circuits with special functions formed by integrating resistors, capacitors, inductors and microstrips on a specified ceramic dielectric substrate through sputtering, electroplating, etching and other related processes.

[0004] During production research, the applicant discovered that some ceramic thin film integrated circuits in the prior art have certain technical problems during use and preparation. For example, the prior art (CN201811492208.4) provides an integrated circuit board and a method for preparing the same, which claims to be able to effectively improve the shortcomings of the prior art and effectively improve the uniformity of the resistance distribution of the integrated circuit. However, the etching and corrosion treatments used in the preparation of its integrated circuits do not adopt obvious protective measures, which easily cause the side corrosion of the resistance graphics and lines, thereby damaging the quality of use and line width accuracy of the integrated circuit. For example, the prior art (CN201010554117) discloses a method for preparing a 99.6% alumina ceramic thin film substrate, which is mainly used for the composition of electronic devices, but the single-piece stacking sintering method it adopts requires too high a temperature and too long a time for the substrate to be sintered, reducing the production efficiency of the integrated circuit.

[0005] Therefore, in order to solve the above problems, the present invention applies for a fully enclosed ceramic thin film integrated circuit that can effectively prevent the occurrence of side corrosion, has higher reliability, and can make the line width accuracy of the product higher. The modified ceramic substrate used also effectively improves the axial working performance of the circuit while enhancing the production efficiency of the integrated circuit. Summary of the Invention

[0006] In order to solve the above problems, the first aspect of the present invention provides a method for preparing a fully enclosed thin film integrated circuit, which comprises at least the following steps: (1) sputtering a film layer on the front and back sides of a ceramic substrate; (2) protecting the front side with a photoresist; (3) depositing a metal layer; (4) photolithographic resistors; (5) sputtering a film layer on the front side of a ceramic thin film; (6) photolithographically etching the front side patterns and leads; (7) photolithographically covering the leads; and (8) fully enclosed chemical deposition.

[0007] As a preferred solution, the ceramic substrate is at least one of an alumina ceramic substrate, a mixed oxide ceramic substrate, and a nitride ceramic substrate.

[0008] As a preferred solution, the specific operation of sputtering the film layers on the front and back of the ceramic substrate is: sputtering a tantalum nitride film layer on the front of the ceramic substrate by magnetron sputtering, and sputtering a titanium tungsten, copper and gold composite film layer from the inside to the outside on the back of the ceramic substrate.

[0009] As a preferred solution, the thickness of the tantalum nitride film is 80-100 nm.

[0010] As a preferred solution, the thicknesses of the titanium-tungsten, copper and gold composite film layers are 30-50 nm, 0.3-0.5 μm and 0.2-0.3 μm respectively.

[0011] As a preferred solution, the specific operation of the photoresist front protection is: uniformly applying the photoresist on the surface of the ceramic substrate by means of coating, pre-baking, exposure, post-baking, development, and hardening.

[0012] As a preferred solution, the thickness of the photoresist is 4-5 μm.

[0013] As a preferred solution, the specific operation of depositing the metal layer is: depositing the metal layer on the reverse side of the ceramic substrate and in the hole by chemical vapor deposition.

[0014] As a preferred solution, the deposited metal of the deposited metal layer is titanium tungsten, copper and gold.

[0015] As a preferred solution, the thickness of the deposited metal layer is 2-3 μm, 0.5-1 μm, or 0.5-1 μm.

[0016] As a preferred solution, the specific operation of the photolithography resistor is: using the method of coating, pre-baking, exposure, post-baking, development, and hardening the film to make a resistor pattern on the front film layer, and then completely corroding the film layer outside the pattern with an etching solution.

[0017] As a preferred solution, the specific operation of sputtering the film layer on the front side of the ceramic film is: sputtering a titanium tungsten, copper and gold composite film layer on the front side of the ceramic film for the second time.

[0018] As a preferred solution, the specific operation of the photolithography front pattern and lead is: using the method of uniform coating, pre-baking, exposure, post-baking, development, and hardening the film to make the front pattern and lead on the front film layer, and then completely corroding the film layer outside the pattern and lead with an etching liquid.

[0019] As a preferred solution, the specific operation of the photolithography covering lead is: photolithography covering the lead by means of coating, pre-baking, exposure, post-baking, development, and hardening.

[0020] As a preferred solution, the specific operation of the fully enclosed chemical deposition is: using a chemical deposition method to deposit a metal gold layer on the front and side walls of the pattern, and then using an etching solution to completely corrode the leads.

[0021] As a preferred solution, the specific operation of the fully enclosed chemical deposition is: depositing the required metal layer on the surface of the ceramic substrate by a chemical vapor deposition method.

[0022] In the present invention, by adopting the method of full-surround chemical deposition, the side mis-etching phenomenon of the surface pattern in the integrated circuit during the etching process is effectively reduced, and the line width accuracy can be effectively improved, so that the minimum line width accuracy reaches ±1 micron, which greatly improves the service strength and life of the ceramic thin film integrated circuit and reduces the complexity of the preparation method.

[0023] As a preferred solution, the resistance film layer is tantalum nitride.

[0024] As a preferred solution, the front metal layer is titanium tungsten, copper and gold.

[0025] As a preferred solution, the etching solution is at least one of nitric acid, hydrochloric acid, sulfuric acid, and hydrofluoric acid.

[0026] As a more preferred solution, the corrosive liquid is nitric acid.

[0027] As a preferred solution, the ceramic substrate is a mixed oxide ceramic substrate.

[0028] As a preferred embodiment, the preparation method of the mixed oxide ceramic substrate of the present invention comprises at least the following steps: (1) adding alumina powder to an organic acid solution, heating to 60-80°C and stirring for 80-100 minutes, cooling to room temperature after stirring, filtering, washing with an organic solvent, and drying; (2) adding the dried mixed powder of alumina powder and titanium dioxide to a DMF solution for dispersion, then preparing a DMF solution containing succinic anhydride, 3-aminopropyltriethoxysilane and vinyltrimethoxysilane and adding dropwise, heating to 80-100°C and stirring the solution for reaction for 4-6 hours, and drying after the reaction is completed; (3) adding the dried mixed powder, yttrium oxide, isopropyl alcohol, ethyl acetate, and phosphate to a ball mill and ball milling for 6-10 hours. After the ball milling is completed, polyvinyl butyral, polyethylene glycol 800, alcohol ether and diol are added, and the ball milling is continued for 4 to 6 hours, and then vacuum stirred for 20 to 30 minutes to obtain a mixed slurry; (4) the mixed slurry is sent to a casting machine for casting; the cast green sheet is placed in a punching machine for stamping and adjusting the required size; (5) the green sheet is placed in a debinding furnace and debinded twice under nitrogen protection. The first debinding temperature is 500 to 600 ° C and kept warm for 40 to 60 minutes, and the second debinding temperature is 150 to 200 ° C and kept warm for 40 to 60 minutes, and the heating rate is 5 ° C / minute; (6) the green sheet after debinding is placed in a sintering furnace, and the sintering temperature is maintained at 1550 to 1580 ° C, and sintered for 6 to 8 hours, with a heating rate of 10 ° C / minute, and the product is obtained.

[0029] As a preferred solution, the mass ratio of the aluminum oxide powder to the titanium dioxide is 98-99.9:0.1-1.5.

[0030] As a preferred solution, the average particle size of the titanium dioxide is 5 to 50 nm.

[0031] As a more preferred solution, the average particle size of the titanium dioxide is 10 to 20 nm.

[0032] In this application, the addition of trace amounts of titanium dioxide and alumina powder, followed by mixed modification, effectively improves the overall mechanical strength of ceramic integrated circuits, while also providing extremely high insulation and pollution resistance. The applicant speculates that titanium dioxide, as a nanoparticle, can effectively connect the ceramic substrate after sintering. In particular, the modified titanium dioxide in this application exhibits excellent connectivity with alumina powder and forms fine microscopic pores in the substrate. When the integrated circuit is subjected to external stress, these fine pores can effectively convert the external stress into a silver crazing state. Furthermore, when the substrate is about to break, the titanium dioxide effectively increases the substrate's fracture limit through its strong connectivity with the alumina powder, thereby causing the generated microscopic cracks to return to a silver crazing state.

[0033] As a preferred solution, the mass ratio of the mixed powder to succinic anhydride, 3-aminopropyltriethoxysilane and vinyltrimethoxysilane is 1:5:5:1-3.

[0034] In this invention, the overall flatness and mechanical strength of the integrated circuit are effectively improved by modifying the mixed powder. The applicant speculates that: the invention effectively changes the high polarity and surface energy of the aluminum oxide powder surface through the modification process, reduces the concentrated agglomeration of aluminum oxide, and avoids the mixed powder from being effectively and stably dispersed in the slurry during grinding, thereby preventing the density from being uneven during the casting process; at the same time, during the joint modification process, the groups on the surface of the titanium oxide particles in the mixed powder are carboxylated, effectively improving its hydrogen bonding effect during the preparation of ceramic substrates, further reducing the overall polarity of the mixed powder and reducing the interaction between particles, thereby effectively enhancing the interfacial compatibility and wettability of the mixed powder during the sheeting process; the applicant further found that when the mass ratio of the mixed powder to succinic anhydride, 3-aminopropyltriethoxysilane and vinyltrimethoxysilane is 1:5:5:1-3, the overall strength of the integrated circuit reaches the best.

[0035] As a preferred solution, the mass ratio of the mixed powder, yttrium oxide, isopropyl alcohol, ethyl acetate, and phosphate is 1-1.5:0.01-0.05:1-2:0.1-0.8:0.01-0.1.

[0036] As a more preferred solution, the mass ratio of the mixed powder, yttrium oxide, isopropyl alcohol, ethyl acetate, and phosphate is 1-1.2: 0.02-0.04: 1-1.5: 0.3-0.6: 0.03-0.05.

[0037] As a preferred solution, the alcohol ether is at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, propylene glycol butyl ether, and propylene glycol methyl ether.

[0038] As a more preferred solution, the alcohol ether is diethylene glycol butyl ether.

[0039] As a preferred solution, the diol is at least one of ethylene glycol and propylene glycol.

[0040] As a preferred solution, the diol is propylene glycol.

[0041] As a preferred solution, the mass ratio of the mixed powder to polyvinyl butyral, polyethylene glycol 800, alcohol ether and diol is 1-1.5:0.05-0.15:0.05-0.1:0.01:0.01-0.05.

[0042] As a preferred solution, the mass ratio of the mixed powder to polyvinyl butyral, polyethylene glycol 800, alcohol ether and diol is 1-1.2:0.12:0.08:0.01:0.03.

[0043] A second aspect of the present invention provides an application of the above-mentioned method for preparing a fully enclosed thin film integrated circuit, including application of the method for preparing a fully enclosed thin film integrated circuit in an integrated circuit manufacturing process.

[0044] Beneficial effects:

[0045] 1. The fully enclosed ceramic integrated circuit prepared in the present invention application has an excellent corrosion sidewall protection effect, which can effectively protect the sidewalls of patterns or circuits during the preparation and production of integrated circuits, thereby preventing them from being accidentally etched during the corrosion or etching process, thereby effectively improving the use quality of the integrated circuit and effectively improving the line width accuracy of the product. The minimum line width accuracy can be controlled within ±1 micron.

[0046] 2. The fully enclosed ceramic integrated circuit in the present invention adopts a modified alumina ceramic substrate, which effectively improves the density, uniformity and mechanical strength of the ceramic substrate and effectively improves the overall strength of the ceramic integrated circuit.

[0047] 3. The method for preparing a fully enclosed ceramic integrated circuit proposed in the present invention proposes a method for preparing an integrated circuit with high performance and long service life, which can effectively promote the working efficiency and service life of the overall electronic components, thereby effectively improving the quality of electronic products, and has great social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is a schematic diagram of the surface film layer of the ceramic integrated circuit of this application.

[0049] Figure 2 Schematic diagram of the surface film layer of an ordinary ceramic integrated circuit.

[0050] In the figure: 1-gold metal layer, 2-copper metal layer, 3-titanium tungsten metal layer. DETAILED DESCRIPTION

[0051] The present invention can be more easily understood by referring to the following preferred embodiments of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs. In the event of a conflict, the definitions in this specification shall prevail.

[0052] Example

[0053] The technical solution of the present invention is described in detail below by way of examples, but the scope of protection of the present invention is not limited to all the examples described. Unless otherwise specified, the raw materials of the present invention are all commercially available.

[0054] Example 1

[0055] The first aspect of the embodiment 1 provides a method for preparing a fully enclosed thin film integrated circuit, which comprises at least the following steps: (1) sputtering a tantalum nitride film layer (the film thickness is 100 nm) on the front side of a ceramic substrate by magnetron sputtering, and sputtering a titanium tungsten, copper and gold composite film layer from the inside out on the back side of the ceramic substrate (the thickness of titanium tungsten, copper and gold are 40 nm, 0.4 μm and 0.3 μm respectively); (2) uniformly applying a photoresist (with a thickness of 4.5 μm) on the surface of the ceramic substrate by means of coating, pre-baking, exposure, post-baking, development and hardening; (3) depositing a metal layer of titanium tungsten, copper and gold (with a thickness of 2.5 μm, 1 μm and 1 μm respectively) on the back side of the ceramic substrate and in the hole by means of chemical vapor deposition; (4) coating, pre-baking, exposure, post-baking, development and hardening. , post-bake, develop, and harden the film to make a resistor pattern on the front film layer, and then completely etch the film layer outside the pattern with nitric acid etching solution; (5) sputter-plated titanium tungsten, copper and gold composite film layers on the front of the ceramic film for the second time (the thickness of titanium tungsten, copper and gold are 40nm, 0.4μm and 0.3μm respectively); (6) adopting the method of uniform coating, pre-bake, exposure, post-bake, develop, and harden the film to make the front pattern and lead on the front film layer, and then completely etch the film layer outside the pattern and lead with etching solution; (7) adopting the method of uniform coating, pre-bake, exposure, post-bake, develop, and harden the film to cover the lead with photolithography; (8) adopting the method of chemical deposition, depositing a metal gold layer (thickness is 0.3μm) on the front and side walls of the pattern, and then completely etching the lead with etching solution.

[0056] In this embodiment, the ceramic substrate is a mixed oxide ceramic substrate, and the preparation method comprises the following steps (in parts by weight): (1) adding 5 parts of alumina powder to 80 parts of a 5 wt% stearic acid ethanol solution, heating to 65° C. and stirring for 90 minutes, cooling to room temperature after stirring, filtering, washing with n-hexane, and drying; (2) adding 5 parts of a mixed powder of dried alumina powder and titanium dioxide (average particle size 15 nm) (the mass ratio of alumina to titanium dioxide is 99:1) to 100 parts of DMF solution for dispersion, and then preparing 150 parts of DMF solution containing 25 parts of succinic anhydride, 25 parts of 3-aminopropyltriethoxysilane and 10 parts of vinyltrimethoxysilane were added dropwise, and the temperature was raised to 90°C. The solution was stirred and reacted for 5 hours. After the reaction was completed, it was dried; (3) 1.1 parts of the dried mixed powder, 0.03 parts of yttrium oxide, 1.2 parts of isopropyl alcohol, 0.4 parts of ethyl acetate and 0.03 parts of phosphate were added to a ball mill and ball milled for 7 hours. After the ball milling was completed, 0.12 parts of polyvinyl butyral and 800 parts of polyethylene glycol were added. 0.08 parts of propylene glycol, 0.01 parts of diethylene glycol butyl ether and 0.03 parts of propylene glycol, continue ball milling for 5 hours, and then vacuum stir for 25 minutes to obtain a mixed slurry; (4) send the mixed slurry into a casting machine for casting; place the cast green sheet into a punching machine for stamping and adjust the required size; (5) place the green sheet into a debinding furnace and debind twice under nitrogen protection, the first debinding temperature is 600℃ and kept warm for 45 minutes, the second debinding temperature is 180 and kept warm for 55 minutes, and the heating rate is 5℃ / min; (6) place the green sheet after debinding into a sintering furnace, maintain the sintering temperature at 1565℃, sinter for 7.5 hours, and the heating rate is 10℃ / min to complete.

[0057] In this embodiment, the alumina powder is a 99.99% grade alumina powder product sold by Zhongnuo New Materials Co., Ltd.

[0058] In this embodiment, the titanium dioxide is a 5-20 nanometer grade titanium dioxide product sold by Aladdin Reagent Company.

[0059] In this embodiment, 3-aminopropyltriethoxysilane CAS: 919-30-2, succinic anhydride CAS: 108-30-5, and vinyltrimethoxysilane CAS: 2768-02-7.

[0060] In this embodiment, the yttrium oxide is a 99.99% grade yttrium oxide product sold by Aladdin Reagent Company.

[0061] In this embodiment, polyvinyl butyral is a polyvinyl butyral product sold by Shandong Haoshun Chemical Co., Ltd.

[0062] In this embodiment, polyethylene glycol 800 is the polyethylene glycol 800 product sold by Jiangsu Jiaren Chemical Co., Ltd.

[0063] Example 2

[0064] The specific implementation of this embodiment is the same as that of Example 1, except that the mass ratio of aluminum oxide to titanium dioxide is 99.5:0.5.

[0065] Example 3

[0066] The specific implementation of this embodiment is the same as that of Example 1, except that the amount of vinyltrimethoxysilane is 15 parts.

[0067] Comparative Example 1

[0068] The specific implementation of this comparative example is the same as that of Example 1, except that the mass ratio of aluminum oxide to titanium dioxide is 96.5:3.5.

[0069] Comparative Example 2

[0070] The specific implementation of this comparative example is the same as that of Example 1, except that the mixed powder of aluminum oxide and titanium dioxide does not undergo the modification step in step (2).

[0071] Comparative Example 3

[0072] The specific implementation of this comparative example is the same as that of Example 1, except that step (8) does not perform side gold metal deposition.

[0073] Performance evaluation

[0074] 1. Line width accuracy: The line width accuracy difference of the integrated circuits prepared in each embodiment and comparative example was observed by SEM electron microscope. Five samples were tested for each embodiment and comparative example, and the average value of the measured values was recorded in Table 1.

[0075] 2. Toughness Strength: The integrated circuits prepared in each embodiment and comparative example were tested for overall toughness strength using a thin film toughness tester. Five samples were tested for each embodiment and comparative example, and the average of the measured values is recorded in Table 1.

[0076] Table 1

[0077] Example Line width accuracy difference (± micron) Toughness strength (Mpa m1 / 2) Example 1 0.77 16.7 Example 2 0.81 15.9 Example 3 0.82 16.1 Comparative Example 1 0.94 11.4 Comparative Example 2 0.95 12.1 Comparative Example 3 1.84 9.8

[0078] As can be seen from Examples 1-3, Comparative Examples 1-3, and Table 1, the present invention provides a method for preparing a fully enclosed thin-film integrated circuit and its application. The resulting ceramic thin-film integrated circuit exhibits excellent service life, excellent side corrosion resistance, and effectively improves the line width precision of the integrated circuit. These integrated circuits are suitable for promotion in the integrated circuit field and have broad development prospects. Example 1 achieved the best performance index under optimal raw material ratios and manufacturing process factors.

Claims

1. A method for preparing a fully enclosed thin film integrated circuit, characterized in that: The steps include at least the following: (1) sputtering film layers on the front and back sides of the ceramic substrate; (2) photoresist protection on the front side; (3) metal layer deposition; (4) photolithography resistor; (5) sputtering film layers on the front side of the ceramic film; (6) photolithography of the front side pattern and leads; (7) photolithography covering the leads; (8) full-surround chemical deposition; the specific operation of the full-surround chemical deposition is: using the chemical deposition method to deposit a metal gold layer on the front and side walls of the pattern, and then using an etching solution to completely corrode the leads; The ceramic substrate is a mixed oxide ceramic substrate. The preparation method of the mixed oxide ceramic substrate comprises at least the following steps: 1) adding alumina powder to an organic acid solution, heating to 60-80° C. and stirring for 80-100 minutes, cooling to room temperature after stirring, filtering, washing with an organic solvent, and drying; 2) adding the dried mixed powder of alumina powder and titanium dioxide to a DMF solution for dispersion, then preparing a DMF solution containing succinic anhydride, 3-aminopropyltriethoxysilane, and vinyltrimethoxysilane and adding dropwise, heating to 80-100° C. and stirring the solution for reaction for 4-6 hours, and drying after the reaction is completed; 3) adding the dried mixed powder, yttrium oxide, isopropyl alcohol, ethyl acetate, and phosphate to a ball mill for ball milling for 6-10 hours, and then adding polyethylene glycol after the ball milling is completed. Enol butyral, polyethylene glycol 800, alcohol ether and diol are ball-milled for 4 to 6 hours, and then vacuum-stirred for 20 to 30 minutes to obtain a mixed slurry; 4) the mixed slurry is fed into a tape casting machine for tape casting; the tape-cast green sheet is placed in a sheet punching machine for punching and adjusting the required size; 5) the green sheet is placed in a debinding furnace and debinded twice under nitrogen protection, the first debinding temperature is 500 to 600°C and kept warm for 40 to 60 minutes, the second debinding temperature is 150 to 200°C and kept warm for 40 to 60 minutes, and the heating rate is 5°C / minute; 6) the debinding green sheet is placed in a sintering furnace, the sintering temperature is maintained at 1550 to 1580°C, sintered for 6 to 8 hours, and the heating rate is 10°C / minute to complete the process; the mass ratio of the alumina powder to the titanium dioxide is 98 to 99.9:0.1 to 1.

5.

2. The method for preparing a fully enclosed thin film integrated circuit according to claim 1, wherein: The specific operation of sputtering the film layers on the front and back sides of the ceramic substrate is: sputtering a tantalum nitride film layer on the front side of the ceramic substrate by magnetron sputtering, and sputtering a titanium tungsten, copper and gold composite film layer from the inside to the outside on the back side of the ceramic substrate.

3. The method for preparing a fully enclosed thin film integrated circuit according to claim 1, wherein: The specific operation of depositing the metal layer is: depositing the metal layer on the reverse side of the ceramic substrate and in the hole by chemical vapor deposition.

4. The method for preparing a fully enclosed thin film integrated circuit according to claim 1, wherein: The specific operation of the photolithography resistor is: using the method of coating, pre-baking, exposure, post-baking, development, and hardening the film to make a resistor pattern on the front film layer, and then completely corroding the film layer outside the pattern with an etching solution.

5. The method for preparing a fully enclosed thin film integrated circuit according to claim 1, wherein: The specific operation of the photolithography front pattern and lead is: using the method of coating, pre-baking, exposure, post-baking, development, and hardening the film to make the front pattern and lead on the front film layer, and then completely corroding the film layer outside the pattern and lead with an etching solution.

6. The method for preparing a fully enclosed thin film integrated circuit according to claim 1, wherein: The etching solution is at least one of nitric acid, hydrochloric acid, sulfuric acid and hydrofluoric acid.

7. An application of the method for preparing a fully enclosed thin film integrated circuit according to any one of claims 1 to 6, characterized in that: The invention also includes the application of the preparation method of the fully enclosed thin film integrated circuit in the integrated circuit preparation process.

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