CN114554706A - Alkaline etching method for fine circuit - Google Patents
Alkaline etching method for fine circuit Download PDFInfo
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- CN114554706A CN114554706A CN202210447491.9A CN202210447491A CN114554706A CN 114554706 A CN114554706 A CN 114554706A CN 202210447491 A CN202210447491 A CN 202210447491A CN 114554706 A CN114554706 A CN 114554706A
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- 238000005530 etching Methods 0.000 title claims abstract description 190
- 238000000034 method Methods 0.000 title claims abstract description 69
- 238000003825 pressing Methods 0.000 claims abstract description 72
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 56
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 34
- 235000011114 ammonium hydroxide Nutrition 0.000 claims abstract description 34
- 239000003814 drug Substances 0.000 claims abstract description 29
- 230000008569 process Effects 0.000 claims abstract description 29
- 238000009713 electroplating Methods 0.000 claims abstract description 8
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims abstract description 4
- 238000003475 lamination Methods 0.000 claims description 78
- 238000013507 mapping Methods 0.000 claims description 30
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 28
- 229910021529 ammonia Inorganic materials 0.000 claims description 9
- 239000007788 liquid Substances 0.000 claims description 4
- 206010010904 Convulsion Diseases 0.000 claims description 2
- 230000036461 convulsion Effects 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 13
- 238000006243 chemical reaction Methods 0.000 abstract description 12
- 238000004519 manufacturing process Methods 0.000 abstract description 8
- 230000008929 regeneration Effects 0.000 abstract description 8
- 238000011069 regeneration method Methods 0.000 abstract description 8
- 238000009423 ventilation Methods 0.000 abstract description 7
- 239000010949 copper Substances 0.000 description 15
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 12
- 238000012545 processing Methods 0.000 description 11
- 239000000853 adhesive Substances 0.000 description 9
- 230000001070 adhesive effect Effects 0.000 description 9
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 8
- 235000019270 ammonium chloride Nutrition 0.000 description 6
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 6
- 230000000536 complexating effect Effects 0.000 description 5
- 239000011889 copper foil Substances 0.000 description 5
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 5
- 238000002425 crystallisation Methods 0.000 description 5
- 230000008025 crystallization Effects 0.000 description 5
- 239000013589 supplement Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- LQBJWKCYZGMFEV-UHFFFAOYSA-N lead tin Chemical compound [Sn].[Pb] LQBJWKCYZGMFEV-UHFFFAOYSA-N 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 230000018109 developmental process Effects 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 230000009469 supplementation Effects 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- 229910021592 Copper(II) chloride Inorganic materials 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 230000001502 supplementing effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 229960003280 cupric chloride Drugs 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 238000010979 pH adjustment Methods 0.000 description 1
- 150000003071 polychlorinated biphenyls Chemical class 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
- H05K3/06—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed chemically or electrolytically, e.g. by photo-etch process
- H05K3/068—Apparatus for etching printed circuits
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
- H05K3/06—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed chemically or electrolytically, e.g. by photo-etch process
- H05K3/067—Etchants
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Microelectronics & Electronic Packaging (AREA)
- ing And Chemical Polishing (AREA)
- Manufacturing Of Printed Circuit Boards (AREA)
Abstract
The application relates to a fine line alkaline etching method. The method comprises the following steps: sequentially carrying out film pressing treatment, exposure treatment, positive developing treatment, pattern electroplating treatment and film stripping treatment on the copper-clad plate to obtain a circuit board to be etched; adjusting the pH value of the alkaline etching agent to be between 8.8 and 9.2 by using ammonia water; adjusting the opening degree of an exhaust valve of the etching machine based on the pH value of the alkaline etching agent; and (3) carrying out alkaline etching treatment on the circuit board to be etched by using an etching machine and an alkaline etching agent, and then stripping tin to obtain the target circuit board. The utility model provides a scheme can be according to the ventilation valve aperture of the pH value adaptability adjustment etching machine of alkaline etching medicament to the performance that the operating parameter that makes the etching machine matches the alkaline etching medicament makes the alkaline etching process guarantee the stable emergence of regeneration reaction under the condition that maintains alkaline etching medicament pH value, reaches a balanced state, thereby ensures the etching effect and the production security of circuit.
Description
Technical Field
The application relates to the technical field of PCBs, in particular to an alkaline etching method for fine lines.
Background
With the large-scale integration development of chips, electronic products are also gradually densified and highly intelligentized, and printed circuit boards serving as component supports and electric signal transmission carriers are gradually miniaturized, light-weighted, high-density and multifunctional, so that higher requirements are provided for manufacturing blind holes and fine circuits of circuit boards. The requirement on the fineness of the circuits on the circuit board is higher and higher, and the requirement on the processing technology of the fine circuits is also improved.
In the traditional alkaline etching process, copper is continuously dissolved along with the operation of an etching line, the specific gravity of the solution is continuously increased, and when the specific gravity exceeds a certain value, the automatic control system automatically supplements the alkaline etching solution of an ammonium chloride and ammonia water system to enable the specific gravity of the solution to be in a proper range. Therefore, in order to ensure the quality of alkaline etching, ammonia and ammonium chloride need to be continuously added into the chemical solution during etching. In the process, ammonia water plays a complexing role, the strength of the complexing role is reflected by the PH value of an alkaline etching agent, for the etching process of fine lines, the supplement of the ammonia water and ammonium chloride needs to be carefully controlled, and when the supplement of the ammonia water and the ammonium chloride is excessive or insufficient, the complexing effect of the alkaline etching agent is poor, so that the problem of line edge undercut of a circuit board occurs, and the circuit board is unqualified; even crystallization can be generated to influence the operation of the motor and the production safety.
The existing automatic control system for automatically supplementing ammonium chloride and ammonia water generally controls the ammonia water supplementation and the working parameters of an etching machine based on a fixed value preset by production personnel, and environmental change in the alkaline etching process can also influence the alkaline etching process, so that the problem that the working of the etching machine participates in the performance mismatch of medicaments is easy to occur when the ammonia water is supplemented and the etching machine is controlled to work at the fixed value, the complexing effect of the alkaline etching medicaments is still easy to be poor, the problem of line-edge undercut of a circuit board is caused, the problem of line open circuit notch and the problem of crystallization are caused.
Disclosure of Invention
In order to overcome the problems in the related art, the present application provides a method for fine line alkaline etching, which can ensure the stable occurrence of regeneration reaction while maintaining the PH of an alkaline etching agent, thereby ensuring the etching effect and production safety of the line.
The application provides a fine line alkaline etching method, which comprises the following steps:
sequentially carrying out film pressing treatment, exposure treatment, positive developing treatment, pattern electroplating treatment and film stripping treatment on the copper-clad plate to obtain a circuit board to be etched;
adjusting the pH value of the alkaline etching agent to be between 8.8 and 9.2 by using ammonia water;
based on the pH value adjustment etching machine's of alkaline etching medicament convulsions valve aperture specifically includes: when the PH value of the alkaline etching agent is equal to 9-0.04a, adjusting the opening degree of the exhaust valve to be equal to V degrees, wherein V = 30-a; the range of the opening degree of the exhaust valve is 25-35 degrees; a is a conversion factor and is used for grading the PH value of the alkaline etching agent and the opening degree of the exhaust valve;
and carrying out alkaline etching treatment on the circuit board to be etched by using the etching machine and the alkaline etching agent, and then carrying out tin stripping treatment to obtain the target circuit board.
In one embodiment, the lamination process includes:
determining the film pressing speed according to the film pressing pressure;
and pressing the film based on the film pressing pressure and the film pressing speed.
In one embodiment, the determining the lamination speed according to the lamination pressure comprises:
when the difference value delta P between the lamination pressure and the lamination pressure reference value is a positive number and meets the condition that the delta P is more than or equal to threshold _2, the lamination speed is adjusted to be 1.6 m/min to 2.2 m/min;
when the difference value delta P between the lamination pressure and the lamination pressure reference value is a positive number and meets the condition that the difference value delta P is more than or equal to threshold _1 and less than threshold _2, the lamination speed is adjusted to be 2.2 m/min;
when the difference value delta P between the lamination pressure and the lamination pressure reference value is a negative number, the lamination speed is adjusted to be
；
The threshold _1 represents a first threshold; the threshold _2 represents a second threshold; the first threshold is less than a second threshold; the reference value of the squeeze film pressure is 5kg/cm2。
In one embodiment, before the adjusting the PH of the alkaline etchant with ammonia to between 8.8 and 9.2, the method includes:
determining the PH value of the alkaline etching agent according to the film pressing speed, the film pressing speed weight, the film pressing pressure and the film pressing pressure weight; wherein the squeeze film speed weight is less than the squeeze film pressure weight.
In one embodiment, the determining the PH of the alkaline etchant according to the lamination speed, the lamination speed weight, the lamination pressure, and the lamination pressure weight comprises:
determining a speed mapping PH value in a preset mapping table according to the film pressing speed;
determining a pressure mapping PH value in a preset mapping table according to the film pressing pressure;
determining the pH value of the alkaline etching agent according to the following formula by combining the speed mapping pH value, the pressure mapping pH value, the squeeze film speed weight and the squeeze film pressure weight:
PH=PH_1*w1+ PH_2*w2；
wherein PH represents the PH value of the alkaline etching agent, and PH _1 represents the PH value of the speed map; PH _2 represents a pressure map PH value; w1 denotes the squeeze film velocity weight; w2 denotes squeeze film pressure weight; the preset mapping table stores the one-to-one correspondence relationship between the film pressing speed and the speed mapping PH value and the one-to-one correspondence relationship between the film pressing pressure and the pressure mapping PH value.
In one embodiment, the adjusting the PH of the alkaline etchant with ammonia to between 8.8 and 9.2 includes:
gradually adding ammonia water with preset concentration into the alkaline etching liquid medicine according to a preset adding proportion until the PH value of the alkaline etching liquid medicine is between 8.8 and 9.2;
wherein the preset adding proportion is 0.8-1.2%; the preset concentration is 5% -20%.
In one embodiment, in the exposure process, the exposure energy is controlled to 6 to 8 grids based on an exposure scale;
in the positive developing treatment, the developing point is controlled to be 40-60%.
In one embodiment, the line width of the target circuit board is less than or equal to 3 mils, and the pitch of the target circuit board is less than or equal to 3 mils.
The technical scheme provided by the application can comprise the following beneficial effects:
the application provides a meticulous circuit alkaline etching method, it obtains the circuit board of treating that is printed with the circuit figure through press mold processing, exposure processing, positive film development processing, figure electroplating processing and the processing of moving back membrane, because alkaline etching process adds the aqueous ammonia in the copper chloride solution, takes place the complex reaction: CuCl2+4NH3→Cu(NH3)4Cl2While the copper on the substrate is coated with [ Cu (NH)3)4]2+Oxidation, etching reaction occurs: cu (NH)3)4Cl2+Cu→2Cu(NH3)2Cl, [ Cu (NH) formed3)2] 1+Has no etching ability, and can be quickly oxidized by oxygen in the air only in the presence of excessive ammonia water and chloride ions to regenerate [ Cu (NH) having etching ability3)4]2+The regeneration reaction has the following chemical formula: 2Cu (NH)3)2Cl+2NH4Cl+2NH3+1/2O2→2Cu(NH3)4Cl+H2O, in the process, an exhaust valve needs to be opened to supplement air to the etching machine so as to ensure the stability of the regeneration reaction, but because ammonia has volatility, ammonia molecules are diffused to the periphery without stopping moving and are diffused outwards through the opened exhaust valve, so that [ Cu (NH) in the alkaline etching agent3)4]2+The content decline, the PH value that leads to alkaline etching medicament is crossed lowly, produces the crystallization and influences the complex effect simultaneously, and influences the performance of alkaline etching medicament, consequently, this application when utilizing the aqueous ammonia to adjust the PH value of alkaline etching medicament, according to the exhaust valve aperture of the PH value adaptability adjustment etching machine of alkaline etching medicament to the performance of the operating parameter matching alkaline etching medicament of messenger's etching machine specifically includes: with PH =9 as the benchmark, when the PH value is less than 9, the alkalinity of the alkaline etching agent is weakened, namely the volatilization speed of the ammonia water is faster or the volatilization amount of the ammonia water is larger, at the moment, the opening of the exhaust valve is adaptively reduced so as to slow down the volatilization of the ammonia water and maintain the PH value of the alkaline etching agent. Of alkaline etching agents by conversion factor aThe PH value and the opening degree of the exhaust valve are graded, the graded PH value and the opening degree of the exhaust valve are in one-to-one correspondence, so that the opening degree of the exhaust valve is adjusted, the alkaline etching process guarantees the stable generation of the regeneration reaction under the condition of maintaining the PH value of the alkaline etching agent, a balance state is achieved, and the etching effect and the production safety of the circuit are guaranteed.
In addition, among traditional alkaline etching process, the updraft ventilator valve aperture in the etching machine sets up to 90, and in this application, in order to guarantee the etching quality of meticulous circuit, the etching will not lead to the mutual adhesion of circuit to lead to the short circuit, consequently, sets up the adjustment benchmark of updraft ventilator valve aperture to 30 in this application, preferentially guarantees the stability of alkaline etching medicament pH value to guarantee the performance of alkaline etching medicament.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.
Drawings
The foregoing and other objects, features and advantages of the application will be apparent from the following more particular descriptions of exemplary embodiments of the application, as illustrated in the accompanying drawings wherein like reference numbers generally represent like parts throughout the exemplary embodiments of the application.
FIG. 1 is a schematic flow chart of a fine line alkaline etching method according to an embodiment of the present application;
fig. 2 is a schematic flow chart of a method for adjusting the opening of an exhaust valve according to an embodiment of the present disclosure;
fig. 3 is a schematic flow chart of a lamination process according to an embodiment of the present disclosure;
fig. 4 is a flowchart illustrating a method for adjusting the PH of the alkaline etchant according to an embodiment of the present disclosure.
Detailed Description
Preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While the preferred embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.
It should be understood that although the terms "first," "second," "third," etc. may be used herein to describe various information, these information should not be limited to these terms. These terms are only used to distinguish one type of information from another. For example, first information may also be referred to as second information, and similarly, second information may also be referred to as first information, without departing from the scope of the present application. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
Example one
The existing automatic control system for automatically supplementing ammonium chloride and ammonia water generally controls the ammonia water supplementation and the working parameters of an etching machine based on a fixed value preset by production personnel, the problem that the working of the etching machine participates in the performance mismatch easily occurs when the ammonia water supplementation and the working of the etching machine are controlled by the fixed value, and the problem of line edge undercut and crystallization of a circuit board are caused due to the poor complexing effect of an alkaline etching agent still easily occurs.
In view of the above problems, embodiments of the present application provide a method for fine line alkaline etching.
The technical solutions of the embodiments of the present application are described in detail below with reference to the accompanying drawings.
Fig. 1 is a schematic flow chart of a fine line alkaline etching method shown in an embodiment of the present application.
Referring to fig. 1, the fine line alkaline etching method includes:
101. sequentially carrying out film pressing treatment, exposure treatment, positive developing treatment, pattern electroplating treatment and film stripping treatment on the copper-clad plate to obtain a circuit board to be etched;
in the embodiment of the application, after the film pressing treatment, the exposure treatment, the positive developing treatment, the graphic electroplating treatment and the film stripping treatment, the area of the circuit on the copper-clad plate is covered by the dry film and the tin-lead layer, the copper foil of the area except the circuit is exposed, and the tin-lead layer cannot react with the alkaline etching agent in the subsequent alkaline etching process, so that the copper foil of the circuit area after alkaline etching is reserved, and the copper foil of the area except the circuit is etched and removed by the alkaline etching agent.
Further, in the exposure treatment, the exposure energy is controlled to be 6-8 grids based on an exposure ruler; in the positive developing treatment, the developing point is controlled to be 40-60%.
102. Adjusting the pH value of the alkaline etching agent to be between 8.8 and 9.2 by using ammonia water;
in the embodiment of the application, ammonia water with a preset concentration can be added into the alkaline etching solution in a preset adding proportion until the pH value of the alkaline etching solution is between 8.8 and 9.2; in the embodiment of the application, the preset adding proportion is 0.8% -1.2%; the preset concentration is 5% -20%.
Preferably, the preset adding proportion is 1%; the preset concentration is 10%.
Or a mode combining coarse adjustment and fine adjustment is adopted, for example, firstly, the ammonia water is supplemented in an adding proportion of 2% until the pH value of the alkaline etching reagent is above 8, and then the ammonia water is supplemented in an adding proportion of 1% until the pH value of the alkaline etching reagent is between 8.8 and 9.2.
It should be noted that the above description of the PH adjustment manner of the alkaline etchant is only an example given in the embodiments of the present application, and is not necessarily the only limitation of the present application.
103. Adjusting the opening degree of an exhaust valve of the etching machine based on the pH value of the alkaline etching agent;
in the traditional alkaline etching process, the opening degree of an exhaust valve of an etching machine is usually set to be 90 degrees; and in this application embodiment, the ventilation valve aperture of etching machine adjusts according to the pH value of the interior alkaline etching medicament of etching machine, specifically, can carry out dynamic adjustment by automatic control system real-time supervision alkaline etching medicament's pH value to ventilation valve aperture, can also set up fixed adjustment cycle, detects and adjusts ventilation valve aperture according to the pH value of current alkaline etching medicament the pH value of alkaline etching medicament at adjustment cycle node.
Specifically, the method for adjusting the opening degree of the exhaust valve of the etching machine provided by the embodiment of the application comprises the following steps: in the method, the value range of the opening degree of an air draft valve is 25-35 degrees, when the PH value of the alkaline etching agent is equal to 9-0.04a, the opening degree of the air draft valve is adjusted to be equal to V degrees, wherein V = 30-a; and a is a conversion factor and is used for grading the PH value of the alkaline etching agent and the opening degree of the exhaust valve.
Referring to fig. 2, the specific steps for adjusting the opening of the exhaust valve are as follows:
201. according to the formula: calculating the value of a conversion factor a by PH =9-0.04 a;
wherein, PH represents the PH value of the alkaline etching agent;
202. combining the formula according to the conversion factor a: v =30-a adjusting the suction fan valve;
wherein V is equal to the angle value of the opening degree of the exhaust valve.
It should be noted that the above description of the damper opening adjustment process is an example given in the embodiments of the present application, and is not necessarily taken as the only limitation of the present application.
104. And carrying out alkaline etching treatment on the circuit board to be etched by using the etching machine and the alkaline etching agent, and then carrying out tin stripping treatment to obtain the target circuit board.
And after the pH value of the alkaline etching agent and the opening of the exhaust valve are adjusted, feeding the circuit board to be etched into an etching machine, soaking, splashing or spraying the circuit board to be etched by using the alkaline etching agent to ensure that the exposed copper foil reacts with the alkaline etching agent to fall off, washing and drying, and removing the tin-lead layer covered on the circuit by using the tin-stripping agent to obtain the target circuit board.
Further, the line width of the target circuit board in the embodiment of the present application is less than or equal to 3mil, and the pitch of the lines is less than or equal to 3 mil.
The application provides a meticulous circuit alkaline etching method, it obtains the circuit board of treating etching that is printed with the circuit figure through press mold processing, exposure processing, positive film development processing, figure electroplating processing and the processing of moving back the membrane, because alkaline etching process adds the aqueous ammonia in the cupric chloride solution, takes place the complex reaction: CuCl2+4NH3→Cu(NH3)4Cl2While the copper on the substrate is coated with [ Cu (NH)3)4]2+Oxidation, etching reaction occurs: cu (NH)3)4Cl2+Cu→2Cu(NH3)2Cl, [ Cu (NH) formed3)2] 1+Has no etching ability, and can be quickly oxidized by oxygen in the air only in the presence of excessive ammonia water and chloride ions to regenerate [ Cu (NH) having etching ability3)4]2+The regeneration reaction has the following chemical formula: 2Cu (NH)3)2Cl+2NH4Cl+2NH3+1/2O2→2Cu(NH3)4Cl+H2O, in the process, an exhaust valve needs to be opened to supplement air to the etching machine so as to ensure the stability of the regeneration reaction, but because ammonia has volatility, ammonia molecules are diffused to the periphery without stopping moving and are diffused outwards through the opened exhaust valve, so that [ Cu (NH) in the alkaline etching agent3)4]2+The content decline, the PH value that leads to alkaline etching medicament is crossed lowly, produces the crystallization and influences the complex effect simultaneously, and influences the performance of alkaline etching medicament, consequently, this application when utilizing the aqueous ammonia to adjust the PH value of alkaline etching medicament, according to the exhaust valve aperture of the PH value adaptability adjustment etching machine of alkaline etching medicament to the performance of the operating parameter matching alkaline etching medicament of messenger's etching machine specifically includes: when the PH value is lower than 9 based on PH =9, the alkalinity of the alkaline etching agent is weakened, namely the ammonia water is volatilized faster or the ammonia water is volatilized more, and at the moment, the exhaust valve is adaptively adjustedThe opening is reduced to slow down the volatilization of ammonia water and maintain the pH value of the alkaline etching solution. The PH value and the ventilation valve opening degree of the alkaline etching agent are graded through the conversion factor a, the graded PH value and the ventilation valve opening degree are in one-to-one correspondence, so that the ventilation valve opening degree is adjusted, the alkaline etching process guarantees the stable occurrence of the regeneration reaction under the condition of maintaining the PH value of the alkaline etching agent, a balance state is achieved, and the etching effect and the production safety of the circuit are guaranteed.
In addition, among traditional alkaline etching process, the updraft ventilator valve aperture in the etching machine sets up to 90, and in this application, in order to guarantee the etching quality of meticulous circuit, the etching will not lead to the mutual adhesion of circuit to lead to the short circuit, consequently, sets up the adjustment benchmark of updraft ventilator valve aperture to 30 in this application, preferentially guarantees the stability of alkaline etching medicament pH value to guarantee the performance of alkaline etching medicament.
Example two
Based on the fine circuit alkaline etching method shown in the first embodiment, the present application provides another fine circuit alkaline etching method, where the exposure treatment, the positive developing treatment, the pattern electroplating treatment, the film stripping treatment, the PH value adjusting process of the alkaline etching agent, and the alkaline etching treatment in the fine circuit alkaline etching method are the same as those in the first embodiment, and are not described herein again.
The difference between the alkaline etching method for fine lines provided in the embodiments of the present application and the first embodiment is that, referring to fig. 3, the squeeze film process in the embodiments of the present application includes:
301. determining the film pressing speed according to the film pressing pressure;
the following are exemplary:
when the difference value delta P between the lamination pressure and the lamination pressure reference value is a positive number and meets the condition that the delta P is more than or equal to threshold _2, the lamination speed is adjusted to be 1.6 m/min to 2.2 m/min;
when the difference value delta P between the lamination pressure and the lamination pressure reference value is a positive number and meets the condition that the difference value delta P is more than or equal to threshold _1 and less than threshold _2, the lamination speed is adjusted to be 2.2 m/min;
when the difference value delta P between the lamination pressure and the lamination pressure reference value is a negative number, the lamination speed is adjusted to be
；
The difference value of the lamination pressure and the lamination pressure reference value is a numerical result obtained by subtracting the lamination pressure reference value from the lamination pressure; the threshold _1 represents a first threshold; the threshold _2 represents a second threshold; the first threshold is less than a second threshold; the reference value of the squeeze film pressure is 5kg/cm2。
In the embodiment of the application, a reference value of lamination pressure is used as a reference, the range of lamination pressure is divided into three sections, and different adjustment strategies are executed on lamination speed according to the actual interval where the lamination pressure is located:
when the difference value delta P is higher than the second threshold value, the current lamination pressure exceeds the lamination pressure reference value by a larger amplitude, namely the current lamination pressure level is at a higher level, and under the condition, the adhesive force of the dry film after lamination can be ensured, so that the limitation on the lamination speed in the aspect of the adhesive force is reduced, and the adjustment of the lamination speed is more flexible; meanwhile, in order to prevent dry film wrinkling, the film pressing speed can be adaptively reduced, but the film pressing speed cannot be matched with the flow speed of the film due to too low speed, so that the adjustment range of the film pressing speed has a lower limit, namely the lowest film pressing speed, which is 1.6 m/min in the embodiment of the application, and in the above case, the film pressing speed can be set to any speed between 1.6 m/min and 2.2 m/min;
when the difference value delta P is between the first threshold value and the second threshold value, the current lamination pressure is slightly higher than a lamination pressure reference value, namely the current lamination pressure is in a conventional lamination pressure value interval, a conventional lamination speed value is adaptively selected to be 2.2m/min, and the adhesive force and the lamination effect of the dry film are ensured through the cooperation of the lamination pressure and the lamination speed;
when difference delta P is the negative value, it has been less than press mold pressure reference value to explain current press mold pressure, and this moment, press mold effect receives press mold pressure's influence great, requires press mold speed and press mold pressure to strictly match in order to compensate the negative effects that press mold pressure is not enough to cause, consequently, according to press mold pressure adjustment press mold speed, concrete adjustment mode is:
wherein,
the lamination speed is indicated.
In the case where the above difference Δ P is a negative value, the lamination pressure is 0.5 kg/cm per time lower than the reference lamination pressure2And correspondingly adjusting the film pressing speed to be 0.01m/min up and down on the basis of 2.5 m/min to maintain the dry film adhesive force after film pressing, wherein in the subsequent alkaline etching process, the dry film adhesive force is too low to possibly cause the dry film to fall off, the circuit area is etched, and the consequence caused by the dry film falling off is more serious compared with the influence of the unevenness of the dry film surface on the etching quality, so when the difference value delta P is a negative value, the dry film adhesive force is preferentially considered to be improved, namely, the film pressing speed is adjusted according to the adjusting mode.
302. And pressing the film based on the film pressing pressure and the film pressing speed.
The embodiment of the application provides a fine line alkaline etching method, in the film pressing process, the film pressing speed is adjusted based on the film pressing pressure, the film pressing pressure is segmented according to a film pressing pressure reference value, different adjustment strategies are set for the film pressing pressures in different segments to determine the film pressing speed, the film pressing performance of the film pressing pressures in different segments is adaptively matched, film pressing influence caused by the film pressing pressures in different segments is compensated or utilized, the effect of the film pressing process is ensured, the adhesive force of a dry film is maintained, the dry film after film pressing is prevented from wrinkling, the conventional film pressing working parameters are also matched, and the film pressing working parameters are prevented from being greatly changed.
EXAMPLE III
Based on the method shown in any one of the first to second embodiments, in the embodiments of the present application, before the PH value of the alkaline etchant is adjusted to be between 8.8 and 9.2 by using the ammonia water, the PH value of the alkaline etchant is determined according to the squeeze film speed, the squeeze film speed weight, the squeeze film pressure, and the squeeze film pressure weight, so that the performance of the alkaline etchant is matched with the adhesion force of the dry film and the tin-lead layer on the circuit, and the covered dry film is prevented from falling off due to the fact that the covered dry film cannot bear the attack of the alkaline etchant when the adhesion force is low.
Specifically, in the embodiments of the present application, referring to fig. 4, the PH of the alkaline etchant is adjusted as follows:
401. determining a speed mapping PH value in a preset mapping table according to the film pressing speed;
402. determining a pressure mapping PH value in a preset mapping table according to the film pressing pressure;
in the embodiment of the application, the preset mapping table stores a one-to-one correspondence relationship between the film pressing speed and the speed mapping PH value and a one-to-one correspondence relationship between the film pressing pressure and the pressure mapping PH value; the method comprises the steps that a preset mapping table is stored in an etching machine control system in advance, when an ammonia water replenishing process is executed, the preset mapping table is called, after a speed mapping PH value and a pressure mapping PH value are searched, the corresponding PH value of an alkaline etching agent under the current condition is calculated.
It should be noted that, in the embodiment of the present application, the execution timing of step 401 and step 402 is not strictly limited, and in an actual application process, step 402 may be executed before step 401 or in parallel with both.
It is to be understood that the execution sequence of steps 401 and 402 is not the only limitation of the present application.
403. Determining the pH value of the alkaline etching agent according to a formula by combining a speed mapping pH value, a pressure mapping pH value, a lamination speed weight and a lamination pressure weight:
PH=PH_1*w1+ PH_2*w2；
wherein PH represents the PH value of the alkaline etching agent, and PH _1 represents the PH value of the speed map; PH _2 represents a pressure map PH value; w1 denotes the squeeze film velocity weight; w2 denotes squeeze film pressure weight; the squeeze film speed weight is less than the squeeze film pressure weight.
In the embodiment of the application, the film pressing pressure and the film pressing speed play a key role in the adhesion effect of the dry film, the dry film adhesion is poor, the dry film is easy to be attacked by the alkaline etching agent in the etching process, the dry film is caused to fall off in advance, the protection of the circuit area is eliminated, the copper foil of the circuit area which is not etched falls off, and the circuit is caused to be open, so that when the adhesion of the dry film is not enough to resist the attack of the alkaline etching agent, the attack force of the alkaline etching agent needs to be adjusted, namely, the PH value adaptability of the alkaline etching agent is reduced, and the alkaline etching agent is deflected to be neutral, so that the attack to the dry film is weakened.
During lamination, the lamination pressure bears a larger portion of the adhesion requirement than the lamination speed, so the lamination pressure is weighted higher than the lamination speed in the influence of the dry film adhesion, and thus the lamination pressure is set higher than the lamination speed in step 403.
The embodiment of the application provides a method for adjusting the pH value of an alkaline etching agent, the method finds the pH values corresponding to the current film pressing speed and the current film pressing pressure according to a preset mapping table, different weights are set for the film pressing speed and the film pressing pressure, the pH values corresponding to the film pressing speed and the film pressing pressure are combined with the weights of differences, the pH value after weight distribution is calculated, the performance of the alkaline etching agent is adjusted to the dry film adhesion condition after the film pressing treatment, the problem that the dry film cannot bear the attack of the alkaline etching agent and fall off is solved, and the circuit etching effect is further guaranteed.
Further, based on the method of the opening degree of the exhaust valve in the first embodiment, in combination with the squeeze film speed adjustment strategy in the second embodiment and the method of adjusting the PH value of the alkaline etching agent in the third embodiment, the obtained fine line alkaline etching method controls the adhesive force and squeeze film effect of the dry film in the squeeze film treatment stage, ensures the quality of squeeze film by adjusting the squeeze film speed according to the squeeze film pressure, and then determines the PH value of the alkaline etching agent adapted to the current squeeze film quality by taking different weights as calculation parameters of the PH value according to the difference of the influence degree of the squeeze film pressure and the squeeze film speed on the adhesive force of the dry film in the alkaline etching link, so as to ensure that the dry film does not fall off to cause open circuit in the alkaline etching, and line adhesion due to incomplete etching is avoided, and the opening degree of the exhaust valve of the etching machine is also adjusted according to the determined PH value, after the reference value is adjusted to 30 degrees from the original 90 degrees, the dynamic adjustment is carried out according to the PH value of the alkaline etching agent on the adjustment reference of 30 degrees, the sufficient oxygen is ensured, the phenomenon that the ammonia water is excessively volatilized to influence the etching quality is prevented, the etching of a fine circuit is accurately controlled, and the etching quality of the fine circuit is ensured.
The aspects of the present application have been described in detail hereinabove with reference to the accompanying drawings. In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to the related descriptions of other embodiments. Those skilled in the art should also appreciate that the acts and modules referred to in the specification are not necessarily required in the present application. In addition, it can be understood that the steps in the method of the embodiment of the present application may be sequentially adjusted, combined, and deleted according to actual needs, and the modules in the device of the embodiment of the present application may be combined, divided, and deleted according to actual needs.
Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the applications disclosed herein may be implemented as electronic hardware, computer software, or combinations of both.
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems and methods according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
The foregoing description of the embodiments of the present application has been presented for purposes of illustration and description and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen in order to best explain the principles of the embodiments, the practical application, or improvements made to the technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
Claims (8)
1. A method of fine line alkaline etching, comprising:
sequentially carrying out film pressing treatment, exposure treatment, positive developing treatment, pattern electroplating treatment and film stripping treatment on the copper-clad plate to obtain a circuit board to be etched;
adjusting the pH value of the alkaline etching agent to be between 8.8 and 9.2 by using ammonia water;
based on the pH value adjustment etching machine's of alkaline etching medicament convulsions valve aperture specifically includes: when the PH value of the alkaline etching agent is equal to 9-0.04a, adjusting the opening degree of the exhaust valve to be equal to V degrees, wherein V = 30-a; the range of the opening degree of the exhaust valve is 25-35 degrees; a is a conversion factor and is used for grading the PH value of the alkaline etching agent and the opening degree of the exhaust valve;
and carrying out alkaline etching treatment on the circuit board to be etched by using the etching machine and the alkaline etching agent, and then carrying out tin stripping treatment to obtain the target circuit board.
2. The fine line alkaline etching method as claimed in claim 1, wherein the lamination process comprises:
determining the film pressing speed according to the film pressing pressure;
and pressing the film based on the film pressing pressure and the film pressing speed.
3. The fine line alkaline etching method as claimed in claim 2, wherein said determining a lamination speed from a lamination pressure comprises:
when the difference value delta P between the lamination pressure and the lamination pressure reference value is a positive number and meets the condition that the delta P is more than or equal to threshold _2, the lamination speed is adjusted to be 1.6 m/min to 2.2 m/min;
when the difference value delta P between the lamination pressure and the lamination pressure reference value is a positive number and meets the condition that the difference value delta P is more than or equal to threshold _1 and less than threshold _2, the lamination speed is adjusted to be 2.2 m/min;
when the difference value delta P between the lamination pressure and the lamination pressure reference value is a negative number, the lamination speed is adjusted to be
；
The threshold _1 represents a first threshold; the threshold _2 represents a second threshold; the first threshold is less than a second threshold; the reference value of the squeeze film pressure is 5kg/cm2。
4. The method of claim 1, wherein the adjusting the PH of the alkaline etchant to between 8.8 and 9.2 with ammonia comprises:
determining the PH value of the alkaline etching agent according to the film pressing speed, the film pressing speed weight, the film pressing pressure and the film pressing pressure weight; wherein the squeeze film speed weight is less than the squeeze film pressure weight.
5. The fine line alkaline etching method of claim 4, wherein said determining the pH of the alkaline etchant according to the lamination speed, the lamination speed weight, the lamination pressure and the lamination pressure weight comprises:
determining a speed mapping PH value in a preset mapping table according to the film pressing speed;
determining a pressure mapping PH value in a preset mapping table according to the film pressing pressure;
determining the PH of the alkaline etchant according to the following equation in combination with the speed map PH, the pressure map PH, the lamination speed weight, and the lamination pressure weight:
PH=PH_1*w1+ PH_2*w2；
wherein PH represents the PH value of the alkaline etching agent, and PH _1 represents the PH value of the speed map; PH _2 represents a pressure map PH value; w1 denotes the squeeze film velocity weight; w2 denotes squeeze film pressure weight; the preset mapping table stores the one-to-one correspondence relationship between the film pressing speed and the speed mapping PH value and the one-to-one correspondence relationship between the film pressing pressure and the pressure mapping PH value.
6. The method of claim 1, wherein the adjusting the PH of the alkaline etchant with ammonia to between 8.8 and 9.2 comprises:
gradually adding ammonia water with preset concentration into the alkaline etching liquid medicine according to a preset adding proportion until the PH value of the alkaline etching liquid medicine is between 8.8 and 9.2;
wherein the preset adding proportion is 0.8-1.2%; the preset concentration is 5% -20%.
7. The fine line alkaline etching method as claimed in claim 1,
in the exposure treatment, the exposure energy is controlled to be 6-8 grids based on an exposure ruler;
in the positive developing treatment, the developing point is controlled to be 40-60%.
8. The method of any one of claims 1-7, wherein the target circuit board has a line width of less than or equal to 3 mils and a pitch of less than or equal to 3 mils.
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| CN105282986A (en) * | 2015-10-14 | 2016-01-27 | 苏州福莱盈电子有限公司 | Production technique of fine flexible circuit boards |
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| US4319955A (en) * | 1980-11-05 | 1982-03-16 | Philip A. Hunt Chemical Corp. | Ammoniacal alkaline cupric etchant solution for and method of reducing etchant undercut |
| US4576677A (en) * | 1983-04-13 | 1986-03-18 | Kernforschungsanlage Julich Gmbh | Method and apparatus for regenerating an ammoniacal etching solution |
| CN101963759A (en) * | 2002-01-30 | 2011-02-02 | 株式会社东芝 | Film forming method, film forming apparatus, pattern forming method, and manufacturing method of semiconductor apparatus |
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