CN116033663A - Fine flexible circuit board and circuit etching compensation method thereof - Google Patents
Fine flexible circuit board and circuit etching compensation method thereof Download PDFInfo
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- CN116033663A CN116033663A CN202310334693.7A CN202310334693A CN116033663A CN 116033663 A CN116033663 A CN 116033663A CN 202310334693 A CN202310334693 A CN 202310334693A CN 116033663 A CN116033663 A CN 116033663A
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Abstract
The invention discloses a fine flexible circuit board and a circuit etching compensation method thereof, wherein the method comprises the following steps: obtaining a circuit substrate to be compensated; the circuit substrate to be compensated is provided with a large-line-distance circuit area, and the line distance between every two adjacent circuits in the large-line-distance circuit area is larger than a first preset threshold value; forming a circuit dry film on a circuit substrate to be compensated according to a preset circuit design by adopting an exposure and development process, and forming a dry film compensation strip in a large-line-spacing circuit area of the circuit substrate to be compensated to obtain a circuit substrate to be etched; and sequentially adopting the processes of etching and removing the film, and treating the circuit substrate to be etched to finish circuit etching so as to form the fine flexible circuit board. The invention can convert the circuit etching of a large-line-space circuit area into the circuit etching of a small-line-space circuit based on the circuit etching compensation of the dry film compensation strip, not only can form a fine circuit, but also can effectively avoid the problem that the circuit etched by the large-line-space circuit has an inverted trapezoid shape, thereby causing the circuit function defect and the high product defect rate.
Description
Technical Field
The invention relates to the field of flexible circuit board manufacturing, in particular to a fine flexible circuit board and a circuit etching compensation method thereof.
Background
With the rapid development of technology and the strong competition of markets, the performance and product structure of various electronic products have higher requirements. In order to provide electronic products with higher performance and tighter product structure, when flexible circuit boards (FPCs, flexible Printed Circuit Board, abbreviated as flexible boards) are used to manufacture electronic products, FPCs are required to meet fine manufacturing requirements, including circuits with various pitches can be manufactured on FPCs.
It is known that etching processes are commonly used to fabricate circuits on FPCs. In order to manufacture a fine flexible circuit board, when a small-pitch circuit (generally, a circuit with a pitch of less than or equal to 60 μm) and a large-pitch circuit (a circuit with a pitch of more than 60 μm) are required to be manufactured on an FPC at the same time, the large-pitch circuit has a high etching liquid exchange speed during etching, and is liable to generate an inverted trapezoid circuit as shown in FIG. 1 (i.e., after etching, the space between copper inside adjacent circuits is larger than that between copper outside, as shown in FIG. 1 d) 1 ＞d 2 ) The method comprises the steps of carrying out a first treatment on the surface of the In fig. 1, 1 is an insulating layer, 2 is a conductive layer, and 5 is a dry film of a circuit.
When the circuit is in an inverted trapezoid shape, the circuit is easy to delaminate from an adjacent insulating layer (such as a polyimide layer, PI layer for short), so that the circuit board is broken, and the circuit function is poor, and the product reject ratio is high.
However, at present, there is no method for compensating the circuit during etching of the large pitch circuit of the fine flexible circuit board so as to avoid the occurrence of the inverted trapezoid circuit.
Disclosure of Invention
In view of the above, the embodiment of the invention provides a fine flexible circuit board and a circuit etching compensation method thereof, so as to solve the problems of poor circuit functions and high product reject ratio caused by inverted trapezium of etched circuits easily caused by etching large-line-spacing circuits of the fine flexible circuit board in the prior art.
The embodiment of the invention provides a circuit etching compensation method of a fine flexible circuit board, which comprises the following steps:
obtaining a circuit substrate to be compensated; the circuit substrate to be compensated is provided with a large-line-distance circuit area, and the line distance between every two adjacent circuits in the large-line-distance circuit area is larger than a first preset threshold value;
forming a circuit dry film on the circuit substrate to be compensated according to a preset circuit design by adopting an exposure and development process, and forming a dry film compensation strip in the large-line-spacing circuit area of the circuit substrate to be compensated to obtain a circuit substrate to be etched;
and sequentially adopting the processes of etching and removing the film to treat the circuit substrate to be etched to finish circuit etching, thereby forming the fine flexible circuit board.
Optionally, the process of exposing and developing forms a dry film on the circuit substrate to be compensated according to a preset circuit design, and forms a dry film compensation strip on the large line-distance circuit area of the circuit substrate to be compensated, so as to obtain the circuit substrate to be etched, including:
determining a first positioning corresponding to the circuit dry film on the circuit substrate to be compensated according to the preset circuit design;
acquiring the line distance between each line and the adjacent line in the large line distance line area according to the preset line design;
according to the line distance, determining the compensation quantity and the compensation width corresponding to the dry film compensation strip between each line and the adjacent line in the large line distance line area;
determining second positioning of all the dry film compensation strips of the large line-distance line area according to the compensation quantity and the compensation width;
manufacturing a mask film for exposure and development based on the first positioning and all the second positioning;
based on the mask film, exposing and developing the circuit substrate to be compensated, forming a circuit dry film on the circuit substrate to be compensated, and forming the dry film compensation strips with corresponding compensation quantity and corresponding compensation width between each circuit and adjacent circuits in the large-line-spacing circuit area, so that the distance between each circuit and the adjacent dry film compensation strips in the large-line-spacing circuit area is smaller than or equal to a second preset threshold value, and obtaining the circuit substrate to be etched;
wherein the second preset threshold is less than the first preset threshold.
Optionally, the first preset threshold is 60 μm, and/or the second preset threshold is in a range of 25-40 μm.
Optionally, the determining, according to the line distance, a compensation number and a compensation width corresponding to the dry film compensation strip between each line and an adjacent line in the large line distance line area includes:
selecting any line in the large line distance line area based on the preset line design;
when the line distance between the selected line and the adjacent line is larger than the first preset threshold value and smaller than or equal to a third preset threshold value, determining that the compensation quantity corresponding to the dry film compensation strip between the selected line and the adjacent line is 1, and the corresponding compensation width is a first preset width;
when the line distance between the selected line and the adjacent line is larger than the third preset threshold value and smaller than or equal to the fourth preset threshold value, determining that the compensation quantity corresponding to the dry film compensation strip between the selected line and the adjacent line is 1, and the corresponding compensation width is a second preset width; wherein the second preset width is greater than the first preset width;
when the line distance between the selected line and the adjacent line is larger than the fourth preset threshold value and smaller than or equal to a fifth preset threshold value, determining that the compensation quantity corresponding to the dry film compensation strip of the selected line and the adjacent line is 2, and the corresponding compensation width is the first preset width;
when the line distance between the selected line and the adjacent line is larger than the fifth preset threshold, determining that the compensation quantity corresponding to the dry film compensation strip between the selected line and the adjacent line is 2, and the corresponding compensation width is the first preset width or the second preset width;
and traversing each line in the large-line-distance line area, and determining the compensation quantity and the compensation width corresponding to the dry film compensation strips between each line and the adjacent lines in the large-line-distance line area according to the same method.
Optionally, the third preset threshold is 80 μm, and/or the fourth preset threshold is 90 μm, and/or the fifth preset threshold is 110 μm.
Optionally, the first preset width ranges from 10 μm to 15 μm, and/or the second preset width ranges from 10 μm to 15 μm.
Optionally, the first preset width is 10 μm, and/or the second preset width is 15 μm.
Optionally, the processing the circuit substrate to be etched by sequentially adopting an etching process and a film removing process to complete circuit etching, thereby forming a fine flexible circuit board, including:
etching the circuit substrate to be etched based on the circuit dry film and the dry film compensation strip on the circuit substrate to be etched, so that all areas of the circuit substrate to be etched except the circuit dry film are etched, forming the circuit is completed, and a circuit board with a film is formed;
and removing the film of the circuit board with the film by adopting a film removing liquid, so that the dry film of the circuit on the circuit board with the film is removed, and circuit etching is completed to form the fine flexible circuit board.
Optionally, the obtaining the circuit substrate to be compensated includes:
providing a flexible substrate;
and sequentially carrying out drilling treatment and in-hole copper plating treatment on the flexible substrate to form the circuit substrate to be compensated.
In addition, the invention also provides a fine flexible circuit board which is manufactured by adopting the circuit etching compensation method.
The invention has the beneficial effects that: firstly, a circuit substrate to be compensated with a large line distance circuit area is obtained, a circuit dry film required according to a preset circuit design is formed on the circuit substrate to be compensated, so that a place without etching is protected, a required circuit is formed by subsequent etching, a circuit function is ensured, and the line distance between the circuits is formed after the place without the circuit dry film is etched; the dry film compensation strip is formed on the large-line-distance line area of the circuit substrate to be compensated, so that the part of the large-line-distance line area, which needs to be etched, can be partially protected, and the part of the large-line-distance line area, which needs to be etched, does not need to be protected originally, so that the effect of line etching compensation can be formed through partial protection, the original line etching process of the large-line-distance line area is converted into a plurality of small-line-distance line etching processes, and the etching liquid medicine exchange speed can be reduced based on the small-line-distance line etching; finally, through the etching and film removing processes, not only can all dry films and dry film compensation strips of the circuit be removed to form a fine circuit which accords with the preset circuit design, but also the problem that the circuit etched by the circuit with large line distance is inverted trapezoid can be effectively avoided, and further the problems of poor circuit function and high product reject ratio are caused, and the method can meet the increasingly fine manufacturing requirement of the FPC at present.
Drawings
The features and advantages of the present invention will be more clearly understood by reference to the accompanying drawings, which are illustrative and should not be construed as limiting the invention in any way, in which:
FIG. 1 is a schematic diagram showing a cross-sectional view of an inverted trapezoid line formed by a large line-spacing line in etching in the conventional art;
fig. 2 is a flowchart showing a circuit etching compensation method of a fine flexible circuit board according to a first embodiment of the present invention;
FIG. 3 is a cross-sectional view of a flexible substrate according to a first embodiment of the present invention;
FIG. 4 is a schematic diagram showing a schematic cross-sectional view of a circuit board to be compensated according to a first embodiment of the present invention;
fig. 5 is a schematic diagram showing a top plan view of a dry film circuit designed on a circuit board to be compensated in accordance with a first embodiment of the present invention;
FIG. 6a shows a cross-sectional model view of a first implementation of the dry film compensator strip design in a large line-space circuit area in accordance with example one of the present invention;
FIG. 6b shows a cross-sectional model view of a second implementation of the dry film compensator strip design in a large line-space circuit area in accordance with example one of the present invention;
FIG. 6c is a cross-sectional view of a third embodiment of the invention showing the design of a dry film compensator strip in a large line-to-line area;
FIG. 6d shows a cross-sectional model view of a fourth implementation of the dry film compensator strip design in the large line-space circuit area in accordance with example one of the present invention;
FIG. 6e shows a cross-sectional model view of a fifth implementation of the dry film compensator strip design in the large line-space circuit area in example one of the present invention;
fig. 7 is a top view of a circuit board to be etched after exposure and development of the circuit board to be compensated in the first embodiment of the present invention;
fig. 8 is a cross-sectional view showing a structure of a circuit board with a film formed in the first embodiment of the present invention;
fig. 9 is a cross-sectional view showing a structure of a fine flexible wiring board formed in the first embodiment of the present invention.
The reference numerals are described as follows:
100. large line space line area 200, small line space line area 1, insulating layer 2, conducting layer 3, through hole 4, hole copper 5, line dry film 6, dry film compensation strip.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to fall within the scope of the invention.
Example 1
The present embodiment provides a circuit etching compensation method for a fine flexible circuit board, as shown in fig. 2, including:
s1, obtaining a circuit substrate to be compensated; the circuit substrate to be compensated is provided with a large-line-distance circuit area, and the line distance between every two adjacent circuits in the large-line-distance circuit area is larger than a first preset threshold value.
Preferably, S1 comprises:
s11: providing a flexible substrate;
s12: and sequentially carrying out drilling treatment and in-hole copper plating treatment on the flexible substrate to form the circuit substrate to be compensated.
The circuit substrate to be compensated with the circuit in the board can be formed through the steps, so that good electric conduction can be formed in the board after the circuit substrate to be compensated is subjected to the subsequent circuit etching compensation step, and the normal circuit function is realized.
Specifically, the flexible substrate may be a double-sided board (the stack of which is composed of an insulating layer and two conductive layers, which are respectively located at two sides of the insulating layer) or a single-sided board (the stack of which is composed of an insulating layer and one conductive layer, and the conductive layer is located at one side of the insulating layer), as shown in fig. 3, the flexible substrate is a double-sided board, and includes an insulating layer 1 and two conductive layers 2, wherein the insulating layer 1 is PI (i.e., made of polyimide), and the two conductive layers 2 are copper foils (either electrolytic copper or rolled copper), and when the copper foils are electrolytic copper, the circuit etching compensation method of the embodiment can also solve the problem that the electrolytic copper material is more easily attacked by etching liquid medicine than the rolled copper material, and further the circuit is more easily caused to be inverted trapezoid in the production process.
Specifically, the flexible substrate shown in fig. 3 is subjected to drilling treatment and in-hole copper plating treatment, and the cross-sectional structure of the circuit substrate to be compensated is shown in fig. 4, 3 is a through hole formed by the drilling treatment, 4 is hole copper formed in the through hole, 100 is a large-line-space circuit area, and 200 is a small-line-space circuit area.
In actual production, after the flexible substrate is drilled, processes such as removing the glue residue, plating the carbon film, AOI (i.e. optical inspection) detecting holes, attaching copper plating dry film and the like can be sequentially adopted to respectively process the flexible substrate, wherein the processes are conventional processes in the FPC manufacturing field, and specific details are not repeated here.
As shown in fig. 2, the method includes:
s2, adopting an exposure and development process, forming a circuit dry film on the circuit substrate to be compensated according to a preset circuit design, and forming a dry film compensation strip in a large-line-spacing circuit area of the circuit substrate to be compensated to obtain the circuit substrate to be etched.
The preset circuit design is a preset circuit design and comprises a circuit specific layout (namely, the specific position of each circuit on the circuit substrate to be compensated), a line width, a line distance and the like; the circuit dry film is formed according to a preset circuit design, so that the area, which is required to be exposed and etched, on the circuit substrate to be compensated can be accurately exposed, and the area, which is not required to be exposed and form a circuit, can be accurately protected; meanwhile, according to the preset line design, a large-line-space line area can be accurately positioned, and a dry film compensation strip for compensating subsequent line etching is conveniently formed, so that the line etching of the large-line-space line area is compensated, the line etching of the large-line-space line area is converted into the line etching of the small-line-space line area, and the problem that the large-line-space line area is etched into an inverted trapezoid structure due to the fact that the line spacing is too wide is avoided, and then line function defects are caused.
The dry film compensation strip of the embodiment is made of the same material as the dry film of the circuit (both dry films are formed in the process of exposure and development), is a polymer compound, and can generate a polymerization reaction (the reaction process of synthesizing a polymer from a monomer) to form a stable substance to be attached to the board surface after irradiation of ultraviolet rays, so that the functions of electroplating and etching are achieved. The dry film of the circuit formed in this embodiment protects the area of the circuit substrate to be compensated, which is not required to be exposed and form the circuit, and accurately exposes the area to be exposed and etched, after subsequent etching, the protected areas form the final circuit, and the copper foil of the exposed areas is etched to form the line spacing between the circuits.
Preferably, S2 comprises:
s21: determining a first positioning corresponding to the circuit dry film on the circuit substrate to be compensated according to the preset circuit design;
s22: acquiring the line distance between each line and the adjacent line in the large line distance line area according to the preset line design;
s23: according to the line distance, determining the compensation quantity and the compensation width corresponding to the dry film compensation strip between each line and the adjacent line in the large line distance line area;
s24: determining second positioning of all the dry film compensation strips of the large line-distance line area according to the compensation quantity and the compensation width;
s25: manufacturing a mask film for exposure and development based on the first positioning and all the second positioning;
s26: based on the mask film, exposing and developing the circuit substrate to be compensated, forming a circuit dry film on the circuit substrate to be compensated, and forming the dry film compensation strips with corresponding compensation quantity and corresponding compensation width between each circuit and adjacent circuits in the large-line-spacing circuit area, so that the distance between each circuit and adjacent dry film compensation strips in the large-line-spacing circuit area is smaller than or equal to a second preset threshold value, and obtaining the circuit substrate to be etched;
wherein the second preset threshold is less than the first preset threshold.
According to a preset circuit design, the position of the circuit dry film and the width of the circuit dry film which are required to be exposed and developed by the circuit substrate to be compensated can be known, namely, the first positioning of the circuit dry film is determined; meanwhile, the line distance between each line and the adjacent line in the large line distance line area can be known, and the corresponding quantity (namely the compensation quantity) and the corresponding width (namely the compensation width) of the dry film compensation strips to be exposed and developed are correspondingly determined according to the line distances; from these determined compensation amounts and compensation widths, a second location of all dry film compensation strips (including the specific location and specific width of each dry film compensation strip) of the desired design is further determined; based on the first positioning of the circuit dry film and the second positioning of all dry film compensation strips, a mask film which can form the circuit dry film and all dry film compensation strips is conveniently manufactured; finally, based on the mask film, exposure and development are carried out, so that a circuit dry film meeting the design requirement can be formed, and a dry film compensation strip for circuit etching compensation can be formed; the method has the advantages that the area needing etching between every two adjacent lines in the large-line-distance line area is divided into a plurality of small-line-distance areas, the phenomenon that lines caused by fast liquid medicine exchange during etching of the large-line-distance lines are inverted trapezoid can be avoided based on the etching of the small-line-distance areas, the liquid medicine exchange speed during etching between each line and the adjacent lines in the large-line-distance line area is slowed down through compensation of the dry film compensation strip, the line etching compensation effect is formed, and the product quality is improved.
In this embodiment, the top plane structure of the circuit dry film designed on the circuit substrate to be compensated is shown in fig. 5 (the through holes and the hole copper in fig. 5 are not shown), 5 in fig. 5 is the circuit dry film, and the inner layer of the circuit dry film is the circuit (not shown in the figure) left after the subsequent etching; thus, the line distance between every two adjacent lines (i.e., the distance between the line dry films 5 formed outside of every two adjacent lines) of the large line-space line area 100 is greater than the first preset threshold value, and the line distance between every two adjacent lines (i.e., the distance between the line dry films 5 formed outside of every two adjacent lines) of the small line-space line area 200 is less than or equal to the first preset threshold value. The first preset threshold may be preset according to practical situations, and is set to 60 μm in this embodiment.
The second preset threshold value is smaller than the first preset threshold value and is also a preset threshold value, and the range of the second preset threshold value in the embodiment is 25-40 μm. In S23-S24, the specific position and specific width (namely the second positioning) of the dry film compensation strips are determined so as to ensure that the distance between each line and the adjacent dry film compensation strips is within the range of 25-40 mu m.
When the dry film and the dry film compensating strip are formed based on the mask film, the dry film and the compensating strip are attached to the outer surface of the outermost layer of the circuit substrate to be compensated (the outermost layer of the circuit substrate to be compensated is usually a conductive layer, such as copper foil).
Preferably, S23 includes:
s231: selecting any line in the large line distance line area based on the preset line design;
s232a: when the line distance between the selected line and the adjacent line is larger than the first preset threshold value and smaller than or equal to a third preset threshold value, determining that the compensation quantity corresponding to the dry film compensation strip between the selected line and the adjacent line is 1, and the corresponding compensation width is a first preset width;
s232b: when the line distance between the selected line and the adjacent line is larger than the third preset threshold value and smaller than or equal to the fourth preset threshold value, determining that the compensation quantity corresponding to the dry film compensation strip between the selected line and the adjacent line is 1, and the corresponding compensation width is a second preset width; wherein the second preset width is greater than the first preset width;
s232c: when the line distance between the selected line and the adjacent line is larger than the fourth preset threshold value and smaller than or equal to a fifth preset threshold value, determining that the compensation quantity corresponding to the dry film compensation strip between the selected line and the adjacent line is 2, and the corresponding compensation width is the first preset width;
s232d: when the line distance between the selected line and the adjacent line is larger than the fifth preset threshold, determining that the compensation quantity corresponding to the dry film compensation strip between the selected line and the adjacent line is 2, and the corresponding compensation width is the first preset width or the second preset width;
s233: and traversing each line in the large-line-distance line area, and determining the compensation quantity and the compensation width corresponding to the dry film compensation strips between each line and the adjacent lines in the large-line-distance line area according to the same method.
For any line in the large line space, when the distance between the line and the adjacent line is larger than a first preset threshold (i.e. meets the large line space requirement) and smaller than or equal to a third preset threshold, a dry film compensation strip with a width being the first preset width can be designed between the line and the adjacent line (i.e. the compensation number of the dry film compensation strips between the selected line and the adjacent line at the moment is 1, and the compensation width is the first preset width). As shown in FIG. 6a, a line L is selected in the figure 1 Adjacent to the line L 2 The distance between them is set aslWhen (when)l 1 ＜l≤l 3 At the time of L 1 And L is equal to 2 A width D is designed at the 1/2 position 1 After forming the dry film compensating strip 6 according to the design, the circuit L is made 1 (specifically, L 1 The distance between the upper formed line dry film 5) and the adjacent dry film compensation strip 6l´Less than or equal to a second preset threshold (set tol2) And further can make the line L 2 Distance from adjacent dry film compensation strip 6l"Is also less than or equal to a second preset thresholdl 2 。
For any line of the large line-space line area, when the distance between the line and the adjacent line is larger than a third preset threshold valuel 3 And is less than or equal to a fourth preset threshold (set tol 4 ) In this case, a dry film compensation strip with a width of a second preset width may be designed between the dry film compensation strip and the adjacent line (i.e. the compensation number of the dry film compensation strip between the selected line and the adjacent line is 1, and the compensation width is the second preset width). As shown in FIG. 6b, a line L is selected in the figure 1 Adjacent to the line L 2 The distance between them is set aslWhen (when)l 3 ＜l≤l 4 At the time of L 1 And L is equal to 2 A width D is designed at the 1/2 position 2 Dry film compensating strip 6 of (i) even line L 1 Adjacent to the line L 2 The spacing between them is greater than in FIG. 6a, but due to D 2 ＞D 1 After the dry film compensation strip 6 is formed according to the design, the line L can still be made 1 Distance from adjacent dry film compensation strip 6l´Less than or equal to a second preset thresholdl 2 The method comprises the steps of carrying out a first treatment on the surface of the And further can make the line L 2 Distance from adjacent dry film compensation strip 6l"Is also less than or equal to a second preset thresholdl 2 。
It should be noted that the specific positions of the dry film compensation strips shown in fig. 6a and 6b may be omitted from the L 1 And L is equal to 2 The 1/2 position between the two can be finely adjusted according to the actual situation, so long as L can be ensured 1 And L 2 The distance between each dry film compensation strip and the adjacent dry film compensation strip is smaller than or equal to a second preset threshold valuel 2 And (3) obtaining the product.
For any line of the large line-space line area, when the distance between the line and the adjacent line is larger than a fourth preset threshold valuel 4 And is less than or equal to a fifth preset threshold (set tol 5 ) When the original piece D 1 Dry film compensation strip or strip D 2 The distance between the selected circuit and the adjacent dry film compensation strip cannot be smaller than or equal to a second preset threshold valuel 2 At this time, two dry film compensating strips with the width of the first preset width can be designed between the two adjacent lines (namely, the compensating number of the dry film compensating strips between the selected line and the adjacent line at this time is 2, and the compensating width is the first preset width). As shown in FIG. 6c, a line L is selected in the figure 1 Adjacent to the line L 2 The distance between them is set aslWhen (when)l 4 ＜l≤l 5 At the time of according to the design at L 1 And L is equal to 2 A width D is respectively formed at the 1/3 position and the 2/3 position 1 The dry film compensation strip 6 of (1) can enable the circuit L to be 1 Distance between the nearest adjacent dry film compensating strips 6l´Less than or equal to a second preset thresholdl 2 The method comprises the steps of carrying out a first treatment on the surface of the And further can make the line L 2 Distance between the nearest adjacent dry film compensating strips 6l"Is also less than or equal to a second preset thresholdl 2 。
For any line of the large line-space line area, when the distance between the line and the adjacent line is larger than a fifth preset threshold valuel 5 (but not much larger thanl 5 ) At this time, FIG. 6c shows two original strips D 1 The distance between the selected circuit and the adjacent dry film compensation strip cannot be smaller than or equal to a second preset threshold valuel 2 Two dry film compensating strips with the second preset width can be designed between the adjacent circuit and the adjacent circuit (namely the compensating number of the dry film compensating strips between the selected circuit and the adjacent circuit is 2, and the compensating width is the firstTwo preset widths). As shown in FIG. 6d, a line L is selected in the figure 1 Adjacent to the line L 2 The distance between them is set aslWhen (when)l＞l 5 At the time of L 1 And L is equal to 2 A width D is respectively formed at the 1/3 position and the 2/3 position 2 The compensation width of the dry film compensation strip 6 (i.e. the compensation quantity and the compensation position of the dry film compensation strip are unchanged, and the compensation width is increased by D 1 To D 2 ) For the same reason D 2 ＞D 1 Can make the line L 1 Distance between the nearest adjacent dry film compensating strips 6l´Less than or equal to a second preset thresholdl 2 The method comprises the steps of carrying out a first treatment on the surface of the And further can make the line L 2 Distance between the nearest adjacent dry film compensating strips 6l"Is also less than or equal to a second preset thresholdl 2 。
It should be noted that the specific positions of the dry film compensation strips shown in fig. 6c and 6d may not be set at L 1 And L is equal to 2 The position 1/3 and the position 2/3 can be finely adjusted according to the actual situation, so long as L can be ensured 1 And L 2 The distance between each dry film compensation strip and the adjacent dry film compensation strip is smaller than or equal to a second preset threshold valuel 2 And (3) obtaining the product.
When the distance between the selected line and the adjacent line is greater than the fifth preset threshold valuel 5 (and is much larger thanl 5 ) When two strips D are designed at the positions of the original FIG. 6c and FIG. 6D 1 Or D 2 The dry film compensation strips of the device can not lead the selected circuit and the adjacent dry film compensation strip to be smaller than or equal to a second preset threshold valuel 2 The number of the dry film compensating strips can be maintained at this time, and the purpose that the selected line and the adjacent dry film compensating strips are smaller than or equal to a second preset threshold value is achieved by adjusting the specific positions of the dry film compensating strips (the compensating number of the dry film compensating strips between the selected line and the adjacent line at this time is 2, and the compensating width is the first preset width or the second preset width). As shown in FIG. 6e, a line L is selected in the figure 1 Adjacent to the line L 2 The distance between them is set aslWhen (when)lFar greater thanl 5 At the time of L 1 And L is equal to 2 Is close to L 1 At (2), and at L 1 And L is equal to 2 Is close to L 2 Respectively design a width D at the position of 1 Or D 2 After forming two dry film compensating strips 6 according to the design, the circuit L can be made 1 The distance between the nearest adjacent dry film compensation strips 6 is smaller than or equal to a second preset threshold valuel 2 At the same time can enable the line L 2 The distance between the nearest adjacent dry film compensation strip 6 is smaller than or equal to a second preset threshold valuel 2 . Wherein the width of the dry film compensation strip is specifically D 1 And D 2 Can be selected according to the specific position of the dry film compensation strip, so long as the line L is ensured 1 And line L 2 The distance between the adjacent dry film compensation strips (includingl´Andl") Are all smaller than or equal tol 2 And (3) obtaining the product.
Specifically, the third preset threshold is 80 μm, and/or the fourth preset threshold is 90 μm, and/or the fifth preset threshold is 110 μm. In the present embodiment, a third preset threshold valuel 3 Taking 80 μm, fourth preset thresholdl 4 Taking 90 μm, fifth preset thresholdl 5 110 μm was taken.
Specifically, the first preset width ranges from 10 μm to 15 μm, and/or the second preset width ranges from 10 μm to 15 μm.
The range of the first preset width and the second preset width in the range can not only realize the conversion of the etching process of the large-line-distance line into the etching process of a plurality of small line distances, but also avoid the formation of an inverted trapezoid structure due to the excessively wide line distance; the narrower dry film compensation strips can be etched away along with the etching of the conductive layer in the subsequent etching process due to the preset widths of the two narrower ranges, so that the circuit with design requirements is obtained.
Specifically, the first preset width is 10 μm.
Specifically, the first preset width is 15 μm.
The specific designs of the compensation number and compensation width of the dry film compensation strip between each line and the adjacent line in the large line-space line area of this embodiment are shown in table 1.
TABLE 1 Compensation quantity and Compensation Width of Dry film Compensation strips
Because the large line distance line area can contain a plurality of lines, dry film compensation strips corresponding to the compensation quantity and the compensation width are designed for each line according to the mode, and finally, the liquid medicine exchange speed during the line etching in the large line distance line area can be reduced during the subsequent line etching based on the formed line dry films and all dry film compensation strips, so that the line is prevented from presenting an inverted trapezoid structure, the line etching quality is improved, and the product quality is further improved.
For the large line space line area shown in fig. 5, the dry film compensation strip is designed according to the design method described above, and the top plane structure of the dry film compensation strip formed in the large line space line area after exposure and development is shown in fig. 7.
As shown in fig. 2, the method includes:
and S3, sequentially adopting the processes of etching and removing films, and treating the circuit substrate to be etched to finish circuit etching so as to form the fine flexible circuit board.
Preferably, S3 comprises:
s31: etching the circuit substrate to be etched based on the circuit dry film and the dry film compensation strip on the circuit substrate to be etched, so that all areas of the circuit substrate to be etched except the circuit dry film are etched, forming the circuit is completed, and a circuit board with a film is formed;
s33: and removing the film of the circuit board with the film by adopting a film removing liquid, so that the dry film of the circuit on the circuit board with the film is removed, and circuit etching is completed to form the fine flexible circuit board.
After the circuit dry film and the dry film compensating strip are formed according to the steps described in the step S2, etching treatment is performed based on the circuit dry film and the dry film compensating strip uniformly, on one hand, not only the whole area of the circuit board to be etched except the circuit dry film and the dry film compensating strip can be etched, but also the area of the dry film compensating strip can be etched (namely, all the areas of the circuit substrate to be etched except the circuit dry film are etched) due to the fact that the width of the dry film compensating strip is usually narrower, so that a circuit meeting the design requirement is formed; on the other hand, the etching process of the large-line-distance circuit area can be converted into the circuit etching of the small-line-distance based on the compensation function of the dry film compensation strip, the exchange speed of etching liquid medicine is slowed down, the reverse trapezoid structure formed by etching is avoided, the etching quality is improved, and then the circuit forming of the high-quality circuit outside the board is realized, so that the circuit board with the film is formed; finally, removing the dry film by adopting a film removing liquid, so that the dry film of the circuit can be removed, and the dry film compensation strip which is not completely removed in the etching process can be further removed, thereby maximally optimizing the quality of the fine flexible circuit board; on the premise of realizing circuit etching compensation, a fine flexible circuit board meeting the fine circuit manufacturing requirement is formed.
In the actual production process, although the dry film compensation strip protects part of the copper foil in the large-line-distance circuit area, the dry film compensation strip is usually narrower in width, and can form side etching on the copper foil protected by the dry film compensation strip through the etching action of etching liquid medicine, so that the part of the copper foil is etched away along with the etching process, a part of the dry film compensation strip can fall off along with the etching of the copper foil, or a part of the dry film compensation strip can be attached to the circuit substrate without falling along with the etching of the copper foil, and the part of the dry film compensation strip can be removed along with the action of the film removing liquid in the subsequent film removing process, so that the finally formed board external circuit can be ensured to meet the preset circuit design, and the action of circuit etching compensation can be achieved.
In this embodiment, the cross-sectional structure of the formed film-attached wiring board is shown in fig. 8 through the step of S31, and the cross-sectional structure of the formed fine flexible wiring board is shown in fig. 9 through the step of S32.
In the actual production process, before step S31, the embodiment may further perform chemical cleaning on the circuit substrate to be compensated, and after step S32, the fine flexible circuit board is processed by using processes such as AOI inspection, chemical cleaning, and cutting, so as to form a circuit board actually required by the final product. Similarly, the above processes are also conventional in the field of FPC fabrication, and specific details are not described here again.
According to the circuit etching compensation method of the fine flexible circuit board, firstly, a circuit substrate to be compensated provided with a circuit area with a large line distance is obtained, and a circuit dry film required according to a preset circuit design is formed on the circuit substrate to be compensated, so that a place without etching is protected, a required circuit is formed by utilizing subsequent etching, a circuit function is ensured, and the line distance between the circuits is formed after etching at the place without the circuit dry film; the dry film compensation strip is formed on the large-line-distance line area of the circuit substrate to be compensated, so that the part of the large-line-distance line area to be etched can be partially protected, and the part of the large-line-distance line area to be etched is not required to be protected, so that the effect of line etching compensation can be formed through partial protection, the original line etching process of the large-line-distance line area is converted into the small-line-distance line etching process, and the etching liquid medicine exchange speed can be reduced based on the small-line-distance line etching; finally, through the etching and film removing processes, not only can all dry films and dry film compensation strips of the circuit be removed to form a fine circuit which accords with the preset circuit design, but also the problem that the circuit etched by the circuit with large line distance is inverted trapezoid can be effectively avoided, and further the problems of poor circuit function and high product reject ratio are caused, and the method can meet the increasingly fine manufacturing requirement of the FPC at present.
Example 2
The embodiment provides a fine flexible circuit board manufactured by the circuit etching compensation method in the first embodiment.
The structure of the fine flexible circuit board formed by the embodiment is shown in fig. 9, which is manufactured by adopting the circuit etching compensation method, and the circuit etching compensation based on the dry film compensation strip can convert the circuit etching of the large-line-distance circuit area into the small-line-distance circuit etching, so that fine circuits conforming to the preset circuit design can be formed, the problem that the circuits etched by the large-line-distance circuits are inverted trapezoids can be effectively avoided, further, the problems of poor circuit functions and high product reject ratio are caused, and the method can adapt to the increasingly fine manufacturing requirements of the FPC at the present stage.
The circuit etching compensation method adopted by the fine flexible circuit board in this embodiment is the same as the steps of the method described in the first embodiment, so the details of this embodiment are not described in detail in the first embodiment, and the detailed description of this embodiment is omitted.
Although embodiments of the present invention have been described in connection with the accompanying drawings, various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the invention, and such modifications and variations are within the scope of the invention as defined by the appended claims.
Claims (10)
1. A circuit etch compensation method for a fine flexible circuit board, comprising:
obtaining a circuit substrate to be compensated; the circuit substrate to be compensated is provided with a large-line-distance circuit area, and the line distance between every two adjacent circuits in the large-line-distance circuit area is larger than a first preset threshold value;
forming a circuit dry film on the circuit substrate to be compensated according to a preset circuit design by adopting an exposure and development process, and forming a dry film compensation strip in the large-line-spacing circuit area of the circuit substrate to be compensated to obtain a circuit substrate to be etched;
and sequentially adopting the processes of etching and removing the film to treat the circuit substrate to be etched to finish circuit etching, thereby forming the fine flexible circuit board.
2. The circuit etching compensation method of claim 1, wherein the process of exposing and developing is performed to form a dry film of circuit on the circuit substrate to be compensated according to a predetermined circuit design, and form a dry film compensation bar on the large line-spacing circuit area of the circuit substrate to be compensated, so as to obtain the circuit substrate to be etched, and the method comprises the steps of:
determining a first positioning corresponding to the circuit dry film on the circuit substrate to be compensated according to the preset circuit design;
acquiring the line distance between each line and the adjacent line in the large line distance line area according to the preset line design;
according to the line distance, determining the compensation quantity and the compensation width corresponding to the dry film compensation strip between each line and the adjacent line in the large line distance line area;
determining second positioning of all the dry film compensation strips of the large line-distance line area according to the compensation quantity and the compensation width;
manufacturing a mask film for exposure and development based on the first positioning and all the second positioning;
based on the mask film, exposing and developing the circuit substrate to be compensated, forming a circuit dry film on the circuit substrate to be compensated, and forming the dry film compensation strips with corresponding compensation quantity and corresponding compensation width between each circuit and adjacent circuits in the large-line-spacing circuit area, so that the distance between each circuit and the adjacent dry film compensation strips in the large-line-spacing circuit area is smaller than or equal to a second preset threshold value, and obtaining the circuit substrate to be etched;
wherein the second preset threshold is less than the first preset threshold.
3. The line etching compensation method of a fine flexible circuit board according to claim 2, wherein the first preset threshold value is 60 μm and/or the second preset threshold value is in a range of 25 to 40 μm.
4. The circuit etching compensation method of claim 2, wherein determining the compensation quantity and compensation width corresponding to the dry film compensation strip between each circuit and the adjacent circuit in the large-pitch circuit area according to the line pitch comprises:
selecting any line in the large line distance line area based on the preset line design;
when the line distance between the selected line and the adjacent line is larger than the first preset threshold value and smaller than or equal to a third preset threshold value, determining that the compensation quantity corresponding to the dry film compensation strip between the selected line and the adjacent line is 1, and the corresponding compensation width is a first preset width;
when the line distance between the selected line and the adjacent line is larger than the third preset threshold value and smaller than or equal to the fourth preset threshold value, determining that the compensation quantity corresponding to the dry film compensation strip between the selected line and the adjacent line is 1, and the corresponding compensation width is a second preset width; wherein the second preset width is greater than the first preset width;
when the line distance between the selected line and the adjacent line is larger than the fourth preset threshold value and smaller than or equal to a fifth preset threshold value, determining that the compensation quantity corresponding to the dry film compensation strip between the selected line and the adjacent line is 2, and the corresponding compensation width is the first preset width;
when the line distance between the selected line and the adjacent line is larger than the fifth preset threshold, determining that the compensation quantity corresponding to the dry film compensation strip between the selected line and the adjacent line is 2, and the corresponding compensation width is the first preset width or the second preset width;
and traversing each line in the large-line-distance line area, and determining the compensation quantity and the compensation width corresponding to the dry film compensation strips between each line and the adjacent lines in the large-line-distance line area according to the same method.
5. The line etching compensation method of a fine flexible wiring board according to claim 4, wherein the third preset threshold value is 80 μm, and/or the fourth preset threshold value is 90 μm, and/or the fifth preset threshold value is 110 μm.
6. The circuit etching compensation method of a fine flexible circuit board according to claim 4, wherein the first preset width is in a range of 10-15 μm and/or the second preset width is in a range of 10-15 μm.
7. The line etching compensation method of a fine flexible wiring board according to claim 4, wherein the first preset width is 10 μm and/or the second preset width is 15 μm.
8. The circuit etching compensation method of any one of claims 1 to 7, wherein the sequentially etching and stripping processes are used to process the circuit substrate to be etched to complete circuit etching, thereby forming a fine flexible circuit board, comprising:
etching the circuit substrate to be etched based on the circuit dry film and the dry film compensation strip on the circuit substrate to be etched, so that all areas of the circuit substrate to be etched except the circuit dry film are etched, forming the circuit is completed, and a circuit board with a film is formed;
and removing the film of the circuit board with the film by adopting a film removing liquid, so that the dry film of the circuit on the circuit board with the film is removed, and circuit etching is completed to form the fine flexible circuit board.
9. The line etching compensation method of a fine flexible wiring board according to any one of claims 1 to 7, wherein the obtaining a wiring substrate to be compensated includes:
providing a flexible substrate;
and sequentially carrying out drilling treatment and in-hole copper plating treatment on the flexible substrate to form the circuit substrate to be compensated.
10. A fine flexible circuit board manufactured by the circuit etching compensation method according to any one of claims 1 to 9.
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| CN202310334693.7A CN116033663B (en) | 2023-03-31 | 2023-03-31 | Fine flexible circuit board and circuit etching compensation method thereof |
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| CN202310334693.7A CN116033663B (en) | 2023-03-31 | 2023-03-31 | Fine flexible circuit board and circuit etching compensation method thereof |
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|---|---|---|---|---|
| TW200539311A (en) * | 2004-05-10 | 2005-12-01 | Taiwan Semiconductor Mfg | Method utilizing compensation features in semiconductor processing |
| TW201430903A (en) * | 2013-01-23 | 2014-08-01 | United Microelectronics Corp | Method for forming semiconductor device |
| CN104010445A (en) * | 2014-05-09 | 2014-08-27 | 东莞市五株电子科技有限公司 | Dynamic compensation manufacturing method for fine circuit |
| CN105430908A (en) * | 2015-10-29 | 2016-03-23 | 深圳市五株科技股份有限公司 | Linewidth compensation method for manufacturing printed circuit board |
| CN108024454A (en) * | 2017-12-14 | 2018-05-11 | 悦虎电路(苏州)有限公司 | A kind of line build-out method based on 1.5mil wiring boards |
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2023
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW200539311A (en) * | 2004-05-10 | 2005-12-01 | Taiwan Semiconductor Mfg | Method utilizing compensation features in semiconductor processing |
| TW201430903A (en) * | 2013-01-23 | 2014-08-01 | United Microelectronics Corp | Method for forming semiconductor device |
| CN104010445A (en) * | 2014-05-09 | 2014-08-27 | 东莞市五株电子科技有限公司 | Dynamic compensation manufacturing method for fine circuit |
| CN105430908A (en) * | 2015-10-29 | 2016-03-23 | 深圳市五株科技股份有限公司 | Linewidth compensation method for manufacturing printed circuit board |
| CN108024454A (en) * | 2017-12-14 | 2018-05-11 | 悦虎电路(苏州)有限公司 | A kind of line build-out method based on 1.5mil wiring boards |
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