TWI762934B - Method for patterning conductive layer and conductive structure - Google Patents

Abstract

One aspect of the present invention provides a method for patterning a conductive layer. The method includes: forming a conductive layer on a surface of a substrate, a contact angle of the conductive layer being greater than or equal to 50 degrees and less than or equal to 90 degrees; forming a patterned photoresist layer on a surface of the conductive layer away from the substrate; and etching the conductive layer with an aqueous etching solution to remove a portion of the conductive layer not covered by the patterned photoresist layer, thereby obtaining a patterned conductive layer. Another aspect of the present invention provides a conductive structure.

Description

Conductive layer patterning method and conductive structure

The invention relates to the field of wet etching, in particular to a method for patterning a conductive layer and a conductive structure.

Conventionally, when the conductive layer is patterned by wet etching, there is a phenomenon that the aqueous etchant will quickly penetrate into the interface between the photoresist layer and the conductive layer, causing the photoresist layer to be easily peeled off and the etching width to increase. In addition, this problem is more serious when making thin lines and wide line spacing (for example, the line width and line spacing are each 100 μm), so that the line width and line spacing of wet etching cannot be reduced.

One aspect of the present invention provides a method for patterning a conductive layer, which includes the following steps: forming a conductive layer on a surface of a substrate, the contact angle of the conductive layer being greater than or equal to 50 degrees and less than or equal to 90 degrees; A patterned photoresist layer is formed on the surface of the substrate; and the conductive layer is etched with an aqueous etchant to remove the portion of the conductive layer not covered by the patterned photoresist layer, thereby obtaining patterning the conductive layer.

Another aspect of the present invention provides a conductive structure comprising a substrate and a patterned conductive layer on the substrate, wherein the contact angle of the patterned conductive layer is greater than or equal to 50 degrees and less than or equal to 90 degrees.

In the method for patterning the conductive layer and the conductive structure, the contact angle of the conductive layer is greater than or equal to 50 degrees and less than or equal to 90 degrees, that is, the surface of the conductive layer has poor hydrophilicity, which reduces the effect of the aqueous etching solution on the patterned photoresist layer and the patterned photoresist layer. The penetration speed of the interface of the hydrophilic conductive film avoids the phenomenon of side etching of the conductive layer, thereby reducing the risk of peeling off of the patterned photoresist layer and the risk of increasing the etching width caused by the side etching, which is beneficial to improve the wet etching efficiency. precision.

10: Substrate

20: Conductive layer

22: Hydrophilic conductive film

24: Weak hydrophilic conductive film

30: Patterned photoresist layer

40: Water-based etching solution

50: Patterned Conductive Layer

100: Conductive structure

42: Touch electrode

422: touch drive electrode

424: touch sensing electrode

X: first direction

Y: the second direction

44: Route

FIG. 1 is a flowchart of a method for patterning a conductive layer according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of step S1 of a method for patterning a conductive layer provided by an embodiment of the present invention.

FIG. 3 is a schematic diagram of step S2 of a method for patterning a conductive layer provided by an embodiment of the present invention.

FIG. 4 is a schematic diagram of etching the conductive layer by using an aqueous etching solution in step S3 of the method for patterning the conductive layer according to an embodiment of the present invention.

5 is a schematic diagram of obtaining a patterned conductive layer in step S3 of the method for patterning a conductive layer according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of etching the conductive layer by using an aqueous etchant in step S3 of the method for patterning a conductive layer provided by another embodiment of the present invention.

FIG. 7 is a plan view of a conductive structure provided by an embodiment of the present invention.

FIG. 1 is a flowchart of a method for patterning a conductive layer according to an embodiment of the present invention. The method includes the following steps.

S1 : forming a conductive layer 20 on the surface of a substrate 10 . The contact angle of the conductive layer 20 is greater than or equal to 50° and less than or equal to 90°. The contact angle refers to the tangent of the gas-liquid interface at the intersection of the gas, liquid and solid phases, and the angle between the tangent on the liquid side and the solid-liquid interface. The contact angle is a measure of the degree of wetting. The smaller the contact angle, the easier it is for the liquid to wet the solid, and the better the hydrophilicity of the surface of the solid. Conversely, the larger the contact angle, the less likely the liquid to wet the solid, and the hydrophobicity of the surface of the solid. the better. In step S1, the contact angle of the conductive layer 20 is greater than or equal to 50°, that is, the hydrophilicity of the surface of the conductive layer 20 is poor.

In one embodiment, the material of the substrate 10 may be glass, polyimide (PI), polyethylene terephthalate (PET), or polycarbonate (PC). .

In one embodiment, as shown in FIG. 2 , step S1 includes forming a hydrophilic conductive film 22 on the surface of the substrate 10 and forming a weak hydrophilic film on the surface of the hydrophilic conductive film 22 away from the substrate 10 . Conductive film 24 . The contact angle of the weakly hydrophilic conductive film 24 is greater than or equal to 50° and less than or equal to 90°.

By forming the weakly hydrophilic conductive film 24 on the hydrophilic conductive film 22, the penetration speed of the aqueous etching solution 40 between the patterned photoresist layer 30 and the hydrophilic conductive film 22 in the subsequent wet etching step can be reduced, which is beneficial to improve Accuracy of wet etching.

In one embodiment, the hydrophilic conductive film 22 and the weakly hydrophilic conductive film 24 are made of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(ethylene benzenesulfonate). Poly(styrene sulfonate), PSS) composite material (abbreviated as PEDOT: PSS). in, PEDOT: PSS has high conductivity and high transparency, and can be used to make transparent electrodes or transparent leads. In addition, PEDOT has hydrophobicity and PSS has hydrophilicity. By adjusting the mass ratio of PEDOT to PSS in the PEDOT:PSS conductive film, the hydrophilicity of the PEDOT:PSS conductive film can be reduced.

In one embodiment, the mass ratio of PSS to PEDOT in the hydrophilic conductive film 22 is defined as R1, and the mass ratio of PSS to PEDOT in the weakly hydrophilic conductive film 24 is defined as R2, where R2 is less than R1. That is, the material of the weakly hydrophilic conductive film 24 is composed of a PEDOT:PSS conductive film with a relatively low PSS mass ratio. than R1. By reducing the mass ratio of the hydrophilic PSS in the weakly hydrophilic conductive film 24, the contact angle of the weakly hydrophilic conductive film 24 is between 50 degrees and 90 degrees, thereby reducing the contact angle of the weakly hydrophilic conductive film 24. The hydrophilicity further reduces the penetration speed of the aqueous etching solution 40 between the patterned photoresist layer 30 and the hydrophilic conductive film 22 .

R1

100，弱親水性導電膜24中PSS與PEDOT質量比R2的範圍為1

R2

9.9。於一實施例中，親水性導電膜22的厚度為0.5μm至2μm，弱親水性導電膜24的厚度為1nm至100nm。藉此，一方面，弱親水性導電膜24的厚度不會過薄，有利於降低後續濕蝕刻步驟中水性蝕刻液40在圖案化的光阻層30與親水性導電膜22之間的滲透速度，利於提高濕蝕刻的精度；另一方面，弱親水性導電膜24的厚度又不會過厚，可保持蝕刻形成的導電線路具有良好的導電性。 In one embodiment, the mass ratio R1 of PSS to PEDOT in the hydrophilic conductive film 22 is in the range of 10

R1

100, the range of the mass ratio R2 of PSS to PEDOT in the weakly hydrophilic conductive film 24 is 1

R2

9.9. In one embodiment, the thickness of the hydrophilic conductive film 22 is 0.5 μm to 2 μm, and the thickness of the weakly hydrophilic conductive film 24 is 1 nm to 100 nm. Therefore, on the one hand, the thickness of the weakly hydrophilic conductive film 24 will not be too thin, which is beneficial to reduce the penetration speed of the aqueous etching solution 40 between the patterned photoresist layer 30 and the hydrophilic conductive film 22 in the subsequent wet etching step , which is beneficial to improve the precision of wet etching; on the other hand, the thickness of the weakly hydrophilic conductive film 24 is not too thick, which can keep the conductive lines formed by etching with good conductivity.

S2 : forming a patterned photoresist layer 30 on the surface of the conductive layer 20 away from the substrate 10 .

As shown in FIG. 3 , the patterned photoresist layer 30 is formed on the surface of the weakly hydrophilic conductive film 24 away from the substrate 10 .

In one embodiment, step S2 may include the following steps: forming a photoresist layer (not shown) on the conductive layer 20 , and exposing and developing the photoresist layer by using a photomask (not shown). , and then the patterned photoresist layer 30 is obtained.

In one embodiment, the conductive layer 20 is used for patterning to form a plurality of touch electrodes 42 (as shown in FIG. 7 ) and traces 44 connecting the touch electrodes 42 (as shown in FIG. 7 ), then the mask is pre-fabricated. Patterns of the plurality of touch electrodes 42 and patterns of the traces 44 are provided.

S3 : etching the conductive layer 20 with the aqueous etchant 40 to remove the portion of the conductive layer 20 not covered by the patterned photoresist layer 30 , thereby obtaining a patterned conductive layer 50 .

As shown in FIG. 4 , in step S3 , the aqueous etching solution 40 penetrates into the conductive layer 20 exposed from the patterned photoresist layer 30 . Wherein, due to the arrangement of the weak hydrophilic conductive film 24 , the penetration speed of the aqueous etchant 40 at the interface between the patterned photoresist layer 30 and the hydrophilic conductive film 22 can be reduced. Thereby, the phenomenon that the aqueous etchant 40 quickly penetrates under the patterned photoresist layer 30 and the side etching of the conductive layer 20 is avoided, thereby preventing the patterned photoresist layer 30 from peeling off and the etching width being enlarged due to the side etching. It is beneficial to achieve the purpose of wet etching with precise thin line width of photoresist.

In one embodiment, step S3 further includes the step of removing the patterned photoresist layer 30 .

In another embodiment, as shown in FIG. 6 , the conductive layer 20 formed in step S1 is a single layer. The single-layer conductive layer 20 is weakly hydrophilic.

R3

9.9，藉由調整R3的範圍，使得導電層20的接觸角在50度至90度之間，進而改善蝕刻過程中，水性蝕刻液40在圖案化的光阻層30與導電層20之間的滲透速度。 In one embodiment, the single-layer conductive layer 20 is a composite material of PEDOT and PSS, and the hydrophilicity of the conductive layer 20 can be reduced by reducing the mass ratio of hydrophilic PSS in the composite material of PEDOT and PSS. For example, define the mass ratio of PSS to PEDOT in the conductive layer 20 as R3, where the range of R3 is 1

R3

9.9. By adjusting the range of R3, the contact angle of the conductive layer 20 is between 50 degrees and 90 degrees, thereby improving the resistance of the aqueous etchant 40 between the patterned photoresist layer 30 and the conductive layer 20 during the etching process. Penetration speed.

Z1

9.9，Z2的範圍為0<Z2

1。藉由調整Z1、Z2的範圍，使得該導電層20的接觸角介於50度至90度，進而降低水性蝕刻液40在導電層20中的滲透速度，改善水性蝕刻液40的側流問題。 In one embodiment, the single-layer conductive layer 20 is a composite material of PEDOT, PSS, and a hydrophobic polymer material. The hydrophilicity of the conductive layer 20 can be reduced by reducing the mass ratio of the hydrophilic PSS in the conductive layer 20 or adding a hydrophobic polymer material to the PEDOT:PSS. For example, define the mass ratio of PEDOT:PSS:hydrophobic polymer material in the single-layer conductive layer 20 as 1:Z1:Z2, then the range of Z1 is 1

Z1

9.9, the range of Z2 is 0<Z2

1. By adjusting the range of Z1 and Z2, the contact angle of the conductive layer 20 is between 50 degrees and 90 degrees, thereby reducing the penetration speed of the aqueous etching solution 40 in the conductive layer 20 and improving the lateral flow problem of the aqueous etching solution 40 .

In one embodiment, the hydrophobic polymer material may be, but not limited to, polystyrene, polyethylene, polyacetylene or cetyltrimethylammonium bromide ( Cetyltrimethylammonium bromide, CTAB) and so on.

As shown in FIG. 7 , an embodiment of the present invention further provides a conductive structure 100 . The conductive structure 100 includes a substrate 10 and a patterned conductive layer 50 on the substrate 10 . The patterned conductive layer 50 can be formed by the above-mentioned method.

In one embodiment, the conductive layer 20 formed in step S1 includes the hydrophilic conductive film 22 and the weakly hydrophilic conductive film 24, then in step S3, the patterned conductive layer 50 is the hydrophilic conductive film 22 and the weakly hydrophilic conductive film 2.4. The resulting stack after etching.

In another embodiment, the conductive layer 20 formed in step S1 is a single layer, and the single-layer conductive layer 20 is weakly hydrophilic, then in step S3, the patterned conductive layer 50 is the weakly hydrophilic conductive layer 20 The monolayer obtained after etching.

In one embodiment, the patterned conductive layer 50 includes a plurality of touch electrodes 42 and traces 44 electrically connected to the touch electrodes 42 . The touch electrodes 42 include a plurality of touch driving electrodes 422 and a plurality of touch sensing electrodes 424 . The touch driving electrodes 422 and the traces 44 electrically connected to the touch driving electrodes 422 can be prepared by one exposure and one development by the above-mentioned conductive layer patterning method. The touch sensing electrodes 424 and the traces 44 electrically connected to the touch sensing electrodes 424 can be prepared by one exposure and one development by the above-mentioned conductive layer patterning method. The touch driving electrodes 422 , the touch driving electrodes 422 , and the traces 44 can also be prepared by the above-mentioned conductive layer patterning method, respectively.

As shown in FIG. 7 , the plurality of touch driving electrodes 422 are arranged in a plurality of rows along the first direction X, and are arranged in a plurality of columns along the second direction Y. The plurality of touch driving electrodes 422 in each row are sequentially electrically connected to form a string of touch driving electrodes 422 , and the plurality of touch driving electrodes 422 in each column are electrically insulated from each other. The first direction X intersects the second direction Y. The plurality of touch sensing electrodes 424 are arranged in a plurality of rows along the first direction X, and are arranged in a plurality of columns along the second direction Y, and the plurality of touch sensing electrodes 424 in each column are sequentially electrically connected to form a touch sensing electrode 424 strings, the plurality of touch sensing electrodes 424 in each row are electrically insulated from each other.

In another embodiment, the touch driving electrodes 422 and the touch sensing electrodes 424 may also have other shapes and structures. For example, the plurality of touch driving electrodes 422 may extend along the first direction X and extend along the first direction X. Rectangular strips isolated from each other are arranged in two directions Y, and the plurality of touch sensing electrodes 424 may be rectangular strips extending along the first direction X and arranged in isolated rectangular strips along the second direction Y.

In one embodiment, each trace 44 is electrically connected to a series of touch driving electrodes 422 or a series of touch sensing electrodes 424 . The plurality of traces 44 can be bound to a circuit board after being electrically connected to the touch electrodes 42 . The plurality of touch driving electrodes 422 and the plurality of touch sensing electrodes 424 form a mutual capacitive touch sensing structure. When a touch occurs, the capacitive coupling between the touch driving electrodes 422 and the touch sensing electrodes 424 corresponding to the vicinity of the touch point will be affected, resulting in a change in the sensing signal (eg voltage value) related to the mutual capacitance, and further The coordinates of each touch point can be calculated.

In the conductive structure 100, since the patterned conductive layer 50 is prepared by the above method, the formed traces 44 have fine pitch and fine line width.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced. without departing from the spirit and scope of the technical solutions of the present invention.

10: Substrate

20: Conductive layer

22: Hydrophilic conductive film

24: Weak hydrophilic conductive film

30: Patterned photoresist layer

40: Water-based etching solution

Claims (6)

A method for patterning a conductive layer, which is improved by comprising the following steps: forming a conductive layer on the surface of a substrate, the contact angle of the conductive layer being greater than or equal to 50 degrees and less than or equal to 90 degrees; A patterned photoresist layer is formed on the surface of the substrate; and the conductive layer is etched with an aqueous etchant to remove the portion of the conductive layer not covered by the patterned photoresist layer, thereby obtaining a patterned conductive layer wherein, the step of forming the conductive layer includes forming a hydrophilic conductive film on the surface of the substrate and forming a weakly hydrophilic conductive film on the surface of the hydrophilic conductive film away from the substrate; the weakly hydrophilic conductive film is formed The contact angle of the conductive film is greater than or equal to 50 degrees and less than or equal to 90 degrees; the patterned photoresist layer is formed on the surface of the weakly hydrophilic conductive film away from the substrate. The method for patterning a conductive layer according to claim 1, wherein the hydrophilic conductive film and the weakly hydrophilic conductive film are made of poly3,4-ethylenedioxythiophene (PEDOT) and polybenzenesulfonic acid A composite material of vinyl acetate (PSS); define the mass ratio of PSS to PEDOT in the hydrophilic conductive film as R1, define the mass ratio of PSS to PEDOT in the weakly hydrophilic conductive film as R2, and the R2 is less than the R1. The method for patterning a conductive layer according to claim 2, wherein the range of the R1 is 10

R1

100, the R2 range is 1

R2

9.9. A conductive structure comprising a substrate and a patterned conductive layer on the substrate, wherein the patterned conductive layer includes a hydrophilic conductive film on the surface of the substrate and a hydrophilic conductive film on the surface of the substrate The conductive film is a weakly hydrophilic conductive film on the surface of the base material; the contact angle of the weakly hydrophilic conductive film is greater than or equal to 50 degrees and less than or equal to 90 degrees. The conductive structure according to claim 4, wherein the materials of the hydrophilic conductive film and the weakly hydrophilic conductive film are both PEDOT and PSS composite materials, and the quality of PSS and PEDOT in the hydrophilic conductive film is defined The ratio is R1, and the mass ratio of PSS to PEDOT in the weakly hydrophilic conductive film is defined as R2, and the R2 is smaller than the R1. The conductive structure according to claim 4 or 5, wherein the patterned conductive layer includes touch electrodes and traces electrically connected to the touch electrodes.

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