Brown etching method for circuit board structure and brown etching solution

Abstract

The present invention discloses a browning micro-etching method and browning micro-etching solution for a circuit board structure. The browning micro-etching solution comprises a browning liquid, an acidic liquid, and a micro-etching solution. The browning liquid is used for browning the circuit board structure, so that two passivation layers are formed on two opposite side surfaces of the circuit board structure, and based on the total weight of the browning micro-etching solution being 100wt%, the content of the browning liquid is between 4wt% and 6wt%. The acidic liquid can maintain the browning micro-etching solution in a micro-etching environment, the content of the acidic liquid is between 17wt% and 23wt%, and the pH value of the micro-etching environment is between 3 and 8. The micro-etching solution is used for micro-etching the two passivation layers, the content of the micro-etching solution is between 3wt% and 4wt%, and the micro-etching solution forms a micro-etched surface with an average roughness of between 0.20 and 0.23 on each passivation layer. After the browning reaction and micro-etching reaction, the average roughness of the micro-etched surface of the circuit board structure can be reduced to reduce the loss generated during signal transmission.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of brown methods, especially a kind of brown microetching method and brown microetching liquor of circuit board structure. BACKGROUND

[0002] In the existing brown liquor, when increasing copper surface roughness, the loss of signal transmission also accompanies with the increase of copper surface roughness and promotes. Therefore, the present application is believed to improve the above-mentioned defects, and finally proposes the present application with reasonable design and effective improvement of the above-mentioned defects by dint of scientific principles. SUMMARY

[0003] The present application provides a kind of brown microetching method and brown microetching liquor of circuit board structure to effectively improve the defects that can be generated by the existing brown liquor.

[0004] The present application discloses a kind of brown microetching method of circuit board structure, which comprises: a pre-step, providing brown microetching liquor, the brown microetching liquor includes brown liquid, acidic liquid and microetching liquid, wherein, based on the total weight of the brown microetching liquor is 100wt%, the content of the brown liquid is between 4wt% and 6wt%, the content of the acidic liquid is between 17wt% and 23wt%, and the content of the microetching liquid is between 3wt% and 4wt%; Brown step, the circuit board structure is immersed in the brown microetching liquor, to carry out brown reaction on the circuit board structure by the brown liquid, and two passivation layers are formed on the two side surfaces of the circuit board structure opposite to each other;And microetching step, the circuit board structure is continuously immersed in the brown microetching liquor, so that the microetching liquid carries out microetching reaction on two passivation layers to form two microetched surfaces;Wherein, after the microetching step, the microetching liquid forms a microetched surface with an average roughness (Ra) of between 0.20 microns and 0.23 microns on each passivation layer of the circuit board structure;Wherein, after the microetching step, the microetched surface of each passivation layer defines a specific surface area ratio, and the specific surface area ratio is between 1.1 and 1.2.

[0005] Optionally, the pre-step further comprises an acid washing step, and the circuit board structure is subjected to acid washing with an acidic cleaning agent;Wherein, the acidic cleaning agent comprises at least one of sulfuric acid aqueous solution and sodium persulfate aqueous solution.

[0006] Optionally, the pre-step further comprises an alkaline cleaning step, and the circuit board structure is subjected to alkaline cleaning with an alkaline cleaning agent;Wherein, based on the total weight of the alkaline cleaning agent is 100wt%, the alkaline cleaning agent comprises 25wt% to 55wt% of sodium hydroxide.

[0007] Optionally, the pre-step further comprises a pre-soaking step of soaking the circuit board structure with a pre-soaking agent; wherein the pre-soaking agent comprises 10wt% to 35wt% of isopropyl alcohol based on 100wt% of total weight of the pre-soaking agent, and the pre-soaking agent is capable of activating the passivation layer of the circuit board structure.

[0008] Optionally, in the brown-oxidation step, the circuit board structure is soaked in the brown-oxidation micro-etching solution at a brown-oxidation temperature for a brown-oxidation time; wherein the brown-oxidation temperature is between 37℃ to 45℃, and the brown-oxidation time is between 45 seconds to 95 seconds.

[0009] Optionally, in the micro-etching step, the circuit board structure is soaked in the brown-oxidation micro-etching solution at a micro-etching temperature for a micro-etching time; wherein the micro-etching temperature is between 20℃ to 45℃, and the micro-etching time is between 5 seconds to 35 seconds.

[0010] The present disclosure also discloses a brown-oxidation micro-etching solution, comprising: a brown-oxidation liquid for performing a brown-oxidation reaction on a circuit board structure to form two passivation layers on two opposite side surfaces of the circuit board structure, and the content of the brown-oxidation liquid is between 4wt% to 6wt% based on 100wt% of total weight of the brown-oxidation micro-etching solution; an acidic liquid capable of maintaining the brown-oxidation micro-etching solution in a micro-etching environment, and the content of the acidic liquid is between 17wt% to 23wt% based on 100wt% of total weight of the brown-oxidation micro-etching solution, wherein the pH value of the micro-etching environment is between 3 to 8; a micro-etching liquid for micro-etching the two passivation layers, and the content of the micro-etching liquid is between 3wt% to 4wt% based on 100wt% of total weight of the brown-oxidation micro-etching solution; wherein the micro-etching liquid forms a micro-etching surface with an average roughness (Ra) between 0.20 microns to 0.23 microns on each of the passivation layers of the circuit board structure.

[0011] Optionally, the brown-oxidation liquid of the brown-oxidation micro-etching solution is composed of at least one of sulfuric acid and benzotriazole, and the content of sulfuric acid is between 3wt% to 13wt% and the content of benzotriazole is between 5wt% to 25wt% based on 100wt% of total weight of the brown-oxidation liquid.

[0012] Optionally, the acidic liquid of the brown-oxidation micro-etching solution is composed of at least one of sulfuric acid and nitric acid, and the ratio of the sulfuric acid to the nitric acid is between 1:3 to 3:5.

[0013] Optionally, the micro-etching liquid of the brown-oxidation micro-etching solution is an aqueous hydrogen peroxide solution, and the content of hydrogen peroxide is between 30wt% to 40wt% based on 100wt% of total weight of the micro-etching liquid.

[0014] In summary, the brown micro-etching method and the brown micro-etching solution for the circuit board structure disclosed in the embodiments of the present application can reduce the average roughness of the micro-etched surface after the brown reaction and the micro-etching reaction, thereby reducing the loss generated during signal transmission, by the design of "the content of the brown liquid is between 4wt% and 6wt%, the content of the acidic liquid is between 17wt% and 23wt%, and the content of the micro-etching liquid is between 3wt% and 4wt% based on the total weight of the brown micro-etching solution being 100wt%", and "the second surface roughness is not more than 0.23".

[0015] For a more complete understanding of the features and technical content of the present application, please refer to the following detailed description of the present application and the accompanying drawings, but these descriptions and drawings are only used to illustrate the present application, and do not limit the scope of protection of the present application in any way. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The brown micro-etching method for the circuit board structure of the embodiments of the present application.

[0017] Figure 2 The circuit board structure after the brown micro-etching method of the embodiments of the present application. DETAILED DESCRIPTION

[0018] The following is to illustrate the embodiments of the present application disclosed in relation to "the brown micro-etching method and the brown micro-etching solution for the circuit board structure" through specific embodiments, and those skilled in the art can understand the advantages and effects of the present application from the content disclosed in the present description. The present application can be implemented or applied through other different embodiments, and each detail in the present description can be modified and changed in various ways based on different viewpoints and applications without departing from the concept of the present application. In addition, the drawings of the present application are only simple schematic illustrations, not the depiction of actual dimensions, and the prior declaration is hereby made. The following embodiments will further illustrate the related technical content of the present application in detail, but the disclosed content is not used to limit the scope of protection of the present application.

[0019] It should be understood that although the terms "first", "second", "third" and the like may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are mainly used to distinguish one component from another component, or one signal from another signal. In addition, the term "or" used herein may include any one or more combinations of the associated listed items.

[0020] [Brown micro-etching solution]

[0021] The present embodiment discloses a brown micro-etching solution which can be applied to a circuit board structure 1, for example, the brown micro-etching solution can be used to provide brown reaction and micro-etching reaction on two side surfaces of the circuit board structure 1, and the brown micro-etching solution in the present embodiment can effectively reduce the roughness of the side surfaces after the brown reaction and micro-etching reaction on the side surfaces of the circuit board structure 1 to increase the transmission efficiency of signals.

[0022] In detail, the brown micro-etching solution comprises a brown solution, an acidic solution, and a micro-etching solution. In the present embodiment, the content of the brown solution is between 4wt% and 6wt% based on the total weight of the brown micro-etching solution being 100wt%, and the brown solution is composed of at least one of sulfuric acid and benzotriazole. In addition, the brown micro-etching solution can further comprise 67wt% to 76wt% of water based on the total weight of the brown micro-etching solution being 100wt%, but the present application is not limited thereto.

[0023] Further, the content of sulfuric acid is between 3wt% and 13wt% and the content of benzotriazole is between 5wt% and 25wt% based on the total weight of the brown solution being 100wt%, but the present application is not limited thereto.

[0024] It is worth mentioning that the brown solution is used for the brown reaction of the circuit board structure 1, so that two passivation layers 2 are formed on two side surfaces of the circuit board structure 1 opposite to each other (as shown in the following figure): Figure 2 That is, when the circuit board structure 1 is immersed in the brown micro-etching solution, the brown solution in the brown micro-etching solution will perform brown reaction on two side surfaces of the circuit board structure 1 to form two passivation layers 2.

[0025] In detail, in the brown reaction, when the circuit board structure 1 is immersed in the brown micro-etching solution, the organic matter in the brown micro-etching solution will be complexed with copper on two side surfaces of the circuit board structure 1 to form two passivation layers 2.

[0026] In the present embodiment, the content of the acidic solution is between 17wt% and 23wt% based on the total weight of the brown micro-etching solution being 100wt%. The acidic solution is composed of at least one of sulfuric acid and nitric acid, and the ratio of the sulfuric acid to the nitric acid is between 1:3 and 3:5, which can be 2:1, but the present application is not limited thereto.

[0027] Further, the acidic liquid can maintain the brown micro-etching solution in a micro-etching environment, and the pH value of the micro-etching environment is between 3 and 8, or between 3 and 6.5; that is, when the circuit board structure 1 is immersed in the brown micro-etching solution, the acidic liquid in the brown micro-etching solution can provide the circuit board structure 1 with a brown reaction or a micro-etching reaction in the acidic environment.

[0028] In the present embodiment, the content of the micro-etching liquid is between 3 wt% and 4 wt% based on the total weight of the brown micro-etching solution being 100 wt%. The micro-etching liquid is hydrogen peroxide solution, and the content of hydrogen peroxide is between 30 wt% and 40 wt%, or 35 wt% based on the total weight of the hydrogen peroxide solution being 100 wt%, but the present application is not limited thereto.

[0029] Further, the micro-etching liquid is used to provide the two passivation layers 2 of the circuit board structure 1 with a micro-etching reaction, and the two passivation layers 2 after the micro-etching reaction form a micro-etching surface 3 with an average roughness between 0.20 and 0.23 (as shown in Figure 2 ).

[0030] That is, when the circuit board structure 1 is continuously immersed in the brown micro-etching solution, the micro-etching liquid will react with the two passivation layers 2 to form the micro-etching surface 3, and the circuit board structure 1 can be browned and etched with the same solution, that is, the brown micro-etching solution.

[0031] As described above, the circuit board structure 1 can form the micro-etching surface 3 with an average roughness between 0.20 and 0.23 on the surface of the circuit board structure 1 through the content relationship between the brown liquid and the micro-etching liquid in the brown micro-etching solution; and based on the average roughness of the micro-etching surface 3 being between 0.20 and 0.23, the loss caused by the signal transmission of the circuit board structure 1 can be improved, and the transmission efficiency of the signal can be improved.

[0032] [Brown micro-etching method for circuit board structure]

[0033] Please refer to Figure 1 The present embodiment provides a brown micro-etching method for a circuit board structure, which comprises steps S110 to S130. It must be pointed out that the order of each step described in the present embodiment and the actual operation mode can be adjusted as needed, and is not limited to the description in the present embodiment.

[0034] The step S110 is a pre-step, which comprises providing a brown micro-etching solution, the brown micro-etching solution comprising a brown liquid, an acidic liquid and a micro-etching liquid, wherein, based on the total weight of the brown micro-etching solution being 100 wt%, the content of the brown liquid is between 4 wt% and 6 wt%, the content of the acidic liquid is between 17 wt% and 23 wt%, and the content of the micro-etching liquid is between 3 wt% and 4 wt%.

[0035] In detail, the brown liquid is composed of at least one of sulfuric acid and benzotriazole, and, based on the total weight of the brown liquid being 100 wt%, the content of sulfuric acid is between 3 wt% and 13 wt%, and the content of benzotriazole is between 5 wt% and 25 wt%, but the present application is not limited thereto.

[0036] The acidic liquid is composed of at least one of sulfuric acid and nitric acid, and the ratio of the sulfuric acid to the nitric acid is between 1:3 and 3:5, which can be 2:1, but the present application is not limited thereto.

[0037] In addition, the acidic liquid can maintain the brown micro-etching solution in an acidic environment, and the pH value of the acidic environment is between 3 and 8, which can be between 3 and 6.5; that is, when the circuit board structure 1 is soaked in the brown micro-etching solution, the acidic liquid in the brown micro-etching solution can provide the circuit board structure 1 with a brown reaction or a micro-etching reaction in the acidic environment.

[0038] The micro-etching liquid is hydrogen peroxide aqueous solution, and, based on the total weight of the hydrogen peroxide aqueous solution being 100 wt%, the content of hydrogen peroxide is between 30 wt% and 40 wt%, which can be 35 wt%, but the present application is not limited thereto.

[0039] The step S110 further comprises steps S111 to S113, but the present application is not limited thereto; for example, in other embodiments of the present application, steps S111 to S113 can also be excluded.

[0040] The step S111 comprises an acid pickling step of acid pickling the circuit board structure 1 with an acidic cleaner, and the acidic cleaner comprises at least one of a sulfuric acid aqueous solution and a sodium persulfate aqueous solution, but the present application is not limited thereto.

[0041] In detail, the acidic cleaner can be used to clean dirt on two side surfaces of the circuit board structure 1 opposite to each other, and the content of sulfuric acid in the sulfuric acid aqueous solution is between 8wt% and 12wt% based on the total weight of the sulfuric acid aqueous solution being 100wt%, and the content of sodium persulfate in the sodium persulfate aqueous solution is between 2wt% and 4wt% based on the total weight of the sodium persulfate aqueous solution being 100wt%, but the present application is not limited thereto.

[0042] The step S112 comprises an alkaline cleaning step of cleaning the circuit board structure 1 with an alkaline cleaner. That is, the alkaline cleaner can be used to clean dirt on the side surfaces of the circuit board structure 1.

[0043] In addition, the alkaline cleaner is a sodium hydroxide aqueous solution, and the sodium hydroxide aqueous solution contains 25wt% to 55wt% of sodium hydroxide based on the total weight of the sodium hydroxide aqueous solution being 100wt%, but the present application is not limited thereto.

[0044] The step S113 comprises a pre-soaking step of soaking the circuit board structure 1 with a pre-soaking agent.

[0045] In detail, the pre-soaking agent is an isopropyl alcohol aqueous solution, and the isopropyl alcohol aqueous solution contains 10wt% to 35wt% of isopropyl alcohol based on the total weight of the isopropyl alcohol aqueous solution being 100wt%, but the present application is not limited thereto.

[0046] In addition, by soaking the side surfaces of the circuit board structure 1 in the pre-soaking agent, the passivation layer 2 of the circuit board structure 1 can be activated, further accelerating the reaction of the brownification step.

[0047] The step S120 is a brownification step, which comprises soaking the circuit board structure 1 in the brownification micro-etching solution to brownify the circuit board structure 1 by the brownification liquid, and forming two passivation layers 2 on two side surfaces of the circuit board structure 1 opposite to each other (as shown in the following figure). Figure 2 ).

[0048] That is, when the circuit board structure 1 is soaked in the brownification micro-etching solution, the brownification liquid in the brownification micro-etching solution will brownify the two side surfaces of the circuit board structure 1 to form two passivation layers 2.

[0049] In detail, the brownification reaction will immediately produce etching effect while the circuit board structure 1 is soaked in the brownification micro-etching solution, and the organic matter in the brownification micro-etching solution will complex with copper on the two side surfaces of the circuit board structure 1 to form two passivation layers 2.

[0050] It is worth mentioning that, in the brown-etching step, the circuit board structure 1 is immersed in the brown-etching solution at a brown-etching temperature for a brown-etching time. The brown-etching temperature is between 37°C and 45°C, and the brown-etching time is between 45 seconds and 95 seconds, but the present application is not limited thereto.

[0051] That is, in the brown-etching step, the circuit board structure 1 is immersed in the brown-etching solution at a temperature between 37°C and 45°C for 45 seconds to 95 seconds, so that the brown-etching solution can form two passivation layers 2 on the two opposite side surfaces of the circuit board structure 1.

[0052] The step S130 is an etching step, which includes continuously immersing the circuit board structure 1 in the brown-etching solution so that the etching solution etches the two passivation layers 2.

[0053] That is, when the circuit board structure 1 is continuously immersed in the brown-etching solution, the etching solution is used to provide the two passivation layers 2 of the circuit board structure 1 with etching reactions, and the two passivation layers 2 after the etching reactions form etching surfaces 3 with an average roughness between 0.20 and 0.23 (as shown in FIG. 2). Figure 2

[0054] It is worth mentioning that, in the etching step, the circuit board structure 1 is immersed in the brown-etching solution at an etching temperature for an etching time. The etching temperature is between 20°C and 45°C, and the etching time is between 5 seconds and 35 seconds.

[0055] That is, in the etching step, the circuit board structure 1 is immersed in the brown-etching solution at a temperature between 20°C and 45°C for 5 seconds to 35 seconds, so that the etching solution in the brown-etching solution can etch the two passivation layers 2 of the circuit board structure 1 to form the etching surfaces 3.

[0056] It is worth mentioning that, after the etching step, the etching solution forms the etching surfaces 3 with an average roughness (Ra) between 0.20 microns and 0.23 microns on each passivation layer 2 of the circuit board structure 1.

[0057] In addition, after the etching step, the etching surfaces 3 of each passivation layer 2 define a specific surface area ratio, and the specific surface area ratio is between 1.1 and 1.2.

[0058] Table 1 shows the test results of the example and the comparative example

[0059] ​

[0060] According to the test results, the brown micro-etching solution used in Example 1 has lower average roughness (Ra), cross-sectional curve average (Pz), and specific surface area ratio than Comparative Example 1 at the same micro-etching amount.

[0061] [Technical effects of the embodiment of the present application]

[0062] In summary, the brown micro-etching method and the brown micro-etching solution of the circuit board structure 1 can reduce the average roughness of the micro-etched surface 3 after the brown reaction and the micro-etching reaction, thereby reducing the signal transmission loss, by designing the content of the brown solution to be between 4wt% and 6wt%, the content of the acidic solution to be between 17wt% and 23wt%, and the content of the micro-etching solution to be between 3wt% and 4wt% based on the total weight of the brown micro-etching solution being 100wt%, and the second surface roughness being between 0.20 and 0.23.

[0063] The above description is only the preferred embodiments of the present application, and is not intended to limit the protection scope of the present application. Any equivalent changes and modifications made according to the claims of the present application shall be within the protection scope of the present application.

Claims

1. A browning micro-etching method for a circuit board structure, characterized in that: The browning micro-etching method for the circuit board structure includes: A preliminary step of providing a browning micro-etching solution, wherein the browning micro-etching solution comprises a browning liquid, an acidic liquid, and a micro-etching solution, wherein, based on the total weight of the browning micro-etching solution being 100 wt%, the content of the browning liquid is between 4 wt% and 6 wt%, the content of the acidic liquid is between 17 wt% and 23 wt%, and the content of the micro-etching solution is between 3 wt% and 4 wt%; a browning step, immersing the circuit board structure in the browning micro-etching solution to cause a browning reaction on the circuit board structure by the browning solution, and forming two passivation layers on two opposite side surfaces of the circuit board structure; and A micro-etching step, wherein the circuit board structure is continuously immersed in the brown micro-etching solution, so that the micro-etching solution micro-etches the two passivation layers to form two micro-etched surfaces; wherein, after the micro-etching step, the micro-etching liquid forms a micro-etched surface with an average roughness Ra between 0.20 μm and 0.23 μm on each of the passivation layers of the circuit board structure; Wherein, after the micro-etching step, the micro-etched surface of each of the passivation layers is defined with a specific surface area ratio, and the specific surface area ratio is between 1.1 and 1.

2.

2. The browning micro-etching method for a circuit board structure according to claim 1, characterized in that: The pre-step further includes an acid cleaning step, wherein the circuit board structure is acid cleaned with an acidic cleaning agent; wherein the acidic cleaning agent includes at least one of a sulfuric acid aqueous solution and a sodium persulfate aqueous solution.

3. The browning micro-etching method for a circuit board structure according to claim 1, characterized in that: The pre-step further includes an alkaline cleaning step, wherein the circuit board structure is alkaline cleaned with an alkaline cleaner; wherein, based on the total weight of the alkaline cleaner being 100 wt%, the alkaline cleaner contains 25 wt% to 55 wt% of sodium hydroxide.

4. The browning micro-etching method for a circuit board structure according to claim 1, characterized in that: The pre-step further includes a pre-soaking step, in which the circuit board structure is soaked with a pre-soak; wherein, based on the total weight of the pre-soak being 100wt%, the pre-soak contains 10 wt% to 35 wt% of isopropyl alcohol, and the passivation layer of the circuit board structure can be activated by the pre-soak.

5. The browning micro-etching method for a circuit board structure according to claim 1, characterized in that: In the browning step, the circuit board structure is immersed in the browning micro-etching solution at a browning temperature for a browning time; wherein the browning temperature is between 37° C. and 45° C., and the browning time is between 45 seconds and 95 seconds.

6. The browning micro-etching method for a circuit board structure according to claim 1, characterized in that: In the micro-etching step, the circuit board structure is immersed in the brown micro-etching solution at a micro-etching temperature for a micro-etching time; wherein the micro-etching temperature is between 20° C. and 45° C., and the micro-etching time is between 5 seconds and 35 seconds.

7. A browning micro-etching solution, characterized in that: The browning micro-etching solution comprises: A browning solution for browning the circuit board structure to form two passivation layers on two opposite side surfaces of the circuit board structure, wherein the content of the browning solution is between 4 wt% and 6 wt% based on the total weight of the browning micro-etching solution being 100 wt%; An acidic liquid capable of maintaining the browning micro-etching solution in a micro-etching environment, wherein the content of the acidic liquid is between 17 wt % and 23 wt % based on 100 wt % of the total weight of the browning micro-etching solution, wherein the pH value of the micro-etching environment is between 3 and 8; A micro-etching solution is used to micro-etch the two passivation layers, and based on the total weight of the brown micro-etching solution being 100wt%, the content of the micro-etching solution is between 3wt% and 4wt%; wherein the micro-etching solution forms a micro-etched surface with an average roughness Ra between 0.20μm and 0.23μm on each of the passivation layers of the circuit board structure.

8. The browning micro-etching solution according to claim 7, characterized in that: The browning liquid of the browning micro-etching solution is composed of at least one of sulfuric acid and benzotriazole. Based on the total weight of the browning liquid being 100 wt%, the content of sulfuric acid is between 3 wt% and 13 wt%, and the content of benzotriazole is between 5 wt% and 25 wt%.

9. The browning micro-etching solution according to claim 7, characterized in that: The acidic liquid of the browning micro-etching solution is composed of at least one of sulfuric acid and nitric acid, and the ratio of the sulfuric acid to the nitric acid is between 1:3 and 3:

5.

10. The browning micro-etching solution according to claim 7, characterized in that: The micro-etching solution of the browning micro-etching solution is a hydrogen peroxide aqueous solution, and based on the total weight of the micro-etching solution being 100 wt %, the content of hydrogen peroxide is between 30 wt % and 40 wt %.

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