TW201729656A - A method for modification of laminates used to manufacture printed circuit boards - Google Patents

Abstract

The present invention relates to the method for modification of laminates used to manufacture printed circuit boards. The present invention allows to use the laminates used in the subtractive method for industrial manufacturing of printed circuit boards in semi-additive and additive processes. Modification of laminates used to manufacture printed circuit boards consist in using two processes: 1. Adding to the resin comprising the laminate a catalytic substance that is a photoactive titanium dioxide (TiO2) complex oxides in the amount of at least 10% by weight as compared to the resin weight, preferably from 10% to 40% by weight. 2. Development of the surface of the laminate manufactured in the first process to at least 150%.

Description

Modification method for manufacturing laminate used in printed circuit boards

The present invention relates to a method of modifying a laminate used in the manufacture of a printed circuit board, which allows the use of a laminate for use in a printed circuit board by a removal process for use in a semi-additive or additive process to produce a printed circuit board .

Many companies and organizations have long sought to develop a way to fabricate printed circuit boards in a semi-additive or additive process to replace the current manufacture of printed circuit boards by subtractive methods. The purpose of these studies is to The typical drawbacks encountered in the fabrication of laminates used in printed circuit boards by the removal process are improved. The basic weakness of this removal method is as follows: the dielectric material covered with copper is used, and during the preparation process of the circuit board, most of the copper is etched; -- photoresist and metal resistance are required; and -- immersed in Expensive palladium salt solution.

In the prior art removal process, the photosensitive cover on the treated printed circuit layer or the copper foil of the printed circuit board is exposed to light during the manufacture of a printed circuit layer or a printed circuit board. The exposure process is performed after the mask is applied to the treated printed circuit layer or printed circuit board, the mask enables image formation on the photosensitive layer of the printed component, and the printed components are processed and processed therein. The circuit layer or printed circuit board is etched under a process It is saved.

Polish Patent No. PL189558 discloses "a method of directly plating a dielectric, in particular a method of directly plating a hole in a printed circuit board" for removing electroplating of a printed circuit board. The printed circuit board is made of a glass epoxy laminate, which is covered with copper on both sides and has a drilled hole. According to this method, the printed circuit board is subjected to an electrochemical degreasing process and then treated in acetone. Subsequently, the hole of the printed circuit board was treated at 60 ° C for 5 minutes with a solution of a cleaning treatment agent 3223 containing a cationic surfactant prepared by Shipley. This copper foil was then micro-etched in a solution. This solution contained 100 ml/l of concentrated sulfuric acid and 20 ml/30% hydrogen peroxide (H2O2). Thereafter, the printed circuit board is covered with a palladium activator. The palladium activator comprises 50 g/l stannous chloride, 1 g/l palladium chloride, and 150 ml/l concentrated hydrochloric acid. This activation process was carried out at 60 ° C for 5 to 25 minutes, after which an acceleration process was carried out, i.e., the printed circuit board was immersed in a 1 M sulfuric acid solution for 5 to 10 minutes. Subsequently, the thus prepared printed circuit board is placed in an electrolytic bath for electroplating. The electrolytic cell contained: 80 g/l of copper sulfate (CuSO ₄ * 5H ₂ O), 180 g/l of concentrated sulfuric acid, and 0.1 ml/l of concentrated hydrochloric acid (HCl).

In the art of manufacturing a laminate for a printed circuit board, a substrate having catalytic activity or light catalyzing activity is not used in such processes. Such processes using catalyzed or photocatalytic activity are economically more advantageous and provide a better prospect for their application. These processes require a lot less process operation and are more environmentally friendly. At present, a process which can use a catalyzing activity or a light catalyzing activity has not been developed, which can be used in industrial production in a satisfactory manner.

U.S. Patent No. 7,468, 175, "Highly Sensitive Titanium Dioxide and Its Process", and U.S. Patent No. 8,012,451, "Highly Sensitive Titanium Dioxide and Processes", disclose a high level photosensitive titanium dioxide composition. These methods include the steps of providing: a titanium dioxide composite such as titanium trichloride or titanium tetrachloride; an oxygen containing gas such as air and hydrogen. The concentration of this hydrogen is stoichiometrically excess and H ₂ :O ₂ is from 2.02:1 to 2.61:1. In the method of the above patent, the titanium chloride composite is burned in the atmosphere of oxygen and hydrogen of an oxygen-containing gas to form a plurality of ultrafine (or so-called nano-sized) particles. The titanium dioxide-containing particles produced according to the above patent are rutile particles and anatase particles having a magnetic susceptibility value of at least 0.8 x 10 ^-6 cm ³ /g at 300 K and a weight percentage of rutile of at least 30%, the remainder being Anatase. The magnetic susceptibility value at 300K can range between 0.8x10 ^-6 cm ³ /g and 2.4x10 ^-6 cm ³ /g. The very high paramagnetic susceptibility value of this composition shows its high photocatalytic activity, for example, the sensitivity at room temperature is 1.4-3.0 mg/ml min m ² , which is greater than the photosensitivity provided by conventional industrial TiO ₂ pigment products. An order of magnitude, this traditional industrial sensitivity at room temperature is typically 2.5-3.0 x 10 ^-5 mg/ml min m ² .

The process of this conventional laminate and printed circuit board includes a previously known removal process that does not produce a high quality printed circuit board that is labor intensive and expensive.

The method for modifying the laminate used in the manufacture of a printed circuit board according to the present invention is focused on: adding a photocatalyst based on highly photosensitive TiO ₂ to a thermosetting epoxy resin and/or acrylic acid and/or phenolic resin or the like. Thermosetting resin. The photocatalyst has a molecular formula of Me _n O _m (where n, m are natural numbers, Me is a metal, which is selected from one of Ti, Si, Zn, Bi, and W, and in the present invention, Me is Ti, n =1, m=2), which is 10% to 40% by weight based on the weight of the resin. Depending on the requirements of this removal process, a photocatalyst is added to the thermosetting resin during the manufacture of the laminate. The photocatalyst to which the TiO ₂ -based photocatalyst is added is Me _n O _m (where n, m are natural numbers, Me is a metal, which is selected from one of Ti, Si, Zn, Bi, and W, In the present invention, Me is Ti, n = 1, m = 2), and the weight percentage is preferably from 15% to 20% by weight based on the weight of the resin. Then, the thermosetting resin having the added photocatalyst or other additives such as an accelerator and a curing agent is subjected to a homogenisation process. The additive added to the thermosetting resin is a highly photosensitive TiO ₂ comprising a plurality of nanoparticles, and comprising TiO ₂ , and a secondary titanium oxide having other metal oxides. This homogenized mixture is then applied to a tape made of fibrous material. This tape is preferably a mat of glass material or other material felt. Then, the entire structure is subjected to a press molding process, which preferably uses a compression roller system. Subsequently, the surface-expanding process of the finished cured laminate is at least 150.0%. The purpose of this surface development process is to enhance the adhesion of copper to the laminate. Depending on the capabilities of the manufacturer, the surface development process of the laminate is preferably carried out using chemical, physical, or physical/chemical methods.

Then, the thus-prepared laminate is subjected to a process of a printed circuit board by a semi-additive method or an additive method.

In this semi-additive method, the process of this printed circuit board is carried out in the following manner.

The laminate is cut into pieces and has a drilled hole, and the entire surface of the laminated sheet is covered with a copper layer of 1.5 to 2.0 μm thick; The inner surfaces of the drilled holes were covered with a copper layer of 1.5 to 2.0 μm thick.

According to the semi-additive method, the above process is preferably carried out in the following two ways.

In the first method of the semi-additive process, the sheet laminate is subjected to an activation process by a palladium salt, and then subjected to a drying process. After drying, the cut into sheet laminates were placed in a chemical copper bath for 60 to 90 minutes. In this chemical copper bath, the entire surface of the cut sheet is covered with a copper layer of 1.5 to 2.0 μm thick. This same copper layer is then applied over the entire inner surface of the drilled holes.

Cut this into a laminate to have an image-patterned photoresist (photo The resistor is covered and then placed in a chemical copper bath for electroplating, at which time a printed circuit trace of the desired size is fabricated and the drilled holes are covered with copper.

In the second method of the semi-additive process, the dielectric surface and the inner surface of the drilled hole are activated by immersing the cut into a sheet laminate in the activation solution. The activation solution preferably comprises the following components: copper sulfate (CuSO ₄ * 5H ₂ O) used in an amount of 10% to 12% by weight; ethylenediaminetetraacetic acid (Trilon B) used in an amount of 20% to 25% % by weight; sodium hydroxide (NaOH), used in an amount of 10% to 12% by weight; α,α'-dipyridyl (α,α'-dipyridil), used in an amount of 10 mg / l; Potassium ferricyanide (K ₃ (Fe(CN) ₆ ), used in an amount of 30 mg/l; formalin, used in an amount of 10 mg/l; solution temperature of about 65 ° C ± 5 ° C: and The pH of the solution was 12.5 to 13.0.

After drying, an exposure process is performed to expose the entire laminate to ultraviolet radiation. Therefore, copper particles are formed in the laminate and the drill according to the following reaction formula: TiO ₂ → UV → = TiO ₂ ^-1 + Cu ⁺¹ → TiO ₂ + Cu

This exposure process is preferably carried out using laser light for selective exposure without the use of a mask.

This treated ionized copper is converted to copper in metallic form. Such metal form particles become the reaction center during the chemical copper bath, and this electroless plating is performed for 60 to 120 minutes. Thus, a laminated board having a surface and a drilled hole covered with a copper layer of 1.5 to 2.0 μm thick was obtained. According to go

The substrate prepared by this method is used for the production of a printed circuit board.

In this additive method, the process of the printed circuit board is carried out by cutting the laminated board having the drilled hole according to the present invention into a piece; then, cutting the surface of the laminated board into a laminated board and a laminated board The borehole is immersed in a copper salt bath for activation: this is cut into a sheet laminate to be dried by the activated surface, and after drying, the surface cut into the laminated sheet and the bore of the laminate are exposed to ultraviolet radiation.

Due to the above activities, a catalytic center is formed on the surface of the laminated plate and the inner surface of the bore of the laminated plate during the chemical copper bath. After exposing it to ultraviolet radiation, a pattern is formed on the surface of the laminate, and then the pattern is covered with a copper layer of a desired thickness by immersing it in a chemical copper bath. This exposes the laminate to ultraviolet radiation for a period of about 15 to 20 seconds.

This exposure process is preferably carried out using laser light for selective exposure.

Traces of the printed circuit are applied to the dielectric substrate of the laminate produced in accordance with the present invention using an additive process and a semi-additive process. This method is more economical and easy to implement, and can obtain a printed circuit board of high quality and fine pattern, which occupies less space and achieves higher packing density; and the method is more environmentally friendly.

The key to modifying this laminate for manufacturing printed circuit boards is the following two processes:

1. A catalytic material is added to the laminate comprising the resin. The catalytic material is an active titanium dioxide (having a molecular formula of Me _n O _m , wherein n, m are natural numbers, Me is a metal, which is selected from one of Ti, Si, Zn, Bi, and W, in the present invention Me is a composite oxide of Ti, n = 1, m = 2), which is used in an amount of at least 10% by weight based on the weight of the resin. The composite oxide of the photoactive titanium oxide added is preferably used in an amount of 10% to 40% by weight based on the weight of the resin.

2. Expand the surface of the laminate produced in the first process to at least 150% of its surface before deployment.

In order to obtain the adhesion of the required copper to the dielectric substrate, photoselective plating can be used. This photoselective plating is a process in which metal is deposited only on a section exposed to the dielectric surface of the light to produce a metal forming reaction. This photoselective electroplating is based on the principle of absorbing light during exposure of the intermediate dielectric material to produce a catalytic center; depositing a metal on a nucleation seed during later electroless plating. Such a process results in the formation of a pattern on the surface of a printed circuit board composed of metal particles.

Therefore, when the dielectric substrate used herein meets two conditions, the formation process of the printed circuit board can be performed. Among them, the laminated board for manufacturing the basic components of the printed circuit board is properly prepared. The laminate used to make the printed circuit board should be subjected to an additional dual rail process during its formation. In the prior art, during the formation of a dielectric laminate or other material, it is necessary to add a component having a relatively catalytic or photocatalytic activity to achieve a proper development of the surface of the laminate later.

Photosensitive titanium dioxide or a similar titanium oxide (formed in US Pat. No. 8,012,451), and a composite oxide of TiO ₂ (Me _n O _m ), all of which have comparable catalytic activity. Examples of such photoactive results are shown in Table 1. Table 1 provides the physical and chemical properties of the photocatalyst-dielectric material fillers developed in the present invention.

Table 1

Table 1 shows the system of composite oxides SiO ₂ -TiO ₂ , ZnO-TiO ₂ , WO ₃ -TiO ₂ , Bi ₂ O ₃ -TiO ₂ . Wherein, the weight percentage of SiO ₂ is greater than or equal to 30%, the weight percentage of ZnO is 50%, the weight percentage of WO ₃ is 10%, and the weight percentage of Bi ₂ O ₃ is 10%. These composite oxides have suitable photoactivity and dispersion, and have been demonstrated to be useful as photosensitive dielectric components for laminates. By placing the crushed catalyst in the dielectric, the dielectric can be made photosensitive, having the photoactive values listed in Table 2, and thus allowing Pd ²⁺ , Fe ²⁺ , Ni ^{2 +} , Cu ²⁺ ions react to form an active center as electroless plating.

Table 2

Testing of the polymer component of the TiO ₂ -based photocatalyst showed that 15-20% by weight of the laminate having the minimum photoactivity of 1.0 x 10 ^-1 was sufficient to form a plating pattern.

The second condition for obtaining adhesion of the copper to the substrate is that the surface of the photosensitive member laminate is unfolded. The unfolding process of the surface of the laminate is preferably performed by chemical, physical, or physical/chemical methods depending on the capabilities of the manufacturer.

The polymer component containing TiO ₂ as the main photocatalyst is applied to the unwinding process of the surface of the laminate, so that the laminate can be prepared, which can be completely dedicated to the industrial semi-additive and additive method to manufacture a printed circuit board.

The method of modifying the laminate used in the manufacture of a printed circuit board according to the present invention has the advantage that metal electrolyte deposition by a brine solution can be dispensed with, and can have many important uses. Such uses include: surface plating of a dielectric material comprising an additive, the additive Catalytic or photocatalytic activity. In this method according to the invention, photoselective electroplating is used. Therein, the metal is deposited only on a section of the surface of the dielectric that will be exposed to light to produce a metal particle forming reaction. By applying a laser, using a suitable mask or selecting a line exposure, various different platings can be successfully performed to perform an additive or semi-additive process to meet the needs of the electronics industry. These technologies are economically more economical and offer better application prospects. These technologies are relatively simple and can achieve high quality printed circuit boards. The printed circuit board has a fine pattern, a small gap, can achieve a large package density, and requires less process work. In addition, the polymer component containing TiO 2 as a main photocatalyst is applied to the unwinding process of the surface of the laminated board, so that a laminated board can be prepared, which can be completely dedicated to the industrial semi-additive and additive method to manufacture A printed circuit board.

An embodiment of a modification method of the laminate used in the manufacture of the printed circuit board will be described below.

Example 1

The laminate produced in accordance with the present invention comprises: a filler and a resin. This resin was used as a catalyst in an amount of 25% by weight based on the weight of the epoxy resin, and the surface of the laminate was spread to about 170% and had a drilled hole. The laminate is cut into pieces. This was cut into a sheet laminate activated with palladium salt and dried. After drying, the cut into sheet laminates were placed in a chemical copper bath for about 110 minutes. In this chemical copper bath, the entire surface of the cut sheet was covered with a copper layer of about 1.65 μm thick. This same copper layer is then overlaid on the inner surface of the drilled holes.

After the cut into a sheet laminate is activated according to the above method, the sheet is cut into a sheet and covered with a photoresist to have an image pattern. Then, the cut into a sheet laminate is immersed in In the copper trough, the printed circuit traces of the required size are simultaneously made and the holes are covered with copper.

Example 2

The surface of the sheet laminate was prepared by the method prepared in Example 1, and the dielectric surface and the inner surface of the drilled hole were activated by immersing the sheet into activating solution. The activation solution preferably comprises the following components: copper sulfate (CuSO ₄ * 5H ₂ O), which is used in an amount of 10% by weight; ethylenediaminetetraacetic acid (Trilon B), which is used in an amount of 22% by weight; Sodium hydroxide (NaOH), which is used in an amount of 10% by weight; α,α'-dipyridyl (α,α'-dipyridil), used in an amount of 10 mg/l; potassium ferricyanide (K ₃ ( Fe(CN) ₆ ), which was used in an amount of 30 mg/l; formalin, which was used in an amount of 10 mg/l; the solution temperature was about 65 ° C ± 5 ° C: and the pH of the solution was 12.5 to 13.0.

The laminated sheet cut into sheets was covered with a copper layer of about 1.50 μm thick, and the same copper layer was also overlaid on the inner surface of the drilled hole. The other processes of this printed circuit board are identical to the conventional removal process.

Example 3

On the laminated board prepared in Example 1, the printed circuit was applied by an additive method as described below.

Cutting the laminated board into a piece, and cutting the same into a hole in the laminated board; preparing the surface of the laminated board and drilling the hole; The cut into a sheet laminate is placed in a copper salt-based solution for activation; the surface of the cut sheet is cut to expose the inner surface of the pore to ultraviolet (UV) radiation; after activation, the mask is masked The coating is applied to a sheet laminate and exposed to radiation from an ultraviolet lamp; after exposure, a pattern formed of copper particles is produced by cutting the sheet onto the sheet. Then, the cut sheet is immersed in a chemical copper bath, and the required thickness of copper is coated on the laminate.

In the above embodiments, it was shown by testing that the dielectric was sufficiently usable, and the addition method and the semi-additive method were introduced and applied to the technical field.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the embodiments of the present invention, and the equivalents and modifications of the shapes, structures, materials, features, and spirits described in the claims of the present invention. All should be included in the scope of the patent application of the present invention.

Claims (7)

A method of modifying a laminate used in the manufacture of a printed circuit board, which is carried out using a subtractive method in which a tape made of a fibrous material is preferably filled with a thermosetting resin, using a curing agent and a An accelerator; then, the prepared material is subjected to a press molding process, which is carried out using a roller system; and the completed and cured laminate is cut into pieces, characterized in that in the laminated plate forming process, Adding a photocatalyst to a thermosetting epoxy resin of epoxy resin and/or acrylic acid and/or phenolic resin, the photocatalyst being used in an amount of 10% to 40% by weight based on the weight of the resin used, The photocatalyst is highly sensitive TiO ₂ , and its molecular formula is Me _n O _m (where n, m are natural numbers, Me is a metal, which is selected from one of Ti, Si, Zn, Bi, and W, here Me Ti, n = 1, m = 2); such a mixture is applied to the fibrous material; and then subjected to the press molding process; subsequently, the solidified laminated sheet is subjected to a surface development process of the laminated board At least 150.0% before its deployment; finally By using an additive method (additive process), or half-additive process (semi-additive process) is formed on the printed circuit laminates. The photocatalyst of the formula The method of modifying the application Laminates patentable scope of manufacturing printed circuit boards used, Paragraph 1, wherein the TiO ₂ added to the main (TiO ₂ -based) of the Me _n O _m (wherein, n, m is a natural number, Me is a metal, which is selected from one of Ti, Si, Zn, Bi, and W, where Me is Ti, n=1, m=2), and the amount thereof is compared The weight of the resin is from 15% to 20% by weight. A method of modifying a laminate used in the manufacture of a printed circuit board according to the first aspect of the invention, wherein the laminate surface development process is carried out using a chemical, physical, or physical/chemical method. A method for modifying a laminate used in the manufacture of a printed circuit board according to the first aspect of the invention, wherein the semi-additive method for forming the printed circuit means that the entire surface of the sheet having the drilled surface is cut into a laminated board Covered with copper, having a thickness of 1.5 μm to 2.0 μm, and covering copper on the inner surface of the drilled holes, the process of covering the laminated plate with copper is carried out by activating the laminated plate with palladium salt and Drying; then, immersing the laminate in a chemical copper bath and covering with copper, the immersion time is 60 minutes to 90 minutes; subsequently, the cut sheet is covered with a photoresist, which has imaging Pattern; then, the laminate is plated with chemical copper; and printed circuit traces are simultaneously made and the drilled holes are covered with copper. A method for modifying a laminate used in the manufacture of a printed circuit board according to claim 4, wherein the laminate is focused on a copper coating process by: immersing the laminate in the activation solution to dielectric surface of the laminate An activation process is performed with the inner surface of the borehole. The activation solution comprises the following components: copper sulfate (CuSO ₄ * 5H ₂ O), which is used in an amount of 10% to 12% by weight; and ethylenediaminetetraacetic acid (Trilon B), which is used in an amount of 20% to 25%. Percent by weight; sodium hydroxide (NaOH), used in an amount of 10% to 12% by weight; α,α'-dipyridyl (α,α'-dipyridil), used in an amount of 10 mg/l; iron Potassium cyanide (K ₃ (Fe(CN) ₆ ), used in an amount of 30 mg/l; formalin, used in an amount of 10 mg/l; solution temperature of about 65 ° C ± 5 ° C: and solution The pH was from 12.5 to 13.0; after drying the laminate, the laminate was entirely exposed to ultraviolet (UV) radiation. A method for modifying a laminate used in the manufacture of a printed circuit board according to the first aspect of the invention, wherein the use of the additive method to form the printed circuit means that the laminated plate having a drilled hole and cut into a sheet is Activation in a copper salt-based solution; Exposing the laminated sheet which is cut into pieces to perform an electroless plating process; by using a mask, exposing the surface of the laminated board and the inner surface of the drilled hole to ultraviolet (UV) radiation for about 15 to 20 seconds; The surface of the laminated board and the inner surface of the drilled hole are covered with a copper layer of a required thickness; after the activation process, the mask is coated on the laminated board to be exposed to ultraviolet light radiation; finally, by The laminate was immersed in the chemical copper solution bath, and the copper plate was patterned on the laminate and covered with copper. A method of modifying a laminate used in the manufacture of a printed circuit board according to claim 5 or 6, wherein the exposure process is carried out by selective exposure using laser light.