1. Technical Field
The present disclosure generally relates to printed circuit boards (PCBs), and particularly to printed circuit board having gold fingers and a method for manufacturing the printed circuit board.
2. Description of Related Art
To accommodate development of miniaturized electronic products with multiple functions, printed circuit boards are widely used due to their special characteristics such as lightness and high-density interconnect-ability.
A typical printed circuit board is assembled to another printed circuit board or an electronic element via gold fingers under a process of hot pressure welding. In the process of the hot pressure welding, identification marks relating to gold fingers are needed to be formed on the printed circuit board, such that a welding machine can confirm the positions of the gold finger by identifying the positions of the identification marks, and then welds the printed circuit board to another printed circuit board or the electronic element. Therefore, position deviation between the gold fingers and the identification marks is limited to a smaller level, and a method for manufacturing the identification marks must have high precision. If the position deviation between the gold fingers and the identification marks is larger, the gold fingers of the printed circuit board cannot be well assembled to another printed circuit board or the electronic element in the hot pressure welding process.
What is needed, therefore, is a printed circuit board and a method for manufacturing the printed circuit board to overcome the above-described problems.
Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, all the views are schematic, and like reference numerals designate corresponding parts throughout the several views.
A printed circuit board and a method for manufacturing the printed circuit board according to embodiments will be described with reference to the drawings.
A method of manufacturing a printed circuit board according to an exemplary embodiment includes the steps as follows.
In the present embodiment, the first circuit substrate 110 includes a first insulation layer 111, a first inner electrically conductive pattern layer 112, and a first copper foil 113. The first inner electrically conductive pattern layer 112 and the first copper foil 113 are formed at the opposite surfaces of the first insulation layer 111.
The shape and size of the second circuit substrate 120 are identical to the shape and size of the first circuit substrate 110. The second circuit substrate 120 includes a second insulation layer 121, a second inner electrically conductive pattern layer 122, and a second copper foil 123. The second inner electrically conductive pattern layer 122 and the second copper foil 123 are formed on the opposite surfaces of the second insulation layer 121. The second circuit substrate 120 includes at least one marking region 124. There is no the second electrically conductive pattern layer 122 in the marking region 124. That is, the marking region 124 consists of the second insulation layer 121 and the second copper foil 123. In the present embodiment, there are two marking regions 124 separated from each other. Each of the marking regions 124 is in the shape of a square, and the side length of the marking regions 124 is in a range from 0.8 millimeters to 1.0 millimeters. In other embodiments, the marking region 124 may be a round marking region, or a triangle marking region, or a hexagonal making region, for example.
In the present embodiment, the first outer electrically conductive pattern layer 115, the second outer electrically conductive pattern layer 125, and the at least one identification mark 126 are simultaneously formed by an image-transfer process and a etching process.
The first outer electrically conductive pattern layer 115 includes a plurality of first electrically conductive traces 1151, and a plurality of first gold fingers 1152. The first gold fingers 1152 spatially correspond the first electrically conductive traces 1151, and the first gold fingers 1152 are respectively in contact with and electrically connected to the first electrically conductive traces 1151. In the present embodiment, the first gold fingers 1152 are positioned between the two through holes 101.
The second outer electrically conductive pattern layer 125 includes a plurality of second electrically conductive traces 1251, and a plurality of second gold fingers 1252. The second gold fingers 1252 spatially correspond the second electrically conductive traces 1251, and the second gold fingers 1252 are respectively in contact with and electrically connected to the second electrically conductive traces 1251. The second copper foil 123 in the marking region 124 is etched to be an identification mark 126. In the present embodiment, the identification mark 126 is also in the shape of a square, and the side length of the identification mark 126 is in a range from 0.5 millimeters to 0.8. That is, the shape of the identification mark 126 is the same as the shape of the marking region 124, and the size of the identification mark 126 is smaller than the size of the marking region 124.
In alternative embodiments, the method for manufacturing the printed circuit board 100 may be used for manufacturing another multi-layered printed circuit board, which has more electrically conductive pattern layer than the printed circuit board 100. That is, when the first circuit substrate 110 is laminated onto the second circuit substrate 120, there may be one or more third circuit substrates between the first circuit substrate 110 and the second circuit substrate 120, and there may be another connection adhesive sheet between two adjacent third circuit substrates. Each third circuit substrate may includes a third insulation layer and at least one third inner electrically conductive pattern layer formed at a side of the third insulation layer, and at least one second through hole is defined in the third circuit substrate. The at least one second through hole corresponds to the at least one marking region 124. After lamination, step 5 to step 6 can successively be processed to form another multi-layered printed circuit board having more electrically conductive pattern layer than the printed circuit board 100.
In further alternative embodiments, the step of forming the inner cover layer 140 on the side of the second inner electrically conductive pattern layer 120 of the second circuit substrate 120 may be omitted, in such case, there is only the connection adhesive sheet 130 between the first inner electrically conductive pattern layer 112 and the second inner electrically conductive pattern layer 122.
The printed circuit board 100 manufactured by the above method includes the first outer electrically conductive pattern layer 115, the first insulation layer 111, the first inner electrically conductive pattern layer 112, the connection adhesive sheet 130, the inner cover layer 140, the second inner electrically conductive layer 122, the second insulation layer 121, the second outer electrically conductive pattern layer 125, and at least one identification mark 126, which are arranged in that order. At least one blind hole 102 is formed in the printed circuit board 100. The blind hole 102 only passes through the first outer electrically conductive pattern layer 115 and the connection adhesive sheet 130. The first outer electrically conductive pattern layer 115 includes the first electrically conductive traces 1151 and the first gold fingers 1152. The second outer electrically conductive pattern layer 125 includes the second electrically conductive trace 1251 and the second gold fingers 1252. The at least one identification mark 126 corresponds to the at least one blind hole 102. The identification mark 126 is formed on the second insulation layer 121. The first outer electrically conductive pattern layer 115, the second outer electrically conductive pattern layer 125, and the identification mark 126 are simultaneously formed. The second insulation layer 121 and the inner cover layer 140 are made of a transparent material, for example, Polyimide, or Polyester, for example.
The printed circuit board 100 also includes the first outer cover layer 150 and the second outer cover layer 160. The first outer cover layer 150 is formed at a side of the first outer electrically conductive pattern layer 115, and the second outer cover layer 160 is formed at a side of the second outer electrically conductive pattern layer 125. The first openings 151 and the second opening 152 are defined in the first outer cover layer 150. The first openings 151 spatially correspond to the first gold fingers 1152, and the first gold finger 1152 are respectively exposed through the first openings 151. The second openings 152 spatially correspond to the through holes 101, and the second openings 152 respectively communicates with the through holes 101. The third openings 161 and the fourth openings 162 are defined in the second outer cover layer 160. The third openings 161 spatially correspond to the second gold fingers 1252, and the second gold fingers 1252 are respectively exposed through the third openings 161. The fourth openings 162 spatially correspond to the identification marks 126, and the size of each fourth opening 162 is larger than the size of the corresponding identification mark 126. The size of each fourth opening 162 is identical to the size of the corresponding marking region 124.
In other embodiments, the printed circuit board 100 may have more electrically conductive pattern layer. That is, there may be more inner electrically conductive pattern layers and insulation layers alternatively formed between the connection adhesive sheet 130 and the inner cover layer 140. The blind hole 102 passes through the inner electrically conductive pattern layers and insulation layers alternatively formed.
In the present embodiment, the second insulation layer 121 and the inner cover layer 140 are made of a transparent material, for example, Polyimide, or Polyester, for example. In the hot pressure welding process, it is very easy for the welding machine to identify the identification mark 126.
Because the identification mark 126, the first gold fingers 1152, and the second gold fingers 1252 are formed simultaneously, the position deviation between the identification mark 126, the first gold finger 1152, and the second gold finger 1252 is smaller, and making precision of the identification mark 126 is higher.
While certain embodiments have been described and exemplified above, various other embodiments will be apparent from the foregoing disclosure to those skilled in the art. The disclosure is not limited to the particular embodiments described and exemplified but is capable of considerable variation and modification without departure from the scope and spirit of the appended claims.
Number | Date | Country | Kind |
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2012104092978 | Oct 2012 | CN | national |