TWI406610B - Method for manufacturing printed circuit board - Google Patents

Abstract

A method for manufacturing a printed circuit board includes the following steps. Firstly, a printed circuit substrate is provided. The printed circuit substrate includes an electrically conductive pattern layer and an insulative coverlayer adapted for protecting the electrically conductive pattern layer. The printed circuit substrate includes a main region and a connection region connected with the main region. The electrically conductive pattern layer in the main region includes at least two electrically conductive pads. The insulative coverlayer in the main region includes at least two through holes. The at least two through holes exposed at the at least two electrically conductive pads respectively. Secondly, an electrically conductive ink is deposited at surfaces of the insulative coverlayer, thus an ink structure is formed in the main region, and an ink testing structure electrically connected between the at least two electrically conductive pads is formed in the connection region. The ink testing structure includes a testing trace having a constant width. Finally, the printed circuit substrate is electrically tested, and the resistance of the testing trace is tested.

Description

Circuit board manufacturing method

The invention relates to a circuit board manufacturing technology, in particular to a method for manufacturing a circuit board capable of improving production efficiency.

With the advancement of science and technology, printed circuit boards have been widely used in the digital field. For application of the circuit board, please refer to the literature Takahashi, A.Ooki, N.Nagai, A.Akahoshi, H.Mukoh, A.Wajima,M.Res.Lab,High density multilayer printed circuit board for HITAC M-880,IEEE Trans .on Components, Packaging, and Manufacturing Technology, 1992, 15(4): 418-425. Moreover, digital products such as computers and mobile phones play an increasingly important role in people's daily life and automated production. The control and data registration of computers, mobile phones, etc. are mainly realized by buttons, and thus the importance of the button circuit board is unquestionable.

The surface of the button circuit board is almost filled by the button contacts, and there is often a phenomenon that contacts that need to be connected together cannot be connected by wiring on the conductive copper layer of the circuit board. In order to solve such problems, there is a jumper method in which an insulating layer is added to the conductive copper layer of the circuit board, the contact to be connected is exposed to the insulating layer, and a trace film layer is added to the insulating layer. To achieve the connection of the contacts. After the wiring film layer is formed, a protective layer for protection is usually formed thereon. The thickness of the trace film layer is directly related to the mechanical properties of the button contacts and the conduction performance between the button contacts. The sheet resistance Rsh is usually used to measure whether the thickness of the wiring layer is satisfactory. Therefore, after forming the trace film layer, it is necessary to test the sheet resistance value of the trace film layer. The sheet resistance Rsh is equal to the ratio of the resistivity to the film thickness, which is ρ/T. A conventional method for measuring the sheet resistance is performed by using a sheet resistance tester after forming a wiring film layer and forming a coating layer on the wiring film layer. In this way, it is necessary to purchase special instruments and add special test steps, which wastes a lot of manpower and material resources, which is not conducive to improving production efficiency.

In view of this, it is necessary to provide a method for manufacturing a circuit board to save cost and improve production efficiency.

A method of manufacturing a circuit board, comprising the steps of: providing a circuit substrate having a conductive pattern layer and an insulating protective layer for protecting the conductive pattern layer, wherein the circuit board substrate comprises a connected product area and an edge area The conductive pattern layer of the product area includes at least two conductive terminals, and the insulating protection layer of the product area has at least two through holes, and the at least two conductive terminals are respectively exposed to the at least two through holes; Conductive ink is disposed on the surface of the insulating protective layer to simultaneously form an ink structure in the product region and form an ink detecting structure on the surface of the insulating protective layer of the edge region, the ink structure electrically connecting the at least two conductive terminals The ink detecting structure includes a detecting wire having a constant width; and electrically detecting the conductive pattern layer of the product area, and checking The resistance value of the test wire is measured to determine whether the ink structure formed in the product area is qualified according to the resistance value of the test wire.

The manufacturing method of the circuit board provided by the technical solution forms an ink detecting structure including a detecting wire with a uniform width in the edge region while fabricating the ink structure in the product area. By judging whether the measured resistance value of the detected wire is within a certain range, it can be known whether the ink detecting structure is qualified, and further whether the ink structure of the product area is qualified. The manufacturing method of the circuit board using the technical solution does not require a special detecting instrument, and can be performed simultaneously with the electric measuring process of the circuit board, which is beneficial to saving cost and improving production efficiency.

10, 20‧‧‧ circuit substrate

101, 201‧‧‧Product Area

102, 202‧‧‧ marginal zone

11‧‧‧ basal layer

12‧‧‧ Conductive pattern layer

120‧‧‧Electrical terminals

121‧‧‧Wire

13, 23‧‧‧Insulation protective layer

130‧‧‧through hole

140, 240‧‧‧ ink structure

141, 241‧‧‧Ink detection structure

142‧‧‧Ink terminal

143‧‧‧Connecting line

144, 244‧‧‧ test terminals

145, 245‧‧‧ test leads

246‧‧‧First test wire segment

247‧‧‧Connected detection wire segments

248‧‧‧Second test wire segment

100‧‧‧Electric measuring machine

103‧‧‧Detection probe

104‧‧‧ Controller

FIG. 1 is a schematic structural view of a circuit substrate according to a first embodiment of the present technical solution.

2 is a schematic view showing the structure after applying conductive ink on the above circuit substrate.

Figure 3 is a partial cross-sectional view taken along line III-III of Figure 2.

FIG. 4 is a schematic structural view of electrical detection of the above circuit substrate.

FIG. 5 is a schematic structural view showing a conductive ink provided on a circuit substrate provided by a second embodiment of the present technical solution.

Figure 6 is a partial cross-sectional view taken along line VI-VI of Figure 5.

Figure 7 is a plan view of the ink detecting structure.

The circuit board provided by the technical solution will be described below with reference to the accompanying drawings and the plural embodiments. The production method will be further described in detail.

The first embodiment of the present invention provides a method for fabricating a circuit board, which includes the following steps: First, referring to FIG. 1, a circuit substrate 10 is provided. The circuit substrate 10 may be a rectangular parallelepiped plate including a connected product area 101 and an edge area 102. In this embodiment, the product area 101 is located in the middle of the circuit substrate 10 and has a rectangular cross-sectional shape. The edge area 102 is circumferentially connected around the product area 101 and has a ring shape.

The circuit substrate 10 is a single-sided copper-clad substrate including a base layer 11 , a conductive pattern layer 12 and an insulating protective layer 13 which are sequentially stacked. The base layer 11 may include only one insulating layer, and may include at least one wiring layer and at least one insulating layer alternately arranged. In the embodiment, the circuit substrate 10 is a single-sided copper-clad substrate, and the base layer 11 includes only one insulating layer.

The conductive pattern layer 12 of the product region 101 includes at least two conductive terminals 120 and at least one wire 121. In this embodiment, the conductive pattern layer 12 includes two conductive terminals 120 and three wires 121. The two conductive terminals 120 are spaced apart. The three wires 121 are disposed in parallel and are located between the two conductive terminals 120. Of course, for different types of circuit board products, the conductive pattern layer 12 may also be other structures accordingly. Of course, those skilled in the art can understand that the number of the conductive terminals 120 and the wires 121 is not limited, and the specific structure of the conductive pattern layer 12 is not limited. The conductive pattern layer 12 may further include other pads, edge joints, or other lines. FIG. 1 is only schematically showing the conductive pattern layer 12 Structure only.

The insulating protective layer 13 is used to protect the conductive pattern layer 12. The insulating protective layer 13 of the product region 101 covers the wires 121 of the conductive pattern layer 12 and fills the gaps of the conductive pattern layer 12, and exposes the conductive terminals 120. The insulating shielding layer 13 is provided with at least two through holes 130, the at least two through holes 130 are in one-to-one correspondence with the at least two conductive terminals 120, and the at least two conductive terminals 120 are respectively exposed to the at least two conductive terminals 120 In the two through holes 130.

In the second step, a conductive ink is disposed on the surface of the insulating protective layer 13 to form an ink structure 140 in the product region 101, and electrically connect the at least two conductive terminals on the surface of the insulating protective layer 13 of the edge region 102. The ink of 120 detects structure 141, resulting in a structure as shown in FIG.

The conductive ink may be a carbon ink, and the ink structure 140 and the ink detecting structure 141 may be formed on the insulating protective layer 13 by screen printing or coating. In this embodiment, the ink structure 140 and the ink detecting structure 141 are both formed on the surface of the insulating protective layer 13 by screen printing.

The ink structure 140 includes at least two ink terminals 142 and at least one connecting line 143. The at least two ink terminals 142 are in one-to-one correspondence with the at least two conductive terminals 120. The shape of the ink terminal 142 corresponds to the shape of the conductive terminal 120, and each ink terminal 142 is filled in a corresponding through hole 130 of the insulating protection layer 13. Each of the connection lines 143 is connected between the two ink terminals 142. Of course, corresponding to the structure of the conductive pattern layer 12, the ink structure 140 may be other for different types of circuit board products. structure. It will be understood by those skilled in the art that the number of the ink terminals 142 and the connection lines 143 is not limited, and the specific configuration of the ink structure 140 is not limited. FIG. 2 is only a schematic representation of the structure of the ink structure 140. In this embodiment, corresponding to the structure of the conductive pattern layer 12, the number of the ink terminals 142 is also two, and the number of the connection lines 143 is only one.

Referring to FIG. 2 and FIG. 3 together, the ink detecting structure 141 includes two detecting terminals 144 and one detecting wire 145. The width of the detecting wire 145 is constant. The two detecting terminals 144 are connected to both ends of the detecting wire 145. The length of the detecting wire 145 is L, the width is W, and the aspect ratio N is L/W. In this embodiment, each of the detecting terminals 144 has a rectangular parallelepiped shape, and the detecting wires 145 are elongated. When the ink detecting structure 141 is formed by printing, each of the detecting terminals 144 has a length of 1.2 mm and a width of 0.6 mm by designing the screen. The detecting wire 145 is connected between two adjacent long sides of the two detecting terminals 144. The detecting wire 145 has a length L of 20 mm, a width W of 0.4 mm, and an aspect ratio N of 50. In this embodiment, the line width of the detecting wire 145 is not equal to the line width of the connecting line 143 of the product area. Of course, the line width of the detecting wire 145 may also be equal to the line width of the connecting line 143.

Of course, after the ink structure 140 and the ink detecting structure 141 are formed, a protective layer covering the ink structure 140 may also be formed in the product region 101.

In the third step, referring to FIG. 4, the conductive pattern layer 12 of the product area 101 of the circuit substrate 10 is electrically detected, and the resistance value of the detecting wire 145 of the edge region 102 is detected, and is determined according to the resistance value of the detecting wire 145. Whether the ink structure 140 formed in the product area 101 is acceptable.

Specifically, the following steps can be taken: First, an electrical tester 100 is provided that includes two detection probes 103 and one controller 104. The two detecting probes 103 are in one-to-one correspondence with the two detecting terminals 144.

Of course, the electrical tester 100 can also include other detection probes for electrically detecting the product area 101 of the circuit substrate 10. The electrical measuring machine 100 detects the resistance between the two detecting terminals 144 and electrically detects the conductive pattern layer 12 of the product area 101 of the circuit substrate 10.

Next, the two detecting probes 103 are respectively brought into contact with the two detecting terminals 144, and the resistance value R of the detecting wire 145 is detected.

Finally, the controller 104 determines whether the ink structure 140 formed in the product area 101 is acceptable based on the resistance value of the detecting wire 145.

Assuming that the sheet resistance of the detecting wire 145 is R _sh and the value of the specified sheet resistance R _sh is greater than the minimum sheet resistance R _sh1 and less than the maximum sheet resistance R _sh2 , the formed detecting wire 145 meets the requirements. According to the law of resistance, the resistance R = ρ * L / (T * W) = L * R _sh / W. For the ink detecting structure 141 of the present embodiment, since the length of the detecting wire 145 is much larger than the width of the detecting terminal 144, the resistance of the detecting terminal 144 is ignored. The controller 104 analyzes the detection result. When the measured resistance value R is greater than L*R _sh1 /W and less than L*R _sh2 /W, it is determined that the sheet resistance R _{sh of the} ink detecting structure 141 is within a prescribed range. . In this embodiment, the aspect ratio N is 50, and the set minimum sheet resistance R _sh1 is 17 ohms per square, and the maximum square resistance R _sh2 is 20 ohms per square. That is, in the present embodiment, when the measured resistance value R is in the range of 850 ohms to 1000 ohms, the sheet resistance R _{sh of} the ink detecting structure 141 is within a predetermined range, thereby indicating that the thickness of the ink detecting structure 141 is judged to be acceptable. Since the ink detecting structure 141 is formed in the same step as the ink structure 140 of the product region 101, the ink structure 140 located in the product region 101 is also qualified.

The manufacturing method of the circuit board provided by the first embodiment of the present invention forms the ink structure 140 in the product area 101 while forming the ink detecting structure 141 including the detecting wire 145 having a constant width in the edge region 102. It is only necessary to judge whether the measured resistance value R of the detecting wire 145 is within a certain range, and it is known whether the ink detecting structure 141 is qualified, and further whether the ink structure 140 of the product area is qualified. The method for manufacturing the circuit board provided by the first embodiment of the technical solution does not require a special detecting instrument, and can be performed simultaneously with the electrical testing process of the circuit board, which is beneficial to saving cost and improving production efficiency.

Referring to FIG. 5 to FIG. 7 , the method for fabricating the circuit board provided by the second embodiment of the present invention is substantially the same as that of the first embodiment, and includes the following steps: First, providing a product area 201 and surrounding The circuit substrate 20 of the edge region 202 of the product area 201.

In the second step, a conductive ink is disposed on the surface of the insulating protective layer 23 to form an ink structure 240 in the product region 201, and an ink detecting structure 241 is formed on the surface of the insulating protective layer 23 of the edge region 202, as shown in FIG. The structure.

Different from the first embodiment, in the ink detecting structure 241, the detecting wire 245 is a broken line, which includes a first detecting wire segment 246, a connecting detecting wire segment 247 and a second detecting wire segment 248 which are sequentially connected. . One detection terminal 244 is connected to the first detection lead segment 246 and the other detection terminal 244 is connected to the second detection lead segment 248. The connection detecting wire segment 247 has an angle with the first detecting wire segment 246. The second detecting wire segment 248 also has an angle with the connection detecting wire segment 247. In this embodiment, the second detecting wire segment 248 is parallel to the first detecting wire segment 246, and the connecting detecting wire segment 247 is vertically connected between the second detecting wire segment 248 and the first detecting wire segment 246. The first detecting wire segment 246 and the second detecting wire segment 248 are both connected to the same side of the connecting detecting wire segment 247. That is, the angle between the connection detecting wire segment 247 and the first detecting wire segment 246 is 90 degrees. The angle between the second detecting wire segment 248 and the connection detecting wire segment 247 is also 90 degrees. In this embodiment, the widths of the first detecting wire segment 246, the connecting detecting wire segment 247 and the second detecting wire segment 248 are both 0.4 mm. The length L ₁ of the first detecting wire segment 246 is 8 mm, the length L _C of the connection detecting wire segment 247 is 4 mm, and the length L ₂ of the second detecting wire segment 248 is 8 mm. The total length L _T = L ₁ + L _C + L _{2 of} the test lead 245, that is, also 20 mm, the width W is 0.4 mm, and the aspect ratio N is still 50.

In the third step, the circuit substrate 20 is electrically detected to detect the resistance value of the ink detecting structure 241 of the edge region 202, and the controller 104 determines the ink structure formed in the product region 201 according to the detection result of the ink detecting structure 241. 240 is qualified.

When the value of the specified sheet resistance R _sh is greater than the minimum sheet resistance R _sh1 and less than the maximum sheet resistance Rsh2 , the formed detecting wire 245 meets the requirements. According to the law of resistance, the resistance R-ρ *L _T /(T*W)=(L ₁ +L _C +L ₂ )*R _sh /W. When the measured resistance value R is greater than (L ₁ + L _C + L ₂ ) * R _sh1 /W and less than (L ₁ + L _C + L ₂ ) * R _sh2 / W, it represents the ink detecting structure 241 The sheet resistance R _{sh is} acceptable. Although the structure of the detecting wire 245 in this embodiment is different from the detecting wire 145 of the first embodiment, since the aspect ratio N of the detecting wire 245 is still 50, the controller 104 analyzes the detection result. When the measured resistance value R is in the range of 850 ohms to 1000 ohms, it is judged that the sheet resistance R _{sh of the} ink detecting structure 241 is acceptable, thereby indicating that the thickness of the ink detecting structure 241 is acceptable.

The manufacturing method of the circuit board provided by the second embodiment of the present invention forms the ink detecting structure 241 in the edge region 202 while the ink structure 240 is formed in the product area 201. The detecting wire 245 of the embodiment is a fold line, which is advantageous for improving the space utilization rate of the edge region 202.

It can be understood that the aspect ratio N of the detecting wire is not limited to 50, and the shape of the detecting wire is not limited to a structure such as a straight line or a broken line, and may be other structures such as a curve and a zigzag shape, which may be according to a circuit substrate. The shape of the space that can be utilized in the edge area is correspondingly designed, and only the width W of each part is required to be equal.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

10‧‧‧ circuit board

101‧‧‧Product Area

102‧‧‧Edge area

13‧‧‧Insulation protection layer

130‧‧‧through hole

140‧‧‧Ink structure

141‧‧‧Ink detection structure

142‧‧‧Ink terminal

143‧‧‧Connecting line

144‧‧‧Detection terminal

145‧‧‧Test wire

Claims (10)

A method of manufacturing a circuit board, comprising the steps of: providing a circuit substrate having a conductive pattern layer and an insulating protective layer for protecting the conductive pattern layer, wherein the circuit board substrate comprises a connected product area and an edge area The conductive pattern layer of the product area includes at least two conductive terminals, and the insulating protection layer of the product area has at least two through holes, and the at least two conductive terminals are respectively exposed to the at least two through holes; Conductive ink is disposed on the surface of the insulating protective layer to simultaneously form an ink structure in the product region and form an ink detecting structure on the surface of the insulating protective layer of the edge region, the ink structure electrically connecting the at least two conductive terminals The ink detecting structure includes a detecting wire having a constant width; and electrically detecting the conductive pattern layer of the product area, and detecting the resistance value of the detecting wire to determine whether the ink structure formed in the product area is determined according to the resistance value of the detecting wire qualified. The method for fabricating a circuit board according to claim 1, wherein the ink structure and the ink detecting structure are formed on the circuit substrate by screen printing or coating. The manufacturing method of the circuit board of claim 1, wherein the ink structure comprises at least two ink terminals and at least one connecting line, and the at least two ink terminals are respectively located in the at least two through holes And respectively connected to the at least two conductive terminals, the at least one connecting line is formed on a surface of the insulating protective layer and is connected between the at least two ink terminals. The method of manufacturing a circuit board according to the first aspect of the invention, wherein the detecting wire is a straight line. The method for manufacturing a circuit board according to claim 4, wherein when the resistance value of the detecting wire is greater than L*R _sh1 /W and less than L*R _sh2 /W, the determination is formed in the product area. The ink structure is qualified, wherein R _sh1 is the minimum sheet resistance, R _sh2 is the maximum sheet resistance, W is the width of the detecting wire, and L is the length of the detecting wire. The method of manufacturing the circuit board of claim 1, wherein the detecting wire comprises a first detecting wire segment connected in series, a connecting detecting wire segment and a second detecting wire segment, wherein the first detecting wire segment The connection detecting wire segment is equal in width to the second detecting wire segment, the connection detecting wire segment has an angle between the first detecting wire segment, and the second detecting wire segment and the connecting detecting wire segment are also Angle. The method for manufacturing a circuit board according to claim 6, wherein the first detecting wire segment and the second detecting wire segment are both connected to a same side of the connecting detecting wire segment, and the connecting detecting wire segment and the first An angle between the detecting wire segments is 90 degrees, and an angle between the second detecting wire segment and the connecting detecting wire segment is also 90 degrees. The method for manufacturing a circuit board according to claim 6, wherein when the resistance value of the detecting wire is greater than (L ₁ + L _C + L ₂ ) * R _sh1 / W, and less than (L ₁ + L) _{When C} + L ₂ )*R _sh2 /W, it is determined that the ink structure formed in the product area is qualified, wherein R _sh1 is the minimum sheet resistance, R _sh2 is the maximum sheet resistance, W is the width of the detecting wire, and L ₁ is The length of the first detecting wire segment, L _C is the length of the connecting detecting wire segment, and L ₂ is the length of the second detecting wire segment. The method for manufacturing a circuit board according to the first aspect of the invention, wherein the ink detecting structure comprises two detecting terminals respectively connected to two ends of the detecting wire, and electrically detecting the circuit substrate, The method includes the following steps: providing an electric measuring machine, comprising two detecting probes and a controller, wherein the two detecting probes are in one-to-one correspondence with the two detecting terminals; respectively, respectively, two detecting probes and the two detecting The terminal corresponds to the contact, and detects a resistance value of the detection wire; and the controller determines whether the ink structure formed in the product area is qualified according to the detection result. The method for fabricating a circuit board according to claim 1, wherein after forming the ink structure and the ink detecting structure, forming the covering ink in the product area before performing electrical detection on the circuit substrate The protective layer of the structure.