JP4835892B2 - Method for forming small double-sided circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a small double-sided circuit, and more specifically, a first circuit is provided on one side of a substrate, and a second circuit is provided on the opposite side, both circuits being continuous via an IC circuit. The present invention relates to a method for forming a small double-sided circuit.
[0002]
[Prior art]
Conventionally, an RFID data carrier includes a coiled antenna circuit and an IC chip mounted on the antenna circuit. In that case, the circuit is formed by connecting the back end of the base material to the beginning and end of the line generally formed in a coil shape, and an IC chip mounting part is formed in the circuit to electrically connect the antenna circuit and the IC circuit. Thus, an RFID data carrier pattern is formed.
[0003]
In addition, when forming a coiled line on both sides of the substrate, the front and back coiled lines are connected in series, and the circuit is formed by electrically connecting the start and end of the line connected in series. An IC chip mounting portion is formed in the middle of the circuit, and the antenna circuit and the IC circuit are electrically connected to form an RFID data carrier pattern.
[0004]
In addition, the mounting of the IC chip is connected to the antenna circuit by a bare chip mounting, that is, a mounting technique for mounting a bare IC on a mounting substrate. Bare chip mounting connection techniques include a wire bonding method and a flip chip method. Resin sealing is performed to ensure reliability after connection.
[0005]
Bare chip mounting is used to reduce the size, thickness, and weight of electronic components. In addition, bare chip mounting allows higher density mounting than packaged products. The connection distance between the IC and the circuit board can be shortened, and it is possible to cope with higher speed systems. Therefore, it is applied in a wide range from general-purpose products such as calculators, watches, and portable devices to high-speed computers.
[0006]
However, the conventional flip chip is configured such that a protruding electrode (bump) is formed on the electrode pad of the IC chip and is mounted in alignment with the electrode pad on the opposite substrate. Is not provided with a means for electrically connecting two lines formed on the front and back of the base material.
[0007]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for forming a small double-sided circuit capable of simultaneously forming an antenna circuit by connecting front and back lines and connecting an IC circuit to the antenna circuit.
[0008]
[Means for Solving the Problems]
The invention according to claim 1 solves the above-described problem, and includes a first circuit on one side of the base material and a second circuit on the opposite side, both circuits being connected via an IC circuit. a method of forming a small double-sided circuit continuously has four bumps (a, B, b, b) comprises a single pair of which bumps (i, b) are electrically connected to each other, each of the remaining one pair of bumps (a, B) uses an IC chip connected to the terminal portion of its, at one of a pair of bumps connected to one terminal of the first circuit to the terminals of the IC chip ( connected to a), connects the other terminal to one (b) of a pair of bumps the electrically connected to each other, a pair of leads to one terminal of the second circuit to the terminals of the IC chip connected to one one remaining of the bump (B), were the other terminal connected the electrically to each other Characterized in that it connects to one one remaining of the pair of the bump (B).
[0009]
In the method of the present invention, a base material formed by laminating metal layers on both sides of a flexible substrate is prepared, a first circuit is formed on one surface by a photoetching method, and a second circuit is formed on the opposite surface. formed, a through hole leading to the terminal from the opposite side to the position corresponding to the both terminals of the first circuit is formed by any method of dry etching or wet etching, providing the second circuit side The IC chip is connected so that one of the bumps formed on the electrode pad of the IC chip is connected to the terminal of the first circuit through the through hole, and the other is connected to the terminal of the second circuit. combined and then mounted, connect the bumps to the respective terminals of the terminal and a second circuit of the first circuit, the other one end the end of the other one of the end end and a second circuit of the first circuit is the Electrically connected to each other By respectively connected to a pair of bumps it can be performed simultaneously by connecting the IC chip to connect the antenna circuit on the front and back of the line.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
[0011]
FIG. 1 shows a rear view of an IC chip 1 used in the method of the present invention. The IC chip 1 is four bumps (A, B, b, b) comprises a single pair of which bumps (i, b) is electrically connected via a wire 2 from each other, the rest a pair The bump (A, B) is connected to the terminal portion of the IC chip. It should be noted that the connection between A and B may be conducted by conduction in the IC circuit.
[0012]
FIG. 2 shows a state in which the antenna circuit is formed by connecting the front and back lines using the IC chip shown in FIG. 1 and the IC circuit is connected to the antenna circuit at the same time. IC chip 1 of bumps (A) is connected via a through hole 6 at one end the end 4a of the first circuit (Table circuits), bumps (B) is connected to a second end the end 5a of the circuit (back circuit) Has been. The other end end of the second circuit (not shown) is connected to the bump (B) which is not shown. On the other hand, the other end the end 4b of the first circuit is connected via a through hole 7 in the bump that is electrically connected to the bumps (A) and (B), the circuit as shown in FIG. 3 is formed.
[0013]
4 and 5 show examples of the first circuit and the second circuit. In the drawing, 8 indicates an area inside the antenna coil.
[0014]
As described above, according to the method of the present invention, an IC chip is mounted, and the antenna circuit is formed by connecting the front and back lines just by connecting, and the IC circuit is simultaneously connected to the antenna circuit. Can do.
[0015]
FIG. 6 shows a process of forming the first circuit and the second circuit on the front and back of the substrate.
A base material 22 in which a metal 21 such as a copper foil or an aluminum foil is laminated on both surfaces of a base material 3 made of an insulating plastic film such as PET or PI is prepared (FIG. 6A). Then, the both surfaces of the base material 22 to attach the resist pattern 23 (FIG. 6 (b)), to form a first circuit 4 and the second circuit 5 is peeled off registry after etching by wet etching (FIG. 6C). Finally, a through hole is formed 6,7 excimer laser, by impact carbon dioxide laser (FIG. 6 (d)).
[0016]
【The invention's effect】
As described above in detail, according to the method of the present invention, four bumps (A, B, b, b) comprises a single pair of which bumps (i, b) is electrically connected to each other cage, rest a pair of bumps (a, B) each uses the IC chip connected to the terminal portion of its one of the first of a pair of one of the terminal leads to the terminals of the IC chip of the circuit bumps one connect (a), a connected to one of a pair of bumps the electrically connected to each other and the other terminal (b). One of the terminal of the second circuit is connected to one one remaining of the pair of bumps connected to the terminals of the IC chip (B), a pair of bumps and the other terminal said electrically connected to each other of by connecting the remaining one one (B), it is possible to perform the forming of the antenna circuit by connecting the front and back of the line, to connect the IC chip to the antenna circuit at the same time.
[Brief description of the drawings]
FIG. 1 is a rear view of an IC chip used in a method of the present invention.
FIG. 2 is a schematic diagram showing a state in which an antenna circuit is formed by connecting front and back lines by the method of the present invention, and at the same time an IC chip is connected to the antenna circuit.
FIG. 3 is a circuit diagram of a circuit formed by the method of the present invention.
FIG. 4 is a plan view of a first circuit.
FIG. 5 is a plan view of a second circuit.
FIG. 6 shows a process of forming first and second circuits.
[Explanation of symbols]
1 IC chip A, B, Lee, b bump 2 wire 3 substrate 4a, 4b end end 5a of the first circuit, 5b second circuit end end 6, 7 through-hole 3 substrate 21 metal 22 matrix 23 , 24 Resist pattern 4 First circuit 5 Second circuit

Claims (3)

A method of forming a small double-sided circuit comprising a first circuit on one side of a substrate and a second circuit on the opposite side, both circuits being continuous via an IC circuit, a, B, Lee, comprising a b), one pair of which bumps (i, b) are electrically connected to each other, the rest a pair bumps (a, each of B) to the terminal portion of its using an IC chip lead, one of the terminals of the first circuit is connected to one one of a pair of bumps connected to the terminals of the IC chip (a), was the other terminal connected the electrically to each other connected to one one of the pair of bumps (b), connect one terminal of the second circuit to one one remaining of the pair of bumps connected to the terminals of the IC chip (B), the other to connect the remaining one one of the pair of bumps the electrically interconnected terminals (B) Method of forming a small double-sided circuit of symptoms. A base material formed by laminating metal layers on both sides of a flexible substrate is prepared, a first circuit is formed on one surface by a photoetching method, and a second circuit is formed on the opposite surface. A through hole reaching from the opposite surface side to the terminal at a position corresponding to both terminals of the circuit is formed by either dry etching or wet etching , and an IC chip is formed from the side where the second circuit is provided. one of bumps formed on the chip electrode pads is connected to a terminal of the first circuit via the through-hole and one mounted in alignment so as to be connected to the end edge of the second circuit , connecting the bumps to the respective terminals of the terminal and a second circuit of the first circuit, the other one end the end of the other one of the end end and a second circuit of the first circuit is connected the electrically to each other A pair of bumps each Method of forming a small double-sided circuit according to claim 1, characterized in that the connection.   3. The method for forming a small double-sided circuit according to claim 1, wherein the first and second circuits are antenna circuits connected in series.

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