JP4430419B2 - Electronic circuit using parallel conductive circuit sheet and method for manufacturing the same - Google Patents

Description

  The present invention relates to a parallel conductive circuit sheet for connecting wirings of a double-sided / multi-layered printed circuit board used in any electronic device, or wiring of a printed circuit board and terminals of an electronic component, and particularly requires a highly accurate wiring mounting capability. The present invention relates to a parallel conductive circuit sheet capable of easily connecting fine wiring and an electronic circuit using the parallel conductive circuit sheet.

  With recent miniaturization and higher functionality of electronic devices, development of technology for mounting electronic components on a printed circuit board at high density has been underway. In particular, IC components can be mounted from surface mount types such as QFP and SOP, to wire bonding using gold wires between mounting terminals, or to flip chip mounting (FC mounting) where a semiconductor chip is directly mounted on a printed circuit board. The implementation method has changed.

  Here, FC mounting is a technique in which bumps are formed on the semiconductor chip side and the semiconductor chips are directly mounted on the printed circuit board via the bumps. There are three connection methods, such as solder connection, ACF connection, and gold / gold connection, for mounting on the printed circuit board. In particular, an anisotropic conductive film (ACF) is used for connection between printed circuit boards. ACF is an adhesive film in which a conductive filler of metal powder is kneaded into a thermosetting resin.

Here, the ACF connection method will be described with reference to FIG. First, as shown in FIG. 7A, a substrate 107 on which a wiring 109 is formed is prepared, and an ACF 103 is disposed on the upper surface of the substrate 107 and the wiring 109. Next, as shown in FIG. 7B, a semiconductor chip 111 is placed on the ACF 103, and a load is applied together with heat. Then, as shown in FIG.7 (c), the conductive filler 105 hardens | solidifies in the direction which crushes the conductive filler 105, and conduction | electrical_connection in the crushed direction is obtained. In addition, since the conductive filler 105 is not crushed between the adjacent terminals 113 of the semiconductor chip 111, insulation is maintained. In this state, the thermosetting resin is cured and the connection strength is secured.
“Monthly Semiconductor World”, September 1998, p157-158, “2. ACF Connection”

  By the way, the above-mentioned ACF has the advantage that the objects to be connected can be connected to each other at low temperature, the insulation between the terminals can be surely obtained, and the reliability of conduction is high. Due to the large size, there is a problem that adjacent wirings or IC terminals may be short-circuited.

  There are various sizes of the conductive filler 105, but the small size of the conductive filler 105 requires advanced techniques in the manufacturing technique, and is therefore expensive. When the size of the conductive filler 105 is selected at a price that can be used for a product, the filler size is limited to about φ = 5 nm. Therefore, when considering the insulation, the pitch between the printed circuit boards is naturally limited to 40 μm. It was. In order to solve the above problem, a method of reducing the mixing density of the conductive filler 105 is also conceivable. However, in this case, normal electrical connection may not be obtained. However, as described above, a narrow-width connection exceeding this limit pitch is desired from the current situation where high-density mounting of electronic devices is being promoted. On the other hand, there is a problem like this, but the current IC packaging technology always demands a finer and more accurate mounting capability. However, high-precision mounting of fine wiring has to rely on the skills of skilled workers. There is no problem.

  The present invention has been made in view of the above problems, and its object is to enable parallel wiring connection with a narrower width than in the prior art and a parallel conductive circuit sheet capable of easily performing fine and highly accurate mounting, and a parallel conductive circuit sheet. An object of the present invention is to provide an electronic circuit using a conductive circuit sheet.

In order to solve the above problems, an electronic circuit according to the present invention according to claim 1 includes a substrate having a plurality of conductive wirings formed at a predetermined interval, and a wiring direction of the conductive wirings provided on the substrate. An electronic component having a plurality of terminals formed at a predetermined interval facing the conductive wiring in the same direction, and a conductive circuit formed in parallel and on one surface of a sheet-like insulating layer A parallel conductive circuit sheet provided on the substrate for connecting and connecting the conductive wiring and the terminal, and the width and interval of the conductive circuit in the parallel conductive circuit sheet is the wiring of the conductive wiring The insulating layer on one end side in the longitudinal direction of the conductive circuit is removed, and the parallel conductive circuit sheet is disposed with the conductive circuit side facing the conductive wiring side of the substrate. Before One end side in the longitudinal direction of the parallel conductive circuit sheet in the conductive circuit is flip-chip mounted on the conductive circuit exposed by removing the insulating layer, and the parallel conductive circuit sheet in the conductive circuit The other end side in the longitudinal direction is characterized in that the conductive circuit and the conductive wiring are connected.

The present invention according to claim 2 is the electronic circuit according to claim 1, wherein the conductive wiring is formed such that an upper surface width is narrower than a lower surface width, and the other end side of the parallel conductive circuit sheet is the conductive wiring. The gist is that it is affixed to the upper surface and the side surface.

A third aspect of the present invention is the electronic circuit according to the first or second aspect, wherein the width of the conductive circuit is equal to or less than a half of a wiring interval of the conductive wiring in the substrate and a terminal of the electronic component. The gist is that it is 1/2 or less of the terminal interval.

The present invention according to claim 4 is a method of manufacturing an electronic circuit, comprising a substrate having a plurality of conductive wirings formed at a predetermined wiring interval and a plurality of terminals formed at a predetermined terminal interval. An electronic component and a plurality of conductive circuits formed in parallel on one surface of the sheet-like insulating layer, the width and interval of the conductive circuit being equal to or less than the wiring interval of the conductive wiring and the terminals of the electronic component; A parallel conductive circuit sheet having a terminal interval or less, wherein the insulating layer on one end side in the longitudinal direction of the conductive circuit is removed, and the conductive circuit side of the parallel conductive circuit sheet is connected to the conductive circuit side. The conductive wiring is disposed on the substrate toward the wiring side, and the other end side in the longitudinal direction of the conductive circuit of the parallel conductive circuit sheet is aligned with the wiring direction of the conductive wiring and the longitudinal direction of the conductive circuit. The electronic component is arranged in an overlapping manner on the conductive circuit exposed by removing the insulating layer, the terminal direction of the electronic component being aligned with the longitudinal direction of the conductive circuit, and the conductive wiring and the conductive circuit And the conductive circuit and the terminal are flip-chip mounted. The present invention according to claim 5 is the electronic circuit manufacturing method according to claim 4, wherein the conductive wiring is formed such that an upper surface width is narrower than a lower surface width, and the other end of the parallel conductive circuit sheet is connected to the other end of the parallel conductive circuit sheet. The gist is that the conductive wiring and the conductive circuit are connected to each other by being attached to an upper surface and a side surface of the conductive wiring.

  According to the present invention, a parallel conductive circuit sheet comprising a sheet-like insulating layer having a uniform thickness and a conductive circuit made of a conductive material formed on the surface of the insulating layer, A plurality of the conductive circuits are arranged in parallel, and at least the interval between the conductive circuits is set to be equal to or smaller than the wiring interval of the printed circuit board to be connected or the terminal interval of the IC component terminals. A plurality of conductive circuits are connected to the book. As a result, a narrow wiring connection can be achieved, and further, fine wiring connection and IC mounting, which have been required to have high-precision mounting capability, can be easily performed.

  Moreover, in this parallel conductive circuit sheet, the wiring width of the conductive circuit is set to 1/2 or less of the wiring interval of the printed circuit board or 1/2 or less of the terminal interval of the IC component, thereby enabling fine wiring connection and IC mounting. It becomes possible to carry out more easily.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a parallel conductive circuit sheet 1 according to an embodiment of the present invention. Here, FIG. 1A is a view of the parallel conductive circuit sheet 1 as viewed from above, and FIG. 1B is a cross-sectional view taken along line AA of the parallel conductive circuit sheet 1.

  As shown in FIGS. 1A and 1B, the parallel conductive circuit sheet 1 includes a sheet-like insulating layer 5 having a uniform thickness and a conductive material formed on the surface of the insulating layer 5. The conductive circuit 3 is composed of a plurality of conductive circuits 3 arranged in parallel. The width D of the conductive circuit 3 is at least the wiring interval da of the printed circuit board to be connected, or the terminal interval db of the IC component terminals, and is preferably 1/2 or less of the wiring interval da (or the terminal interval db). To do. More preferably, it is 1/3 or less. As a result, high-accuracy mounting can be more reliably performed, and furthermore, high-precision mounting work can be easily performed.

  Here, the conductive circuit 3 is preferably formed of gold, copper, tin, or the like, or has a configuration in which gold plating is performed after copper plating, or tin plating is performed after copper plating. . Thus, the wiring material cost can be suppressed by performing copper plating in advance. However, the present invention is not limited to this, and the conductive circuit 3 may be fabricated by 1 μm gold plating as necessary.

  On the other hand, the insulating layer 5 uses, for example, a thermosetting resin such as polyimide, or an epoxy or acrylic insulating resin material if used instead of an adhesive. Any one of these resin materials or a material in which any resin material is mixed may be applied. The insulating layer 5 is preferably processed into a sheet or film having a uniform thickness. The material of the insulating layer 5 is not limited to the above material, and any other material can be used as long as it is an insulating material.

  In addition, an additive method is used as a method for manufacturing the conductive circuit 3 formed on the insulating layer 5. By using the additive method, metal fine wiring can be easily produced. That is, by using the additive method, a narrow wiring having a width of 5 μm can be manufactured. This wiring manufacturing method can also be realized by using a subtractive method, but it is preferable to use the additive method from the viewpoint of work process and precision of microfabrication.

  Next, with reference to FIG. 2, FIG. 3, the production method and effect | action of the parallel conductive circuit sheet 1 which concern on embodiment of this invention are demonstrated.

  FIG. 2 is a diagram showing an arrangement configuration of the parallel conductive circuit sheet 1 before connection and the printed circuit board to be connected. FIG. 3A is a diagram showing an arrangement configuration of the parallel conductive circuit sheet 1 and the printed boards 7a and 7b after connection, and FIG. 3B is a top view of FIG. 3A.

  First, as shown in FIG. 2, printed circuit boards 7a and 7b to be connected are prepared, and the wiring directions of the conductive wirings 9 formed on the printed circuit boards 7a and 7b are made to coincide with each other, so that the printed circuit boards to be connected. The positions are adjusted so that the wirings 7a and 7b are aligned on the same line.

  Next, as shown in FIG. 3A, the parallel conductive circuit sheet 1 is lowered onto the printed circuit boards 7a and 7b, and after contacting the ends of the conductive wiring 9 and the conductive circuit 3 on the printed circuit boards 7a and 7b, The printed circuit boards 7a and 7b and the parallel conductive circuit sheet 1 are joined by applying a constant pressure from above the parallel conductive circuit sheet 1. By this joining, the two printed circuit boards 7a and 7b can be connected through the parallel conductive circuit sheet 1 so as to be conductive.

  Here, when the conductive circuit 3 is formed by gold plating and the conductive wiring 9 of the printed boards 7a and 7b to be connected is also formed by gold plating, they are bonded by ultrasonic diffusion bonding. On the other hand, when the conductive circuit 3 is formed by tin plating and the conductive wiring 9 of the printed circuit boards 7a and 7b to be connected is formed by gold plating, both wirings are joined by pressurization and heating (also called gold-tin bonding). ).

  Here, the width D of the conductive circuit 3 formed on the parallel conductive circuit sheet 1 is narrower than the width of the conductive wiring 9 of the printed circuit boards 7a and 7b, specifically 1/2 or less, preferably 1/3 or less. . Therefore, if the substrate surface (XY plane) of the parallel conductive circuit sheet 1 is aligned, the parallel conductive circuit sheet 1 can be joined in parallel on the printed circuit board only by alignment in the direction perpendicular to the substrate surface (θ direction). it can. As a result, since it can be mounted only with simple settings, it is possible to easily connect the fine wirings without the high-precision mounting capability as in the prior art.

  Further, as shown in FIG. 3B, since the width D of the conductive circuit 3 is sufficiently narrower than the wiring interval da of the conductive wiring 9 of the printed circuit boards 7a and 7b, a plurality of conductive circuits 3 are provided for one conductive wiring 9. Will be connected at the same time. Thereby, even if the wiring interval da is very narrow, the conductive circuit 3 of the parallel conductive circuit sheet 1 and the conductive wiring of the printed circuit board do not short-circuit because the wiring width D of the conductive circuit 3 is narrower.

  That is, conventionally, when the conductive wiring 9 is wide and the conductive wiring interval da is narrow, the conductive circuit 3 may be connected across the adjacent conductive wiring 9. For example, a plurality of conductive circuits 3 that are sufficiently narrower than the conductive wiring interval da are arranged in parallel, so that even if a slight misalignment occurs, the conductive circuit 3 and the conductive wiring 9 are not short-circuited, and high-precision wiring is achieved. Can be easily realized.

  Furthermore, as mentioned above, ACF is used for the connection between the conventional FPC (flexible substrate) and RPC (rigid substrate), and the wiring pitch is limited to about 40 μm due to the characteristics of the connection. However, by applying the parallel conductive circuit sheet 1 of the present invention, it becomes possible to connect the connection circuits with a pitch of 40 μm or less.

  In addition, since the parallel conductive circuit sheet 1 of the present invention has a simple parallel circuit structure, it is possible to manufacture a sheet by ordinary FPC. Moreover, when producing the parallel conductive circuit sheet 1 having a more precise pitch, the additive method is positively applied. By applying the additive method, high-precision wiring can be easily mass-produced when producing the same parallel circuit structure shown in this embodiment, and the cost performance is excellent. To do.

  The parallel conductive circuit sheet 1 according to the present invention can be easily used in the connection between wirings of the printed boards in which the conductive wiring 9 is formed with a narrow width and in the conductive connection between the printed board and the IC terminal. It becomes. With reference to FIGS. 4-6, the specific joining example using the parallel conductive circuit sheet 1 of this invention is demonstrated.

  First, referring to FIG. 4, the parallel conductive circuit sheet 1 of the present invention is used as an interposer (relay substrate for forming connection wiring between IC components and between semiconductor chips) in the FC mounting of the printed circuit board 7a and the IC components. An example will be described.

  4A and 4B are diagrams showing a connection configuration in which an IC component is mounted on a printed circuit board. FIG. 4A is a configuration diagram before connection, FIG. 4B is a configuration diagram after connection, and FIG. ) Shows a BB cross-sectional view of FIG.

  First, as shown to Fig.4 (a), the printed circuit board 7a which is a connection object, the parallel conductive circuit sheet 1, and IC are prepared. Here, the insulating layer 5 at one end of the parallel conductive circuit sheet 1 is removed by etching or the like so that a plurality of conductive circuits 3 are exposed. Placement adjustment is performed so that the surface direction of the parallel conductive circuit sheet 1 subjected to such processing is parallel to the surface direction of the printed circuit board 7a, and further, the wiring directions of the conductive circuit 3 and the conductive wiring 9 are matched. Adjust the XY plane direction.

  Next, as shown in FIG. 4B, after setting the conductive circuit 3 on the conductive wiring 9, alignment adjustment is performed so that the terminal of the IC component is arranged on the exposed conductive circuit 3, After this adjustment is completed, FC mounting is performed. As a specific connection method, when an object to be joined is an IC component as in this example, the IC terminal is made of gold or a solder bump and is connected by pressurization and heating.

  Next, another joining example will be described with reference to FIG. FIG. 5 shows an example of connection between printed circuit boards. The difference from the first embodiment (FIG. 2) is that the width of the conductive wiring formed on the printed circuit board 7c is wide and one conductive wiring 13a is wide. The other conductive wiring 13b is narrower than this.

  Even when the conductive wirings 13a and 13b have different widths as described above, when the conductive wirings 13a and 13b in which the narrow wiring width is accommodated in the wide wiring width direction are designed, the parallel conductive of the present invention is used. By using the circuit sheet 1, both conductive wirings 13a and 13b can be connected. Further, if the wiring spacing da of the conductive wirings 13a and 13b is the same, the conductive wirings 13a and 13b can be connected by using the parallel conductive circuit sheet 1 of the present invention.

  Next, still another joining example will be described with reference to FIG. 6A is an enlarged view of the end portion of the conductive wiring 9 formed on the printed circuit board, and FIG. 6B is a diagram illustrating a connection example of the conductive wiring 9 and the parallel conductive circuit sheet 1. .

  First, here, the conductive wiring 9 of the printed circuit board manufactured by a subtractive method such as a conventional FPC has a circuit upper surface width (top) narrower than a circuit lower surface width (bottom) as shown in FIG. That is, it has a trapezoidal cross section in which the circuit upper surface width is about 15-16 μm and the circuit lower surface width is 20 μm. However, since the IC component is mounted on the upper surface of the circuit, it is difficult to mount the IC component with high reliability unless the circuit upper surface width is secured to some extent. Therefore, if a wide circuit upper surface is formed, it is difficult to miniaturize the printed circuit board.

  However, the parallel conductive circuit sheet 1 of the present invention is produced by using the additive method, and as shown in FIG. 6 (b), it is attached by covering the circuit upper surface and the circuit side surface of the conductive wiring 9. A wide mounting effective width can be obtained on the extended line of the conductive circuit 3 formed.

  Therefore, by using the parallel conductive circuit sheet 1 of the present invention as an interposer, a sufficient mounting effective width can be obtained using the conventional narrow circuit upper surface. As a result, it is not necessary to mount in consideration of the circuit shape on the printed circuit board side.

It is a lineblock diagram of parallel conductive circuit sheet 1 concerning an embodiment of the invention, (a) is a top view of parallel conductive circuit sheet 1, and (b) is an AA sectional view of parallel conductive circuit sheet 1. It is arrangement | positioning block diagram of the parallel conductive circuit sheet 1 and printed circuit board 7a, 7b before a connection. FIG. 2 is an arrangement configuration diagram of the parallel conductive circuit sheet 1 and the printed boards 7a and 7b, in which (a) is an arrangement configuration diagram after connection, and (b) is a top view of (a). It is a block diagram of Example 1 which shows the example of joining using the parallel conductive circuit sheet 1 which concerns on embodiment of this invention. It is a block diagram of Example 2 which shows the example of joining using the parallel conductive circuit sheet 1 which concerns on embodiment of this invention. It is a block diagram of Example 3 which shows the example of joining using the parallel conductive circuit sheet 1 which concerns on embodiment of this invention. It is a figure which shows the connection structure of the conventional printed circuit board and IC components.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Parallel conductive circuit sheet 3 ... Conductive circuit 5 ... Insulating layer 7a, 7b ... Printed circuit board 9 ... Conductive wiring 13a, 13b ... Conductive wiring 103 ... ACF
105 ... Conductive filler 107 ... Substrate 109 ... Wiring 111 ... Semiconductor chip 113 ... Terminal

Claims (5)

A substrate having a plurality of conductive wirings formed at predetermined intervals;
An electronic component provided on the substrate and having a plurality of terminals formed at a predetermined interval facing the conductive wiring in the same direction as the wiring direction of the conductive wiring;
A parallel conductive circuit sheet provided on the substrate for connecting and connecting the conductive wiring and the terminal, the conductive circuit having a plurality of conductive circuits formed in parallel on one surface of the sheet-like insulating layer;
With
The width and interval of the conductive circuit in the parallel conductive circuit sheet are not more than the wiring interval of the conductive wiring and the terminal interval of the electronic component, and the insulating layer on one end side in the longitudinal direction of the conductive circuit is removed,
The parallel conductive circuit sheet is disposed with the conductive circuit side facing the conductive wiring side of the substrate,
One end side in the longitudinal direction of the conductive circuit of the parallel conductive circuit sheet is flip-chip mounted on the conductive circuit exposed by removing the insulating layer,
The electronic circuit, wherein the conductive circuit and the conductive wiring are connected to the other end side in the longitudinal direction of the parallel conductive circuit sheet in the conductive circuit. The electronic circuit according to claim 1,
The conductive wiring is formed such that the upper surface width is narrower than the lower surface width,
The other end side of the said parallel conductive circuit sheet is affixed on the upper surface and side surface of the said conductive wiring, The electronic circuit characterized by the above-mentioned. An electronic circuit according to claim 1 or 2,
The width of the said conductive circuit is 1/2 or less of the wiring space | interval of the conductive wiring in the said board | substrate, and 1/2 or less of the terminal space | interval of the terminal in the said electronic component, The electronic circuit characterized by the above-mentioned. An electronic circuit manufacturing method comprising:
A substrate having a plurality of conductive wirings formed at a predetermined wiring interval;
An electronic component having a plurality of terminals formed at predetermined terminal intervals;
A plurality of conductive circuits formed in parallel and on one surface of the sheet-like insulating layer, wherein the width and interval of the conductive circuit are less than or equal to the interval between the conductive wires and less than the interval between the terminals of the electronic component; Prepare a parallel conductive circuit sheet,
The parallel conductive circuit sheet is disposed on the substrate with an insulating layer on one end side in the longitudinal direction of the conductive circuit removed, and the parallel conductive circuit sheet is disposed on the substrate with the conductive circuit side of the parallel conductive circuit sheet facing the conductive wiring side. The other end side in the longitudinal direction of the conductive circuit of the sheet is arranged to overlap the conductive wiring so that the wiring direction of the conductive wiring and the longitudinal direction of the conductive circuit coincide with each other,
The electronic component is disposed on the conductive circuit exposed by removing the insulating layer so that the terminal direction of the electronic component coincides with the longitudinal direction of the conductive circuit,
A method of manufacturing an electronic circuit, wherein the conductive wiring and the conductive circuit are connected, and the conductive circuit and the terminal are flip-chip mounted. A method of manufacturing an electronic circuit according to claim 4,
The conductive wiring is formed such that the upper surface width is narrower than the lower surface width,
A method for manufacturing an electronic circuit, comprising: bonding the other end of the parallel conductive circuit sheet to an upper surface and a side surface of the conductive wiring to connect the conductive wiring and the conductive circuit.

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