JP3561683B2 - Circuit device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a support board is not substantially needed and is an excessive material and the thickness of the support board large-sizes a circuit device mounting a circuit element as a printed board, a ceramic board, a flexible sheet and the like are made the support boards. SOLUTION: After a first trench 61 is formed on a first conductive foil 60A and a second trench 62 is formed on a second conductive foil 60B, the circuit element is mounted to fix an insulation resin 50 as the integrated conductive foil 60 is made the support board, after it is inverted, and at this time the connection part 64 of the second conductive foil 60B is etched as the insulation resin 50 is made the support board so as to be separated as a conductive path. Thus, the conductive path 51 and the circuit element 52 can realize the circuit device supported on the insulation resin 50 without employing the support board. Furthermore, pieces of wiring L1-L3 needed absolutely for the circuit exist, and slipping can be prevented because it has curved structures 59, 63 and a visor 58.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a circuit device, and more particularly to a method for manufacturing a thin circuit device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a circuit device set in an electronic device is used for a mobile phone, a portable computer, and the like, and therefore, a reduction in size, thickness, and weight is required.
[0003]
For example, taking a semiconductor device as an example of a circuit device, a general semiconductor device is a packaged semiconductor device sealed with a conventional transfer mold. This semiconductor device 1 is mounted on a printed circuit board PS as shown in FIG.
[0004]
In the package type semiconductor device 1, a semiconductor chip 2 is covered with a resin layer 3 and a lead terminal 4 for external connection is led out from a side of the resin layer 3.
[0005]
However, in this package type semiconductor device 1, the lead terminals 4 are protruded from the resin layer 3, so that the overall size is large, and the size, thickness, and weight are not satisfied.
[0006]
For this reason, companies have competed to develop various structures in order to realize miniaturization, thinning and weight reduction, and recently called a CSP (chip size package), a wafer scale CSP equivalent to the chip size, or chip size A CSP with a size slightly larger than that has been developed.
[0007]
FIG. 27 shows a CSP 6 that employs a glass epoxy substrate 5 as a support substrate and is slightly larger than the chip size. Here, description will be made assuming that the transistor chip T is mounted on the glass epoxy substrate 5.
[0008]
A first electrode 7, a second electrode 8, and a die pad 9 are formed on the front surface of the glass epoxy substrate 5, and a first back electrode 10 and a second back electrode 11 are formed on the back surface. The first electrode 7 and the first back electrode 10 are electrically connected to each other, and the second electrode 8 and the second back electrode 11 are electrically connected to each other through the through hole TH. The bare transistor chip T is fixed to the die pad 9, the emitter electrode of the transistor is connected to the first electrode 7 via a thin metal wire 12, and the base electrode of the transistor and the second electrode 8 are connected to the thin metal wire 12. Connected through. Further, a resin layer 13 is provided on the glass epoxy substrate 5 so as to cover the transistor chip T.
[0009]
Although the CSP 6 employs the glass epoxy substrate 5, unlike the wafer scale CSP, the extending structure from the chip T to the back surface electrodes 10 and 11 for external connection is simple and has an advantage that it can be manufactured at low cost.
[0010]
The CSP 6 is mounted on a printed circuit board PS as shown in FIG. The printed circuit board PS is provided with electrodes and wiring constituting an electric circuit, and the CSP 6, the package type semiconductor device 1, the chip resistor CR or the chip capacitor CC and the like are electrically connected and fixed.
[0011]
The circuit formed by the printed circuit board is mounted in various sets.
[0012]
Next, a method of manufacturing the CSP will be described with reference to FIGS. In FIG. 30, a flowchart entitled "Galaepoe / flexible substrate in the center" is referred to.
[0013]
First, a glass epoxy substrate 5 is prepared as a base material (support substrate), and Cu foils 20 and 21 are pressure-bonded to both surfaces thereof via an insulating adhesive. (See FIG. 29A above)
Subsequently, Cu foils 20 and 21 corresponding to the first electrode 7, the second electrode 8, the die pad 9, the first back surface electrode 10 and the second back surface electrode 11 are coated with an etching-resistant resist 22, The foils 20 and 21 are patterned. The patterning may be performed separately on the front and back sides. (See FIG. 29B above)
Subsequently, a hole for the through hole TH is formed in the glass epoxy substrate by using a drill or a laser, and the hole is plated to form the through hole TH. The first electrode 7 and the first back electrode 10 and the second electrode 8 and the second back electrode 10 are electrically connected by the through hole TH. (See FIG. 29C above)
Although not shown in the drawings, the first electrode 7 and the second electrode 8 serving as bonding posts are plated with Ni, and the die pads 9 serving as die bonding posts are plated with Au, and the transistor chip T is die-bonded. I do.
[0014]
Finally, the emitter electrode of the transistor chip T and the first electrode 7, and the base electrode of the transistor chip T and the second electrode 8 are connected via a thin metal wire 12 and covered with a resin layer 13. (See FIG. 29D above)
Then, if necessary, the wafer is diced and separated as individual electric elements. In FIG. 28, only one transistor chip T is provided on the glass epoxy substrate 5, but in reality, many transistor chips T are provided in a matrix. Therefore, they are finally separated by a dicing device.
[0015]
By the above manufacturing method, a CSP type electric element using the support substrate 5 is completed. This manufacturing method is the same even when a flexible sheet is used as the support substrate.
[0016]
On the other hand, a manufacturing method using a ceramic substrate is shown in the flow on the left side of FIG. After a ceramic substrate as a support substrate is prepared, through holes are formed, and thereafter, front and rear electrodes are printed and sintered using a conductive paste. After that, until the resin layer of the previous manufacturing method is covered, the manufacturing method is the same as that of FIG. 29. However, the ceramic substrate is very fragile, and unlike a flexible sheet or a glass epoxy substrate, it is chipped immediately, so a mold is used. There is a problem that can not be molded. Therefore, after potting and hardening the sealing resin, polishing for flattening the sealing resin is performed, and finally, individual separation is performed using a dicing apparatus.
[0017]
[Problems to be solved by the invention]
In FIG. 28, the transistor chip T, the connection means 7 to 12 and the resin layer 13 are necessary components for electrical connection to the outside and protection of the transistor. It has been difficult to provide an electric circuit device that realizes reduction in thickness, thickness, and weight.
[0018]
Further, the glass epoxy substrate 5 serving as a support substrate is not necessary as described above. However, due to the manufacturing method, the glass epoxy substrate 5 was employed as a support substrate for bonding the electrodes, and the glass epoxy substrate 5 could not be eliminated.
[0019]
For this reason, adoption of the glass epoxy substrate 5 increases the cost, and further, because the glass epoxy substrate 5 is thick, the circuit device becomes thick, and there is a limit to the reduction in size, thickness, and weight.
[0020]
Further, a through-hole forming step for connecting electrodes on both surfaces is indispensable for a glass epoxy substrate or a ceramic substrate, and there is a problem that the manufacturing process becomes long.
[0021]
FIG. 31 shows a pattern diagram formed on a glass epoxy substrate, a ceramic substrate, a metal substrate, or the like. In this pattern, an IC circuit is generally formed, and a transistor chip 21, an IC chip 22, a chip capacitor 23, and / or a chip resistor 24 are mounted. A bonding pad 26 integrated with the wiring 25 is formed around the transistor chip 21 and the IC chip 22, and the chips 21 and 22 are electrically connected to the bonding pads via thin metal wires 28. The wiring 29 is formed integrally with the external lead pad 30. These wirings 25 and 29 extend while bending in the substrate, and are formed as thinnest as necessary in the IC chip. Accordingly, the thin wiring has a very small area of adhesion to the substrate, and has a problem that the wiring is peeled off or warped. The bonding pad 26 includes a power bonding pad and a small signal bonding pad. Particularly, the small signal bonding pad has a small bonding area and causes film peeling.
[0022]
Further, the external lead is fixed to the external lead pad, but there is a problem that the external lead pad is peeled off by an external force applied to the external lead.
[0023]
[Means for Solving the Problems]
The present invention has been made in view of the above-mentioned many problems, and has a step of preparing a laminated conductive foil in which a first conductive foil and a second conductive foil are laminated, and the step of removing at least a region serving as a conductive path. Forming a first separation groove in the first conductive foil to form a first conductive path having a curved side surface; and forming a portion corresponding to the first separation groove in the second conductive foil in a thickness direction. Forming a second separation groove by partially removing the connection portion to leave a connection portion, and simultaneously forming a second conductive path on the back surface of the first conductive path; Electrically connecting and fixing on the first conductive path; and covering the circuit element and the first conductive path with an insulating resin so as to fill the first and second separation grooves. Molding, and removing the connection portion of the second conductive foil.
[0024]
In the present invention, the second conductive foil is used as an etching stopper when forming the first conductive path, and the first conductive path is prevented from being separated separately. And finally, it is used as a second conductive path. Further, the conductive path is integrally supported by the insulating resin filled in the first and second separation grooves, thereby preventing the conductive path from coming off. Of course, through holes can be eliminated.
[0025]
Further, the present invention provides a step of preparing a laminated conductive foil in which a first conductive foil and a second conductive foil are laminated, and forming a corrosion-resistant conductive film on at least a region serving as a conductive path on the surface of the first conductive foil. Forming a first separation groove in the first conductive foil excluding at least a region serving as a conductive path to form a first conductive path having a curved side surface; A part of the second conductive foil corresponding to the groove is partially removed to form a second separation groove while leaving a connection part, and at the same time, a second conductive path is formed on the back surface of the first conductive path. Electrically connecting and fixing a desired circuit element on a desired first conductive path, and electrically connecting an electrode of the circuit element to the desired first conductive path. Forming a connection means, covering the circuit element, the connection means and the first conductive path, Molding with an insulating resin so as to fill the first and second separation grooves, and fitting the first and second conductive paths to the insulating resin; and connecting the second conductive foil to the first and second conductive paths. Removing the part.
[0026]
Further, in the present invention, the second conductive foil is used as an etching stopper when forming the first conductive path, and the first conductive path is prevented from being separated separately. And finally, it is used as a second conductive path. In addition, an eave is formed on the surface of the conductive path by adopting the conductive film, and the conductive path is prevented from coming off by the insulating resin that covers the eave and is filled in the first and second separation grooves. . Of course, through holes can be eliminated.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
First embodiment of the present invention
A first embodiment of a method for manufacturing a circuit device 53 according to the present invention will be described with reference to FIGS.
[0028]
The present invention provides a step of preparing a laminated conductive foil in which a first conductive foil and a second conductive foil are laminated, and forming a first separation groove in the first conductive foil excluding at least a region serving as a conductive path. Forming a first conductive path having a curved side surface, and removing a portion of the second conductive foil corresponding to the first separation groove in a thickness direction to leave a connecting portion. Forming a second isolation groove by means of the first conductive path, and simultaneously forming a second conductive path on the back surface of the first conductive path; and electrically connecting a desired circuit element on the desired first conductive path. Fixing the circuit element, forming a connection means for electrically connecting an electrode of the circuit element to a desired first conductive path, and forming the circuit element, the connection means, and the first conductive path. Covering and molding with an insulating resin so as to fill the first and second separation grooves; Removing the connecting portion of the second conductive foil, and a step of separating into individual circuit devices by cutting the insulating resin.
[0029]
First, the first step of the present invention is to prepare a laminated conductive foil 60 in which a first conductive foil 60A and a second conductive foil 60B are laminated as shown in FIG.
[0030]
What is important here is that both conductive foils can be selectively etched and that the resistance value is low. In order to improve the degree of integration, it is also important that a fine pattern can be formed by etching. For example, when patterning the first conductive foil 60A by etching, it is important that the second conductive foil 60B functions as an etching stopper, and conversely, the second conductive foil 60B is etched to form the second conductive foil 60B. When patterning as a path, it is also important that the first conductive foil 60A is not etched.
[0031]
For example, materials having low resistance include Cu, Al, Au, Ag, Pt and the like. Cu and Al are suitable in consideration of cost and workability. Cu is the most adopted material because of its low resistance and low cost, and is a material that can be wet etched. However, it is a material that is difficult to dry-etch.
[0032]
On the other hand, Al is a material that is frequently used for wiring of a semiconductor IC and can be anisotropically etched. Since the side walls can be etched straight, wiring can be formed at a higher density.
[0033]
For example, when using Cu as the first conductive foil, if an Al foil is prepared and Cu is plated on the surface of the Al foil, the thickness of Cu can be adjusted, so that a finer pattern can be formed. Naturally, if the thickness of Cu is reduced, the etching in the lateral direction does not proceed, so that a finer pattern can be formed. When using Al as the first conductive foil 60A, a Cu foil is prepared, and Al is formed on the Cu foil by vapor deposition or sputtering, so that the film thickness of Al can be adjusted. Furthermore, Cl ₂ Gas or Cl ₂ + BCl ₃ Since gas can be used for anisotropic etching, a finer pattern can be obtained.
[0034]
Hereinafter, an Al foil of 10 μm to 300 μm is adopted as the second conductive foil 60 </ b> B, and a Cu plated to about several μm to 20 μm is adopted as the first conductive foil 60 </ b> A. I will explain.
[0035]
The sheet-shaped laminated conductive foil 60 is prepared by being wound in a roll shape with a predetermined width, and may be conveyed to each step described later, or a conductive foil cut to a predetermined size is prepared. , May be transported to each step described later.
[0036]
In the second step of the present invention, as shown in FIGS. 2 and 3, a first separation groove 61 is formed in the first conductive foil 60A except for at least a region to be a conductive path, and the side surface has a curved structure. One conductive path is to be formed.
[0037]
First, as shown in FIG. 2, a photoresist PR (etching resistant mask) is formed on the first conductive foil 60A made of Cu, and the first conductive foil 60A excluding the regions that become the first conductive paths 51A to 51C. Is patterned so that is exposed. Then, as shown in FIG. 3A, etching is performed via the photoresist PR.
[0038]
In this step, the film is non-anisotropically etched by wet etching or dry etching, and has a feature that its side surface is rough and curved.
[0039]
In the case of wet etching, ferric chloride or cupric chloride is used as an etchant, and the conductive foil is dipped in the etchant or the etchant is showered. Here, since the wet etching is generally performed non-anisotropically, the side surface has a curved structure 59. When ferric chloride is used as an etchant, Al does not work as an etching stopper because Al has a higher etching rate than Cu. Therefore, when the first conductive foil 60A is patterned as the first conductive paths 51A to 51C, the Al second conductive foil 60B can integrally support the first conductive paths 51A to 51C. It is necessary to increase the thickness.
[0040]
In the case of dry etching, anisotropic and non-anisotropic etching is possible. At present, it is said that it is impossible to remove Cu by reactive ion etching, and Cu can be removed by sputtering. Further, etching can be performed anisotropically or non-anisotropically depending on sputter etching conditions. By making it non-anisotropic, the side surface of the first separation groove 61 becomes a curved structure 59.
[0041]
Here, an etchant in which Cu is etched and Al is not etched is used, and an etchant in which Al serves as an etching stopper is preferable.
[0042]
In particular, as shown in FIG. 3B, the etching in the horizontal direction is difficult to proceed immediately below the photoresist PR serving as an etching mask, and the portion deeper than that is etched in the horizontal direction. As shown in the figure, if the opening diameter of the opening corresponding to the position becomes smaller from a certain position of the side surface of the first separation groove 61 upward, the first separation groove 61 has a reverse tapered structure, and has a structure having an anchor structure. In addition, by employing a shower ring, etching proceeds in the depth direction and etching in the horizontal direction is suppressed, so that this anchor structure appears remarkably.
[0043]
In FIG. 2, a conductive film having corrosion resistance to an etching solution may be selectively coated instead of the photoresist. When the conductive film is selectively applied to a portion to be a conductive path, the conductive film serves as an etching protection film, and the first separation groove 61 can be etched without using a resist. Materials that can be considered as the conductive film include Ni, Ag, Au, Pt, and Pd. Moreover, these corrosion-resistant conductive films have a feature that they can be used as they are as die pads and bonding pads.
[0044]
For example, the Ag film adheres to Au and also adheres to the brazing material. Therefore, if the Au film is coated on the back surface of the chip, the chip can be thermocompression-bonded to the Ag film on the conductive path 51 as it is, and the chip can be fixed via a brazing material such as solder. Since the Au thin wire can be bonded to the Ag conductive film, wire bonding is also possible. Therefore, there is an advantage that these conductive films can be used as die pads and bonding pads as they are.
[0045]
In the third step of the present invention, as shown in FIG. 4, the second conductive foil 60 </ b> B at a portion corresponding to the first separation groove 61 is partially removed in the thickness direction to leave the connection portion 64 in the second step. Is formed, and at the same time, a second conductive path is formed on the back surface of the first conductive path.
[0046]
In this step, the second conductive foil 60B is half-etched by using the photoresist PR used in the previous step and the first conductive foil 60A in which the first separation groove 61 is formed as a mask to form a second separation groove 62. . Here, etching is performed by using an alkali solution such as sodium hydroxide. Since sodium hydroxide etches Al but does not etch Cu, the second separation groove 62 having the curved structure 63 can be formed without corroding the first conductive paths 51A to 51C.
[0047]
The second separation groove 62 is formed to have a thickness of about half of the thickness of the second conductive foil 60B, and the remaining portion has a role of supporting the conductive path as the connecting portion 64. That is, since the second conductive foil 60B is maintained as a sheet at the connecting portion 64, the first conductive paths 51A to 51C are not individually separated. Therefore, it can be handled as a sheet-shaped laminated conductive foil 60 integrally, and has a feature that when the insulating resin is molded, the work of transporting to the mold and mounting on the mold becomes extremely easy.
[0048]
Note that the second conductive foil 60B separated by the separation groove 62 on the back surface of the first conductive path becomes the second conductive path, and the two form a conductive path.
[0049]
In the fourth step of the present invention, as shown in FIG. 5, a desired circuit element is electrically connected and fixed on a desired first conductive path, and an electrode of the circuit element is connected to the desired first conductive path. Is to form a connecting means for electrically connecting. That is, the circuit elements 52A and 52B are electrically connected and mounted on the first conductive paths 51A to 51C in which the first separation grooves 61 are formed, and are electrically connected by the connection means.
[0050]
The circuit element 52 is a semiconductor element 52A such as a transistor, a diode, or an IC chip, and a passive element 52B such as a chip capacitor or a chip resistor. These elements may be bare chips or sealed chips. Although the thickness is increased, a face-down element (also called a flip chip) such as a CSP or a BGA can be mounted.
[0051]
Here, the bare transistor chip 52A is die-bonded to the first conductive path 51A. Further, the emitter electrode and the first conductive path 51B, and the base electrode and the first conductive path 51B are connected via a thin metal wire 55A fixed by a ball bonding method by thermocompression bonding or a wet bonding method by ultrasonic waves. . A chip capacitor or a passive element is mounted and fixed between the first conductive paths 51B and 51C via a brazing material such as solder or a conductive paste 55B such as Ag paste.
[0052]
When the pattern shown in FIG. 29 is applied in the present embodiment, the bonding pad 26 has a very small size, but is integrated with the second conductive foil 60B as shown in FIG. Therefore, there is an advantage that the energy of the bonding tool can be transmitted, and the bonding property can be improved. Further, in cutting the thin metal wire after bonding, there is a case where the thin metal wire is pulled. At this time, since the bonding pad is formed integrally with the second conductive foil 60B, the phenomenon that the bonding pad floats can be eliminated, and the pull cut property can be improved.
[0053]
In the fifth step of the present invention, as shown in FIG. 6, the insulating resin is coated so as to cover the circuit element, the connecting means and the first conductive path, and to fill the first and second separation grooves 61 and 62. Molding with
[0054]
In this step, the insulating resin 50 is attached to the first conductive paths 51A to 51C, the curved first separation groove 61 and the second separation groove 62. This can be achieved by transfer molding, injection molding, dipping or coating. As the resin material, a thermosetting resin such as an epoxy resin can be realized by transfer molding, and a thermoplastic resin such as a polyimide resin and polyphenylene sulfide can be realized by injection molding.
[0055]
The thickness of the insulating resin 50 coated on the surface of the conductive foil 60 is adjusted so as to cover about 100 μm from the top of the circuit element (here, the top of the fine metal wire 55A). This thickness can be increased or reduced in consideration of strength.
[0056]
Furthermore, since the first separating groove 61 having the curved structure 59 and the second separating groove 62 having the curved structure 63 are filled with the insulating resin 50, an anchor effect is generated in this portion, and the insulating property is reduced. The resin 50 can be prevented from peeling, and conversely, the conductive path 51 separated in a later step can be prevented from coming off.
[0057]
Before coating with the insulating resin 50, for example, a silicone resin or the like may be potted to protect a connection portion of a semiconductor chip or a thin metal wire.
[0058]
The sixth step of the present invention is to remove the connecting portion of the second conductive foil as shown in FIG. That is, there is a step of chemically and / or physically removing the back surface of the second conductive foil 60B and separating the second conductive foil 60B as the conductive path 51. This step can be achieved by polishing, grinding, etching, laser metal evaporation, or the like.
[0059]
In this step, etching is performed using an alkaline solution such as sodium hydroxide. Sodium hydroxide does not etch the first conductive paths 51A to 51C because it etches Al but not Cu.
[0060]
As a result, the structure is such that the second conductive paths 51S to 51U are exposed in the insulating resin 50. Then, the bottom of the second separation groove 62 is exposed.
[0061]
Further, a conductive material such as solder is applied to the exposed second conductive paths 51S to 51U as necessary. When a conductive film is applied to the back surfaces of the second conductive paths 51S to 51U, the conductive film may be formed in advance on the back surface of the conductive foil of FIG. In this case, the portion corresponding to the conductive path may be selectively applied. The deposition method is, for example, plating. The conductive film is preferably made of a material having resistance to etching.
[0062]
The seventh step of the present invention is to separate the insulating resin 50 into individual circuit devices as shown in FIG.
[0063]
In this embodiment, only a circuit device in which a transistor and a chip resistor are mounted on a conductive path is shown. However, in practice, a large number of circuit devices are arranged in a matrix in a unit of the circuit device. Is placed on top. In this case, the insulating resin 50 filled in the first and second separation grooves 61 and 62 between each unit is cut by a dicing device as shown in FIG. 21 to be separated individually.
[0064]
According to the above manufacturing method, the circuit device 53 in which the first conductive paths 51A to 51C are embedded in the insulating resin 50 and the second conductive paths 51S to 51U are exposed on the back surface of the insulating resin 50 can be realized.
[0065]
The structure of the circuit device of the present invention will be described with reference to FIG.
[0066]
FIG. 8 shows a circuit device 53 having a conductive path 51 embedded in an insulating resin 50, a circuit element 52 fixed on the conductive path 51, and supporting the conductive path 51 with the insulating resin 50. It is shown. Moreover, the side surfaces of the conductive path 51 have curved structures 59 and 63.
[0067]
This structure includes three materials: circuit elements 52A and 52B, a plurality of first conductive paths 51A to 51C and second conductive paths 51S to 51U, and an insulating resin 50 that embeds the first conductive paths 51A to 51C. A first separation groove 61 and a second separation groove 62 filled with the insulating resin 50 are provided between the first conductive paths 51A to 51C and the second conductive paths 51S to 51U. Is provided. The conductive paths 51 of the curved structures 59 and 63 are supported by the insulating resin 50.
[0068]
This circuit device covers the conductive path 51 and is filled and supported integrally with the first and second separation grooves 61 and 62 between the first conductive paths 51A to 51C and the second conductive paths 51S to 51U. Insulating resin 50 to be used.
[0069]
In addition, the space between the conductive paths 51 is filled with the insulating resin 50, so that there is a merit that mutual insulation is achieved.
[0070]
A first separation groove 61 is formed between the first conductive paths 51A to 51C of the curved structure 59, and a second separation groove 62 is formed between the second conductive paths 51S to 51U of the curved structure 63. Is filled with the insulating resin 50, the conductive paths 51 can be prevented from coming off and at the same time, they have the advantage of being insulated from each other.
[0071]
By exposing the second conductive paths 51S to 51U, the back surface of the second conductive path can be connected to the outside, so that the through hole TH of the conventional structure as shown in FIG. 26 can be eliminated.
Second embodiment of the present invention
Next, a method of manufacturing the circuit device 56 having the eaves 58 will be described with reference to FIGS. Except that a conductive film (hereinafter, referred to as a second material) 70 serving as an eave is applied, the structure is substantially the same as that of the first embodiment.
[0072]
The present invention provides a step of preparing a laminated conductive foil in which a first conductive foil and a second conductive foil are laminated, and forming a corrosion-resistant conductive film on at least a region serving as a conductive path on the surface of the first conductive foil. Forming a first separation groove in the first conductive foil excluding at least a region serving as a conductive path to form a first conductive path having a curved side surface; and forming the first separation groove. The second conductive foil at a portion corresponding to the above is partially removed to form a second separation groove while leaving a connecting portion, and at the same time, a second conductive path is formed on the back surface of the first conductive path. A step of electrically connecting and fixing a desired circuit element on a desired first conductive path, and a step of electrically connecting an electrode of the circuit element to the desired first conductive path. Forming means, and covering the circuit element, the connection means and the first conductive path, Molding the first and second conductive paths with the insulating resin so as to fill the first and second separation grooves, and connecting the first and second conductive paths to the second conductive foil. And removing step.
[0073]
First, in the first and second steps of the present invention, as shown in FIG. 9, a laminated conductive foil in which a first conductive foil and a second conductive foil are laminated is prepared, and at least the surface of the first conductive foil is provided. An object of the present invention is to form a corrosion-resistant conductive film in a region serving as a conductive path.
[0074]
As shown in FIG. 9, a laminated conductive foil 60 in which a second material 70 having a small etching rate is coated on a first conductive foil 60A made of a first material is prepared.
[0075]
For example, when Ni is deposited on a Cu foil, Cu and Ni can be etched at once with ferric chloride, cupric chloride, or the like, and Ni is formed as eaves 58 due to a difference in etching rate. is there. The thick solid line is the conductive film 70 made of Ni, and its thickness is preferably about 1 to 10 μm. Also, the eaves 58 are more likely to be formed as the Ni film thickness is larger.
[0076]
The second material may cover a material which can be selectively etched with the first material. In this case, first, a coating made of the second material is patterned so as to cover the formation regions of the first conductive paths 51A to 51C, and the first conductive foil 60A made of the first material is formed using the coating as a mask. This is because the eaves 58 can be formed by etching.
[0077]
In the third step of the present invention, as shown in FIGS. 10 and 11, a first separation groove is formed in the first conductive foil except for at least a region to be a conductive path, and the first side of the first conductive foil has a curved structure. To form the conductive path.
[0078]
As shown in FIG. 10, a photoresist PR is formed on Ni70, and the photoresist PR is patterned so as to expose Ni70 excluding the regions serving as the first conductive paths 51A to 51C. As shown in FIG. Etching may be carried out through the gap.
[0079]
As described above, when etching is performed using an etchant of ferric chloride or cupric chloride or the like, since the etching rate of Ni70 is lower than the etching rate of Cu60, the eaves 58 appear as the etching proceeds.
[0080]
In the fourth step of the present invention, as shown in FIG. 12, a second separation groove is formed by partially removing a portion of the second conductive foil corresponding to the first separation groove and leaving a connecting portion. At the same time, a second conductive path is formed on the back surface of the first conductive path.
[0081]
This step is the same as the third step (FIG. 4) of the above-described first embodiment, and a description thereof will not be repeated.
[0082]
In the fifth step of the present invention, as shown in FIG. 13, a desired circuit element is electrically connected to and fixed on a desired first conductive path, and an electrode of the circuit element is connected to the desired first conductive path. Is to form a connecting means for electrically connecting.
[0083]
This step is the same as the fourth step (FIG. 5) of the above-described first embodiment, and a description thereof will be omitted.
[0084]
In the sixth step of the present invention, as shown in FIG. 14, the circuit element, the connecting means and the first conductive path are covered and molded with an insulating resin so as to fill the first and second separation grooves. , And the first and second conductive paths are fitted to the insulating resin.
[0085]
This step is the same as the fifth step (FIG. 6) of the first embodiment described above, and the description is omitted.
[0086]
The seventh step of the present invention is to remove the connecting portion of the second conductive foil as shown in FIG.
[0087]
This step is the same as the sixth step (FIG. 7) of the first embodiment described above, and the description is omitted.
[0088]
The eighth step of the present invention is to separate the insulating resin 50 into individual circuit devices as shown in FIG.
[0089]
This step is the same as the seventh step (FIG. 8) of the first embodiment described above, and the description is omitted.
[0090]
As described above, by generating the triple anchor effect by the eaves 58 and the curved structures 59 and 63, it is possible to prevent the conductive paths from coming off or warping.
Third embodiment of the present invention
Subsequently, a circuit in which IC circuits composed of conductive paths including a plurality of types of circuit elements, wirings, die pads, bonding pads, and the like are arranged in a matrix as one unit, and individually separated after sealing to form an IC circuit A method of manufacturing the device will be described with reference to FIGS. In addition, since this manufacturing method is almost the same as the first embodiment and the second embodiment, the same parts will be briefly described.
[0091]
First, as shown in FIG. 17, a sheet-shaped laminated conductive foil 60 is prepared.
[0092]
When forming the first and second separation grooves 61 and 62 in the step of FIG. 19, the second conductive foil 60B needs to have a film thickness that can support the first conductive path so as not to be separated. is there. Here, one is Al and the other is Cu, and either may be on top. Further, the sheet-shaped laminated conductive foil 60 is prepared by being wound into a roll with a predetermined width, and may be conveyed to each step described later, or a conductive foil cut to a predetermined size is prepared, It may be transported to each step described later.
[0093]
Subsequently, there is a step of removing the first conductive foil 60A excluding at least a region to be the first conductive paths 51A to 51C.
[0094]
First, as shown in FIG. 18, a photoresist PR is formed on the first conductive foil 60A, and the photoresist PR is formed such that the first conductive foil 60A excluding the regions to be the first conductive paths 51A to 51C is exposed. Is patterned. Then, as shown in FIG. 19, etching may be performed via the photoresist PR.
[0095]
The side surface of the first separation groove 61 formed by etching is roughened, so that the adhesion to the insulating resin 50 is improved.
[0096]
The side wall of the first separation groove 61 is curved because it is non-anisotropically etched. For this removing step, wet etching or dry etching can be adopted. The curved structure provides a structure in which an anchor effect is generated. (For details, refer to the first embodiment which describes a method of manufacturing a circuit device.)
In FIG. 18, a conductive film having corrosion resistance to an etching solution may be selectively coated instead of the photoresist PR. When the conductive film is selectively applied to the portion serving as the first conductive path, the conductive film serves as an etching protection film, and the separation groove can be etched without employing a resist.
[0097]
Further, the second separation foil 62 is formed by half-etching the second conductive foil 60B through the first separation groove 61 with an etchant that does not etch the first conductive foil 60A. At this time, a part of the second conductive foil 60B is left as the connection part 64, and supports the whole so as not to be separated separately.
[0098]
Subsequently, as shown in FIG. 20, there is a step of electrically connecting and mounting the circuit element 52A to the first conductive foil 60A in which the first separation groove 61 is formed.
[0099]
The circuit element 52A is a transistor, a diode, a semiconductor element such as an IC chip, or a passive element such as a chip capacitor or a chip resistor. Although the thickness is increased, a face-down semiconductor element (flip chip) such as CSP or BGA can also be mounted.
[0100]
Here, the bare transistor chip 52A is die-bonded to the conductive path 51A, and the emitter electrode and the first conductive path 51B, and the base electrode and the first conductive path 51B are connected via the thin metal wire 55A.
[0101]
Further, as shown in FIG. 21, there is a step of attaching the insulating resin 50 to the laminated conductive foil 60 and the first and second separation grooves 61 and 62. This can be achieved by transfer molding, injection molding, dipping or coating.
[0102]
In the present embodiment, the thickness of the insulating resin coated on the surface of the laminated conductive foil 60 is adjusted so as to cover about 100 μm from the top of the circuit element. This thickness can be increased or reduced in consideration of strength.
[0103]
In addition, the first and second separation grooves 61 and 62 are formed such that the first conductive foil 60A serves as the first conductive paths 51A to 51C because the second conductive foil 60B remains in a sheet shape at the connection portion 64. Not individually separated. Therefore, it can be handled as a sheet-shaped laminated conductive foil 60 integrally, and has a feature that when the insulating resin is molded, the work of transporting to the mold and mounting on the mold becomes extremely easy.
[0104]
Subsequently, as shown in FIG. 22, there is a step of chemically and / or physically removing the back surface of the second conductive foil 60B at the position shown by the dotted line and separating it as the conductive path 51. Here, this step is performed by etching. As a result, the structure is such that the second conductive paths 51S to 51U are exposed on the back surface of the insulating resin 50.
[0105]
Further, a conductive material such as solder is applied to the exposed second conductive paths 51S to 51U.
[0106]
Finally, as shown in FIG. 23, there is a step of separating each circuit element to complete a circuit device.
[0107]
The separation line is located at the arrow and can be realized by dicing, cutting, pressing, chocolate break, or the like. When a chocolate break is used, a protrusion may be formed on the mold so that a groove is formed in the separation line when the insulating resin is coated.
[0108]
In particular, dicing is preferred because it is frequently used in a normal method of manufacturing a semiconductor device and can separate very small objects.
The manufacturing method of the present invention described in the first to third embodiments can implement a complicated pattern as shown in FIG. In particular, the wiring that is bent and formed integrally with the bonding pad 26 and has the other end electrically connected to the circuit element has a narrow width and a long length. Therefore, warpage due to heat is very large, and peeling is a problem in the conventional structure. However, in the present invention, since the wiring is embedded and supported in the insulating resin, it is possible to prevent the wiring itself from being warped, peeled, or pulled out. Also, the bonding pad itself has a small plane area, and in the conventional structure, the bonding pad is peeled off. However, in the present invention, the bonding pad is embedded in the insulating resin as described above, and furthermore, the insulating resin has an anchor effect. Since it is supported with its curved structure, it has an advantage that it can be prevented from coming off.
[0109]
Further, there is an advantage that a circuit device in which a circuit is embedded in the insulating resin 50 can be realized. In terms of the conventional structure, it is as if a circuit is incorporated in a printed circuit board or a ceramic substrate. This will be described in a later mounting method.
[0110]
The right side of FIG. 30 shows a flow that briefly summarizes the present invention. 9 steps of preparing laminated conductive foil, plating of Ag or Ni, etching of first conductive foil, etching of second conductive foil, die bonding, wire bonding, transfer molding, back surface treatment of conductive path and dicing Can be realized. Moreover, all processes can be performed in-house without supplying a supporting substrate from a manufacturer.
Embodiments explaining types of circuit devices and methods of mounting them
FIG. 24 shows a circuit device 81 on which a face-down type circuit element 80 is mounted. As the circuit element 80, a bare semiconductor chip, a CSP or a BGA (flip chip) whose surface is sealed, and the like are applicable. FIG. 25 shows a circuit device 83 on which a passive element 82 such as a chip resistor or a chip resistor is mounted. Since they are thin and sealed with an insulating resin, they have excellent environmental resistance.
[0111]
FIG. 26 illustrates a real layer structure. First, FIG. 26A shows a case where the circuit devices 53, 56, 81, and 83 of the present invention described so far are mounted on conductive paths 85 formed on a mounting substrate 84 such as a printed substrate, a metal substrate, or a ceramic substrate. .
[0112]
In particular, since the conductive path 51A to which the back surface of the semiconductor chip 52 is fixed is thermally coupled to the conductive path 85 of the mounting board 84, heat of the circuit device can be radiated through the conductive path 85. . When a metal substrate is used as the mounting substrate 84, the heat dissipation of the metal substrate is also helped, and the temperature of the semiconductor chip 52 can be further reduced. Therefore, the driving capability of the semiconductor chip can be improved.
[0113]
For example, power MOS, IGBT, SIT, transistor for driving a large current, IC (MOS type, BIP type, Bi-CMOS type) memory element for driving a large current are suitable.
[0114]
As the metal substrate, an Al substrate, a Cu substrate, and an Fe substrate are preferable, and an insulating resin and / or an oxide film are formed in consideration of a short circuit with the conductive path 85.
[0115]
FIG. 26B shows an example in which the circuit device 90 is used as the substrate 84 in FIG. 26A. This is the most important feature of the present invention. That is, in the conventional printed circuit board and ceramic substrate, the through hole TH is formed in the substrate at most, but the present invention has a feature that a substrate module having a built-in IC circuit can be realized. For example, at least one circuit (may be built in as a system) is built in a printed circuit board.
[0116]
Conventionally, a printed circuit board, a ceramic substrate, or the like is required as a support substrate, but the present invention can realize a substrate module that does not require the support substrate. This can reduce the thickness and the weight as compared with a hybrid substrate composed of a printed substrate, a ceramic substrate or a metal substrate.
[0117]
In addition, since the circuit device 90 can be used as a support substrate and circuit elements can be mounted on exposed conductive paths, a high-performance board module can be realized. In particular, if the present circuit device is used as a support substrate and the present circuit device 91 is mounted thereon as an element, a lighter and thinner substrate module can be realized.
[0118]
Therefore, according to these mounting modes, a small and lightweight electronic device in which this module is mounted can be realized.
[0119]
The hatched portion indicated by reference numeral 93 is an insulating film. For example, a polymer film such as a solder resist is preferable. By forming this, a short circuit between the conductive path embedded in the substrate 90 and the electrode formed on the circuit element 91 or the like can be prevented.
Further, advantages of the circuit device will be described with reference to FIG. In the conventional mounting method, a semiconductor maker forms a package type semiconductor device and a flip chip, and a set maker mounts a semiconductor device supplied by a semiconductor maker and a passive element supplied by a component maker on a printed circuit board. Then, this was assembled into a set as a module to form an electronic device. However, since the circuit device itself can be used as a mounting substrate, a semiconductor maker can complete a mounting substrate module using a post-process and supply it to a set maker. Therefore, the set maker can largely omit the device mounting on this substrate.
[0120]
【The invention's effect】
As is apparent from the above description, according to the present invention, the circuit device is configured with the minimum necessary amounts of the circuit device, the conductive path, and the insulating resin, and the circuit device has no waste in resources. Therefore, there is no extra component until completion, and a circuit device that can greatly reduce the cost can be realized. Further, by setting the coating thickness of the insulating resin and the thickness of the conductive foil to optimal values, it is possible to realize a very small, thin, and lightweight circuit device. Furthermore, since the wiring in which the phenomenon of warpage or peeling is remarkable is supported by being embedded in the insulating resin, these problems can be solved.
[0121]
Further, since only the back surface of the conductive path is exposed from the insulating resin, the back surface of the conductive path can be immediately used for connection with the outside, and the advantage that the back electrode and the through hole of the conventional structure as shown in FIG. Having.
[0122]
In addition, the anchor effect can be provided by the fact that the side surface of the conductive path has a curved structure and / or by forming a coating made of the second material on the surface of the conductive path, the eaves attached to the conductive path can be formed. This can prevent the conductive path from warping or coming off.
[0123]
In the method for manufacturing a circuit device according to the present invention, the conductive foil itself serving as the material of the conductive path is made to function as a support substrate, and the conductive foil is used until the separation groove is formed or the circuit element is mounted and the insulating resin is attached. When the whole is supported and the conductive foil is separated as each conductive path, an insulating resin is used as a supporting substrate to function. Therefore, the circuit element, the conductive foil, and the insulating resin can be manufactured with the minimum necessary. As described in the conventional example, a support substrate is not required for originally configuring the circuit device, and the cost can be reduced. In addition, there is no need for a support substrate, the conductive paths are embedded in the insulating resin, and the thickness of the insulating resin and the conductive foil can be adjusted, so that an extremely thin circuit device can be formed. There is also. Further, a curved structure can be formed in the step of forming the separation groove, and a structure having an anchor effect can be realized at the same time.
[0124]
Further, as is clear from FIG. 30, since the step of forming a through hole, the step of printing a conductor (in the case of a ceramic substrate), and the like can be omitted, the manufacturing process can be greatly shortened as compared with the related art, and the entire process can be manufactured internally. . In addition, no frame mold is required at all, and this is a manufacturing method with a very short delivery time.
[0125]
Next, since the conductive paths can be handled without being individually separated, workability is improved in a later step of coating the insulating resin.
[0126]
Finally, the circuit device can be used as a support substrate and circuit elements can be mounted on exposed conductive paths, so that a high-performance board module can be realized. In particular, if the present circuit device is used as a support substrate and the present circuit device 91 is mounted thereon as an element, a lighter and thinner substrate module can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a first embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 2 is a diagram illustrating a first embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 3 is a diagram illustrating a first embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 4 is a diagram illustrating a first embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 5 is a diagram illustrating a first embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 6 is a diagram illustrating a first embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 7 is a diagram illustrating a first embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 8 is a diagram illustrating a circuit device manufacturing method according to a first embodiment of the present invention.
FIG. 9 is a diagram illustrating a second embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 10 is a diagram illustrating a circuit device manufacturing method according to a second embodiment of the present invention.
FIG. 11 is a diagram illustrating a second embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 12 is a diagram illustrating a circuit device manufacturing method according to a second embodiment of the present invention.
FIG. 13 is a diagram illustrating a second embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 14 is a diagram illustrating a second embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 15 is a diagram illustrating a second embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 16 is a diagram illustrating a circuit device manufacturing method according to a second embodiment of the present invention.
FIG. 17 is a diagram illustrating a third embodiment of the method of manufacturing a circuit device according to the present invention.
FIG. 18 is a diagram illustrating a circuit device manufacturing method according to a third embodiment of the present invention.
FIG. 19 is a diagram illustrating a circuit device manufacturing method according to a third embodiment of the present invention.
FIG. 20 is a diagram illustrating a third embodiment of the method of manufacturing a circuit device according to the present invention.
FIG. 21 is a diagram illustrating a third embodiment of the method of manufacturing a circuit device according to the present invention.
FIG. 22 is a diagram illustrating a third embodiment of a method of manufacturing a circuit device according to the present invention.
FIG. 23 is a diagram illustrating a third embodiment of the method of manufacturing a circuit device according to the present invention.
FIG. 24 is a diagram illustrating a circuit device of the present invention.
FIG. 25 is a diagram illustrating a circuit device of the present invention.
FIG. 26 is a diagram illustrating a mounting structure of the circuit device of the present invention.
FIG. 27 is a diagram illustrating a mounting structure of a conventional circuit device.
FIG. 28 is a diagram illustrating a conventional circuit device.
FIG. 29 is a diagram illustrating a method for manufacturing a conventional circuit device.
FIG. 30 is a diagram illustrating a method for manufacturing a circuit device according to the related art and the present invention.
FIG. 31 is a pattern diagram of an IC circuit applied to the conventional and the circuit devices of the present invention.
FIG. 32 is a diagram illustrating the positioning of a semiconductor maker and a set maker.
[Explanation of symbols]
50 Insulating resin
51 Conductive path
52 circuit elements
53 Circuit device
58 eaves
60 laminated conductive foil
60A first conductive foil
60B second conductive foil
61 1st separation groove
62 Second separation groove

Claims (15)

Preparing a laminated conductive foil in which a first conductive foil and a second conductive foil are laminated;
Forming a first separation groove in the first conductive foil excluding at least a region serving as a conductive path to form a first conductive path having a curved side surface;
A portion of the second conductive foil corresponding to the first separation groove is partially removed in a thickness direction to form a second separation groove while leaving a connection portion, and at the same time, a back surface of the first conductive path. Forming a second conductive path at
Electrically connecting and fixing a desired circuit element on a desired first conductive path;
Covering the circuit element and the first conductive path, and molding with an insulating resin so as to fill the first and second separation grooves;
Removing the connection portion of the second conductive foil. Preparing a laminated conductive foil in which a first conductive foil and a second conductive foil are laminated;
Forming a corrosion-resistant conductive film on at least a region serving as a conductive path on the surface of the first conductive foil;
Forming a first separation groove in the first conductive foil excluding at least a region serving as a conductive path to form a first conductive path having a curved side surface;
A portion of the second conductive foil corresponding to the first separation groove is partially removed to form a second separation groove leaving a connection portion, and at the same time, a second separation groove is formed on the back surface of the first conductive path. Forming a conductive path of
Electrically connecting and fixing a desired circuit element on a desired first conductive path;
Forming connection means for electrically connecting the electrodes of the circuit element and the desired first conductive path;
The circuit element, the connection means and the first conductive path are covered, and molded with an insulating resin so as to fill the first and second separation grooves. A step of fitting an insulating resin;
Removing the connection portion of the second conductive foil. Preparing a laminated conductive foil in which a first conductive foil and a second conductive foil are laminated;
Forming a first separation groove in the first conductive foil excluding at least a region serving as a conductive path to form a first conductive path having a curved side surface;
A portion of the second conductive foil corresponding to the first separation groove is partially removed in a thickness direction to form a second separation groove while leaving a connection portion, and at the same time, a back surface of the first conductive path. Forming a second conductive path at
Electrically connecting and fixing a desired circuit element on a desired first conductive path;
Forming connection means for electrically connecting the electrodes of the circuit element and the desired first conductive path;
A step of covering the circuit element, the connection means and the first conductive path, and molding with an insulating resin so as to fill the first and second separation grooves;
Removing the connecting portion of the second conductive foil;
Cutting the insulating resin to separate into individual circuit devices.
A method for manufacturing a circuit device, comprising: Preparing a laminated conductive foil in which a first conductive foil and a second conductive foil are laminated;
Forming a corrosion-resistant conductive film on at least a region serving as a conductive path on the surface of the first conductive foil;
Forming a first separation groove in the first conductive foil excluding at least a region serving as a conductive path to form a first conductive path having a curved side surface;
A portion of the second conductive foil corresponding to the first separation groove is partially removed to form a second separation groove leaving a connection portion, and at the same time, a second separation groove is formed on the back surface of the first conductive path. Forming a conductive path of
Electrically connecting and fixing a desired circuit element on a desired first conductive path;
Forming connection means for electrically connecting the electrodes of the circuit element and the desired first conductive path;
The circuit element, the connection means and the first conductive path are covered, and molded with an insulating resin so as to fill the first and second separation grooves. A step of fitting an insulating resin;
Removing the connecting portion of the second conductive foil;
Cutting the insulating resin to separate into individual circuit devices. 5. The method according to claim 1, wherein the first conductive foil and the second conductive foil are etched with different etchants to form the first separation groove and the second separation groove. Or a method for manufacturing a circuit device. The first conductive foil is formed of aluminum, and the second conductive foil is formed of one of copper and iron-nickel. A method for manufacturing a circuit device. 7. The method according to claim 6, wherein the laminated conductive foil is formed of the second conductive foil which is formed by plating the first conductive foil made of aluminum with copper. 5. The method according to claim 2, wherein the conductive film is formed by plating with nickel, gold, or silver. The method according to claim 2, wherein the conductive film is used as a part of a mask when forming the first isolation groove. 5. The circuit according to claim 1, wherein the first conductive foil on which the first separation groove is formed is used as a mask when forming the second separation groove. Device manufacturing method 5. The circuit device according to claim 1, wherein one or both of a semiconductor bare chip, a flip chip, a chip circuit component, a package type semiconductor element, and a CSP are fixed to the circuit element. Manufacturing method. The method according to claim 2, wherein the connection unit is formed by wire bonding or a brazing material. The method according to claim 1, wherein the insulating resin is attached by transfer molding. 5. The method for manufacturing a circuit device according to claim 3, wherein the circuit device is separated into individual circuit devices by dicing. The method according to claim 1, wherein the conductive path forms at least a wiring.

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