JP4748892B2 - Circuit device manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a circuit device and a method for manufacturing the circuit device, and more particularly to a thin circuit device that eliminates the need for a support substrate and has enhanced adhesion strength with an insulating resin layer to be sealed and a method for manufacturing the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a circuit device set in an electronic device is used in a mobile phone, a portable computer, and the like.
[0003]
For example, a semiconductor device as an example of a circuit device will be described. As a general semiconductor device, there is a package type semiconductor device sealed by a conventional transfer mold. This semiconductor device is mounted on a printed circuit board PS as shown in FIG.
[0004]
In this package type semiconductor device, the periphery of the semiconductor chip 2 is covered with a resin layer 3, and lead terminals 4 for external connection are led out from the side of the resin layer 3.
[0005]
However, the package type semiconductor device 1 has lead terminals 4 protruding from the resin layer 3 and has a large overall size, which does not satisfy the miniaturization, thickness reduction, and weight reduction.
[0006]
Therefore, various companies have competed to develop various structures to achieve miniaturization, thinning, and weight reduction, and recently called CSP (chip size package), wafer scale CSP equivalent to chip size, or chip size A slightly larger CSP has been developed.
[0007]
FIG. 16 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 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 the second electrode 8 and the second back electrode 11 through the through hole TH. Further, the bare transistor chip T is fixed to the die pad 9, the emitter electrode of the transistor and the first electrode 7 are connected via the bonding wire 12, and the base electrode of the transistor and the second electrode 8 are connected to the bonding 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]
The CSP 6 employs the glass epoxy substrate 5, but unlike the wafer scale CSP, the extending structure from the chip T to the backside 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 the printed circuit board PS as shown in FIG. The printed circuit board PS is provided with electrodes and wirings constituting an electric circuit, and the CSP 6, the package type semiconductor device 1, the chip resistor CR, the chip capacitor CC, and the like are electrically connected and fixed.
[0011]
And the circuit comprised with this printed circuit board is attached in various sets.
[0012]
Next, a method for manufacturing the CSP will be described with reference to FIGS.
[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 via an insulating adhesive. (See FIG. 17A above)
Subsequently, the Cu foils 20, 21 corresponding to the first electrode 7, the second electrode 8, the die pad 9, the first back electrode 10 and the second back electrode 11 are coated with an etching resistant resist 22, The Cu foils 20 and 21 are patterned. Patterning may be performed separately for the front and back sides. (See FIG. 17B 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 through the through hole TH. (See FIG. 17C above)
Further, although omitted in the drawing, the first electrode 7 and the second electrode 8 which are bonding posts are plated with Ni, and the die pad 9 which is a die bonding post is plated with Au, so that the transistor chip T is die bonded. To do.
[0014]
Finally, the emitter electrode and the first electrode 7 of the transistor chip T, the base electrode of the transistor chip T and the second electrode 8 are connected via the bonding wire 12 and covered with the resin layer 13. (See FIG. 17D above)
With the above manufacturing method, a CSP type electric element employing the support substrate 5 is completed. This manufacturing method is the same even if a flexible sheet is adopted as the support substrate.
[0015]
On the other hand, a manufacturing method employing a ceramic substrate is shown in the flow of FIG. After preparing the ceramic substrate as the support substrate, through holes are formed, and then the front and back electrodes are printed and sintered using a conductive paste. After that, it is the same as the manufacturing method of FIG. 16 until the resin layer of the previous manufacturing method is coated. However, the ceramic substrate is very brittle, and unlike a flexible sheet or a glass epoxy substrate, it is easily chipped. There is a problem that can not be molded. Therefore, the potting resin is potted and cured, and then polishing for flattening the sealing resin is performed, and finally, the dicing apparatus is used for individual separation.
[0016]
[Problems to be solved by the invention]
In FIG. 16, the transistor chip T, the connecting means 7 to 12 and the resin layer 13 are necessary components for electrical connection with the outside and protection of the transistor. It has been difficult to provide a circuit element that can be made thinner, thinner and lighter.
[0017]
Moreover, the glass epoxy board | substrate 5 used as a support substrate is an essentially unnecessary thing as mentioned above. However, since the electrodes are bonded together in the manufacturing method, it is adopted as a support substrate, and the glass epoxy substrate 5 cannot be eliminated.
[0018]
For this reason, the use of the glass epoxy substrate 5 increases the cost. Further, since the glass epoxy substrate 5 is thick, it becomes thick as a circuit element, and there is a limit to miniaturization, thickness reduction, and weight reduction.
[0019]
Furthermore, a glass epoxy substrate or a ceramic substrate always requires a through-hole forming process for connecting electrodes on both sides, and the manufacturing process becomes long and is not suitable for mass production.
[0020]
[Means for Solving the Problems]
The present invention has been made in view of the above-described many problems, and includes a plurality of conductive patterns of each mounting portion electrically separated by a separation groove, and a thermosetting resin that fills the separation groove and covers the surface of the conductive pattern. A layer, a circuit element fixed on the thermosetting resin layer, an insulating resin covering the circuit element and integrally supporting the conductive pattern bonded to the thermosetting resin layer, and the conductive pattern And an external electrode with the back surface exposed.
[0021]
In the present invention, by providing a thermosetting resin layer that fills the separation groove and covers the surface of the conductive pattern, the bonding with the insulating resin that covers the circuit element is strengthened, and the size and thickness of the good sealing structure are reduced. A weight-reduced circuit device can be realized and conventional problems can be solved. In addition, by providing an external electrode that leaves the conductive pattern thick, a circuit device with extremely high heat dissipation can be realized.
[0022]
In the manufacturing method of the present invention, a step of preparing a conductive foil, forming a conductive pattern by forming a separation groove shallower than the thickness of the conductive foil on the conductive foil excluding at least a region to be a conductive pattern, A step of filling the separation groove and covering the surface of the conductive pattern with a thermosetting resin layer; a step of selectively removing the portion of the thermosetting resin layer connecting the electrodes of the circuit elements on the conductive pattern; Fixing the circuit element on the thermosetting resin layer; forming a connection means for electrically connecting the electrode of the circuit element and the desired conductive pattern; covering the circuit element; A step of bonding with a thermosetting resin layer and molding with an insulating resin, and a step of removing the conductive foil left in the separation groove and forming an external electrode protruding from the back surface of the thermosetting resin layer; To have And butterflies.
[0023]
In this manufacturing method, since the thermosetting resin layer is embedded in the separation groove and bonded to the insulating resin, the adhesive strength between the insulating resin and the conductive pattern is increased, and a good sealing structure can be obtained and the conventional problems are solved. can do. Further, by removing the conductive foil remaining on the separation groove, an external electrode protruding from the back surface of the thermosetting resin layer can be easily formed, and a circuit device rich in heat dissipation can be manufactured.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment of the circuit device of the present invention
The circuit device of the present invention will be described with reference to FIG.
[0025]
The circuit device according to the present invention includes a plurality of conductive patterns of each mounting portion electrically separated by a separation groove, a thermosetting resin layer that fills the separation groove and covers the surface of the conductive pattern, and the thermosetting A circuit element fixed on a desired conductive pattern exposed from the resin layer; an insulating resin that integrally covers the conductive pattern that covers the circuit element and is bonded to the thermosetting resin layer; It consists of an external electrode with the back surface of the pattern exposed.
[0026]
In FIG. 1, a conductive pattern 51 is embedded in a thermosetting resin layer 50A, and a circuit element 52 is fixed on the conductive pattern 51, and an insulating resin 50B bonded to the thermosetting resin layer 50A. A circuit device 53 configured to support the conductive pattern 51 is shown.
[0027]
This structure is composed of four materials, that is, a circuit element 52, a plurality of conductive patterns 51, a thermosetting resin layer 50A that embeds the conductive patterns 51, and an insulating resin 50B that is bonded thereto. A separation groove 61 filled with the thermosetting resin layer 50A is provided. The conductive pattern 51 is supported by the thermosetting resin layer 50A and the insulating resin 50B.
[0028]
As the thermosetting resin layer 50 </ b> A that is a feature of the present invention, a thermosetting resin such as an epoxy resin is used, and is provided so as to fill the separation groove 61 and cover the surface of the conductive pattern 51. This thermosetting resin layer 50A is casted with a liquid material obtained by dissolving a thermosetting resin in an organic solvent, applied to the surface of the separation groove 61 and the conductive pattern 51, semi-cured, and after the organic solvent has been blown off, is finally cured. Formed. Further, it is preferable that a thermal expansion coefficient with the conductive pattern 51 is relaxed by mixing a filler such as silica or alumina in the thermosetting resin layer 50A. In general, the thermal expansion coefficient of the epoxy resin is 50 ppm / ° C., the thermal expansion coefficient of the epoxy resin containing the filler is 15 to 30 ppm / ° C., and the thermal expansion coefficient of copper forming the conductive pattern 51 is 18 ppm / ° C. Since it is ° C., the mismatch of the thermal expansion coefficient between the epoxy resin and copper can be improved.
[0029]
In addition, since the thermosetting resin layer 50A is filled in the separation groove 61 in a liquid state, it can be in close contact with the inner wall of the separation groove 61 because of its low viscosity compared to the transfer-molded epoxy resin, and the adhesive strength between both is greatly increased. Can be increased.
[0030]
Further, the thermosetting resin layer 50A may be a method in which a semi-cured sheet-like film is heat-pressed and main-cured to adhere to the separation groove 61 and the conductive pattern 51 surface with a molten epoxy resin.
[0031]
As the insulating resin 50B, a thermosetting resin such as an epoxy resin or a thermoplastic resin such as polyphenylene sulfide can be used. As the insulating resin, any resin can be adopted as long as it is a resin that can be hardened using a mold, a resin that can be coated by dipping or coating. However, considering the bonding strength with the thermosetting resin layer 50A, the same kind of resin is preferable, and therefore the thermosetting resin such as an epoxy resin is used as the insulating resin 50B.
[0032]
As the conductive pattern 51, a conductive foil mainly made of Cu, a conductive foil mainly made of Al, or a conductive foil made of an alloy such as Fe-Ni can be used. Of course, other conductive materials are possible, and a conductive material that can be etched and a conductive material that evaporates with a laser are particularly preferable.
[0033]
As the connection means of the circuit element 52, a bonding wire 55 is used in the face-up structure, and a conductive ball made of a brazing material, a flat conductive ball, or a soldering material such as solder is used in the face-down structure. These connection means are selected depending on the type of the circuit element 52 and the mounting form of the circuit element 52.
[0034]
The conductive pattern 51 to which the bonding wire 55 or the brazing material is fixed is selectively exposed from the thermosetting resin layer 50A, and a conductive film 54 is provided on the exposed conductive pattern 51 surface. The material considered as the conductive film 54 is Ag, Au, Pt, Pd, or the like, and is coated by low vacuum such as vapor deposition, sputtering, CVD, or deposition under high vacuum, plating, or sintering.
[0035]
The external electrode 56 is a feature of the present invention, and is formed using the conductive foil 60 left below the separation groove 61 of the conductive pattern 51, and has a shape protruding from the back surface of the thermosetting resin layer 50A. Formed. Therefore, the external electrode 56 is an electrode protruding by about 100 μm using a part of the conductive foil 60. Therefore, as shown in FIG. 1A, the brazing material 57 such as solder attached to the external electrode 56 goes to the side surface of the external electrode 56, and the fixing strength of the external electrode 56 to the conductive path of the printed circuit board is increased. .
[0036]
In addition, since the conductive pattern 51 to which a semiconductor chip or the like that generates heat is fixed constitutes a heat sink having a thickness of the conductive foil 60 together with the external electrode 56A, a structure with extremely low thermal resistance can be provided.
[0037]
Further, as shown in FIG. 1B, a land grid array (LGA) structure can be realized if a thin gold plating layer 57 'is applied on the surface of the external electrode 56, so that the bump electrode is formed by performing a special plating process. Is no longer necessary.
[0038]
In this circuit device, since the conductive pattern 51 is supported by the thermosetting resin layer 50A and the insulating resin 50B, a support substrate is not required. This configuration is a feature of the present invention. As described in the section of the prior art, since the conductive path of the conventional circuit device is supported by the support substrate or supported by the lead frame, a configuration that may be unnecessary is added. However, since this circuit device is composed of the minimum necessary components and does not require a support substrate, it is characterized by being thin and inexpensive.
[0039]
Further, it has a thermosetting resin layer 50A that covers the circuit element 52 and is filled in the separation groove 61 between the conductive patterns 51, and has an advantage that the mutual insulation is achieved.
[0040]
Further, it has a thermosetting resin layer 50A and an insulating resin 50B that cover the circuit element 52 and that are filled in the separation groove 61 between the conductive patterns 51 and expose only the back surface of the conductive pattern 51 and are integrally supported. .
[0041]
The circuit element 52 is fixed to the thermosetting resin layer 50A covering the conductive pattern 51 with an insulating adhesive 58, and the circuit element 52 and the conductive pattern 51 are electrically insulated. As a result, the fine pattern conductive pattern 51 can be freely wired under the circuit element 52, and the degree of freedom of wiring is greatly increased. Each electrode pad of the circuit element 52 is connected by a bonding wire 55 to a conductive film 54 serving as a bonding pad formed by a part of the conductive pattern 51 provided in the periphery. Therefore, the back electrode 56 can be formed also on the conductive pattern 51 under the circuit element 52, and an equivalent two-layer wiring structure can be realized.
[0042]
The point that the back surface of the conductive pattern is exposed is one of the features of the present invention. The back surface of the conductive pattern can serve as an external electrode 56 for connection to the outside, and the external electrode 56 can function as a heat sink or a protruding electrode.
[0043]
Moreover, since the circuit element 52 is fixedly disposed on the thin thermosetting resin layer 50A with the insulating adhesive 58, the heat generated from the circuit element 52 is mounted on the mounting substrate through the conductive pattern 51 through the thermosetting resin layer 50A. Can tell. In particular, it is effective for a semiconductor chip that can improve characteristics such as an increase in driving current by heat radiation.
[0044]
As another example, a UV curable resin may be used instead of the thermosetting resin layer 50A. That is, when a UV curable resin is coated with a vacuum laminator and then UV-irradiated, developed, and fully cured, the UV curable resin can be formed so as to cover the desired surfaces of the separation groove 61 and the conductive pattern 51. The UV curable resin is also an epoxy resin system, and the same effect as the thermosetting resin layer 50A can be obtained.
Embodiment of a method of manufacturing a circuit device of the present invention
First, a method for manufacturing a circuit device of the present invention will be described with reference to FIG.
[0045]
The present invention provides a conductive foil, and forms a conductive pattern by forming a separation groove shallower than the thickness of the conductive foil in the conductive foil in a region excluding the conductive pattern that forms at least a large number of circuit element mounting portions. A step, a step of covering the separation groove and the conductive pattern with a thermosetting resin, a step of exposing a predetermined conductive pattern surface by laser etching, a step of selectively forming a conductive film on the exposed conductive pattern, The step of fixing the circuit element on the thermosetting resin layer of each mounting part, the step of wire bonding the electrode of the circuit element and the conductive film of the conductive pattern, and the circuit element of each mounting part are collectively covered A step of performing a common molding with an insulating resin so as to fill the separation groove, a step of removing the conductive foil in the separation groove portion, and a plurality of the blocks as the insulating resin. A process of contacting and sticking to the adhesive sheet, a process of measuring characteristics of the circuit elements of each mounting portion of the block in a state of being attached to the adhesive sheet, and a state of being attached to the adhesive sheet And the step of separating the insulating resin of the block by dicing for each mounting portion.
[0046]
The flow shown in FIG. 2 does not match the above-described process, but the conductive pattern is formed by two flows of Cu foil and half etching. The separation groove and the surface of the conductive pattern are covered with the thermosetting resin by the flow of the thermosetting resin. The circuit element is fixed to each mounting portion and the electrodes of the circuit element and the conductive pattern are connected in two flows of die bonding and wire bonding. In the transfer mold flow, a common mold using an insulating resin is performed. In the flow of removing the rear Cu foil, the conductive foil in the separation groove is etched. In the back surface processing flow, the surface treatment of the external electrodes exposed on the back surface is performed. In the flow of the adhesive sheet, a plurality of blocks are attached to the adhesive sheet. In the measurement flow, non-defective product discrimination and characteristic rank classification of circuit elements incorporated in each mounting part are performed. In the dicing flow, the insulating resin is separated into individual circuit elements by dicing.
[0047]
Below, each process of this invention is demonstrated with reference to FIG. 1 and FIGS. 3-13.
[0048]
In the first step of the present invention, as shown in FIGS. 3 to 5, a conductive foil 60 is prepared, and the conductive foil 60 in the region excluding the conductive pattern 51 that forms at least a large number of mounting portions of the circuit elements 52 is conductive. The purpose is to form the separation groove 61 shallower than the thickness of the foil 60 to form the conductive pattern 51 for each block.
[0049]
In this step, first, as shown in FIG. 3A, a sheet-like conductive foil 60 is prepared. The conductive foil 60 is selected in consideration of the adhesiveness, bonding property, and plating property of the brazing material. As the material, a conductive foil mainly composed of Cu, a conductive foil mainly composed of Al, or Fe is used. A conductive foil made of an alloy such as Ni is employed.
[0050]
The thickness of the conductive foil is preferably about 10 μm to 300 μm in consideration of later etching, and a 125 μm copper foil is employed here. However, it is basically good if it is 300 μm or more and 10 μm or less. As will be described later, it is only necessary that the separation groove 61 shallower than the thickness of the conductive foil 60 can be formed.
[0051]
In addition, the sheet-like conductive foil 60 is prepared by being wound into a roll with a predetermined width, for example, 45 mm, which may be conveyed to each step described later, or a strip-shaped cut into a predetermined size. The conductive foil 60 may be prepared and conveyed to each process described later.
[0052]
Specifically, as shown in FIG. 3B, 4 to 5 blocks 62 in which a large number of mounting portions are formed are arranged on the strip-shaped conductive foil 60 so as to be spaced apart. A slit 63 is provided between each block 62 to absorb the stress of the conductive foil 60 generated by the heat treatment in the molding process or the like. In addition, index holes 64 are provided at regular intervals at the upper and lower peripheral ends of the conductive foil 60, and are used for positioning in each step.
[0053]
Subsequently, a conductive pattern 51 for each block is formed.
[0054]
First, as shown in FIG. 4, a photoresist (etching-resistant mask) PR is formed on the Cu foil 60, and the photoresist PR is patterned so that the conductive foil 60 excluding the region to be the conductive pattern 51 is exposed. Then, as shown in FIG. 5A, the conductive foil 60 is selectively etched through the photoresist PR.
[0055]
The depth of the separation groove 61 formed by etching is, for example, 20 to 30 μm, and its side surface is roughened by oxidation treatment or chemical polishing treatment, and the adhesive strength with the thermosetting resin layer 50A is improved. The
[0056]
The side wall of the separation groove 61 is schematically illustrated as a straight line, but has a different structure depending on the removal method. This removal process can employ wet etching, dry etching, laser evaporation, and dicing. In the case of wet etching, ferric chloride or cupric chloride is mainly used as the etchant, and the conductive foil is dipped in the etchant or showered with the etchant. Since wet etching is generally non-anisotropic, the side surface has a curved structure.
[0057]
In the case of dry etching, etching can be performed anisotropically or non-anisotropically. At present, it is said that Cu cannot be removed by reactive ion etching, but it can be removed by sputtering. Etching can be anisotropic or non-anisotropic depending on sputtering conditions.
[0058]
Further, in the laser, the separation groove 61 can be formed by direct laser light irradiation. In this case, the side surface of the separation groove 61 is formed straight.
[0059]
FIG. 5B shows a specific conductive pattern 51. This figure corresponds to an enlarged view of one of the blocks 62 shown in FIG. 3B. One of the portions painted in black is one mounting portion 65, which constitutes the conductive pattern 51. A large number of mounting portions 65 are arranged in a matrix of 5 rows and 10 columns in one block 62. The same conductive pattern 51 is provided every 65. A frame-like pattern 66 is provided around each block, and an alignment mark 67 at the time of dicing is provided inside the pattern slightly apart from the frame-like pattern 66. The frame-like pattern 66 is used for fitting with the mold, and has a function of reinforcing the insulating resin 50 after the back surface etching of the conductive foil 60.
[0060]
The second step of the present invention is to form the thermosetting resin layer 50A so as to cover the surfaces of the separation groove 61 and the conductive pattern 51, as shown in FIG.
[0061]
This process is a process characterized by the present invention. As the thermosetting resin layer 50A, a thermosetting resin such as an epoxy resin is used so that the separation groove 61 is embedded and the surface of the conductive pattern 51 is covered. Provided. This thermosetting resin layer 50A is cast on a liquid material obtained by dissolving a thermosetting resin in an organic solvent, applied to the surface of the separation groove 61 and the conductive pattern 51, and heated at 80 ° C. to 100 ° C. to be semi-cured. After the organic solvent is blown off, it is heated at 150 ° C. to 170 ° C. for about 1.5 hours to be fully cured. Therefore, in the semi-cured state, the thermosetting resin is in a B-stage state and is not thermally cured.
[0062]
Further, it is preferable that a thermal expansion coefficient with the conductive pattern 51 is relaxed by mixing a filler such as silica or alumina in the thermosetting resin layer 50A. In general, the thermal expansion coefficient of the epoxy resin is 50 ppm / ° C., the thermal expansion coefficient of the epoxy resin containing the filler is 15 to 30 ppm / ° C., and the thermal expansion coefficient of copper forming the conductive pattern 51 is 18 ppm / ° C. Since it is ° C., the mismatch of the thermal expansion coefficient between the epoxy resin and copper can be improved.
[0063]
In addition, since the thermosetting resin layer 50A is filled in the separation groove 61 in a liquid state, it can be in close contact with the inner wall of the separation groove 61 because of its low viscosity compared to the transfer-molded epoxy resin, and the adhesive strength between both is greatly increased. Can be increased. As a result, the adhesive strength is secured by the separation groove 61 of about 60 μm so far. However, the separation groove 61 can be reduced to a half depth of 20 to 30 μm due to the improvement of the adhesive strength, and the conductive pattern 51 becomes a fine pattern. The advantage of being formed is obtained.
[0064]
As another method, the thermosetting resin layer 50A is heat-pressed and semi-cured in advance to form a sheet-like thermosetting resin film, which is then cured, and adhered to the surfaces of the separation grooves 61 and the conductive pattern 51 with a molten epoxy resin. A method can also be adopted. Cover the surface of the thermosetting resin film with cushion paper, 1cm ² This is hardened in a state where the surface of the separation groove 61 and the conductive pattern 51 is covered with an epoxy resin which is pressed at a pressure of 100 kg and heated at 150 to 170 ° C. and melted.
[0065]
In this step, the inner wall of the separation groove 61 is oxidized in order to increase the adhesive strength between the separation groove 61 and the thermosetting resin layer 50A, or the wall surface of the separation groove 61 is formed using an organic acid etching solution. It is better to roughen by chemical polishing. As an organic acid-based etching solution, CZ-8100 manufactured by MEC Co., Ltd. is used and immersed in this etching solution for several minutes to form irregularities of about 1 to 2 μm on the surface. Thereby, since the inner wall surface of the separation groove 61 is roughened, the adhesive strength between the separation groove 61 and the thermosetting resin layer 50A can be increased.
[0066]
In this step, a UV curable resin may be used instead of the thermosetting resin as another example. That is, when a UV curable resin is coated with a vacuum laminator and then UV-irradiated, developed, and fully cured, the UV curable resin can be formed so as to cover the desired surfaces of the separation groove 61 and the conductive pattern 51. In this case, since the next third process is performed together, the process becomes simple.
[0067]
A third step of the present invention is to remove and expose the thermosetting resin layer 50A on the surface of the desired conductive pattern 51 by laser etching, as shown in FIG.
[0068]
In this step, the thermosetting resin layer 50A is selectively removed by direct drawing and laser etching, and the conductive pattern 51 is exposed. As the laser, a carbon dioxide laser is preferable, but an excimer laser or a YAG laser can also be used. In addition, after the insulating resin is evaporated by the laser, if there is a residue at the bottom of the opening, the residue is removed by wet etching with sodium permanganate or ammonium persulfate or dry etching with an excimer laser or the like.
[0069]
In the fourth step of the present invention, a conductive film 54 is formed on the exposed conductive pattern 51 as shown in FIG.
[0070]
The conductive film 54 is used as a die pad or bonding pad by using the remaining thermosetting resin layer 50A as a mask, and depositing gold, silver or palladium by electric field or electroless plating.
[0071]
For example, a silver film adheres to a gold wire. Further, since an Au fine wire can be adhered to the silver conductive film, wire bonding is also possible. Accordingly, there is an advantage that these conductive films 54 can be used as bonding pads as they are.
[0072]
In the fifth step of the present invention, as shown in FIG. 9, the circuit element 52 is fixed on the thermosetting resinous layer 50 </ b> A of each mounting portion 65 with an insulating adhesive 58, and the circuit element 52 of each mounting portion 65 is fixed. The connection means for electrically connecting the electrode and the desired conductive pattern 51 is formed.
[0073]
The circuit element 52 is a semiconductor element such as a transistor, a diode or an IC chip, or a passive element such as a chip capacitor or a chip resistor. Although the thickness is increased, face-down semiconductor elements such as CSP and BGA can also be mounted. Further, the circuit element 52 may be a stack of a plurality of IC chips or a planar arrangement.
[0074]
Here, the bare transistor chip 52 is fixed on the thermosetting resin layer 50A with an insulating adhesive 58 such as epoxy resin, and the conductive pattern 51 is arranged around each electrode of the IC chip 52 and each mounting portion 65. The conductive coating 54 is connected through a bonding wire 55 fixed by ball bonding by thermocompression bonding or wedge bonding by ultrasonic waves.
[0075]
In this step, since a large number of conductive patterns 51 are integrated in each block 62, there is an advantage that the circuit element 52 can be fixed and wire bonded extremely efficiently.
[0076]
In the sixth step of the present invention, as shown in FIG. 10, the circuit elements 52 of each mounting portion 63 are collectively covered and insulated so as to be combined with the thermosetting resin layer 50A filled in the separation groove 61. The common molding is performed with the resin 50B.
[0077]
In this step, as shown in FIG. 10A, since the separation groove 61 and the plurality of conductive patterns 51 are already covered with the thermosetting resin layer 50A in the previous step, the insulating resin 50B covers the circuit element 52, It is combined with the thermosetting resin layer 50 </ b> A left on the surfaces of the separation groove 61 and the conductive pattern 51. In particular, if the thermosetting resin layer 50A and the insulating resin 50B are made of the same kind of thermosetting resin such as an epoxy resin, they are familiar with each other, so that stronger adhesive strength can be obtained. In order to achieve stronger adhesive strength, before molding with the insulating resin 50B, the surface of the thermosetting resin layer 50A is irradiated with UV or plasma to activate the polar groups of the resin on the surface of the thermosetting resin layer 50A. Good. Then, the thermosetting resin layer 50A and the insulating resin 50B are integrated to support the conductive pattern 51.
[0078]
Further, this step can be realized by transfer molding, injection molding, or dipping. As the resin material, a thermosetting resin such as an epoxy resin can be realized by transfer molding, and a thermoplastic resin such as polyimide resin or polyphenylene sulfide can be realized by injection molding.
[0079]
Further, when performing transfer molding or injection molding in this process, each block 62 has a mounting portion 63 placed in one common mold as shown in FIG. 10B, and one insulating resin 50 is common to each block. Mold. For this reason, compared with the method of molding each mounting part individually as in the case of a conventional transfer mold or the like, the amount of resin can be greatly reduced, and the mold can be shared.
[0080]
The thickness of the insulating resin 50 </ b> B coated on the surface of the conductive foil 60 is adjusted so that about 100 μm is coated from the top of the circuit element 52. This thickness can be increased or decreased in consideration of strength.
[0081]
The feature of this step is that the conductive foil 60 that becomes the conductive pattern 51 becomes the support substrate until the insulating resin 50B is covered. Conventionally, as shown in FIG. 16, the conductive paths 7 to 11 are formed by using the support substrate 5 that is not originally required. However, in the present invention, the conductive foil 60 serving as the support substrate is necessary as an electrode material. Material. Therefore, there is a merit that the work can be performed with the constituent materials omitted as much as possible, and the cost can be reduced.
[0082]
Further, since the separation groove 61 is formed shallower than the thickness of the conductive foil, the conductive foil 60 is not individually separated as the conductive pattern 51. Therefore, the sheet-like conductive foil 60 can be handled as a unit, and when the insulating resin 50B is molded, it has a feature that the work of transporting to the mold and mounting to the mold becomes very easy.
[0083]
Similarly, the seventh step of the present invention is to remove the conductive foil 60 in the separation groove 61 as shown in FIG.
[0084]
In this step, a resist layer 59 is attached to the back surface of the conductive foil 60 except for the portion corresponding to the separation groove 61, and chemical etching is performed with a solution of ferric chloride or the like on the conductive foil 60 using the resist layer 59 as a mask. Do. As a result, the conductive foil 60 in the separation groove 61 is selectively removed, and the bottom surface of the thermosetting resin layer 50A is exposed. Since the connection part which does not provide the separation groove 61 of the conductive foil 60 is removed, the conductive pattern 51 having the thickness of the conductive foil 60 is separated.
[0085]
As a result, the back surface of the conductive pattern 51 substantially embedded in the thermosetting resin layer 50A is exposed, and the external electrode 56 protruding about 100 μm from the back surface of the thermosetting resin layer 50A is formed as a protruding electrode. That is, it means that the external electrode 56 is formed as a protruding electrode using a connecting portion of the conductive foil 60 where the separation groove 61 is not provided.
[0086]
Further, the back surface treatment of the external electrode 56 is performed to obtain the final structure shown in FIG. That is, the external electrode 56 on which a conductive material such as solder is applied is formed on the surface, and the circuit device is completed. In this case, the conductive material such as solder goes to the side surface of the external electrode 56 and can be fixed on the conductive path of the printed circuit board and the surface and side surface of the external electrode 56, thereby increasing the fixing strength.
[0087]
Furthermore, when a thin gold plating layer 57 ′ is provided on the external electrode 56, a land grid array (LGA) structure can be realized.
[0088]
In this back surface treatment, only the external electrode 56 is exposed from the thermosetting resin layer 50A and the insulating resin 50B, so that there is an advantage that it is not necessary to use a mask and can be very easily performed.
[0089]
The eighth step of the present invention is to affix the plurality of blocks 62 to the adhesive sheet 80 with the insulating resin 50B in contact as shown in FIG.
[0090]
After etching the back surface of the conductive foil 60 in the previous step, each block 62 is separated from the conductive foil 60. Since this block 62 is connected to the remaining portion of the conductive foil 60 by the thermosetting resin layer 50A and the insulating resin 50B, it can be achieved by mechanically peeling from the remaining portion of the conductive foil 60 without using a cutting die. .
[0091]
In this process, the periphery of the pressure-sensitive adhesive sheet 80 is pasted on a stainless steel ring-shaped metal frame 81, and the central portion of the pressure-sensitive adhesive sheet 80 is provided with an interval so that the four blocks 62 do not hit the blade during dicing. The insulating resin 50B is abutted and pasted. A UV sheet (manufactured by Lintec) is used as the adhesive sheet 80, but each block 62 is an insulating resin 50B and has mechanical strength, so that even an inexpensive dicing sheet can be used.
[0092]
In the ninth step of the present invention, as shown in FIG. 13, each mounting portion of each block 62 molded together with the thermosetting resin layer 50A and the insulating resin 50B in a state of being attached to the adhesive sheet 80. The characteristic of 65 circuit elements 52 is to be measured.
[0093]
As shown in FIG. 1, external electrodes 56 are exposed on the back surface of each block 62, and the mounting portions 65 are arranged in a matrix exactly the same as when the conductive pattern 51 is formed. A probe 68 is applied to the external electrode 56 exposed from the insulating resin 50B of the conductive pattern 51, and the characteristic parameters of the circuit elements 52 of the mounting portions 65 are individually measured to determine whether the product is defective or not. Mark with magnetic ink.
[0094]
In this step, the circuit device 53 of each mounting portion 65 is integrally supported for each block 62 by the insulating resin 50B, and thus is not separately separated. Accordingly, the plurality of blocks 62 attached to the adhesive sheet 80 are vacuum-adsorbed on the tester mounting table, and the pitch is fed in the vertical and horizontal directions as indicated by the arrows for each block 62 by the size of the mounting portion 65. By doing so, the circuit device 53 of each mounting part 65 of the block 62 can be measured very quickly and in large quantities. That is, it is possible to eliminate the need for the front and back of the circuit device and the recognition of the position of the electrodes, which were necessary in the past, and to process a plurality of blocks 62 simultaneously, so that the measurement time can be greatly shortened.
[0095]
In the tenth step of the present invention, as shown in FIG. 14, the thermosetting resin layer 50 </ b> A and the insulating resin 50 </ b> B of the block 62 are separated by dicing for each mounting portion 65 while being attached to the adhesive sheet 80. There is.
[0096]
In this step, the plurality of blocks 62 attached to the pressure-sensitive adhesive sheet 80 are vacuum-sucked on the mounting table of the dicing apparatus, and the dicing blade 69 is placed on the separation groove 61 along the dicing line 70 between the mounting portions 65. The thermosetting resin layer 50 </ b> A and the insulating resin 50 </ b> B are diced and separated into individual circuit devices 53.
[0097]
In this step, the dicing blade 69 completely cuts the thermosetting resin layer 50A and the insulating resin 50B, performs dicing at a cutting depth reaching the surface of the adhesive sheet, and completely separates each mounting portion 65. At the time of dicing, the alignment mark 67 provided on the inner side of the frame-like pattern 66 around each block provided in the first step described above is recognized and dicing is performed based on this. As is well known, after dicing all dicing lines 70 in the vertical direction, the mounting table is rotated 90 degrees and dicing is performed according to the dicing lines 70 in the horizontal direction.
[0098]
In this step, the dicing line 70 has only the thermosetting resin layer 50A filled in the separation groove 61 and the insulating resin 50B bonded thereon, so that the dicing blade 69 is less worn and the metal burrs are not generated. It has the feature that it can be diced into an extremely accurate outer shape without being generated.
[0099]
Further, even after this step, even after dicing, the adhesive sheet 80 does not break apart into individual circuit devices, and the subsequent taping step can be efficiently performed. That is, the circuit device integrally supported by the pressure-sensitive adhesive sheet 80 can identify only non-defective products, and can be separated from the pressure-sensitive adhesive sheet 80 by the suction collet and stored in the storage hole of the carrier tape. For this reason, even a minute circuit device has a feature that it is not separated even once until taping.
[0100]
Although the manufacturing method of the present invention has been described in detail above, it goes without saying that the measurement can be carried out with a tester without any problem because it is integrally supported by the adhesive sheet 80 even if the measurement process and the dicing process are reversed. However, after dicing, it is sufficient to consider that the pressure-sensitive adhesive sheet 80 bends during measurement in order to support the pressure-sensitive adhesive sheet 80.
[0101]
【The invention's effect】
In the present invention, the conductive foil itself, which is the material of the conductive pattern, functions as a support substrate, and the whole is supported by the conductive foil until the separation groove is formed or the circuit element is mounted and the insulating resin is applied. When separating the foil as each conductive pattern, the insulating resin is used as a support substrate to function. Therefore, the circuit element, conductive foil, and insulating resin can be manufactured with the minimum necessary. As described in the conventional example, a support substrate is not necessary in constructing a circuit device originally, and the cost can be reduced. In addition, because the support substrate is not required, the conductive pattern is embedded in the insulating resin, and the thickness of the insulating resin and conductive foil can be adjusted, it is possible to form a very thin circuit device. There is also.
[0102]
Further, since the separation groove and the conductive pattern are covered with the thermosetting resin, there is an advantage that the thermosetting resin has a low viscosity and can increase the adhesive strength with the separation groove. Further, the bonding between the thermosetting resin and the insulating resin is easy to become familiar with each other, and both can be integrated to realize a mounting structure with higher sealing performance. Therefore, it is possible to sufficiently overcome the drawback that the thermosetting resin layer and the insulating resin from the separation groove are easily peeled off while having a single-sided mold structure of the conductive pattern. Moreover, the improvement of the adhesive strength suffices that the separation groove has a half depth of 20 to 30 μm, and an advantage that the conductive pattern can be formed into a fine pattern is obtained.
[0103]
Furthermore, since the conductive pattern is covered with the thermosetting resin layer and the conductive film, the surface can be prevented from being oxidized, and there is an advantage that the structure for realizing the oxidation prevention on the surface of the copper foil particularly when the copper foil is used.
[0104]
Furthermore, since the external electrode is formed by using the connecting portion without the separation groove of the conductive foil, the protruding electrode can be easily realized, and if it is used as a heat sink, the heat dissipation of the circuit element can be improved.
[0105]
Furthermore, since the conductive pattern can be freely routed under the circuit element, multilayer wiring cannot be achieved, but a wiring density close to multilayer wiring can be realized with a single layer.
[0106]
In the manufacturing method of the present invention, since the semi-cured thermosetting resin layer is coated immediately after the conductive pattern is formed, the separation groove can be completely filled with a liquid low-viscosity thermosetting resin, and the adhesive strength between the two is remarkably increased. There is an advantage that can be improved. Further, since the thermosetting resin layer covers the conductive pattern immediately after the formation of the conductive pattern, the surface of the conductive pattern is not oxidized by a subsequent heating step such as die bonding or wire bonding, which can contribute to improvement of reliability.
[0107]
Further, the thermosetting resin layer can be easily and selectively removed by laser etching, and the conductive film can be formed by plating using the remaining thermosetting resin layer as a mask, thereby simplifying the process.
[0108]
Furthermore, when the insulating resin is filled into the conventional separation groove by transfer molding, the insulating resin cannot be sufficiently filled into the separation groove because the viscosity of the insulating resin is high, so the adhesive strength between the separation groove and the insulating resin is There was a problem that the insulating resin could not be obtained sufficiently and peeled off from the conductive pattern. In the present invention, the adhesive strength between the separation groove and the thermosetting resin layer is solved by using a semi-cured thermosetting resin having a low viscosity, and the thermosetting resin layer and the insulating resin are familiar to each other. The adhesive strength between the conductive pattern, the thermosetting resin layer, and the insulating resin can be significantly improved.
[0109]
Furthermore, since the external electrode is formed by selectively etching away the conductive foil connecting portion of the separation groove portion, the protruding electrode can be easily realized without plating.
[0110]
Furthermore, since the conductive foil is entirely used for the conductive pattern and the external electrode except for the separation groove portion, it is possible to provide a resource-saving manufacturing method with very few parts to be discarded.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a circuit device of the present invention.
FIG. 2 is a diagram illustrating a production flow of the present invention.
FIG. 3 is a diagram illustrating a method for manufacturing a circuit device according to the present invention.
FIG. 4 is a diagram illustrating a method for manufacturing a circuit device according to the present invention.
FIG. 5 is a diagram illustrating a method for manufacturing a circuit device according to the present invention.
FIG. 6 is a diagram illustrating a method for manufacturing a circuit device according to the present invention.
FIG. 7 is a diagram illustrating a method for manufacturing a circuit device according to the present invention.
FIG. 8 is a diagram illustrating a method for manufacturing a circuit device according to the present invention.
FIG. 9 is a diagram illustrating a method for manufacturing a circuit device according to the present invention.
FIG. 10 is a diagram illustrating a method for manufacturing a circuit device according to the present invention.
FIG. 11 is a diagram illustrating a method for manufacturing a circuit device according to the present invention.
FIG. 12 is a diagram illustrating a method for manufacturing a circuit device according to the present invention.
FIG. 13 is a diagram illustrating a method for manufacturing a circuit device according to the present invention.
FIG. 14 is a diagram illustrating a method for manufacturing a circuit device according to the present invention.
FIG. 15 is a diagram illustrating a mounting structure of a conventional circuit device.
FIG. 16 is a diagram illustrating a conventional circuit device.
FIG. 17 is a diagram illustrating a conventional method for manufacturing a circuit device.
FIG. 18 is a diagram illustrating a conventional method for manufacturing a circuit device.
[Explanation of symbols]
50A thermosetting resin layer
50B insulating resin
51 Conductive pattern
52 Circuit elements
53 Circuit equipment
56 External electrode
61 Separation groove
62 blocks
80 Adhesive sheet

Claims (12)

Preparing a conductive foil and forming a conductive pattern by forming a separation groove shallower than the thickness of the conductive foil on the conductive foil excluding at least a region to be a conductive pattern;
Filling the separation groove and covering the surface of the conductive pattern with a thermosetting resin layer;
Selectively removing the portion of the thermosetting resin layer connecting the electrodes of the circuit elements on the conductive pattern;
Fixing the circuit element on the thermosetting resin layer;
Forming a connection means for electrically connecting the electrode of the circuit element and the desired conductive pattern;
Covering the circuit element, bonding with the thermosetting resin layer and molding with an insulating resin;
Removing the conductive foil left in the separation groove portion to form an external electrode protruding from the back surface of the thermosetting resin layer;
And a step of performing a back surface treatment without using a mask for the external electrode. Preparing a conductive foil and forming a conductive pattern by forming a separation groove shallower than the thickness of the conductive foil on the conductive foil excluding at least a region to be a conductive pattern;
Filling the separation groove and covering the surface of the conductive pattern with a thermosetting resin layer;
Selectively removing the portion of the thermosetting resin layer connecting the electrodes of the circuit elements on the conductive pattern;
Fixing the circuit element on the thermosetting resin layer;
Forming a connection means for electrically connecting the electrode of the circuit element and the desired conductive pattern;
Covering the circuit element, bonding with the thermosetting resin layer and molding with an insulating resin;
Removing the conductive foil left in the separation groove portion and forming an external electrode protruding from the back surface of the thermosetting resin layer,
A circuit device comprising a conductive film made of a metal material different from the conductive pattern on the desired conductive pattern exposed from the thermosetting resin layer, using the thermosetting resin layer as a mask. Manufacturing method. Preparing a conductive foil and forming a conductive pattern by forming a separation groove shallower than the thickness of the conductive foil on the conductive foil excluding at least a region to be a conductive pattern;
Filling the separation groove and covering the surface of the conductive pattern with a thermosetting resin layer;
Selectively removing the portion of the thermosetting resin layer connecting the electrodes of the circuit elements on the conductive pattern;
Fixing the circuit element on the thermosetting resin layer;
Forming a connection means for electrically connecting the electrode of the circuit element and the desired conductive pattern;
Covering the circuit element, bonding with the thermosetting resin layer and molding with an insulating resin;
Removing the conductive foil left in the separation groove portion to form an external electrode protruding from the back surface of the thermosetting resin layer;
Cutting the insulating resin and separating it into individual circuit devices,
A circuit device comprising a conductive film made of a metal material different from the conductive pattern on the desired conductive pattern exposed from the thermosetting resin layer, using the thermosetting resin layer as a mask. Manufacturing method. Preparing a conductive foil and forming a conductive pattern by forming a separation groove shallower than the thickness of the conductive foil on the conductive foil excluding at least a region to be a conductive pattern;
Filling the separation groove and covering the surface of the conductive pattern with a thermosetting resin layer;
Selectively removing the portion of the thermosetting resin layer connecting the electrodes of the plurality of circuit elements on the conductive pattern;
Fixing the plurality of circuit elements on the thermosetting resin layer;
Forming a connection means for electrically connecting the electrode of the circuit element and the desired conductive pattern;
A step of covering the plurality of circuit elements, bonding to the thermosetting resin layer and molding with an insulating resin; and removing the conductive foil left in the separation groove portion from the back side of the thermosetting resin layer Forming a protruding external electrode, and
A circuit device comprising a conductive film made of a metal material different from the conductive pattern on the desired conductive pattern exposed from the thermosetting resin layer, using the thermosetting resin layer as a mask. Manufacturing method.   The method for manufacturing a circuit device according to claim 1, wherein the conductive foil is made of any one of copper, aluminum, and iron-nickel.   5. The method of manufacturing a circuit device according to claim 1, wherein the separation groove selectively formed in the conductive foil is formed by chemical or physical etching. 6.   The circuit device manufacturing method according to claim 1, wherein a semiconductor bare chip is fixed to the circuit element.   The method for manufacturing a circuit device according to claim 1, wherein the conductive film is formed of gold, silver, or palladium plating.   The method for manufacturing a circuit device according to claim 1, wherein the connecting means is formed by wire bonding.   5. The circuit device according to claim 1, wherein the insulating resin is attached by transfer molding, and the thermosetting resin layer is bonded to the insulating resin at the time of transfer molding. Manufacturing method.   5. The method of manufacturing a circuit device according to claim 1, wherein the insulating resin is separated into individual circuit devices by dicing. 5. The method of manufacturing a circuit device according to claim 1, wherein a UV curable resin is used instead of the thermosetting resin layer .

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