JP3608559B2 - Method for manufacturing element-embedded substrate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a device-embedded substrate in which a conductor pattern is formed by a transfer method using a transfer sheetAbout methodMore specifically, manufacture of device-embedded substrates that have excellent dimensional stability and can form fine-pitch conductor patternsAbout the method.
[0002]
[Prior art]
In recent years, as electronic devices such as mobile phones, PDAs (Personal Digital Assistants), and notebook personal computers have become smaller and more sophisticated, it is indispensable to support high-density mounting of electronic components constituting them. Conventionally, high-density mounting of electronic components has been supported by making finer pitches of component terminals by miniaturizing electronic components, miniaturizing conductor patterns on printed wiring boards on which electronic components are mounted, and the like.
[0003]
In recent years, multilayer printed wiring boards that enable three-dimensional wiring by stacking printed wiring boards have been developed. Development of a device-embedded substrate that incorporates electronic components such as capacitors or electrical elements such as semiconductor chips (hereinafter collectively referred to as “electrical elements”) to further improve mounting efficiency has been promoted. Yes.
[0004]
As a method for forming a conductor pattern of a printed wiring board, a transfer method using a transfer sheet is conventionally known. The printed wiring board manufacturing process using this transfer method mainly consists of a pattern formation process that forms a conductor pattern on one surface of the transfer sheet, and the transfer sheet is bonded to the insulating layer via the formed conductor pattern.AfterAnd a pattern transfer process for removing the transfer sheet.
[0005]
A printed wiring board manufactured by the transfer method can be easily multi-layered by forming vias for interlayer connection at any place of the insulating layer.
[0006]
As this type of prior art, for example, Japanese Patent No. 3051700 discloses a method for manufacturing an element-embedded substrate using a transfer method. Less than,FIG.A conventional method for manufacturing a device-embedded substrate will be described with reference to FIG.
[0007]
FIG.(A)-(F) are process sectional drawings which show the manufacturing method of the conventional element built-in board | substrate. The insulating base 31 is formed with a gap 32 for accommodating the semiconductor chip 36 and an interlayer connection via through-hole 33 configured by filling a through hole with a conductive paste (see FIG.FIG.(A)). On the other hand, a conductor pattern 35 to be transferred onto the insulating substrate 31 is formed on one surface of the transfer sheet 34 (FIG.(B)).
[0008]
Here, the insulating substrate 31 is made of a semi-cured thermosetting resin, and the transfer sheet 34 is made of a resin film such as polyethylene terephthalate (PET). In addition, the conductor pattern 35 is formed by pattern etching a conductor foil such as a copper foil previously attached to the transfer sheet 34.
[0009]
Next, the semiconductor chip 36 is bonded to a predetermined portion of the conductor pattern 35 formed on the transfer sheet 34 (FIG.(C)). Then, the upper surface of the insulating base 31 and the conductor pattern 35 side of the transfer sheet 34 are pressure-bonded to accommodate the semiconductor chip 36 in the gap portion 32 and connect the conductor pattern 35 to the via penetrating body 33 (FIG.(D)). The conductor pattern 35 is buried in the upper surface of the semi-cured insulating base 31, and then only the transfer sheet 34 is removed from the insulating base 31. Then, the element-embedded substrate 30 is completed by heat-treating the insulating base 31 and completely curing it (FIG.(E)).
[0010]
Also,FIG.As shown in (F), a multilayer wiring board 41 is obtained by laminating insulating bases 39 and 40, on which conductor patterns 37 and 38 are formed, respectively, on the element-embedded board 30 by the same method as described above.
[0011]
[Problems to be solved by the invention]
However, in this conventional method for manufacturing an element-embedded substrate, since the transfer sheet 34 is mainly composed of a resin film, the pattern of the conductor pattern 34 to be transferred due to expansion and contraction or warpage of the transfer sheet 34 that occurs during handling. There is a problem that the shape tends to be distorted. Therefore, with this conventional method for manufacturing an element-embedded substrate, it is very difficult to cope with the finer (fine pitch) conductor patterns that will be developed in the future.
[0012]
Also, is the conductor pattern 35 formed on the transfer sheet 34 formed by pattern etching a metal foil adhered on the transfer sheet 34 as disclosed in, for example, JP-A-9-270578? Alternatively, for example, as disclosed in Japanese Patent Laid-Open No. 10-335787, the metal layer formed directly on the transfer sheet 34 by a sputtering method or the like is formed by pattern etching. A wet etching method is applied as the etching method.
[0013]
That is, in the conventional method for manufacturing an element-embedded substrate, since the wet etching method is used for forming the conductor pattern 35, it is difficult to form a fine pitch pattern with high accuracy in the future. .
[0014]
On the other hand, it is also conceivable that the transfer sheet is made of a metal material such as stainless steel. In this case, since the rigidity is higher than that in the case where the transfer sheet is formed of a resin film, the dimensional stability of the conductor pattern is improved. However, in this case, if the insulating substrate that is the transfer destination is strong, it is difficult to remove the transfer sheet from the insulating substrate, and there is a problem that the transfer action of the conductor pattern cannot be performed properly.
[0015]
The present invention has been made in view of the above-mentioned problems, and can ensure the dimensional stability of the conductor pattern, form a fine-pitch conductor pattern on the insulating layer with high accuracy, and also appropriately remove the transfer sheet. Of element-embedded substrates that can be usedmethodThe issue is to provide.
[0016]
[Means for Solving the Problems]
In solving the above problems, in the present invention, the transfer sheet is made of metal, and the transfer sheet is made conductive, thereby forming a fine pitch conductor pattern with high accuracy using a pattern plating technique based on the additive method. Is possible.
When transferring the formed conductor pattern to the insulating layer, the transfer sheet and the insulating layer are bonded together, and then the transfer sheet is removed from the insulating layer. In the present invention, since the transfer sheet is mainly composed of a metal material, there is almost no dimensional change during handling, thereby ensuring the dimensional stability of the transferred conductor pattern.
[0017]
In the present invention, the transfer sheet is removed from the insulating layer mainly by dissolving and removing the transfer sheet. Thereby, even when the rigid property of the insulating layer as the transfer destination is strong, it is possible to ensure an appropriate transfer action of the conductor pattern.
[0018]
In particular, in the present invention, after forming the sealing resin layer between the conductor pattern on the insulating layer and the electric element bonded to the conductor pattern and accommodated in the gap of the insulating layer, the transfer sheet removing step It is characterized by performing. Thereby, as a result of the conductor pattern after element joining being supported by both the transfer sheet and the sealing resin layer, highly accurate formation of a fine pitch conductor pattern is ensured.
[0019]
Here, the transfer sheet can be configured to include a metal base material and a melted metal layer on which a conductor pattern is formed and which is laminated so as to be separable from the metal base material. The metal base material occupies a major part of the total thickness of the transfer sheet and is mainly configured to have mechanical or material properties required for handling. When the metal base material having such a configuration is separated and removed from the metal layer to be dissolved, the metal layer to be dissolved which is a part of the transfer sheet remains on the conductor pattern transferred onto the insulating layer. Therefore, by dissolving and removing the dissolved metal layer, the insulating layerTranscript fromRemove the sheet completely. In this case, since the time required for dissolving and removing the transfer sheet can be shortened, the transfer sheet removing process is simplified.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0021]
(First embodiment)
1 to 5 show the configuration of the element-embedded substrate 50 according to the first embodiment of the present invention. The insulating base 51 constituting the insulating layer has a gap 52 for accommodating the semiconductor chip 56 as an electric element, and through holes (through holes) 53, 53 for connecting the front and back surfaces of the insulating base 51. Is formed. The through holes 53 are filled with a conductive material 59 such as solder.
[0022]
In the present embodiment, the insulating base material 51 is composed of a resin base material mainly composed of a thermoplastic resin material, but is not limited to this, and is appropriately selected according to the application object, application, and the like. For example, a glass fiber impregnated with an epoxy resin, a glass fiber impregnated with a polyimide resin, or a paper impregnated with a phenol resin is used. Further, bismaleimide triazine resin, benzocyclobutene resin, liquid crystal polymer, and the like are also applicable.
[0023]
The lead 59 or the lead-free solder material may be used as the solder 59 filled in the through hole 53, but it is preferable to use a lead-free solder material from the viewpoint of environmental friendliness. A typical lead-free solder material is an alloy obtained by adding Bi, In, Cu, Sb or the like to a Sn—Ag system. In addition, as a conductive material other than the solder material, for example, a conductive paste in which conductive particles such as silver powder and copper powder are mixed in a resin can be used.
[0024]
Now, an adhesive material layer 54 made of a non-conductive adhesive is provided on the surface of the insulating substrate 51, and a conductor pattern 55 patterned in a predetermined shape is bonded onto the adhesive material layer 54. The conductor pattern 55 is made of, for example, an electroplated film made of copper, and is electrically connected to the semiconductor chip 56 accommodated in the gap 52 and electrically connected to the solder 59 in the through hole 53. ing. In the present invention, as will be described later, the conductor pattern 55 is formed on the insulating substrate 51 by a transfer method.
[0025]
The semiconductor chip 56 in the present embodiment is a bare chip, and gold or bumps (metal protrusion electrodes) 57 whose surfaces are plated with gold are formed on the aluminum electrode pad portion provided on the bonding surface (active surface). Has been. The bumps 57 are not limited to the ball bumps shown, but may be stud bumps or plated bumps. Further, the present invention is not limited to a semiconductor bare chip, but can be applied to a semiconductor package component or the like in which bumps are formed in rows or areas on a mounting surface such as BGA / CSP.
[0026]
In the gap 52, an underfill resin layer 58 made of a thermosetting adhesive resin such as an epoxy resin is formed between the conductor pattern 55 and the semiconductor chip 56. The semiconductor chip 56 is held in a bonded state with the conductor pattern 55 by the underfill resin layer 58. The semiconductor chip 56 in the gap 52 may be completely sealed with the same resin material.
[0027]
The surface side of the conductor pattern 55 is covered with the solder resist 60, but openings 60a and 60a are formed at portions corresponding to the through holes 53, and the conductor pattern 55 is exposed to the outside.
[0028]
According to the element-embedded substrate 50 of the present embodiment, since the conductor pattern 55 is composed of the electroplating layer, the conductor pattern 55 can be fine pitched, thereby further improving the mounting density. Can be planned.
[0029]
Next, FIG. 2 shows an element-embedded multilayer substrate 65 in which a plurality of element-embedded substrates 50 configured as described above are stacked. In this example, a configuration in which three element-embedded substrates 50 having the above-described configuration are stacked and mounted on a base substrate 66 is shown. Electrical and mechanical connection between the layers of the element-embedded multilayer substrate 65 is performed by solder 59 bonded to the surface of the conductor pattern 55 through the opening 60a of the solder resist 60.
[0030]
By connecting the layers with the solder 59 as described above, the connection can be made in a shorter time and the resistance can be reduced as compared with the case where the conductive paste is used.
[0031]
The base substrate 66 has an insulating base 67, an upper wiring layer 70 and a lower wiring layer 71 patterned on the front and back surfaces thereof, and through-hole plating 68 for connecting these wiring layers 70 and 71 to each other. Yes. The through hole is filled with a filler 69 made of a conductive material or a non-conductive material, thereby preventing the so-called popcorn phenomenon and improving the heat dissipation efficiency.
[0032]
The element-embedded multilayer substrate 65 configured as described above is in the form of a land grid array (LGA), and the lower wiring exposed to the outside through the openings 73a and 73a of the solder resist 73 when the mother substrate is mounted. External electrodes such as ball bumps are provided on the layer 71. Further, another electric element or electronic component may be mounted on the wiring layer (conductor pattern) 55 of the element-embedded substrate 50 located in the uppermost layer.
[0033]
Next, a method for manufacturing the element-embedded substrate 50 according to the present invention will be described with reference to FIGS.
[0034]
First, as shown in FIG. 3A, the insulating base 51 having the above-described configuration is prepared, and an adhesive 54 for forming an adhesive material layer is applied to the surface (FIG. 3B).
The adhesive 54 is for adhering the conductor pattern 55 to be transferred later to the insulating substrate 51 and needs to be non-conductive. Further, in order to prevent the adhesive from flowing out to the gap 52 and the through-hole 53 during the transfer of the conductor pattern 55, the material constituting the adhesive 54 is a material having a low flow property and a high shape maintaining property. An example of such a material is “AS-3000” manufactured by Hitachi Chemical Co., Ltd.
[0035]
Next, as shown in FIG. 3C, a gap forming step is performed in which a gap 52 for element accommodation and a through hole 53 for interlayer connection are formed in the insulating base 51 (step S1). For the formation of the gap 52 and the through-hole 53, for example, a known drilling technique such as machining using a drill or a router, die punching, laser machining or the like can be applied. Also good. The gap 52 needs to have an inner dimension larger than the outer shape of the semiconductor chip 56 to be accommodated.
[0036]
In parallel with the preparation process of the insulating base material 51 described above, the process of forming the conductor pattern 55 is performed as shown in FIGS. 3D to 3G (step S2). In the present embodiment, the transfer sheet 61 having the configuration shown in FIG. 5A is used to form the conductor pattern 55.
[0037]
The transfer sheet 61 includes a metal base material 62 made of copper having a thickness of, for example, about 100 μm, a conductive adhesive resin layer 63, and a melted metal layer 64 made of chromium (Cr), for example, having a thickness of 5 μm or less. It has a layered structure. The metal base material 62 and the to-be-dissolved metal layer 64 are laminated so as to be separable (peelable) from each other via the conductive adhesive resin layer 63.
[0038]
The metal base material 62 occupies a major portion of the entire thickness of the transfer sheet 61 and is mainly configured to have mechanical properties or material properties required for handling.
The conductive adhesive resin layer 63 is made of a material that can ensure electrical conduction between the metal base material 62 and the metal layer 64 to be dissolved and can be separated and removed, for example, a benzotriazole resin formed in a layer shape. Applies.
The melted metal layer 64 is composed of a metal foil or a metal plating layer, and is composed of a metal material different from the conductor pattern 55 so that it can be selectively etched with respect to the conductor pattern 55.
[0039]
Note that the configuration example for separating and removing the metal base material 62 and the melted metal layer 64 is not limited to the above, and other configuration examples can be adopted, and details thereof will be described later.
[0040]
Now, referring to FIG. 3D, a photoresist film 72 is formed on the surface of the transfer sheet 61 having the above structure on the side of the metal layer 64 to be dissolved. The photoresist 72 may be either a dry film resist or a liquid resist. Then, the formed photoresist film 72 is exposed and developed to pattern the photoresist film 72 into a predetermined shape, thereby forming a plating resist 72A (FIG. 3E).
[0041]
Subsequently, the transfer sheet 61 is immersed in a copper electrolytic bath together with the plating resist 72A, for example, and connected to a cathode electrode (not shown) to deposit a copper electroplating layer 55A on the melted metal layer 64 (FIG. 3 ( F)). Then, after the electroplating layer 55A is formed, the plating resist 72A is removed (FIG. 3G). As a result, the conductor pattern 55 made of the electroplating layer 55 </ b> A is formed on the surface of the transfer sheet 61.
The electroplating layer 55A is formed not only on the melted metal layer 64 of the transfer sheet 61 but also on the metal base material 62, but the illustration thereof is omitted.
[0042]
In general, compared to a method of removing a conductive layer by removing unnecessary portions of a conductive layer by a wet etching method (subtractive method), a method of forming a conductive pattern by depositing a conductive layer only at a necessary portion by an electroplating method (additive) According to the present embodiment, a fine pitch conductor pattern having an L / S of, for example, 10 μm / 10 μm can be formed with high accuracy.
[0043]
If a fine pitch conductor pattern is not required, a conductor layer is further formed on the melted metal layer 64 by a method such as electroplating, and the conductor layer is pattern-etched to form a conductor pattern. It is also possible to do.
[0044]
Next, as shown in FIG. 3 (H), the transfer sheet 61 and the insulating base material 51 are bonded to each other through the formed conductor pattern 55, and the conductor pattern 55 is placed on the adhesive material layer 54 on the insulating layer 51. (Step S3).
[0045]
At this time, since the transfer sheet 61 is made of metal, the strength thereof is higher than that of a transfer sheet made of a conventional resin film. Therefore, the transfer sheet 61 is prevented from expanding and contracting and warping during handling, and a fine pitch conductor. The pattern 55 can be appropriately bonded onto the insulating substrate 51 with high dimensional stability.
[0046]
In addition, since the transfer sheet 61 can have sufficient strength, pattern transfer with a higher load than before can be performed, and restrictions on the transfer process can be reduced. In particular, since local deformation of the transfer sheet is suppressed during transfer, deformation and breakage of the conductor pattern can be avoided.
[0047]
Subsequently, as shown in FIG. 4 (I), a process of accommodating the semiconductor chip 56 in the gap 52 of the insulating base 51 and bonding the bumps 57 formed on the active surface thereof to the conductor pattern 55 is performed. (Step S4). The semiconductor chip 56 is mounted on the conductor pattern 55 using, for example, a known mounter device.
[0048]
In this embodiment, since the bump 57 is made of gold or the surface thereof is plated with gold, if bonding to the conductor pattern (copper) 55 as it is, bonding between Au and Cu is performed. Therefore, if a tin (Sn) -based metal film is further formed on the surface of the conductor pattern 55 formed on the transfer sheet 61 by electroplating or the like, the bonding step becomes bonding between Au and Sn. Compared to the bonding between Au and Cu, the semiconductor chip 56 can be bonded at a low temperature and a low load. Examples of Sn-based metals include Sn and Sn-based alloys (SnAg, SnBi, SnCu, etc.). In addition to the Sn-based metal, the same effect can be obtained by forming a NiP / Au film.
[0049]
On the other hand, the bumps 57 of the semiconductor chip 56 may be formed of Sn-based metal instead of Au. In this case, bumps may be formed only with Sn-based metal, or the surface of other metal balls or resin balls may be plated with Sn-based metal. Examples of the Sn-based metal include Sn, SnAg, SnBi, SnCu, SnAgCu, SnAgBi, and SnAgBiCu.
[0050]
Now, after joining the semiconductor chip 56 to the conductor pattern 55, a thermosetting resin such as epoxy is injected into the gap 52, and an underfill resin layer 58 is formed between the conductor pattern 55 and the semiconductor chip 56. A process is performed (FIG. 4I, step S5). Thereby, the conductor pattern 55 is supported by both the transfer sheet 61 and the underfill resin layer 58.
[0051]
As described above, the “element housing” according to the present invention includes the step of bonding the semiconductor chip 56 to the conductor pattern 55 and the step of forming the underfill resin layer 58 for sealing the bonded semiconductor chip 56 inside the gap 52. Process "is configured.
[0052]
The bonding process of the semiconductor chip 56 is not limited to the above, and the semiconductor chip 56 is bonded to the conductor pattern 55 on the transfer sheet 61 in advance, and the bonded semiconductor chip 56 is bonded when the insulating base 51 and the transfer sheet 61 are bonded. May be accommodated in the gap 52. In this case, since the transfer sheet 61 is made of metal, deformation of the transfer sheet 61 due to the weight of the semiconductor chip 56 can be suppressed.
[0053]
At this time, if an adhesive is used for the plating resist 72A, for example,FIG.As shown in FIG. 5, the plating resist 72A can be used as an underfill resin layer for the semiconductor chip 56. In this case, the thickness of the conductor pattern 55 may be set to a size that the bump 57 of the semiconductor chip 56 can reach.
[0054]
Next, a step of removing the transfer sheet 61 is performed. In the present embodiment, the transfer sheet 61 is removed by separating and removing the metal base material 62 from the dissolved metal layer 64 (FIG. 4J) and dissolving and removing the dissolved metal layer 64 (FIG. 4). 4 (K)).
[0055]
Referring to FIG. 4J, the step of separating and removing the metal base material 62 from the melted metal layer 64 is performed by peeling the metal base material 62 from the melted metal layer 64 via the conductive adhesive resin layer 63. Performed (step S6).
The conductive adhesive resin layer 63 is coated with a release agent on a predetermined portion of the surface on the side of the metal layer 64 to be melted so as to be separated from the metal layer 64 to be melted together with the metal base material 62. Also good.
[0056]
The peeling process of the metal base material 62 can be easily performed by making a notch at the start of peeling at the boundary between the metal base material 62 and the melted metal layer 64 at the edge portion of the transfer sheet 61. Further, during the peeling process of the metal base material 62, the melted metal layer 64 is supported by the adhesive material layer 54 and the underfill resin layer 58 via the conductor pattern 55, and thus the metal base material 62 and the melted metal layer 64. Can be appropriately removed (FIG. 4K).
[0057]
On the other hand, in the step of dissolving and removing the metal layer 64 to be melted, only the metal layer 64 to be melted is selectively removed using an etching solution that dissolves the metal layer 64 to be melted but does not dissolve the conductor pattern 55 (FIG. 4). (L), step S7). In the present embodiment, since the conductor pattern 55 is made of copper and the metal layer 64 to be dissolved is made of chromium, for example, by using a hydrochloric acid-based etching solution, only the metal layer 64 to be dissolved is left leaving the conductor pattern 55. It can be dissolved and removed.
[0058]
As described above, the “pattern transfer process” according to the embodiment of the present invention is performed by each process from the bonding process (step S3) of the insulating substrate 51 and the transfer sheet 61 to the dissolution removal process (step S7) of the metal layer 64 to be dissolved. Is configured.
[0059]
After the removal of the transfer sheet 61 is completed, as shown in FIG. 1, a conductor filling step of filling the solder 59 as a conductive material into the through hole 53 of the insulating base 51 using a screen printing method or a dispensing method. And a step of covering the surface of the conductor pattern 55 excluding the portion corresponding to the formation site of the through hole 53 with the solder resist 60 is performed (step S8). When obtaining the element-embedded multilayer substrate 65 shown in FIG. 2, a predetermined multilayering process is performed (step S9).
[0060]
As described above, the element-embedded substrate 50 of the present embodiment is manufactured.
According to the present embodiment, since the transfer sheet 61 is made of metal, the fine pitch conductor pattern 55 can be formed with high accuracy using a pattern plating technique by electroplating. Further, since the transfer sheet 61 has predetermined mechanical strength and heat resistance, the dimensional stability of the transferred conductor pattern 55 can be ensured with almost no dimensional change during handling or heating. .
[0061]
Furthermore, the removal of the transfer sheet 61 in the pattern transfer process,After forming the underfill resin layer 58 between the conductor pattern 55 and the semiconductor chip 56,Finally, since the melting is performed by etching, an appropriate transfer action of the conductor pattern 55 can be ensured even when the insulating base 51 is rigid.
[0062]
In addition, according to the present embodiment, the transfer sheet 61 includes the metal base material 62 and the melted metal layer 64 that is detachably stacked on the metal base material 62. Since the removal is composed of a step of separating and removing the metal base material 62 from the metal layer 64 to be dissolved and a step of dissolving and removing the metal layer 64 to be dissolved, the transfer sheet 61 can be easily removed. Is improved.
0063]
(SecondEmbodiment)
FIG.andFIG.Of the present inventionSecondShows an embodiment of. In additionIn the figure, parts corresponding to those of the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.
0064]
First,FIG.As shown to (A), the insulating base material 51 is prepared and the adhesive agent for forming the adhesive material layer 54 is apply | coated to this surface (FIG.(B)).
ThenFIG.As shown in (C), a void portion forming step for forming a gap portion 52 for element accommodation and a through hole 53 for interlayer connection with respect to the insulating base 51 is performed.
0065]
In parallel with the preparation process of the insulating substrate 51,FIG.As shown in (D) to (G), the process of forming the conductor pattern 55 is performed.
In the present embodiment, the transfer sheet 61 having the configuration shown in FIG. 5A is used to form the conductor pattern 55. That is, it is comprised from the metal base material 62 which consists of copper, the to-be-dissolved metal layer 64 which consists of chromium, and the electroconductive adhesive resin layer interposed between these (FIG.9 (D)).
0066]
FIG.The conductor pattern 55 shown in (E) is composed of an electroplated layer formed on the surface of the transfer sheet 61 on the side of the metal layer 64 to be dissolved, as in the first embodiment.
In the present embodiment, thereafter, an insulating film is embedded between the formed conductor patterns, and the surface of the transfer sheet 61 on the metal layer 64 side is flattened.
0067]
This process starts withFIG.As shown in (F), an insulating film 87 made of an insulating resin such as an epoxy resin is applied to the entire surface of the transfer sheet 61 on the side of the metal layer 64 to be dissolved by, for example, a screen printing method. Apply and cure.
AndFIG.As shown in (G), the hardened insulating film 87 is polished to expose the surface of the conductor pattern 55 to the outside.
Thereby, the insulating film 87 is embedded between the conductor patterns 55, and the surface of the transfer sheet 61 on the side of the metal layer 64 to be melted is flattened.
0068]
next,FIG.As shown in (H), the transfer sheet 61 and the insulating substrate 51 are bonded to each other through the formed conductor pattern 55, and the conductor pattern 55 is bonded onto the adhesive material layer 54 on the insulating layer 51.
0069]
At this time, since the transfer sheet 91 is made of metal, the strength thereof is higher than that of a transfer sheet made of a conventional resin film. Therefore, the transfer sheet 61 is restrained from expanding and contracting and warping during handling, and a fine pitch conductor The pattern 55 can be appropriately bonded onto the insulating substrate 51 with high dimensional stability.
0070]
In addition, since the transfer sheet 61 can have sufficient strength, pattern transfer with a higher load than before can be performed, and restrictions on the transfer process can be reduced. In particular, since local deformation of the transfer sheet is suppressed during transfer, deformation and breakage of the conductor pattern can be avoided.
0071]
Further, since the surface of the transfer sheet 61 on the side of the metal layer 64 to be melted is flattened by embedding the insulating film 87 between the conductor patterns 55, the adhesive force with the adhesive material layer 54 on the insulating base material 51 is increased. Thus, the adhesive strength can be increased.
0072]
continue,FIG.As shown in (I), the process of accommodating the semiconductor chip 56 in the gap 52 of the insulating base 51 and bonding the bumps 57 formed on the active surface thereof to the conductor pattern 55 is performed.
After joining the semiconductor chip 56 to the conductor pattern 55, for example, epoxy resin is injected into the gap 52, and an underfill resin layer 58 is formed between the conductor pattern 55 and the semiconductor chip 56. Thereby, the conductor pattern 55 is supported by both the transfer sheet 61 and the underfill resin layer 58.
0073]
Since the bumps of the semiconductor chip 56 are made of gold or the surface thereof is plated with gold, Sn-based metal or Ni / Au-based metal plating is formed on the surface of the conductor pattern 55 made of copper. This makes it possible to realize chip mounting in a low temperature and low load environment.
0074]
In this case, in this embodiment, since the insulating film 87 is embedded between the conductor patterns 55, the bridge phenomenon between patterns due to isotropic growth of metal plating can be avoided.
If the region corresponding to the chip connection land on the conductor pattern 55 is soft-etched prior to the formation of the metal plating, it is effective that the flatness of the transfer surface is not impaired by the formation of the metal plating. .
0075]
Next, the transfer sheet 61 is removed. The transfer sheet 61 is removed by separating and removing the metal base material 62 from the metal layer 64 to be dissolved (FIG.(J)) and the step of dissolving and removing the to-be-dissolved metal layer 64 (FIG.(K)).
Since the transfer sheet 61 is removed by the same method as that described in the first embodiment, the description thereof is omitted here.
0076]
After removal of the transfer sheet 61 is completed,FIG.As shown in (L), the solder 59 is filled in the through hole 53 of the insulating base material 51 as a conductive material by using a screen printing method or a dispense method, and the conductor excluding the portion corresponding to the site where the through hole 53 is formed. A step of covering the surface of the pattern 55 with the solder resist 60 is performed.
0077]
As described above, the element-embedded substrate 50 'according to the present embodiment is manufactured.
According to the present embodiment, it is possible to obtain the same effect as that of the first embodiment described above.
In particular, according to the present embodiment, since the conductor pattern 55 can be adhered to the insulating base material 51 with high adhesion, an element-embedded substrate 50 ′ having excellent durability can be obtained.
Further, when metal plating is formed in the chip mount region of the conductor pattern 55, a short circuit between the patterns can be prevented, so that it is possible to cope with mounting of a semiconductor chip with a narrow pad pitch.
0078]
(ThirdEmbodiment)
continue,FIG.Of the present inventionThirdShows an embodiment of. In additionIn the figure, portions corresponding to those of the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.
0079]
In this embodiment,FIG.A plating resist 72A for electroplating formed when the conductor pattern 55 is deposited on the surface of the transfer sheet 61 shown in FIG.FIG.(B)) aboveSecondThe insulating film 87 for planarization described in the embodiment is configured.
The plating resist 72A is formed when the conductor pattern 55 is formed.FIG.As shown in (C), the space between the conductor patterns 55 is filled.
0080]
Therefore, after forming the conductor pattern 55, without separately forming an insulating film for planarization,FIG.As shown in (D), it becomes possible to bond on the insulating base material 51, therebySecondThe same effect as the embodiment can be obtained.
Moreover, if the material which has adhesiveness is used for the plating resist 72A, the conductor pattern 55 can be affixed on the insulating base material 51 with higher adhesive force.
In this case, when the wiring density of the conductor pattern 55 is relatively low, the adhesive material layer 54 on the insulating base material 51 can be omitted.
0081]
It should be noted that the chip mounting step after the conductor pattern 55 is attached (FIG.(E)) and transfer sheet removal step (FIG.(F)) is the same as that in the first embodiment described above, and a description thereof will be omitted here.
0082]
The embodiment of the present invention has been described above. Of course, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.
0083]
For example, in each of the above embodiments, the transfer sheet61 andAs shown in FIG. 5 (A), the metal base material61 andMelted metal layer64 andA metal base material with a conductive adhesive resin layer 63 interposed therebetween61 andMelted metal layer64 andThe transfer sheet is configured to be separable from each other.61'sThe configuration is not limited to this, and any configuration may be used as long as the metal base material and the metal layer to be dissolved can be separated from each other.
0084]
For example, in the transfer sheet 101 whose sectional structure is shown in FIG. 5B, an intermediate layer 103 made of chromium plating is interposed between a metal base material 102 made of copper and a melted metal layer 104 made of nickel plating. The melted metal layer (Ni) 104 and the intermediate layer (Cr) 103 are peeled off at the interface using the plating stress difference. In the step of dissolving and removing the to-be-dissolved metal layer (Ni) 104 after removing the metal base material 102 and the intermediate layer 103, when the conductor pattern to be transferred is copper, for example, a sulfated hydrogen peroxide aqueous etching solution may be used. .
0085]
5B, if the intermediate layer 103 is formed by chromium plating and the melted metal layer 104 is formed by nickel-cobalt alloy plating, the layers 103 and 104 can be easily separated at the interface. In this case, in the process of dissolving and removing the to-be-dissolved metal layer (Ni / Co) 104, when the conductor pattern to be transferred is copper, for example, a soft etching agent based on sulfated hydrogen peroxide can be applied.
0086]
In each of the above embodiments, the transfer sheet61'sRemoving the metal base material62'sStripping removal process and metal layer to be dissolved64Although the example comprised with the melt | dissolution removal process was demonstrated, instead of this, you may make it melt-remove the whole transfer sheet. In this case, the transfer sheet may be composed of a laminate of different metals as well as the same metal. Particularly in the latter case, each metal layer may be selectively etched using a different etching solution.
0087]
For example, FIG. 5C shows a configuration of the transfer sheet 111 including the first and second metal layers 112 and 114 which are different from each other. Here, when the first metal layer 112 is made of copper and the second metal layer 114 is made of nickel, only the first metal layer (Cu) 112 can be etched by using an alkali etchant. Similarly, when the first metal layer 112 is made of copper and the second metal layer 114 is made of aluminum, only the first metal layer (Cu) 112 can be etched by using sulfuric acid warm water as an etchant. Other examples of the combination of the first and second metal layers 112 and 114 include nickel and gold, copper and chromium.
0088]
Examples of combinations of these dissimilar metals include the metal layer to be dissolved(64)Composition of metal and conductor pattern(55)The present invention can also be applied as an example of a combination with other constituent metals.
0089]
Furthermore, the transfer sheet may be composed of two layers, a metal base material and a metal layer to be dissolved, and these layers may be separated by the difference in thermal expansion coefficient between the layers. Alternatively, as in the transfer sheet 121 shown in FIG. 5D, a thermal foam layer 123 is interposed between the metal base material 122 and the melted metal layer 124, and the thermal foam layer 123 is foamed by heat treatment to a predetermined temperature. Thus, the metal base material 122 and the metal layer 124 to be melted may be separated.
0090]
【The invention's effect】
As described above, the manufacture of the element-embedded substrate of the present inventionOn the wayAccording to the present invention, since a metal sheet is used for the transfer sheet, a fine pitch conductor pattern can be formed with high accuracy, and the dimensional stability of the formed conductor pattern can be secured and transferred to the insulating layer. it can. Also remove the transfer sheetAfter forming the sealing resin layer between the conductor pattern and the electric element,Since the transfer sheet is finally dissolved and removed, an appropriate transfer action of the conductor pattern can be ensured.
[0091]
Further, the transfer sheet includes a metal base material and a melted metal layer that is separably stacked on the metal base material, and the removal of the transfer sheet separates and removes the metal base material from the melted metal layer. By comprising the process and the process of dissolving and removing the metal layer to be dissolved, the time cost required for the transfer sheet removing process can be reduced, and the productivity can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a configuration of an element-embedded substrate according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a state in which the element-embedded substrate shown in FIG. 1 is multilayered.
FIGS. 3A to 3H are process cross-sectional views for explaining a method for manufacturing an element-embedded substrate according to the first embodiment of the present invention, and FIGS. , (D) to (G) show a pattern formation step, and (H) shows a part of the pattern transfer step.
FIGS. 4A to 4L are process cross-sectional views illustrating a method for manufacturing an element-embedded substrate according to the first embodiment of the present invention, wherein FIG. 4I is an element housing process, and FIGS. (L) shows the transfer sheet removal step.
FIG. 5A is a cross-sectional view schematically showing a configuration of a transfer sheet applied to the first embodiment of the present invention, and FIGS. 5B to 5D illustrate modifications thereof. It is sectional drawing.
FIG. 6 is a process flow diagram illustrating a method for manufacturing an element-embedded substrate according to the first embodiment of the invention.
[FIG.Both (A) to (H) of the present inventionSecondIt is process sectional drawing explaining the manufacturing method of the element built-in board | substrate by embodiment of this.
[FIG.Both (I) to (L) of the present inventionSecondIt is process sectional drawing explaining the manufacturing method of the element built-in board | substrate by embodiment of this.
[FIG.Both (A) to (F) of the present inventionThirdIt is process sectional drawing explaining the manufacturing method of the element built-in board | substrate by embodiment of this.
[FIG.FIG. 10 is a cross-sectional view of the main part for explaining a modification of the chip mounting process in the first embodiment of the present invention.
[Figure11(A) to (F) are process sectional views for explaining a conventional method for manufacturing a device-embedded substrate.
[Explanation of symbols]
50, 50 '... substrate with built-in element,51 ...Insulating substrate, 53 ... through hole,54 ...Adhesive material layer,5 5 ...Conductor pattern,55A ...Electroplating layer, 56 ... Semiconductor chip (electric element), 58 ... Underfill resin layer(Sealing resin layer)59 ... solder (conductive material),61 ...Transfer sheet,62 ...Metal base material, 63 ... conductive adhesive resin layer,64 ...Metal layer to be dissolved, 65... Multi-layer substrate with built-in element, 72 A... Plating resist, 80.

Claims (9)

In the method of manufacturing an element-embedded substrate in which an electrical element that is electrically joined to the conductor pattern on the insulating layer is accommodated in a gap formed in the insulating layer,
A void forming step of forming the void with respect to the insulating layer;
A pattern forming step of forming the conductor pattern on one surface of a metal transfer sheet;
A pattern transfer step of removing the transfer sheet after bonding the transfer sheet and the insulating layer to each other through the formed conductor pattern;
An element housing step of housing an electrical element bonded to the formed conductive pattern in the gap,
Removing the transfer sheet includes dissolving and removing at least a part of the transfer sheet ;
The method for manufacturing an element-embedded substrate , wherein the transfer sheet removing step is performed after forming a sealing resin layer between the conductor pattern and the electric element . The transfer sheet comprises a metal base material, and a melted metal layer that is formed so as to be separable from the metal base material while the conductor pattern is formed,
2. The element built-in according to claim 1, wherein the removal of the transfer sheet includes a step of separating and removing the metal base material from the metal layer to be dissolved and a step of dissolving and removing the metal layer to be dissolved. A method for manufacturing a substrate. The method for manufacturing an element-embedded substrate according to claim 1, wherein the pattern forming step is performed by an electroplating method. The pattern forming step includes a step of forming a conductor pattern on one surface of the transfer sheet, and a step of flattening one surface of the transfer sheet by embedding an insulating material between the formed conductor patterns. The manufacturing method of the element built-in substrate according to claim 1. The method for manufacturing an element-embedded substrate according to claim 1, wherein an adhesive is applied in advance to the upper surface of the insulating layer in the pattern transfer step. The element containing step includes: housing the electrical element in the gap and bonding the conductor pattern to the conductor pattern after the transfer sheet and the insulating layer are bonded to each other. The manufacturing method of the element-embedded substrate as described. The melted metal layer and the conductor pattern are made of different metal materials, and the step of dissolving and removing the melted metal layer uses an etching solution that dissolves the melted metal layer but does not dissolve the conductor pattern. The method for manufacturing a device-embedded substrate according to claim 2, wherein the method is performed. In the void portion forming step, a through hole for connecting the front and back surfaces of the insulating layer together with the void portion is formed,
The method for manufacturing an element-embedded substrate according to claim 1, further comprising a conductor filling step of filling the through hole with a conductive material. 9. The device-embedded substrate manufacturing method according to claim 8 , further comprising a stacking step of stacking the manufactured device-embedded substrate in multiple layers with electrical connection in the through hole after the conductor filling step. Method.

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