JP3796765B2 - Manufacturing method of multilayer substrate for mounting electronic components - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for manufacturing a multilayer substrate for mounting electronic components, which does not require a deburring step and a lid removing step, and can simplify the thermocompression bonding operation.
[0002]
[Prior art]
As a multilayer substrate for mounting an electronic component formed by laminating a large number of insulating substrates, for example, as shown in FIG. 8, four insulating substrates 11 to 14 are laminated and pressure-bonded via prepreg adhesive layers 22 to 24. is there. Circuit patterns 5 as inner layer circuits are provided on the front side surfaces of the insulating substrates 11 to 13. Circuit patterns 51 as outer layer circuits are provided on the back side surface of the lowermost insulating substrate 11 and the front side surface of the uppermost insulating substrate 14.
[0003]
In addition, a mounting recess 10 for mounting electronic components is provided at a substantially central portion of the electronic component mounting multilayer substrate 9. The mounting recess 10 includes mounting holes 101 to 104 provided in the insulating substrates 11 to 14 and a heat radiating plate 59 joined around the mounting hole 101.
[0004]
As a method of manufacturing the multilayer board 9 for mounting electronic components, there are conventional methods, for example, shown in FIGS. The outline is shown in FIG.
First, as shown in FIG. 9, an insulating substrate 12 having a circuit pattern 5 formed on the front side surface is prepared. On the other hand, as shown in FIG. 10, a prepreg adhesive sheet 220 having the same shape as the insulating substrate 12 is prepared. Next, as shown in FIG. 11, the prepreg adhesive sheet is temporarily bonded to the back side surface of the insulating substrate 12 to form the prepreg adhesive layer 22, thereby obtaining the second unit laminate 32.
[0005]
Next, as shown in FIG. 12, a substantially central portion of the second unit laminate 32 is drilled, and a mounting hole 102 is formed in the insulating substrate 12, and an opening hole 202 is formed in the prepreg adhesive layer 22. At this time, since the so-called burrs 292 in which the fibers in the prepreg adhesive layer are exposed are generated in the opening holes 202 of the prepreg adhesive layer 22, a deburring operation is performed.
[0006]
Next, as shown in FIG. 13, the second unit laminate 32 is placed on the air plate 41, and the surface thereof is wrapped with the prepreg adhesive layer 22 and a highly releasable sealing sheet 42. The periphery of the sealing sheet 42 is stopped by a heat-resistant rubber 43 so that the inside of the sealing sheet 42 is in a vacuum state. Next, in this state, the second unit laminate 32 is baked by heating, and the prepreg adhesive layer 22 is semi-cured. Next, as shown in FIG. 14, the 2nd unit laminated body 32 is taken out from the said sealing sheet.
[0007]
Next, as shown in FIG. 15, a concave mounting hole 111 is formed in the lowermost insulating substrate 11 on which the circuit pattern 5 is formed.
Next, the said 2nd unit laminated body 32 is laminated | stacked on the front side surface of the said insulating substrate 11, these are pressed with the press board 6, a prior press is performed, and thermocompression bonding is carried out. The preceding press is performed at a lower temperature than the press described later. Thereby, an integrated two-layer substrate 302 is obtained.
[0008]
Next, as shown in FIG. 16, a third unit laminate 33 is fabricated by the same method as the second unit laminate 32. Then, the third unit laminated body 33 is laminated on the front side surface of the two-layer substrate 302, and these are pressed by the press plate 6 to perform the main pressing and thermocompression bonding. Thereby, an integrated three-layer substrate 303 is obtained.
[0009]
In addition, as shown in FIG. 17, the insulating substrate 14 provided with the prepreg adhesive layer 24 on the back side surface is produced, and a concave mounting hole 114 is formed on the back side surface to form a fourth unit laminate 34.
Next, the fourth unit laminate 34 is laminated on the front side surface of the three-layer substrate 303, and these are pressed by the press plate 6 to perform the main press and heat-press. As a result, an integrated four-layer substrate 304 is obtained.
[0010]
Next, through holes (not shown) are formed in the four-layer substrate 304, and the surface thereof is subjected to panel plating. Next, a circuit pattern as an outer layer circuit is formed on the front side surface and the back side surface of the four-layer substrate 304 by etching.
Next, the lid portions 121 and 124 of the mounting holes 111 and 114 formed in the lowermost and uppermost insulating substrates 11 and 14 are cut along the dotted lines 131 and 134 shown in FIG. The mounting holes 101 and 104 to be formed are formed.
[0011]
Thus, the electronic component mounting multilayer substrate 9 shown in FIG. 8 is obtained. Thereafter, the multi-layer substrate for mounting electronic parts is subjected to external processing, lead pins are mounted in the through holes, and the heat sink 59 is bonded.
[0012]
[Problems to be solved]
However, in the above-described conventional method for manufacturing a multilayer substrate for mounting electronic components, as shown in the flowcharts of FIGS. 8 to 17 and FIG. 1 (A), the prepreg adhesive sheet is bonded to the insulating substrate and then drilled. ing. Therefore, as shown in FIG. 12, a burr 292 is generated at the end of the opening hole 202 of the prepreg adhesive layer 22. Therefore, a deburring process is required as shown in FIG.
[0013]
In addition, as shown in FIG. 17, after all the insulating substrates 11 to 14 are stacked and thermocompression bonded, it is necessary to remove the lid portions 121 and 124 of the mounting holes 111 and 114 and open the mounting recess 10.
Furthermore, as shown in FIGS. 15 to 17, since the main pressing is performed every time the unit laminated bodies are laminated one by one, the thermocompression operation is many and the working time is long.
[0014]
In view of the conventional problems, the present invention is intended to provide a method for manufacturing a multilayer substrate for mounting electronic components, which does not require a deburring step and a lid removing step, and can simplify a thermocompression bonding operation. It is.
[0015]
[Means for solving problems]
In the present invention, the prepreg adhesive layer paired with the insulating substrate is interposed between the insulating substrates on which the circuit pattern is formed, and the insulating substrates are laminated to bring them into a vacuum state and put them in an autoclave. and to process such a laminate the prepreg adhesive layer are integrated by temporary adhesion pressurized and heated at a temperature that does not semi-cured Te,
Next, the above laminated body was taken out from the vacuum state, Ru and baked in the baking time that is tailored to a gel time of the prepreg adhesive layer is semi-cured the prepreg adhesive layer step,
Then, the manufacturing method of the multilayer board | substrate for electronic component mounting characterized by including the process of heat-pressing the said laminated body in a vacuum degree state.
[0016]
The most notable aspect of the present invention is to prepare a plurality of insulating substrates in which mounting holes and circuit patterns for forming mounting recesses are formed in advance, and a plurality of prepreg adhesive sheets in which opening holes are formed in advance. Then, all of the plurality of insulating substrates are laminated with the prepreg adhesive sheet interposed therebetween to form a laminated body that is temporarily bonded and integrated, and then the laminated body is subjected to baking and thermocompression bonding.
[0017]
The mounting holes formed in the plurality of insulating substrates are formed so as to form mounting recesses opened in at least one of the stacked bodies when the insulating substrates are stacked.
On the other hand, the hole diameter R of the opening hole in the prepreg adhesive sheet is preferably 0.05 to 0.6 mm larger than the hole diameter r of the mounting hole in the insulating substrate paired with the prepreg adhesive sheet (see FIG. 3). .
[0018]
When the difference between the hole diameter R of the opening hole and the hole diameter r of the mounting hole is less than 0.05 mm, the resin of the prepreg adhesive sheet flows into the mounting recess during the post-process thermocompression bonding. There is a fear. On the other hand, when the difference between the hole diameters exceeds 0.6 mm, the adhesion between the insulating substrate and the prepreg adhesive sheet in the vicinity of the mounting recess may be lowered. The opening hole of the prepreg adhesive sheet is formed by means of router processing, for example.
[0019]
Next, each prepreg adhesive sheet paired with the insulating substrate is interposed between the plurality of insulating substrates, and all of these are laminated and temporarily bonded to obtain an integrated laminated body.
The temporary adhesion is performed at a low temperature so that the prepreg adhesive layer made of the prepreg adhesive sheet is not semi-cured. If temporary bonding is performed at a temperature that is semi-cured or higher, it becomes difficult to adjust the cured state of the prepreg adhesive layer in the subsequent baking and thermocompression bonding.
[0020]
Next, the laminate is baked to semi-cure the prepreg adhesive layer. This baking is preferably performed at 90 to 100 ° C. Thereby, the resin flow of the prepreg adhesive layer at the time of thermocompression bonding can be suppressed, and the unevenness between the circuit patterns can be filled with the prepreg adhesive layer and flattened.
[0021]
The baking time is adjusted in accordance with the gel time of the resin of the prepreg adhesive layer. Since gel time varies depending on the type of prepreg adhesive sheet, storage conditions, and storage period, it is preferable to measure the gel time before use to determine the baking time. For example, when the gel time is 50 minutes, the baking time is 40 minutes. If the gel time is 60 minutes, the baking time is 50 minutes.
[0022]
Next, thermocompression bonding is performed on the laminate. The thermocompression bonding of the laminate is performed by, for example, a preceding press that performs thermocompression bonding while increasing the temperature, and a main press that performs thermocompression bonding at the final crimping temperature thereafter.
The thermocompression bonding is preferably performed while isotropically pressing using, for example, an autoclave. Thereby, since the pressure P is equally applied to the whole laminated body, the whole of each insulating substrate can be reliably heat-pressed (see FIG. 5).
[0023]
This thermocompression bonding is preferably performed with the laminate in a vacuum state. Thereby, it is possible to suppress problems such as outflow of resin from the prepreg adhesive layer and generation of voids in the prepreg adhesive layer at a relatively low temperature. Furthermore, in order to prevent such a problem, the vacuum condition is preferably a vacuum degree of 76 mmHg or less.
[0024]
The vacuum state of the laminated body can be realized, for example, by wrapping the laminated body with a sealing sheet, sealing the laminated body, and sucking air inside the laminated body with a vacuum exhaust device.
As the sealing sheet, polyimide, polyamide, polypropylene, polycarbonate, polymethylpentene or the like is used, and the thickness is preferably 0.03 to 2.0 mm. Thereby, heat resistance and a softness | flexibility can be provided to a sealing sheet.
[0025]
Further, it is preferable to provide a blister cloth that serves as a cushion inside the sealing sheet. The blister cloth isotropically heats and presses the entire laminate following the shape of the laminate when the laminate has a undulating shape and the recesses are very deep (for example, mounting recesses). Because. Moreover, it is for preventing the damage of the sealing sheet by the convex part of a laminated body.
As the blister cloth, glass fiber, ceramic fiber, paper, polyimide fiber, Teflon fiber or the like is used, and the thickness is preferably 0.5 to 5.0 mm.
[0026]
[Action and effect]
In the method for manufacturing a multilayer substrate for mounting electronic components according to the present invention, an opening hole is formed in advance in the prepreg adhesive sheet. Therefore, since the prepreg adhesive sheet is hollowed out independently, no burrs are generated on the processed surface. For this reason, the fiber is not exposed from the prepreg adhesive sheet, and burrs are not generated. Therefore, deburring work is unnecessary.
[0027]
Moreover, the laminated body formed by laminating the insulating substrate and the prepreg adhesive sheet has a mounting recess. For this reason, it is not necessary to perform a lid removing operation for opening the mounting recess after the thermocompression bonding.
[0028]
Further, prior to the temporary bonding, all the prepreg adhesive sheets are laminated between the plurality of insulating substrates. Therefore, the stacking process may be performed once.
Further, the subsequent temporary bonding, baking, and thermocompression bonding may be performed once, and it is not necessary to perform thermocompression bonding every time the respective layers are laminated as in the prior art (see FIG. 1). Therefore, the thermocompression bonding operation is facilitated, and a significant rationalization of the entire manufacturing process of the electronic component mounting multilayer substrate can be achieved.
[0029]
As described above, according to the present invention, it is possible to provide a method for manufacturing a multilayer substrate for mounting electronic components, which does not require a deburring step and a lid removing step, and can simplify the thermocompression bonding operation.
[0030]
【Example】
A method for manufacturing a multilayer substrate for mounting electronic components according to an embodiment of the present invention will be described with reference to FIGS.
The multilayer board 9 for mounting electronic components produced according to this example is obtained by laminating and pressing four insulating substrates 11 to 14 via prepreg adhesive layers 22 to 24. A mounting recess 10 for mounting is formed (see FIG. 8). A circuit pattern 5 is provided on the surface of each insulating substrate.
[0031]
Next, the outline of the manufacturing method of the multilayer board for mounting electronic parts will be described first.
That is, as shown in FIG. 1B, an insulating substrate (circuit creation substrate in FIG. 1) in which a mounting hole and a circuit pattern for forming a mounting recess are formed in advance, and an opening corresponding to the mounting hole. Prepare a plurality of prepreg adhesive sheets each having holes formed in advance, and laminate all of them by interposing each prepreg adhesive sheet between each of the above-mentioned insulating substrates. Then, the electronic component mounting multilayer substrate is manufactured by baking and thermocompression bonding.
[0032]
This will be described in detail below.
First, as shown in FIG. 2, the circuit pattern 5 is formed on the front side surfaces of the insulating substrates 11 to 14 made of glass epoxy. Next, through holes 101 to 104 for forming mounting recesses are formed in the insulating substrates 11 to 14 by router processing. The mounting holes 101 to 104 are designed to open wide in a stepped manner as they go upward when the insulating substrates 11 to 14 are stacked.
[0033]
Meanwhile, prepreg adhesive sheets 220, 230, and 240 that make a pair with each of the insulating substrates 12 to 14 are prepared. In this prepreg adhesive sheet, a glass cloth is impregnated with a resin. Next, opening holes 202 to 204 are formed in the prepreg adhesive sheets 220, 230, and 240 at positions corresponding to the mounting holes 102 to 104 by router processing.
[0034]
As shown in FIG. 3, the hole diameter R of the opening hole 202 is 0.2 mm larger than the hole diameter r of the mounting hole 102 of the insulating substrate 12 paired with the prepreg adhesive sheet 220. The same applies to the other opening holes 203 and 204.
[0035]
Next, as shown in FIG. 2, a resin sheet 731 (thickness: 0.1 mm) and a metal plate 741 (SUS, thickness: 1 mm) are placed on an air plate 710 provided on the platen 71 with the mylars 721 to 723 interposed. Overlapping. This is to match the length of the alignment pin. The air plate 710 is connected to a vacuum exhaust device (not shown). In this example, the above-described configuration is used, but this combination configuration is not necessary.
[0036]
Next, all of the plurality of insulating substrates are stacked and positioned on the air plate 710 with the prepreg adhesive sheets 220, 230, 240 interposed between the insulating substrates 11-14. .
[0037]
Next, the Mylar 724, the resin sheet 732, and the Mylar 725 are stacked on the uppermost insulating substrate 14 stacked. Next, these are wrapped with a blister cloth 79 and a polyamide sheet 74 as a sealing sheet, the periphery thereof is stopped with a heat-resistant rubber 75, and the air inside the polyamide sheet 74 is sucked by the vacuum exhaust device, and the degree of vacuum is 76 mm. The following.
In this state, pressure heating is performed in the autoclave, and all the insulating substrates are temporarily bonded to obtain an integrated laminate.
The temporary bonding conditions are 9 kg / cm ² and 64 ° C. as shown in FIG.
[0038]
In FIG. 2, a metal plate is overlaid on the uppermost mylar 725, and further, an insulating substrate and a prepreg adhesive sheet to be another laminated body are laminated thereon, and these are collectively collected. Thus, a plurality of sets of laminated bodies can be obtained simultaneously by temporary bonding.
[0039]
Next, as shown in FIG. 4, the laminate 7 is taken out from the sealing polyamide sheet 74. Next, the laminate 7 is baked, and the prepreg adhesive layers 22 to 24 made of the prepreg adhesive sheet are semi-cured.
[0040]
Baking is performed in a state where the laminate is leaned against a rack or the like. Baking conditions are 90-100 degreeC. The baking time is adjusted according to the gel time of the resin of the prepreg adhesive layer. For example, when the gel time is 50 minutes, baking is performed for 40 minutes, and when the gel time is 60 minutes, baking is performed for 50 minutes.
[0041]
Next, the laminate 7 is thermocompression bonded. In performing this thermocompression bonding, as shown in FIG. 5, a metal plate 83 (SUS, thickness 1 mm) and a tedlar 841 are further stacked on the air plate 82 on the platen 81, and the laminate 7 is mounted thereon. And place the tedlar 842 on top of it. These are wrapped with a blister cloth 85 and a polyamide sheet 86 as a sealing sheet, and are fixed with heat-resistant rubber 87.
Next, the inside of the polyamide sheet 86 is evacuated to a vacuum degree of 76 mmHg.
[0042]
Next, these are heated while isotropically pressurizing in an autoclave to heat-bond the laminate 7. The pressurizing medium is nitrogen gas. In this thermocompression bonding, as shown in FIG. 7, first, the preceding press is performed at 130 ° C. and 9 kg / cm ² while the temperature is increased, and then the temperature is further increased and the main press is performed at 175 ° C. and 9 kg / cm ² . .
Thus, the above-mentioned multilayer substrate for mounting electronic parts is obtained (see FIG. 8).
[0043]
Next, the function and effect of this example will be described.
In the method for manufacturing a multilayer substrate for mounting electronic components in this example, as shown in FIG. 2, opening holes 202, 203, 204 are formed in advance in the prepreg adhesive sheets 220, 230, 240. Therefore, since the prepreg adhesive sheet is hollowed out independently, no burrs are generated on the processed surface. For this reason, glass fiber is not exposed from the prepreg adhesive sheet, and burrs are not generated. Therefore, deburring work is unnecessary.
[0044]
Moreover, as shown in FIGS. 4 and 5, the laminated body 7 has a step-like mounting recess 10 that is open both vertically. Therefore, it is not necessary to remove the lid for opening the mounting recess after thermocompression bonding.
[0045]
Further, as shown in FIG. 5, prior to temporary bonding, all the prepreg adhesive sheets 220, 230, and 240 are laminated between the plurality of insulating substrates 11 to 14. Therefore, the stacking process may be performed once.
Further, the subsequent temporary bonding, baking process, and thermocompression bonding process only need to be performed once. Therefore, as shown in FIG. 1A, it is not necessary to perform thermocompression bonding every time the respective layers are stacked as in the prior art. Therefore, the thermocompression bonding operation is facilitated, and a significant rationalization of the entire manufacturing process of the electronic component mounting multilayer substrate can be achieved.
[0046]
Further, as shown in FIG. 5, during the thermocompression bonding, the entire laminated body 7 is isotropically pressurized, so that the pressure P is equally applied to the insulating substrates 11 to 14 around the mounting recess 10. . Therefore, all the insulating substrates 11 to 14 can be reliably heat-pressed and there is no adhesion failure.
[0047]
Further, the thermocompression bonding of the laminate 7 is isotropically performed in the autoclave as shown in FIG. Therefore, the pressure P is equally applied to the entire laminated body 7, and the insulating substrates 11 to 14 can be reliably adhered by the prepreg adhesive layers 22 to 24.
[0048]
In addition, as described above, since the temperature is gradually increased over the two stages of the preceding press and the main press as described above, gelation and curing of the prepreg adhesive layer can be performed separately. Precise control of the resin curing of the adhesive layer is possible.
Moreover, since the thermocompression bonding is performed under vacuum, problems such as outflow of the prepreg and generation of voids in the prepreg adhesive layer can be suppressed at a relatively low temperature.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a comparison between a method for producing a multilayer substrate for mounting electronic components according to the present invention and a conventional one.
FIG. 2 is an explanatory view showing a method for temporarily adhering a laminate according to an example.
FIG. 3 is an explanatory diagram showing the sizes of the mounting hole of the insulating substrate and the opening hole of the prepreg adhesive sheet in the example.
FIG. 4 is an explanatory diagram of a laminated body after temporary bonding in an example.
FIG. 5 is an explanatory view showing a method of thermocompression bonding in an example.
FIG. 6 is an explanatory diagram of a temporary adhesion time program in the embodiment.
FIG. 7 is an explanatory diagram of a thermocompression time program in the embodiment.
FIG. 8 is an explanatory view of a multilayer board for mounting electronic components according to a conventional example.
FIG. 9 is an explanatory diagram of an insulating substrate in a conventional example.
FIG. 10 is an explanatory diagram of a prepreg adhesive sheet in a conventional example.
FIG. 11 is an explanatory diagram of a second unit laminate in a conventional example.
FIG. 12 is an explanatory diagram of a second unit laminate in which burrs are generated in an opening hole in a conventional example.
FIG. 13 is an explanatory view showing a baking process in a conventional example.
FIG. 14 is an explanatory diagram of a second unit laminated body after baking in a conventional example.
FIG. 15 is an explanatory diagram at the time of thermocompression bonding in a two-layer lamination in a conventional example.
FIG. 16 is an explanatory view at the time of thermocompression bonding at the time of three-layer lamination, following FIG.
FIG. 17 is an explanatory view at the time of thermocompression bonding during four-layer lamination, following FIG. 16;
[Explanation of symbols]
11-14. . . Insulating substrate,
10. . . Mounting recess,
101-104. . . Mounting holes,
22-24. . . Prepreg adhesive layer,
202-204. . . Opening hole,
5. . . Circuit pattern,
7). . . Laminate,

Claims (4)

The insulating substrate is laminated between the insulating substrate on which the circuit pattern is formed, and the insulating substrate is paired with the insulating substrate, and the insulating substrate is laminated. Then, the insulating substrate is brought into a vacuum state and placed in an autoclave to bond the prepreg. and to process such a laminate layer are integrated at a temperature that will not partially cured pressurized and heated temporarily adhered to,
Next, the above laminated body was taken out from the vacuum state, Ru and baked in the baking time that is tailored to a gel time of the prepreg adhesive layer is semi-cured the prepreg adhesive layer step,
Then, the manufacturing method of the multilayer substrate for electronic component mounting characterized by including the process of heat-pressing the said laminated body in a vacuum degree state.   The method for manufacturing a multilayer substrate for mounting electronic components according to claim 1, wherein the laminated body is baked in a range of 90 to 100 ° C.   The thermocompression bonding is characterized in that the temperature is increased in two stages: a preceding press that performs thermocompression bonding while raising the temperature, and a main press that subsequently cures the prepreg layer by thermocompression bonding at the final crimping temperature. The manufacturing method of the multilayer substrate for electronic component mounting of Claim 1.   2. The method of manufacturing a multilayer substrate for mounting electronic components according to claim 1, wherein the thermocompression bonding is performed under isotropic pressure in an autoclave.

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