CN113179580A - Metal-based FR4 mixed-compression substrate and production method thereof - Google Patents

Abstract

The invention discloses a metal-based FR4 co-laminated substrate and a production method thereof, wherein the metal-based FR4 co-laminated substrate comprises a metal base layer, a bonding layer, an FR4 base material layer and a circuit layer which are sequentially stacked from bottom to top, one end of the metal base layer extends outwards to form the FR4 base material layer, and one ends of the FR4 base material layer and the circuit layer extend outwards to form the bonding layer, so that the upper and lower overlapped areas of the FR4 base material layer and the metal base layer are bonded together through the bonding layer. According to the invention, the metal base and the FR4 substrate are only overlapped in a partial area, so that a staggered step metal substrate is formed between the metal base and the FR4 substrate, and the metal base and the FR4 substrate are special in structure and suitable for a position space specially designed for special equipment.

Description

Metal-based FR4 mixed-compression substrate and production method thereof

Technical Field

The invention relates to the technical field of printed circuit board manufacturing, in particular to a metal-based FR4 mixed-compression substrate and a production method thereof.

Background

At present, with the development of the electronic industry, electronic products with high power and large current are more and more widely applied, and the requirements on circuit boards serving as electronic component carrier plates are also more and more high.

In the current industry, metal substrates are generally formed by laminating FR4 and metal bases in equal areas, the whole substrate is uniform in equal thickness, the positions and spaces for placing PCB substrates are special for some specially designed equipment, and common substrates with the same thickness cannot be placed.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, the present invention provides a FR4 hybrid metal-based substrate, which has a special structure and is suitable for a position space specially designed for a special device, wherein a stepped metal substrate is formed between the FR4 substrate and the metal-based substrate by a structure of only an overlapping region.

In order to solve the technical problem, the invention provides a metal-based FR4 co-laminated substrate which comprises a metal base layer, a bonding layer, an FR4 base material layer and a circuit layer which are sequentially stacked from bottom to top, wherein one end of the metal base layer extends out of the FR4 base material layer, and one ends of the FR4 base material layer and the circuit layer extend out of the bonding layer, so that the upper and lower overlapped regions of the FR4 base material layer and the metal base layer are bonded together through the bonding layer.

Furthermore, the metal base layer is provided with a groove at a position corresponding to the bonding layer.

Further, the depth of the groove is 15-25 μm.

Further, metal base FR4 mixed pressing base plate still includes from top to bottom runs through the through-hole of circuit layer, FR4 substrate layer, tie coat and metal basic unit in proper order.

Further, the metal-based FR4 hybrid board further includes a solder mask layer disposed on the circuit layer.

Further, the metal matrix is copper-based or aluminum-based.

Further, the bonding sheet is a no-flow glue PP sheet.

The invention also provides a production method of the metal-based FR4 mixed-compression substrate, which comprises the following steps:

s1, cutting metal bases with the same length and width specification, non-flowing glue PP sheets and FR4 base plates;

s2, depth control is carried out on the region, overlapped with the FR4 substrate, of the later period of the metal base to form a groove, then a slotted hole is formed in the metal base on one side of the groove, and the edge of one side of the slotted hole is overlapped with the edge of one side of the groove;

s3, manufacturing a circuit on one surface of the FR4 substrate through a negative film process, completely etching a copper layer on the other surface, and then sequentially manufacturing a solder mask layer and performing surface treatment on the FR4 substrate;

s4, windowing is respectively carried out at the corresponding positions of the FR4 substrate and the no-flow PP sheet;

s5, pressing the metal substrate and the FR4 substrate together through a non-flowing glue PP sheet to form a production board; wherein, the FR4 substrate corresponds to the non-flowing PP sheet up and down;

s6, drilling through holes on the production board;

s7, cutting the inner-layer no-flow PP sheet at the edge of the groove through a slotted hole in the metal base to expose the FR4 base material layer of the inner layer;

s8, removing the parts except the windowing and the slotted holes on the production plate through molding;

and S9, finally removing the residual non-flowing glue PP sheet at the position of the slotted hole on the production board to obtain the metal-based FR4 mixed-pressing base board.

Further, the following steps are included between steps S1 and S2:

s11, respectively drilling first riveting holes at the positions corresponding to the plate edges of the FR4 substrate, the metal substrate and the no-flow-glue PP sheet, and drilling second riveting holes with the hole diameter smaller than that of the through holes at the positions corresponding to the through holes at the later stage of drilling of the three.

Further, in step S5, before pressing, a rivet is inserted through the riveting hole to rivet and fix the metal base, the no-flow PP sheet, and the FR4 base plate together, wherein the metal rivet is used to rivet in the first riveting hole, and the bamboo/wood pin is used to rivet in the second riveting hole.

Further, in step S2, a groove with a depth of 15-25 μm is deeply milled by the milling machine.

Further, in step S4, the window on the no-flow PP sheet is 0.1mm larger than the window on the FR4 substrate.

Further, in step S7, the inner layer no-flow PP sheet is cut by laser or a blade.

Further, in step S9, the residual no-flow PP sheet is removed by direct peeling and blade cutting.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, through the structure that the metal base and the FR4 substrate are only overlapped in a partial area, a stepped metal substrate with staggered arrangement and uniform thickness and non-uniformity is formed between the metal base and the FR4 substrate, and the stepped metal substrate is special in structure and is suitable for a position space specially designed for special equipment; in addition, the groove arranged on the metal base layer can coarsen the groove area, and the binding force between the metal base layer and the binding layer is improved.

The invention also provides a specific production method, the metal-based FR4 mixed-pressing substrate has a special structure and high manufacturing difficulty, the method provides the whole manufacturing process, and the qualified metal-based FR4 mixed-pressing substrate can be effectively and efficiently manufactured; the method comprises the steps of firstly roughening the surface of the metal base in a groove routing mode, wherein compared with a local chemical roughening (needing to sequentially carry out film sticking, micro-etching and film removing) or local physical roughening (roughening through a grinding plate) mode in the prior art, the groove routing roughening mode can reduce the chemical roughening procedure to improve the production efficiency, and can avoid the quality problem of metal base bending in the local physical roughening process and improve the production quality; in addition, the non-flowing glue PP sheet is adopted for pressing, the window opening and the slotted hole of the flowing glue are reduced, the non-flowing glue PP sheets at the metal base platform and the FR4 platform are convenient to remove at the later stage, the window opening of the non-flowing glue PP sheets is larger than the window opening of the FR4 substrate, the flowing glue on the non-flowing glue PP sheets is prevented from overflowing to the outer side surface of the FR4 substrate in the pressing process, and the circuit layer on the FR4 substrate is ensured not to be polluted by the flowing glue; and drilling a second riveting hole with the aperture smaller than that of the through hole at the position corresponding to the later-stage through hole drilling position in the FR4 substrate, the metal base and the no-flow glue PP sheet, and riveting the riveting hole by using a bamboo/wood pin in the later-stage riveting process, so that the bamboo/wood pin can be removed simultaneously in the later-stage through hole drilling process, the metal pin is prevented from being removed before drilling by using a metal pin mode, the quality of the board is easily influenced in the metal pin removing process, for example, the board surface circuit is scratched, and the like, and the production efficiency and the production quality are effectively improved by the method.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

FIG. 1 is a schematic view of a metal-based FR4 co-extruded substrate of example 1;

fig. 2 is a schematic flow chart of manufacturing a metal-based FR4 hybrid substrate in example 2.

Detailed Description

For a fuller understanding of the technical aspects of the present invention, reference should be made to the following detailed description taken together with the accompanying drawings; it should be noted that, if "first" or "second" is described in the text, it is used to distinguish different components, and the like, and does not represent the order of precedence, and does not limit "first" and "second" to be different types.

It is to be understood that the embodiments described below are only a few embodiments of the present invention, and not all embodiments; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

As shown in fig. 1, the metal-based FR4 co-laminated substrate shown in this embodiment includes a metal base layer 1, a bonding layer 2, an FR4 substrate layer 3, and a circuit layer 4 that are sequentially stacked from bottom to top, where one end of the metal base layer 1 extends outward to form an FR4 substrate layer 3, and forms a metal-based platform 10, one ends of the FR4 substrate layer 3 and the circuit layer 4 extend outward to form the bonding layer 2 and the metal base layer 1, and form an FR4 platform 31, and the directions of the outward extension of the metal base layer and the FR4 substrate layer are different, so that the FR4 substrate layer 3 and the metal base layer 1 are overlapped only in a partial region, and the upper and lower overlapped regions of the two are bonded together through the bonding layer 2; in the above, the metal base and the FR4 substrate are arranged so as to overlap only in the partial region, and a stepped metal substrate having a nonuniform uniform thickness is formed between the two.

Specifically, metal substrate 1 is equipped with recess 11 in the position department that corresponds tie coat 2, can make this recess region realize the alligatoring through the recess that sets up on metal substrate, has improved the cohesion between metal substrate and the tie coat.

Specifically, the depth of the groove 11 is 15-25 μm, and the bonding area is coarsened while the influence of the excessive depth of the groove on the later-stage glue filling quality is avoided.

In this embodiment, this metal base FR4 thoughtlessly presses base plate still includes from top to bottom and runs through circuit layer 4, FR4 substrate layer 3, tie coat 2 and metal basic unit 1's through-hole 6 in proper order, and this through-hole is mounting hole or fixed orifices for fix this metal base FR4 thoughtlessly presses base plate on corresponding machine equipment.

Specifically, the metal-based FR4 hybrid board further includes a solder mask layer 5 disposed on the circuit layer 4 for protecting the circuit layer.

In other embodiments, the metal matrix is copper-based or aluminum-based.

In other embodiments, the bonding sheet is a no-flow PP sheet.

In other embodiments, the solder mask layer covers only a portion of the circuit layer, and the other uncovered circuit layers are plated with the nickel layer to prevent the circuit layer from being oxidized.

Example 2

As shown in fig. 2, the method for producing a metal-based FR4 hybrid substrate according to this embodiment is used to produce the metal-based FR4 hybrid substrate according to embodiment 1, and sequentially includes the following processing steps:

(1) cutting: the metal substrate, the FR4 substrate and the PP sheet are cut according to the size of a jointed board of 520mm multiplied by 620mm, the thickness of the FR4 substrate is 0.5mm (excluding the thickness of the outer copper layer), and the thickness of the copper layers on two sides of the FR4 substrate is 0.5oz or 1 oz.

(2) Drilling: first riveting holes are respectively drilled at the positions corresponding to the plate edges of the FR4 substrate, the metal substrate and the no-flow-glue PP sheet, and second riveting holes with the hole diameter smaller than that of the through holes are drilled at the positions corresponding to the through holes drilled at the later stage among the first riveting holes, the second riveting holes and the no-flow-glue PP sheet.

(3) Routing and grooving of a metal base: and a groove with the depth of 15-25 microns is deeply milled in the overlapped area of the FR4 substrate at the later stage of the metal substrate through a milling machine, a slotted hole is formed in the metal substrate at one side of the groove, the position of the slotted hole corresponds to the FR4 platform formed by outwards extending and exposing the FR4 substrate at the later stage, and one side edge of the slotted hole is overlapped with one side edge of the groove, namely the slotted hole is close to the groove.

(4) Manufacturing a circuit (negative film process): coating a photosensitive film on an FR4 substrate by a vertical coating machine, controlling the film thickness of the photosensitive film to be 8 μm, completing circuit exposure on one surface of the FR4 substrate by a 5-6 grid exposure ruler (21 grid exposure ruler) by adopting a full-automatic exposure machine, not exposing the other surface of the FR4 substrate, and forming a circuit pattern after development; and etching the inner layer, namely etching a circuit on one surface of the exposed and developed FR4 substrate, etching all the same side of the other surface to expose the FR4 base material layer, and then stripping the film.

(5) And manufacturing a solder mask layer and silk-screen characters: spraying solder resist ink on the surface of a circuit layer of an FR4 substrate except a solder resist windowing position, sequentially carrying out pre-curing, exposure, development and thermosetting treatment to solidify the solder resist ink into a solder resist layer, and adopting spraying printing of TOP surface solder resist ink, wherein the TOP surface characters are added with a UL mark, so that a protective layer which prevents bridging between circuits during welding, provides a permanent electrical environment and resists chemical corrosion is coated on the circuits and the base materials which do not need to be welded, and the protective layer plays a role in beautifying the appearance

(6) Surface treatment (nickel-gold deposition): the copper surface of the welding pad at the solder stop windowing position is communicated with a chemical principle, a nickel layer and a gold layer with certain required thickness are uniformly deposited, and the thickness of the nickel layer is as follows: 3-5 μm; the thickness of the gold layer is as follows: 0.05-0.1 μm.

(7) Windowing: windowing is respectively carried out at corresponding positions of the FR4 substrate and the no-flow PP sheet, and the windowing positions correspond to metal base platforms formed by outward extending and exposing of the metal bases at the later stage; the window on the no-flow PP sheet is 0.1mm larger than the window on the FR4 substrate, so that the flow glue on the no-flow PP sheet is prevented from overflowing to the outer side surface of the FR4 substrate in the pressing process, and the circuit layer on the FR4 substrate is prevented from being polluted by the flow glue.

(8) And (3) laminating: the method comprises the following steps of firstly carrying out blackening or browning treatment on a metal base and an FR4 base plate, wherein the browning speed is browned according to the thickness of copper at the bottom, and laminating the FR4 base plate and the metal base in sequence according to requirements by using a no-flow adhesive PP sheet (the specific laminating sequence is that the FR4 base plate, the no-flow adhesive PP sheet and the metal base) to form a production plate, wherein windows on the FR4 base plate and the no-flow adhesive PP sheet are vertically corresponding; and before the pressing, a rivet penetrates through the riveting hole to rivet and fix the three together, so that the deviation problem is avoided, wherein the first riveting hole is riveted by a metal rivet, and the second riveting hole is riveted by a bamboo/wood pin, so that the bamboo/wood pin can be removed simultaneously in the later through hole drilling process, the metal pin needs to be removed before the drilling by adopting a metal pin mode, the quality of the board is easily influenced in the metal pin removing process, for example, the board surface circuit is scratched, and the like, so that the production efficiency and the production quality are effectively improved.

(9) Drilling: the production plate is subjected to blackening or browning removing treatment to remove a browning layer or a blackening layer on the production plate, then drilling is carried out by using drilling data, so that a through hole is coaxially drilled at a second riveting hole on the production plate, and the bamboo/wood pin in the second riveting hole is removed while the through hole is drilled.

(10) Cutting: the non-flowing glue PP sheet of the inner layer is cut at the edge of the groove through the slotted hole in the metal base, so that the non-flowing glue PP sheet is disconnected and the FR4 base material layer of the inner layer is exposed, and laser or blade cutting is adopted during cutting.

(11) And electrical test: testing the electrical conduction performance of the finished board, wherein the board use testing method comprises the following steps: and (5) flying probe testing.

(12) And forming: according to the prior art and according to the design requirement, the shape is milled, the tolerance of the shape is +/-0.05mm, and the parts except the windowing part and the slotted hole on the production plate are removed through forming so as to expose the metal base platform at the windowing part.

(13) And removing glue: and finally, removing the residual non-flowing glue PP sheet at the position of the slotted hole on the production board in a mode of directly stripping and cutting by a blade to expose the FR4 platform, and preparing the uniform-thickness non-uniform metal-based FR4 mixed-pressing base board.

(14) FQC: and (4) inspecting the appearance of the finished board according to the customer acceptance standard and the inspection standard of my department, and timely repairing the finished board if a defect exists so as to ensure that excellent quality control is provided for the customer.

(15) FQA: and measuring whether the appearance, the hole copper thickness, the dielectric layer thickness, the green oil thickness, the inner layer copper thickness and the like of the finished board meet the requirements of customers or not.

(16) And packaging: and hermetically packaging the finished boards according to the packaging mode and the packaging quantity required by the customer, putting a drying agent and a humidity card, and then delivering.

In other embodiments, the metal matrix is copper-based or aluminum-based.

The technical solutions provided by the embodiments of the present invention are described in detail above, and the principles and embodiments of the present invention are explained herein by using specific examples, and the descriptions of the embodiments are only used to help understanding the principles of the embodiments of the present invention; meanwhile, for a person skilled in the art, according to the embodiments of the present invention, there may be variations in the specific implementation manners and application ranges, and in summary, the content of the present description should not be construed as a limitation to the present invention.

Claims (10)

1. The utility model provides a metal base FR4 thoughtlessly presses base plate, its characterized in that includes metal-based layer, tie coat, FR4 substrate layer and the circuit layer that stacks gradually the setting from bottom to top, the one end of metal-based layer outwards extends FR4 substrate layer, the one end on FR4 substrate layer and circuit layer outwards extends the tie coat, so that the upper and lower overlapping area of FR4 substrate layer and metal-based layer passes through the tie coat bonds together.

2. The metal-based FR4 hybrid substrate according to claim 1, wherein the metal-based layer is provided with a groove at a position corresponding to the bonding layer.

3. The metal-based FR4 hybrid substrate of claim 2, wherein the depth of said groove is 15-25 μm.

4. The metal-based FR4 composite substrate of claim 3, further comprising a through hole passing through the circuit layer, the FR4 substrate layer, the adhesive layer and the metal base layer from top to bottom.

5. The metal-based FR4 hybrid substrate of claim 4, further comprising a solder mask layer disposed on said circuit layer.

6. A production method of a metal-based FR4 co-extruded substrate is characterized by comprising the following steps:

s1, cutting metal bases with the same length and width specification, non-flowing glue PP sheets and FR4 base plates;

s2, depth control is carried out on the region, overlapped with the FR4 substrate, of the later period of the metal base to form a groove, then a slotted hole is formed in the metal base on one side of the groove, and the edge of one side of the slotted hole is overlapped with the edge of one side of the groove;

s3, manufacturing a circuit on one surface of the FR4 substrate through a negative film process, completely etching a copper layer on the other surface, and then sequentially manufacturing a solder mask layer and performing surface treatment on the FR4 substrate;

s4, windowing is respectively carried out at the corresponding positions of the FR4 substrate and the no-flow PP sheet;

s5, pressing the metal substrate and the FR4 substrate together through a non-flowing glue PP sheet to form a production board; wherein, the FR4 substrate corresponds to the non-flowing PP sheet up and down;

s6, drilling through holes on the production board;

s7, cutting the inner-layer no-flow PP sheet at the edge of the groove through a slotted hole in the metal base to expose the FR4 base material layer of the inner layer;

s8, removing the parts except the windowing and the slotted holes on the production plate through molding;

and S9, finally removing the residual non-flowing glue PP sheet at the position of the slotted hole on the production board to obtain the metal-based FR4 mixed-pressing base board.

7. The method for producing metal-based FR4 co-pressed substrate according to claim 6, wherein the steps between S1 and S2 further comprise the steps of:

s11, respectively drilling first riveting holes at the positions corresponding to the plate edges of the FR4 substrate, the metal substrate and the no-flow-glue PP sheet, and drilling second riveting holes with the hole diameter smaller than that of the through holes at the positions corresponding to the through holes at the later stage of drilling of the three.

8. The method for producing a metal-based FR4 hybrid substrate of claim 7, wherein in step S5, the metal-based, no-flow PP sheet and FR4 substrate are riveted together by rivets which are inserted through riveting holes before pressing, wherein the metal rivets are riveted in the first riveting holes and the bamboo/wood pins are riveted in the second riveting holes.

9. The method for producing the metal-based FR4 hybrid board according to claim 6, wherein in step S2, a groove with a depth of 15-25 μm is mechanically deep milled by a milling machine.

10. The method for producing a metal-based FR4 hybrid substrate as claimed in claim 6, wherein in step S4, the window of the no-flow PP sheet is 0.1mm larger than the window of the FR4 substrate.

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