KR20170098239A - Hole plug for thin laminate - Google Patents

Abstract

A method for forming a hole plug in a laminate structure is provided. A laminate structure is formed that includes at least a dielectric layer and a first conductive foil on a first side of the dielectric layer. A non-perforated or blind hole is formed in the laminate structure that extends from the second side of the dielectric layer at least partially through the dielectric layer and toward the first conductive foil, the hole having a hole depth to hole diameter aspect ratio of less than 10 to 1. In yet another example, the hole aspect ratio may be less than one to one. The via fill ink can then be deposited in the hole. The via fill ink is then dried and / or cured to form a hole plug.

Description

[0001] HOLE PLUG FOR THIN LAMINATE FOR THIN LAMINATE [0002]

This application claims priority to U.S. Provisional Application No. 62/096011, filed December 23, 2014, and U.S. Provisional Application No. 62/096817, filed December 24,

Various features relate to laminate structures, and more particularly to methods of forming hole plugs in thin laminate structures.

Laminate structures such as printed circuit boards are typically fabricated by first depositing sub-composite structures and / or other sub-composite structures with additional external sheets / layers. One or more holes are formed in the sub-composite (e. G., Drilling) for via holes. If the laminations are thinner and the diameters of the holes are larger, it becomes inappropriate to use conventional hole filling materials and processes.

As a result, there is a need for a way to create hole plugs in thin, laminate structures in an efficient and cost-effective manner.

The first aspect provides a method of forming a hole plug in a laminate structure. A laminate structure is formed that includes at least a dielectric layer and a first conductive foil on a first side of the dielectric layer. A non-perforated or blind hole is formed in the laminate structure that extends from the second side of the dielectric layer at least partially through the dielectric layer to the first conductive foil and the holes have a hole depth to hole diameter aspect ratio of 10 to 1. In another example, the hole aspect ratio (e.g., hole depth to hole diameter ratio) is less than three to one. In yet another example, the hole aspect ratio may be less than one to one. The via fill ink can then be deposited in the hole. The via fill ink is then dried and / or cured to form a hole plug.

The laminate structure may further comprise a second conductive foil on the second side of the dielectric layer, wherein the second conductive foil is penetrated by the holes. Additionally, the laminate structure may further comprise a disposable layer on the second conductive foil.

The multilayer printed circuit board may then be formed of a laminate structure.

Additionally, plated through holes may be formed through the hole plug material. The hole may be formed with a drill having a point angle of 125 degrees or more.

In one case, the hole may be formed with a drill having a point angle of greater than 155 degrees. That is, the hole may have a lower portion with a corner having a point angle of greater than 155 degrees. In this way, the drill can be configured to form a bottomed corner trimmed in the hole. The bottom of the hole may be flat (i.e. not a point) between the trimmed bottom corners.

In some instances, the via fill ink may be deposited by at least one of: (a) screen printing, (b) stencil printing, or (c) holoscoping the via fill ink. In some cases, non-peel ink deposition can be assisted by vacuum. In yet other cases , the via fill ink may be debubbled in the vacuum chamber (e.g., before curing).

In some cases, the via fill ink may be dried and / or cured in an oven. In some embodiments, vacuum drying and heat curing treatments may be performed simultaneously to cure the non-fill ink.

In some embodiments, the first conductive foil may have a thickness of less than 12 ounces, less than 2 ounces, or less than 1 ounce. In other embodiments, the dielectric layer may have a thickness of less than 20 mils, less than 16 mils, or less than 12 mils.

The hole plug can be made of a plating resist or material that prevents metal plating.

The second aspect provides a laminate structure having a hole plug. The laminate structure may include at least a dielectric layer and a first conductive foil on a first side of the dielectric layer. The non-perforated or blind holes in the laminate structure may extend from the second side of the dielectric layer toward the first conductive foil and the holes have a hole depth to hole diameter aspect ratio of less than 10 to 1. The via fill ink may be deposited in the hole to form a hole plug. The laminate may further comprise a second conductive foil, wherein the second conductive foil is penetrated by the holes. The plurality of conductive and dielectric layers are bonded to the laminate structure to form a multilayer printed circuit board.

Additionally, the laminate structure may include plated through holes through the hole plug material. In various examples, the hole aspect ratio may be less than 3 to 1, or less than 1 to 1. The holes may have a trimmed bottom corner. In one example, the trimmed bottom corner of the via hole may have a point angle of greater than 125 degrees. In another example, the trimmed bottom corner of the via hole may have a point angle of greater than 155 degrees.

In some cases, the first conductive foil may have a thickness of 12 ounces or less, 2 ounces or less, or 3 microns or less. In other instances, the dielectric layer may have a thickness of 20 mils or less, 16 mils or less, or 12 mils or less.

The hole plug may be a plating resist or material that prevents metal plating.

The third aspect provides a method for forming a hole plug in a laminate structure. A laminate structure including a dielectric layer, a first conductive foil on a first side of the dielectric layer, and a second conductive foil on a second side of the dielectric layer. The second conductive foil may be masked and etched to form holes that expose portions of the dielectric layer on the second conductive foil. Laser drilling may be performed through the exposed portion of the laminate structure to form a non-penetrating or blind hole that extends through at least partially through the dielectric layer and faces the first conductive foil, wherein the hole has a hole depth of less than 10 to 1 And a large hole diameter aspect ratio. The via fill ink is deposited and cured in the hole to form a hole plug. The second conductive foil may be penetrated by the hole.

The laminate structure may comprise a disposable layer on the second conductive foil.

Figure 1 illustrates a cross-sectional view of the configuration of a non-penetrating laminate structure having filled via holes.
Figure 2 is a flow chart illustrating a method of forming a non-perforated thin laminate structure having a hole plug.
Figure 3 illustrates a cross-sectional view of the construction of a non-penetrating laminate structure having laser-drilled filled via holes.
Figure 4 is a flow chart illustrating a method of forming a thin laminate structure having a hole plug.
Figure 5 illustrates an exemplary drill that may be used for the holes according to Figures 1 and 2.

In the following description, specific details are given to provide a thorough understanding of various aspects of the disclosure. However, it will be understood by those skilled in the art that aspects may be practiced without these specific details. For example, circuits may be shown in block diagrams to avoid obscuring aspects with unnecessary detail. In other instances, well-known circuits, structures, and techniques may not be shown in detail in order not to obscure aspects of the present disclosure.

The word "exemplary" is used herein to mean serving as an example, instance, or illustration. Any embodiment or aspect described herein as "exemplary " is not necessarily to be construed as preferred or advantageous over other aspects of the disclosure. Furthermore, the term "aspects" does not require all aspects of the present disclosure to include the discussed features, advantages or modes of operation.

Charged Via  Exemplary with holes Non-perforated  Thin laminate structure

1 illustrates a cross-sectional view of the configuration of a unpierced laminate structure 100 having filled via holes. In step 1 (step A), the laminate structure 100 includes a first conductive layer or foil 106 (e.g., a copper foil) and / or a dielectric layer sandwiched between the second conductive layer or foil 104 102). ≪ / RTI > Although a double-sided laminate 100 is illustrated, cross-sectional laminates (i.e., one dielectric layer and one conductive layer or foil) and / or an unclad laminate are also contemplated for use. In one example, the first conductive layer or foil 106 and the second conductive layer or foil 104 are formed using a conventionally available copper foil thickness, for example, approximately 12 oz (approximately 420 microns) Thickness) and 3 microns or less in thickness. In one example, the dielectric layer 102 may have a thickness of 20 mils or less.

In the second step (step B), the drill 108 may be used to form the non-penetrating or blind hole 110 through the second conductive layer or foil 104 and the dielectric layer 102, But does not penetrate or penetrate the conductive layer or foil 106 and only partially drill. The drill point angle may be greater than 125 degrees to create a non-penetrating or blind hole (110) through at least the second conductive layer or foil (104) without penetrating the first conductive layer or foil (106). Alternatively, the drilling machine used may have a depth sensor from the surface or drill depth of the laminate structure 100. In yet another embodiment, the drill machine may have sensors to sense when the drill contacts the first and / or second conductive layer or foil.

In the third step (step C), the hole 110 is formed in the non-penetrating laminate structure 100. The aspect ratio of the hole depth to the hole diameter is preferably 10: 1 or less, 5: 1 or less, 4: 1 or less, 3: 1 or less, 2: 1 or less, 1: 2 or less, 1: 3 or less, or 1:10 or less. For example, if the hole depth is 100 microns deep and the hole diameter is 1 millimeter wide, then the aspect ratio (i.e., hole depth to hole diameter ratio) may be 1:10 or 0.1. Conventional via fill ink and hole filler machines are designed to target through holes having aspect ratios of 5: 1 or greater.

In the fourth step (step D), the via fill ink 112 (or other similar via fill material of similar viscosity) is deposited into the hole 110 using a hole filler machine. In one example, the hole filler machine may feature a vacuum assisted process to prevent bubbles in the non-fill ink. Once inserted into the hole 110, the via fill ink 112 may form a hole plug. In one example, the via fill ink 112 may be a plating resist material. According to various approaches, via-fill ink 112 may be deposited by screen or stencil printing, by ink dispenser, by squeegeeing on the surface, and these processes may be assisted by vacuum. In some embodiments, the vias formed on the surface of the laminate substrate 100 may be made of a disposable layer so that after the non-peel ink is deposited in the hole 110, the disposable layer is removed from the surface of the laminate structure 100 Lt; / RTI >

1: 1 or less, 1: 2 or less, or 1: 2 or less) of the hole depth to the hole diameter (for example, 10: 1 or less, 5: 1 or less, : Aspect ratio of 10 or less), conventional via fill materials and / or processes do not work well. It should be appreciated that conventional via fill materials can not adequately fill holes 110 and conventional filler machines can be responsible for bubbles in the hole plug. In the proposed approach, a combination of non-peel ink with suitable viscosity and thixotropic properties is used to allow non-filled ink to flow into hole 110 to fill it. In various examples, the via fill ink 112 has a viscosity of from 100 to 10000 decipascal-seconds (dps-s) at 25 degrees Celsius, 200 to 1000 decipascal-seconds at 25 degrees Celsius, and / (Dps-s) in the range of 200 to 500 decafascal-seconds. The thixotropic index, which is the ratio of static viscosity to dynamic viscosity, may be 2 or more, preferably 3 or more. In some implementations, the non-peel ink 112 may also be screen printable and / or stencil printable and / or squeezable. The ink filler machine may feature a vacuum assist and / or a heater to prevent bubbles in the ink.

During the subsequent plating process, if the via fill ink is a plating resist material, the via fill ink 112 prevents the conductive material from being plated between the first conductive layer or foil 106 and the second conductive layer or foil 104 .

The via fill ink 112 may be cured or semi-cured. The vacuum drying process may be applied prior to the via fill ink 112 thermal curing process. Heat can be applied during vacuum drying to aid in debubbling vial fill. For example, the non-fired ink 112 made of a solvent can be vacuum dried. In one example, the vacuum drying conditions may be less than 360 millimeters mercury (mmHg), or 150 mmHg or less, for a time greater than 30 seconds at the set pressure or a length of time greater than 90 seconds at the set pressure. Or heat can be applied to the via fill ink for curing. Vacuum and thermal curing processes can be performed simultaneously to perform defoaming and curing of the via fill ink.

In an optional fifth step (Step E), the laminate structure 100 is provided with additional layers 120 and 122, such as one, on one or both sides of the laminate structure 100 to form the multi- Or may be added or laminated onto the laminate structures having the core structure and / or the prepreg. In one example, the additional laminate structures may include a dielectric layer and conductive layers or foils. Conductive layers (e.g., conductive foils) may be patterned to form electrical paths or traces.

In the optional sixth step (step F), the through-holes 124 can be drilled through the multilayer structure 130 and include passing through the via-fill ink 112. The through-hole 124 may have a smaller diameter than the diameter of the first forming hole 110 and / or the via-fill ink 112. The through-holes 124 can then be plated, for example, by disposing the panel into the seed bath, followed by immersion in an electroless copper bath, and subsequent electrolytic plating.

Figure 2 is a flow chart illustrating a method of forming a non-perforated thin lamination structure having a via-hole plug. A laminate structure comprising at least a dielectric layer and a first conductive foil on a first side of the dielectric layer is formed (202).

A non-perforated or blind hole is formed in the laminate structure that faces the first conductive foil and extends at least partially through the dielectric layer, and the hole has a hole depth to hole diameter aspect ratio of less than 10 (10) to 1 (1) 204). 1: 1 or less, 5: 1 or less, 4: 1 or less, 3: 1 or less, 2: 1 or less, 1: 1 or less, 1: 2 or less, Or 1:10 or less. In one example, the drill is used to form the hole, and the drill has a point angle equal to or greater than 125 degrees or equal to or greater than 155 degrees. A via fill ink may then be deposited 206 on the hole. The via fill ink may be dried and / or cured (208) to form a hole plug. Plated through holes can be formed later through the hole plug material. The hole plug may be a plating resist or material that prevents metal plating.

Additionally, the laminate structure may further comprise a second conductive foil on the second side of the dielectric layer, wherein the second conductive foil is penetrated by the hole. In one example, the laminate structure may further comprise a disposable layer on the second conductive foil. In one embodiment, the multilayer printed circuit board may be formed of a laminate structure.

In one embodiment, the holes may be formed with drills having a point angle of greater than 125 degrees. Alternatively, the hole may be formed with a drill having a point angle of greater than 155 degrees. The drill can be configured to form a bottomed corner trimmed in the hole.

In one example, the via fill ink may be deposited by at least one of: (a) screen printing, (b) stencil printing, or (c) squeegeing the via fill ink into the hole.

In some embodiments, the non-peel ink deposition can be assisted by a vacuum (e.g., in a vacuum chamber) to debravel the non-peel ink (i.e., to remove bubbles from the non-peel ink) have.

Drying and / or curing of the via fill ink can be performed, for example, in an oven.

In one example, the thermal curing process proceeds simultaneously.

In various embodiments, the first conductive foil may have a thickness of less than 12 ounces, less than 2 ounces, or less than 1 ounce (oz).

In some embodiments, the dielectric layer may have a thickness of 20 mils or less, 16 mils or less, or 12 mils or less.

laser- Drilled  Charged Via  Example with holes Non-perforated  Thin laminate structure

3 illustrates a cross-sectional view of the configuration of a non-perforated laminate structure 300 having laser-drilled filled via holes. In the first step (step A), the laminate structure 300 includes a first conductive layer or foil 306 (e.g., a copper foil) and / or a dielectric layer sandwiched between the second conductive layer or foil 304 302 as shown in FIG. Although a double-sided laminate 300 is illustrated, cross-sectional laminates (i.e., one dielectric layer and one conductive layer or foil) and / or an unclad laminate are also contemplated for use. In one example, the first conductive layer or foil 306 and the second conductive layer or foil 304 are formed using a conventionally available copper foil thickness, e.g., about 12 ounces (420 microns) ) Or less, or one ounce (35 microns) or less in thickness. In one example, the dielectric layer 302 may have a thickness of 20 mils or less (e.g., 16 mils or less, 12 mils or less, 8 mils or less).

In the second step (step B), the conformal mask forming process is performed by a chemical etchant etch process or laser to form a hole 308 exposing the dielectric layer 302 on the second conductive layer or foil 304 Can be achieved by abrasion.

In the third step (step C), laser drilling can be used to form a non-penetrating or blind hole 310 through the dielectric layer 302 of the laminate structure 300. In some embodiments, the laser may be a C0 ₂ laser, UV laser, or a composite C0 ₂ and a UV laser. If the laser aperture is not sufficient for the hole size, a common trepanning method can be used. The laser drill will be stopped by the adjacent copper foil, which makes the hole non-perforated or blind.

In the fourth step (step D), the via fill ink 312 (or other similar via fill material of similar viscosity) is deposited into the hole 310 using a hole filler machine. In one example, the hole filler machine may feature a vacuum assisted process to prevent bubbles in the via-fill ink. Once inserted into the hole 310, the via-fill ink 312 can form a hole plug. In one example, the via fill ink 312 may be a plating resist material. According to various approaches, the non-peel ink 312 can be deposited by screen or stencil printing, by an ink dispenser, by a squeegee on the surface, and these processes can be assisted by the use of vacuum. In some embodiments, the surface of the laminate substrate 300 on which the vias are formed can be made of a disposable layer such that after the non-fired ink 312 is deposited in the hole 310, the disposable layer is laminated to the laminate structure 300 ). ≪ / RTI >

1: 1 or less, 1: 2 or less, 1: 2 or less, 1: 2 or less, 10 or less aspect ratio), conventional via fill materials and / or processes do not work well.

It should be noted that conventional / thicker via fill material can not adequately fill holes 310 and conventional filler machines may be responsible for bubbles in the hole plug. Here, a combination of non-peel inks is used that has appropriate viscosity and thixotropic properties to allow non-peel ink to flow into hole 310 and fill it. In various examples, the via fill ink 312 has a viscosity of from 100 to 10000 decipers-sec (dps-s) at 25 degrees Celsius, 200-1000 decipers-sec (dps-s) at 25 degrees Celsius, and / (Dps-s) in the range of 200 to 500 decafascal-seconds. In some implementations, the non-peel ink 312 may also be screen printable and / or stencil printable and / or squeezable. The ink filler machine may feature a vacuum assist and / or a heater to prevent bubbles in the ink.

During the subsequent plating process, if the via fill ink is a plating resist material, the void fill ink 312 prevents the conductive material from being plated between the second conductive layer or foil 304 and the first conductive layer or foil 306 .

The via-fill ink 312 may then be cured or semi-cured. The vacuum drying process may be applied prior to the via fill ink 312 thermal curing process. The heat can be applied during vacuum drying to assist in defoaming the via fill ink. For example, the via-fill ink 312 may be vacuum dried. In one example, the vacuum drying conditions may be less than or equal to 360 millimeters of mercury (mmHg), or less than or equal to 150 mmHg, for a length of time greater than 30 seconds at the set pressure or greater than 90 seconds at the set pressure. Heat can be applied to the via fill ink for additional curing. Vacuum drying and thermosetting processes can proceed simultaneously.

In an optional fifth step (Step E), the laminate structure 300 may include additional layers 320 and 322 on one or both sides of the laminate structure 300 to form the multilayer structure 330, And / or on additional laminate structures. In one example, the additional laminate structures may comprise dielectric and conductive layers or foils. Conductive layers (e.g., conductive foils) may be patterned to form electrical paths or traces.

In the optional sixth step (step F), the through-hole 324 can be drilled through the multi-layer structure 330 and includes penetrating the via-fill ink 312. The through-hole 324 may have a diameter smaller than the diameter of the first formed hole 310 and / or the via fill ink 312. In one example, the through-holes 324 can then be plated, for example, by disposing the panel into the seed bath, followed by immersion in an electroless copper bath, followed by electrolytic plating.

Figure 4 is a flow chart illustrating a method of forming a thin laminate structure with a filled hole plug. A laminate structure is formed 402 comprising a dielectric layer, a first conductive foil on a first side of the dielectric layer, and a second conductive foil on a second side of the dielectric layer. The second conductive foil is then partially removed (e.g., masked and etched) 404 to form holes that expose portions of the dielectric layer on the second conductive foil. The exposed portions of the laminate structure may then be laser drilled to form non-perforated or blind holes that extend through and at least partially penetrate the dielectric layer towards the first conductive foil, Depth-to-hole diameter aspect ratio (406). The via fill ink may then be deposited (408) and cured (410) in the hole to form a hole plug. The second conductive foil is penetrated by the holes. Plated through holes can be formed through the hole plug material. The hole plug may be a plating resist or material that prevents metal plating.

Additionally, the laminate structure may further comprise a disposable layer on the second conductive foil. In one example, the multilayer printed circuit board may be formed of a laminate structure.

In various examples, the aspect ratio of the holes (via hole depth to diameter ratio) may be, for example, less than 10 to 1, less than 5 to 1, less than 4 to 1, less than 3 to 1, or less than 2 to 1, Or 1: 2 or less. In other implementations, the hole aspect ratio (via hole depth to diameter ratio) may be, for example, between 10: 1 and 1: 1, between 10: 1 and 1: 1, between 5: 1 and 1: 1, One to one, three to one and one to two, or two to one and one to one or one to two. In various implementations, via fill ink may be deposited by at least one of: (a) screen printing, (b) stencil printing, and (c) squeegeing the via fill ink into the hole.

In some embodiments, the non-peel ink deposition can be assisted by a vacuum (e.g., to remove bubbles from the non-peel ink) to degrade the non-peel ink (e.g., have).

In one example, the via fill ink can be cured in an oven. The heat conduction process can proceed at the same time.

In various examples, each of the first conductive foil and the second conductive foil may have a thickness of 12 ounces or less, 2 ounces or less, or 1 ounce or less.

In other examples, the dielectric layer has a thickness of 20 mils or less, 16 mils or less, or 12 mils or less.

Exemplary drill for hole formation

Figure 5 illustrates an exemplary drill that may be used for the holes according to Figures 1 and 2. Here, the laminate structure 502 (e.g., including a dielectric layer and not including conductive layers, or including a dielectric layer and one or more conductive layers or foils) may be shaped or configured to form a bottomed corner in the hole The hole formed by the drill 504 may be formed. The trimmed bottom corner minimizes potential bubble traps. For example, the drill may have a point angle? Greater than 125 degrees or a point angle? Greater than 155 degrees. Since the hole depth may be somewhat shallow (relative to the hole diameter), such a drill point angle may be necessary to form a hole capable of accommodating non-peel ink.

It is noted that aspects of the present disclosure may be described herein as a flow chart, a flow diagram, a structure diagram, or a process depicted as a block diagram. Although a flowchart can describe operations in a sequential process, many operations can be performed in parallel or concurrently. In addition, the order of operations may be reordered. The process is terminated when its processes are complete. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, and the like. If the process corresponds to a function, its termination corresponds to the return of the function to the calling function or main function.

The various features of the present disclosure set forth herein may be implemented in different systems and devices without departing from the present disclosure. It should be noted that the above-described aspects of the present disclosure are merely examples and are not to be construed as limiting the present disclosure. The description of aspects of the disclosure is illustrative and is not intended to limit the scope of the claims. Accordingly, these teachings can readily be applied to other types of devices, and many alternatives, modifications, and variations will be apparent to those skilled in the art.

Claims (21)

A method for forming a hole plug,
Forming a laminate structure comprising at least one dielectric layer and a first conductive foil on a first side of the dielectric layer;
Forming a non-perforated or blind hole in the laminate structure that extends from the second side of the dielectric layer at least partially through the dielectric layer toward the first conductive foil;
Depositing a via fill ink in the hole; And
Drying and / or curing the via-fill ink to form a hole plug,
Wherein the holes have a hole depth to hole diameter aspect ratio of less than 10 to 1. The method according to claim 1,
Further comprising forming a second conductive foil on the second side of the dielectric layer, wherein the second conductive foil is penetrated by the hole. The method according to claim 1,
Further comprising the step of forming the laminate structure further comprising a disposable layer on the second conductive foil. The method according to claim 1,
Further comprising forming a multilayer printed circuit board having the laminate structure. The method according to claim 1,
And forming a plated through hole through the hole plugped material. The method according to claim 1,
The hole aspect ratio is:
(a) Ten to one,
(b) five to one,
(c) 3 to 1, or
(d) less than one to one. The method according to claim 1,
Wherein the hole is formed by drilling: (a) 125 degrees, or (b) a point angle of 155 degrees or greater. The method according to claim 1,
Wherein the drill is configured to form a bottomed corner trimmed in the hole. The ink jet recording method according to claim 1,
(a) screen printing,
(b) stencil printing, or
(c) squeezing the via fill ink into the hole. The method of claim 1, wherein the non-peel ink deposition is assisted by vacuum. The method of claim 1, wherein debubbling in the non-peel ink is performed in a vacuum chamber. The method of claim 1, wherein the drying and curing of the non-fired ink is performed in an oven. The method of claim 1, wherein the thermosetting process is performed simultaneously. The method of claim 1, wherein the first conductive foil has a thickness of 12 ounces or less, 2 ounces or less, or 1 ounce or less. The method of claim 1 wherein the dielectric layer has a thickness of less than or equal to 20 mils, less than or equal to 16 mils, or less than or equal to 12 mils. The method of claim 1, wherein the hole plug is a plating resist or material that prevents metal plating. A laminated structure having a hole plug,
A laminate structure comprising at least one dielectric layer and a first conductive foil on a first side of the dielectric layer;
A non-perforated or blind hole of the laminate structure extending from a second side of the dielectric layer toward the first conductive foil; And
And a non-peel ink deposited on the hole to form a hole plug,
Wherein the holes have a hole depth to hole diameter aspect ratio of 10 to 1. < RTI ID = 0.0 > 11. < / RTI > 18. The method of claim 17,
Further comprising a second conductive foil, said second conductive foil being penetrated by said hole. 18. The method of claim 17,
Further comprising a plurality of conductive and dielectric layers coupled to the laminate structure to form a multilayer printed circuit board. 20. The method of claim 19,
And a plated through hole through the hole plug material. A method for forming a hole plug,
Forming a laminate structure comprising a dielectric layer, a first conductive foil on a first side of the dielectric layer, and a second conductive foil on a second side of the dielectric layer;
Partially removing the second conductive foil to form an opening exposing a portion of the dielectric layer on the second conductive foil;
Performing laser drilling through the exposed portion of the laminate structure to form a non-perforated or blind hole that extends toward at least partially through the dielectric layer toward the first conductive foil;
Depositing a via fill ink in the hole; And
And curing the via-fill ink to form a hole plug,
Wherein the holes have a hole depth to hole diameter aspect ratio of 10 to 1.

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