WO2017115332A1

WO2017115332A1 - Reamer-drill bit for drilling and smoothing a hole in a component carrier

Info

Publication number: WO2017115332A1
Application number: PCT/IB2016/058112
Authority: WO
Inventors: Sally SUN; Yee-Bing LING; Nikolaus BAUER-ÖPPINGER
Original assignee: At&S (China) Co. Ltd.
Priority date: 2015-12-30
Filing date: 2016-12-30
Publication date: 2017-07-06
Also published as: CN205733157U

Abstract

A reamer-drill bit for drilling and smoothing a hole in a component carrier, wherein the reamer drill bit comprises a front drill section for drilling the hole in the component carrier, wherein the front drill section comprises a drilling tip and at least three cutting edges spaced apart from each other along a drilling rotation direction, wherein the cutting edges comprise at least one component extending from the drilling tip along a rotational axis of the reamer-drill bit, and a rear reamer section for smoothing the hole, wherein the rear reamer section extends from the front drill section along the rotational axis.

Description

Reamer-drill bit for drilling and smoothing a hole in a component carrier

The invention relates to a reamer-drill bit and a method of drilling and smoothing a hole in a component carrier.

Conventionally a drill bit consists of a body, comprising the drill section, a shank with which the bit is held and two cutting edges for drilling a hole into a solid material.

US 2013/058734 Al discloses a drill-reamer which comprises a shank portion and a cutting portion which is coaxial with the shank portion. The cutting portion has an operational portion comprising at least one twist drill spiral roughing cutting edge associated with a land margin, a land clearance and a flute. Further the cutting portion comprises at least one spiral finishing edge interlaces with the spiral roughing cutting edge and having associated therewith only a land margin and a flute. The land margin of said finishing edge is formed by a plurality of reamer cutting edges spiraling in an opposite direction to that of the cutting edge. The reamer cutting edge is configured to cut a larger hole than said edge.

With continuous demand for tighter holes and increasing hole density with improved performance at lower costs, there is still room for improved drill and reamer solutions.

With increasing complexity of electronic circuits and increasing requirements for tight tolerances, the latter become more and more prone to failure as a result of stability of the drilled holes, size of the hole, accuracy of the hole and performance of the hole quality. The specifications for drill bits become tighter and tighter, which results in increased requirements for the drill bits.

It is an object of the invention to provide a reamer-drill bit which allows for increasing the accuracy of the size of the hole and the quality of the hole.

In order to achieve the object defined above, a reamer-drill bit and a method for drilling and smoothing a hole in a component carrier according to the independent claims are provided.

According to an exemplary embodiment of the invention, a reamer- drill bit for drilling and smoothing a hole in a component carrier (i.e. a carrier structure in and/ or on which one or more electronic components may be mounted) is provided. The reamer-drill bit comprises a front drill section for drilling the hole in the component carrier. The front drill section comprises a drilling tip and at least three cutting edges spaced apart from each other along a drilling rotation direction. The cutting edges comprise at least one

component extending from the drilling tip along a rotational axis of the reamer-drill bit. The reamer-drill bit further comprises a rear reamer section for smoothing the hole, wherein the rear reamer section extends from the front drill section along the rotational axis.

According to another exemplary embodiment of the invention, a method for drilling and smoothing a hole in a component carrier by a reamer- drill bit is provided. The method comprises the step of drilling the hole in the component carrier by a front drill section of the reamer-drill bit, wherein the front drill section comprises a drilling tip and at least three cutting edges spaced apart from each other along a drilling rotation direction. The cutting edges comprise at least one component extending from the drilling tip along a rotational axis of the reamer-drill bit. The method further comprises the step of smoothing the hole by a rear reamer section of the reamer-drill bit, wherein the rear reamer section extends from the front drill section along the rotational axis.

In the context of the present application, the term "component carrier" may particularly denote any support structure which is capable of

accommodating one or more electronic components thereon and/ or therein for providing both mechanical support and electrical connectivity.

In the context of the present application the term "reamer-drill bit" may particularly denote a tool for drilling and reaming a hole, in particular a rotating cutting tool. In particular the tool is a type of rotary cutting tool, drilling tool, regroover, boring tool or reaming tool used for making, in particu- lar cutting, a hole in a component carrier along the axis of the reamer-drill bit. The front drill section of the reamer-drill bit is drilling or boring into a material for forming a hole into the material. However, the drilled part of the material may not have the required smooth surface finish inside the drilled hole. Therefore, the step of drilling is followed by the step of reaming by the rear reamer section which provides a smoothed surface or smoothed sides of the hole. In particular, the step of reaming leads to a smoother surface and/or the sites of the hole. The process of reaming enlarges the diameter of the drilled hole. When the hole is enlarged by the rear reamer section the hole may have a high degree of accuracy and leaves a smooth surface, such that tight tolerances of the hole may be achieved. In the context of the present application the term "cutting edges" may particularly denote an edge for drilling the hole in the component carrier or another material. The cutting edge may be a sharpened edge for remove a part of a component or a material. The front drill section of the reamer-drill bit comprises the cutting edges.

According to an exemplary embodiment of the invention, an improved reamer-drill bit is provided by which an increased accuracy of the drilled hole with more exact tolerances is obtained. This is achieved by the reamer-drill bit according to the present invention which is able to drill and smooth in one drilling step a hole in a component carrier.

A component carrier comprises electrical conductive paths. For connect - ing those conductive paths holes need to be drilled into the component carrier, which holes will be filled with copper to provide a conductive connection (via) for the conductive paths. When the amount of needed connections increases the amount of holes and therefore the density of the holes at a component carrier increases. For providing an ensured continuous process with a stable output the drilling has to be conducted faster. For this reason the drilling and reaming of a hole is combined by the presented reamer drill bit such that the drilling and reaming is conducted. Hence, the hole formation is done by the front drill section of the reamer-drill bit and the smoothing of the surface of the hole is done by the rear reamer section of the reamer-drill bit. The holes for the connection of the conductive paths comprise a small dimension (i.e. diameter).

For achieving a stable hole formation and a high accuracy the front drill section of the reamer-drill bit comprises at least three cutting edges for removing material of the component carrier.. In this way the hole in the component carrier is drilled with a front drill section for having at least three cutting edges and with the rear reamer section the hole is smoothed. With this embodiment smaller tolerances for the hole are achieved, in the hole may have a diameter tolerance of approximately +50 μιτι to -0 μηι, a length tolerance of approximately ± 50 μηη and a hole angle of approximately ± 5°, wherein the standard tolerances of a hole are approximately ± 50 μιη in width, a tolerance of approximately ±80 μιη in length and an angle tolerance of approximately ± 15°. The reamer-drill bit may be used for rotations of approximately 70000 rpm for manufacturing about 2000 bores. After the first amount of around 2000 bores the reamer-drill bit can be sharpened e.g. twice a time before the reamer-drill bit has to be exchanged.

In the following, further exemplary embodiments of the reamer-drill bit and the method will be explained.

In an embodiment, the cutting edges are symmetrically spaced apart from each other along the drilling rotation direction. In other words the cutting edges are arranged with the same distance between each other, along the drilling rotation direction. The symmetrically arrangement provides a better force distribution, in particular are balanced force distribution during the drilling of the hole.

According to an exemplary embodiment, at least two cutting edges are arranged in such a way that an angle of approximately 120 degrees along the drilling rotation direction between each other exists. In other words the cutting edges are arranged symmetrically around the circumferential direction of the reamer-drill bit with the same distance. Having symmetrical arranged cutting edges a stable guidance and support in the machining process during drilling is provided and therefore a stable hole forming process can be achieved. An added third cutting edge improves the processing precision during the forming, i.e. the drilling, of the hole and during the smoothing, i.e. the reaming, of the hole. This may decrease the verticality hole roughness.

According to an exemplary embodiment, the front drill section for drilling the hole in the component carrier comprises four cutting edges. By providing more than three cutting edges, in particular four cutting edges, a balanced force distribution is improved during the drilling and smoothing process with the reamer-drill bit. Further, the processing precision during the forming, i.e. the drilling of the hole and during the smoothing, i.e. the reaming, of the hole can be increased. This may increase the precision of the verticality and the hole roughness. Furthermore, the hole quality can be improved, therefore the hole stability and a high accuracy can be achieved, with this a the drilling capability is improved.

According to an exemplary at least two cutting edges are arranged in such a way that an angle of 90 degrees between each other along the drilling rotation direction exists. In other words the four cutting edges are arranged symmetrically along the drilling rotation direction with an angle of 90 degrees. The design with four cutting edges may provide a stable positioning when starting to drill. By the provided four cutting edges, the drilling process and further the reaming process are more stable. The drilled hole accuracy and the reamed hole accuracy may be increased. Further the precision of the dimensional tolerance is increased with applying four cutting edges during a hole forming process.

According to an exemplary embodiment, the rear reamer section comprises at least one land part, wherein the land part comprises at least one margin section having a margin edge for smoothing a hole, wherein the margin section extends from one of the cutting edges along the rotational axis, and a land section extending from the margin section along the drilling rotation direction and along the rotational axis. In other words, the land part has one or two margin sections and a land section at the margin section. The land section is associated or adjacent with the margin section and is extending in the same manner as the margin section, such that they extending together in the same direction. For example, when the land part comprises two margin sections, the land section is arranged between those two margin sections. In the context of the present embodiment, the term "margin section" may particularly denote a blade section, for example a reaming blade section or a margin section of the reamer-drill bit. The margin section comprises a margin edge or a reaming edge. In particular the end point of each margin section is a margin edge. The margin edge is the first edge of the margin section

contacting the material of the component carrier. The land part may comprise one or two margin section and therefore may comprise one or two margin edges, respectively. If there are two margin edges, the reamer-drill bit may comprise a total of four margin edges. Hence, with this arrangement a homogenous force distribution may be provided. With multiple margin edges arranged at the reamer-drill bit, the stress acting on the reamer drill bit can be shared. The margin sections are also arranged symmetrically along the circumference of the reamer-drill bit.

According to an exemplary embodiment the land part extends in a spiral manner along the rotational axis. For example, the land part is extending in a spiral along the circumference of the reamer-drill bit. Further, the land part is extending in a spiral manner from the end of the front drill section to the end of the rear reamer section, such that it extends along the rotational axis.

According to an exemplary embodiment the rear reamer section comprises at least three margin sections. For example one land part comprises two margin sections and another land part comprises one margin section. By providing this embodiment the reamer-drill bit comprises three margin sections, with which the reamer-drill bit is able to smooth the sites and/ or the surface of the hole. The margin sections are also arranged symmetrically along the drilling rotation direction, as a result of their arrangement at the cutting edges. Hence, by three margin sections a balanced force distribution may be achieved.

According to an exemplary embodiment, the margin section protrudes in radial direction from the land part. For example the margin section protrudes in a rectangular manner from the land part, such that two edges are formed at the margin section, wherein one of the two edges is the margin edge. By protruding from the land part the margin is provided, such that the reamer- drill bit is able to conduct the drilling and smoothing of the component carrier.

According to an exemplary embodiment, the reamer-drill bit consists of iron, in particular of steel. The surface of the material of the reamer-drill bit does not comprise a surface coating for hardening the surface of the reamer- drill bit. This advantageously reduces the cost of the reamer-drill bit during the production thereof.

According to an exemplary embodiment, the drilling tip and a rear end of the cutting edge are spaced apart from each other along a radial direction with respect to the rotational drilling axis, such that the cutting edge extends from the rear reamer section to the drilling tip in a tapered manner along the rotational axis. Therefore, an envelope of the front drill section comprises a tapering shape. In other words, the front drill section is tapering from the end of the rear reamer section to the other side the drilling tip from the reamer- drill bit. As one could say the front drill section comprise a conical shape. The rear end of the front drill section has the same diameter as the front end of the rear reamer section for providing a step free transition between the front drill section and the rear reamer section parts.

In an embodiment, a distance of the margin edge to the rotational axis is constant along the rotational axis. In other words, the rear reamer section is not tapering along the rotational axis, such that it comprises a constant diameter along the whole length. Hence, a homogenous and stable hole size and hole quality may be achieved. Therefore, the reamer-drill bit is able to smooth the sides and/ or the surface of the hole with tight tolerances.

According to an exemplary embodiment, between two adjacent land parts a rear flute is formed. In the context of the present application, the term "flute" may particular denote a channel, a notch, or a groove for guiding the removed material (e.g. the chips) of the component carrier out of the hole. Further, the flutes are spiral grooves which extend along the rotational axis of the reamer-drill bit. By forming a rear flute between two adjacent land parts the rear reamer section is comprising this rear flute, in particular the rear reamer sections comprises two rear flutes. More in particular, at each of the land parts a rear flute is formed, whereby the rear reamer part comprises at least two rear flutes.

According to an exemplary embodiment, between two cutting edges a front flute is formed. The front flute may be provided for guiding the removed material of the component carrier during the drilling, such that the material may not block the drilling process. Further, the flute allow for a coolant, e.g. air or a cooling fluid, to get down to the cutting edge, which may prevent the drilling process for overheating. For example, the front drill section may comprise two front flutes between the land parts. With the material guided out of the hole, the drilling process is not disabled and a stable drilling process is provided.

According to an exemplary embodiment, the amount of the front flutes and the amount of the rear flutes are equal, such that the front drill section and the rear reamer section comprise the same amount of respective flutes. In particular the front drill section and the rear reamer section comprise at least one flute. More in particular, the front drill section and the rear reamer section comprise two flutes. With the provided front and rear flutes the removed material from the component carrier is managed out of the hole. For example, with two flutes the capacity for removing the material is increased.

According to an exemplary embodiment, the front flutes and the rear flutes are formed in such a way, that the front flutes merge into the rear flutes. In other words, the front flutes migrate into the rear flutes. In particular, the front flutes and the rear flutes form one single flute along the length of the front drilling section and the rear reamer section. More in particular, when the front drill section and the rear reamer section each comprise two flutes, the first front flute and the first rear flute may form a first single flute and the second front flute and the second rear flute may form a second single flute. Therefore, with the merging front and rear flutes a step free transition between the front drill section and the rear reamer section may be provided. Further, the complexity of the reamer-drill bit is held simple thereby decreasing the manufacturing complexity of the reamer-drill bit.

In an embodiment, the component carrier comprises or consists of a stack of at least one electrically insulating layer structure and at least one electrically conductive layer structure. For example, the component carrier may be a laminate of the mentioned electrically insulating layer structure(s) and electrically conductive layer structure(s), in particular formed by applying mechanical pressure, if desired supported by thermal energy. The mentioned stack may provide a plate-shaped component carrier capable of providing a large mounting surface for further electronic components and being nevertheless very thin and compact. The term "layer structure" may particularly denote a continuous layer, a patterned layer or a plurality of non-consecutive islands within a common plane.

In an embodiment, the at least one electrically insulating layer structure comprises at least one of the group consisting of resin, in particular Bismalei- mide-Triazine resin, cyanate ester, glass, in particular glass fibers, prepreg material, polyimide, liquid crystal polymer, epoxy-based Build-Up Film, FR4 material, a ceramic, and a metal oxide. Although prepreg or FR4 are usually preferred, other materials may be used as well.

In an embodiment, the at least one electrically conductive layer struc- ture comprises at least one of the group consisting of copper, aluminum, and nickel. Although copper is usually preferred, other materials are possible as well.

In an embodiment, the component carrier is shaped as a plate. This contributes to the compact design of the electronic device, wherein the component carrier nevertheless provides a large basis for mounting electronic components thereon. Furthermore, in particular a naked die as preferred example for an embedded electronic component, can be conveniently embedded, thanks to its small thickness, into a thin plate such as a printed circuit board.

In an embodiment, the component carrier is configured as one of the group consisting of a printed circuit board, and a substrate.

In the context of the present application, the term "printed circuit board" (PCB) may particularly denote a plate-shaped component carrier which is formed by laminating several electrically conductive layer structures with several electrically insulating layer structures, for instance by applying pressure, if desired accompanied by the supply of thermal energy. As preferred materials for PCB technology, the electrically conductive layer structures are made of copper, whereas the electrically insulating layer structures may comprise resin and/or glass fibers, so-called prepreg or FR4 material. The various electrically conductive layer structures may be connected to one another in a desired way by forming through-holes through the laminate, for instance by laser drilling or mechanical drilling, and by filling them with electrically conductive material (in particular copper), thereby forming vias as through-hole connections. Apart from one or more electronic components which may be embedded in a printed circuit board, a printed circuit board is usually configured for accommodating one or more electronic components on one or both opposing surfaces of the plate-shaped printed circuit board. They may be connected to the respective main surface by soldering.

In the context of the present application, the term "substrate" may particularly denote a small component carrier having substantially the same size as an electronic component to be mounted thereon.

In an embodiment, the component carrier is a laminate-type component carrier. In such an embodiment, the component carrier is a compound of multiple layer structures which are stacked and connected together by applying a pressing force, if desired accompanied by heat. The aspects defined above and further aspects of the invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to these examples of embodiment.

Fig. 1 shows a side view of a reamer-drill bit according to an exemplary embodiment of the invention.

Fig. 2 shows a front sectional side view of a reamer-drill bit according to an exemplary embodiment of the invention.

Fig. 3 shows a cross-sectional view of a reamer-drill bit according to an exemplary embodiment of the invention.

Fig. 4 shows a front sectional side view of a reamer-drill bit according to an exemplary embodiment of the invention.

The illustrations in the drawings are schematically. In different drawings, similar or identical elements are provided with the same reference signs.

In the following, referring to Fig 1 and Fig. 2 a reamer-drill bit according to an exemplary embodiment will be described. The reamer-drill bit 101 comprises a front drill section 103 for drilling the hole in the component carrier, wherein the front drill section 103 comprises a drilling tip 208 and at least three cutting edges 201a, 201b, 201c spaced apart from each other along a drilling rotation direction C. Thee cutting edges 201a, 201b, 201c comprise at least one component extending from the drilling tip 208 along a rotational axis A of the reamer drill bit 101. The reamer-drill bit 101 further comprises a rear reamer section 104 for smoothing the hole, wherein the rear reamer section 104 extends from the front drill section 103 along the rotational axis A. The portion which extends from the end of the rear reamer section 104 can be the shank, with which the reamer-drill bit 101 is clamped into a machine. The front drill section 103 has a smaller length than the rear reamer section 104. The front drill section 103 and the rear reamer section have the same middle axis, namely the rotational axis A.

For example, typical dimension of the reamer-drill bit are: the flute length may be from 50 μηη to 15 mm, in particular 2 mm to 10.5 mm, for example 4 mm. Possible diameters of the reamer-drill bit may be from 0.2 mm to 6 mm, in particular 0.4 mm to 3.15 mm .

As can be taken more detailed from Fig. 2, the cutting edges 201a, 201b, 201c are symmetrically spaced apart from each other along the drilling rotation direction C, such that the cutting edges 201 a, 201b, 201c have the same distance from each other. At least two cutting edges, for example the cutting edges 201a and 201b, are arranged in such a way that an angle of 120 degrees along the drilling rotation direction between each other exists. For example between all three cutting edges 201a, 201b and 201c exists an angle of 120 degrees, such that the cutting edges 201a, 201b, 201c are spaced apart with the same distance.

The rear reamer section 104 comprises at least one land part, wherein the land part comprises at least one margin section, e.g. 102b or 102a, having a margin edge 206a, 206b for smoothing the hole, wherein the margin section 102a, 102b extends from one of the cutting edges 206a, 206b along the rotational axis A, and a land section 207 extending from the margin section 102a, 102b along the drilling rotation direction and along the rotational axis A. In Fig. 2 the third margin section, the third margin edge and the second land part are not visible in this side view. The reamer-drill bit 101 according to Fig. 2 comprises two land parts. Hence, one land part comprises of two margin sections, 102a and 102b, each having one cutting edge, 206a and 206b and a land section 207 (wherein the visible land section may be denoted as 207a). The margin sections 102a, 102b are located between the end of the cutting edges and the end of the rear reamer section 104, for example the start of margin section 102a is the end of cutting edge 201a and the start of margin section 102b is the end of cutting edge 201b.

The land part extends in a spiral manner along the rotational axis A. with the land part the margin section, e.g. 102a and 102b, and the land section extend in a spiral manner along the rotational axis A. Hence the margin edges also extend in a spiral manner along the rotational axis A.

The rear reamer section 104 comprises at least three margin sections 102a, 102b and the third margin section is not visible.

The drilling tip 208 and a rear end of the cutting edge 201a, 201b, 201c are spaced apart from each other, such that the cutting edge 201a, 201b, 201c extends from the rear reamer section 104 to the drilling tip 208 in a tapered manner along the rotational axis A. As can be seen in the Fig. 2 the shape of the front drill section 103 is tapering from the right side in Fig. 2, the end of the front drill section 103 and the start of the rear reamer section 104, to the left side in Fig. 2, the drilling tip 208. The shape of the tapering is formed by the cutting edges 201a, 201b, 201c. The free end of the reamer- drill bit 101 is the drilling tip 208. The widest diameter of the front drill section 103 is formed at the end of the front drill section 103, where the rear reamer section 104 begins to extend.

A distance of the margin edge 206a, 206b to the rotational axis A is constant along the rotational axis A, such that the shape of the rear reamer section 104 is cylindrical. This means the whole shape of the rear reamer section 104 has the same diameter along the whole length. Hence, the dis- tance of the margin sections 206a, 206b (and the not visible third margin section) from the rotational axis is the same and they are ending at the same diameter. The widest diameter of the rear reamer section 103 is formed by the extended margin sections 206a, 206b and the not visible third margin section. Between two adjacent land parts a rear flute 105a or 105b is formed. In this embodiment the rear flute 105a or 105b may be a groove located between two land parts, such that at one site of the rear flute 105a one margin section, e.g. 102a, is located and on the other side the non-visible margin section is located. At the one side of the second rear flute 105b the not visible land section 207b is located and at the other site the margin section 102b is located. With this embodiment a reamer-drill bit 101 with two flutes 105a, 105b and three cutting edges 201a, 201b, (and a non-visible one) and three margin edges 206a, 206b, (and a non-visible one) is described.

Between two cutting edges, e.g.201a, 201b or 201c, a front flute is formed. In this embodiment the front flute is located between the cutting edges 201b and 201c and a second front flute is located between the cutting edge 201a and a not visible land section.

The amount of the front flutes and the amount of the rear flutes 105a, 105b are equal. For example, if the reamer-drill bit 101 comprises two front flutes, then it comprises also two rear flutes. Further, the front flutes and the rear flutes 105a, 105b are formed in such a way, that the front flutes merge into the rear flutes 105a, 105b. For example the front and the rear flutes form one common flute, such that the first front flute is the first rear flute 150a and the second front flute is the second rear flute 105b. As can be seen in Fig. 2 no step is visible between the passages of the front flutes to the rear flutes.

In this embodiment, the reamer-drill bit 101 comprises a step free transition between the front drill section 103 and the rear reamer section 104. In the context of the present application, the term "step free transition" may particularly denote that the transition or passage of the front drill section 103 and the rear reamer section 104, i.e. where those two parts are joined together, is step less, such that the surfaces of both parts do not comprise a step. Furthermore, the surfaces of both parts are at the same level. The reamer-drill bit 101 may be formed of one piece.

In the following, referring to Fig. 3, a reamer-drill bit according to an exemplary embodiment will be described. In Fig. 3, the reamer-drill bit 101 comprises four cutting edges 201a, 201b, 201c, 401d (can be seen in Fig. 4)The cutting edges 201a, 201b, 201c, 401d and the enclosed margin edges 102a, 102b, 302c, 302d, respectively, are spaced apart from each other with an angle a of 90 degrees.

The margin sections 102a, 102b, 302c, 302d protrude in the radial direction B from the land part. In this embodiment all four margin sections 102a, 102b, 302c, 302d extend from the rotating axis A along the radial direction B and are spaced apart from each other with an angle a of 90 degrees-. In other embodiments also further three margin sections may extend from the rotating axis A along the radial direction B and are spaced apart from each other with an angle a of 120 degrees. As can be seen Fig. 3, all four margin sections 102a, 102b, 302c, 302d are protruding from the land part. If the margin sections 102a, 120b, 302c, 302d are protruding in a rectangular manner (a = 90 degrees), the margin edges 206a, 206b, 306c, 306d are formed in Fig. 3 in counterclockwise direction) behind the cutting edges 201a, 201b, 201c, 401d. Regarding the arrangement of the margin edges 206a, 206b, 306c, 306d, the reamer-drill bit 101 is drilling and smoothing the component carrier with a rotation in the drilling rotation direction C . As can be seen in Fig. 3, two in rotation direction C opposing margin sections, for example margin sections 102a and 302c, are formed on straight side of the flutes 105a, 105b and the other opposing margin sections, for example the margin sections 102b and 302d, are formed on a curved side of the flutes 105a, 105b.

In the following, referring to Fig. 4, a reamer-drill bit 100 according to an exemplary embodiment is described.

The front drill section 103 comprises four cutting edges 201a, 201b, 201c, and 401d. At least two cutting edges, for example 201a and 201b, are arranged in such a way that an angle a of 90 degrees between each other along the drilling rotation direction exists. In particular between all four cutting edges 201a, 201b, 201c, 402d exists an angle a of 90 degrees.

In this embodiment the rear flute 105a or 105b may be a groove located between two land parts, such that at one site of the rear flute 105a one margin section, e.g. 102a, is located and on the other site of the rear flute 150a margin section 302d is located. At the one side of the second rear flute 105b the not visible land section 207b with the not visible margin section 402c is located and at the other site the margin section 102b is located. By this embodiment, a reamer-drill bit 101 with two flutes and four cutting edges 201a, 201b, 201c, 401d and four margin edges 102a, 102b, 302c, 302d is described.

Between two cutting edges, e.g.201a, 201b or 201c, a front flute is formed. In this embodiment the front flute is located between the cutting edges 201b and 201c and a second front flute is located between the cutting edges 201a and 401d.

Additionally, the following is disclosed :

A method for drilling and smoothing a hole in a component carrier by a reamer-drill bit (101), wherein the method comprises:

drilling the hole in the component carrier by a front drill section (103) of the reamer-drill bit (101),

wherein the front drill section (103) comprises a drilling tip (208) and at least three cutting edges (201a, 201b, 201c, 401d) spaced apart from each other along a drilling rotation direction (C),

wherein the cutting edges (201a, 201b, 201c, 401d) comprise at least one component extending from the drilling tip (208) along a rotational axis (A) of the reamer-drill bit (101);

smoothing the hole by a rear reamer section (104) of the reamer-drill bit (101),

wherein the rear reamer section (104) extends from the front drill sec- tion (103) along the rotational axis.

It should be noted that the term "comprising" does not exclude other elements or steps and the "a" or "an" does not exclude a plurality. Also elements described in association with different embodiments may be combined.

It should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims.

Implementation of the invention is not limited to the preferred embodiments shown in the figures and described above. Instead, a multiplicity of variants are possible which use the solutions shown and the principle according to the invention even in the case of fundamentally different embodiments.

Claims

Claims:

1. A reamer-drill bit (101) for drilling and smoothing a hole in a component carrier, wherein the reamer drill bit (101) comprises:

a front drill section (103) for drilling the hole in the component carrier, wherein the front drill section (103) comprises a drilling tip (208) and at least three cutting edges (201a, 201b, 201c) spaced apart from each other along a drilling rotation direction (C),

wherein the cutting edges (201a, 201b, 201c) comprise at least one

component extending from the drilling tip (208) along a rotational axis (A) of the reamer-drill bit (101);

a rear reamer section (104) for smoothing the hole,

wherein the rear reamer section (104) extends from the front drill section (103) along the rotational axis (A).

2. The reamer-drill bit (101) according to claim 1,

wherein the cutting edges (201a, 201b, 201c) are symmetrically spaced apart from each other along the drilling rotation direction (C).

3. The reamer drill-bit (101) according to claim 1 or 2,

wherein at least two cutting edges (201a, 201b, 201c) are arranged in such a way that an angle of 120 degrees along the drilling rotation direction (C) between each other exists.

4. The reamer-drill bit (101) according to claim 1 or 2,

wherein the front drill section (103) for drilling the hole in the component carrier comprises four cutting edges (201a, 201b, 201c, 401d).

5. The reamer-drill bit (101) according to claim 4,

wherein at least two cutting edges (201a, 201b, 201c, 401d) are arranged in such a way that an angle of 90 degrees between each other along the drilling rotation direction (C) exists.

6. The reamer-drill bit (101) according to any of the preceding claims, wherein the drilling tip (208) and a rear end of the cutting edge (201a, 201b, 201c, 401d) are spaced apart from each other, such that the cutting edge (201a, 201b, 201c, 401d) extends from the rear reamer section (104) to the drilling tip (208) in a tapered manner along the rotational axis (A).

7. The reamer drill bit (101) according to any of the preceding claims, wherein the rear reamer section (104) comprises at least one land part, wherein the land part comprises

at least one margin section (102a, 102b, 302c, 302d) having a margin edge (206a, 206b, 306c, 306d) for smoothing a hole, wherein the margin section (102a, 102b, 302c, 302d) extends from one of the cutting edges (201a, 201b, 201c, 401d) along the rotational axis (A), and

a land section (207a, 207b) extending from the margin section (102a, 102b, 302c, 302d) along the drilling rotation direction (C) and along the rotational axis (A).

8. The reamer-drill bit (101) according to claim 7, wherein the land part extend in a spiral manner along the rotational axis (A).

9. The reamer-drill bit (101) according to claim 7 or 8,

wherein the rear reamer section (104) comprises at least three margin sections (102a, 102b, 302c, 302d),

10. The reamer-drill bit (101) according to claim7 to 9,

wherein the margin section (102a, 102b, 302c, 302d) protrudes in radial direction (B) from the land part.

11. The reamer-drill bit (101) according to one of the claims 7 to 10, wherein a distance of the margin edge (206a, 206b, 306c, 306d) to the rotational axis (A) is constant along the rotational axis (A).

The reamer-drill bit (101) according to one of the claims 7 to 11, wherein between two adjacent land parts a rear flute (105a, 105b) is formed.

13. The reamer-drill bit (101) according to any of the preceding claims, wherein between two cutting edges (201a, 201b, 201c, 401d) a front flute is formed.

14. The reamer-drill bit (101) according to claim 12 and 13,

wherein the amount of the front flutes and the amount of the rear flutes (105a, 105b) are equal.

15. The reamer-drill bit (101) according to claim 12 and 13,

wherein the front flutes and the rear flutes (105a, 105b) are formed in such a way, that the front flutes merge into the rear flutes (105a, 105b).

16. A component carrier with a hole drilled and smoothed by a reamer-drill bit (101) according to any of the preceding claims, wherein the component carrier comprises or consists of a stack of at least one electrically insulating layer structure and at least one electrically conductive layer structure.

17. The component carrier according to claim 16, wherein the at least one electrically insulating layer structure comprises at least one of the group consisting of resin, in particular Bismaleimide-Triazine resin, cyanate ester, glass, in particular glass fibers, prepreg material, polyimide, liquid crystal polymer, epoxy-based Build-Up Film, FR4 material, a ceramic, and a metal oxide.

18. The component carrier according to any of claims 16 to 17, wherein the at least one electrically conductive layer structure comprises at least one of the group consisting of copper, aluminum, and nickel.

19. The component carrier according to any of claims 1 to 18 wherein the component carrier is shaped as a plate.

20. The component carrier according to any of claims 1 to 19, wherein the component carrier is configured as one of the group consisting of a printed circuit board, and a substrate.

21. The component carrier according to any of claims 1 to 20, wherein the component carrier is a laminate-type component carrier.