US-12621937-B2 - Package substrate including core with trench vias and planes

Abstract

Embodiments disclosed herein comprise package substrates and methods of forming package substrates. In an embodiment, a package substrate comprises a core substrate. A hole is disposed into the core substrate, and a via is disposed in the hole. In an embodiment, the via completely fills the hole. In an embodiment, a method of forming a package substrate comprises exposing a region of a core substrate with a laser. In an embodiment, the laser changes the morphology of the exposed region. The method may further comprise etching the core substrate, where the exposed region etches at a faster rate than the remainder of the core substrate to form a hole in the core substrate. The method may further comprise disposing a via in the hole.

Inventors

• Telesphor Kamgaing

Assignees

• INTEL CORPORATION

Dates

Publication Date

20260505

Application Date

20210604

Claims (20)

1. 1 . A package substrate, comprising: a core substrate; a hole into the core substrate, and a trench into the core substrate, the trench laterally spaced apart from the hole, wherein the hole does not pass entirely through a thickness of the core substrate; a via in the hole, wherein the via completely fills the hole, and wherein the via has an outermost surface at a same level as an outermost surface of the core substrate, the outermost surface of the via having a maximum diameter less than a vertical thickness of the via through the core substrate; and a via plane in the trench.
2. 2 . The package substrate of claim 1 wherein the core substrate comprises a glass, a silicon, a ceramic, or a nonconductive semiconductor.
3. 3 . The package substrate of claim 2 , wherein the core substrate comprises the glass, and wherein the glass is a photo-definable glass.
4. 4 . The package substrate of claim 1 , wherein the hole passes entirely through a thickness of the core substrate.
5. 5 . The package substrate of claim 1 , wherein the hole has sidewalls that are sloped.
6. 6 . The package substrate of claim 5 , wherein the sidewalls have a slope that is approximately 10° or less.
7. 7 . The package substrate of claim 5 , wherein the sidewalls form an hourglass shaped cross-section.
8. 8 . The package substrate of claim 1 wherein the hole is elongated to form a trench into the core substrate.
9. 9 . The package substrate of claim 1 , wherein the hole is circular.
10. 10 . The package substrate of claim 1 , wherein the hole is rectangular.
11. 11 . The package substrate of claim 1 , wherein the hole is rectangular with rounded ends.
12. 12 . The package substrate of claim 1 , further comprising a second hole and a second via filling the second hole.
13. 13 . The package substrate of claim 12 , wherein the second hole intersects the first hole.
14. 14 . The package substrate of claim 1 , further comprising: a buildup layer over a surface of the core substrate.
15. 15 . The package substrate of claim 1 , wherein the core substrate has a thickness that is approximately 200 μm or greater, and wherein a diameter of the hole is approximately 50 μm or smaller.
16. 16 . A method of forming a package substrate, comprising: exposing a region of a core substrate with a laser, wherein the laser changes the morphology of the exposed region; etching the core substrate, wherein the exposed region etches at a faster rate than the remainder of the core substrate to form a hole in the core substrate, and to form a trench into the core substrate, the trench laterally spaced apart from the hole; forming a via in the hole, wherein the via has an outermost surface at a same level as an outermost surface of the core substrate, the outermost surface of the via having a maximum diameter less than a vertical thickness of the via through the core substrate; and forming a via plane in the trench.
17. 17 . The method of claim 16 , wherein a first surface of the core substrate and a second surface of the core substrate are exposed with the laser.
18. 18 . The method of claim 17 , wherein the hole has an hourglass shaped cross-section.
19. 19 . The method of claim 16 , wherein the hole passes through an entire thickness of the core substrate.
20. 20 . The method of claim 16 , wherein the hole does not pass through an entire thickness of the core substrate.

Description

TECHNICAL FIELD Embodiments of the present disclosure relate to electronic packages, and more particularly to package substrates with core layers that include vias and vertical planes for improved performance. BACKGROUND Microelectronic packages utilize through package vias to enable power and signal connectivity between the die and socket or printed circuit board. For the most advanced packages, the package substrate stack-up comprises a core that is made out of glass-fiber reinforced epoxy or copper clad laminate (CCL). In the client and server space, using a thick core is necessary to reduce the package warpage. Creating small diameter and fine pitch vias across such thick cores is challenging. This leads to excessive parasitics, substantial impedance discontinuities and low via density in the core. This further results in low integration density, low frequency bandwidth, and low bandwidth density for signals transitioning between the first level and second level interconnects. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a cross-sectional illustration of a glass core with top and bottom surfaces that are being exposed with a laser, in accordance with an embodiment. FIG. 1B is a cross-sectional illustration of the glass core with regions that have their morphology altered by the laser, in accordance with an embodiment. FIG. 1C is a cross-sectional illustration of the glass core with a via hole through a thickness of the glass core, in accordance with an embodiment. FIG. 1D is a cross-sectional illustration of the glass core with a via through the thickness of the glass core, in accordance with an embodiment. FIG. 2A is a plan view illustration of the glass core with a plurality of circular vias, in accordance with an embodiment. FIG. 2B is a plan view illustration of the glass core with a plurality of rectangular vias, in accordance with an embodiment. FIG. 2C is a plan view illustration of the glass core with a via plane that is rectangular, in accordance with an embodiment. FIG. 2D is a plan view illustration of the glass core with a via plane that is rectangular with rounded edges, in accordance with an embodiment. FIG. 2E is a plan view illustration of the glass core with intersecting via planes, in accordance with an embodiment. FIG. 2F is a plan view illustration of the glass core with intersecting via planes at a non-orthogonal angle, in accordance with an embodiment. FIG. 3A is a cross-sectional illustration of a glass core with a first surface and a second surface that are exposed by a laser, in accordance with an embodiment. FIG. 3B is a cross-sectional illustration of the glass core with blind via openings into the first surface and the second surface, in accordance with an embodiment. FIG. 3C is a cross-sectional illustration of the glass core with blind vias into the first surface and the second surface, in accordance with an embodiment. FIG. 4A is a cross-sectional illustration of a glass core with a first surface that is exposed by a laser, in accordance with an embodiment. FIG. 4B is a cross-sectional illustration of the glass core with a blind via hole into the first surface, in accordance with an embodiment. FIG. 4C is a cross-sectional illustration of the glass core with a blind via into the first surface, in accordance with an embodiment. FIG. 5A is a cross-sectional illustration of a glass core with a first surface that is exposed by a laser where the morphological change in the glass core extends through an entire thickness of the glass core, in accordance with an embodiment. FIG. 5B is a cross-sectional illustration of the glass core with a via opening extending through the entire thickness of the glass core, in accordance with an embodiment. FIG. 5C is a cross-sectional illustration of the glass core with a via extending through the entire thickness of the glass core, in accordance with an embodiment. FIG. 6A is a perspective view illustration of a glass core with vias and via planes embedded in the glass core, in accordance with an embodiment. FIG. 6B is a perspective view illustration of a glass core with vias and via planes embedded in the glass core where the via planes intersect each other, in accordance with an embodiment. FIG. 7A is a cross-sectional illustration of a package substrate with a glass core with through core vias and buildup layers above and below the glass core, in accordance with an embodiment. FIG. 7B is a cross-sectional illustration of a package substrate with a glass core with through core vias and a buildup layer above the glass core, in accordance with an embodiment. FIG. 7C is a cross-sectional illustration of a package substrate with a core that includes embedded glass core regions and buildup layers above and below the core, in accordance with an embodiment. FIG. 7D is a cross-sectional illustration of a package substrate with a core that includes embedded glass core regions and a buildup layer above the core, in accordance with an embodiment. FIG. 8