CN-121986550-A - Ultra-thin composite dielectric for printed circuit boards

Abstract

A layer of dielectric material is provided that includes a thermoplastic Liquid Crystal Polymer (LCP) substrate coated or impregnated with a thermosetting resin. The dielectric material layer may have a dielectric constant (DK) value of less than about 3.4 and a loss tangent of less than about 0.005 for use in a printed circuit board. The dielectric material layer may have particular utility in High Density Interconnect (HDI) printed circuit boards.

Inventors

• T. Amra
• K. Amra
• J. Amra

Assignees

• 先进芯片电路材料股份有限公司

Dates

Publication Date

20260505

Application Date

20240730

Priority Date

20230731

Claims (20)

1. 1. A printed circuit board, comprising: at least one layer of dielectric material comprising a thermoplastic Liquid Crystal Polymer (LCP) substrate coated or impregnated with a thermosetting resin.
2. 2. The printed circuit board of claim 1, wherein the at least one layer of dielectric material has a dielectric constant (DK) value of less than about 3.4.
3. 3. The printed circuit board of claim 2, wherein the at least one layer of dielectric material has a DK value less than about 3.0.
4. 4. The printed circuit board of claim 3, wherein the at least one layer of dielectric material has a DK value less than about 2.8.
5. 5. The printed circuit board of claim 1, wherein the at least one layer of dielectric material is characterized by a loss tangent of less than about 0.005.
6. 6. The printed circuit board of claim 5, wherein the at least one layer of dielectric material is characterized by a loss tangent of less than about 0.0025.
7. 7. The printed circuit board of claim 1, wherein the at least one layer of dielectric material has a thickness of less than about 100 microns.
8. 8. The printed circuit board of claim 7, wherein the at least one layer of dielectric material has a thickness of less than about 50 microns.
9. 9. The printed circuit board of claim 8, wherein the at least one layer of dielectric material has a thickness of less than about 40 microns.
10. 10. The printed circuit board of claim 9, wherein the at least one layer of dielectric material has a thickness of less than about 25 microns.
11. 11. The printed circuit board of claim 1, wherein the at least one layer of dielectric material comprises a prepreg or laminate.
12. 12. The printed circuit board of claim 1, wherein the thermosetting resin is a crosslinked thermosetting polymer resin selected from the group consisting of epoxy resin, bismaleimide resin, cyanate resin, BT resin, polybutadiene resin, and PPE/PPO resin.
13. 13. The printed circuit board of claim 1, wherein the thermosetting resin is a crosslinked thermosetting polymer resin comprising at least one resin selected from the group consisting of vinyl functional PPE resin, OPE resin, bismaleimide resin, triallyl cyanurate resin, and triallyl isocyanurate resin.
14. 14. The printed circuit board of claim 1, wherein the thermosetting resin is substantially halogen-free.
15. 15. The printed circuit board of claim 13, wherein the thermosetting resin further comprises at least one of a flame retardant, a curing agent, a hardener, a filler, and an additive.
16. 16. The printed circuit board of claim 1, wherein the at least one layer of dielectric material is copper clad.
17. 17. The printed circuit board of claim 1, wherein the LCP substrate comprises a polyarylate resin.
18. 18. The printed circuit board of claim 1, wherein the LCP substrate is characterized by a basis weight of less than about 25 GSM.
19. 19. A printed circuit board according to claim 18, wherein the LCP substrate is characterized by a basis weight of less than about 10 GSM.
20. 20. The printed circuit board of claim 1, wherein the at least one layer of dielectric material is characterized by a glass transition temperature (Tg) greater than about 150 ℃.

Description

Ultra-thin composite dielectric for printed circuit boards Technical Field Aspects relate generally to printed circuit boards, including High Density Interconnect (HDI) printed circuit boards, and more particularly to dielectrics used therein. Background Next generation products related to chip package substrates, mobile devices, and communication technologies such as 5G require thinner dielectrics. These thin dielectrics also need to have a low loss tangent and low dielectric constant to improve signal integrity. In addition to thickness requirements, dielectric materials also need to be easy to laser drill. In current advanced technology, glass reinforced materials are typically used, but these materials create laser drilling problems because glass requires more energy to ablate than polymeric resins, which results in poor hole quality. In addition, glass reinforcement is also limited in its ability to produce extremely thin dielectrics. Disclosure of Invention According to one or more aspects, a printed circuit board is disclosed. The printed circuit board may comprise at least one layer of dielectric material comprising a thermoplastic Liquid Crystal Polymer (LCP) substrate coated or impregnated with a thermosetting resin. In some aspects, the at least one layer of dielectric material may have a dielectric constant (DK) value less than about 3.4. The at least one layer of dielectric material may have a DK value less than about 3.0. The at least one layer of dielectric material may have a DK value less than about 2.8. In some aspects, the at least one layer of dielectric material may be characterized by a loss tangent of less than about 0.005. The at least one layer of dielectric material may be characterized by a loss tangent of less than about 0.0025. In some aspects, the at least one layer of dielectric material may have a thickness of less than about 125 microns. The at least one layer of dielectric material may have a thickness of less than about 50 microns. The at least one layer of dielectric material may have a thickness of less than about 40 microns. The at least one layer of dielectric material may have a thickness of less than about 25 microns. In some aspects, the at least one layer of dielectric material may comprise a prepreg or laminate. In some aspects, the thermosetting resin may be a crosslinked thermosetting polymer resin selected from the group consisting of epoxy resins, bismaleimide resins, cyanate resins, BT resins, polybutadiene resins, and PPE/PPO resins. The thermosetting resin may be a crosslinked thermosetting polymer resin comprising at least one resin selected from the group consisting of vinyl functional PPE resin, OPE resin, bismaleimide resin, triallyl cyanurate resin, and triallyl isocyanurate resin. In at least some non-limiting aspects, the thermosetting resin may be substantially halogen-free. In some aspects, the thermosetting resin may further comprise at least one of a flame retardant, a curing agent, a hardener, a filler, and an additive. In some aspects, at least one layer of dielectric material may be copper coated. In some aspects, the LCP substrate may include a polyarylate resin. In some aspects, the LCP substrate may be characterized by a basis weight of less than about 25 GSM. The LCP substrate may be characterized by a basis weight of less than about 10 GSM. In some aspects, the at least one layer of dielectric material may be characterized by a glass transition temperature (Tg) greater than about 150 ℃. In some aspects, the at least one layer of dielectric material may be characterized by a tensile modulus in the in-plane direction of greater than about 5 GPa. In some aspects, the printed circuit board may be a High Density Interconnect (HDI) printed circuit board. Described herein are Liquid Crystal Polymer (LCP) substrate reinforced dielectric material layers with thermoset polymeric matrices for use in printed circuit boards and High Density Interconnect (HDI) printed circuit boards. LCPs are thermoplastics and the use of thermoplastics in multilayer printed circuit boards is limited to double sided applications, mainly because these materials melt above 290 ℃. Multi-layer boards including HDI boards need to undergo multiple pressing or lamination cycles. Because LCP materials melt at such high temperatures, this is not feasible in most Printed Circuit Board (PCB) workshops. In addition, reliability may be adversely affected when at such high temperatures. In high density interconnect fabrication, vias are fabricated in each layer and exposure to high temperatures (i.e., greater than about 260 ℃) will accelerate via failure. In the present invention, these problems are solved by using an LCP substrate as a reinforcement, which is impregnated or coated with a thermosetting resin and cured to B-stage, so it can then be used to form copper clad laminates or non-clad laminates and prepregs for use in printed circuit boards. One aspect of the present invent