Filter with cover layer and shield layer

Patent metadata

Field	Value
Publication number	US-12127384-B2
Application number	US-202117307015-A
Country	US
Kind code	B2
Filing date	May 4, 2021
Priority date	May 13, 2020
Publication date	Oct 22, 2024
Grant date	Oct 22, 2024

Abstract

A filter can include a monolithic substrate and at least one conductive layer formed over a top surface of the monolithic substrate and along at least a portion of one or more of a first top edge of the monolithic substrate or a second top edge of the monolithic substrate. A cover layer can be arranged over the top surface of the monolithic substrate. A shield layer can connect with one or more of the conductive layer(s) at the first top edge or the second top edge of the monolithic substrate. The shield layer can include a first portion formed over the first side surface of the cover layer, a second portion formed over the top surface of the cover layer, and a third portion formed over the second side surface of the cover layer.

First claim

What is claimed is:

1. A filter comprising:
a monolithic substrate having a top surface, a first side surface perpendicular to the top surface, a second side surface perpendicular to the top surface, a first top edge along an intersection between the top surface and the first side surface, and a second top edge opposite the first top edge and along an intersection between the top surface and the second side surface;
at least one conductive layer formed over the top surface of the monolithic substrate and along at least a portion of one or more of the first top edge of the monolithic substrate or the second top edge of the monolithic substrate;
a cover layer arranged over the top surface of the monolithic substrate, the cover layer having a top surface parallel with the top surface of the monolithic substrate, the cover layer having a first side surface and a second side surface opposite the first side surface, and wherein the first side surface of the cover layer is parallel with the first side surface of the monolithic substrate, and the second side surface of the cover layer is parallel with the second side surface of the monolithic substrate; and
a shield layer that connects with one or more of the at least one conductive layer at one or more of the first top edge or the second top edge of the monolithic substrate, and wherein the shield layer comprises a first portion formed over the first side surface of the cover layer, a second portion formed over the top surface of the cover layer, and a third portion formed over the second side surface of the cover layer.

2. The filter of claim 1 , wherein the first side surface of the cover layer is coplanar with the first side surface of the monolithic substrate, and the second side surface of the cover layer is coplanar with the second side surface of the monolithic substrate.

3. The filter of claim 1 , wherein:
the first portion of the shield layer is also formed over the first side surface of the monolithic substrate; and
the third portion of the shield layer is also formed over the second side surface of the monolithic substrate.

4. The filter of claim 1 , wherein the monolithic substrate has a bottom surface that is opposite the top surface of the monolithic substrate, and wherein the shield layer comprises a fourth portion formed over the bottom surface of the monolithic substrate.

5. The filter of claim 1 , wherein:
the monolithic substrate includes a bottom surface that is opposite the top surface of the monolithic substrate, a first bottom edge at an intersection of the bottom surface of the monolithic substrate and the first side surface of the monolithic substrate, and a second bottom edge at an intersection of the bottom surface of the monolithic substrate and the second side surface of the monolithic substrate; and
the shield layer comprises a fourth portion formed over the bottom surface of the monolithic substrate and along at least a portion of the first bottom edge of the monolithic substrate, and a fifth portion formed over the bottom surface of the monolithic substrate and along at least a portion of the second bottom edge of the monolithic substrate.

6. The filter of claim 1 , wherein the cover layer has a thickness direction that is perpendicular to the top surface of the monolithic substrate, and wherein the thickness of the cover layer ranges from about 250 μm to about 3,000 μm.

7. The filter of claim 1 , wherein the filter exhibits an insertion loss response having a band pass frequency range that has a lower bound that is greater than 10 GHz and an upper bound that is greater than the lower limit by less than about 10 GHz.

8. The filter of claim 1 , wherein the filter exhibits an insertion loss response having a band pass frequency range that that has a lower bound, an upper bound, and a rate of decrease from at least one of the lower bound or the upper that is greater than about 10 dB per GHz.

9. The filter of claim 1 , wherein the at least one conductive layer comprises a first conductive layer and a second conductive layer, the shield layer connecting with the first conductive layer at the first top edge of the monolithic substrate,
the shield layer connecting with the second conductive layer at the second top edge of the monolithic substrate.

10. The filter of claim 1 , wherein the at least one conductive layer comprises a first conductive layer comprising a first plurality of resonator arms and a second conductive layer comprising a second plurality of resonator arms interdigitated with the first plurality of resonator arms of the first conductive layer.

11. A method of forming a filter, the method comprising:
providing a monolithic substrate having a top surface, a first side surface perpendicular to the top surface, a second side surface perpendicular to the top surface, a first top edge along an intersection between the top surface and the first side surface, and a second top edge opposite the first top edge and along an intersection between the top surface and the second side surface;
forming at least one conductive layer over the top surface of the monolithic substrate and along at least a portion of one or more of the first top edge of the monolithic substrate or the second top edge of the monolithic substrate;
arranging a cover layer over the top surface of the monolithic substrate, the cover layer having a top surface parallel with the top surface of the monolithic substrate, the cover layer having a first side surface and a second side surface opposite the first side surface, and wherein the first side surface of the cover layer is parallel with the first side surface of the monolithic substrate, and the second side surface of the cover layer is parallel with the second side surface of the monolithic substrate; and
forming a shield layer that connects with one or more of the at least one conductive layer at one or more of the first top edge or the second top edge of the monolithic substrate, and wherein the shield layer comprises a first portion formed over the first side surface of the cover layer, a second portion formed over the top surface of the cover layer, and a third portion formed over the second side surface of the cover layer.

12. The method of claim 11 , wherein forming the shield layer comprises:
forming the first portion of the shield layer over the first side surface of the monolithic substrate; and
forming the second portion of the shield layer over the second side surface of the monolithic substrate.

13. The method of claim 11 , wherein forming the shield layer comprises forming a fourth portion of the shield layer over a bottom surface of the monolithic substrate, the bottom surface opposite the top surface of the monolithic substrate.

14. The method of claim 11 , wherein forming the shield layer comprises:
forming a fourth portion of the shield layer over a bottom surface of the monolithic substrate and along at least a portion of a first bottom edge of the monolithic substrate that is between the bottom surface of the monolithic substrate and the first side surface of the monolithic substrate; and
forming a fifth portion of the shield layer over the bottom surface of the monolithic substrate and along at least a portion of a second bottom edge of the monolithic substrate that is between the bottom surface of the monolithic substrate and the second side surface of the monolithic substrate.

15. The method of claim 11 , wherein forming the at least one conductive layer comprises:
forming a first conductive layer over the top surface of the monolithic substrate, the first conductive layer connecting with the

Assignees

• Avx Corp
• Kyocera Avx Components Corp

Inventors

• Nelson Cory
• Korony Gheorghe

Classifications

• H03H9/56

  Monolithic crystal filters · CPC title

• H03H9/562

  comprising a ceramic piezoelectric layer · CPC title

• H05K9/0081 Primary

  Electromagnetic shielding materials, e.g. EMI, RFI shielding (H05K9/0003 takes precedence) · CPC title

• H05K9/0066 Primary

  Constructional details of transient suppressor · CPC title