CN-122028740-A - Signal transmission element

CN122028740ACN 122028740 ACN122028740 ACN 122028740ACN-122028740-A

Abstract

The invention provides a signal transmission element which does not need a step of leading out a lower layer coil to the surface of the element. The signal transmission element includes a first insulating layer on a semiconductor substrate, a first coil and a second coil on the first insulating layer, a second insulating layer covering the first coil and the second coil, a third coil and a fourth coil on the second insulating layer, and a protective film covering the third coil and the fourth coil, wherein the first coil and the third coil are magnetically coupled, the second coil and the fourth coil are magnetically coupled, and the first coil and the second coil are connected to each other so that a current generated by mutual induction between the first coil and the third coil flows to the second coil, and the protective film has a plurality of openings reaching both ends of the third coil and both ends of the fourth coil.

Inventors

Ji Yexue
SHITOMI TAKUICHIRO

Assignees

三菱电机株式会社

Dates

Publication Date: 20260512
Application Date: 20250905
Priority Date: 20241111

Claims (8)

1. A signal transmission element, comprising: A first insulating layer disposed on the semiconductor substrate; a first coil and a second coil disposed adjacent to each other on the first insulating layer; A second insulating layer provided on the first insulating layer and covering the first coil and the second coil; a third coil and a fourth coil disposed adjacent to each other on the second insulating layer, and An insulating protective film provided on the second insulating layer and covering the third coil and the fourth coil, The first coil is magnetically coupled to the third coil, The second coil is magnetically coupled to the fourth coil, The first coil and the second coil are connected to each other such that an electric current generated by mutual induction between the first coil and the third coil flows to the second coil, The protective film has a plurality of opening portions reaching both end portions of the third coil and both end portions of the fourth coil.
2. The signal transmission element of claim 1, wherein the signal transmission element comprises a plurality of signal transmission elements, The winding direction of the first coil is opposite to that of the second coil, the central end of the first coil is electrically connected with the outer peripheral end of the second coil, An outer peripheral end of the first coil is electrically connected to a central end of the second coil.
3. The signal transmission element of claim 1, wherein the signal transmission element comprises a plurality of signal transmission elements, The winding direction of the first coil is the same as that of the second coil, the central end of the first coil is electrically connected with the central end of the second coil, An outer peripheral end of the first coil is connected to an outer peripheral end of the second coil.
4. The signal transmission element according to any one of claim 1 to 3, wherein, The thickness of the second insulating layer is set to be half of the thickness required for insulation and voltage resistance between the first and second coils and the third and fourth coils.
5. A signal transmission element, comprising: a first block and a second block, The first block includes: A first insulating layer disposed on the semiconductor substrate; a first coil and a second coil disposed adjacent to each other on the first insulating layer; A second insulating layer provided on the first insulating layer and covering the first coil and the second coil; a third coil and a fourth coil disposed adjacent to each other on the second insulating layer; a third insulating layer provided on the second insulating layer and covering the third coil and the fourth coil; a plurality of wiring layers disposed on the third insulating layer, and An insulating protective film provided on the third insulating layer and covering the plurality of wiring layers, Wherein, the The first coil is magnetically coupled to the third coil, The second coil is magnetically coupled to the fourth coil, Connecting the first coil and the second coil to each other in such a manner that an electric current generated by mutual induction between the first coil and the third coil flows to the second coil, The second block has the same structure as the first block, The first block and the second block are arranged in a continuous manner in a top view, Interconnecting said fourth coil of said first block and said third coil of said second block in such a way that an electric current flowing through said fourth coil of said first block flows towards said third coil of said second block, The protective film has a plurality of opening portions reaching both ends of the third coil of the first block and both ends of the fourth coil of the second block.
6. The signal transmission element of claim 5, wherein the signal transmission element comprises a plurality of signal transmission elements, The fourth coil of the first block and the third coil of the second block are wound in opposite directions, a center portion end of the fourth coil of the first block is electrically connected to an outer peripheral portion end of the third coil of the second block, An outer peripheral end of the fourth coil of the first block is electrically connected to a central end of the third coil of the second block.
7. The signal transmission element of claim 5, wherein the signal transmission element comprises a plurality of signal transmission elements, The semiconductor substrate is an SOI substrate, and has: A silicon substrate; a buried insulating layer disposed on the silicon substrate, and A semiconductor layer disposed on the buried insulating layer, The semiconductor layer has a separate insulating layer provided so as to reach the buried insulating layer at a portion corresponding to between the first block and the second block in a plan view.
8. The signal transmission element of claim 5, wherein the signal transmission element comprises a plurality of signal transmission elements, The winding direction of the fourth coil of the first block is the same as that of the third coil of the second block, a center end of the fourth coil of the first block is connected with a center end of the third coil of the second block, An outer peripheral end of the fourth coil of the first block is connected to an outer peripheral end of the third coil of the second block.

Description

Signal transmission element Technical Field The present disclosure relates to signal transmission elements, and more particularly to insulated signal transmission elements. Background An insulating signal transmission element (transmission element) is an element that transmits a signal in a state of being electrically and physically insulated between an input and an output. For example, in a gate driver of a power chip, a microcomputer for control is connected to an input side, a gate of the power chip is connected to an output side, and a signal of the microcomputer is transmitted to the power chip. In an insulating signal transmission element in which magnetic coupling is formed in a direction perpendicular to a semiconductor substrate, for example, as shown in fig. 21 of patent document 1, it is necessary to etch a thick insulating layer between an upper coil and a lower coil in order to draw out an electrode of the lower coil close to the semiconductor substrate to the element surface. Patent document 1 Japanese patent laid-open No. 2023-124329 In patent document 1, since it is necessary to etch a thick insulating layer between an upper layer coil and a lower layer coil in order to draw out the lower layer coil to the element surface, there is a problem that the processing load in the wafer process becomes high. Disclosure of Invention The present disclosure has been made to solve the above-described problems, and an object of the present disclosure is to provide a signal transmission element that does not require a step of drawing a lower-layer coil to the element surface. The signal transmission element includes a first insulating layer provided on a semiconductor substrate, a first coil and a second coil provided adjacent to each other on the first insulating layer, a second insulating layer provided on the first insulating layer and covering the first coil and the second coil, a third coil and a fourth coil provided adjacent to each other on the second insulating layer, and an insulating protective film provided on the second insulating layer and covering the third coil and the fourth coil, the first coil being magnetically coupled to the third coil, the second coil being magnetically coupled to the fourth coil, and the first coil and the second coil being connected to each other so that a current generated by mutual induction between the first coil and the third coil flows to the second coil, the protective film having a plurality of openings reaching both ends of the third coil and both ends of the fourth coil. According to the signal transmission element of the present disclosure, the third coil on the input side and the fourth coil on the output side are both disposed on the second insulating layer, and therefore the second insulating layer is not removed even if the thickness of the second insulating layer becomes thick, and the electrodes on the input side and the output side can be obtained only by removing the protective film, and therefore the signal transmission element that does not require a process of drawing out the lower layer coil to the element surface can be obtained. Drawings Fig. 1 is a cross-sectional view showing the structure of a signal transmission element according to embodiment 1. Fig. 2 is a plan view schematically showing a planar structure of a metal wiring layer on a lower layer side of the signal transmission element of embodiment 1. Fig. 3 is a plan view schematically showing the planar structure of the metal wiring layer on the upper layer side of the signal transmission element of embodiment 1. Fig. 4 is a plan view schematically showing a planar structure of a modified example of a metal wiring layer on the lower layer side of the signal transmission element according to embodiment 1. Fig. 5 is a cross-sectional view showing a configuration of a modification of the signal transmission element of embodiment 1. Fig. 6 is a cross-sectional view showing the structure of a signal transmission element according to embodiment 2. Fig. 7 is a plan view schematically showing a planar structure of a metal wiring layer on a lower layer side of the signal transmission element of embodiment 2. Fig. 8 is a plan view schematically showing a planar structure of a metal wiring layer on an upper layer side of the signal transmission element of embodiment 2. Fig. 9 is a plan view schematically showing the planar structure of the metal wiring layer of the uppermost layer of the signal transmission element according to embodiment 2. Fig. 10 is a cross-sectional view showing a configuration of a modification of the signal transmission element according to embodiment 2. Fig. 11 is a plan view schematically showing a planar structure of a modification of the metal wiring layer on the upper layer side of the signal transmission element according to embodiment 2. Detailed Description < Embodiment 1> < Device Structure > Fig. 1 is a cross-sectional view showing the structure of a signal tran