Flexible device, flexible pressure sensor, and fabrication method thereof

Abstract

A flexible device, a flexible pressure sensor, and a fabrication method thereof. The present flexible device includes: a first flexible substrate formed of a flexible material to have a flexibility; an active element formed to have a predetermined thickness and a flexibility, and being attached on the first flexible substrate; and a second flexible substrate formed of a flexible material to have a flexibility, and being deposited on the active element. The flexible device and the flexible pressure sensor have a high flexibility, so that they may be applied for a medical treatment such as implantation to a living body, a human body and so forth. In addition, the flexible device has a high flexibility, so that it may be inserted to a curved surface, which contributes to remove the limit of space where the semiconductor package device may be inserted.

1 . A flexible device, comprising: 
 a first flexible substrate formed of a flexible material to have a flexibility;    an active element formed to have a predetermined thickness and a flexibility, and being attached on the first flexible substrate; and    a second flexible substrate formed of a flexible material to have a flexibility, and being deposited on the active element.    
     
     
         2 . The flexible device as claimed in  claim 1 , wherein the active element comprises at least one of a logic integrated circuit (IC), a central processing unit (CPU), a memory, a digital signal processor (DSP), a sensor, an actuator, and a communication device.  
     
     
         3 . The flexible device as claimed in  claim 1 , wherein a thickness of the active element is 50 μm or less.  
     
     
         4 . The flexible device as claimed in  claim 1 , further comprising: 
 another active element formed to have a predetermined thickness and a flexibility, and being attached below the first flexible substrate.    
     
     
         5 . The flexible device as claimed in  claim 1 , further comprising: 
 a passive element formed in the first flexible substrate.    
     
     
         6 . The flexible device as claimed in  claim 5 , wherein the passive element comprises at least one of a resistor, an inductor, and a capacitor.  
     
     
         7 . The flexible device as claimed in  claim 1 , wherein the first and second flexible substrates are formed of a flexible high molecular material.  
     
     
         8 . The flexible device as claimed in  claim 7 , wherein the high molecular material is polyimide.  
     
     
         9 . A method of fabricating a flexible device, comprising: 
 a) preparing an active element formed to have a predetermined thickness and a flexibility;    b) attaching the active element on a first flexible substrate formed of a flexible material to have a flexibility; and    c) depositing, on the active element, a second flexible substrate formed of a flexible material to have a flexibility.    
     
     
         10 . The method as claimed in  claim 9 , wherein the a) step includes: 
 a1) forming a plurality of the active elements with the predetermined thickness on one region of a wafer;    a2) etching regions between the active elements by the predetermined thickness;    a3) attaching a tape to the active elements;    a4) attaching a substrate to the tape;    a5) polishing a region other than the one region of the wafer; and    a6) preparing the active element by removing any one of the active elements attached to the tape from the tape.    
     
     
         11 . The method as claimed in  claim 10 , wherein the a2) step comprises wet etching on the regions between the active elements.  
     
     
         12 . The method as claimed in  claim 10 , wherein the a5) step comprises performing chemical polishing on the region other than the one region.  
     
     
         13 . The method as claimed in  claim 10 , wherein the predetermined thickness of the active element is 50 μm or less.  
     
     
         14 . The method as claimed in  claim 9 , wherein the b) step comprises attaching the active element on the first flexible substrate using at least one of thermo-compression bonding and adhesive bonding methods.  
     
     
         15 . The method as claimed in  claim 9 , further comprising: 
 attaching another active element formed with a predetermined thickness to have a flexibility, below the first flexible substrate.    
     
     
         16 . The method as claimed in  claim 9 , further comprising: 
 forming a passive element in the first flexible substrate.    
     
     
         17 . A flexible pressure sensor, comprising: 
 a flexible substrate formed of a flexible material to have a flexibility, and allowing a circular shape to be formed when it is bent;    a first electrode formed in one surface of the flexible substrate;    a second electrode formed in the one surface of the flexible substrate, and facing the first electrode to form a capacitor when the flexible substrate is formed to have the circular shape; and    a coil formed in the other surface of the flexible substrate, and forming a resonance circuit electrically connected to a capacitor formed by the first and second electrodes, and outputting a signal corresponding to a resonance frequency which changes in response to a change of a capacitance between the first electrode and the second electrode.    
     
     
         18 . The flexible pressure sensor as claimed in  claim 17 , wherein the capacitance between the first electrode and the second electrode changes in response to a change of a diameter of a material interposed between the first electrode and the second electrode.  
     
     
         19 . The flexible pressure sensor as claimed in  claim 18 , wherein the interposed material is a blood vessel.  
     
     
         20 . The flexible pressure sensor as claimed in  claim 17 , further comprising: 
 another flexible substrate formed of a flexible material to have a flexibility, allowing a circular shape to be formed when it is bent, and being deposited on the coil.    
     
     
         21 . The flexible pressure sensor as claimed in  claim 17 , wherein the flexible substrate is formed of a flexible high molecular material.  
     
     
         22 . The flexible pressure sensor as claimed in  claim 21 , wherein the high molecular material is polyimide.  
     
     
         23 . The flexible pressure sensor as claimed in  claim 17 , wherein the first and second electrodes are formed of gold (Au).  
     
     
         24 . The flexible pressure sensor as claimed in  claim 17 , wherein the coil is formed of copper (Cu).  
     
     
         25 . A method of fabricating a flexible pressure sensor, comprising: 
 forming a first electrode in one surface of a flexible substrate, the flexible substrate being formed of a flexible material to have a flexibility and allowing a circular shape to be formed when it is bent;    forming a second electrode formed in the one surface of the flexible substrate, and facing the first electrode to form a capacitor when the flexible substrate is formed to have the circular shape; and    forming a coil in the other surface of the flexible substrate, the coil forming a resonance circuit electrically connected to a capacitor formed by the first and second electrodes and outputting a signal corresponding to a resonance frequency which changes in response to a change of a capacitance between the first electrode and the second electrode.    
     
     
         26 . The method as claimed in  claim 25 , further comprising: 
 depositing another flexible substrate on the coil, the another flexible substrate being formed of a flexible material to have a flexibility and allowing a circular shape to be formed when it is bent.