Abstract:
A heterostructure contains an IC and an LED. An IC and an LED are initially provided. The IC has at least one first electric-conduction block and at least one first connection block. The IC electrically connects with the first electric-conduction block. The first face of the LED has at least one second electric-conduction block and at least one second connection block. The LED electrically connects to the second electric-conduction block. Subsequently, the first electric-conduction block and the first connection block are respectively joined to the second electric-conduction block and the second connection block. The first electric-conduction block is electrically connected with the second electric-conduction block and forms a heterostructure. The system simultaneously provides functions of heat radiation and electric communication for the IC and LED resulting in a high-density, multifunctional heterostructure.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a heterostructure technology, particularly to a heterostructure containing IC and LED and a method for fabricating the same. 
     2. Description of the Related Art 
     LED (Light Emitting Diode) is a luminescent element, wherein electrons and holes recombine to release light. LEDs made of different materials emit monochromatic lights having different wavelength, which may be categorized into the visible lights and the invisible lights. Compared with the conventional bulb, LED has advantages of high power efficiency, high impact resistance and high blink speed. Therefore, LED has been an indispensable element for daily living. 
     Refer to  FIGS. 1(   a ) to  1 ( c ) sectional views showing conventional steps of fabricating LED with heat-radiating function. In  FIG. 1(   a ), fabricate a LED  12  on a sapphire substrate  10  with a deposition method. Next, in  FIG. 1(   b ), use a metal adhesive layer  14  to join the LED  12  with a high thermal conductivity silicon substrate  16 . Next, in  FIG. 1(   c ), remove the sapphire substrate  10 . The objective of joining the LED  12  with the silicon substrate  16  is to use the high thermal conductivity of the silicon substrate  16  to assist in heat radiation. None electric connection exists between the LED  12  and the silicon substrate  16 . The whole metal adhesive layer  14  is only to mechanically join the LED  12  and the silicon substrate  16 . Thereby, heat generated by the LED  12  is transmitted downward to the silicon substrate  16  and effectively dissipated. The conventional technologies for fabricating LED are mainly high-temperature processes, which have high thermal budget and result in high thermal stress in LED. Besides, the conventional technologies cannot integrate LED with functional IC. 
     Accordingly, the present invention proposes a heterostructure containing IC and LED to overcome the abovementioned problems. 
     SUMMARY OF THE INVENTION 
     The primary objective of the present invention is to provide a heterostructure containing IC and LED and a method for fabricating the same, wherein IC and LED are stacked and joined with a metal and a joining block in a hybrid bonding method, whereby is achieved the heat-radiating function of IC and LED and the electric communication between IC and LED, and whereby is accomplished the development and application of a high-density and multifunctional heterostructure. 
     To achieve the abovementioned objective, the present invention proposes a heterostructure containing IC and LED, which comprises an IC and an LED. The IC has at least one connection structure and at least one electric-conduction structure on the surface thereof, and the IC is electrically connected with the electric-conduction structure. The LED has a first face and a second face opposite to the first face. The first face of the LED is joined to and electrically connected with the electric-conduction structure, whereby the LED is integrated with the IC. Further, the LED may have an electric-conduction through-hole electrically connected with the electric-conduction structure. Besides, the second face of the LED may have an electric-conduction block electrically connected with the electric-conduction through-hole, whereby other structures can be easily stacked on the LED. 
     The present invention also proposes a method for fabricating a heterostructure containing IC and LED, which comprises steps: providing an IC and an LED, wherein the IC has at least one first electric-conduction block and at least one first connection block on the surface thereof, and wherein the IC is electrically connected with the first electric-conduction block, and wherein the LED has a first face and a second face opposite to the first face, and wherein the first face has at least one second electric-conduction block and at least one second connection block, and wherein the LED is electrically connected with the second electric-conduction block; respectively joining the first electric-conduction block and the first connection block to the second electric-conduction block and the second connection block so as to join the IC to the LED, and electrically connecting the first electric-conduction block with the second electric-conduction block, whereby is formed a heterostructure where other structures are easily stacked on the LED. Besides, the LED may further have an electric-conduction through-hole electrically connected with the electric-conduction structure, and the second face has a third electric-conduction block electrically connected with the electric-conduction through-hole. 
     Below, the embodiments are described in detail in cooperation with the drawings to make easily understood the technical contents, characteristic and accomplishments of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1(   a ) to  1 ( c ) are sectional views showing conventional steps for fabricating LED with heat-radiating function; 
         FIG. 2  is a sectional view schematically a heterostructure containing IC and LED according to a first embodiment of the present invention; 
         FIGS. 3(   a ) to  3 ( c ) are sectional views schematically showing steps of fabricating a heterostructure containing IC and LED according to the first embodiment of the present invention; 
         FIG. 3(   d ) is a diagram schematically showing a cutting step according to the first embodiment of the present invention; 
         FIG. 4  is a sectional view schematically a heterostructure containing IC and LED according to a second embodiment of the present invention; 
         FIGS. 5(   a ) to  5 ( d ) are sectional views schematically showing steps of fabricating a heterostructure containing IC and LED according to the second embodiment of the present invention; and 
         FIG. 5(   e ) is a diagram schematically showing a cutting step according to the second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Refer to  FIG. 2  for a heterostructure containing IC and LED according to a first embodiment of the present invention. The present invention comprises an IC (Integrated Circuit)  18  and an LED  24 . The IC  18  has at least one connection structure  20  and at least one electric-conduction structure  22  on the surface thereof. The IC  18  is electrically connected with the electric-conduction structure  22 . The LED  24  has a first face and a second face opposite to the first face. The first face of the LED  24  is on the connection structure  20  and the electric-conduction structure  22  so as to join to the IC  18  and electrically connect with the electric-conduction structure  22 . The IC  18  is a multifunctional one and may function as a power source of the LED  24 , a logic/control processor, a memory, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, an RF (Radio Frequency) IC, etc. Distinct from the conventional technology, the present invention replaces the silicon substrate with an IC. Thereby, the present invention realizes the heat radiation of the IC  18  and the LED  24  and the electric communication between the IC  18  and the LED  24 . Thus is accomplished the development and application of a high-density and multifunctional heterostructure. 
     The connection structure  20  further comprises a first connection block  26  and a second connection block  28 , which may comprise a polymeric material stable below a temperature of 250° C., such as an epoxy-based photoresist SU-8. The first connection block  26  is arranged on the surface of the IC  18 . The second connection block  28  is arranged on the first face of the LED  24  and joined to the first connection block  26 . The electric-conduction structure  22  further comprises a first electric-conduction block and a second electric-conduction block  30 , which comprise a metallic material. The first electric-conduction block is arranged on the surface of the IC  18  and electrically connected with the IC  18 . The second electric-conduction block  30  is arranged on the first face of the LED  24  and electrically connected with the LED  24 . The second electric-conduction block  30  is joined to and electrically connected with the first electric-conduction block. The first electric-conduction block includes a high-temperature metallic connection block  32  disposed on the surface of the IC and a low-temperature metallic connection block  34  joined to and electrically connected with the high-temperature metallic connection block  32  and the second electric-conduction block  30 . The low-temperature metallic connection block  34  may comprise a metallic material stable below a temperature of 250° C., such as tin or indium. In other words, the IC  18  and the LED  24  are joined by a metallic material and a polymeric material in a hybrid bonding way, wherein the metallic material and the polymeric material both function as the joint material but respectively implement electric communication and structural strengthening. Thereby, the present invention not only realizes the electric communication between the IC  18  and the LED  24  but also polymerically fills the micro-gap between the IC  18  and the LED  24 . Thus is improved the bonding strength of the IC  18  and the LED  24  and the reliability of the stacked element. 
     Below is described the method for fabricating the heterostructure containing IC and LED according to the first embodiment of the present invention. Refer to  FIGS. 3(   a ) to  3 ( d ) sectional views schematically showing steps of fabricating the heterostructure containing IC and LED according to the first embodiment of the present invention. Firstly, as shown in  FIG. 3(   a ), form the high-temperature metallic connection block  32  on the surface of the IC  18  and electrically connect the high-temperature metallic connection block  32  with the IC  18 ; form the low-temperature metallic connection block  34  on the high-temperature metallic connection block  32  and electrically connect the low-temperature metallic connection block  34  with the high-temperature metallic connection block  32 , whereby the high-temperature metallic connection block  32  and the low-temperature metallic connection block  34  form the first electric-conduction block  36 . At the same time, form the second electric-conduction block  30  on the first face of the LED  24  and electrically connect the second electric-conduction block  30  with the LED  24 . The high-temperature metallic connection block  32 , the low-temperature metallic connection block  34  and the second electric-conduction block  30  are fabricated with a photolithographic technology, an electroplating technology and an etching technology. Next, as shown in  FIG. 3(   b ), respectively form the first connection block  26  and the second connection block  28  on the surface of the IC  18  and the first face of the LED  24  with a photolithographic technology. A low-temperature process is more suitable to the LED  24 , and the connection material and the electric-conduction material also allow a low-temperature process. Therefore, as shown in  FIG. 3(   c ), process the first and second connection blocks  26  and  28  and the first and second electric-conduction blocks  30  and  36  at a temperature of as low as 25-250° C. to make the first connection block  26  and the low-temperature metallic connection block  34  of the first electric-conduction block  36  respectively join with the second connection block  28  and the second electric-conduction block  30 , whereby is completed the joint of the IC  18  and the LED  24 , and whereby is completed the electric connection of the low-temperature metallic connection block  34  and the second electric-conduction block  30 . Thus is completed a low-temperature joined heterostructure  38 . Next, as shown in  FIG. 3(   d ), perform a cutting process along the dotted line shown in  FIG. 3(   c ) to dice the heterostructure  38  containing the ICs  18  and the LEDs  24  into a plurality of heterostructure units  40 . 
     In the abovementioned steps, the step shown in  FIG. 3(   d ) can be omitted. In  FIG. 3(   a ), the step to form the high-temperature metallic connection block  32  and the low-temperature metallic connection block  34  on the IC  18  can be replaced by a step of directly forming the first electric-conduction block  36  containing the high-temperature and low-temperature metallic connection blocks  32  and  34  on the IC  18 , wherein the high-temperature metallic connection block  32  must be interposed between the low-temperature metallic connection block  34  and the IC  18 . Further, the steps shown in  FIG. 3(   a ) and  FIG. 3(   b ) can be replaced by a single step, wherein is directly provided an IC  18  having at least one first electric-conduction block  36  and at least one first connection block  26  on the surface thereof and electrically connected with the first electric-conduction block  36 , and wherein is directly provided an LED  24  having at least one second electric-conduction block  30  and at least one second connection block  28  on the first face thereof and electrically connected with the second electric-conduction block  30 . The alternative step is also illustrated by  FIG. 3(   b ). Then, undertake the step shown in  FIG. 3(   c ). 
     Below is described a second embodiment of the present invention. Refer to  FIG. 4 . The second embodiment is basically similar to the first embodiment. However, the second embodiment is different from the first embodiment in that the LED  24  has an electric-conduction through-hole  42  electrically connected with the second electric-conduction block  30  of the electric-conduction structure  22  and that at least one third electric-conduction block  44  comprising a metallic material is formed on the second face of the LED  24  and electrically connected with the electric-conduction through-hole  42 . 
     Below is described the method for fabricating the heterostructure containing IC and LED according to the second embodiment of the present invention. Refer to  FIGS. 5(   a ) to  5 ( e ). Firstly, as shown in  FIG. 5(   a ), form the high-temperature metallic connection block  32  on the surface of the IC  18  and electrically connect the high-temperature metallic connection block  32  with the IC  18 ; form the low-temperature metallic connection block  34  on the high-temperature metallic connection block  32  and electrically connect the low-temperature metallic connection block  34  with the high-temperature metallic connection block  32 , whereby the high-temperature metallic connection block  32  and the low-temperature metallic connection block  34  form the first electric-conduction block  36 . At the same time, form the second electric-conduction block  30  on the first face of the LED  24  and electrically connect the second electric-conduction block  30  with the LED  24 . The high-temperature metallic connection block  32 , the low-temperature metallic connection block  34  and the second electric-conduction block  30  are fabricated with a photolithographic technology, an electroplating technology and an etching technology. Next, as shown in  FIG. 5(   b ), firstly form the electric-conduction through-hole  42  in the LED  24  and electrically connect the electric-conduction through-hole  42  with the second electric-conduction block  30 . Next, use a photolithographic technology, an electroplating technology and an etching technology to form the third electric-conduction block  44  on the second face of the LED  24  and electrically connect the third electric-conduction block  44  with the electric-conduction through-hole  42 . Thereby, the LED  24  can be easily installed, and other elements can be easily stacked up. Next, as shown in  FIG. 5(   c ), respectively form the first and second connection blocks  26  and  28  on the surface of the IC  18  and the first face of the LED  24  with a photolithographic technology. Next, similarly to the first embodiment, process the first and second connection blocks  26  and  28  and the first and second electric-conduction blocks  30  and  36  at a temperature of as low as 25-250° C. to make the first connection block  26  and the low-temperature metallic connection block  34  of the first electric-conduction block  36  respectively join with the second connection block  28  and the second electric-conduction block  30 , whereby is completed the joint of the IC  18  and the LED  24 , and whereby is completed the electric connection of the low-temperature metallic connection block  34  and the second electric-conduction block  30 , as shown in  FIG. 5(   d ). Thus is completed a low-temperature joined heterostructure  46 . Next, as shown in  FIG. 5(   e ), perform a cutting process along the dotted line shown in  FIG. 5(   d ) to dice the heterostructure  46  containing the ICs  18  and the LEDs  24  into a plurality of heterostructure units  48 . 
     In the abovementioned steps, the step shown in  FIG. 5(   e ) can be omitted. In  FIG. 5(   a ), the step to form the high-temperature metallic connection block  32  and the low-temperature metallic connection block  34  on the IC  18  can be replaced by a step of directly forming the first electric-conduction block  36  containing the high-temperature and low-temperature metallic connection blocks  32  and  34  on the IC  18 , wherein the high-temperature metallic connection block  32  must be interposed between the low-temperature metallic connection block  34  and the IC  18 . Further, the steps shown in  FIGS. 5(   a )- 5 ( c ) can be replaced by a single step, wherein is directly provided an IC  18  having at least one first electric-conduction block  36  and at least one first connection block  26  on the surface thereof and electrically connected with the first electric-conduction block  36 , and wherein is directly provided an LED  24  having at least one second electric-conduction block  30  and at least one second connection block  28  on the first face thereof and electrically connected with the second electric-conduction block  30 . The alternative step is also illustrated by  FIG. 5(   c ). Then, undertake the step shown in  FIG. 5(   d ). 
     In conclusion, the heterostructure technology of the present invention not only provides a heat-radiation function for IC and LED but also provides an electric-communication function between IC and LED and thus can be used to realize a high-density and multifunctional heterostructure. 
     The embodiments described above are only to exemplify the present invention but not to limit the scope of the present invention. Any equivalent modification or variation according to the structure, characteristic or spirit disclosed in the present invention is to be also included within the scope of the present invention.