BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view illustrating a bonding structure of panel and back-plate in accordance with an embodiment of the present invention.
FIG. 2
a is a top view diagram illustrating a back surface of silicon wafer in LCoS panel in accordance with an embodiment of the present invention.
FIG. 2
b is a top view diagram illustrating a coarse structure of the back surface of silicon wafer in LCoS panel in accordance with FIG. 2a.
FIG. 3 is a top view diagram illustrating a coarse structure of the back surface of one die in LCoS panel of FIG. 2b in accordance with an embodiment of the present invention.
FIG. 4 is a cross-sectional view diagram illustrating a coarse structure on the back surface of silicon wafer in accordance with an embodiment of the present invention.
FIG. 5 is a cross-sectional view diagram illustrating a coarse structure on the back surface of silicon wafer in accordance with an embodiment of the present invention.
FIG. 6 is a cross-sectional view diagram illustrating a coarse structure on the back surface of silicon wafer in accordance with an embodiment of the present invention.
FIG. 7 is an explored sectional view illustrating a bonding structure of panel and back-plate with a back-plate module according to one embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates a bonding structure of panel and back-plate in accordance with an embodiment of the present invention. The LCoS panel has one glass layer 12 and one silicon layer 14 on both sides respectively. After the back-plate module 16 is glued to the back surface of the silicon layer 14 to complete the seal work, and liquid crystals 13 are filled between the glass layer 12 and the silicon layer 14. Thus, the die bond process is complete.
FIG. 2
a is a top view diagram illustrating a back surface of silicon wafer in LCoS panel in accordance with an embodiment of the present invention. The silicon wafer 20 is a substrate used in LCoS panel, and the back surface of the silicon wafer 20 has a grid of trenches 21 about 500 μm deep for cutting the silicon wafer 20 to many separate dies.
FIG. 2
b is a top view diagram illustrating a coarse structure of the back surface of silicon wafer in LCoS panel in accordance with FIG. 2a. A coarse structure, a grid of trenches 21′ cutting the silicon wafer, and a grid of indented lines 22 are on the back surface of the silicon wafer 20′. The indented lines 22 are made by laser cutting about 100 μm to 200 μm in depth to form a coarse surface on the back surface of silicon wafer 20′, thus when the back-plate module (not shown) is bonded to the LCoS panel, the bonding strength between them will be enhanced by those dies to prevent position shift. Additionally, the grid of trenches 21′ may have different patterns on the back surface of the silicon wafer 20′, for example, the indented lines 22 cross the grid of trenches 21′ with an oblique angle.
FIG. 3 is a top view diagram illustrating a coarse structure of the back surface of one die in LCoS panel of FIG. 2b in accordance with an embodiment of the present invention. After the silicon wafer is cut across the trenches, the indented lines 22′ forms a coarse structure on a single die 25.
FIG. 4 is a cross-sectional view diagram illustrating a coarse structure on the back surface of silicon wafer in accordance with an embodiment of the present invention. The coarse structure is an indentation 31 on the back surface of silicon wafer 30. In addition, the indentation 31 may be a recess grinded by a grinder using the abrasive solvent with 100 μm to 200 μm diameter.
Furthermore, the coarse structure on the back surface of the silicon wafer is higher than the back surface of the silicon wafer. The coarse structure is some non-metal particles 41 sprayed on the back surface 42 of the silicon wafer 40 illustrated in FIG. 5. In another embodiment, the coarse structure may be a polymer solvent 51 inject-printed on the back surface 52 of the silicon wafer 50 with a given pattern illustrated in FIG. 6.
The coarse structure may be some photo-resist spread on the back surface by using photolithography. The coarse structure also could be the polymer solvent printed on the back surface with a specific pattern by using screen-printing.
FIG. 7 illustrates a bonding structure of a panel and a back-plate module according to one embodiment of the present invention. The bonding structure is a component of a projector and the bonding structure includes a LCoS panel including a glass layer 62, a silicon layer 64, and liquid crystals 63 filled between the glass layer 62 and the silicon layer 64, wherein the back surface of the silicon layer 64 has a plurality of lower indentations 67 configured on the back surface of the silicon layer 64, and a back-plate module 66 having some bosses 68 disposed on its surface bonded to the back surface of said silicon layer 64, wherein the bosses 68 matches with the indentation 67 for precisely positioning the LCoS panel on the surface of the back-plate module 66.
Accordingly, those dies are produced by cutting the wafer across the trenches. And the indented lines form a coarse surface on the back of die in FIG. 3.
Accordingly, the coarse structure on the back surface of wafer gets a more contact area than that a smooth surface does. As a result, the strength of die bond between the LCoS panel and the back-plate module will be enhanced to solve the position shift problem in sequential processes. Consequently, the rework process of bonding the LCoS panel to the back-plate module can be avoided; sometimes the rework process may damage the LCoS panel wiring, rise up the cost and waste the labor effort.
Although the present invention has been explained in relation to its preferred embodiment, it is to be understood that other modifications and variation can be made without departing the spirit and scope of the invention as hereafter claimed.
Patent Application
20080055533
