一种QFN芯片封装结构

Abstract

本实用新型公开了一种QFN芯片封装结构，包括：底部基板、感光芯片、密封胶圈、滤光玻璃和填充胶圈；底部基板为铜箔基板阵列中的一个封装区域，基板阵列包含多个阵列排布的封装区域，相邻封装区域之间设有裁切线，封装区域的边缘位置形成有多个电连接焊盘，底部基板中部设有填充腔，填充腔内填充有固化导热绝缘材料；感光芯片固定设置于底部基板的上表面；密封胶圈设置于感光芯片的感光区域的外周边缘上方；滤光玻璃覆盖设置于密封胶圈的上方；填充胶圈环绕设置于感光芯片、密封胶圈和滤光玻璃的外周，并将感光芯片、滤光玻璃、密封胶圈与底部基板固定连接。本实用新型同步提升热导率、结构完整性和批量制造适应性。

Claims

1. A QFN chip package structure, characterized in that, include: Bottom substrate (1), photosensitive chip (2), sealing ring (3), filter glass (4), and filling ring (5); The bottom substrate (1) is a packaging area in a copper foil substrate array. The substrate array includes multiple packaging areas arranged in an array. Cutting lines are provided between adjacent packaging areas. Multiple electrical connection pads (6) are formed at the edge of the packaging area. A filling cavity (16) is provided in the middle of the bottom substrate (1). The filling cavity (16) is filled with a cured thermally conductive insulating material. The photosensitive chip (2) is fixedly disposed on the upper surface of the bottom substrate (1); The sealing ring (3) is disposed above the outer peripheral edge of the photosensitive area of ​​the photosensitive chip (2); The filter glass (4) is disposed above the sealing ring (3); The filling rubber ring (5) is disposed around the outer periphery of the photosensitive chip (2), the sealing rubber ring (3) and the filter glass (4), and fixes the photosensitive chip (2), the filter glass (4), the sealing rubber ring (3) to the bottom substrate (1).

2. The QFN chip package structure of claim 1, wherein: The filling cavity (16) is provided with a pre-formed microchannel network (8), which includes interconnected serpentine or mesh-like grooves; both ends of the microchannel network (8) extend to the side edges of the bottom substrate (1) to form a cooling medium inlet and outlet; the cured thermally conductive insulating material fills the cavity space outside the microchannel network (8).

3. The QFN chip package structure of claim 2, wherein: The cross-section of the microchannel network (8) is rectangular or trapezoidal, with a depth of 50-200μm and a width of 100-500μm; After the cured thermally conductive insulating material is filled into the filling cavity (16), it comes into close contact with the microchannel network (8) to form a solid-fluid dual-phase composite cooling channel.

4. The QFN chip package structure of claim 1, wherein: An annular elastic support layer (9) is provided between the photosensitive chip (2) and the bottom substrate (1). The upper surface of the elastic support layer (9) is fixed to the bottom surface of the non-functional area of ​​the photosensitive chip (2), and the lower surface is fixed to the upper surface of the bottom substrate (1). The solidified thermally conductive insulating material in the filling cavity (16) protrudes upward to form a thermally conductive boss (10), and a gap of 10-50μm is provided between the top surface of the thermally conductive boss (10) and the bottom surface of the functional area of ​​the photosensitive chip (2).

5. The QFN chip package structure of claim 4, wherein: The thickness of the elastic support layer (9) is 0.2-0.5 mm; The thermally conductive boss (10) is integrally formed from the cured thermally conductive insulating material, and its top flatness deviation is ≤5μm.

6. The QFN chip packaging structure according to claim 1, characterized in that: The upper surface edge of the bottom substrate (1) is provided with an annular stepped groove (11), the annular stepped groove (11) comprising: The inner annular shallow groove (111) has a depth of 0.1-0.3 mm and a width that covers the inner edge of the pad to the mounting area of ​​the filler ring (5); The outer annular deep groove (112) has a depth of 0.5-1.0 mm, and a metal shielding ring (12) is embedded in the groove; The filling rubber ring (5) fills and covers the annular stepped groove (11) to form a mechanical interlocking structure.

7. The QFN chip package structure of claim 6, wherein: The top of the metal shielding ring (12) is 0.05-0.15 mm lower than the upper surface of the bottom substrate (1); The lower part of the filling rubber ring (5) is embedded in the deep groove and covers the metal shielding ring (12), while the upper part extends to cover the annular shallow groove (111), forming a continuous sealing ring band; The wall of the annular shallow groove (111) is inclined at an angle of 60°-85° to the horizontal plane, forming an overflow guide surface.

8. The QFN chip package structure of claim 1, wherein: The sealing ring (3) is made of a transparent elastomer doped with phosphor, and its bottom extends out in a ring array of light guide teeth (13), which are inserted into the light guide hole (14) at the edge of the photosensitive chip (2). The top of the sealing ring (3) forms an annular reflective slope (15) of 45°±2°, which reflects the lateral incident light to the light incident area of ​​the filter glass (4).

9. The QFN chip package structure of claim 8, wherein: The light guide teeth (13) have a height of 0.2-0.5 mm and a diameter of 0.1-0.3 mm, and the center-to-center distance between adjacent light guide teeth (13) is 0.3-0.6 mm; the surface of the annular reflective slope (15) is covered with a metal reflective film.

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