Integrated circuit package, notably for image sensor, and method of positioning
The invention relates to the fabrication of integrated circuits in general, and notably the circuits of image sensors intended to form the electronic core of photographic apparatus or cameras. The chip is first aligned with respect to the package and then the package is aligned with respect to the optical system. The alignment of the chip with respect to the package is done optically. The alignment of the package with respect to the system is done mechanically with respect to the edges of the package. According to the invention, provision is made for optical marks to be provided on the package, these marks each having an edge aligned with a lateral edge of the package, so as to minimize the positioning errors which would be due to inaccurate positioning of the chip with respect to the edges of the package.
1. A multilayer ceramic integrated circuit package comprising:
an integrated circuit chip;
several optical indexing marks for positioning the integrated circuit chip in the package,
wherein each of the marks has an edge coincided with an exterior lateral edge of the package.
2. The integrated circuit package as claimed in claim 1 , wherein at least one of the marks is located on a first edge of the package and two of the marks are located on a second edge perpendicular to the first edge.
3. The integrated circuit package as claimed in claim 1 , wherein the marks have portions of a conducting layer that serves to form interconnection pads for soldering connection wires to the interconnection pads.
4. The package as claimed in claim 1 , wherein at least one mark is formed inside a notch formed on an upper surface of the package.
5. The package as claimed in claim 4 , wherein said as least one mark occupies the whole of the base of the notch.
6. The package as claimed in claim 1 , wherein the marks are formed on a peripheral ledge surrounding the whole of the periphery of the package and situated below the upper surface of the package.
7. The package as claimed in claim 1 , wherein the integrated circuit chip is soldered and linked electrically to the package, said chip being an image sensor for a camera.
8. The integrated circuit package as claimed in claim 7 , wherein a height of the marks above a flat base of the package is equal to the height of the upper surface of the chip above the flat base on which it is placed.
9. A method of accurate positioning of an image sensor chip with respect to an optical system of a camera, comprising
a step of optical alignment, by machine, of the chip in a multilayer ceramic integrated circuit package comprising at least one optical indexing mark, and
a step of mechanical positioning of the edges of the package with respect to the camera,
wherein the mark has an edge coincided with an exterior lateral edge of the package.
10. The method as claimed in claim 9 , wherein the multilayer ceramic package is fabricated by
superposing plates of green ceramic silk-screen-printed and cut according to desired patterns, and then
subdividing the superposition of plates of green ceramic into portions each corresponding to an individual package,
wherein the silk-screen-printed patterns comprise at least one indexing mark pattern extending at one and the same time over two adjacent portions, the division into individual portions being done along a line slicing this pattern into two marks each having an edge aligned with the cut edge of a respective package.
11. The integrated circuit package as claimed in claim 2 , wherein the marks have portions of a conducting layer that serves to form interconnection pads for soldering connection wires to the interconnection pads.
12. The package as claimed in claim 2 , wherein at least one mark is formed inside a notch formed on an upper surface of the package.
13. The package as claimed in claim 3 , wherein at least one mark is formed inside a notch formed on an upper surface of the package.
14. The package as claimed in claim 12 , wherein said at least one mark occupies the whole of the base of the notch.
15. The package as claimed in claim 13 , wherein said at least one mark occupies the whole of the base of the notch.
16. The package as claimed in claim 3 , wherein the integrated circuit chip is soldered and linked electrically to the package, said chip being an image sensor for a camera.
17. The integrated circuit package as claimed in claim 16 , wherein a height of the marks above a flat base of the package is equal to the height of the upper surface of the chip above the flat base on which it is placed.
18. The package as claimed in claim 4 , further comprising an integrated circuit chip soldered and linked electrically to the package, said chip being an image sensor for a camera.
19. The integrated circuit package as claimed in claim 18 , wherein a height of the marks above a flat base of the package is equal to the height of the upper surface of the chip above the flat base on which it is placed.