CN103413814B - The preparation method of infrared focal plane device high density fine indium styletable face leveling - Google Patents

Abstract

The invention discloses a preparation method for leveling the end face of a high-density micro-indium column of an infrared focal plane device. The feature of leveling the end face of the indium column is that the lower knife is positioned, and the lower knife is finely adjusted by pushing up and down moving guide rails through an adjusting knob, and the knife edge falls to On the surface of the photoresist of the chip, lock the locking button, and translate the chip, and turn the platform adjustment knob to drive the platform moving guide rail to link the chip fixture platform and the chip to translate together. The biggest advantage of the present invention is: chip translation and knife edge scraping. The end surface of the indium column is smooth, bright and uniform. The diameter of the indium column is 10-12 microns, the center distance is 6-10 microns, and the height of the indium column can reach 8 microns.

Description

Preparation method of high-density micro-indium column end face leveling for infrared focal plane device

technical field

The invention relates to an infrared focal plane array detector, in particular to a preparation method for leveling the end face of a high-density fine indium column interconnected with a photosensitive element chip and a readout circuit in the infrared focal plane array detector.

Background technique:

One of the main performance parameters of an infrared focal plane array device is its imaging spatial resolution. The imaging spatial resolution characteristics of an infrared focal plane array device depend on the number and arrangement of photosensitive elements it contains. An M×N photosensitive element infrared focal plane array device includes M×N picture elements (M and N are positive integers).

The infrared focal plane array device mainly adopts a hybrid structure. The hybrid structure is to realize the mechanical and electrical connection of the manufactured M×N photosensitive element array chip and the silicon signal processing circuit with M×N input nodes through the indium column array. , so that signal sensitivity, signal readout and electronic scanning can be completed in one device. The advantage of the hybrid structure is that the process improvement and performance selection of the infrared detector array chip and the silicon signal processing circuit can be carried out separately, so as to ensure that the overall performance of the infrared focal plane array device is optimized. However, the realization of the hybrid structure is very difficult, and one of the keys is to grow high-density, thin-diameter, high enough and consistent indium column arrays on the infrared detector array chip and the silicon signal processing circuit chip, so that Make hybrid interconnects.

With the development of infrared focal plane component technology, the application of large-area array and small-aperture indium cylinder has attracted much attention, and it is required to prepare MCT (mercury cadmium telluride), InGaAs (indium gallium arsenide), GaN (gallium nitride) and other materials. The detector array chip, silicon CMOS readout circuit chip and white sapphire circuit substrate are prepared on-chip for two-dimensional staring type of 640×512 yuan, 1024×1024 yuan and above, and one-dimensional scanning type of 2048×1 yuan and above For the indium column array, the diameter of the indium column is required to be reduced to 8-10 microns, the center distance is 6-10 microns, and the height of the indium column is controlled at 8-12 microns. Due to the improvement of detector resolution, the process conditions of area array devices are becoming more and more stringent, and higher requirements are placed on the height uniformity and end surface flatness of each indium column.

The technical requirements for leveling the end faces of high-density micro-indium columns of infrared focal plane array devices include: a certain scale, such as 128×128 yuan, 256×256 yuan, etc.; high density, such as (2×10 ⁴ ~ 1×10 ⁵ ) pcs/cm ² ; fine diameter, for example (10-12) um; sufficient height and uniformity, such as (8-12) um, flat end surface, height uniformity of ±1um; high production rate, for example, the production rate is better than 99%.

For the preparation method of high-density micro-indium column end face leveling for infrared focal plane devices, it follows Zhu Jianmei's Chinese invention patent ZL200710045148.7 and implements a photoresist layer with a thickness of 14 microns on the chip - photoetching a 10× 10 micron square composite indium column holes - thermal evaporation deposition of about 600A gold layer - vacuum evaporation deposition of indium layer with 3 to 4 grams of indium - stripping off excess indium layer and excess gold indium alloy layer according to Chinese patent ZL02157697.1 - indium Column leveling - nitric acid etching to remove the edge of indium column - degumming and molding technical scheme, successfully prepared micro-fine indium column arrays for 128×128 element and 256×256 element infrared focal plane array devices. The prepared indium column has a diameter of 10-14 microns, a controllable height of 8-12 microns, and a height non-uniformity of ±1 micron.

Invention content:

The purpose of the present invention is to provide a preparation method for flattening the end faces of high-density micro-indium columns of infrared focal plane devices compatible with common silicon integrated circuit technology, so as to prepare indium column arrays that meet the requirements and meet the requirements of large-area array sizes. The needs of infrared focal plane device manufacturing.

The preparation method for leveling the end faces of high-density fine indium columns of the present invention relies on a device to realize: the device is shown in Figure 1, there is a bracket bone 1 and 2 at an angle of 90°, the bracket bone 1 is fixedly connected to the platform moving guide rail 3, and the bracket The bone 2 is fixedly connected to the up and down moving guide rail 4 , the chip fixture platform 5 is fixedly connected to the platform moving guide rail 3 , and the blade frame 6 is fixedly connected to the up and down moving guide rail 4 .

The feature of leveling the end face of the high-density micro-indium column of the present invention is that the combination of the positioning of the lower knife and the translation of the chip is completed. Since the positioning of the lower knife is the key to cutting into the end face of the micro-indium column, when the chip is translated, the end face of each indium column cut by the knife edge has a Leveling effect, resulting in the formation of high-density micro-indium cylinders with uniform height and flat end faces, as shown in Figure 2.

The preparation method of the high-density fine indium column end face leveling of the present invention is as follows: using the equipment conditions on the ordinary silicon integrated circuit process line, the chip surface is cleaned, coated with thick photoresist, exposed and developed, and vacuum evaporated. Gold accumulation layer and indium layer, use pressure-sensitive adhesive to peel off excess indium layer and excess gold-indium alloy layer, indium column leveling, nitric acid corrosion to remove the edge of indium column, deglue molding, and prepare a hybrid infrared focal plane The high-density fine indium column array of the device is shown in Figure 3.

Description of drawings:

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the planar effect drawing that the sample prepared by the present invention is taken with a Z-axis microscope;

Fig. 3 is a three-dimensional effect diagram taken by a scanning electron microscope of a sample prepared by the present invention.

Detailed ways:

Taking the 640×512 yuan chip as an example below, the specific implementation of the invention will be further described in detail in conjunction with the accompanying drawings:

1. According to the Chinese patent, patent number: ZL200710045148.7, title: "A Composite Indium Column for Infrared Focal Plane Devices and Its Preparation Method", implementation methods §1 to §5, prepare chips.

2. The indium column is leveled, see the structure shown in Figure 1 to fix the chip 7; put the chip into the chip fixture platform 5 smoothly, and then lower the knife for positioning. The said lower knife positioning is to move the guide rail up and down through the adjustment knob 8 4 Fine-tuning (controllable on the order of microns) the lower knife 9, gently drop the edge of the knife to the surface of the photoresist 10 of the chip, and then lock the locking button 11.

3. Turn the platform adjustment knob 12 to drive the platform moving guide rail 3 to link the chip fixture platform 5 and the chip 7 to translate together to obtain the end face 13 of the indium column.

4. Remove the above chip, immerse it in 10% HNO ₃ and let it stand for 1 minute to trim the edge of the indium column, then rinse it in flowing deionized water for 3 minutes, and dry it with nitrogen gas.

5. Remove the glue from the above chip, pour 2/3 cup of acetone solution, place the chip in it and shake slightly until the photoresist dissolves, then pour clean acetone and ethanol solution to wash it, and then expose the leveling After the indium cylinder. Fig. 3 is the photograph of embodiment.

Claims (1)

1. a preparation method for infrared focal plane device high density fine indium styletable face leveling, is characterized in that comprising the following steps:

First, pending chip (7) is placed on jig platform (5), lower cutter location, promote to move up and down the lower cutter (9) of guide rail (4) fine setting by the adjusting knob (8) that micron dimension is adjustable, the edge of a knife drops to the surface of chip photoresist (10), pin lock-button (11), turn platform adjusting knob (12) drives platform movement guide rail (3) chain to move chip fixture platform (5) and chip (7) translation together, obtains the indium styletable face (13) on chip;

Then take off chip, chip is immersed in the HNO that mass ratio is 10% ₃in, leave standstill and within 1 minute, repair except the fine and soft limit of indium post, then rinse 3 minutes in the deionized water of flowing, nitrogen dries up;

Finally to remove photoresist process to chip: pour 2/3 glass of acetone soln into, chip is placed in one weak vibrations, and photoresist dissolves and namely stops, then pours clean acetone into and alcohol mixed solution cleans, and exposes the indium cylinder after leveling.