An infrared detector dicing method

Abstract

This invention proposes a method for dicing infrared detectors, comprising: placing a wafer of an infrared detector chip, prepared and coated with a protective layer, onto the working platform of a laser cold dicing machine for vacuum adsorption; using the laser cold dicing machine to sequentially remove the protective layer, groove, and cut along the dicing lines of the infrared detector chip; removing and cleaning the diced infrared detector chip; the method provided by this invention can avoid the hard damage caused by grinding wheel dicing, and will not produce any chipping or cracking, thereby improving the yield and reliability of infrared detector hybrid chips.

Description

Technical Field

[0001] This application relates to the field of infrared focal plane detector technology, and in particular to a method for dicing infrared detectors. Background Technology

[0002] Hybrid infrared focal plane detectors are created by coupling an infrared detector chip and a dedicated readout circuit using flip-chip interconnects via indium pillars. In large-area arrays and long linear arrays, the device size is now very large. The long-term stability and reliability of these interconnected devices under extreme temperature shocks is a critical issue. Hybrid chips typically operate at liquid nitrogen temperature (77K). However, during the transition from room temperature to liquid nitrogen, the significant difference in thermal expansion coefficients between the detector material and the readout circuit silicon (Si) causes the infrared detector chip to experience substantial shear stress. After repeated high-low temperature cycles, edge chipping or micro-cracks can lead to chip breakage.

[0003] Therefore, it is necessary to solve the process problems of edge chipping and cracking around the infrared detector to improve device performance and reliability. Summary of the Invention

[0004] The technical solution adopted in this invention is to solve the manufacturing problem of edge chipping and cracking around the perimeter of an infrared detector, thereby improving device performance and reliability. In view of this, this invention provides a method for scribing an infrared detector.

[0005] The present invention provides a method for dicing an infrared detector, comprising: Step 1: Place the prepared infrared detector chip wafer with a protective coating on its surface into the working platform of the laser cold cutting dicing machine for vacuum adsorption. Step 2: Using the laser cold cutting scribing machine, the protective layer is removed, grooved, and cut sequentially along the scribing line of the infrared detector chip; Step 3: Remove the diced infrared detector chip and clean it.

[0006] In one embodiment, the process of removing the protective layer specifically includes: An ultrashort femtosecond pulse solid-state laser with a wavelength of 520nm and a pulse width of ≤400fs was used. A precision temperature-controlled water-cooling system was employed, and the laser parameters were 11 pulses with a frequency of 500KHz and an energy of 30% in a processing speed of 1000mm / s to remove the protective layer.

[0007] In one embodiment, the grooving process specifically includes: An ultrashort femtosecond pulse solid-state laser with a wavelength of 520nm and a pulse width of ≤400fs was used. A precision temperature-controlled water-cooling system was employed, and the laser parameters were 500KHz frequency, 2% energy, 1 pulse mode, and a processing speed of 100mm / s for the grooving process.

[0008] In one embodiment, the cutting process specifically includes: An ultrashort femtosecond pulse solid-state laser with a wavelength of 520nm and a pulse width of ≤400fs is used. A precision temperature-controlled water-cooling system is employed, and the laser parameters are 500KHz frequency, 30% energy, 1-pulse mode, and a processing speed of 4000mm / s for the cutting process.

[0009] In one embodiment, the cleaning process specifically includes: Use an anhydrous ethanol spray gun to clean the current dicing process, removing any residue and protective adhesive that may have splashed onto the device surface during dicing.

[0010] In one embodiment, the dicing depth of the laser cold cutting dicing machine during protective layer removal is equal to the thickness of the protective layer.

[0011] In one embodiment, the grooving depth of the laser cold cutting scribing machine is 20 micrometers.

[0012] In one embodiment, the laser cold cutting dicing machine directly cuts through the current chip during the cutting process.

[0013] In one embodiment, the depth of the protective layer is 5 micrometers.

[0014] By adopting the above technical solution, the present invention has at least the following advantages: The method provided by this invention can avoid hard damage from grinding wheel dicing, and will not produce any chipping or cracks, thereby improving the yield and reliability of infrared detector hybrid chips. Attached Figure Description

[0015] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic flowchart of an infrared detector dicing method according to an embodiment of the present invention; Figure 2 The dicing path after the wafer grooving process of the infrared detector chip according to an embodiment of the present invention; Figure 3 as well as Figure 4The image shows the dicing marks after the wafer dicing process of the infrared detector chip according to an embodiment of the present invention. Detailed Implementation

[0016] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

[0017] While exemplary embodiments of the invention are shown in the accompanying drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey its scope to those skilled in the art. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] According to an embodiment of the present invention, an infrared detector dicing method and apparatus are provided, such as... Figure 1 As shown, it includes the following steps: Step 1: Place the prepared infrared detector chip wafer with a protective coating onto the working platform of the laser cold cutting dicing machine for vacuum adsorption; Step 2: Use a laser cold cutting scribing machine to remove the protective layer along the scribing line of the infrared detector chip. Use an ultrashort femtosecond pulse solid-state laser (wavelength: 520nm, pulse width: ≤400fs) with a precision temperature-controlled water cooling system. The laser parameters are 500KHz frequency, 30% energy in 11-pulse mode, and processing speed of 1000mm / s to remove the protective layer. Step 3: Use a laser cold cutting scribing machine to perform grooving along the scribing line of the infrared detector chip. Use an ultrashort femtosecond pulse solid-state laser (wavelength: 520nm, pulse width: ≤400fs) with a precision temperature control water cooling system. The laser parameters are 500KHz frequency, 2% energy in 1-pulse mode, and processing speed of 100mm / s to perform the grooving process. Step 4: Use a laser cold cutting dicing machine to cut along the dicing line of the infrared detector chip. Use an ultrashort femtosecond pulse solid-state laser (wavelength: 520nm, pulse width: ≤400fs) with a precision temperature control water cooling system. The laser parameters are 500KHz frequency, 30% energy in 1-pulse mode, and processing speed of 4000mm / s. Step 5: Remove the diced infrared detector chip and clean it with an anhydrous ethanol spray gun to remove any residue and protective adhesive splashed onto the device surface during dicing. This laser dicing (protective layer removal + grooving + cutting process) can avoid edge chipping and cracks around the infrared detector, improving device performance and reliability.

[0019] In step 1, the wafer of the infrared detector chip is placed on the working platform of the laser cold cutting dicing machine for vacuum adsorption, ensuring that the wafer chip will not move at all.

[0020] In step 2, a laser cold cutting dicing machine is used to remove the protective layer along the dicing line of the infrared detector chip to a depth equal to the thickness of the protective layer, approximately 5 micrometers.

[0021] In step 3, a laser cold cutting dicing machine is used to perform a grooving process along the dicing line of the infrared detector chip, with a depth of about 20 micrometers.

[0022] In step 4, a laser cold cutting dicing machine is used to cut along the dicing line of the infrared detector chip, cutting directly through it.

[0023] The following will combine Figures 1 to 4 The method provided in this embodiment will be described in detail, including the following steps: Step 100: Place the prepared infrared detector chip wafer with a protective coating on its surface into the working platform of the laser cold cutting dicing machine for vacuum adsorption to ensure that the wafer chip does not move at all; Step 200: Use a laser cold cutting dicing machine to remove the protective layer along the dicing lines of the infrared detector chip. The depth is equal to the thickness of the protective layer, approximately 5 micrometers. Use an ultrashort femtosecond pulse solid-state laser (wavelength: 520nm, pulse width: ≤400fs) with a precision temperature-controlled water cooling system. Draw lines from the inside out, with an interval of 0.002mm, for 20 lines. The laser parameters are 500kHz, 30% energy, 1 pulse, and a cutting speed of 1000mm / s. Step 300: Use a laser cold cutting scribing machine to perform a grooving process along the scribing lines of the infrared detector chip, with a depth of about 20 micrometers; use an ultrashort femtosecond pulse solid-state laser (wavelength: 520nm, pulse width: ≤400fs), plus a precision temperature-controlled water cooling system, scribing from the inside out, with an interval of 0.002mm, 18 lines, laser parameters of 500kHz, energy 2%, 1 pulse, and cutting speed of 100mm / s; Step 400: Use a laser cold cutting scribing machine to cut along the scribing line of the infrared detector chip to a depth of about 900 micrometers; use an ultrashort femtosecond pulse solid-state laser (wavelength: 520nm, pulse width: ≤400fs), plus a precision temperature-controlled water cooling system, to perform single-line scribing, 0mm interval, 1 line, laser parameters 500kHz, energy 30%, 1 pulse, cutting speed 4000mm / s; Step 500: Remove the diced infrared detector chip and clean it with an anhydrous ethanol spray gun to remove any residue and protective adhesive splashed onto the device surface during dicing. This laser dicing process avoids the hard damage caused by grinding wheels, prevents edge chipping and cracking, and improves the yield and reliability of the infrared detector hybrid chip.

[0024] In summary, the present invention can solve the process problems of edge chipping and cracking caused by dicing of infrared detector grinding wheels, and improve the yield and reliability of infrared detector hybrid chips.

[0025] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims. All of these forms are within the protection scope of this application.

Claims

1. A method of dicing an infrared detector, comprising: include: Step 1: Place the prepared infrared detector chip wafer with a protective coating on its surface into the working platform of the laser cold cutting dicing machine for vacuum adsorption. Step 2: Using the laser cold cutting scribing machine, the protective layer is removed, grooved, and cut sequentially along the scribing line of the infrared detector chip; Step 3: Remove the diced infrared detector chip and clean it.

2. The infrared detector dicing method of claim 1, wherein, In step 2, the process of removing the protective layer specifically includes: An ultrashort femtosecond pulse solid-state laser with a wavelength of 520nm and a pulse width of ≤400fs was used. A precision temperature-controlled water-cooling system was employed, and the laser parameters were 11 pulses with a frequency of 500KHz and an energy of 30% in a processing speed of 1000mm / s to remove the protective layer.

3. The infrared detector dicing method of claim 2, wherein, In step 2, the grooving process specifically includes: An ultrashort femtosecond pulse solid-state laser with a wavelength of 520nm and a pulse width of ≤400fs was used. A precision temperature-controlled water-cooling system was employed, and the laser parameters were 500KHz frequency, 2% energy, 1 pulse mode, and a processing speed of 100mm / s for the grooving process.

4. The infrared detector dicing method of claim 3, wherein, In step 2, the cutting process specifically includes: An ultrashort femtosecond pulse solid-state laser with a wavelength of 520nm and a pulse width of ≤400fs is used. A precision temperature-controlled water-cooling system is employed, and the laser parameters are 500KHz frequency, 30% energy, 1-pulse mode, and a processing speed of 4000mm / s for the cutting process.

5. The infrared detector dicing method of claim 4, wherein, In step 3, the cleaning process specifically includes: Use an anhydrous ethanol spray gun to clean the current dicing process, removing any residue and protective adhesive that may have splashed onto the device surface during dicing.

6. The infrared detector dicing method of claim 1, wherein, In step 2, the dicing depth of the laser cold cutting dicing machine when removing the protective layer is the thickness of the protective layer.

7. The infrared detector dicing method of claim 1, wherein, In step 2, the grooving depth of the laser cold cutting scribing machine is 20 micrometers.

8. The infrared detector dicing method of claim 1, wherein, In step 2, the laser cold cutting dicing machine directly cuts through the current chip during the cutting process.

9. The infrared detector dicing method of claim 6, wherein, The depth of the protective layer is 5 micrometers.

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