Infrared light source based on CMOS manufacturing process and manufacturing method thereof

Abstract

The invention relates to an infrared light source based on a CMOS manufacturing process and a manufacturing method of the infrared light source. The infrared light source comprises a semiconductor substrate, a supporting layer, a first metal layer, a dielectric layer and a second metal layer which are sequentially arranged from bottom to top. The dielectric layer has the functions of front protection and infrared radiation, and replaces a traditional blackbody radiation layer; a cavity is formed in the back surface of the semiconductor substrate, so that heat loss is reduced, and the electric modulation response speed is increased; the manufacturing method comprises the steps of substrate preparation, supporting layer deposition, first metal layer patterning, dielectric layer patterning, second metal layer patterning and back surface cavity etching. The structure does not comprise a traditional black-body radiation layer, but adopts the dielectric layer in the CMOS technology to replace the dielectric layer, the CMOS technology is completely compatible, the problems that an MEMS light source is low in productivity, low in yield and high in cost are solved, meanwhile, single-chip integrated manufacturing with a light source driving circuit is supported, and the wide prospect is achieved in the aspects of miniaturization and integration.

Description

Technical Field

[0001] The present invention relates to the field of infrared technology, and in particular to an infrared light source based on a CMOS manufacturing process and a manufacturing method thereof. Background Art

[0002] Non-dispersive infrared (NDIR) gas sensors, based on spectral absorption principles, primarily consist of an infrared light source, a gas chamber, a filter, and an infrared detector. The infrared light source is a key component in determining the performance of NDIR integrated gas sensors, directly determining their size, power consumption, and detection performance. Traditional infrared light sources (such as tungsten filament lamps or laser diodes) suffer from large size, high power consumption, and complex manufacturing processes. MEMS radiation light sources, due to their superior electrical modulation performance, are currently gaining popularity in the market.

[0003] However, MEMS radiation sources are typically manufactured using MEMS technology, which, due to its specialized blackbody radiation layer structure, is incompatible with CMOS technology. Compared to standard CMOS technology, MEMS technology has the disadvantages of low throughput, low yield, and high cost, making it unsuitable for large-scale mass production. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide an infrared light source based on CMOS manufacturing process and a manufacturing method thereof, so as to solve the problems such as mass production bottleneck caused by the incompatibility between MEMS light source and CMOS process.

[0005] To achieve the above object, the technical solution adopted by the present invention is: an infrared light source based on a CMOS manufacturing process, comprising a semiconductor substrate, a support layer, a first metal layer, a dielectric layer and a second metal layer; The support layer is provided on the semiconductor substrate to provide mechanical stability of the structure; The first metal layer is provided on the support layer and is used for heating the chip; The dielectric layer is provided on the first metal layer for front protection and also serves as an infrared radiation layer; The second metal layer is provided on the dielectric layer and is used for interconnecting the leads of the structure and serves as a pad; The back side of the semiconductor substrate is provided with a cavity, which reduces the heat loss of the infrared light source on the one hand, and improves the electrical modulation response speed of the structure on the other hand.

[0006] The present invention also discloses a method for manufacturing an infrared light source based on a CMOS manufacturing process, comprising the following steps: S01 provides a growth semiconductor substrate; S02 depositing a support layer above the semiconductor substrate; S03 depositing a first metal layer above the support layer and performing photolithographic patterning; S04 depositing a dielectric layer above the first metal layer and performing photolithographic patterning; S05 depositing a second metal layer above the dielectric layer and performing photolithographic patterning; S06. Etching the back side of the substrate to form a cavity.

[0007] Preferably, the semiconductor substrate in S01 is silicon or other substrates; Preferably, the support layer deposited in S02 is one of silicon oxide, silicon nitride or a composite film, and its thickness is 0.3um-10um; Preferably, the first metal layer deposited in S03 is one of tungsten (W), aluminum (Al), and polysilicon (Poly-Si), and has a thickness of 0.1 um-1 um.

[0008] Preferably, the dielectric layer deposited in S04 is one of silicon oxide, silicon nitride or a composite film, and has a thickness of 0.3um-10um.

[0009] Preferably, the radiation wavelength of the dielectric layer covers the 3-14 μm band, and the operating temperature is ≥500° C.

[0010] Preferably, in S04, the dielectric layer is patterned into a radiation area by a photolithography process to expose the second metal layer pad.

[0011] Preferably, the second metal layer deposited in S05 is aluminum, and its thickness is 0.1um-1um.

[0012] Preferably, the cavity in S06 is formed by wet etching or dry etching.

[0013] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: Since the structure of the present invention does not include a traditional blackbody radiation layer, but instead uses a dielectric layer in the CMOS process, it is fully compatible with the CMOS process. At the same time, the dielectric layer in the structure can also act as an infrared radiation layer to a certain extent, and the wavelength range covered can basically meet conventional application requirements. Compared with the MEMS process, this infrared light source based on the CMOS manufacturing process has the advantages of high production capacity, high yield and low cost, and supports single-chip integrated manufacturing with the light source driving circuit, and has greater prospects in miniaturization and integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The technical solution of the present invention will be further described below with reference to the accompanying drawings: Attachment Figure 1This is a flowchart of the manufacturing process of the infrared light source based on the CMOS manufacturing process of the present invention; Attachment Figure 2 It is a cross-sectional schematic diagram of the initial growth substrate in the present invention; Attachment Figure 3 is a schematic cross-sectional view after the support layer is deposited in the present invention; Attachment Figure 4 is a schematic cross-sectional view after the first metal layer is deposited in the present invention; Attachment Figure 5 It is a cross-sectional schematic diagram after the dielectric layer is deposited in the present invention; Attachment Figure 6 is a schematic cross-sectional view after the second metal layer is deposited in the present invention; Attachment Figure 7 This is a cross-sectional schematic diagram of the infrared light source formed after a cavity is etched on the back side of the substrate in the present invention.

[0015] Wherein: 1. semiconductor substrate; 2. support layer; 3. first metal layer; 4. dielectric layer; 5. second metal layer; 6. cavity. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] Attachment Figure 7 The infrared light source based on the CMOS manufacturing process of the present invention comprises a semiconductor substrate 1, a support layer 2, a first metal layer 3, a dielectric layer 4 and a second metal layer 5; The support layer 2 is deposited on the entire surface and is located above the semiconductor substrate 1 to provide mechanical stability to the light source structure; The first metal layer 3 is deposited on the support layer 2 and patterned by a photolithography process. The first metal layer 3 is a heating resistor. When the light source is working, it is energized, and the Joule heat generated causes the temperature of the light source working area to rise, thereby generating infrared radiation to the outside world. The dielectric layer 4 is deposited above the first metal layer 3 and is patterned by a photolithography process. The dielectric layer 4 is used for front protection because the maximum surface temperature exceeds 500°C when the light source is working. The dielectric layer 4 can ensure that the first metal layer 3 and the light source structure are not corroded when working at high temperatures, providing good long-term reliability for the light source. It also acts as an infrared radiation layer. Its infrared emissivity is lower than that of an ideal blackbody radiation layer, but the radiation wavelength range can basically meet conventional application requirements.

[0018] The second metal layer 5 is used for interconnecting the leads of the structure and serves as a pad; A cavity 6 is etched on the back side of the semiconductor substrate 1 to reduce heat loss during operation of the light source and also to improve the electrical modulation response speed of the structure.

[0019] like Figure 1-7 As shown, the manufacturing method of the infrared light source based on the CMOS manufacturing process of the present invention comprises the following steps: S01 provides a growth semiconductor substrate 1; S02 depositing a support layer 2 above the semiconductor substrate 1; S03 depositing a first metal layer 3 above the support layer 2 and performing photolithographic patterning; S04 deposits a dielectric layer 4 above the first metal layer 3 and performs photolithographic patterning; S05 depositing a second metal layer 5 above the dielectric layer 4 and performing photolithographic patterning; S06. Etching the back side of the substrate to form a cavity 6.

[0020] In the embodiment of the present invention, the semiconductor substrate 1 in step S01 is silicon.

[0021] In the embodiment of the present invention, the support layer 2 deposited in step S02 is one of silicon oxide, silicon nitride or a composite film, and its thickness is 0.3um-10um. Figure 3 As shown, the support layer 2 is deposited on the entire surface without being patterned, which effectively ensures the mechanical stability of the light source structure.

[0022] In the embodiment of the present invention, the first metal layer 3 deposited in step S03 is made of a material such as tungsten (W), aluminum (Al), polysilicon (Poly-Si) that complies with standard CMOS processing technology, and has a thickness of 0.1 um-1 um.

[0023] In the embodiment of the present invention, the dielectric layer 4 deposited in step S04 is one of silicon oxide, silicon nitride or a composite film, and has a thickness of 0.3 um to 10 um.

[0024] In the embodiment of the present invention, the second metal layer 5 deposited in step S05 is aluminum (Al), and its thickness is 0.1 um-1 um.

[0025] In the embodiment of the present invention, the silicon etching method adopted in step S06 is wet etching or dry etching.

[0026] The above are only specific application examples of the present invention and do not constitute any limitation on the scope of protection of the present invention. Any technical solutions formed by equivalent transformation or equivalent replacement shall fall within the scope of protection of the present invention.

Claims

1. An infrared light source based on CMOS manufacturing technology, characterized by: It comprises a semiconductor substrate, a support layer, a first metal layer, a dielectric layer and a second metal layer; The support layer is provided on the semiconductor substrate to provide mechanical stability; The first metal layer is provided on the support layer and is used for electrical heating; The dielectric layer is provided on the first metal layer for high temperature protection and as an infrared radiation layer; The second metal layer is provided on the dielectric layer and is used for lead interconnection; A cavity is provided on the back side of the semiconductor substrate to reduce heat loss and improve response speed.

2. A method for manufacturing an infrared light source based on a CMOS manufacturing process, characterized in that: The following steps are involved: S01. Providing a semiconductor substrate; S02, depositing a support layer on the semiconductor substrate; S03, depositing and patterning a first metal layer on the supporting layer; S04, depositing and patterning a dielectric layer on the first metal layer; S05, depositing and patterning a second metal layer on the dielectric layer; S06. Etching the back side of the substrate to form a cavity.

3. The method for manufacturing an infrared light source based on a CMOS manufacturing process according to claim 2, wherein: The semiconductor substrate in S01 is silicon.

4. The method for manufacturing an infrared light source based on a CMOS manufacturing process according to claim 2, wherein: The support layer deposited in S02 is one of silicon oxide, silicon nitride or a composite film, and its thickness is 0.3um-10um.

5. The method for manufacturing an infrared light source based on a CMOS manufacturing process according to claim 2, wherein: The first metal layer deposited in S03 is one of tungsten, aluminum, and polysilicon, and has a thickness of 0.1um-1um.

6. The method for manufacturing an infrared light source based on a CMOS manufacturing process according to claim 2, wherein: The dielectric layer deposited in S04 is one of silicon oxide, silicon nitride or a composite film, and its thickness is 0.3um-10um.

7. The method for manufacturing an infrared light source based on a CMOS manufacturing process according to claim 2, wherein: The radiation wavelength of the dielectric layer covers the 3-14 μm band, and the operating temperature is ≥500° C.

8. The method for manufacturing an infrared light source based on a CMOS manufacturing process according to claim 2, wherein: In S04, the dielectric layer is patterned into a radiation area through a photolithography process, exposing the second metal layer pad.

9. The method for manufacturing an infrared light source based on a CMOS manufacturing process according to claim 2, wherein: The second metal layer deposited in S05 is aluminum, and its thickness is 0.1um-1um.

10. The method for manufacturing an infrared light source based on a CMOS manufacturing process according to claim 2, wherein: The cavity in S06 is formed by wet or dry etching.

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