CN-122028556-A - Flip LED chip and preparation method thereof

Abstract

The invention discloses a flip LED chip and a preparation method thereof, and relates to the technical field of semiconductors, wherein the method comprises the steps of providing an LED epitaxial wafer, comprising a substrate, an N-type semiconductor layer, a light-emitting layer and a P-type semiconductor layer; the method comprises the steps of depositing a transparent conducting layer on a P-type semiconductor layer, forming a patterned mask layer on the transparent conducting layer, carrying out dry etching on the transparent conducting layer, the P-type semiconductor layer below and a luminescent layer by taking the patterned mask layer as an etching mask to simultaneously form an MSA step with a first depth and an ISO step with a second depth, wherein the patterned mask layer is prepared by a single photoetching process and comprises the steps of sequentially carrying out first exposure, second exposure and first development after photoresist is coated on the surface of a structure to be etched, wherein the first exposure is used for defining the pattern of the MSA step, and the second exposure is used for defining the pattern of the ISO step. The invention etches steps with different depths at one time by a single photoetching double exposure process, thereby remarkably reducing the manufacturing cost and the period.

Inventors

• WU ZIHAN
• XU ZHOU
• ZOU YANLING
• ZHANG CUNLEI
• HU JIAHUI
• Jin Conglong

Assignees

• 江西耀驰科技有限公司
• 江西兆驰半导体有限公司

Dates

Publication Date

20260512

Application Date

20251231

Claims (10)

1. 1. The preparation method of the flip LED chip is characterized by comprising the following steps of: providing an LED epitaxial wafer, wherein the LED epitaxial wafer comprises a substrate, and an N-type semiconductor layer, a light-emitting layer and a P-type semiconductor layer which are sequentially laminated on the substrate; Depositing a transparent conductive layer on the P-type semiconductor layer; Forming a patterned mask layer on the transparent conductive layer; Taking the patterned mask layer as an etching mask, and carrying out dry etching on the transparent conductive layer, the P-type semiconductor layer below the transparent conductive layer and the luminous layer so as to form an MSA step with a first depth and an ISO step with a second depth in the LED epitaxial wafer at the same time, wherein the first depth is smaller than the second depth; The patterned mask layer is prepared through a single photoetching process, and the single photoetching process comprises the following steps: and after coating photoresist on the surface of the structure to be etched, sequentially performing first exposure, second exposure and primary development, wherein the first exposure is used for defining the pattern of the MSA step, and the second exposure is used for defining the pattern of the ISO step.
2. 2. The method of manufacturing a flip-chip LED chip of claim 1, wherein said first exposure and said second exposure are at least partially non-overlapping.
3. 3. The method of manufacturing a flip-chip LED chip of claim 2, wherein said second exposure area completely surrounds said first exposure area.
4. 4. The method of manufacturing a flip-chip LED chip according to claim 3, The first exposure and the second exposure adopt the same mask plate, and the exposure of different areas is realized by moving a sample table or changing an optical path, or the first exposure and the second exposure adopt different mask plates.
5. 5. The method of manufacturing a flip-chip LED chip of claim 4, wherein said first exposure uses an exposure energy less than an exposure energy of said second exposure.
6. 6. The method of manufacturing a flip-chip LED chip of claim 1, wherein said patterned mask layer formed after development has a first thickness in a region corresponding to said MSA and a second thickness in a region corresponding to said ISO step by controlling parameters of said first exposure and said second exposure, wherein said first thickness is greater than said second thickness.
7. 7. The method of manufacturing a flip-chip LED chip of claim 6, wherein said dry etching is anisotropic etching, and wherein said patterned mask layer is etched simultaneously during etching.
8. 8. The method of manufacturing a flip-chip LED chip of any of claims 1-7, further comprising, after said dry etching step: removing the patterned mask layer; forming a P-type electrode on the MSA step; Forming an N-type electrode on the exposed N-type semiconductor layer; And forming a metal bonding pad layer on the P-type electrode and/or the N-type electrode to finish the preparation of the flip LED chip.
9. 9. A flip-chip LED chip, characterized in that it is produced by the production method according to any one of claims 1 to 8.
10. 10. The flip-chip LED chip of claim 9, wherein the sidewall profile between the MSA mesa and the ISO mesa is a continuous topography formed by one etch.

Description

Flip LED chip and preparation method thereof Technical Field The invention relates to the technical field of semiconductors, in particular to a flip LED chip and a preparation method thereof. Background The flip LED chip constructs a complex multilayer structure comprising a high-efficiency luminous epitaxial layer, a current blocking layer, a transparent conducting layer, an electrode-1, a reflecting layer, an electrode-2 and the like through precise thin film deposition, photoetching, etching (dry method/wet method) and other semiconductor processes. The flip LED chip has the advantages of excellent heat radiation performance, high luminous efficiency, higher safety and reliability, small size, easy integration, good optical matching performance and the like, and has wide application prospect and market potential in the LED industry. The photoetching process is not only a core link of pattern transfer in the manufacture of LED chips (especially Micro-LEDs), but also a key technology for determining the performance, yield and mass production feasibility of the chips. However, as process nodes shrink to the micron and even sub-micron level, the cost and time pressures associated with multiple lithography steps are increasingly significant. However, the flip-chip LED chip requires to build a multi-layer fine structure, and the photolithography process steps are significantly increased, generally 1.5-2 times that of the normal chip, resulting in prolonged manufacturing cycle of a single chip, and simultaneously, exponentially rising mask loss, equipment time and material cost, and finally resulting in increased comprehensive cost. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide an LED packaging method based on a fluorescent membrane and an LED device, and aims to solve the problems described in the prior art. The first aspect of the present invention provides a method for preparing a flip-chip LED chip, the method comprising: providing an LED epitaxial wafer, wherein the LED epitaxial wafer comprises a substrate, and an N-type semiconductor layer, a light-emitting layer and a P-type semiconductor layer which are sequentially laminated on the substrate; Depositing a transparent conductive layer on the P-type semiconductor layer; Forming a patterned mask layer on the transparent conductive layer; Taking the patterned mask layer as an etching mask, and carrying out dry etching on the transparent conductive layer, the P-type semiconductor layer below the transparent conductive layer and the luminous layer so as to form an MSA step with a first depth and an ISO step with a second depth in the LED epitaxial wafer at the same time, wherein the first depth is smaller than the second depth; The patterned mask layer is prepared through a single photoetching process, and the single photoetching process comprises the following steps: and after coating photoresist on the surface of the structure to be etched, sequentially performing first exposure, second exposure and primary development, wherein the first exposure is used for defining the pattern of the MSA step, and the second exposure is used for defining the pattern of the ISO step. According to an aspect of the foregoing technical solution, the exposure areas of the first exposure and the second exposure are at least partially non-overlapping. According to an aspect of the above technical solution, the exposure area of the second exposure completely encloses the exposure area of the first exposure. According to one aspect of the above technical solution, the first exposure and the second exposure are both performed by using the same mask, and exposure of different areas is performed by moving the sample stage or changing the optical path, or the first exposure and the second exposure are performed by using different masks. According to an aspect of the foregoing technical solution, the exposure energy used for the first exposure is smaller than the exposure energy used for the second exposure. According to one aspect of the above technical solution, by controlling parameters of the first exposure and the second exposure, the patterned mask layer formed after development has a first thickness in a region corresponding to the MSA and a second thickness in a region corresponding to the ISO step, wherein the first thickness is greater than the second thickness. According to an aspect of the above technical solution, the dry etching is anisotropic etching, and in the etching process, the patterned mask layer is etched synchronously. According to an aspect of the foregoing technical solution, after the dry etching step, the method further includes: removing the patterned mask layer; forming a P-type electrode on the MSA step; Forming an N-type electrode on the exposed N-type semiconductor layer; And forming a metal bonding pad layer on the P-type electrode and/or the N-type electrode to finish the preparation of the flip LED ch