End surface processing method of optoelectronic chip

Abstract

The present invention relates to a method for processing the end face of an optoelectronic chip, the method comprising: making a plurality of grooves on a surface having a bump on the optoelectronic chip, the grooves being axially symmetrically distributed along any one central axis of the optoelectronic chip, and making one groove every 300 μm-1000 μm on the central axis of the optoelectronic chip, making at least four grooves in a preset clamping area, and making at least four grooves in a non-clamping area; then covering the surface having a bump on the optoelectronic chip with a protective sheet having a raised structure, fixing it by fitting the raised structure and the grooves, and filling it with an adhesive to form a composite structure, then clamping the end face of the optoelectronic chip with a fixture and performing a grinding and polishing process, removing the protective sheet and the adhesive, and obtaining the processed optoelectronic chip. The method of the present invention can protect the bumps of the optoelectronic chip and, by controlling the distribution of the grooves, can reduce the stress at a single point position and prevent damage to the optoelectronic chip.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic integration, and in particular to an end face processing method of an optoelectronic chip. Background Art

[0002] Optoelectronic chips are integrated chips that fuse photonic and electronic technologies, combining ultra-high speed, low power consumption, high bandwidth, and resistance to electromagnetic interference. Through photonic integration, they achieve ultra-high-speed data transmission and signal processing, consuming significantly less energy than purely electronic solutions. They are primarily used in data center optical interconnects, 5G / 6G communication base stations, fiber-optic sensor networks, medical imaging equipment, and autonomous driving lidar, driving breakthroughs in energy efficiency and performance for next-generation computing, communication, and perception systems.

[0003] The surface of an optoelectronic chip usually contains a series of bumps for subsequent electrical packaging. However, the production of the bumps will seriously degrade the performance of the port, making it necessary to grind and polish the end face of the optoelectronic chip. However, when grinding and polishing the end face of the optoelectronic chip, the surface of the optoelectronic chip needs to be clamped. When the clamp is in direct contact with the surface of the optoelectronic chip, the bumps on it are often damaged, seriously affecting the subsequent packaging process. To solve this problem, the traditional method is usually to directly cover the surface of the optoelectronic chip with a protective sheet. However, this method is prone to relative displacement between the protective sheet and the chip during processing, and the reliability is not high. Summary of the Invention

[0004] Based on this, it is necessary to provide a method for processing the end face of an optoelectronic chip to address the above problem, wherein the method can simultaneously protect the bumps and the optoelectronic chip itself from damage.

[0005] A method for processing an end face of an optoelectronic chip comprises the following steps:

[0006] Making a plurality of grooves on the surface of the optoelectronic chip having the bumps, wherein the grooves are axially symmetrically distributed along any central axis of the optoelectronic chip, and one groove is made every 300 μm to 1000 μm on the central axis of the optoelectronic chip, at least four grooves are made in a preset clamping area, and at least four grooves are made in a non-clamping area;

[0007] Covering the surface of the optoelectronic chip having the bumps with a protective sheet, wherein the surface of the protective sheet has a raised structure that can be matched with the groove in the optoelectronic chip, and the height of the raised structure is greater than the sum of the depth of the groove and the height of the bump, the raised structure is embedded in the groove to fix the optoelectronic chip and the protective sheet, and an adhesive is filled between the optoelectronic chip and the protective sheet to form a composite structure;

[0008] The composite structure is clamped by a fixture, wherein the clamping position of the fixture corresponds to a preset clamping area of ​​the optoelectronic chip, and then the end surface of the optoelectronic chip is ground and polished;

[0009] After the grinding and polishing process is completed, the protective sheet and the adhesive are removed to obtain a processed optoelectronic chip.

[0010] In one embodiment, a groove is formed every 600 μm to 800 μm on the central axis of the optoelectronic chip;

[0011] and / or, making 4-6 grooves in the predetermined clamping area;

[0012] And / or, 8-10 grooves are made in the non-clamping area.

[0013] In one embodiment, a vertical distance between the groove in the predetermined clamping area and the edge of the optoelectronic chip is greater than or equal to 400 μm;

[0014] and / or, a vertical distance between the groove in the non-clamping area and the edge of the optoelectronic chip is greater than or equal to 400 μm;

[0015] And / or, a vertical distance between the groove in the preset clamping area and the central axis is greater than or equal to 300 μm;

[0016] And / or, a vertical distance between the groove in the non-clamping area and the central axis is greater than or equal to 300 μm.

[0017] In one embodiment, within the predetermined clamping area, the distance between the grooves is greater than or equal to 400 μm;

[0018] and / or, in the non-clamping area, the distance between the grooves is greater than or equal to 400 μm;

[0019] And / or, the distance between the groove in the preset clamping area and the groove in the non-clamping area is greater than or equal to 400 μm.

[0020] In one embodiment, the optoelectronic chip has two non-clamping areas, and the groove is formed in each non-clamping area.

[0021] In one embodiment, the depth of the groove is 80 μm-300 μm;

[0022] And / or, the maximum physical dimension of the groove is greater than or equal to 100 μm.

[0023] In one embodiment, the sum of the depth of the groove and the height of the protrusion differs from the height of the protrusion structure by 50 μm-100 μm.

[0024] In one embodiment, the adhesive completely fills the gap between the optoelectronic chip and the protective sheet.

[0025] In one embodiment, the Young's modulus of the protective sheet is greater than or equal to 70 GPa;

[0026] And / or, the thickness of the protective sheet is greater than or equal to 1 mm;

[0027] And / or, the adhesive does not react with acidic substances and alkaline substances.

[0028] In one embodiment, the protective sheet is selected from a silicon oxide sheet, a silicon sheet, a silicon nitride sheet or a glass sheet;

[0029] And / or, the adhesive is selected from one or more of paraffin wax, epoxy resin, UV adhesive or photoresist.

[0030] In the present invention, the composite structure of the protective sheet, adhesive, and optoelectronic chip prevents direct contact between the bumps of the optoelectronic chip and the fixture or protective sheet during polishing, fully protecting the bumps of the optoelectronic chip from damage. Furthermore, by creating grooves on the surface of the optoelectronic chip and controlling the distribution of the grooves, the present invention embeds the protective sheet within the optoelectronic chip. This prevents relative displacement during polishing, improving reliability, and reduces stress at single points, preventing damage to the optoelectronic chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of a processing flow of a method for processing an end face of an optoelectronic chip;

[0033] Figure 2 is a top view of the optoelectronic chip;

[0034] Figure 3 A top view of the protective sheet.

[0035] In the figure, 1 is an optoelectronic chip; 11 is a bump; 12 is a groove; 2 is a protective sheet; 21 is a raised structure; 3 is an adhesive; 4 is the processed optoelectronic chip; and 5 is a preset clamping area. DETAILED DESCRIPTION

[0036] To facilitate understanding of the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments or examples and are not intended to limit the present invention.

[0038] In order to prevent relative displacement between the protective sheet and the optoelectronic chip during end face processing, a groove can be opened on the surface of the optoelectronic chip, and a raised structure corresponding to the groove is provided on the protective sheet. Then, the raised structure on the protective sheet is embedded in the groove on the surface of the optoelectronic chip, so that the protective sheet and the optoelectronic chip are mechanically engaged to prevent displacement. However, this method often causes damage to the optoelectronic chip during the processing process.

[0039] Further research revealed that the damage to optoelectronic chips during processing was caused by high stress at a single point. Figure 1 、 Figure 2 and Figure 3 As shown, the end face processing method of the optoelectronic chip provided by the present invention includes the following steps:

[0040] S1, forming a plurality of grooves 12 on the surface of the optoelectronic chip 1 having the bumps 11, wherein the grooves 12 are axially symmetrically distributed along any central axis of the optoelectronic chip 1, and one groove 12 is formed every 300 μm-1000 μm on the central axis of the optoelectronic chip 1, at least four grooves 12 are formed in the predetermined clamping area 5, and at least four grooves 12 are formed in the non-clamping area;

[0041] S2, covering the surface of the optoelectronic chip 1 having the bumps 11 with a protective sheet 2, wherein the surface of the protective sheet 2 has a raised structure 21 that can be matched with the groove 12 in the optoelectronic chip 1, and the height of the raised structure 21 is greater than the sum of the depth of the groove 12 and the height of the bump 11, using the raised structure 21 to be embedded in the groove 12 to fix the optoelectronic chip 1 and the protective sheet 2, and filling an adhesive 3 between the optoelectronic chip 1 and the protective sheet 2 to form a composite structure;

[0042] S3, clamping the composite structure with a fixture, with the clamping position of the fixture corresponding to the preset clamping area 5 of the optoelectronic chip 1, and then grinding and polishing the end surface of the optoelectronic chip 1;

[0043] S4 , after the grinding and polishing process is completed, the protective sheet 2 and the adhesive 3 are removed to obtain the processed optoelectronic chip 4 .

[0044] Therefore, when the grooves 12 are formed on the surface of the optoelectronic chip 1 having the bumps 11 , the present invention can reduce stress at a single point by controlling the distribution of the grooves 12 , thereby preventing the optoelectronic chip 1 from being damaged.

[0045] It is understood that the shape of the optoelectronic chip 1 is not limited, such as circular, square, rectangular, etc., and can be customized as needed. Figure 2 As shown, when the optoelectronic chip 1 is rectangular, it has two horizontal and vertical central axes, and the grooves 12 can be axially symmetrically distributed along the horizontal central axis of the optoelectronic chip 1 or axially symmetrically distributed along the vertical central axis of the optoelectronic chip 1 .

[0046] Optionally, when making grooves 12 on the central axis of the optoelectronic chip 1, when one groove 12 is made every 300μm-1000μm, the distance between two adjacent grooves 12 can be the same or different. When the distances are different, they can be increasing successively, decreasing successively, or changing irregularly, and can be controlled between 300μm-1000μm. Furthermore, it is preferred to make one groove 12 every 600μm-800μm.

[0047] It should be noted that the preset clamping area 5 and the non-clamping area include a central axis, and the number of grooves 12 made in the preset clamping area 5 and the non-clamping area described in the present invention does not include the grooves 12 on the central axis, that is, the number of grooves 12 on the non-central axis is at least 8 or more.

[0048] Optionally, when forming the grooves 12 in the predetermined clamping area 5, the number of grooves 12 can be 4, 6, 8, 10, etc., more preferably 4-6. Furthermore, the vertical distance between the grooves 12 in the predetermined clamping area 5 and the edge of the optoelectronic chip 1 is controlled to be greater than or equal to 400 μm, and the vertical distance from the central axis is controlled to be greater than or equal to 300 μm. This not only further reduces stress at a single point to prevent damage to the optoelectronic chip 1, but also ensures that the protective sheet 2 is more reliably fixed to the optoelectronic chip 1.

[0049] Similarly, when forming the grooves 12 in the non-clamping area, the number of grooves 12 can be 4, 8, 10, 12, etc., with 8 to 10 being more preferred. Furthermore, further controlling the vertical distance between the grooves 12 in the non-clamping area and the edge of the optoelectronic chip 1 to be greater than or equal to 400 μm, and the vertical distance from the central axis to be greater than or equal to 300 μm, not only further reduces stress at a single point to prevent damage to the optoelectronic chip 1, but also ensures more reliable fixation of the protective sheet 2 to the optoelectronic chip 1.

[0050] It can be understood that within the preset clamping area 5, the vertical distances between the multiple grooves 12 located on the same side of the central axis and the central axis can be the same or different, and the vertical distances to the edge of the optoelectronic chip 1 can be the same or different; similarly, in the non-clamping area, the vertical distances between the multiple grooves 12 located on the same side of the central axis and the central axis can be the same or different, and the vertical distances to the edge of the optoelectronic chip 1 can be the same or different.

[0051] In order to further reduce the stress at a single point position to prevent damage to the optoelectronic chip 1, and at the same time further improve the fixing effect of the protective sheet 2 and the optoelectronic chip 1, in the preset clamping area 5, the distance between the grooves 12 is greater than or equal to 400 μm, and / or, in the non-clamping area, the distance between the grooves 12 is greater than or equal to 400 μm, and / or, the distance between the grooves in the preset clamping area and the grooves in the non-clamping area is greater than or equal to 400 μm. Furthermore, the distances between the grooves 12 on non-central axes are all greater than or equal to 400 μm, and the distances between different grooves 12 may be the same or different.

[0052] It can be understood that in order to make the grinding and polishing process more stable, the preset clamping area 5 is generally located in the central area of ​​the optoelectronic chip 1. At this time, the areas on both sides of the preset clamping area 5 in the optoelectronic chip 1 are non-clamping areas, and preferably, grooves 12 are made in the non-clamping areas.

[0053] When making a groove 12 on the surface of the optoelectronic chip 1, the shape of the groove 12 can be a cylinder, a triangular prism or a quadrangular prism, etc. In order to reduce the difficulty of making the groove 12 and the difficulty of assembling the groove 12 and the protruding structure 21, the shape of the groove 12 is preferably a cylinder. Correspondingly, the shape of the protruding structure 21 is also a cylinder, and the size of the protruding structure 21 is not larger than the size of the groove 12.

[0054] Furthermore, in order to make the protruding structure 21 on the protective sheet 2 more easily embedded in the groove 12 of the optoelectronic chip 1, and to ensure that the optoelectronic chip 1 and the protective sheet 2 are more stable after embedding and do not undergo relative displacement, the depth of the groove 12 is preferably 80μm-300μm. At the same time, the maximum physical size (MMS) of the groove 12 is controlled to be greater than or equal to 100μm, and further preferably 120μm-200μm. For example, when the groove 12 is a cylinder, the diameter of the groove 12 is greater than or equal to 100μm. Such a setting can increase the contact area between the protruding structure 21 and the groove 12, and further reduce the single-point stress.

[0055] Optionally, the sum of the depth of the groove 12 and the height of the bump 11 differs from the height of the protruding structure 21 by 50 μm-100 μm, so that the adhesive 3 filled between the optoelectronic chip 1 and the protective sheet 2 can effectively buffer the pressure during clamping or polishing, thereby avoiding damage to the bump 11, and also avoiding waste caused by excessive use of the adhesive 3.

[0056] It should be noted that when filling the adhesive 3, the adhesive 3 can cover the bumps 11 but not completely fill the gap between the optoelectronic chip 1 and the protective sheet 2, or it can completely fill the gap between the optoelectronic chip 1 and the protective sheet 2. In the present invention, the adhesive 3 preferably completely fills the gap between the optoelectronic chip 1 and the protective sheet 2.

[0057] At the same time, when filling the adhesive 3 between the optoelectronic chip 1 and the protective sheet 2, the filling method and order are not limited. The adhesive 3 can be first applied to the non-groove 12 area of ​​the surface of the optoelectronic chip 1 with the bump 11, and then the protruding structure 21 of the protective sheet 2 is embedded in the groove 12 of the optoelectronic chip 1 to form the composite structure; the adhesive 3 can also be applied to the surface of the protective sheet 2 with the protruding structure 21, and then the protruding structure 21 of the protective sheet 2 is embedded in the groove 12 of the optoelectronic chip 1 to form the composite structure; the protruding structure 21 of the protective sheet 2 can also be embedded in the groove 12 of the optoelectronic chip 1, and then the adhesive 3 can be injected between the optoelectronic chip 1 and the protective sheet 2 to form the composite structure.

[0058] To prevent solvents or impurities from penetrating and contaminating the bumps 11 during the polishing process, the adhesive 3 selected in the present invention does not react with acidic or alkaline substances. Furthermore, to facilitate removal of the adhesive 3 and protective sheet 2 after the polishing process, the adhesive 3 is made of a material that can be removed with conventional cleaning agents, including one or more of paraffin wax, epoxy resin, UV adhesive, or photoresist.

[0059] To ensure that the protective sheet 2 does not deform when clamped by a fixture, the Young's modulus of the protective sheet 2 is preferably greater than or equal to 70 GPa, and the thickness of the protective sheet 2 is greater than or equal to 1 mm. Furthermore, the protective sheet 2 is selected from silicon oxide, silicon, silicon nitride, or glass.

[0060] It can be understood that the size of the protective sheet 2 can be greater than, less than or equal to the size of the optoelectronic chip 1, but it needs to completely cover the bumps 11 on the optoelectronic chip 1 to protect the bumps 11. Preferably, the size of the protective sheet 2 is the same as the size of the optoelectronic chip 1.

[0061] In addition, the protective sheet 2 and the protruding structure 21 may be an integral structure or a non-integrated structure. In the non-integrated structure, the material of the protruding structure 21 may be the same as or different from that of the protective sheet 2, and may be selected from one or more of silicon oxide, silicon, silicon nitride, metal, or glass.

[0062] It can be understood that when a clamp is used to clamp the composite structure in the present invention, the clamping position of the clamp corresponds to the preset clamping area 5 of the optoelectronic chip 1, which means that the clamp does not directly contact the preset clamping area 5 of the optoelectronic chip 1, but is clamped on the protective sheet 2 corresponding to the preset clamping area 5 and the optoelectronic chip 1.

[0063] It should be noted that when the end surface of the optoelectronic chip 1 is subjected to grinding and polishing, the grinding and polishing process is carried out by grinding or polishing, etc., which will not be elaborated in detail in the present invention.

[0064] After the polishing process is completed, the type of cleaning agent for removing the adhesive 3 can be selected according to the composition of the adhesive 3. For example, when the adhesive 3 is paraffin, alcohol can be used for wiping to obtain the processed optoelectronic chip 4.

[0065] Therefore, in the end face processing method of the present invention, the protective sheet 2, the adhesive 3, and the optoelectronic chip 1 form a composite structure. This prevents direct contact between the bumps 11 of the optoelectronic chip 1 and the fixture or the protective sheet 2 during grinding and polishing, fully protecting the bumps 11 of the optoelectronic chip 1 from damage. Furthermore, by forming the grooves 12 on the surface of the optoelectronic chip 1 and controlling the distribution of the grooves 12, the protective sheet 2 is embedded in the optoelectronic chip 1. This prevents relative displacement during grinding and polishing, resulting in high reliability. It also reduces stress at single points, preventing damage to the optoelectronic chip 1.

[0066] After testing, it was found that when the grooves 12 were made by the method of the present invention, the optoelectronic chip 1 was not damaged after the grinding and polishing treatment. However, when the distribution of the grooves 12 was slightly changed, for example:

[0067] (1) When no groove 12 is made on the central axis, or when one groove 12 is made every 1200 μm on the central axis, or when one groove 12 is made every 1500 μm on the central axis, or when one groove 12 is made every 200 μm on the central axis, the optoelectronic chip 1 is damaged after being polished;

[0068] (2) The grooves 12 in the preset clamping area are symmetrical along the central axis, but there are only two of them. Alternatively, the number of grooves 12 in the preset clamping area is five, resulting in asymmetry along the central axis. Alternatively, when the number of grooves 12 in the preset clamping area is four, and there are two grooves 12 on both sides of the central axis, but the distances between the grooves 12 on both sides of the central axis are different, resulting in asymmetry along the central axis, the optoelectronic chip 1 is damaged after being polished.

[0069] (3) The grooves 12 in the non-clamping area are symmetrical along the central axis, but there are only two of them. Alternatively, the number of the grooves 12 in the non-clamping area is five, resulting in asymmetry along the central axis. Alternatively, when the number of the grooves 12 in the non-clamping area is four, and there are two grooves 12 on both sides of the central axis, but the distances between the grooves 12 on both sides of the central axis and the central axis are different, resulting in asymmetry along the central axis, the optoelectronic chip 1 is damaged after being polished.

[0070] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for processing the end face of an optoelectronic chip, characterized in that: The following steps are involved: Making a plurality of grooves on the surface of the optoelectronic chip having the bumps, wherein the grooves are axially symmetrically distributed along any central axis of the optoelectronic chip, and one groove is made every 300 μm to 1000 μm on the central axis of the optoelectronic chip, at least four grooves are made in a preset clamping area, and at least four grooves are made in a non-clamping area; Covering the surface of the optoelectronic chip having the bumps with a protective sheet, wherein the surface of the protective sheet has a raised structure that can be matched with the groove in the optoelectronic chip, and the height of the raised structure is greater than the sum of the depth of the groove and the height of the bump, the raised structure is embedded in the groove to fix the optoelectronic chip and the protective sheet, and an adhesive is filled between the optoelectronic chip and the protective sheet to form a composite structure; The composite structure is clamped by a fixture, wherein the clamping position of the fixture corresponds to a preset clamping area of ​​the optoelectronic chip, and then the end surface of the optoelectronic chip is ground and polished; After the grinding and polishing process is completed, the protective sheet and the adhesive are removed to obtain a processed optoelectronic chip.

2. The method for processing the end face of an optoelectronic chip according to claim 1, wherein: On the central axis of the optoelectronic chip, a groove is made every 600 μm to 800 μm; and / or, making 4-6 grooves in the predetermined clamping area; And / or, 8-10 grooves are made in the non-clamping area.

3. The method for processing the end face of an optoelectronic chip according to claim 1, wherein: The vertical distance between the groove in the preset clamping area and the edge of the optoelectronic chip is greater than or equal to 400 μm; and / or, a vertical distance between the groove in the non-clamping area and the edge of the optoelectronic chip is greater than or equal to 400 μm; And / or, a vertical distance between the groove in the preset clamping area and the central axis is greater than or equal to 300 μm; And / or, a vertical distance between the groove in the non-clamping area and the central axis is greater than or equal to 300 μm.

4. The method for processing the end face of an optoelectronic chip according to claim 1, wherein: In the preset clamping area, the distance between the grooves is greater than or equal to 400 μm; and / or, in the non-clamping area, the distance between the grooves is greater than or equal to 400 μm; And / or, the distance between the groove in the preset clamping area and the groove in the non-clamping area is greater than or equal to 400 μm.

5. The method for processing the end face of an optoelectronic chip according to claim 1, wherein: The optoelectronic chip has two non-clamping areas, and the groove is formed in each non-clamping area.

6. The method for processing the end face of an optoelectronic chip according to claim 1, wherein: The depth of the groove is 80 μm-300 μm; And / or, the maximum physical dimension of the groove is greater than or equal to 100 μm.

7. The method for processing the end face of an optoelectronic chip according to claim 1, wherein: The sum of the depth of the groove and the height of the protrusion differs from the height of the protrusion structure by 50 μm to 100 μm.

8. The method for processing the end face of an optoelectronic chip according to claim 1, wherein: The adhesive completely fills the gap between the optoelectronic chip and the protective sheet.

9. The method for processing the end face of an optoelectronic chip according to claim 1, wherein: The Young's modulus of the protective sheet is greater than or equal to 70 GPa; And / or, the thickness of the protective sheet is greater than or equal to 1 mm; And / or, the adhesive does not react with acidic substances and alkaline substances.

10. The method for processing the end face of an optoelectronic chip according to claim 9, wherein: The protective sheet is selected from a silicon oxide sheet, a silicon sheet, a silicon nitride sheet or a glass sheet; And / or, the adhesive is selected from one or more of paraffin wax, epoxy resin, UV adhesive or photoresist.

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