Packaging and polishing method for optical chip

Abstract

The invention discloses a packaging and polishing method for an optical chip, which comprises the following steps: placing a glass body with uniform thickness in a photosensitive area of the optical chip, and manufacturing a protective sheet capable of covering the upper end surface of the glass body in a packaging and polishing process, so that the protective sheet has a set thickness and can be removed after being polished and thinned. Furthermore, a protective cap provided with an inner cavity with a downward opening and used for sleeving the glass body is manufactured, and a protective piece is arranged at the top of the inner cavity and attached to the top wall of the inner cavity. Furthermore, the depth of the inner cavity is set, and the standard is that when the glass body is arranged in the inner cavity of the protective cap in a sleeved mode and the upper surface of the glass body is attached to the protective piece on the top of the inner cavity, the bottom end face of the protective cap is attached to the base plate. The polishing device has the advantages that the upper end face of the glass body is not damaged in the polishing process, so that the upper end face of the polished glass body is smooth and clean; and it can be guaranteed that the glass body does not incline in the packaging and polishing process.

Description

Technical Field

[0001] The invention relates to a packaging and polishing method for an optical chip, and belongs to the technical field of chip packaging. Background Art

[0002] With the continuous development of chip technology, there are more and more high-pixel camera module products. The current packaging technology cannot meet the process requirements of current high-end imaging products in terms of the height of the camera module and the flatness of the optical performance. At the same time, during the packaging process, the different thermal expansion coefficients during the heating and curing process cause the chip to deform, reducing reliability.

[0003] In the existing technology, a photosensitive area is set on the surface of the optical chip, glass is placed on it, and then open-molding is performed through plastic packaging material. Not only does it use a large amount of glue and is costly, but it may also cause the chip and glass surfaces to be uneven, affecting optical reflection and refraction, etc., and different mechanical stresses and thermal expansion coefficients may cause warping during the packaging process. In addition, the surface needs to be ground and flattened after plastic packaging. This process may cause the coating on the glass surface to be damaged, or even scratch the glass, affecting the light transmission performance.

[0004] The patent document with application number 202310801893.9 discloses an LED chip packaging structure and a method for preparing the LED chip packaging structure, which relates to the field of chip packaging technology. The LED chip packaging structure uses a blocking shading layer to cover a plurality of pixel LED chips, wherein the light-emitting side of the pixel LED chip is exposed on one side of the blocking shading layer, and a re-circuit distribution layer is provided on the other side of the blocking shading layer, wherein the blocking shading layer is used to block the crosstalk light between adjacent pixel LED chips. Compared with the prior art, the present invention can cover the pixel LED chip by using an opaque blocking shading layer. When actually emitting light, the blocking shading layer can play a side shading role, blocking the crosstalk light between adjacent pixel LED chips, and improving the luminous brightness and luminous uniformity.

[0005] The technical solution provided by this patent replaces the substrate structure in conventional technology by re-setting the circuit distribution layer and the solder mask layer, and sets a certain thickness of the enclosure shading layer on the periphery of the LED chip. The enclosure shading layer forms a hole in the photosensitive area on the front of the LED chip, and a transparent body is filled in the hole. Although it can block the crosstalk light between adjacent pixel LED chips and improve the brightness and uniformity of the light, the process of re-routing the circuit and setting the solder mask layer is extremely complicated. In addition, the subsequent packaging structure (setting a certain thickness of the enclosure shading layer on the periphery of the LED chip, the enclosure shading layer forms a hole in the photosensitive area on the front of the LED chip, and a transparent body is filled in the hole) further increases the difficulty of applying this technical solution. Summary of the invention

[0006] The technical problem to be solved by the present invention is: how to avoid scratches on the glass surface during grinding while still placing glass with good light transmittance in the photosensitive area without re-laying the circuits and setting the solder mask layer.

[0007] In view of the above problems, the technical solution proposed by the present invention is: A packaging and polishing method for an optical chip includes placing a glass body with uniform thickness on a photosensitive area of ​​the optical chip, and also includes making a protective sheet that can cover the upper end surface of the glass body during the packaging and polishing process, so that the protective sheet has a set thickness and can be removed after being polished and thinned.

[0008] Furthermore, it also includes making a protective cap with an inner cavity opening downward for housing the vitreous body, placing the protective plate on the top of the inner cavity and making it stick to the top wall of the inner cavity.

[0009] Furthermore, the depth of the inner cavity is set, and the standard is that when the vitreous body is inserted into the inner cavity of the protective cap and the upper surface of the vitreous body is in contact with the protective sheet at the top of the inner cavity, the bottom end surface of the protective cap is close to the base plate.

[0010] The above packaging polishing method comprises the following steps: S1. Place the glass body on the photosensitive area of ​​the optical chip on the substrate after all the optical chip welding and wire bonding is completed; S2, applying glue on the periphery of the photosensitive area, and then pressing the protective cap downward from the top of the glass body, so that the glass body enters the inner cavity until the bottom end surface of the protective cap adheres to the glue on the substrate, so that the protective cap is fixed by the glue and the glass body is limited by the protective cap; S3, placing the substrate on the lower mold, pressing the upper mold on the top surface of the protective cap, so that the protective sheet inside the protective cap presses the glass body tightly to prevent the glass body from tilting during the sealing and polishing; S4, injecting glue and packaging between the upper mold and the lower mold; S5, cooling and removing the upper mold; S6, grinding until the top of the protective cap is worn off to expose the protective plate; S7. Remove the guard.

[0011] Furthermore, the method further includes setting the diameter of the guard plate to be equal to the diameter of the inner cavity of the protective cap, so that the outer periphery of the guard plate is closely attached to the wall of the inner cavity to prevent the guard plate from falling out during grinding in step S6.

[0012] Furthermore, it also includes cutting an oblique cut downward on the top surface of the guard plate, and when removing the guard plate in step S7, a rod is inserted into the cut to pry the guard plate out of the guard cap 34.

[0013] Furthermore, the vertical depth of the cutout is smaller than the thickness of the guard plate.

[0014] Furthermore, there is a gap between the inner wall of the inner cavity of the protective cap and the outer peripheral surface of the vitreous body, and the gap spacing is less than 0.05 mm.

[0015] Furthermore, it also includes opening a plurality of glue-permeable windows on the cap body of the protective cap, so that during the glue injection and packaging in step S4, the glue can pass through the glue-permeable windows to bond the glass body.

[0016] Furthermore, the height of the glue-permeable window is lower than the end surface of the glass body. Beneficial Effects

[0017] 1. It can ensure that the upper end surface of the glass body is not damaged during the grinding process, so as to ensure that the upper end surface of the glass body is smooth after grinding; 2. It can ensure that the glass body is not skewed during the packaging and grinding process; 3. Simple setting and easy operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A side view schematic diagram of a plurality of chips being welded in rows and columns on a substrate before glue injection packaging; Figure 2 for Figure 1 A partial schematic diagram of Figure 3 It is a cross-sectional schematic diagram of putting the protective cap on the glass body and bonding it to the substrate before packaging; Figure 4 for Figure 3 Schematic diagram of the decomposition; Figure 5 A three-dimensional schematic diagram of the separation of the protective cap, protective plate and vitreous body; Figure 6 is a schematic cross-sectional view of a guard plate; Figure 7 A schematic cross-sectional view of all chips on a substrate being packaged in a mold cavity after being equipped with glass bodies, protective sheets and protective caps; Figure 8 Schematic diagram of the cross section after the injection molding and demolding; Fig. 9 A schematic cross-sectional view of a chip after polishing but without the protective sheet removed; Fig.10 A schematic cross-sectional view of a chip after polishing with the guard removed.

[0019] In the figure: 1, substrate; 2, optical chip; 201, photosensitive area; 202, electrical conductor; 3, glass body; 4, protective plate; 401, incision; 5, protective cap; 501, inner cavity; 502, glue-permeable window; 6, sealing glue; 7, upper mold; 8, lower mold. DETAILED DESCRIPTION

[0020] like Figure 1 , 2As shown, the optical chip 2 involved in the present invention needs to be welded and connected to the substrate 1 through the bottom welding ball. The upper surface of the optical chip 2 has a photosensitive area 201, which needs to be well protected. There are also many circuits on the upper surface of the optical chip 2 outside the photosensitive area 201 that need to be connected to the substrate through the electrical conductor 202, and the connection method is also through welding. The optical chip 2 that has been welded needs to be uniformly sealed with glue to ensure the stability of the connection structure of the optical chip 2, substrate 1 and electrical conductor 202 and the insulation of the electrical conductor. In order to facilitate processing and improve production efficiency, generally a substrate 1 will be loaded with multiple optical chips 2 in rows and columns at the same time, and then uniformly packaged, polished, and cut.

[0021] The present invention will be further described below in conjunction with embodiments and drawings: Embodiment 1

[0022] like Figure 3 , 4 As shown in Figure 5, a packaging and polishing method for an optical chip includes placing a glass body 3 of uniform thickness in the photosensitive area 201 of the optical chip, and also includes making a protective sheet 4 that can cover the upper end surface of the glass body 3 during the packaging and polishing process, so that the protective sheet 4 has a set thickness and can be removed after being polished and thinned. Before packaging, the protective sheet 4 is placed on the upper end surface of the glass body 3, and then they are packaged together in the mold by injection. After demolding, the surface of the entire package is polished, and finally the protective sheet 4 is removed. Since the surface of the glass body 3 is protected by the protective sheet 4, the protective sheet 4 will only be thinned a little within the set polishing depth, and the upper end surface of the glass body 3 cannot be damaged. In this way, after the polishing is completed, the protective sheet 4 is removed, and the upper end surface of the glass body 3 can be smooth and intact.

[0023] Furthermore, the above-mentioned packaging and polishing method also includes: making a protective cap 5 with an inner cavity 501 opening downward for fitting the glass body 3, placing the protective plate 4 on the top of the inner cavity 501 and making it abut against the top wall of the inner cavity 501; setting the depth of the inner cavity 501, the standard is that when the glass body 3 is fitted into the inner cavity 501 of the protective cap 5, the upper surface of the glass body 3 is abutted against the protective plate 4 on the top of the inner cavity 501, and the bottom end surface of the protective cap 5 is close to the substrate 1.

[0024] like Figure 3 , 7 As shown in FIGS. 8, 9 and 10, packaging and polishing the optical chip 2 using the protective sheet 4 and the protective cap 5 includes the following steps: S1, placing the glass body 3 on the photosensitive area of ​​the optical chip 2 on the substrate 1 after all the optical chips 2 are welded and wired; S2, applying glue on the periphery of the photosensitive area 201, and then pressing the protective cap 5 downward from the top of the glass body 3, so that the glass body 3 enters the inner cavity 501 until the bottom end surface of the protective cap 5 adheres to the glue on the substrate 1, so that the protective cap 5 is fixed by the glue, and the glass body 3 is limited by the protective cap 5; S3, placing the substrate 1 on the lower mold 8, pressing the upper mold 7 on the top surface of the protective cap 5, so that the protective sheet 4 in the protective cap 5 presses the glass body 3 tightly to prevent the glass body 3 from being skewed during the sealing and polishing; S4, injecting glue and packaging between the upper mold 7 and the lower mold 8; S5, cooling, removing the upper mold 7 and the lower mold; S6, grinding until the top of the protective cap 5 is ground off to expose the protective plate 4; S7. Remove the guard.

[0025] It can be seen from the above embodiment that the protective plate 4 is covered by the protective cap 5, and the packaging process does not cause the protective plate 4 to adhere to the protective cap 5 and the glass body 3. After the top of the protective cap 5 is polished off to expose the protective plate 4, the protective plate 4 can be easily removed.

[0026] The above method also includes setting the diameter of the protective plate 4 to be equal to the diameter of the inner cavity 501 of the protective cap 5, so that the outer periphery of the protective plate is closely attached to the wall of the inner cavity 501, thereby preventing the protective plate from falling out during polishing in step S6, and also preventing the scratched glass from moving on the surface of the glass body 3 during polishing.

[0027] like Figure 3 , 4 As shown in Figures 6 and 9, the method further includes cutting an oblique cut 401 downward on the top surface of the guard plate 4. When removing the guard plate 4 in step S7, a rod can be inserted into the cut 401 to pry the guard plate 4 out of the protective cap 34, so that the guard plate 4 cannot fall out by itself during grinding and can be easily removed after grinding is completed.

[0028] Furthermore, the vertical depth of the cutout 401 is made smaller than the thickness of the guard plate 4 , which actually means that the cutout 401 is not connected to the bottom of the guard plate 4 . Thus, when the rod is inserted into the cutout 401 , the rod is prevented from contacting the glass body 3 , thereby protecting the glass body 3 .

[0029] like Figure 3 , 4 As shown, there is a gap between the inner wall of the protective cap cavity 501 and the outer peripheral surface of the vitreous body 3, and the gap spacing is less than 0.05mm. In this way, the protective cap 5 can be smoothly put on the vitreous body 3, and the movement of the vitreous body 3 in the protective cap can be effectively restricted.

[0030] like Figure 3 , 4As shown in FIG. 5 , the method further includes opening a plurality of glue-permeable windows 502 on the body of the protective cap 5. During the glue injection and packaging in step S4, the glue can pass through the glue-permeable windows 502 to bond the glass body 3, so that the glass body 3 is firmly fixed by the sealing glue, thereby ensuring the integrity of the entire packaging structure.

[0031] The height of the glue-permeable window 502 is lower than the end face of the glass body 3, thereby ensuring that the end face of the glass body 3 will not be immersed in the sealing glue 6, which can not only ensure that the guard plate 4 is not stuck, but also ensure the cleanliness of the cross section of the glass body 3, and there is no need to clean up the residual glue later. Embodiment 2

[0032] The difference between this and steps S1 and S2 of embodiment 1 is that the glass body 3 can be placed in the protective cap 5 first, and then the protective cap 5 and the glass body 3 are pinched and buckled on the substrate 1, so that the glass body 3 is located in the photosensitive area 201, and the bottom end surface of the protective cap 5 is adhered to the glue on the substrate 1.

[0033] This requires that the protective cap 5 is made of a flexible material that can be pinched and deformed.

[0034] The above embodiments are only used to more clearly describe the present invention and cannot be regarded as limiting the protection scope of the present invention. Any modifications in equivalent forms should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for packaging and polishing an optical chip, comprising placing a glass body (3) of uniform thickness on a photosensitive area (201) of an optical chip (2), characterized in that: The method also includes manufacturing a protective sheet (4) capable of covering the upper end surface of the glass body (3) during the packaging and polishing process, so that the protective sheet (4) has a set thickness and can be removed after being polished and thinned. Before packaging, the protective sheet (4) is placed on the upper end surface of the glass body (3), and then the two are packaged together in a mold by injecting glue. After demolding, the surface of the entire packaging body is polished, and finally the protective sheet (4) is removed.

2. The method for packaging and polishing an optical chip according to claim 1, characterized in that: The method also includes manufacturing a protective cap (5) having an inner cavity (501) with an opening downward for housing the vitreous body (3), placing a protective plate (4) on the top of the inner cavity (501) and making it adhere to the top wall of the inner cavity (501).

3. The packaging and polishing method of an optical chip according to claim 2, characterized in that: The depth of the inner cavity (501) is also set, and the standard is that when the glass body (3) is inserted into the inner cavity (501) of the protective cap (5), the upper surface of the glass body (3) is in contact with the protective sheet (4) at the top of the inner cavity (501), and the bottom end surface of the protective cap (5) is close to the base plate (1).

4. The method for packaging and polishing an optical chip according to claim 3, characterized in that The steps include: S1, placing a glass body (3) on the photosensitive area of ​​the optical chip (2) on the substrate (1) on which all the optical chips (2) have been welded and wired; S2, applying glue on the periphery of the photosensitive area (201), and then pressing the protective cap (5) downward from the top of the glass body (3), so that the glass body (3) enters the inner cavity (501) until the bottom end surface of the protective cap (5) adheres to the glue on the substrate (1), so that the protective cap (5) is fixed by the glue, and the glass body (3) is limited by the protective cap (5); S3, placing the substrate (1) on the lower mold (8), pressing the upper mold (7) onto the top surface of the protective cap (5), so that the protective sheet (4) inside the protective cap (5) presses the glass body (3) tightly to prevent the glass body (3) from tilting during the sealing and polishing; S4, injecting glue between the upper mold (7) and the lower mold (8) for packaging; S5, cooling, and removing the upper mold (7); S6, grinding until the top of the protective cap (5) is ground off to expose the protective plate (4); S7. Remove the guard.

5. The packaging and polishing method of an optical chip according to claim 4, characterized in that: The method further includes setting the diameter of the protective plate (4) to be equal to the diameter of the inner cavity (501) of the protective cap (5), so that the outer periphery of the protective plate is closely attached to the wall of the inner cavity (501), thereby preventing the protective plate from falling out during grinding in step S6.

6. The method for packaging and polishing an optical chip according to claim 4, characterized in that: The method further comprises cutting an oblique cut (401) downward on the top surface of the guard plate (4), and when removing the guard plate (4) in step S7, inserting a rod into the cut (401) to pry the guard plate (4) out of the guard cap 34.

7. The packaging and polishing method of an optical chip according to claim 6, characterized in that: The vertical depth of the cutout (401) is smaller than the thickness of the guard plate (4).

8. The method for packaging and polishing an optical chip according to claim 4, characterized in that: There is a gap between the inner wall of the protective cap inner cavity (501) and the outer peripheral surface of the glass body (3), and the gap spacing is less than 0.05 mm.

9. The method for packaging and polishing an optical chip according to claim 4, characterized in that: The method further comprises opening a plurality of glue-permeable windows (502) on the body of the protective cap (5), so that during the glue injection and packaging in step S4, the glue can pass through the glue-permeable windows (502) to bond the glass body (3).

10. The optical chip packaging and polishing method according to claim 9, characterized in that: The height of the plastic-transmissive window (502) is lower than the end surface of the glass body (3).

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