Manufacturing method of QFN (Quad Flat No-lead) product based on water-soluble film process
By attaching a water sol sheet on the surface of the glass sheet and injecting plastic sealing colloids at high temperatures, the problem of existing exposed glass products overflowing plastic sealing materials and glass lobes during the plastic sealing process is solved, and a higher product pass rate and processing safety are achieved.
Patent Information
- Application Number
- CN202411710203.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-03-11
AI Technical Summary
During the plastic sealing process, existing exposed glass products can easily cause plastic sealing material to overflow on the upper surface of the glass, and the glass is prone to tilt or lobes when placed, which is at a high risk.
The QFN product production method based on the water sol sheet process is adopted. By attaching the water sol sheet on the surface of the glass sheet and injecting plastic sealing colloids at high temperature, the water sol sheet is then cleaned and removed to expose the glass sheet to ensure that the glass surface is not covered by the plastic sealing colloids.
It effectively avoids the problem of plastic sealing material overflowing on the glass surface, reduces the risk of glass lobes, and improves the product pass rate and the safety of the processing process.
Smart Images
Figure CN119601504A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of chip packaging, in particular to a method for manufacturing a QFN product based on a water-soluble gel sheet process. Background Art
[0002] In the packaging industry, the glass of optical products needs to be completely exposed so that the optical chip under the glass can fully transmit light and not affect normal use. However, existing exposed glass products directly plastic-seal the exposed glass, which may cause overflow of plastic-seal material on the upper surface of the glass. At the same time, the glass is prone to tilt when placed, and there is a high risk of glass cracking when the plastic-seal mold is closed. Summary of the invention
[0003] In order to overcome the deficiencies of the prior art, the present invention provides a method for manufacturing a QFN product based on a water-soluble gel sheet process.
[0004] To achieve the above purpose, a method for manufacturing QFN products based on a water-soluble film process is designed, comprising the following steps: S1, grinding: grinding the wafer to a set thickness; S2, cutting: stick a layer of film on the back of the wafer, and cut the wafer along the cutting groove to obtain several single chips; S3, chip loading: attach the chip to the carrier frame using conductive adhesive; S4, wire bonding: bonding wires between the chip and the carrier frame to achieve electrical connection; S5, attaching a glass sheet and a hydrosol sheet on the surface of the chip; S6, film pasting: paste a layer of high temperature resistant film on the back of the load-bearing frame; S7, plastic sealing: put the supporting frame into the mold cavity of the mold, and inject the plastic sealing colloid at a high temperature of 175℃; S8, baking: maintaining a high temperature of 175°C for 6 hours until the plastic encapsulation colloid is completely cured; S9, film removal: remove the high temperature resistant film on the back of the carrying frame by heating at 100°C, exposing the guide pins and the base heat sink on the back of the carrying frame; S10, cleaning the hydrosol sheet: cleaning with deionized water at 60° C. for 20 minutes to remove the hydrosol sheet on the surface of the glass sheet, and then drying at high temperature to expose the glass sheet; The specific method of step S5 is as follows: S51, attaching an adhesive film to the back of the entire glass sheet; S52, attaching a hydrosol sheet to the front of the entire glass sheet, heating the vacuum platform to 80±5°C, attaching the hydrosol sheet to the glass sheet, the vacuum degree is 10kpa, and the roller pressure is 20N; S53, separating the glass sheets into required sizes by cutting; S54, after cutting, UV is removed by 200mj / cm2 energy; S55, attaching a glass sheet to the surface of the chip.
[0005] In the step S51, the thickness of the adhesive film is 20 um.
[0006] In the step S5, the thickness of the hydrosol film is 20 um.
[0007] In the step S7, the surface of the contact area in the mold cavity with the hydrosol sheet is mirror-finished, and the roughness Ra is 0.06 um.
[0008] In the step S7, the center value of the mold cavity thickness is controlled within ±5um.
[0009] During the plastic sealing in step S7, the water-soluble adhesive sheet is not plastic sealed.
[0010] In the step S3, baking is performed after mounting, and the conductive adhesive forms a baked adhesive film to fix the chip on the supporting frame.
[0011] The following steps are also included: S11, electroplating: tinning the guide pins on the back of the load-bearing frame, and the heat sinks on the front and back of the load-bearing frame to facilitate later welding; S12, stamping: laser engraved silk screen corresponding to product information; S13, cutting: dividing the whole frame into single products.
[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. Use the elastic deformation ability of the water-soluble film to solve the problem of pressure damage caused by contact between the glass sheet and the mold surface.
[0013] 2. Make use of the bonding and wrapping properties of the water-soluble adhesive sheet and the glass to ensure that the plastic sealant cannot cover the surface of the glass sheet, thus solving the problem of glue overflow.
[0014] 3. Through the special design of the molding die, the hydrosol film is used to ensure the flatness and accuracy of the glass appearance.
[0015] 4. Use hot water to wash away the hydrosol and then dry it to ensure that the glass is completely transparent, which improves the product's qualification rate and reduces the damage rate during product processing. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a schematic diagram of step S5 of the present invention.
[0017] Figure 2 It is a flow chart of the present invention.
[0018] Figure 3 This is a flow chart of step S5 of the present invention. DETAILED DESCRIPTION
[0019] The present invention will be further described below with reference to the accompanying drawings.
[0020] like Figure 2 As shown, the method for manufacturing a QFN product based on a water-soluble film process in this embodiment includes the following steps: S1, grinding: grinding the wafer to a set thickness; S2, cutting: a layer of adhesive film is attached to the back of the wafer, and the wafer is cut along the cutting groove to obtain a number of single chips 3; S3, chip loading: attach the chip 3 to the carrier frame 1 by means of conductive adhesive; S4, wire bonding: bonding the lead wire 4 to the chip 3 and the carrier frame 1 to achieve electrical connection; S5, attaching a glass sheet 7 and a hydrosol sheet 8 to the surface of the chip 3; S6, film pasting: pasting a layer of high temperature resistant film on the back of the supporting frame 1; S7, plastic sealing: placing the supporting frame 1 into the mold cavity of the mold, and injecting the plastic sealing colloid 5 at a high temperature of 175°C; S8, baking: maintaining a high temperature of 175° C. for 6 hours until the plastic encapsulation colloid 5 is completely cured; S9, film removal: remove the high temperature resistant film on the back of the supporting frame 1 by heating at 100° C., exposing the guide pins and the base heat sink on the back of the supporting frame 1; S10, cleaning the hydrosol sheet: cleaning with deionized water at 60° C. for 20 minutes to remove the hydrosol sheet 8 on the surface of the glass sheet 7, and then drying at high temperature to expose the glass sheet 7; S11, electroplating: tinning the guide pins on the back of the supporting frame 1 and the heat sinks on the front and back of the supporting frame 1 to facilitate later welding; S12, stamping: laser engraved silk screen corresponding to product information; S13, cutting: dividing the whole frame into single products.
[0021] like Figure 1 , Figure 3 As shown, the specific method of step S5 is as follows: S51, attach the adhesive film 6 to the back of the whole glass sheet 7; S52, attach the water-soluble adhesive sheet 8 to the front of the whole glass sheet 7, heat the vacuum platform to 80±5℃, attach the water-soluble adhesive sheet 8 to the glass sheet 7, the vacuum degree is 10kpa, the roller pressure is 20N; make the surface flat and free of bubbles. S53, separate the glass sheet 7 into the required size by cutting; S54, after cutting, pass 200mj / cm 2 The energy of the UV light is dissolved; S55, the glass sheet 7 is attached to the surface of the chip 3.
[0022] In step S51, the thickness of the adhesive film 6 is 20 um. In specific use, the adhesive film 6 does not need to be baked, which reduces the number of baking times and simplifies the process.
[0023] In step S3, baking is performed after mounting, and the conductive adhesive forms a baking adhesive film 2, fixing the chip 3 on the supporting frame 1. The supporting frame and the chip are bonded by the baking adhesive film 2, which increases the bonding strength between the chip and the frame, and the bonding strength is relatively good.
[0024] In step S5, the thickness of the hydrosol film 8 is 20 um.
[0025] In step S7, the surface of the contact area in the mold cavity with the hydrosol film 8 is mirror-finished, and the roughness Ra is 0.06um. By utilizing the characteristics of the hydrosol film 8, the hydrosol film 8 will deform forcefully when it contacts the surface of the mold cavity, and the glass cut is corrected to achieve flatness.
[0026] In step S7, the center value of the mold cavity thickness is controlled within ±5 um to ensure that the mold surface contacts the hydrosol sheet so that there is no glue overflow during plastic sealing.
[0027] During the plastic sealing in step S7, the water-soluble adhesive sheet 8 is not plastic sealed, so as to facilitate the subsequent cleaning process.
[0028] The present invention utilizes the property of the high molecular material that the water-soluble gel sheet can be completely dissolved in water. The water-soluble gel sheet is firstly attached to the surface of the glass sheet to play a temporary protective role, and then removed with hot water to expose the glass sheet, thereby solving the problem of overflow of plastic sealing material on the glass surface and glass cracking during plastic sealing.
Claims
1. A method for manufacturing QFN products based on a water-soluble film process, characterized in that: The steps include: S1, grinding: grinding the wafer to a set thickness; S2, cutting: a layer of adhesive film is attached to the back of the wafer, and the wafer is cut along the cutting groove to obtain a number of single chips (3); S3, chip mounting: attaching the chip (3) to the supporting frame (1) using conductive adhesive; S4, wire bonding: bonding the lead wire (4) to the chip (3) and the carrier frame (1) to achieve electrical connection; S5, mounting a glass sheet (7) and a hydrosol sheet (8) on the surface of the chip (3); S6, film pasting: pasting a layer of high temperature resistant film on the back of the supporting frame (1); S7, plastic sealing: placing the supporting frame (1) into the mold cavity of the mold, and injecting the plastic sealing colloid (5) at a high temperature of 175°C; S8, baking: maintaining a high temperature of 175°C for 6 hours until the plastic encapsulation colloid (5) is completely cured; S9, film removal: removing the high temperature resistant film on the back of the supporting frame (1) by heating at 100°C, thereby exposing the guide pins (9) and the base heat sink on the back of the supporting frame (1); S10, cleaning the hydrosol sheet: cleaning with deionized water at a temperature of 60° C. for 20 minutes to remove the hydrosol sheet (8) on the surface of the glass sheet (7), and then drying at high temperature to expose the glass sheet (7); The specific method of step S5 is as follows: S51, attaching an adhesive film (6) to the back of the entire glass sheet (7); S52, attaching the hydrosol sheet (8) to the front of the entire glass sheet (7), heating the vacuum platform to 80±5°C, attaching the hydrosol sheet (8) to the glass sheet (7), the vacuum degree is 10 kPa, and the roller pressure is 20 N; S53, separating the glass sheet (7) into required sizes by cutting; S54, after cutting, 200mj / cm 2 The energy of UV solution; S55, attaching the glass sheet (7) to the surface of the chip (3).
2. The method for manufacturing a QFN product based on a water-soluble film process according to claim 1, characterized in that: In the step S51, the thickness of the adhesive film (6) is 20 um.
3. The method for manufacturing a QFN product based on a water-soluble gel sheet process according to claim 1, characterized in that: In the step S5, the thickness of the hydrosol film (8) is 20 um.
4. The method for manufacturing a QFN product based on a water-soluble gel sheet process according to claim 1, characterized in that: In the step S7, the surface of the contact area in the mold cavity with the hydrosol sheet (8) is mirror-finished, and the roughness Ra is 0.06 um.
5. The method for manufacturing a QFN product based on a water-soluble gel sheet process according to claim 1, characterized in that: In the step S7, the center value of the mold cavity thickness is controlled within ±5um.
6. The method for manufacturing a QFN product based on a water-soluble gel sheet process according to claim 1, characterized in that: During the plastic sealing in step S7, the water-soluble gel sheet (8) is not plastic sealed.
7. The method for manufacturing a QFN product based on a water-soluble film process according to claim 1, characterized in that: In the step S3, baking is performed after mounting, and the conductive adhesive forms a baked adhesive film (2), thereby fixing the chip (3) on the supporting frame (1).
8. The method for manufacturing a QFN product based on a water-soluble film process according to claim 1, characterized in that: The following steps are also included: S11, electroplating: tinning the guide pins on the back side of the supporting frame (1) and the heat sinks on the front and back sides of the supporting frame (1); S12, stamping: laser engraved silk screen corresponding to product information; S13, cutting: dividing the whole frame into single products.