Chip sorting method

Abstract

The application provides a chip sorting method, which pre-combines a sensitive adhesive film and a cutting adhesive film into an integrated double-layer film. The pre-cut line formed by pre-cutting the double-layer film plays a stress release role and reduces warping. When sorting the chip, the single chip carries the sensitive adhesive film and is sucked, transferred and adhered to the blue film. If there is silicon slag, micro-crack edge collapse (defect), since the sensitive adhesive film wraps the back of the chip, that is, the silicon slag, micro-crack edge collapse is wrapped by the sensitive adhesive film and when sorting the chip, the chip carries the sensitive adhesive film and is sucked, transferred and adhered to the blue film; in this way, the silicon slag, micro-crack edge collapse is wrapped by the sensitive adhesive film and will not fall off, with zero silicon slag falling risk. The silicon slag pollution problem of the chip in the sorting process is solved, and after the sensitive adhesive film is handled by losing adhesion, lossless degumming is realized, the chip is more easily sucked, and the success rate of sucking the chip is improved.

Description

Technical Field

[0001] This invention belongs to the field of integrated circuit manufacturing technology, and specifically relates to a chip sorting method. Background Technology

[0002] Chip sorting is a crucial step in semiconductor manufacturing, involving the automatic classification and grading of chips based on parameters such as electrical performance, optical characteristics, or physical dimensions. Simply put, it involves categorizing manufactured chips according to their quality and performance level, ensuring that only qualified chips proceed to the next stage.

[0003] During wafer dicing, the external force exerted by the dicing cut may generate silicon dross on the back of the chip. During chip sorting, the pick-and-place nozzle detaches the chip from the thin film, resulting in silicon dross shedding, microcracks, and chipping, creating new debris. Silicon dross falling during sorting damages the chip surface. Furthermore, the silicon dross generated by the chip may adhere to the pick-and-place nozzle, causing surface damage to chips picked up by subsequent nozzles. Summary of the Invention

[0004] The purpose of this invention is to provide a chip sorting method in which silicon slag and microcracks are encapsulated by a sensitive adhesive film, preventing them from falling off and eliminating the risk of silicon slag falling off. This solves the problem of silicon slag contamination during chip sorting and, by utilizing the de-adhesion properties of the sensitive adhesive film, achieves non-destructive debonding, making chip pick-up easier and improving the success rate of chip pick-up.

[0005] This invention provides a chip sorting method, comprising:

[0006] S1. Pre-composite the sensitive adhesive film and the cutting adhesive film into an integrated double-layer film;

[0007] S2. The double-layer film is pre-cut to a certain depth, while keeping the surface of the cut film away from the sensitive film intact, and the double-layer film as a whole remains connected.

[0008] S3. The double-layer film is attached to the back of the thinned wafer, and the sensitive adhesive film is attached to the back of the wafer;

[0009] S4. Die-cut the wafer, cutting through the wafer and the sensitive adhesive film and stopping at the bottom layer of the dicing adhesive film;

[0010] S5. Sorting chip: Each chip, along with the sensitive adhesive film, is picked up, transferred, and adhered to the blue film.

[0011] S6. Utilizing the temperature-sensitive properties of the sensitive adhesive film, the sensitive adhesive film on the back of the chip is subjected to heat-induced de-adhesion or low-temperature de-adhesion treatment before bonding, so as to facilitate the pick-up of the chip.

[0012] Furthermore, in step S1, the sensitive adhesive film and the cutting adhesive film are laminated together at the front end of the incoming material using a roller press to form an integral double-layer film, with the adhesive surface of the cutting adhesive film attached to the back of the sensitive adhesive film.

[0013] Furthermore, in the roller lamination process, the lamination pressure is 0.3 MPa ~ 0.8 MPa, the lamination speed is 0.5 m / min ~ 3 m / min, and the heat-sensitive adhesive film lamination temperature is 40°C ~ 80°C.

[0014] Furthermore, the thickness range of the sensitive adhesive film is 65 μm to 130 μm; the sensitive adhesive film comprises a laminated base film and an adhesive layer, the thickness range of the base film is 50 μm to 100 μm; and the thickness range of the adhesive layer is 15 μm to 30 μm.

[0015] Furthermore, the adhesive layer is made of heat-sensitive or cold-sensitive acrylic adhesive; the base film is made of at least one of polyvinyl chloride, polyolefin, and polyester.

[0016] Furthermore, in step S2, the double-layer film is pre-cut with a laser with an accuracy of ±0.05mm, cutting through 60%-80% of the total thickness of the double-layer film and cutting through to 20%-25% of the thickness of the cut film.

[0017] Furthermore, in step S4, the wafer is diced using laser and / or blade cutting.

[0018] Furthermore, in step S6, the sensitive adhesive film includes a heat-sensitive adhesive film or a cold-sensitive adhesive film.

[0019] Furthermore, the temperature range for the heat-sensitive adhesive film to undergo de-adhesion treatment is 80~120°C, and the treatment time is 30s~60s;

[0020] The temperature range for the low-temperature de-adhesion treatment of the cold-sensitive adhesive film is -40°C to -20°C, and the treatment time is 30s to 120s.

[0021] Furthermore, after the heat-sensitive adhesive film undergoes heat-induced de-adhesion treatment, the residual adhesive area ratio is < 0.3%; after the cold-sensitive adhesive film undergoes low-temperature de-adhesion treatment, the residual adhesive rate is < 0.5%.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention provides a chip sorting method, comprising: S1, pre-compositing a sensitive adhesive film and a dicing adhesive film into an integral double-layer film; S2, pre-cutting the double-layer film to a certain depth, leaving the surface of the dicing adhesive film away from the sensitive adhesive film intact, while the double-layer film remains connected as a whole; S3, attaching the double-layer film to the back of a thinned wafer, and attaching the sensitive adhesive film to the back of the wafer; S4, dicing the wafer, cutting through the wafer and the sensitive adhesive film, stopping at the bottom layer of the dicing adhesive film; S5, sorting the chips, with each chip carrying the sensitive adhesive film being picked up, transferred, and adhered to a blue film; S6, utilizing the temperature-sensitive characteristics of the sensitive adhesive film, performing a heat-induced de-adhesion or low-temperature de-adhesion treatment on the back of the chip before bonding to facilitate chip pickup.

[0024] This invention provides a chip sorting method that pre-composite a sensitive adhesive film and a cutting adhesive film into an integrated double-layer film. Pre-cutting the double-layer film creates pre-cut lines that release stress and reduce warping. During chip sorting, each chip, carrying the sensitive adhesive film, is picked up, transferred, and adhered to the blue film. If silicon slag or microcracks (chipping) are present, the sensitive adhesive film covers the back of the chip, meaning all silicon slag and microcracks are encapsulated by the sensitive adhesive film. Furthermore, during chip sorting, the chip, carrying the sensitive adhesive film, is picked up, transferred, and adhered to the blue film. In this way, silicon slag and microcracks are contained within the sensitive adhesive film and will not fall off, eliminating the risk of silicon slag falling off. This solves the problem of silicon slag contamination during chip sorting and utilizes the de-adhesion properties of the sensitive adhesive film for non-destructive debonding, making chip picking easier and improving the chip picking success rate. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a chip sorting method according to an embodiment of the present invention, in which a sensitive adhesive film and a cutting adhesive film are combined into an integral double-layer film.

[0026] Figure 2 This is a schematic diagram of the pre-cutting of a double-layer film in a chip sorting method according to an embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram illustrating the movement of the chip along with the sensitive adhesive film during the sorting step in a chip sorting method according to an embodiment of the present invention.

[0028] Figure 4 This is a schematic diagram illustrating a chip sorting method according to an embodiment of the present invention, in which chips with defects are wrapped in a sensitive adhesive film and are picked up and moved together with the sensitive adhesive film during chip sorting. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0030] For ease of description, some embodiments of this application may use spatially relative terms such as “above,” “below,” “top,” and “under” to describe the relationship between one element or component and another (or more) elements or components as shown in the accompanying drawings. It should be understood that, in addition to the orientations described in the drawings, spatially relative terms are also intended to include different orientations of the device during use or operation. For example, if the device in the drawings is flipped, it is described as an element or component “below” or “under” other elements or components, and will subsequently be positioned “above” or “on” other elements or components. The terms “first,” “second,” etc., used below are used to distinguish between similar elements and are not necessarily used to describe a particular order or temporal sequence. It should be understood that these terms, as used, may be replaced where appropriate.

[0031] This invention provides a chip sorting method, including:

[0032] S1. Pre-composite the sensitive adhesive film and the cutting adhesive film into an integrated double-layer film;

[0033] S2. Pre-cut the double-layer film to a certain depth, keeping the surface of the cut film away from the sensitive film intact, while the double-layer film remains connected as a whole.

[0034] S3. A double-layer film is pasted on the back of the thinned wafer, and a sensitive adhesive film is pasted on the back of the wafer;

[0035] S4. Divide the wafer, cutting through the wafer and the sensitive adhesive film, stopping at the bottom layer of the dicing adhesive film;

[0036] S5, sorting chip: a single chip carrying a sensitive adhesive film is picked up, transferred and adhered to the blue film.

[0037] S6. Utilizing the temperature-sensitive properties of the sensitive adhesive film, the sensitive adhesive film on the back of the chip is subjected to heat-induced de-adhesion or low-temperature de-adhesion treatment before bonding to facilitate chip pick-up.

[0038] This invention provides a method for protecting the back side of chips and improving pick-up success rate during chip sorting. It reduces yield loss caused by silicon dross falling and damaging the chip surface. It effectively protects the back side of chips, prevents silicon dross from falling, reduces yield loss, and improves customer satisfaction. It is compatible with customer process differences, further enhancing customer satisfaction.

[0039] The steps of the chip sorting method according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0040] Step S1, as follows Figure 1 As shown, a sensitive adhesive film and a cutting adhesive film are pre-laminated into an integral double-layer film. Exemplarily, the sensitive adhesive film and the cutting adhesive film can be pre-laminated into an integral double-layer film at the front end of the incoming material using roll lamination. The adhesive side of the cutting adhesive film is bonded to the back side of the sensitive adhesive film. In the roll lamination process, the bonding pressure is 0.3 MPa ~ 0.8 MPa, the bonding speed is 0.5 m / min ~ 3 m / min, and the bonding temperature of the heat-sensitive adhesive film is 40°C ~ 80°C. The cold-sensitive adhesive film can be bonded at room temperature. This invention differs from traditional single-layer cutting films by introducing a combination of a sensitive adhesive film and a cutting adhesive film. The thickness range of the sensitive adhesive film is 65 μm ~ 130 μm; the sensitive adhesive film includes a laminated base film and an adhesive layer, with the base film thickness ranging from 50 μm to 100 μm and the adhesive layer thickness ranging from 15 μm to 30 μm. The adhesive layer material can be a heat-sensitive or cold-sensitive acrylic adhesive. The base film material can be at least one of polyvinyl chloride, polyolefin and polyester.

[0041] Step S2, as follows Figure 2 As shown, the bilayer film is pre-cut, with the cut depth forming a pre-cut line. The surface of the cut film away from the sensitive adhesive film remains intact, and the bilayer film as a whole remains connected. The pre-cut line left after the bilayer film pre-cutting serves to release stress. During subsequent wafer thinning and polishing, the bilayer film naturally releases stress along the pre-cut line, reducing warpage. The bilayer film can be pre-cut using a laser (e.g., a UV laser) with an accuracy of ±0.05mm, cutting through 60%-80% of the total thickness of the bilayer film and cutting through to 20%-25% of the adhesive film thickness.

[0042] Step S3: Apply a double-layer film to the back of the thinned wafer, and then apply a sensitive adhesive film to the back of the wafer. After applying the double-layer film to the back of the wafer, remove excess waste film along the pre-cut line and attach a metal frame. On the back of the thinned wafer, apply the double-layer film and attach it to the metal frame, forming a three-layer structure of "wafer-sensitive adhesive film-cutting adhesive film". The wafer thinning process specifically includes: applying back-side grinding tape to the front of the wafer, performing back-side grinding to thin to the target thickness, and removing the stress layer. A wafer laminator is used to apply back-side grinding tape to the front of the wafer. Back-side grinding tape is a key consumable in semiconductor manufacturing for wafer thinning processes; its main function is to protect the completed circuit structure on the front of the wafer from damage during back-side grinding.

[0043] Step S4: Divide the wafer, cutting through the wafer and the sensitive adhesive film, stopping at the bottom dicing film. Dividing can be done using laser and / or blade cutting. The wafer is then transferred to the dicing station for dicing, with precise control of the cutting depth to completely cut through the wafer body and the sensitive adhesive film in the middle, stopping at the bottom dicing film.

[0044] Step S5, as follows Figure 3 and Figure 4 As shown, in the chip sorting process, each chip, along with a sensitive adhesive film, is picked up, transferred, and adhered to a blue film. Unlike traditional bare chip sorting, this invention involves transferring the chip along with the sensitive adhesive film. If silicon slag or microcracks (chipping) exist in previous processes (e.g., dicing), in this invention, because the sensitive adhesive film covers the back of the chip, all silicon slag and microcracks are encapsulated by the sensitive adhesive film. Furthermore, during chip sorting, the chip is picked up along with the sensitive adhesive film, transferred, and adhered to the blue film. In this way, silicon slag and microcracks are encapsulated by the sensitive adhesive film and will not fall off during the picking and moving process, eliminating the risk of silicon slag falling off. This reduces the risk of chip surface damage during chip sorting and reduces yield loss.

[0045] Step S6: Utilizing the temperature-sensitive properties of the adhesive film, the adhesive film on the back of the chip is subjected to heat-induced de-adhesion or low-temperature de-adhesion treatment before bonding to facilitate chip removal. Specifically, by utilizing the properties of heat-sensitive adhesive film (heat-induced de-adhesion) or cold-sensitive adhesive film (low-temperature de-adhesion), residual adhesive on the back of the chip can be easily de-adheded before bonding to facilitate chip removal. Unlike traditional mechanical peeling, this invention utilizes heat-sensitive / cold-sensitive de-adhesion properties to achieve non-destructive debonding. The adhesive film includes heat-sensitive adhesive film and cold-sensitive adhesive film; the heat-induced de-adhesion treatment temperature range for heat-sensitive adhesive film is 80~120°C, and the treatment time is 30s~60s. The low-temperature de-adhesion treatment temperature range for cold-sensitive adhesive film is -40°C~-20°C, and the treatment time is 30s~120s. Residual adhesive rate after de-adhesion: After the heat-sensitive adhesive film is heated to 80°C~120°C, the residual adhesive area rate is < 0.3%. After cold-sensitive adhesive film is treated at low temperatures of -40°C to -20°C, the residual adhesive rate is < 0.5%.

[0046] In summary, this invention provides a chip sorting method that pre-composite a sensitive adhesive film and a cutting adhesive film into an integrated double-layer film. The pre-cut lines formed by pre-cutting the double-layer film serve to release stress and reduce warping. During chip sorting, each chip, carrying the sensitive adhesive film, is picked up, transferred, and adhered to the blue film. If silicon slag or microcracks (chipping) are present, because the sensitive adhesive film covers the back of the chip, that is, the silicon slag and microcracks are completely encapsulated by the sensitive adhesive film, and during chip sorting, the chip, carrying the sensitive adhesive film, is picked up, transferred, and adhered to the blue film; thus, the silicon slag and microcracks are encapsulated by the sensitive adhesive film and will not fall off, eliminating the risk of silicon slag falling off. This solves the problem of silicon slag contamination during chip sorting and, by utilizing the de-adhesion properties of the sensitive adhesive film, achieves non-destructive debonding, making chip picking easier and improving the chip picking success rate.

[0047] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The methods disclosed in the embodiments are described simply because they correspond to the devices disclosed in the embodiments; relevant details can be found in the method section.

[0048] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A chip sorting method, characterized in that, include: S1. Pre-composite the sensitive adhesive film and the cutting adhesive film into an integrated double-layer film; S2. The double-layer film is pre-cut to a certain depth, while keeping the surface of the cut film away from the sensitive film intact, and the double-layer film as a whole remains connected. S3. The double-layer film is attached to the back of the thinned wafer, and the sensitive adhesive film is attached to the back of the wafer; S4. Die-cut the wafer, cutting through the wafer and the sensitive adhesive film and stopping at the bottom layer of the dicing adhesive film; S5. Sorting chip: Each chip, along with the sensitive adhesive film, is picked up, transferred, and adhered to the blue film. S6. Utilizing the temperature-sensitive properties of the sensitive adhesive film, the sensitive adhesive film on the back of the chip is subjected to heat-induced de-adhesion or low-temperature de-adhesion treatment before bonding, so as to facilitate the pick-up of the chip.

2. The chip sorting method as described in claim 1, characterized in that, In step S1, the sensitive adhesive film and the cutting adhesive film are laminated together at the front end of the incoming material using a roller to form an integral double-layer film, with the adhesive surface of the cutting adhesive film attached to the back of the sensitive adhesive film.

3. The chip sorting method as described in claim 2, characterized in that, In the roller lamination process, the lamination pressure is 0.3 MPa ~ 0.8 MPa, and the lamination speed is 0.5 m / min ~ 3 m / min. Heat-sensitive adhesive film lamination temperature: 40°C ~ 80°C.

4. The chip sorting method as described in claim 1, characterized in that, The thickness range of the sensitive adhesive film is 65 μm to 130 μm; the sensitive adhesive film comprises a laminated base film and an adhesive layer, the thickness range of the base film is 50 μm to 100 μm; the thickness range of the adhesive layer is 15 μm to 30 μm.

5. The chip sorting method as described in claim 4, characterized in that, The adhesive layer is made of heat-sensitive or cold-sensitive acrylic adhesive; the base film is made of at least one of polyvinyl chloride, polyolefin and polyester.

6. The chip sorting method as described in claim 1, characterized in that, In step S2, the double-layer film is pre-cut with a laser with an accuracy of ±0.05mm, cutting through 60%-80% of the total thickness of the double-layer film and cutting through to 20%-25% of the thickness of the cut film.

7. The chip sorting method as described in claim 1, characterized in that, In step S4, the wafer is diced using laser and / or blade cutting.

8. The chip sorting method as described in claim 1, characterized in that, In step S6, the sensitive adhesive film includes a heat-sensitive adhesive film or a cold-sensitive adhesive film.

9. The chip sorting method as described in claim 8, characterized in that, The temperature range for heat-induced de-adhesion treatment of the heat-sensitive adhesive film is 80~120°C, and the treatment time is 30s~60s. The temperature range for the low-temperature de-adhesion treatment of the cold-sensitive adhesive film is -40°C to -20°C, and the treatment time is 30s to 120s.

10. The chip sorting method as described in claim 9, characterized in that, After the heat-sensitive adhesive film undergoes heat-induced de-adhesion treatment, the residual adhesive area ratio is < 0.3%; after the cold-sensitive adhesive film undergoes low-temperature de-adhesion treatment, the residual adhesive rate is < 0.5%.

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