TW578267B - Method of preventing particles from falling on wafer during wafer dicing - Google Patents

Abstract

A method of preventing particles from falling on wafer during wafer dicing is provided, in which the wafer contains CMOS image sensors formed thereon. The method comprises following steps: coating a non-water soluble material layer on the top side of the wafer, in which wafer contains CMOS image sensors formed thereon; adhering a tape onto the back side of the wafer; dicing the wafer with the tape adhered thereon; and removing the non-water soluble material layer.

Description

578267 V. Description of the invention (1) Field of the invention: The present invention relates to a method for preventing particles from falling onto a wafer during wafer dicing, and in particular to a method for preventing particles from falling onto a complementary metal oxide semiconductor during wafer dicing. metal oxide semiconductor (CMOS) image sensor (CMOS image sensor; CIS). BACKGROUND OF THE INVENTION: Image sensors are currently quite common optical components, such as scanners that have been popular in the market for a long time, and digital cameras that are currently popular. They all have built-in image sensors. Image sensors mainly include charge coupled dev ice (CCD) image sensors and CMOS image sensors. Among them, CMOS image sensors have operating voltages compared to CCD image sensors. Low, low power consumption, compatible with logic circuits, random access, and low cost, so it is widely used in the semiconductor industry. Die cutting is a semiconductor packaging process (for example, plastic packaging process requires sequential die cutting, die mounting (wire bond), mold forming, baking hardening, lead money tin, An important step in the steps of lead cutting and forming), in which the die 7 cutting process is to cause the goodness of the CMOS image sensor fabricated on the wafer = drop =

1/1/5 Invention explains the main reason of (2), in order to cut the traditional grains more; φ * bang to explain this reason, please refer to Figure 1, which is a 々 / 2: 夂 flow chart. As shown in Figure 1, the first coupon ^ (blue tape) sticks to a winning tape (such as the conventional blue tape-side) (steps; oV knife damages the back of the L wafer (that is, there is no component-shaped wafer on the When cutting, no wafers will be produced: '^ After the back side is adhered with tape' wafer (step 12). A wafer. Then, this adhesive tape is cut.

Water is always used to advance the wafers; while the wafers are cut at the same time, it is usually necessary to continue the die bonding process. In the process of the traditional die cutting method, when the wafers are in

1 γ said that particles will be generated where the circle is cut, and the particles are easy to rise. If the wafer has a CMOS image sensor formed at its mouth, the particles are easily raised and Dropped onto the active area of the CMOS image sensor \ Because the CMOS image sensor has high sensitivity to particles, the yield of the CMOS shirt image sensor will be greatly reduced (all CMOS fabricated on the wafer Image sensors, about 15% to 20% of the "⑽ image sensors will be damaged because of the particles attached to them.) So how to avoid particles generated during wafer dicing because they fall on the wafer surface It is very important that the function of the CMOS image sensor fails due to the CMOs image sensor. The purpose and summary of the invention:

(Page 3 3 / 5Zt) 7

Not inventing the ~ q method on providing a 〇s image sensor. 〇 Ways to prevent particles from falling during wafer dicing to increase the good image sensing of 〇s image sensor: 2: 1: avoid crystal Particles dropped to CM0S during circular cutting ^ Village layer positive = less coating non-injury a curve on which the front side of this wafer has CMOS.! The image sensor is formed on 1. The spot base sheds L ^ ^ Ingenious cutting I I 1 λ ^, adhesive tape on the back of this wafer; seven

-The wafer with >tape; removes the water-insoluble material layer. The material of the water-insoluble material layer can be a material that is soluble in organic solvents (for example, a conventional positive photoresist or a negative photoresist without a photosensitizer is used as the material of the water-insoluble material layer), For example, one of the following materials can be used as the material of the water-insoluble material layer: P〇ly ethylene, Poly Methyl Methacry1 ate (PMMA) > Poly Glycidol Methacrylate (PGMA) ^ Propylene Glycol Monoethyl

Ether Acetate 'Ethylene Glycol Monoethyl Ether

Acetate, Cyclized 1,4-cis polyisoprene, Novolak resin, Metacrylate resin, Cresol formaldehyde resin, Ethyl lactate, Ethyl 3-ethoxypropionate. In addition, if the material of the above water-insoluble material layer is positive photoresist, remove the # water-soluble material layer The method includes the following steps:

Page 7 578267 V. Description of the invention (4) Exposure; develop the water-insoluble material layer. If the material of the water-insoluble material layer is a negative photoresist that does not contain a photosensitizer, the method of removing the water-insoluble material layer is to develop the water-insoluble material layer. The developer used for developing the water-insoluble material layer includes one of the following: an aqueous solution of NaOH, an aqueous solution of KOH, an aqueous solution of tetramethylammonium hydroxide (TMAH, Tetra Methyl Amonium Hydroxide), and isopropyl alcohol (IPA, Isopropanol) Xylene, Acetone, Phenol, monomethyl ether propylene glycol acetic acid (Própyiene GiyCoi Monomethyl Ethyl Acetate), Propylene Glycol Monomethyl Ether, Ethylene Glycol. 4% 〜1 〇%。 The weight percentage concentration of the solute in the developer is 0.4% to 10%. Detailed description of the invention: According to an embodiment of the present invention, the method for preventing particles from falling on the C MOS image sensor during wafer cutting according to the present invention is described in detail as follows: Please refer to FIG. 2 as a basis According to an embodiment of the present invention, a flowchart of a method for preventing particles from falling onto a CMOS image sensor during wafer dicing is provided. As shown in FIG. 2, firstly, a water-insoluble material layer is coated on the front side of the wafer (that is, the side formed by the CMOS image sensor) (step 20). Then ‘stick a tape (such as the conventional biue tape)

578267

On the back surface of the wafer to be cut with the CMOS image sensor formed thereon (ie, the side without the CMOS image sensor formed) (step 22). Next, the wafer with the adhesive tape is cut (step 24). Next, the water-insoluble material layer is removed (step 26). The grains obtained after removing the water-insoluble material layer will then continue with the grain bonding (mount) procedure. Among them, after the above wafer is adhered with adhesive tape, the wafer will not generate fragments during dicing. In addition, at the same time as wafer dicing, it is usually necessary to spray and clean the wafer with water from time to time. Since the CM0S image sensor is covered with a layer of water-insoluble material, CM0s Because the image sensor is protected by a layer of water-insoluble material, particles generated during cutting can be prevented from falling onto the active area of the CMOS image sensor.

Moreover, the material of the water-insoluble material layer may be a material that is soluble in an organic solution. For example, a conventional positive photoresist or a negative photoresist without a photosensitizer is used as the material of the water-insoluble material layer. And because the positive photoresist has the property that it can be dissolved by the developer after exposure, if the material of the water-insoluble material layer is a conventional positive photoresist, it must go through two steps of exposure and development in order to convert the water-insoluble material. The photoresist-free negative photoresist can be dissolved by the developer with or without exposure, so if the material of the water-insoluble material layer is a conventional photoresist-free negative photoresist, it only needs to pass through. One step of development can remove the water-insoluble material layer. In other words, if a known positive photoresist is used as the material of the water-insoluble material layer, the above-mentioned step of removing the water-insoluble material layer (step 26) actually needs to include two steps

Page 9 578267 V. Description of the invention (6) = From) Expose this water-insoluble material layer. (2) This is not water; However, if a conventional material without a photosensitizer is used as the material of the negative light field water-insoluble material layer, the above-mentioned step (step 26) of removing the water-insoluble material only needs to include one step: the water-insoluble material The layers are developed. The material of the above-mentioned water-insoluble material layer includes polyethylene (polyyl alcohol), polymethyl ethyl acrylate (PMMA), and polyglycidol methacrylate (PGMA). ), Propylene Glycol Monoethyl Ether Acetate, Ethylene Glycol Monoethyl Ether Acetate, Cyclized 1,4-cis polyisoprene, Novolak resin,

Metacrylate resin, Cresol formaldehyde resin, Ethyl lactate,

Ethyl 3-ethoxypropionate ° and the developer used to remove the water-insoluble material layer can be: NaOH aqueous solution, K0H aqueous solution, Tetra Methyl Amonium Hydroxide (TMAH) aqueous solution, IPA, Isopropanol , Xylene 'Acetone, Phenol, Propylene Glycol Monomethyl Ethyl Acetate, Propylene Glycol Monomethyl Ether, Ethylene Glycol), where the weight percent of solute in the developer

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The concentration is about 0.4% ~ 10%, and the preferred weight percentage roll is about i% 2%. ,,,,,,, and 0 are the main reduction of the particles falling into the former (detector, on-wafer image sensing process on the wafer. Therefore, using the method of the present invention to perform die cutting will not There will be a situation where it falls on the wafer, so for a wafer with a CM0s image sense just on it, particles will not fall on the CM0s image sense motion area. The yield of the CMOS image sensor is much larger than the traditional dicing process, which will cause all CMOs images produced on the wafer ^ About 15 ° / 20% of the CMOS image sensor will be damaged due to particle adhesion). Of course, the method of the present invention is not limited to the cutting process of all CMOS image sensors produced, as long as the components are made, those with high sensitivity to particulate contamination (such as cc / detector) are all The method of the present invention can be used for dicing. Generally speaking, the removal timing of the above water-insoluble material layer is after the dicing process of the wafer is completed, and the die m0unt is performed. Ί ί = Before, the relevant removal process 4 can be performed in order to remove the water-insoluble material t. However, the above protective layer can also be used to cut the wafer 4 and complete the die bonding process. To remove. It is worth noting that the sequence layer of the above water-insoluble material is removed at least two times before the wire bonding process. Although the present invention is explained as above with a preferred example,

Ran Fan

578267 V. Description of the invention (8) Equivalent changes or modifications made under the spirit disclosed by the invention shall be regarded as the protection scope of the invention. The scope of patent protection of the present invention depends on the scope of patent application and its equivalent fields. liiin Page 12 578267 Brief description of the diagram ^ A is a flowchart of a conventional die cutting method, and Figure 2 is an embodiment of the present invention to prevent particles from falling to the CMOS image sensor during wafer cutting Flowchart of the method on page 1ϋΒΙΙ page 13

Claims (1)

578267 ▲ 1. A method to prevent particles from falling onto the wafer during wafer dicing. 6. Scope of patent application This method includes at least the following steps: positive =: layer on the front side of the wafer, "the front side of the wafer has A semiconductor element is formed thereon; an adhesive tape is adhered to the back surface of the wafer; and the wafer with the adhesive tape is cut, wherein the water-insoluble material layer can prevent cutting slightly from the front side during the cutting process: 2. The method according to item 1 of the scope of patent application, wherein the above-mentioned semiconductor element includes a CMOS image sensor. 3. The method according to item 1 of the scope of patent application, wherein the above-mentioned semiconductor element includes a CCD image sensor. + 4 · The method according to item 1 of the patent application, wherein the material of the above water-insoluble material layer may be a material that is soluble in an organic solution. 5. The method according to item 1 of the patent application, wherein the above water-insoluble material The material of the material layer includes a positive photoresist or a negative photoresist that does not contain a photosensitizer. 6. The method according to item 1 of the scope of patent application, wherein the material package of the above water-insoluble material layer One of the following: polyethylene (P〇ly ethylene), polymethyl methacrylate particles (p〇iy Methyl 578267 6. Scope of patent application: Methacrylate (PMMA), Poly Glycidol Methacrylate (PGMA), Propylene Glycol Monoethyl Ether Acetate, Ethylene Glycol Monoethyl Ether Acetate , Cyclized 1,4-cis polyisoprene, Novolak resin, Metacrylate resin, Cresol formaldehyde resin, Ethyl lactate ), Ethyl 3-ethoxypropionate ° 7. The method according to item 1 of the patent application scope, wherein the above method further includes a step of removing the water-insoluble material layer after cutting the wafer to which the tape is adhered. 8. The method according to item 7 of the scope of patent application, wherein if the material of the above water-insoluble material layer is a positive photoresist, the method of removing the water-insoluble material layer includes the following steps: exposing the non-water> valley material layer; This water-insoluble material layer is developed. 9. The method according to item 8 of the patent application, wherein the developer used for developing the insoluble material layer includes one of the following: NaOH aqueous solution, KOH aqueous solution, tetramethylammonium hydroxide (butyl mah, Methyl Amonium Hydroxide) aqueous solution, isopropanol, 578267 6. Scope of Patent Application (IPA, Isopropanol), Xylene, Acetone, Phenol, ProPylene Glycol Monomethyl Ethyl Acetate, Monomethyl Ethyl Acetate (Propylene Glycol Monomethyl Ether), ethylene glycol (Ethy 1ene G 1 yco1). 10. The method according to item 9 of the scope of patent application, wherein the weight percentage concentration of the solute in the developer is 0.4% to 10%. 11. The method according to item 7 of the scope of patent application, wherein if the material of the water-insoluble material layer is a negative photoresist without a photosensitizer, the method of removing the water-insoluble material layer is to perform the water-insoluble material layer development. 12. The method according to item 11 of the application, wherein the developer used to develop the water-insoluble material layer includes one of the following: NaOH aqueous solution, KOH aqueous solution, tetramethylammonium hydroxide (TMAH, Tetra Methyl Amonium) Hydroxide) aqueous solution, IPA, Isopropanol, xyiene, Acetone, Phenol, proypyene Glycol Monomethyl Ethyl Acetate, monomethyl Ethylene propylene glycol (Propylene Glycol Monomethyl Ether), ethylene glycol (Ethy1ene Glycol). 13. The method according to item 12 of the patent application range, wherein the developer Page 16 578267 The weight percent concentration of the solute is from 0.4% to 丨 0%. 14. A method for preventing particles from falling to a when the wafer is cut, wherein the wafer has a CMOS image inspection number, and is fixed on the day, at least including the following steps: I is formed on it, and the method is applied to A non-water-soluble material layer is formed on the front side of the wafer, and the front side of the basin has the CMOS image sensor formed thereon; eight r ^ Japanese yen is stuck with a tape on the back side of the wafer; the tape is cut and stuck with the tape The wafer; removing the water-insoluble material layer. 15. The method according to item 14 of the scope of patent application, wherein the material of the non-water-soluble material layer may be a material soluble in an organic solution. 16. The method according to item 14 of the patent application range, wherein the material of the non-water-soluble material layer includes a positive photoresist or a negative photoresist without a photosensitizer. 17. The method according to item 14 of the scope of patent application, wherein the material of the above-mentioned water-insoluble material layer includes one of the following: Poly (ethylene) (Poly 'ethylene), polymethyl methacrylate particles (p〇iy Methyl Methacrylate (PMMA), Poly Glycidol Methacrylate (PGMA), Propylene Glycol Monoethyl Ether Acetate, Ethylene Glycol Monoethyl Ether Acetate, Page 17 578267 VI. Scope of patent application Cyclized 1,4-cis polyisoprene, Novolak resin, Metacry late resi η, kerosene phenol formaldehyde (Cre sol formaldehyde resin), Ethyl lactate, Ethyl 3-ethoxypropionate o 18. If the method of the scope of patent application No. 14 is applied, if the material of the above-mentioned water-soluble material layer is positive photoresist, the water-insoluble material is removed. The material layer method includes the following steps: Expose the water-insoluble material layer; develop the water-insoluble material layer. 19. The method according to item 18 of the scope of patent application, wherein the developer used for developing the water-insoluble material layer includes one of the following: NaOH aqueous solution, KOH aqueous solution, tetramethylammonium hydroxide (TMAH, Tetra Methyl Amonium Hydroxide) solution, IPA, Isopropanol, xyiene, Acetone, Phenol, propyiene Glycol Monomethyl Ethyl Acetate, Propylene Glycol Monomethyl Ether, and ethylene glycol (Ethy1ene Glycol). 2 · The method according to item 19 of the scope of patent application, wherein the weight percentage concentration of the solute in the developer is 0.4% to 10%. Page 18 578267 Sixth, the scope of the application for patent 21. The material of soluble material layer The material of soluble material, such as material No. 14 of the scope of application for patent, is the method without the photosensitizer layer, which is the non-aqueous method. This water-insoluble material layer is removed and developed. 2 2 · As stated in the method of item 21 of the patent scope, wherein the developer used for the development of the water-insoluble material layer described above includes one of the following: NaOH aqueous solution, KOH aqueous solution, trioxane (TMAH, Tetra Methyl Amonium Hydroxide) solution, IPA, Isopropanol, xylene, Acetone, Phenol, proypyene Glycol Monomethyl Ethyl Acetate ), Propylene Glycol Monomethyl Ether, Ethylene Glycol. 2 3. The method according to item 22 of the patent application range, wherein the weight percentage concentration of the solute in the developer is 0.4% to 10%. 2 4. A protective layer is applied on the upper surface of the wafer to prevent particles from falling onto the semiconductor elements on the surface of the wafer during dicing. The protective layer is composed of a water-insoluble material. 25. The protective layer according to item 24 of the scope of patent application, wherein the non-water-soluble material may be a material soluble in organic solution. Page 19 578267 VI. Application scope of patent 26. If the protection layer of the scope of application for patent No. 24, the above non-water-soluble material contains positive photoresist or negative photoresist without photosensitizer. 27. The protective layer according to item 24 of the application for a patent, wherein the above water-insoluble material includes one of the following: Polyethylene, Poly Methyl Methacrylate (PMMA), Polyfluorene-based Polyglycidol Methacrylate (PGMA), Propylene Glycol Monoethyl Ether Acetate, Ethylene Glycol Monoethyl Ether Acetate, cyclized cis-polyisopropyl diisocyanate 1, 4 ( Cyclized l, 4-cis polyisoprene), Novolak resin, Metacrylate resin, Cresol formaldehyde resin, Ethyl lactate, Ethyl 3-ethoxypropionate ° Page 20