TW556280B - Method of preventing silicon powder residue after wafer dicing - Google Patents

Abstract

A kind of method of preventing silicon powder residue after wafer dicing is disclosed. A coating layer is applied on the surface of the wafer before wafer dicing, which is followed by sending the wafer with the coating layer thereon into wafer dicing machine to be diced. After the wafer is diced, the coating layer on the wafer is removed. Through the coating layer covered on the wafer surface, the silicon powder produced during wafer dicing remained on the chip surface traditionally can be prevented as it affects the subsequent manufacturing processes and product quality. Through the process removing the coating layer on the wafer surface, the silicon powder remained on the surface of the coating layer can be cleared away at the same time.

Description

556280 Revised month 5. Description of the invention (1) [Field of invention] π: The month is related to a method for preventing the residue of silicon powder after wafer dicing, especially before coating on the surface of the wafer- Layer draped. , :: Two to; The method of silicon powder remaining on the surface of the crystal grain after cutting. s Xi he f and a half? In the system process, ′ will be produced on the wafer at the same time: ~ 10 mm rectangular die (Die), in each: 2 =

After Saw), the crystal grains will be chamfered; di-ckage can only be applied. Front \ Electricity n / Separately assembled (Pa processed Jing®, according to ;;: =: =; This wafer is cut in the previous process, and the wafer is divided into reet) = Wafer cutting, such as The first drawing: J number-grain. For the intermediary, Bund A spleen day Π1, Beibei 1 set the steel frame 3 in the office ..., and then place the back of Yen 1 and the steel frame 3 _ Adhesive tape 2 (Wafer Tape) 2 Paste-: = Glue particles === After cutting, borrow "p * SL, ρπη *, ^. ', Λ orderly arrangement and adhesion on the surface of the adhesive tape 2 and the adhesive tape 2 can be avoided due to the support of the frame To prevent the grains from colliding with each other, and J ^ uang ^ and subsequent related processes. 彳 The tape is also easy to transport in the wafer cutting stage mentioned above, because the wafer's I crystal 'regardless of the material used to cut the crystal: Group: ：： The production of shavings and silicon powder, so to ensure the clean quality & Avoid page 4 556280

The produced stone powder is added with carbon dioxide (◦ I) in the water to dissipate the static electricity generated during the cutting process. However, an excessive amount of carbon dioxide will result in the production of excessive carbon morgue rat root ions (HC 〇3). 'As a result, the cutting water with weak acid will invade the surface of the crystal grains, causing the phenomenon of grain corrosion; in addition, if the cleaning angle is not proper or the water pressure is insufficient during the cleaning process, there will still be silicon powder residue due to uncleanness' However, if the water pressure is too high, stress damage will also occur on the wafer surface. Therefore, the water pressure must be properly controlled to prevent the above-mentioned defects from occurring. If the stone powder remains, in subsequent processes, such as wire bonding, it will affect the bonding strength between Au Wire and solder joints on the grain, and even more in the subsequent molding. During the (Molding) process, the resin in the packaging mold (Resin) impacts the aforementioned poorly-bonded gold wire solder joints, causing the quality problem, or due to the contamination of residual silicon powder, which causes the packaging resin and the surface of the crystal grains during the molding process. The adhesion is not good, which causes delamination to occur at its adhesion. [Objective of the Invention] In view of the above disadvantages, the main object of the present invention is to provide a method for effectively preventing the silicon powder from remaining on the surface of the crystal grain during the process of crystal grain cutting. '' Another object of the present invention is to clean the crystal grains with ultrapure water during wafer dicing. The method of the present invention can provide a barrier interface to avoid the direct contact between the ultrapure water and the surface of the crystals caused by cleaning. Destruction ^ \ Another object of the present invention is that during grain cleaning, the method of the present invention can provide a protective layer on the surface of the crystal grains to prevent the carbon dioxide water (CO Water) from directly eroding the surface of the crystal grains during the cleaning process to cause crystals. Grain corrosion affects subsequent processes and product quality. To achieve the above-mentioned head 66, Tailuo Minggu was born in HI 矣 & & 仏

Page 5 556280 Case No. 891243U V. Description of the invention (3) ± _____ η Correct the coating, and then send the coated coating wafer to the wafer cutting machine for wafer cutting 'and remove the die after cutting The coating layer on the surface, thereby coating the coating layer on the surface of the wafer, can prevent the silicon powder from remaining on the surface of the wafer during wafer dicing; and by removing the other coating layer on the surface of the wafer, Remove the Shi Xifan remaining on the surface of the coating. [Detailed explanation] Please refer to "Figure 2A", "Figure 2B" and "Figure 2c" are schematic diagrams of each step of the method of the present invention, as shown in the figure: First, as shown in Figure 2A It is shown that a layer of transparent material 9 with a suitable thickness is evenly coated on the surface of the wafer 1. The other coating layer 9 is made of polyimide (about 40 ° C heat resistance) and uniformly adhered. On the surface of the wafer 1; as shown in FIG. 2B, after the coating layer 9 is coated, the wafer 1 covered with the coating layer 9 is sent to a machine (not shown) for crystallization. In a circular cutting process, the wafer 1 is cut into individual crystal grains 1 1. At this time, the coating layer 9 is still attached to the surface of the crystal grains 1 1. As shown in FIG. 2 c, a thermal inspection solution or Hydrazine removes the other coating layer 9 on the surface of the crystal grains 11 which is composed of polyimide as a material and dissolves it to complete the cutting operation of wafer 1. In this way, when the above-mentioned wafer 1 covered with the other coating layer 9 is subjected to wafer cutting, since the coating layer 9 covers the front surface of the wafer 1, the silicon powder generated during the dicing process can be retained in the On the surface of the other coating layer 9, the silicon powder remaining on the other coating layer 9 can be removed together by the process of removing the other coating layer 9 by hot mash: solution or hydrazine, so that the silicon after cutting can be avoided. The situation that the powder remains on the surface of the die 1 1 occurs; furthermore, during the cutting process of the wafer 1 covered with the coating layer 9 and sent to the wafer cutting machine, it can be formed on the surface of the wafer 1

IH 556280 ___Case No. 89124314__Year Month_Day Amendment V. Description of the Invention (4) A barrier interface to prevent the ultra-pure water used for cleaning from directly contacting the surface of the wafer 1, thereby preventing the ultra-pure water from affecting the surface of the crystal grain 1 1 Stress damage occurs; and because the wafer 1 covered with the coating layer 9 described above is subjected to carbon dioxide water cleaning during the wafer cutting process, the surface of the coating layer 9 is isolated by the coating layer 9 attached to the surface of the wafer A protective interface can be established to avoid direct contact between the carbon dioxide water and the surface of the crystal grains 11 during the cutting process, which can reduce the phenomenon of grains and rot residues and improve the operability of subsequent processes. Another embodiment of the present invention is to use a method of covering and pasting to prevent the wafer surface from remaining silicon powder. Please refer to "Figure 3". The present invention is added to the previously known method of "Figure 1" Two steps, that is, after wafer 1 is fixedly bonded to the center of steel frame 3 through wafer patch 4, a first patch 6 at least larger than the surface area of wafer j is coated on the front surface of wafer stack, and then crystallized. Circular cutting 5 divides wafer 1 into individual dies, and after the dicing is completed, the first patch 6 is removed, and the dies attached to the adhesive tape 2 are sent to subsequent related processes to complete the process. One-stage procedure. Please refer to wafer dicing, or you can also have it stuck on the steel lifting and pasting one, and then carry out, please participate in the "5th process shown in the wafer frame of the 3rd tape tape wafer cut on the tape" Schematic diagram of "Figure 4", as shown in the figure: Paste 1 layer to 1 patch 6 on the front side, and wait for the hollow space to be pasted, and then fix the wafer 1 2 to fix the wafer 1 Cut 5 'and send the die on 2 to the next 5 A picture after cutting "," shown in Figure 5B, which shows that the present invention is another embodiment of the present invention. After the surface area of the wafer 1 is formed, the back surface of the wafer 1 and the steel frame 3 are set at the center of the steel frame 3, and the first patch 6 is removed for use in the process. Figure "," Figure 5C "steps of another embodiment

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_ _ Case No. SQ19 Heart V. Description of the Invention (5) Schematic diagram, as shown in the figure: First, as shown in Figure 5A, first carry out the circle mounting process, and place the back of wafer 1 at least larger than the wafer 1 The surface of the steel frame 3 is hollow, and the steel frame 3 is evenly adhered to the back of the wafer 1 with an adhesive tape 2 so that the wafer 1 can be fixed to the steel frame ^; At the end of the process, "on completion of wafer placement", a layer of polyimide or polyvinyl chloride (PVC) with a temperature resistance of 400 ° C is affixed to the front side of wafer 1 which has been placed on a steel j-frame 3. The first patch 6 is composed of a material, and at least one side of the first patch 6 has adhesiveness to provide proper adhesive force, so that the first patch 6 is evenly adhered to the front surface of the wafer 1; as shown in FIG. 5B As shown in the following, after the completion of bonding, the wafer 1 with the first patch 6 on its surface is sent to a wafer dicing machine (not shown) for cutting, so that the wafer 1 is cut into a plurality of pieces after being cut. Neatly arranged grains 1 1, at this time, the first patch 6 is still covering the surface of the cut grains 1 1 and the bottom surface of the grains 11 is also adhered to the adhesive tape 2 in the hollow of the steel frame 3 As shown in FIG. 5C, after the wafer 1 is cut, a second patch 8 having a higher viscosity than the first patch 6 is applied to the first patch covered on the front surface of the wafer 1. 6 surface, the second patch 8 has a surface area at least larger than that of the wafer 1, so that the first patch 8 on the surface of the wafer 1 can completely cover the first patch 6 on the surface of the wafer 1 and adhere to it. ; As shown in FIG. 5D, after the second patch 8 is pasted to the first patch 6, the removal operation is performed, the second patch 8 is removed and removed from the surface of the wafer 1, and the first The adhesiveness of the lower surface of the two patches 8 to the upper surface of the first patch 6 is greater than the adhesiveness of the lower surface of the first patch 6 to the front surface of the wafer 1, so that the second patch 8 moves away from the steel frame 3 When the surface of the wafer 1 is hollow, the first patch 6 is removed and removed. In addition, the above-mentioned first patch 6 can also be carried out in a wafer patch operation.

556280 -SS_8912431 £ V. Description of the invention (6) Before pasting the same operation on the wafer, such as the die 1 of the wafer patch, and then swallowing the top of the front of the Japanese yen 1-by this, when the above During the cutting operation, because of the first barrier interface, touch 'on the surface of the wafer or the first patch 6 and stick to a patch 6 and remove the surface of the patch 6; geve powder 1 1 surface situation send 1 into the barrier interface of the wafer cutting machine, prevent cleaning The acidic dioxide surface, the crystal is covered with a piece of cloth with a piece of cutting instead of the first and second; the cutting can provide the phenomenon of rotten grain surface, which can improve only the above mentioned. It is within the scope of equivalent variations that define the true scope of the invention. Circle 1 washing crystal), the carbon water surface will only be applied and repaired later. The circular cut 2 patch 6 will be removed during the first patch 6 covering process and the cut patch 6 patch 8 will be removed. Furthermore, the super The pure water surface is sent to the wafer 1 table. The scope of the present invention, which is related to the die protection process, is to complete the correction operation, and then proceed to 'divide the wafer 1 into 8 pieces through the same process. The second process of sticking to the cloth 6 covered by the crystal is the second process of the post-cut crystal, which can be used for the above-mentioned paste, which can be directly connected to the stress-cutting circular cutting surface. Silicon powder still on wafer 1 on the front of circle 1 can be granulated. 1 1 surface patch 8 stickers, which can prevent the residual silicon powder from the first patch wafer 1 surface contact wafer 1 damage; machine cutting cleaning cloth 6 This can be reduced directly by the embodiment. According to the present invention, the wafer is specifically formed according to the present invention, so that it is left on the surface and directly covers the first remaining on the wafer 6 wafer surface. Because in the process Avoid touching 'by die 11 has, when it is not covered by patent Lee

Page 9 556280 _Case No. 89124314_Year Month Day_A simple explanation of the revised drawing [Simplified description of the drawing] The first drawing is a conventional wafer cutting flow chart. 2A drawing 2B drawing and 2C drawing Fig. 5 is a schematic diagram of each step of the method of the present invention. Fig. 3 is a schematic diagram of a second wafer cutting process according to another embodiment of the present invention. Fig. 4 is a schematic diagram of a second wafer cutting process according to another embodiment of the present invention. Fig. 5B, Fig. 5C and Fig. 5D Fig. 9 are schematic diagrams of each step of another embodiment of the method of the present invention. [Description of Symbols of the Drawings] Wafer 1 Tape 2 Steel Frame 3 Wafer Patch 4 Wafer dicing 5 First patch 6 Die 1 1st—-One patch 8 Overlay .. 9

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Claims (1)

556280 June 2 3 Case No. 89124314, patent application scope, a step of preventing silicon powder residue after wafer dicing: method, which includes the following 3) coating a coating layer on the wafer surface · b) will be coated with this The crystals of the overlying layer " wafer, and sent to the wafer cutting machine to cut the C) After the wafer is cut, the wafer table is removed, and the wafer is cut by covering the second: · It can prevent the silicon powder from remaining on the slope coating on the surface when dicing the wafer. The slope coating on the round surface is also removed when the surface is removed, and the powder is removed as described in the patent application. The remaining method, wherein the slope covering layer is made of silicon powder residue after circular cutting ^ The protection described in item 1 of the scope of patent application is made of material. The remaining method, where the coating is: = silicon powder residue after circular cutting, as described in item i of patent application scope, where f is composed of polyimide. The remaining method is to cover the "two: only the silicon powder residual amines are dissolved after wafer dicing. The layer removal method is to use hot alkali solution or combined 4