TW508777B - Stencil printing apparatus - Google Patents

Abstract

A kind of stencil printing apparatus is disclosed in the present invention, and includes a stencil body portion, a ring-shaped protrusion portion, a squeegee and the soldering material. The stencil body portion has the first scraping surface and an opening, in which the opening is used for placing the wafer. The ring-shaped protrusion portion is disposed at the inner wall of the opening and has an inner diameter smaller than that of the wafer. In addition, the ring-shaped protrusion portion has the second scraping surface, which is approximately at the same level as the first scraping surface, and forms an integrated molding with the stencil body portion. The squeegee and soldering material are disposed on the stencil body portion so as to fill uniformly the soldering material on the wafer surface by moving the squeegee back and forth on the first scraping surface and the opening. In addition, by using the ring-shaped protrusion portion, the flowing of soldering material through the edge and the bottom portion of wafer is effectively blocked for causing contamination so as to increase the yield of bumping process.

Description

508777

Field of the Invention: The UIR month is related to a printing device, and particularly to a kind of steel, which is used to prevent the solder paste from contaminating the bottom and the bottom of the wafer. Relevant technical description: Flip chip (FC) technology is one of the important emerging technologies in a semiconductor package (package) process. It has the advantages of small package size, short wiring, low inductance, and easy control of high frequency noise. . This flip-chip (FC) technology uses a plating or stencU printing process to form solder on a pad of a semiconductor integrated circuit, and then reflows ( ref i00w) process to form the solder ball into a solder ball. The above two process steps are called bump processes. Finally, the wafer is aligned with the substrate after being aligned by a flip-chip bonding machine. The following steps 1a to 1h illustrate the traditional process of forming bumps. First, referring to FIG. 1a, a protective layer, such as glass, is formed on a wafer 10 having a circuit (not shown) and an aluminum pad 12 formed thereon, and the surface of the pad 12 is exposed. A layer of under bump metallurgy (UBM) 16 is formed on the layer 14 and the exposed pad 12 surface, such as A1 / NiV / Cu, which is used to provide adhesion and prevent diffusion And improve solder wetting. Next, referring to FIG. 1b, a photoresist layer 18 is formed on the multilayer metal film 16. Next, referring to FIG. 1c, the photoresist layer 18 is patterned, and then the multilayer metal film 16 is etched to leave the patterned photoresist layer 18 and the multilayer metal film 16 at a position above the pad 12.

777 V. Description of the invention (2) —111 —-- Next, please refer to Figure 丨 d. After removing the patterned photoresist layer 18, the protective layer 14 and the patterned multilayer metal film 6 A negative resist layer 20 is formed, such as a dry film resist (dfr). Next, referring to FIG. Le, pattern the negative resist layer 20 to remove the negative resist layer 20 above the patterned multilayer metal film 16 and form openings 20a. Then, refer to 1f In the figure, the wafer i 0 when the above steps are completed is placed in a stencil printing device (not shown) to fill the solder 101, for example, into the opening 20a. ^ Next, please refer to Figure 1 § to remove the remaining negative resist layer 20. Finally, referring to Figure lh, the wafer when the above steps are completed is placed in a reflow oven (not shown) to form the solder 101 into a solder ball 1013, that is, a bump. However, please refer to FIGS. 2 and 3, which respectively show a plan view of a conventional stencil printing apparatus and a cross-sectional view of the stencil printing apparatus along A-A in FIG. 2. When the bump printing process is performed by the stencil printing method, because the internal diameter of the opening 102a of the steel plate main body portion 102 in the printing device is slightly larger than the diameter of the wafer 100, a small gap is formed, that is, in FIGS. 2 and 3 Mark g, so when the rubber 101 is filled with the solder 101 on the wafer 100 by the rubber blade (squeegee) moving back and forth (as indicated by the arrow direction in Fig. 2) (as in the step of Fig. 1), The solder 101 easily flows into the gap g and contaminates the edge and the bottom of the wafer 100. In this way, during the heavy-flow process, the wafer 100 easily adheres to the wheel belt (not shown) of the heavy-flow furnace, which causes the front and rear wafers i00 to push against each other and cause fragmentation, which results in yield reduce. In addition, even if the wafer 100 is contaminated and not broken, the wafer will be 10 () due to the solder on the bottom.

// / 5. Description of the invention (3) The surface is not flat, which affects the applications that can be applied to high-density sealing ratios. Therefore, in view of this, the opening of the steel plate body and a ring body portion is provided with a solder to contaminate the wafer. Summary: The purpose of the present invention is to prevent the solder from contaminating the reflow (ref low rate) of the subsequent encapsulation process when a ring-shaped protrusion is used. Due to the flip-chip bonding and assembly process, this technology is used in The problem will be extremely high in the future, and it is necessary to solve this problem. The invention provides a stencil printing device, including: a protrusion and a scraper, which prevent the gap from occurring by preventing the edge and Bottom. It is to provide a stencil printing device by performing the stencil printing process (stencii printing on the edges and the bottom of the wafer. The purpose is to provide a stencil printing device in the subsequent process) to prevent wafer breakage and reduce the yield. Purpose, the present invention is used on a wafer, including a steel, a first scraping surface and an opening for an annular protrusion, The opening is smaller than the diameter of the wafer; and a scraper blade is formed on the first scraping surface and the opening and the first scraping surface is substantially flush with the first as a whole. Furthermore, the steel is placed on the first scraping surface for borrowing. Therefore, the solder material is tin-lead alloy and Ximing provides a stencil printing device adapted to the plate body portion. The steel plate body portion has the wafer completely placed in the opening; the inner wall, wherein the inner diameter of the annular protruding portion is set at The steel plate body portion is used for moving. Among them, the annular protruding portion has a scraping surface, and the annular protruding portion and the plate printing device of the steel plate further include a solder, which is placed on the surface of the wafer by a knife. Among them, the wrong percentage is 63: 37.

508777 V. Description of the invention (4) Brief description of the drawings: In order to make the above-mentioned objects, features, and advantages of the present invention more comprehensible, the preferred embodiments are described below in detail with the accompanying drawings, as described in detail below. : Figures 1a to 1h are schematic cross-sectional views of conventional bumps. Fig. 2 is a plan view showing a conventional stencil printing apparatus. Fig. 3 is a sectional view of the stencil printing apparatus taken along A-A 'in Fig. 2; Fig. 4 is a plan view showing a stencil printing apparatus according to the present invention. Fig. 5 is a sectional view of the stencil printing apparatus taken along B-B 'in Fig. 4 according to the first embodiment of the present invention. Fig. 6 is a sectional view of the stencil printing apparatus taken along B-B 'in Fig. 4 according to the second embodiment of the present invention. [Symbols] 10, 100, 2 0 ~ wafers; 12 ~ pads; 14 ~ protective layers; 16 ~ multilayer metal thin films; 18 ~ photoresist layers; 2 ~ negative resist layers 20a, 102a, 203 ~ opening; 101, 201 ~ solder; 101a ~ solder ball;

0503-7103twf; TSMC2001-1085; spin.ptd page 8 508777

102, 202a ~ steel plate body; 104, 204 ~ scraper; 202 ~ printed steel plate; 202b ~ annular protrusion; 205a, 205b ~ scraping surface ° Detailed description of the preferred embodiment: The following two embodiments The first and the first stencil printing apparatuses of the present invention will be described with reference to Figs. 4, 5, and 6. First, please refer to FIG. 4, which shows a plan view of a steel plate brush device according to the present invention. It is shown that 2000 is a crystal mesh. There are pads, protective layers, multilayer metal films, and negative resist layers on the wafer 2000. As shown in Figure ^, here is a simplified diagram #, only A leveling table is shown, and the state when the wafer 200 is placed is represented by a broken line. The stencil printing device of the present invention includes a steel plate body portion 202a, an annular protruding portion 202b, a scraper blade 204, and a solder 201. In the present invention, the scraper blade 204 is made of rubber. In order to prevent the scraper blade from scratching the negative resist layer (not shown) on the surface of the wafer 2000 when moving back and forth, and the solder 201 used in the present invention, for example, The solder paste is a tin-lead alloy, and its tin: lead weight percentage is 63 ·· M. '' The surface of the steel plate body 202a is the surface of the scraper 205 to the surface 205a, and has an opening 203 whose inner diameter is slightly larger than the diameter of the wafer 200, so that the wafer 2000 can be completely placed in the opening. Within 203. Next, the annular protruding portion 202b is disposed on the inner wall of the opening 203 so that the inner diameter of the annular protruding portion 2021) is smaller than the wafer diameter. Next, the scraper blade 204 and the solder 201 are provided on the steel plate main body portion 002a ', that is, on the scraping surface 2 05a', for scraping the blade 2 0 4 on the scraping surface 2 0 5 a and the

508777 V. Description of the invention (6) The opening 203 is moved back and forth (the direction of the arrow is marked in the figure) to fill the surface of the wafer with solder 201. Next, please refer to FIG. 5 to describe the first embodiment of the present invention. The figure shows a cross-sectional view of the stencil printing device along B-B 'in FIG. 4. In this embodiment, the surface of the annular protrusion 202b is also the scraping surface 205b of the scraper blade 204. This scraping surface 205b is substantially flush with the scraping surface 205a described above, and the cross-section of the annular dog exit portion 20b is uniform. The rectangle is such that the long side of the rectangle coincides with the scraping surface 205, and the short side is adjacent to the inner wall of the opening 203. In addition, the annular protruding portion 202b is integrally formed with the steel plate main body portion 202a to constitute the printed steel plate 202 of the present invention. In this way, when the stencil printing device is placed in the wafer, there is no problem that the conventional stencil printing device generates a gap and causes the solder 2001 to contaminate the edge and bottom of the wafer 2000. In this embodiment, if the long side of the rectangle is too long, it is easy to shield the effective pad (not shown) adjacent to the edge of the wafer 200 and the solder 201 cannot be formed on the pad smoothly; if the long side is too short, it is easy Gap occurs at the edge of the wafer and contamination problems occur, so the length of the long side of the rectangle is in the range of 1 to 2 centimeters (mm). Similarly, if the short side of the rectangle is too long, the height difference between the scraped surface 205b and the wafer surface is too large, making it difficult to uniformly fill the solder 201 on the wafer surface, so the short side of the rectangle does not exceed 0.05 cm. In addition, because the solder paste 201 used here has a high viscosity, it can still be uniformly filled on the wafer with a height difference of 0.05 cm. Next, please refer to FIG. 6 to explain the second embodiment of the present invention, which is a cross-sectional view showing a plate printing arrangement along B-B 'in FIG. 4. In this embodiment, the difference from the first embodiment is that the cross-section of the annular protrusion 2 q 2 b is a right-angled triangle. The base and scrape of one of the right triangles

0503-7103twf; TSMC2001-1085; spin.ptd page 10 508777 V. Description of the invention (7) 205b coincides while the other bottom edge is adjacent to the inner wall of the opening 203. Similarly, the reason that the length of the bottom edge that coincides with the face 205b is 1 to 2 cm is the same as that described in the first embodiment; the length of the other bottom edge adjacent to the inner wall of the opening 203 is less than The thickness of the steel plate body 20a. In this way, the edge of the wafer 200 will contact the hypotenuse of the right-angled two corners, and similarly, the pollution problem caused by the gap is avoided. Therefore, according to the present invention, the yield of the wafer edge is effectively prevented and the ring-shaped protruding shape is increased in the subsequent sealing embodiments. However, the present invention is not limited to the present invention. Any familiarity and scope can be used as When attached, the patented π heart cymbal plate brushing device can avoid the generation of fierce gaps and contamination of the bottom, thereby improving the reliability of the bump manufacturing process. In addition, in the present invention, the section 202b has a rectangular and right-angled cross section, which are limited to this, and may be fan-shaped, trapezoidal, or the like. The preferred embodiment is disclosed above, but it is not used by those skilled in the art, but can be used without modification and retouching without departing from the present invention. Min + * yu nB > The scope defined shall prevail. Blunt garden

Claims (1)

508777 6. Scope of patent application 1. A stencil printing device suitable for a wafer, including a steel plate body portion, the steel plate body portion having a first scraping surface and an opening 'for completely placing the wafer Placed in the opening; an annular protrusion provided on the inner wall of the opening, wherein the inner diameter of the annular protrusion is smaller than the diameter of the wafer; and a scraper provided on the steel plate body portion for the first scraping surface Move up and down the opening. 2. The stencil printing device according to item 1 of the scope of patent application, wherein the annular protruding portion is integrally formed with the steel plate main body portion. 3. The stencil printing device according to item 1 of the scope of patent application, wherein the annular protruding portion has a second scraping surface substantially flush with the first scraping surface. 4. The stencil printing device described in item 1 of the scope of patent application, further comprising a solder placed on the first scraping surface for filling the wafer surface by the scraper. 5. The stencil printing device according to item 3 of the scope of patent application, wherein the cross-section of the annular protrusion is a rectangle, and the long side of the rectangle coincides with the second scraping surface. 6. The stencil printing device as described in item 3 of the scope of patent application, wherein the cross-section of the annular protrusion is a rectangular corner, and the first bottom edge of the right-angled triangle coincides with the second scraping surface and the second bottom edge Adjacent to the inner wall of the opening. 7. The steel stomach plate printing device as described in item 4 of the scope of patent application, wherein the solder material is a tin-lead alloy and the tin: lead heavy cover percentage is 6 3: 37. 8. The stencil printing device described in item 5 of the scope of patent application, wherein 508777