TWI306532B - Chip-on-glass process, thermal compression process and device thereof - Google Patents

Description

I3065S^8twf.doc IX. Description of the Invention: [Technical Field] The present invention relates to a packaging apparatus and process, and more particularly to a flip-chip glass process and a hot pressing process and apparatus therefor. [Prior Art] In the semiconductor industry, the production of integrated circuits (ICs) is mainly divided into three stages: the design of integrated circuits, the fabrication of integrated circuits, and the packaging of integrated circuits. The bare wafer is completed by steps of wafer fabrication, circuit design, mask fabrication, and wafer dicing, and each bare wafer formed by wafer dicing is via a pad on the bare wafer ( After the B〇nding pad is electrically connected to the external signal, the bare wafer is coated with a sealing material. The purpose of the package is

Early packaging technology? Using wire bonding and printing as a carrier chip

The technology is also constantly moving toward miniaturization and high density (LCD Pan Bonding, and, for a printed circuit board (Printed Circuit Boaul,

The package substrate, however, has the disadvantage of being manufactured with the type of thunder and A. LCD panel

- The volume of the structure, and mention 1306532 n «8twf.d〇c = line accumulation degree' recently developed the chip-on-glass (COG) packaging technology. FIG. 1A to FIG. 1B are schematic side views showing a hot pressing process in a conventional flip-chip glass packaging technique. Referring to FIG. 1A, the flip-chip glass packaging technology covers the wafer 104 having the bumps 106 over the contacts 102 of the glass substrate 100 and disposing an anisotropic conductive film between the wafer 104 and the glass substrate 100. (Anisotropic Conductive Film, ACF) 108, which is further subjected to a hot pressing process by the thermal head 110 to press the wafer 10 to the glass substrate 100, thereby making the bumps 106 electrically conductive by the anisotropic conductive film 108. Connect to contact 1〇2. During this hot pressing process, the rubber material in the anisotropic conductive film 108 will cure and shrink, thereby providing a suitable tensile force to press the bumps 1〇6 and the contacts 1〇2, and forming a rigid structure to resist external forces. The impact. Referring to FIG. 1B, the thermal head 11A is removed to cool the wafer 1〇4 and the glass substrate 100. However, after the hot pressing process, most of the thermal stress remains in the element, causing the glass substrate 1 to be deformed (as shown in Fig. 1B), which in turn causes the display to cause defects on the panel. At present, the methods for solving the above problems generally include lowering the hot pressing temperature, reducing the temperature gradient in the structure during thermocompression, improving the matching of the thermal % expansion coefficient of the materials of the respective components, shortening the length of the wafer, and changing the flip-chip bumps and The geometry of the structure of the square conductive film and the like. However, with the current technology, the above five methods still have their limitations. For example, to reduce the temperature of the hot press, it is necessary to use an anisotropic conductive film with a lower curing temperature or other anisotropic conductive film that is not thermally cured. Reducing the temperature gradient within the structure requires an increase in the cost of the device. Improving the coefficient of thermal expansion matches I3〇65^8twfdoc requires appropriate materials to be replaced. The shortening of the wafer length is in conflict with the current trend of increasing the resolution of the display. .

Therefore, the solution that is currently used more often is to heat the wafer and the glass substrate in a non-stress condition after the hot pressing process, so that the colloid between them is softened and creeped, thereby making the wafer and the wafer The broken substrate rebounds from the original shape. However, this method requires a long process time and a high equipment cost. It can be seen that the cracking process technology of flip-chip glass breaks through the demand. T [Invention] The glazing process may be of poor quality or, therefore, the object of the present invention is to provide a flip chip to prevent the display panel from being deformed after the process to cause display defects. Another object of the present invention is to provide process controllable factors that in turn improve process reliability and component quality.曰π θ A further object of the present invention is to provide a hot pressing device which provides a pre-strain of a component to be pressed to compensate for the strain generated after the thermocompression stress is removed. The present invention provides a flip-chip process in which a panel and a wafer are provided, wherein the panel has a first joint surface and two have at least one joint. The wafer has a second joint surface and this second surface has at least a bump. The wafer gi is then placed on the panel: the bump pairs are located at the junction. Then, a hot pressing process is performed to apply the stress and stress of the wafer and the panel so that the second joint surface of the panel is formed into a curved surface and the bump is electrically connected ^ = 1306532 Kiss 8twf.doc point O y. Thereafter, the hot compressive stress is removed from the wafer and the panel. In particular, after the wafer and the panel are cooled and cooled, the first bonding surface of the wafer and the second bonding surface of the panel respectively form a plane, for example. The present invention provides a hot stamping process which first provides a first component and a second component, wherein the first component has a first bonding surface and the second component has a second bonding surface. Then, the first component is disposed on the second component, and the first component and the second component are subjected to a compressive stress so that the bonding surface of the first component and the second bonding surface of the second component respectively form a curved surface. It is to be noted that after the compressive stress is removed, the first joint surface of the first member and the second joint surface of the second member, for example, respectively form a plane. The present invention also provides a hot pressing apparatus comprising a first indenter and a second indenter. The first indenter has a first curved surface, and the second indenter has a second curved surface for pressing the two elements together with the first curved surface of the first indenter. The radius of curvature of the first curved surface and the second curved surface is, for example, dependent on the amount of strain generated by the components and the thickness of the elements.

The invention provides a component pre-variable by a curved head with a curved surface during the hot pressing process to compensate for the strain caused by the difference in thermal expansion coefficient of the component after the stress is removed from the component after the thermocompression stress is removed. Reduce the amount of deformation of the piece. Therefore, the sealing of the flip-chip glass by the invention can avoid deformation of the panel after the packaging process, thereby improving the yield of the panel. The above and other objects, features, and advantages of the invention will be apparent from the description of the appended claims. 》, ', 田呪 f3 8twf.doc [Embodiment] The present invention is to produce a pre-variable in the hot pressing process of the component to be pressed, the pre-strain will make the pressing component have a curved joint surface, so that To compensate for the amount of deformation produced by these components after the thermocompression stress is removed. The following examples are illustrative of the present invention by way of a flip-chip glass process, but are not intended to limit the scope of application of the present invention. Those skilled in the art will appreciate that the present invention is also applicable to hot press processes in other fields. 2A-2C are schematic side views showing the flow of a flip chip process using a preferred embodiment of the present invention. Referring to Fig. 2A, the wafer 220 is first placed on the panel 210. The panel 210 has a first joint surface 212 and at least a joint 214 on the first joint surface 212. The wafer 220 has a bonding surface 222, and the second bonding surface 222 has at least one bump 224. It should be noted that when the wafer 220 is disposed on the panel 210, the bumps 224 are aligned at the contacts 214. In an embodiment, the panel 210 is, for example, a display panel, which is, for example, a liquid crystal display panel. The wafer 220 is, for example, a driving wafer for driving a display panel. In another embodiment, for example, a conductive film 2 () 8 having heat curing characteristics is disposed between the panel 210 and the wafer 220 for caulking the panel 21 and the wafer 220. Moreover, the bump 224 can be electrically connected to the contact 2M through the conductive film 2〇8. In a preferred embodiment, the conductive film is, for example, an anisotropic conductive film. Then, a hot pressing process is performed to press the panel 21 and the wafer 22 to. In particular, the hot pressing stress applied to the panel 21 and the wafer in the hot pressing process causes the first bonding surface 212 of the panel 210 and the second 130653⁄4 8 twf. doc bonding surface 222 of the wafer 22 to be changed from a plane to a curved surface. , as shown in Figure 2B. In a preferred embodiment, the hot stamping used in the hot stamping process includes, for example, a first indenter 200 and a second indenter 202 (shown in FIG. 3) to apply heat to the wafer 220 and the panel 210. Compressive stress. The first indenter has a first curved surface 204, the second indenter has a second curved surface 206, and the second curved surface 206 of the second indenter 202 is pressed together with the first curved surface 204 of the first indenter 200 to bond the wafer 220. With panel 210. In the above, the radius of curvature of the first curved surface 204 of the first indenter 200 and the second curved surface 206 of the second indenter 202 depends, for example, on the thickness of the component to be pressed and its dependent variable, so the first curved surface 204 and the first surface The curvature radius of the two curved surfaces 206 may be the same, or may be slightly different due to the elasticity of the conductive film 208, the bumps 224 or the contacts 214, and a detailed description thereof will be described later. Referring to FIG. 2C', if the conductive film 208 is used, the hot compressive stress can be removed from the wafer 22 and the panel 210 after the adhesive in the conductive film 208 is cured. After the thermocompression stress applied to the face plate 21 and the wafer 220 in the heat-removal process is removed, the first joint face 212 of the face plate 21 and the second joint face 222 of the wafer 220 will return to a flat surface. It is worth noting that the so-called "plane" here refers to a surface whose radius of curvature is close to infinity, but does not limit its radius of curvature to infinity. Referring to FIG. 3, in a preferred embodiment, when the first ram 2 〇〇 and the second ram 202 are pressed against the wafer 220 and the panel 210, the first δ plane 212 and the second joint surface are There is a pre-variable of the direction 2〇1 (that is, the long-axis direction of the wafer) shown in FIG. 2c, and the pre-strain I306533238twf.doc amount includes the first curved surface 204 and the second of the first pressure 200. The curvature radius of the second curved surface 2〇2 of the indenter 202 is a strain amount caused by 2〇1 in the longitudinal direction of the wafer, and the temperature gradient is caused by the strain in the longitudinal direction 201 of the wafer. A special 疋' this pre-requisite can be used to compensate for the amount of strain produced by the wafer 22 and the panel 21 after hot pressing. It can be seen that the total strain amount produced by the first joint surface 212 of the panel 210 after the hot compressive stress is removed, for example, the total strain f produced by the joint surface 222 of the day sheet 220 at this time. Therefore, the panel 21 of the present invention does not undergo deformation after the hot pressing process, as shown in Fig. 2C. Hereinafter, taking the above-mentioned flip-chip glass process as an example, the first curved surface 204 of the first indenter 2 and the second curved surface 206 of the second indenter 202 of the hot pressing device of the present invention are tested by a simplified hypothesis model. The radius of curvature. It is to be noted that the following embodiments exemplify two kinds of strains which may be generated by the face plate 21 and the wafer 22, and thereby calculate the radius of curvature of the first curved surface 2〇4 and the second curved surface 2-06. However, the present invention does not limit the radius of curvature of the second curved surface 204 of the first indenter 2 (9) and the second curved surface 2〇6 of the second indenter 202, as described in the following embodiments. The main spirit of the present invention is that the temperature distribution and the layered geometry at the time of pressing determine the most appropriate radius of the first curved surface 204 of the first indenter 2 and the second curved surface 2〇6 of the second indenter 202. 'Therefore, those skilled in the art can modify the actual formula of the process according to the following formula. However, it should still belong to the scope of the invention. For convenience, the state A and the state B are defined first. status. Here, the state a indicates that the hot stamping process has not been performed. The panel 210 is separated from the wafer 220 at this time, so that no stress exists between the two, and the panel 210 and the wafer 220 are both at a uniform normal temperature. In other words, the surface of the panel 210 and the wafer 220 in the state A are both planar. State B represents the time at which the hot stamping process is performed, so in state B, the contours of panel 210 and wafer 220 will be limited by the curved first indenter 200 and second indenter 202, while the first indenter 2〇 The temperature on the crucible and the second indenter 202 will result in a uniform temperature gradient across the panel 210 and the wafer 220, respectively. State C indicates the end of the hot stamping process, and the temperature of panel 21 and wafer 220 has dropped back to normal temperature. Therefore, in the state c, the panel 21 〇 Φ and the temperature in the wafer 220 are uniform normal temperatures. As can be seen from the above, in the state C, there is no residual stress on the first bonding surface 212 and the second bonding surface 222 of the panel 210 and the wafer 220, and the panel 210 and the wafer 220 in the state A and the state C are Panel 210 is identical to wafer 220. Therefore, by calculating the strain between the two joint states (A state and B state or 疋B state and C state) of the first joint surface 212 and the second joint surface 222, respectively, and making them equal, it is possible to obtain an ideal In the case (that is, the panel 21 in the state A and the wafer 21 and the panel 21 in the state C are the same as the wafer 22), the first indenter 200 and the second pressure used in the hot pressing and the crucible The radius of curvature of the head 2〇2. Referring to FIG. 2C, first, & is the first joint surface 212 of the panel 21, the total strain generated by the state B into the state C, and & is the wafer 22 〇 = the second joint surface 222 is from the state B Enter the total strain ink produced by state c. It can be seen from the above. When the amount of misalignment of the first joint surface 212 and the second joint surface 222 is zero, it means that there is no residual stress between the panel 21A and the wafer 220 when entering the state C from the state B. Therefore, v must be equal to &<<>> according to the principle of superposition in material mechanics, the total strain & of the first joint surface 212 of the panel 210 can be decomposed into: ~: first joint surface 212 when the state b enters the state C, the strain due to the temperature change ^: when the first joint surface 212 enters the state c from the state b, due to the removal of the solitary first head 200 and the second head 202 Remove the resulting dependent variable

Where ' and \ is the expansion coefficient of the panel 210, C is room temperature, and 5 is the temperature of the first joint surface 212 of the center of the panel 21〇 in the state B (that is, during the hot pressing process), and here ^ Simplified estimation is the average of the temperature of the 'conductive film 2〇8' and the surface temperature of the second indenter 2〇2 in the state B. Further, '~ indicates the amount of strain generated by the first joint surface 212 of the panel 210 after the first indenter 200 and the second indenter 202 are removed. Wherein, in a general application, since the thickness of the wafer 220 and the panel 210 is much smaller than the radius of curvature of the first joint surface 212 and the second joint surface 222, all the structures of the element and the first curved surface 2〇4 and the second can be The radius of the curved surface I〇630^38twf.doc of the surface 2〇6 is considered to be the same. Referring to FIG. 4, point p is the center of curvature of the first joint surface 212 of the panel 210, 0 is a small angle, and the center length of the panel 210 is Μ, and the length of the first joint surface 212 of the panel 210 is: Say:

Here, the compressive stress applied to the panel 210 by the first indenter 200 and the second indenter 202 causes the length of the first joint surface 212 of the panel 210 to have a strain s r 〇 {i + ε with respect to the center length of the panel 210.

While the first engagement surface 212 of the strainer panel 210 described herein enters the state Β by the state ,, the first engagement surface 212 is the amount of strain generated when the state B enters the state C. and so,

K £p2=~Yr where & is the thickness of the panel 210, and r is the radius of curvature of the first curved surface 204 and the second curved surface 206. Similarly, from the above principle, the total strain of the wafer 220 is: and ecl = ac (Tr - Tc) _ Κ s 2 = - c2 2r where A is the expansion coefficient of the wafer 220, \ is the thickness of the wafer 220, Ι 3065 2? and 7; indicates the temperature of the second joint surface 222 at the center of the wafer 220 in the state B. It should be noted that the length of the second joint surface 222 of the wafer 220 in the shape C is longer than the length in the state b, and the length of the first joint surface 212 of the panel 210 in the state C is longer than the state thereof. The length in b is short, so the ~ system is opposite to the radius of curvature r, and the heart is the same as the radius of curvature r. Then 'order~ you can find the radius of curvature:

K + hP - In the embodiment, if the panel disk == press process at room temperature of 25 degrees Celsius, where the thickness of the panel is 7 〇〇 _, the thickness of the wafer, the temperature at the center of the panel is 廑 39.8 摄, Two η, 丄 is 209.8 ° Celsius. In addition, the thermal expansion coefficient of the wafer and the thermal expansion coefficient of the panel is 4.7ppm / 〇c = the number is 4. sterol / C, the formula can be obtained to obtain the radius of curvature r. Some parameters are brought into the above example. 'Using heat g5m with a radius of curvature of 2.5 m. Therefore, deformation occurs after this hot pressing process. ',,, and can avoid the panel. It is worth noting that although the curvature of the curved surface of the above embodiment and the second curved surface of the second indenter is the first method of the first indenter, the simpler calculation method is used for explanation. , ^ is phase 2, but the radius of curvature of the first surface of the value must be equal to the first limit and the radius of curvature. Those skilled in the art can rely on the second surface of the surface and the first surface of the first and the first of the first. The invention provides the component deformation during the hot pressing process. . Therefore, this issue: Glass::: I3065^8twf-doc can avoid deformation of the panel after the heat county, and increase the yield of the panel. x mad And, as can be seen from the foregoing description, the radius of the curved surface in the hot pressing apparatus of the present invention can be adjusted according to the operating temperature of the heat (four) steps so as to not deform at any operating temperature. Therefore, in the process of the present invention, the temperature can be raised to reduce the pressing time, thereby increasing the thermal curing reaction rate of the film and improving the reliability of the product. Although the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the invention, and the present invention may be modified and modified without departing from the scope and scope of the invention. The scope of this application is subject to the definition of the scope of the patent application. /'δ [Simple Description of the Drawings] Fig. 1 to Fig. 1A are schematic side views showing the hot pressing process in the conventional flip-chip glass packaging technology. 2A to 2C are schematic side views showing the flow of a flip chip process using a preferred embodiment of the present invention. Figure 3 is a schematic side elevational view of the hot press process using the hot press process of the present invention. 4 is a schematic side view of a panel in accordance with an embodiment of the present invention. [Description of main component symbols] 100: glass substrate 102, 214: contacts 104, 220: wafers 106, 224: bumps 108: anisotropic conductive film I3065^8twf.do 110: indenter 200 · · first indenter 202: second indenter 204: first curved surface 206: second curved surface 208: conductive film 210: panel 212: first joint surface 222: second joint surface

Claims (1)

1306532 97-06-03 曰修 (more) is replacing page 10, applying for a patent garden: 1. A flip-chip glass process 'includes: providing a panel having a first bonding surface, and having at least one contact on the bonding surface; providing a wafer Having a second bonding surface, and having at least one bump on the second bonding surface; arranging the wafer on the panel such that the bump is located at the contact; performing a hot pressing process to apply The wafer and the panel 1 are hot pressed to stress the joint and the bump, and the first joint surface of the panel and the second joint surface of the wafer respectively form a curved surface; In addition to the hot pressing stress. 2. If the flip chip process described in the application of the full-time item, wherein the second wafer is disposed on the panel, the first conductive electric film is included in the panel, and the wafer is The bump is electrically connected to the panel of the panel by the film. The flip-chip process described in claim 2, wherein the film 4 comprises an anisotropic conductive film. Such as; in the process of compression, including a slap in the face - ε >: " Kang hot medicine master comprises a first and a second pressure ram administering COG process the first item of the scope of interest, wherein 1 = wafer and the panel, wherein the first indenter has - and the first indenter has a second curved surface. The method of flip-chip glass according to item 4 of the second patent, wherein, in the course of the garment, the curvature of the first surface and the second curved surface is 18 I3065?^38 tw, the diameter of the doc depends on the panel and The thickness of the wafer, the coefficient of thermal expansion and the temperature distribution, and the temperature difference between the first bonding surface and the second bonding surface during the hot pressing process and room temperature. 6. The flip-chip process of claim 1, wherein the first bonding surface of the panel and the second bonding surface of the wafer form a plane, respectively, after the thermocompression stress is removed. 7. A hot stamping process comprising: providing a first component and a second component, wherein the first component has a first bonding surface and the second component has a second bonding surface; Arranging on the second component; applying a compressive compressive stress to the first component and the second component to form the first bonding surface of the first component and the second bonding surface of the second component respectively a curved surface; and removing the hot compressive stress. 8. The hot press process of claim 7, wherein the step of applying the compressive stress to the first component and the second component comprises respectively: a first indenter and a second indenter Applying the compressive stress to the first element and the second element, wherein the first indenter has a first curved surface and the second indenter has a second curved surface. 9. The hot stamping process of claim 8, wherein the radius of curvature of the first curved surface and the second curved surface is dependent on thickness, thermal expansion coefficient and temperature of the first component and the second component And a temperature difference between the first bonding surface and the second bonding surface in the hot pressing process and room temperature. 10. The hot press process of claim 7, wherein the first bonding surface of the first component and the second bonding surface of the second component are respectively formed after the thermocompression stress is removed at 130653⁄43⁄4 a plane. 11. A hot pressing device comprising: a first indenter having a first curved surface; and a second indenter having a second curved surface, wherein the first curved surface and the second indenter of the first indenter The second curved surface is in contact with the two elements for pressing the two elements. 12. The hot pressing apparatus according to claim 11, wherein a radius of curvature of the first curved surface and the second curved surface is determined by thickness, thermal expansion coefficient and temperature distribution of the components, and the components are in the heat The temperature difference between the process and the room temperature during the pressing process. 13. The hot press apparatus of claim 11, wherein a radius of curvature of the first curved surface is the same as a radius of curvature of the second curved surface. 14. The hot press apparatus of claim 11, wherein a radius of curvature of the first curved surface is different from a radius of curvature of the second curved surface. 20