TWI392906B - Display panel having bump structure for test and method of examining chip bonding condition of display panel - Google Patents

Description

Display panel having bump structure for detecting and method for detecting wafer bonding state of display panel

The present invention relates to a display panel having a bump structure for detecting and a method of detecting a wafer bonding state of a display panel, and more particularly to a display panel having a decreasing bump horizontal cross-sectional area design for detecting a bump structure, which can be quantified The result of the wafer press-fit state of the display panel.

The COG (chip on glass) technology refers to a technique of bonding a wafer directly to a connection pad on a glass substrate, and since COG technology has a low cost advantage, it has been widely used in wafer bonding production of a display panel. The current COG technology mainly includes the use of metal welding and anisotropic conductive adhesive (ACF). However, under the condition that the density of the line layout is increasing, the above two COG technologies have limitations in layout density and are prone to short-circuit problems. .

Recently, a technique of bonding a wafer and a display panel using a non-conductive adhesive has been proposed. However, in the process of performing a bonding process of a conductive bump and a connection pad, it is difficult to determine the conductive bump using a technique of bonding a wafer and a display panel using a non-conductive adhesive. The bonding condition between the block and the connection pad, so its yield and reliability have to be further improved.

It is an object of the present invention to provide a display panel having a bump structure for detecting and a method of detecting a wafer bonding state of the display panel to improve the yield of the pressing process and the reliability of the display panel.

In order to achieve the above object, the present invention provides a bump structure for detection. The detecting bump structure is disposed on the wafer, and the detecting bump structure includes a pedestal and a reflective film. The pedestal is disposed on the surface of the wafer, the pedestal has a bottom, a top and a side, and the pedestal has a decreasing horizontal section cross-sectional area from bottom to top. The reflective film is disposed on the top and sides of the base.

To achieve the above object, the present invention provides a display panel having a bump structure for detection. The display panel includes a light transmissive substrate, a wafer, and a non-conductive colloid. The light transmissive substrate includes a detection area. The wafer includes a bump structure for detection corresponding to a detection region of the light-transmitting substrate. The bump structure for detection includes a susceptor and a reflective film. The pedestal is disposed on the surface of the wafer, the pedestal has a bottom, a top and a side, and the pedestal has a decreasing horizontal section cross-sectional area from bottom to top. The reflective film is disposed on the top and sides of the base. A non-conductive colloid that adheres the wafer to the light-transmissive substrate. The reflective film on the top of the pedestal is pressed against the surface of the transparent substrate by adhesion of the non-conductive colloid to the wafer.

In order to achieve the above object, the present invention provides a method for detecting a wafer bonding state of a display panel, comprising the steps of: providing a light-transmitting substrate including a detecting region; providing a wafer, the wafer including the detecting bump structure, and the detecting bump structure The method includes a base disposed on a surface of the wafer, the base has a bottom, a top and a side, and the base has a decreasing horizontal sectional area from the bottom to the top; and a reflective film disposed on the top and the side of the base; The detecting bump structure corresponds to the detection area of the transparent substrate, and then the non-conductive colloid is used to adhere the wafer to the front surface of the transparent substrate, and the wafer is subjected to a pressing process to deform the base of the detecting bump structure. And performing a detection process, and observing the area of the reflective film located at the top of the pedestal from the back side of the transparent substrate to determine the pressing effect of the sizing process.

In order to achieve the above object, the present invention provides a method for fabricating a bump structure for detecting, comprising the steps of: providing a wafer; forming a photosensitive material layer on the wafer; and exposing and developing the photosensitive material layer by using a gray scale mask, To form a pedestal, wherein the pedestal has a bottom, a top and a side, and the pedestal has a decreasing horizontal kerf cross-sectional area from bottom to top; and a reflective film is formed on the top and sides of the pedestal.

The invention utilizes the detection bump structure with the decreasing horizontal section sectional area design, can quantify the result of the pressing process, thereby confirming whether the pressing of the conductive bump structure and the connection pad is effective, and avoiding excessive pressing or The problem of insufficient press-fitting can effectively improve the yield of the press-bonding process and the reliability of the wafer bonding structure of the display panel.

The present invention will be further understood by those skilled in the art to which the present invention pertains. The effect.

Please refer to Figures 1 to 3. 1 to 3 are schematic views showing a method of fabricating a bump structure for detection according to a preferred embodiment of the present invention. As shown in Fig. 1, a wafer 10 is first provided. A material layer is then formed on the wafer 10, wherein the material layer is preferably a photosensitive material layer 12, such as photosensitive polyimide, but not limited thereto. As shown in FIG. 2, the pattern of the material layer is subsequently defined. The photosensitive material layer 12 of the present embodiment performs an exposure and development process on the photosensitive material layer 12 by using a gray scale mask 14 to form a pedestal. 16, wherein the base 16 has a bottom portion 16A, a top portion 16B and a side surface 16C, and the base portion 16 has a decreasing horizontal section cross-sectional area from the bottom portion 16A to the top portion 16B. In addition, if the material layer is not a photosensitive material, it can be defined by other patterning processes. As shown in Fig. 3, a reflective film 18 is formed on the top portion 16B and the side surface 16C of the susceptor 16, i.e., the bump structure for detection of the present embodiment is formed.

The horizontal section of the pedestal 16 of the detecting bump structure of the present invention has a decreasing cross-sectional area from the bottom portion 16A to the top portion 16B, so that when the wafer 10 and the display panel are subjected to a pressing process, the back surface of the light-transmitting substrate of the display panel can be observed. The area of the top portion 16B of the pedestal 16 of the conductive bump structure changes as an index for judging the embossing process structure. In the above embodiment, the horizontal section cross-sectional area of the pedestal 16 is discontinuously decreasing. For example, the side 16C of the susceptor 16 has a stepped structure, and the number of steps, the top 16B, the bottom 16A and the side 16C. The size ratio is not limited to the examples shown in the drawings, but may be changed as appropriate. In addition, the design of the bump structure for detection of the present invention is not limited thereto, and may have other different designs.

Please refer to Figure 4. 4 is a schematic view showing a structure of a bump for detecting according to another preferred embodiment of the present invention. In order to simplify the description and compare the similarities and differences between the two embodiments, the same reference numerals are used to denote the same components in the embodiment. The same part will not be repeated. As shown in FIG. 4, the base 16 of the detecting bump structure of this embodiment also has a bottom portion 16A, a top portion 16B and a side surface 16C, and the base portion 16 has a decreasing horizontal section cross-sectional area from the bottom portion 16A to the top portion 16B. In the present embodiment, the horizontal section cross-sectional area of the susceptor 16 is continuously decreasing. In other words, the susceptor 16 has a conical structure and also functions as an index for judging the embossing process structure.

Please refer to Figures 5 to 7. 5 to 7 illustrate a method of detecting a wafer bonding state of a display panel according to a preferred embodiment of the present invention. As shown in Fig. 5, first, a light-transmitting substrate 30 is provided. The transparent substrate 30 is a thin film transistor substrate of a display panel (for example, a liquid crystal display panel), and includes at least one soldering area 30A and at least one detecting area 30B, and the internal wiring of the display panel, such as a data line or The gate line is electrically connected to the connection pad 32, and the detection area 30 is a light transmissive area.

As shown in FIG. 6, a wafer 40 is then provided, wherein the wafer 40 includes at least one conductive bump structure 42 and at least one bump structure 44 for inspection. The conductive bump structure 42 includes a pedestal 42A and a conductive film 42B, wherein the conductive film 42B is electrically connected to a circuit inside the wafer 40, and the detecting bump structure 44 is used to determine the result of the embossing process. The detecting bump structure 44 includes a pedestal 46 and a light reflecting film 48, wherein the pedestal 46 is disposed on the surface of the wafer 40, and the pedestal 46 has a bottom portion 46A, a top portion 46B and a side surface 46C, and the pedestal 46 has a bottom portion 46A to a top portion 46B. Has a decreasing horizontal section cross-sectional area. In this embodiment, the base 46 has a stepped structure, but not limited thereto. The shape of the base 46 may also be a conical structure as shown in FIG. 4, or other various types from the bottom 46A to the top 46B. The structural design of the decreasing horizontal section cross-sectional area. The reflective film 48 is disposed on the top 46B and the side 46C of the base 46. The pedestal 46 of the bump structure 44 for detection may be formed of a photosensitive material such as photosensitive polyimide, and is defined by a gray scale mask, but is not limited thereto. The reflective film 48 may be a film formed of a metal film or other material, and the pedestal 46 and the reflective film 48 for simplifying the process detecting bump structure 44 may be the same as the pedestal 42A and the conductive film 42B of the conductive bump structure 42, respectively. Materials are produced in the same process without additional processing.

As shown in FIG. 7, the conductive bump structure 42 of the wafer 40 is connected to the pad 32, and the detecting bump structure 46 corresponds to the detecting region 30B of the light-transmitting substrate 30. Then, the non-conductive colloid 50 is used to adhere the wafer 40 to the front surface of the transparent substrate 40, and a bonding process is performed on the wafer 40, so that the conductive film 42B of the conductive bump structure 42 is in contact with the connection pad 32 and is electrically connected. The connection is formed to form the display panel having the bump structure for detection of the present embodiment.

In the squeezing process, the pedestal 46 of the bump structure 44 for detection is compressed by the transparent substrate 30 to deform, and since the pedestal 46 has a decreasing horizontal cross-sectional area from the bottom 46A to the top 46B, the top 46B The area will vary with the degree of press-fitting, and the reflective film 48 on the surface of the susceptor 46 will also be squeezed to cause a similar abrasive effect on the surface to change its surface characteristics, for example, the degree of reflection will be squeezed. And change. In other words, as the depth of the press is deeper, the area of the top 46B of the base 46 will be larger, and the degree of reflection of the reflective film 48 at the top 46B of the base 46 will also change due to the pressing. Next, a detection process is performed to observe the reflective film 48 located at the top 46B of the susceptor 46 from the back side of the transparent substrate 30. Since the pressing effect of the pressing process is reflected in the area of the top portion 46B of the susceptor 46, and the reflective film 48 located at the top 46B of the susceptor 46 undergoes a change in the degree of glare after being squeezed, it can be detected in the inspection process. The area of the light-reflecting film 48 produced by the light-reflecting film 48 of the top portion 46B of the susceptor 46 of the detecting bump structure 44 as observed by an electron microscope is used to determine the area of the light-reflecting film 48 of the top portion 46B of the pedestal 46 after the pressing, thereby deducing The remaining height of the pedestal 46 is taken out, so that it can be judged whether the pressing of the conductive bump structure 42 is acceptable. If the area of the reflective film 48 of the top portion 46B of the pedestal 46 of the detecting bump structure 44 observed in the detecting process conforms to a preset standard, it means that the pressing process of the display panel is acceptable, and vice versa. If the process is unqualified, a rework process is required.

In summary, the present invention utilizes the detection bump structure having a decreasing horizontal section cross-sectional area design, and can quantify the result of the pressing process, thereby confirming whether the pressing of the conductive bump structure and the connection pad is effective, and The problem of excessive press-fitting or insufficient press-fitting is avoided, so that the yield of the press-bonding process and the reliability of the wafer bonding structure of the display panel can be effectively improved.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

10. . . Wafer

12. . . Photosensitive material layer

14. . . Gray scale mask

16. . . Pedestal

16A. . . bottom

16B. . . top

16C. . . side

18. . . Reflective film

30. . . Light transmissive substrate

30A. . . Weld zone

30B. . . Detection area

32. . . Connection pad

40. . . Wafer

42. . . Conductive bump structure

42A. . . Pedestal

42B. . . Conductive film

44. . . Detection bump structure

46. . . Pedestal

46A. . . bottom

46B. . . top

46C. . . side

48. . . Reflective film

50. . . Non-conductive colloid

1 to 3 are schematic views showing a method of fabricating a bump structure for detection according to a preferred embodiment of the present invention.

4 is a schematic view showing a structure of a bump for detecting according to another preferred embodiment of the present invention.

5 to 7 illustrate a method of detecting a wafer bonding state of a display panel according to a preferred embodiment of the present invention.

10. . . Wafer

16. . . Pedestal

16A. . . bottom

16B. . . top

16C. . . side

18. . . Reflective film

Claims (6)

A display panel having a bump structure for detecting, comprising: a transparent substrate comprising a detection area and a soldering area, wherein the soldering area is provided with at least one connection pad; and a wafer comprising a detecting bump structure And a conductive bump structure, wherein the conductive bump structure is disposed corresponding to the connection pad of the soldering region, the detecting conductive bump structure is corresponding to the detecting region of the transparent substrate, and the detecting bump structure is The method includes: a pedestal disposed on a surface of the wafer, the pedestal having a bottom portion, a top portion and a side surface, and the pedestal having a decreasing horizontal cross-sectional area from the bottom portion to the top portion; and a reflective film disposed The top surface and the side surface of the pedestal; and a non-conductive colloid for bonding the wafer to the transparent substrate; wherein the reflective film on the top of the pedestal is formed by the non-conductive colloid and the wafer Adhesively pressed against the surface of the transparent substrate without the connection pad. A display panel having a bump structure for detecting according to claim 1, wherein a horizontal section cross-sectional area of the susceptor is continuously decreasing. A display panel having a bump structure for detecting according to claim 1, wherein the horizontal section cross-sectional area of the susceptor is discontinuously decreasing. A display panel having a bump structure for detecting according to claim 1, wherein the pedestal The material includes a photosensitive material. A method for detecting a wafer bonding state of a display panel, comprising: providing a transparent substrate, comprising: a detecting area; providing a wafer, the wafer comprising a detecting bump structure, the detecting bump structure comprising: a base a base disposed on the surface of the wafer, the base having a bottom, a top and a side, and the base has a decreasing horizontal section cross-sectional area from the bottom to the top; and a reflective film disposed on the base The top portion and the side surface; the detecting bump structure of the wafer corresponds to the detecting region of the transparent substrate, and the non-conductive colloid is used to adhere the wafer to the front surface of the transparent substrate, and the wafer is bonded to the wafer Performing a pressing process to deform the base of the detecting bump structure; and performing a detecting process to observe an area of the reflective film located at the top of the base from the back side of the transparent substrate Judging the pressing effect of the pressing process. The method of detecting the wafer bonding state of the display panel according to claim 5, wherein the area of the light reflecting film located at the top of the susceptor is known by observing the degree of reflection of the reflective film.