TWI556366B - Chip-on-film package structure and flexible circuit board thereof - Google Patents

Description

Film flip chip package structure and flexible circuit carrier

The present invention relates to a package structure and a line carrier thereof, and more particularly to a film flip chip package structure and a flexible line carrier.

With the improvement of semiconductor technology, liquid crystal displays have the advantages of low power consumption, light weight, high resolution, high color saturation, long life, etc., and thus are widely used in mobile phones, notebook computers or desktop computers. LCD screens and LCD TVs and other electronic products that are closely related to life. Among them, the driver IC of the display is an indispensable component of the liquid crystal display.

In order to meet the needs of various applications of liquid crystal display device driving wafers, tape automatic bonding (TAB) packaging technology is generally used for chip packaging, which is further divided into Chip-On-Film (COF) package and tape winding. Tape Carrier Package (TCP). Generally, the process of wafer packaging by tape and tape automatic bonding is to first electrically bond the bumps on the wafer to the inner leads on the flexible substrate. Next, on the wafer and flexibility An encapsulant is formed between the substrates to protect the electrical contacts between the bumps and the inner leads.

Generally, a packaged colloid of a film flip chip package is formed on a package substrate in a potting manner to fill between the wafer and the package substrate and around the wafer. When the encapsulant is injected around the periphery of the wafer by the dispensing needle, the encapsulant 130 extends from the periphery of the wafer to the inside by the capillary phenomenon to fill the space formed between the wafer and the package substrate. The encapsulant can flow smoothly, and the uncured encapsulant has a considerable degree of fluidity. However, based on the fluidity of the encapsulant, it also flows in a direction away from the wafer, which makes the potting area of the encapsulant difficult to control, and it is difficult to meet some special design specifications.

On the other hand, since the film flip-chip package structure will be bent for subsequent applications, in accordance with some product design requirements, such as fingerprint identification sensors, the bending position is very close to the wafer, and the cured package The colloid hinders the bending of the flexible substrate, so the coating range of the encapsulant tends to be gradually reduced. However, based on the fluidity of the encapsulant, the control of the potting area of the encapsulant is not easy, so that the coating range cannot be effectively reduced, and it is difficult to meet the requirements of product design.

The present invention provides a thin film flip-chip package structure and a flexible wiring carrier thereof, which can conform to the design trend of reducing the coating range of the encapsulant, and can make the coating range fall within the tolerance value.

The invention provides a thin film flip chip package structure comprising a flexible circuit carrier, a wafer and an encapsulant. The flexible circuit carrier includes a flexible substrate, a patterned wiring layer, and a stop material. The flexible substrate has a surface and a wafer bond region and trench on the surface, and the trench surrounds the wafer bond region. The patterned wiring layer is disposed on the aforementioned surface. The stop material is filled in the trench. The wafer is disposed on the flexible substrate and located in the wafer bonding region and electrically connected to the patterned wiring layer. The encapsulant is formed between the wafer and the flexible substrate and around the wafer, wherein the encapsulant is in contact with the stopper material, and the side edges of the encapsulant are on the stopper material.

The present invention provides a flexible wiring carrier that includes a flexible substrate, a patterned wiring layer, and a stop material. The flexible substrate has a surface and a wafer bond region and trench on the surface, and the trench surrounds the wafer bond region. The patterned wiring layer is disposed on the aforementioned surface. The stop material is filled in the trench.

In an embodiment of the invention, the trench has an inner edge and an outer edge. The side edges of the encapsulant are located between the inner and outer edges.

In an embodiment of the invention, the shortest distance between the outer edge of the trench and the side edge of the adjacent wafer is between 100 microns and 800 microns.

In an embodiment of the invention, the trench has a width between 10 microns and 50 microns.

In an embodiment of the invention, the stopper material exposed to the upper surface of the trench is coplanar with the surface of the flexible substrate.

In an embodiment of the invention, the flexible circuit carrier further includes a solder resist layer. The solder resist layer is disposed on the flexible substrate to partially cover the patterned circuit layer and A windowing zone is defined in which the wafer land and the trench are located in the windowing zone.

In an embodiment of the invention, the material of the stopper material is the same as the material of the solder resist layer.

In an embodiment of the invention, the patterned circuit layer includes a plurality of pins. Each pin includes an inner pin and a pin connected to the aforementioned inner pin. The inner lead is electrically connected to the wafer by a stopper material extending into the wafer bonding region.

In an embodiment of the invention, the stopper material includes a solder resist ink, a dry film solder mask ink (DFSM) or a liquid photosensitive solder resist ink.

In an embodiment of the invention, the shortest distance between the outer edge of the trench and the side edge of the adjacent wafer bonding region is between 100 microns and 800 microns.

Based on the above, the film flip chip package structure of the present invention comprises a flexible circuit carrier, and the flexible substrate of the flexible circuit carrier has a trench, wherein the trench surrounds the wafer bonding region on the flexible substrate. In addition, it is filled with a stopper material. After the wafer is electrically connected to the patterned circuit layer, an encapsulant is formed between the wafer and the flexible substrate and around the wafer to protect the electrical contact between the wafer and the patterned wiring layer. Based on the fluidity of the encapsulant, when the encapsulation is wound around the periphery of the wafer to inject the encapsulant into the space formed between the active surface of the wafer and the surface of the flexible substrate, the encapsulant will also face away from the wafer. The direction (ie the direction of the ditch) flows.

Since the flow rate of the encapsulant of the present invention on the stopper material is smaller than the flow speed of the encapsulant on the flexible substrate, that is, the encapsulant and the stopper The surface adhesion between the materials is greater than the surface adhesion between the encapsulant and the flexible substrate, so that when the encapsulant flows to the trench and contacts the stopper material, the encapsulant is gradually restricted by the stopper material. Stop the flow so that its side edges stop on the stop material. Here, the present invention can define the upper limit of the tolerance of the coating range of the encapsulant by the outer edge of the trench, and the inner edge of the trench defines the lower tolerance limit of the coating range of the encapsulant, in other words, by providing a ditch. The flexible substrate is filled with a stopper material in the trench, so that the coating range of the encapsulant can fall within the expected size and the specified tolerance value without being flexible beyond the outer edge of the trench. Other areas of the substrate can effectively reduce the coating area of the encapsulant to facilitate the bending of the film flip chip structure adjacent to the wafer in subsequent applications, and meet the application requirements of the product.

The above described features and advantages of the invention will be apparent from the following description.

100‧‧‧film flip chip package structure

110‧‧‧Flexible line carrier

111‧‧‧Flexible substrate

111a‧‧‧ surface

111b‧‧‧ wafer junction area

111c‧‧‧ Ditch

112‧‧‧ patterned circuit layer

112a‧‧‧ pin

112b‧‧‧ inner pin

112c‧‧‧External pin

113‧‧‧stop material

113a‧‧‧ upper surface

114‧‧‧ solder mask

114a‧‧‧window area

120‧‧‧ wafer

121‧‧‧Active surface

122‧‧‧Bumps

130‧‧‧Package colloid

D‧‧‧Distance

G‧‧‧Short distance

OE‧‧‧ outer edge

IE‧‧‧ inner edge

W‧‧‧Width

1 is a top plan view of a thin film flip chip package structure in accordance with an embodiment of the present invention.

2 is a cross-sectional view of the thin film flip chip package structure of FIG. 1 taken along line A-A.

1 is a top plan view of a thin film flip chip package structure in accordance with an embodiment of the present invention. 2 is a cross-sectional view of the thin film flip chip package structure of FIG. 1 taken along line A-A, The encapsulant 130 is not shown in FIG. 1 for clarity and convenience of description. Referring to FIG. 1 and FIG. 2 , in the embodiment, the thin film flip chip package structure 100 includes a flexible circuit carrier 110 , a wafer 120 , and an encapsulant 130 , wherein the flexible circuit carrier 110 includes a flexible substrate 111. Patterning the wiring layer 112 and the stopper material 113.

The flexible substrate 111 has a surface 111a and a wafer bonding region 111b and a trench 111c on the surface 111a, and the trench 111c surrounds the wafer bonding region 111b. Generally, the material of the flexible substrate 111 may include polyimide (PI), polyethylene terephthalate (PET), polyethersulfone (PES), and carbonate ( Polycarbonate, PC) or other suitable flexible material, and the trench 111c is formed on the flexible substrate 111, for example, by photolithographic etching, and has a width W of between 10 micrometers and 15 micrometers.

The patterned wiring layer 112 is disposed on the surface 111a, wherein the patterned wiring layer 112 may include a plurality of pins 112a, wherein the materials of the pins 112a are, for example, copper, silver, tin, aluminum, nickel, gold or other suitable conductive metal. On the other hand, the stopper material 113 is filled in the trench 111c, and the wafer 120 is disposed on the flexible substrate 111 and located in the wafer bonding region 111b, and is electrically connected to the patterned wiring layer 112. Here, the wafer 120 is, for example, a fingerprint recognition sensing wafer, but the present invention is not limited thereto. In detail, each pin 112a includes an inner pin 112b and a pin 112c other than the inner pin 112b. The wafer 120 has a plurality of bumps 122 on its active surface 121 (Fig. 2 schematically shows two ), wherein the active surface 121 faces the surface 111a. In the present embodiment, the inner leads 112b are extended by the blocking material 113 into the wafer bonding region 111b, and the inner leads 112b and the corresponding bumps 122 are, for example, by hot pressing. The eutectic bonding is performed to achieve an electrical connection between the patterned wiring layer 112 and the wafer 120.

In the present embodiment, the flexible circuit carrier 110 further includes a solder resist layer 114. The solder resist layer 114 is disposed on the flexible substrate 111 to partially cover the patterned wiring layer 112 and defines a window opening region 114a, wherein the wafer bonding region 111b and the trench 111c are located in the window opening region 114a, and the window opening region 114a The inner pin 112b is exposed. Specifically, the solder resist layer 114 can be used to protect the leads 112a, that is, under the coverage of the solder resist layer 114, to prevent the pins 112a from being short-circuited or broken due to scratches or contamination. In addition, the material of the stopper material 113 is made of an insulating material, and the solder resist layer 114 may be made of the same material, for example, solder resist ink, dry film solder resist ink or liquid photosensitive solder resist ink, but the invention is not limited thereto. . In other embodiments, the stopper material 113 and the solder resist layer 114 may also be made of different materials.

As shown in FIG. 2, the trench 111c has an inner edge IE and an outer edge OE, wherein the shortest distance G between the outer edge OE of the trench 111c and the side edge of the adjacent wafer 120 is between about 100 micrometers and 800 micrometers. And preferably between 100 microns and 300 microns. Here, the wafer bonding region 111b is defined, for example, by the orthographic projection area of the wafer 120 on the flexible substrate 111, and the shortest distance between the outer edge OE of the trench 111c and the side edge of the adjacent wafer bonding region 111b is substantially The upper surface is coincident with the aforementioned shortest distance G, that is, between 100 micrometers and 800 micrometers, and preferably between 100 micrometers and 300 micrometers. On the other hand, the upper surface 113a of the stopper material 113 exposed to the trench 111c is coplanar with the surface 111a of the flexible substrate 111, so that the bending of the inner lead 112b above the stopper material 113 can be avoided to maintain Pin The planar uniformity of 112a, which in turn reduces the probability of pin 112a breaking during the process.

The encapsulant 130 is formed between the active surface 121 of the wafer 120 and the surface 111a of the flexible substrate 111, and covers the periphery of the wafer 120 to protect between the inner leads 112b and the corresponding bumps 122. Electrical contacts. Generally, the encapsulant 130 is an underfill material, such as an epoxy resin or other polymer material, and the encapsulant 130 can smoothly fill the wafer 120 and the flexible substrate 111. In a small space, the film flip-chip package structure 100 is usually by means of dispensing, and the periphery of the wafer 120 is wound around the wafer 120 to dispense the encapsulant 130, wherein the encapsulant 130 is caused by the capillary phenomenon from the wafer 120. The periphery extends to the inside to fill the space formed between the active surface 121 of the wafer 120 and the surface 111a of the flexible substrate 111. To enable the encapsulant 130 to flow smoothly, the uncured encapsulant 130 must have a considerable degree. Mobility. However, based on the fluidity of the encapsulant 130, it also flows in a direction away from the wafer 120, that is, in the direction toward the trench 111c, and is in contact with the stopper material 113 in the trench 111c.

In the present embodiment, the flow velocity of the encapsulant 130 on the upper surface 113a of the stopper material 113 is smaller than the flow velocity of the encapsulant 130 on the surface 111a of the flexible substrate 111, whether in a normal temperature or high temperature environment. That is, the surface adhesion between the encapsulant 130 and the stopper material 113 is greater than the surface adhesion between the encapsulant 130 and the flexible substrate 111, so that the uncured encapsulant 130 flows to the trench 111c. At this time, it can be blocked on the stopper material 113.

In short, the formation of the encapsulant 130 on the flexible substrate 111 has been During the process, the encapsulant 130 flowing toward the trench 111c can be restricted by the stopper material 113 without overflowing to other regions on the flexible substrate 111 outside the trench 111c. Therefore, the side edge of the encapsulated encapsulant 130 can be located on the stopper material 113 and located between the inner edge IE and the outer edge OE of the trench 111c to facilitate subsequent processes. That is, the upper limit of the tolerance value of the coating range of the encapsulant 130 can be defined by the outer edge OE of the trench 111c, and the inner edge IE of the trench 111c defines the tolerance of the coating range of the encapsulant 130. The lower limit of the value, so after the periphery of the wafer 120 is wound with the dispensing needle to inject the encapsulant 130, the side edge of the encapsulant 130 will at least exceed the inner edge IE, and the principle of not exceeding the outer edge OE.

On the other hand, when the encapsulant 130 flows beyond the inner edge IE, the surface adhesion between the encapsulant 130 and the stopper material 113 is greater than the surface adhesion between the encapsulant 130 and the flexible substrate 111, The encapsulant 130 is gradually restricted from flowing by the stopper material 113 so that its side edge terminates on the stopper material 113. At this time, the distance D between the side edge of the encapsulant 130 and the inner edge IE is, for example, 6 μm or less, and preferably less than 3 μm.

For example, the thin film flip chip package structure 100 can be bent for subsequent applications, such as a fingerprint sensor or the like, wherein the position of the bend of the film flip chip package structure 100 may be relatively close to the wafer 120. However, the encapsulated colloid 130 after curing may hinder the bending of the flexible substrate 110, so that the coating range of the encapsulant 130 is correspondingly reduced in response to the demand for miniaturization of the product. Since the film flip chip package structure 100 of the present invention can control the coating range of the encapsulant 130 through the trench 111c and the stopper material 113, and the coating range of the encapsulant 130 falls within the tolerance value. Between the limit and the lower limit, the encapsulated encapsulant 130 after curing can be effectively reduced to meet the application requirements of the product.

In summary, the thin film flip chip package structure of the present invention comprises a flexible circuit carrier, and the flexible substrate of the flexible circuit carrier has a trench, wherein the trench surrounds the wafer on the flexible substrate Outside the zone, it is filled with a stop material. After the wafer is electrically connected to the patterned circuit layer, an encapsulant is formed between the wafer and the flexible substrate and around the wafer to protect the electrical contact between the wafer and the patterned wiring layer. Based on the fluidity of the encapsulant, when the encapsulation is wound around the periphery of the wafer to inject the encapsulant into the space formed between the active surface of the wafer and the surface of the flexible substrate, the encapsulant will also face away from the wafer. The direction (ie the direction of the ditch) flows.

Since the flow rate of the encapsulant of the present invention on the stopper material is smaller than the flow speed of the encapsulant on the flexible substrate, that is, the surface adhesion between the encapsulant and the stopper is greater than that of the encapsulant and the flexible The surface adhesion between the substrates, so that when the encapsulant flows to the trench and contacts the stopper material, the encapsulant is restricted by the stopper material and gradually stops flowing so that the side edges stop at the stopper material. on. Here, the present invention can define the upper limit of the tolerance of the coating range of the encapsulant by the outer edge of the trench, and the inner edge of the trench defines the lower tolerance limit of the coating range of the encapsulant, in other words, by providing a ditch. The flexible substrate is filled with a stopper material in the trench, so that the coating range of the encapsulant can fall within the expected size and the specified tolerance value without being flexible beyond the outer edge of the trench. Other areas of the substrate can effectively reduce the coating area of the encapsulant to facilitate In the continued application, the film flip-chip package structure is bent at the adjacent wafer and meets the application requirements of the product.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧film flip chip package structure

110‧‧‧Flexible line carrier

111‧‧‧Flexible substrate

111a‧‧‧ surface

111c‧‧‧ Ditch

112a‧‧‧ pin

112b‧‧‧ inner pin

112c‧‧‧External pin

113‧‧‧stop material

113a‧‧‧ upper surface

114‧‧‧ solder mask

114a‧‧‧window area

120‧‧‧ wafer

121‧‧‧Active surface

122‧‧‧Bumps

130‧‧‧Package colloid

D‧‧‧Distance

G‧‧‧Short distance

OE‧‧‧ outer edge

IE‧‧‧ inner edge

W‧‧‧Width

Claims (17)

A film flip chip package structure comprising: a flexible circuit carrier, comprising: a flexible substrate having a surface and a wafer bonding region and a trench on the surface, and the trench is surrounded by the wafer bonding a patterned circuit layer disposed on the surface; and a stopper material filled in the trench; a wafer disposed on the flexible substrate and located in the wafer bonding region, and The patterned circuit layer is electrically connected; and an encapsulant is formed between the wafer and the flexible substrate and around the wafer, wherein the encapsulant is in contact with the blocking material, and the side of the encapsulant The edge is on the stop material. The film flip-chip package structure of claim 1, wherein the trench has an inner edge and an outer edge, and the side edge of the encapsulant is located between the inner edge and the outer edge. The thin film flip chip package structure of claim 2, wherein a shortest distance between the outer edge of the trench and a side edge of the adjacent wafer is between 100 micrometers and 800 micrometers. The thin film flip chip package structure of claim 3, wherein the trench has a width of between 10 micrometers and 50 micrometers. The film flip chip package structure according to claim 1, wherein the stopper material is exposed to an upper surface of the trench and the surface of the flexible substrate is flat. The thin film flip chip package structure of claim 1, wherein the flexible circuit carrier further comprises: a solder resist layer disposed on the flexible substrate, the solder resist layer partially covering the pattern The circuit layer is defined and defines an open window region, wherein the wafer bonding region and the trench are located in the window opening region. The film flip chip package structure according to claim 6, wherein the material of the stopper material is the same as the material of the solder resist layer. The thin film flip chip package structure of claim 1, wherein the patterned circuit layer comprises a plurality of pins, each of the pins comprising an inner pin and an outer pin connecting the inner pin, The inner lead is electrically connected to the wafer by the stopper material extending into the wafer bonding region. The film flip chip package structure according to claim 1, wherein the stopper material comprises a solder resist ink, a dry film solder resist ink or a liquid photosensitive solder resist ink. A flexible circuit carrier comprising: a flexible substrate having a surface and a die bond region and a trench on the surface, the trench surrounding the die bond region; a patterned circuit layer Disposed on the surface; and a stopper material filled in the trench. The flexible circuit carrier of claim 10, wherein the upper surface of the barrier material exposed to the trench is coplanar with the surface of the flexible substrate. The flexible circuit carrier of claim 10, further comprising: a solder resist layer disposed on the flexible substrate, the solder resist layer partially covering the patterned circuit layer and defining a a window opening region, wherein the wafer bonding region and the trench are located in the window opening region. The flexible circuit carrier according to claim 12, wherein the material of the stopper material is the same as the material of the solder resist layer. The flexible circuit carrier of claim 10, wherein the patterned circuit layer comprises a plurality of pins, each of the pins comprising an inner pin and an outer pin connecting the inner pin. The inner lead passes through the stop material to extend into the wafer bond area. The flexible circuit carrier as claimed in claim 10, wherein the blocking material comprises a solder resist ink, a dry film solder resist ink or a liquid photosensitive solder resist ink. The flexible circuit carrier of claim 10, wherein a shortest distance between an outer edge of the trench and a side edge of the adjacent wafer bonding region is between 100 micrometers and 800 micrometers. . The flexible circuit carrier of claim 16, wherein the trench has a width between 10 microns and 50 microns.