Flexible circuit board, manufacturing method therefor, and semiconductor package and electronic device which comprise flexible circuit board

Abstract

Provided are: a flexible circuit board in which a line width change point of an extension wire connected to a pad is adjusted to a position where stress can be distributed; a manufacturing method therefor; and a semiconductor package and an electronic device which comprise the flexible circuit board. The flexible circuit board comprises: a base layer; a wiring layer formed on the base layer; and a pad unit electrically connected to the wiring layer, wherein the pad unit includes a first pad, a second pad and an extension wiring that extends from the wiring layer and is connected to the first pad through the second pad, and a line width change starting point of the extension wiring is not located on the extension line of a first side of the second pad adjacent to the first pad.

Description

Flexible circuit board and method for manufacturing the same, and semiconductor package and electronic device including the flexible circuit board

[0001] The present invention relates to a flexible circuit board including a pad connected to a circuit, a method for manufacturing the same, and a semiconductor package and electronic device including the flexible circuit board.

[0002] A flexible circuit board may include test pads for electrically testing the circuit. A plurality of test pads may be formed corresponding to the number of circuit terminals within the flexible circuit board. Each test pad may be connected to the end of an extension wire extending from each circuit terminal.

[0003] FIG. 1 is an exemplary diagram illustrating a plurality of test pads and a plurality of extension wires within a flexible circuit board. Referring to FIG. 1, a first test pad (310) is connected to the end of a first extension wire (320), and a second test pad (330) is connected to the end of a second extension wire (340). The first test pad (310) and the second test pad (330) are formed wider than the first extension wire (320) and the second extension wire (340) for the convenience of circuit inspection. In addition, in order to efficiently arrange a plurality of test pads in a limited space, the first test pad (310) is arranged behind the second test pad (330). In this case, the first extension wire (320) passes through the second test pad (330) and is connected to the first test pad (310).

[0004] The flexible circuit board is flexible and can be bent. When the flexible circuit board is bent in this manner, stress may be concentrated in a portion of the first extension wire (320) adjacent to the second test pad (330) due to a thickness difference between the first extension wire (320) and the second test pad (330). In particular, cracks may frequently occur in a portion (350) located on the same line as one side (360) of the second test pad (330).

[0005] The technical problem to be solved by the present invention is to provide a flexible circuit board having an increased line width of an extension wiring adjacent to a pad, a method for manufacturing the same, and a semiconductor package and electronic device including the flexible circuit board.

[0006] The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0007] One aspect of a flexible circuit board of the present invention for achieving the above technical task includes a substrate layer; a wiring layer formed on the substrate layer; and a pad portion electrically connected to the wiring layer, wherein the pad portion includes a first pad; a second pad; and an extension wiring extending from the wiring layer and passing through the second pad and connected to the first pad, wherein a line width change starting point of the extension wiring is not located on an extension line of a first side of the second pad adjacent to the first pad.

[0008] One aspect of a semiconductor package of the present invention for achieving the above technical task includes a flexible circuit board; and a semiconductor chip mounted on the flexible circuit board and electrically connected to a wiring layer in the flexible circuit board through a bump, wherein the flexible circuit board includes a substrate layer; a wiring layer formed on the substrate layer; and a pad portion electrically connected to the wiring layer, wherein the pad portion includes a first pad; a second pad; and an extension wiring extending from the wiring layer, passing through the second pad and connected to the first pad, wherein a line width change starting point of the extension wiring is not located on an extension line of a first side of the second pad adjacent to the first pad.

[0009] One aspect of the electronic device of the present invention for achieving the above technical task includes a semiconductor package including a flexible circuit board and a semiconductor chip; and an external device electrically connected to the semiconductor chip through the flexible circuit board, wherein the flexible circuit board includes a substrate layer; a wiring layer formed on the substrate layer; and a pad portion electrically connected to the wiring layer, wherein the pad portion includes a first pad; a second pad; and an extension wiring extending from the wiring layer, passing through the second pad and connected to the first pad, wherein a line width change starting point of the extension wiring is not located on an extension line of a first side of the second pad adjacent to the first pad.

[0010] One aspect of a method for manufacturing a flexible circuit board of the present invention for achieving the above technical task includes the steps of forming a wiring layer on a substrate layer; and forming a pad portion electrically connected to the wiring layer on the substrate layer, wherein the pad portion includes a first pad; a second pad; and an extension wiring extending from the wiring layer and passing through the second pad and connected to the first pad, wherein a line width change starting point of the extension wiring is not located on an extension line of a first side of the second pad adjacent to the first pad.

[0011] Specific details of other embodiments are included in the detailed description and drawings.

[0012] According to the present invention, the following effects can be obtained by increasing the line width of the extension wiring adjacent to the pad.

[0013] First, it can reduce the frequency of crack occurrence in the extension wiring adjacent to the pad.

[0014] Second, the durability and quality of the product can be improved by improving the stress applied to the points where cracks frequently occur.

[0015] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

[0016] Figure 1 is an exemplary diagram illustrating multiple test pads and multiple extension wires within a flexible circuit board.

[0017] FIG. 2 is a first exemplary diagram illustrating a flexible circuit board according to some embodiments of the present invention.

[0018] FIG. 3 is an exemplary diagram illustrating a wiring layer constituting a flexible circuit board according to some embodiments of the present invention.

[0019] FIG. 4 is a second exemplary diagram illustrating a flexible circuit board according to some embodiments of the present invention.

[0020] FIG. 5 is a first exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0021] FIG. 6 is a second exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0022] FIG. 7 is a third exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0023] FIG. 8 is a fourth exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0024] FIG. 9 is a fifth exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0025] FIG. 10 is a sixth exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0026] FIG. 11 is a seventh exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0027] FIG. 12 is an eighth exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0028] FIG. 13 is a ninth exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0029] FIG. 14 is a tenth exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0030] FIG. 15 is an eleventh exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0031] FIG. 16 is a twelfth exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0032] FIG. 17 is a third exemplary diagram illustrating a flexible circuit board according to some embodiments of the present invention.

[0033] FIG. 18 is a fourth exemplary diagram illustrating a flexible circuit board according to some embodiments of the present invention.

[0034] FIG. 19 is a fifth exemplary diagram illustrating a flexible circuit board according to some embodiments of the present invention.

[0035] FIG. 20 is an exemplary diagram illustrating a semiconductor package including a flexible circuit board according to some embodiments of the present invention.

[0036] FIG. 21 is an exemplary diagram illustrating an electronic device including a flexible circuit board according to some embodiments of the present invention.

[0037] FIG. 22 is a flowchart illustrating a method for manufacturing a flexible circuit board according to one embodiment of the present invention.

[0038] FIG. 23 is a flowchart illustrating a method for manufacturing a flexible circuit board according to another embodiment of the present invention.

[0039] FIG. 24 is a sixth exemplary diagram illustrating a flexible circuit board according to some embodiments of the present invention.

[0040] FIG. 25 is a first exemplary diagram illustrating a via pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0041] FIG. 26 is a second exemplary diagram illustrating a via pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. Identical components in the drawings will be designated by the same reference numerals, and redundant descriptions thereof will be omitted.

[0043] There is a relative difference in flexural strength between the portion of the wiring layer and the space portion within the flexible circuit board, and the difference is particularly large at the boundary between the test pad and the space, which may result in concentrated physical stress. Accordingly, there is a problem that cracks frequently occur in the portion (350) of the first extension wiring (320) corresponding to the imaginary extension line of the space boundary due to the relatively large physical stress.

[0044] In the present invention, the line width of the first extension wiring (320) adjacent to the second test pad (330) can be increased. The line width of the first extension wiring (320) can be formed to be wider than the line width of the circuit in the flexible circuit board. The line width change point of the first extension wiring (320) may not correspond to an extension line of the side (360) of the second test pad (330). The present invention will be described in detail below.

[0045] FIG. 2 is a first exemplary diagram illustrating a flexible circuit board according to some embodiments of the present invention. Referring to FIG. 2, the flexible circuit board (100) may be configured to include a substrate layer (110), a first wiring layer (120), a first protective layer (130), and a first test pad portion (140).

[0046] The present invention can be applied to a flexible circuit board (100). For example, the flexible circuit board (100) can be provided as a chip-on-film (COF). However, the present invention is not limited thereto, and it goes without saying that the present invention can be applied to other circuit boards having properties such as rigidity and rigid-flexibility.

[0047] A first direction (D1) and a second direction (D2) can form a two-dimensional plane. The first direction (D1) may be an X-axis direction, and the second direction (D2) may be a Y-axis direction. The first direction (D1) may be a left-right direction, and the second direction (D2) may be a front-back direction. Alternatively, the first direction (D1) may be a front-back direction, and the second direction (D2) may be a left-right direction. A third direction (D3) may form a three-dimensional solid with the first direction (D1) and the second direction (D2). The third direction (D3) is a direction perpendicular to a plane formed by the first direction (D1) and the second direction (D2). The third direction (D3) may be a Z-axis direction. The third direction (D3) may be an up-down direction.

[0048] The substrate layer (110) may be formed as a base film having a certain thickness. The substrate layer (110) may be formed as a flexible film, but is not limited thereto and may also be formed as a rigid flexible film or a rigid film.

[0049] The substrate layer (110) may be formed of an insulating resin. For example, the substrate layer (110) may include at least one polymer material selected from polyimide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate, epoxy, and glass fiber. The polymer material forming the substrate layer (110) is not limited thereto, and any material may be used as long as it enables insulating performance within the flexible circuit board (100).

[0050] Although not shown in FIG. 2, a seed layer may be provided to increase bonding between the substrate layer (110) and the first wiring layer (120). The seed layer may be provided as a conductive layer in the form of a thin film on the substrate layer (110). For example, the seed layer may be formed of any one metal selected from conductive metals such as nickel (Ni), chromium (Cr), copper (Cu), gold (Au), aluminum (Al), and palladium (Pd), or an alloy composed of multiple metals. The seed layer may be formed on the substrate layer (110) by a physical method such as deposition, adhesion, or plating, or by a chemical method.

[0051] An underlayer may be further provided on the seed layer. The underlayer may be formed of the same metal as the seed layer, but may also be formed of a different metal. The underlayer may have a thickness equivalent to that of the seed layer, but is not limited thereto, and may be formed to be thicker or thinner than the seed layer. It is also possible for only the underlayer to be formed on the substrate layer (110) without the seed layer being formed.

[0052] The first wiring layer (120) may be formed on the substrate layer (110). The first wiring layer (120) may be formed of an electrically conductive material. For example, the first wiring layer (120) may be formed of any one metal selected from conductive metals such as nickel (Ni), chromium (Cr), copper (Cu), gold (Au), silver (Ag), platinum (Pt), aluminum (Al), palladium (Pd), titanium (Ti), and tin (Sn), or an alloy formed of multiple metals.

[0053] The first wiring layer (120) can be formed on the substrate layer (110) using etching. In this case, a metal layer is formed on the substrate layer (110) and wiring is formed through photo etching, thereby providing the first wiring layer (120) as a conductive layer on the substrate layer (110).

[0054] The first wiring layer (120) may be formed on the substrate layer (110) using plating. In this case, after forming a metal layer on the substrate layer (110), wiring may be formed through an additive process, printing, coating, etc., so that the first wiring layer (120) may be provided as a conductive layer on the substrate layer (110). The additive process refers to a method of forming a plating resist pattern on a metal layer and then forming wiring through a plating method. Printing refers to a method of printing a conductive paste on the substrate layer (110). Coating refers to a method of transferring a conductive paste onto the substrate layer (110). When plating is used, the first wiring layer (120) may be formed on the substrate layer (110) using either an electrolytic plating method or an electroless plating method.

[0055] FIG. 3 is an exemplary diagram illustrating a wiring layer constituting a flexible circuit board according to some embodiments of the present invention. Referring to FIG. 3, the first wiring layer (120) may include an electrode pattern (210), an inner lead (220), and an outer lead (230).

[0056] The electrode pattern (210) may be formed within the wiring area (WA). The inner lead (220) may be formed within the inner lead area (ILA). The outer lead (230) may be formed within the outer lead area (OLA). The electrode pattern (210) may connect the inner lead (220) and the outer lead (230). The inner lead (220) and the outer lead (230) may be provided as terminal portions of the electrode pattern (210). The electrode pattern (210), the inner lead (220), and the outer lead (230) may each be formed as a plurality of wiring lines.

[0057] The inner lead area (ILA) may be provided on one side of the substrate layer (110), and the outer lead area (OLA) may be provided on the other side of the substrate layer (110). The outer lead area (OLA) may be provided on one side of the inner lead area (ILA). However, the present invention is not limited thereto, and the outer lead area (OLA) may also be provided on both sides of the inner lead area (ILA).

[0058] This is explained again with reference to Figure 2.

[0059] A first protective layer (130) may be formed on the first wiring layer (120) to protect the first wiring layer (120). The first protective layer (130) may be formed as an insulating resin layer including a solder resist. The first protective layer (130) may be formed using various methods such as printing, bonding, coating, and photolithography. In the case of printing or coating, the first protective layer (130) may be formed by printing or coating a liquid solder resist. In the case of bonding, the first protective layer (130) may be formed by bonding a coverlay film using a lamination method.

[0060] The first protective layer (130) may cover both the upper surface and the side surface of the first wiring layer (120). Alternatively, the first protective layer (130) may cover only the upper surface of the first wiring layer (120). The first protective layer (130) may not cover the inner lead (220) and the outer lead (230). The inner lead (220) and the outer lead (230) may be exposed to the outside.

[0061] The first protective layer (130) may not cover the first test pad portion (140). However, the present invention is not limited thereto, and the first protective layer (130) may also cover the first test pad portion (140). The first protective layer (130) may cover a portion of the first test pad portion (140), and may also cover the entire first test pad portion (140).

[0062] The first test pad portion (140) may be provided to electrically test the first wiring layer (120). The first test pad portion (140) may be used to determine whether the first wiring layer (120) is defective by testing for open or short circuits. The first test pad portion (140) may be removed from the flexible circuit board (100) after the test for the first wiring layer (120) is completed. However, the present invention is not limited thereto, and the first test pad portion (140) may remain on the flexible circuit board (100) even after the test for the first wiring layer (120) is completed.

[0063] The first test pad portion (140) may be connected to the end of an extension wire extending from the terminal portion. Referring to FIG. 3, the first test pad portion (140) may be formed within a dummy area (DA). The first test pad portion (140) may be electrically connected to an extension wire extending from the inner lead (220). Alternatively, the first test pad portion (140) may be electrically connected to an extension wire extending from the outer lead (230). However, the present invention is not limited thereto, and the first test pad portion (140) may also be electrically connected to an extension wire extending from the electrode pattern (210).

[0064] The first test pad portion (140) may be formed on the same surface as the first wiring layer (120). However, the present invention is not limited thereto, and the first test pad portion (140) may also be formed on a different surface from the first wiring layer (120). Referring to FIG. 4, in such a case, the first test pad portion (140) may be electrically connected to the first wiring layer (120) through a first via (150) penetrating the substrate layer (110). FIG. 4 is a second exemplary diagram illustrating a flexible circuit board according to some embodiments of the present invention.

[0065] The first test pad section (140) may include a plurality of test pads. The number of test pads may correspond to the number of outer leads (230). Alternatively, the number of test pads may correspond to the number of inner leads (220). Alternatively, the number of test pads may correspond to the sum of the inner leads (220) and the outer leads (230).

[0066] For example, the first test pad section (140) may include two test pads. The first test pad section (140) may include a first test pad (310) and a second test pad (330). The first test pad (310) may be electrically connected to the first extension wire (320), and the second test pad (330) may be electrically connected to the second extension wire (340). Both the first extension wire (320) and the second extension wire (340) may be electrically connected to the outer lead (230). Alternatively, both the first extension wire (320) and the second extension wire (340) may be electrically connected to the inner lead (220). Alternatively, the first extension wire (320) may be electrically connected to the inner lead (220), and the second extension wire (340) may be electrically connected to the outer lead (230).

[0067] In the present invention, the starting point of the line width change of the first extension wiring (320) can be adjusted to a point where stress distribution is possible. The starting point of the line width change of the first extension wiring (320) may not be located on the same line as the first side of the second test pad (330) adjacent to the first test pad (310). In other words, the starting point of the line width change of the first extension wiring (320) may not be located on an extension line of the first side of the second test pad (330).

[0068] If the starting point of the line width change of the first extension wiring (320) is located on the extension line of the first side of the second test pad (330), when stress is applied to the starting point of the line width change, the stress may be concentrated because there is no lead or test pad around it. In addition, the part where the starting point of the line width change is located may be vulnerable to cracks due to the same line width as the circuit line width.

[0069] On the other hand, if the starting point of the line width change of the first extension wiring (320) is not located on the extension line of the first side of the second test pad (330), crack resistance can be improved through stress distribution. In particular, if the starting point of the line width change of the first extension wiring (320) is located inside the extension line of the first side of the second test pad (330), the part where the starting point of the line width change is located can reduce the frequency of crack occurrence by having a line width that is wider than the circuit line width.

[0070] Referring to FIG. 5, if a point located on an extension line of the first side (420) of the second test pad (330) is defined as a reference point (RP), the line width change starting point (430) of the first extension wiring (320) may be located inside the reference point (RP). Here, being located inside the reference point (RP) means that it is further away from the first test pad (310) than the reference point (RP). The first extension wiring (320) may extend from the terminal with a constant width and then expand in width from the line width change starting point (430). The line width (LW1) of the first extension wiring (320) at the reference point (RP) may be formed to be larger than the general wiring width (LW2) of the first extension wiring (320). The first side edge (410) of the first test pad (310) refers to a side adjacent to the second test pad (330), and the first side edge (420) of the second test pad (330) refers to a side adjacent to the first test pad (310). Fig. 5 is a first exemplary diagram for explaining a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0071] The line width change section (INT) of the first extension wire (320) can be divided based on the line width change starting point (430) and the line width change ending point (440). Referring to FIG. 5, the line width change starting point (430) and the line width change ending point (440) can be connected by a curve. The curve connecting the line width change starting point (430) and the line width change ending point (440) can have a concave shape in the direction where the second test pad (330) is located. Although not shown in the drawing, the curve connecting the line width change starting point (430) and the line width change ending point (440) can also have a convex shape in the direction where the second test pad (330) is located.

[0072] However, the invention is not limited thereto, and referring to Fig. 6, the line width change starting point (430) and the line width change ending point (440) may also be connected in a straight line. Fig. 6 is a second exemplary diagram illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0073] The line width change starting point (430) and the line width change ending point (440) may be connected by a single straight line, but may also be connected by multiple straight lines. For example, the multiple straight lines may be two straight lines, such as a first straight line and a second straight line.

[0074] When the line width change starting point (430) and the line width change ending point (440) are connected by multiple straight lines, the line width change section (INT) of the first extension wiring (320) can add at least one line width change midpoint as its reference point in addition to the line width change starting point (430) and the line width change ending point (440). When the line width change section (INT) is connected by a first straight line and a second straight line, the first straight line can connect the line width change starting point (430) and the line width change midpoint (450), and the second straight line can connect the line width change midpoint (450) and the line width change ending point (440).

[0075] Referring to FIG. 7, the line width change midpoint (450) may be located on an extension of the first side edge (420) of the second test pad (330). In this case, the line width (LW1) of the first extension wiring (320) located on the extension of the first side edge (420) of the second test pad (330) may be wider than the general wiring width (LW2) of the first extension wiring (320). The line width change midpoint (450) may not be located on an extension of the first side edge (420) of the second test pad (330). Referring to FIG. 8, the line width change midpoint (450) may be located inside the reference point (RP). Alternatively, referring to FIG. 9, the line width change midpoint (450) may be located outside the reference point (RP). Even in this case, the line width (LW1) of the first extension wiring (320) positioned on the extension line of the first side (420) of the second test pad (330) may be wider than the general wiring width (LW2) of the first extension wiring (320). Fig. 7 is a third exemplary diagram for explaining a test pad portion constituting a flexible circuit board according to some embodiments of the present invention. Fig. 8 is a fourth exemplary diagram for explaining a test pad portion constituting a flexible circuit board according to some embodiments of the present invention. Fig. 9 is a fifth exemplary diagram for explaining a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0076] This is explained again with reference to Figure 7.

[0077] The inclination angle (θ1) of the first straight line (510) may be different from the inclination angle (θ2) of the second straight line (520). The line width change section (INT) may have a concave shape in the direction in which the second test pad (330) is located. In this case, the inclination angle (θ1) of the first straight line (510) may be greater than the inclination angle (θ2) of the second straight line (520) with respect to the line width direction (D1) of the first extension wiring (320) (θ1>θ2). Although not shown in the drawing, the line width change section (INT) may also have a convex shape in the direction in which the second test pad (330) is located. In this case, the inclination angle (θ1) of the first straight line (510) may be smaller than the inclination angle (θ2) of the second straight line (520) with respect to the line width direction (D1) of the first extension wiring (320) (θ1<θ2). The fact that the inclination angle (θ1) of the first straight line (510) and the inclination angle (θ2) of the second straight line (520) are different is also the case in FIG. 10 and FIG. 11.

[0078] When the line width change section (INT) of the first extension wire (320) is divided based on the line width change starting point (430), the line width change midpoint (450), and the line width change end point (440), the line connecting the line width change starting point (430) and the line width change midpoint (450) is not limited to a straight line. Similarly, the line connecting the line width change midpoint (450) and the line width change end point (440) is not limited to a straight line.

[0079] Referring to FIG. 10, a first curve (530) may connect a line width change starting point (430) and a line width change midpoint (450), and a second curve (540) may connect a line width change midpoint (450) and a line width change end point (440). That is, the line width change starting point (430) and the line width change end point (440) may be connected by multiple curves. FIG. 10 is a sixth exemplary diagram for explaining a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0080] FIG. 10 illustrates a case where the line width change midpoint (450) is located on an extension of the first side (420) of the second test pad (330). In this case, the radius of curvature of the first curve (530) and the radius of curvature of the second curve (530) may be the same. Although not illustrated in the drawing, when the line width change starting point (430) and the line width change ending point (440) are connected to the first curve (530) and the second curve (540), the line width change midpoint (450) may not be located on an extension of the first side (420) of the second test pad (330). For example, the line width change midpoint (450) may be located inside the reference point (RP). Alternatively, the line width change midpoint (450) may be located outside the reference point (RP). In the above case, the radius of curvature of the first curve (530) and the radius of curvature of the second curve (540) may be different.

[0081] Among the lines connecting the line width change starting point (430) and the line width change midpoint (450) and the lines connecting the line width change midpoint (450) and the line width change end point (440), one line may be a straight line and the other line may be a curve. Referring to FIG. 11, a first straight line (510) may connect the line width change starting point (430) and the line width change midpoint (450), and a first curve (530) may connect the line width change midpoint (450) and the line width change end point (440). Referring to FIG. 12, a first curve (530) may connect the line width change starting point (430) and the line width change midpoint (450), and a first straight line (510) may connect the line width change midpoint (450) and the line width change end point (440). That is, the line width change starting point (430) and the line width change ending point (440) can be connected by at least one straight line and at least one curved line. Fig. 11 is a seventh exemplary diagram for explaining a test pad portion constituting a flexible circuit board according to some embodiments of the present invention. Fig. 12 is an eighth exemplary diagram for explaining a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0082] Figures 11 and 12 illustrate a case where the line width change midpoint (450) is located on an extension of the first side (420) of the second test pad (330). Although not illustrated in the drawing, when the line width change starting point (430) and the line width change ending point (440) are connected by the first straight line (510) and the first curve (530), the line width change midpoint (450) may not be located on an extension of the first side (420) of the second test pad (330).

[0083] Above, various embodiments of the first extension wire (320) have been described. FIGS. 5 to 12 illustrate a case where the gap (G1) between the first extension wire (320) and the second test pad (330) is equal to the gap (G2) between the first test pad (310) and the second test pad (330) (G1=G2). However, the present invention is not limited thereto, and the gap (G1) between the first extension wire (320) and the second test pad (330) may be different from the gap (G2) between the first test pad (310) and the second test pad (330).

[0084] Referring to FIG. 13, the gap (G2) between the first test pad (310) and the second test pad (330) may be wider than the gap (G1) between the first extension wiring (320) and the second test pad (330) (G2>G1). FIG. 13 illustrates a case where the line width change starting point (430) of the first extension wiring (320) is located inside the reference point (RP), and the line width change starting point (430) and the line width change ending point (440) are connected by a curve. Even when the gap (G2) between the first test pad (310) and the second test pad (330) is wider than the gap (G1) between the first extension wiring (320) and the second test pad (330), the examples of FIGS. 6 to 12 may be equally applied. FIG. 13 is a ninth exemplary diagram for explaining a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0085] Referring to FIG. 14, the gap (G1) between the first extension wiring (320) and the second test pad (330) may be wider than the gap (G2) between the first test pad (310) and the second test pad (330) (G1>G2). FIG. 14 illustrates a case where the line width change starting point (430) of the first extension wiring (320) is located inside the reference point (RP), and the line width change starting point (430) and the line width change ending point (440) are connected in a curve. Even when the gap (G1) between the first extension wiring (320) and the second test pad (330) is wider than the gap (G2) between the first test pad (310) and the second test pad (330), the examples of FIGS. 6 to 12 may be equally applied. FIG. 14 is a tenth exemplary view illustrating a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0086] The second test pad (330) may include a first side edge (420) and a second side edge (460). Here, the first side edge (420) refers to a side adjacent to the first test pad (310), and the second side edge (460) refers to a side adjacent to the first extension wiring (320). When the second test pad (330) includes the first side edge (420) and the second side edge (460), a portion (550) where the first side edge (420) and the second side edge (460) contact each other may be formed in the same pattern as the line width change section (INT) of the first extension wiring (320). Referring to Fig. 15, when the line width change section (INT) of the first extension wire (320) is formed as a curve, the portion (550) where the first side (420) and the second side (460) meet may also be formed as a curve. The curve formed in the line width change section (INT) of the first extension wire (320) may have a larger radius of curvature than the curve formed in the portion (550) where the first side (420) and the second side (460) meet.

[0087] However, the present invention is not limited thereto, and the portion (550) where the first side edge (420) and the second side edge (460) meet may be formed in a pattern different from the line width change section (INT) of the first extension wiring (320). Referring to FIG. 16, the line width change section (INT) of the first extension wiring (320) may be formed in a straight line, and the portion (550) where the first side edge (420) and the second side edge (460) meet may be formed in a curved line. FIG. 15 is an eleventh exemplary drawing for explaining a test pad portion constituting a flexible circuit board according to some embodiments of the present invention. FIG. 16 is a twelfth exemplary drawing for explaining a test pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0088] The flexible circuit board (100) may be formed as a multilayer board. The flexible circuit board (100) may include a plurality of wiring layers having different stacking levels. FIG. 17 is a third exemplary diagram illustrating a flexible circuit board according to some embodiments of the present invention. Referring to FIG. 17, the flexible circuit board (100) may be configured to include a substrate layer (110), a first wiring layer (120), an interlayer insulating layer (610), a second wiring layer (620), a first protective layer (130), and a first test pad portion (140). Hereinafter, only the differences compared to the case of FIG. 2 will be described.

[0089] The first wiring layer (120) and the second wiring layer (620) may be formed on the same surface of the substrate layer (110). The second wiring layer (620) may be laminated on the first wiring layer (120). An interlayer insulating layer (610) may be formed between the first wiring layer (120) and the second wiring layer (620). The first wiring layer (120) and the second wiring layer (620) may be separated by the interlayer insulating layer (610).

[0090] The interlayer insulating layer (610) may be formed with a thickness equal to that of the substrate layer (110). Alternatively, the interlayer insulating layer (610) may be formed with a thickness thinner than that of the substrate layer (110). The interlayer insulating layer (610) may be formed with an insulating resin identical to or similar to that of the substrate layer (110).

[0091] The second wiring layer (620) may be formed of an electrically conductive material identical or similar to that of the first wiring layer (120). The second wiring layer (620) may be formed on the interlayer insulating layer (610) using a manufacturing method identical or similar to that of the first wiring layer (120). In the case of FIG. 17, the first protective layer (130) may cover the second wiring layer (620).

[0092] A first test pad portion (140) may be provided to electrically test the first wiring layer (120) and the second wiring layer (620). The first test pad portion (140) may be formed at the same level as the first wiring layer (120). The first test pad portion (140) may be formed at a different level from the second wiring layer (620). The first test pad portion (140) may be electrically connected to the second wiring layer (620) through a second via (630) penetrating the interlayer insulating layer (610).

[0093] When the flexible circuit board (100) is formed as a multilayer board, a single test pad portion may be connected to multiple wiring layers, but it is also possible for multiple test pad portions to be connected to multiple wiring layers. For example, the test pad portions may be connected one-to-one with the wiring layers. Fig. 18 is a fourth exemplary diagram illustrating a flexible circuit board according to some embodiments of the present invention. Referring to Fig. 18, the flexible circuit board (100) may be configured to include a substrate layer (110), a first wiring layer (120), an interlayer insulating layer (610), a second wiring layer (620), a first protective layer (130), a first test pad portion (140), and a second test pad portion (640). Hereinafter, only the differences compared to the case of Fig. 17 will be described.

[0094] The first test pad portion (140) may be provided to electrically test the first wiring layer (120), and the second test pad portion (640) may be provided to electrically test the second wiring layer (620). The first test pad portion (140) may be formed at the same level as the first wiring layer (120), and the second test pad portion (640) may be formed at the same level as the second wiring layer (620). Various embodiments described with reference to FIGS. 5 to 16 may be equally applied to the second test pad portion (640) as well as the first test pad portion (140).

[0095] The flexible circuit board (100) may be formed as a single-sided board, but may also be formed as a double-sided board. FIG. 19 is a fifth exemplary diagram illustrating a flexible circuit board according to some embodiments of the present invention. Referring to FIG. 19, the flexible circuit board (100) may be configured to include a substrate layer (110), a first wiring layer (120), a second wiring layer (620), a first protective layer (130), a second protective layer (650), and a first test pad portion (140). Hereinafter, only the differences compared to the case of FIG. 17 will be described.

[0096] The first wiring layer (120) and the second wiring layer (620) may be formed on different surfaces of the substrate layer (110). The first wiring layer (120) may be formed on one surface of the substrate layer (110), and the second wiring layer (620) may be formed on the other surface of the substrate layer (110). The first protective layer (130) may cover the first wiring layer (120), and the second protective layer (650) may cover the second wiring layer (620). The second protective layer (650) may cover the second wiring layer (620) in the same or similar manner as the first protective layer (130).

[0097] The first test pad portion (140) may be formed on the same surface as the first wiring layer (120). In this case, the first test pad portion (140) may be electrically connected to the second wiring layer (620) through the first via (150) penetrating the substrate layer (110). Although not shown in the drawing, the first test pad portion (140) may be formed on the same surface as the second wiring layer (620). In this case, the first test pad portion (140) may be electrically connected to the first wiring layer (120) through the first via (150).

[0098] Although not shown in the drawing, the flexible circuit board (100) may further include a second test pad portion (640). In this case, the first test pad portion (140) may be provided to electrically test the first wiring layer (120), and the second test pad portion (640) may be provided to electrically test the second wiring layer (620). The first test pad portion (140) may be formed on the same surface as the first wiring layer (120), but may also be formed on a different surface from the first wiring layer (120). Similarly, the second test pad portion (640) may be formed on the same surface as the second wiring layer (620), but may also be formed on a different surface from the second wiring layer (620).

[0099] FIG. 20 is an exemplary diagram illustrating a semiconductor package including a flexible circuit board according to some embodiments of the present invention. The semiconductor package (700) may mount a semiconductor chip (710) on a flexible circuit board (100). In addition to the semiconductor chip (710), the semiconductor package (700) may also include discrete components connected to wiring layers (120, 520). The semiconductor chip (710) may be placed within an inner lead area (ILA). The semiconductor chip (710) may be electrically connected to the inner lead (220) via a bump (720). The inner lead (220) may electrically connect the semiconductor chip (710) and the electrode pattern (210). The semiconductor package (700) may be mounted on electronic products such as smartphones, digital cameras, and display devices and function as a controller. The semiconductor package (700) may serve to control electronic components such as a camera actuator. For example, the semiconductor chip (710) may be provided as an application processor (AP) or a display driver chip (DDI; Display Driver IC), and the semiconductor package (700) may be provided as a chip-on-film package (COF PKG).

[0100] FIG. 21 is an exemplary diagram illustrating an electronic device including a flexible circuit board according to some embodiments of the present invention. The electronic device (800) may be configured to include a semiconductor package (700) and an external device (810). The external device (810) may be at least one device. The external device (810) may be electrically connected to the outer lead (230). The electrode pattern (210), the inner lead (220), and the outer lead (230) may electrically connect the semiconductor chip (710) and the external device (810). For example, when the semiconductor package (700) is provided as a chip-on-film package (COF PKG) including a display driver chip (DDI), the external device (810) may be provided as a display panel.

[0101] Fig. 22 is a flowchart illustrating a method for manufacturing a flexible circuit board according to one embodiment of the present invention. Fig. 22 illustrates a case where the first wiring layer (120) and the first test pad portion (140) are formed on the same surface of the substrate layer (110).

[0102] When the substrate layer (110) is prepared (S911), a first wiring layer (120) and a first test pad portion (140) are formed on the substrate layer (110) (S912). The first wiring layer (120) and the first test pad portion (140) may be formed simultaneously.

[0103] Thereafter, a first protective layer (130) is formed on the first wiring layer (120) (S913). The first protective layer (130) covers the first wiring layer (120) and may not cover the first test pad portion (140). The first protective layer (130) may also cover part or all of the first test pad portion (140).

[0104] Figure 23 is a flowchart illustrating a method for manufacturing a flexible circuit board according to another embodiment of the present invention. Figure 23 illustrates a case where the first wiring layer (120) and the first test pad portion (140) are formed on different surfaces of the substrate layer (110).

[0105] When the substrate layer (110) is prepared (S921), a via hole penetrating the substrate layer (110) is formed (S922). The via hole is for electrically connecting the first wiring layer (120) and the first test pad portion (140).

[0106] Afterwards, a first wiring layer (120) is formed on one surface of the substrate layer (110) (S923). Next, a first test pad portion (140) is formed on the other surface of the substrate layer (110) (S924). The via hole can be filled up with metal to provide a via (150). The via (150) can be formed simultaneously with the first wiring layer (120). However, the present invention is not limited thereto, and the via (150) can also be formed simultaneously with the first test pad portion (140). Alternatively, the first wiring layer (120) can be formed, followed by the formation of the via (150), and then the formation of the first test pad portion (140).

[0107] Thereafter, a first protective layer (130) is formed on the first wiring layer (120) (S925). The protective layer may not be formed on the first test pad portion (140). A portion of the first test pad portion (140) may be covered with the protective layer.

[0108] The present invention described above is an example of a case where the increased line width of a wiring is applied to a test pad. However, the present invention is not limited to this. In the present invention, the increased line width of a wiring may also be applied to a via pad.

[0109] FIG. 24 is a sixth exemplary diagram illustrating a flexible circuit board according to some embodiments of the present invention. Referring to FIG. 24, the flexible circuit board (100) may be configured to include a substrate layer (110), a first wiring layer (120), an interlayer insulating layer (610), a second wiring layer (620), a second via (630), a first protective layer (130), a first via pad portion (660), and a second via pad portion (670). Hereinafter, descriptions of overlapping portions will be omitted, and only differences will be described.

[0110] The first via pad portion (660) may be formed on the substrate layer (110) together with the first wiring layer (120). The first via pad portion (660) may be provided as a circuit pattern on the substrate layer (110). The first via pad portion (660) may be electrically connected to the first wiring layer (120). The first via pad portion (660) may be a part of the first wiring layer (120), but is not necessarily limited thereto. The first via pad portion (660) may be formed of the same or similar material as the first wiring layer (120). The first via pad portion (660) may be formed at the same level as the first wiring layer (120). The first via pad portion (660) may be formed wider than the first wiring layer (120).

[0111] The first via pad portion (660) may include a plurality of via pads. For example, the first via pad portion (660) may include two via pads. Referring to FIG. 25, the first via pad portion (660) may include a first via pad (1010), a second via pad (1020), a third extension wiring (1030), and a fourth extension wiring (1040). FIG. 25 is a first exemplary diagram illustrating a via pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0112] The first via pad (1010) may be electrically connected to a third extension wiring (1030) extended from a circuit pattern in the first wiring layer (120). The second via pad (1020) may be electrically connected to a fourth extension wiring (1040) extended from a circuit pattern in the first wiring layer (120). The first via pad (1010) and the second via pad (1020) may be positioned considering a limited space. The first via pad (1010) may be positioned behind the second via pad (1020). The third extension wiring (1030) may pass through the second via pad (1020) and be connected to the first via pad (1010). In this case, the problem described with reference to FIG. 1 may also occur in the case of the via pad.

[0113] The third extension wire (1030) passing through the second via pad (1020) may have its line width expanded adjacent to the first via pad (1010). The line width change starting point of the third extension wire (1030) may be positioned at a point where stress distribution is possible. The line width change starting point of the third extension wire (1030) may not be located on an extension line of the side of the second via pad (1020). The line width change of the first extension wire (320) described above with reference to FIGS. 5 to 16 may be equally applied to the third extension wire (1030).

[0114] The first via pad (1010) and the second via pad (1020) may each be electrically connected to a single extension wire. However, the present invention is not limited thereto, and the first via pad (1010) and the second via pad (1020) may each be electrically connected to a plurality of extension wires. Referring to FIG. 26, the first via pad portion (660) may include the first via pad (1010), the second via pad (1020), the third extension wire (1030), the fourth extension wire (1040), the fifth extension wire (1050), and the sixth extension wire (1060). FIG. 26 is a second exemplary diagram for explaining a via pad portion constituting a flexible circuit board according to some embodiments of the present invention.

[0115] The first via pad (1010) may be electrically connected to a third extension wiring (1030) and a fifth extension wiring (1050) extended from a circuit pattern in the first wiring layer (120). The third extension wiring (1030) may be connected to one side of the first via pad (1010), and the fifth extension wiring (1050) may be connected to the other side of the first via pad (1010). The second via pad (1020) may be electrically connected to a fourth extension wiring (1040) and a sixth extension wiring (1060) extended from a circuit pattern in the first wiring layer (120). The fourth extension wiring (1040) may be connected to one side of the second via pad (1020), and the sixth extension wiring (1060) may be connected to the other side of the second via pad (1020).

[0116] The third extension wiring (1030) may be connected to the first via pad (1010) via the second via pad (1020). In this case, the problem described with reference to FIG. 1 may occur. To solve the problem, the line width of the third extension wiring (1030) passing through the second via pad (1020) may be expanded adjacent to the first via pad (1010). Various embodiments described with reference to FIGS. 5 to 16 may be equally applied to the change in line width of the third extension wiring (1030).

[0117] Similarly, the sixth extension wiring (1060) may pass through the first via pad (1010) and be connected to the second via pad (1020). In this case, the problem described with reference to FIG. 1 may also occur. To solve the problem, the line width of the sixth extension wiring (1060) passing through the first via pad (1010) may be expanded adjacent to the second via pad (1020). Various embodiments described with reference to FIGS. 5 to 16 may be equally applied to the change in line width of the sixth extension wiring (1060).

[0118] This is explained again with reference to Figure 24.

[0119] The second via pad portion (670) may be formed on the interlayer insulating layer (610) together with the second wiring layer (620). The second via pad portion (670) may be provided as a circuit pattern on the interlayer insulating layer (610). The second via pad portion (670) may be electrically connected to the second wiring layer (620). The formation conditions of the second via pad portion (670) considering the second wiring layer (620) may be the same as the formation conditions of the first via pad portion (660) considering the first wiring layer (120).

[0120] The second via pad portion (670) may include a plurality of via pads. For example, the second via pad portion (670) may include two via pads. The two via pads may be arranged in consideration of limited space. One of the two via pads may be arranged behind the other via pad. The various embodiments described with reference to FIGS. 5 to 16 may be equally applied to the second via pad portion (670) as well as the first via pad portion (660).

[0121] The first via pad portion (660) and the second via pad portion (670) may be electrically connected through the second via (630) in the via hole (VH). Although not shown in the drawing, the first via pad portion (660) may also be directly connected to the second wiring layer (620). Alternatively, the first via pad portion (660) may not be electrically connected to the second wiring layer (620). In this case, the flexible circuit board (100) may not include the second via pad portion (670).

[0122] The first via pad portion (660) may be covered by the interlayer insulating layer (610). The entire first via pad portion (660) may be covered by the interlayer insulating layer (610), but a portion of the first via pad portion (660) may also be covered by the interlayer insulating layer (610). However, the present invention is not limited thereto, and the first via pad portion (660) may not be covered by the interlayer insulating layer (610). Similarly, the second via pad portion (670) may be covered by the first protective layer (130). The entire second via pad portion (670) may be covered by the first protective layer (130), but a portion of the second via pad portion (670) may also be covered by the first protective layer (130). However, the present invention is not limited thereto, and the second via pad portion (670) may not be covered by the first protective layer (130).

[0123] Fig. 24 illustrates a flexible circuit board (100) including via pad portions (660, 670). Although not shown in the drawing, the flexible circuit board (100) may also include both via pad portions (660, 670) and test pad portions (140, 640). In the present invention, the via pad portions (660, 670) and the test pad portions (140, 640) are collectively referred to as pad portions. The first via pad portion (660) and the first test pad portion (140) are collectively referred to as the first pad portion, and the second via pad portion (670) and the second test pad portion (640) are collectively referred to as the second pad portion. The first test pad (310) and the first via pad (1010) are collectively referred to as the first pad, and the second test pad (330) and the second via pad (1020) are collectively referred to as the second pad.

[0124] When the flexible circuit board (100) includes both a via pad portion (660, 670) and a test pad portion (140, 640), the various embodiments described with reference to FIGS. 5 to 16 may be applied to both the via pad portion (660, 670) and the test pad portion (140). Alternatively, the various embodiments described with reference to FIGS. 5 to 16 may be applied to either the via pad portion (660, 670) or the test pad portion (140).

[0125] Although embodiments of the present invention have been described with reference to the attached drawings, the present invention is not limited to the above embodiments, but can be manufactured in various different forms. Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential characteristics of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

[0126] The present invention is used to manufacture semiconductor packages and can be applied to circuit boards mounted on electronic devices.

Claims

1. Base layer; A wiring layer formed on the above substrate layer; and It includes a pad portion electrically connected to the above wiring layer, The above pad part, 1st pad; Second pad; and It includes an extension wiring extending from the above wiring layer and connecting to the first pad through the second pad, A flexible circuit board in which the starting point of the line width change of the above-mentioned extended wiring is not located on the extension line of the first side of the second pad adjacent to the first pad.

2. In paragraph 1, A flexible circuit board in which the line width change starting point is a point further from the first pad than the reference point of the extended wiring located on the extended line.

3. In paragraph 1, The above extension wiring is a flexible circuit board whose line width is expanded based on the line width change starting point.

4. In paragraph 1, The line width change section of the above extension wiring is: The above line width change starting point; and A flexible circuit board comprising a line width change endpoint contacting a first side of the first pad adjacent to the second pad.

5. In paragraph 4, A flexible circuit board in which the above line width change starting point and the above line width change ending point are connected by either a straight line or a curved line.

6. In paragraph 5, The above curve is a flexible circuit board having a concave shape in the direction in which the second pad is located.

7. In paragraph 4, The above line width change section is, A flexible circuit board further comprising a line width change midpoint located between the line width change starting point and the line width change ending point.

8. In paragraph 7, A flexible circuit board in which the first line connecting the line width change starting point and the line width change midpoint is the same type of line as the second line connecting the line width change midpoint and the line width change end point.

9. In paragraph 8, A flexible circuit board wherein the angle of inclination of the first line with respect to the line width direction of the extension wiring is different from the angle of inclination of the second line with respect to the line width direction of the extension wiring.

10. In paragraph 9, A flexible circuit board in which the inclination angle of the first line is greater than the inclination angle of the second line.

11. In paragraph 7, A flexible circuit board in which the first line connecting the line width change starting point and the line width change midpoint is a different type of line from the second line connecting the line width change midpoint and the line width change end point.

12. In paragraph 1, The above second pad, The first side above; and Including a second side adjacent to the above extension wire, A flexible circuit board in which the portion where the first side and the second side are in contact is formed with the same pattern as the line width change section of the extended wiring.

13. In paragraph 1, A flexible circuit board in which the above pad portion is formed on the same surface as the wiring layer and the substrate layer.

14. In paragraph 1, The above pad portion is formed on different surfaces of the wiring layer and the substrate layer, A flexible circuit board in which the pad portion is connected to the wiring layer through a via penetrating the substrate layer.

15. In paragraph 1, The above pad portion is a flexible circuit board that is a test pad portion or a via pad portion for inspecting the wiring layer.

16. Flexible circuit board; and A semiconductor chip mounted on the flexible circuit board and electrically connected to a wiring layer within the flexible circuit board through a bump, The above flexible circuit board is, substrate layer; A wiring layer formed on the above substrate layer; and It includes a pad portion electrically connected to the above wiring layer, The above pad part, 1st pad; Second pad; and It includes an extension wiring extending from the above wiring layer and connecting to the first pad through the second pad, A semiconductor package in which the starting point of the line width change of the above-mentioned extended wiring is not located on the extension line of the first side of the second pad adjacent to the first pad.

17. A semiconductor package including a flexible circuit board and a semiconductor chip; and An external device electrically connected to the semiconductor chip through the flexible circuit board, The above flexible circuit board is, substrate layer; A wiring layer formed on the above substrate layer; and It includes a pad portion electrically connected to the above wiring layer, The above pad part, 1st pad; Second pad; and It includes an extension wiring extending from the above wiring layer and connecting to the first pad through the second pad, An electronic device in which the starting point of the line width change of the above-mentioned extended wiring is not located on the extension line of the first side of the second pad adjacent to the first pad.

18. A step of forming a wiring layer on a substrate layer; and It includes a step of forming a pad portion electrically connected to the wiring layer on the above substrate layer, The above pad part, 1st pad; Second pad; and It includes an extension wiring extending from the above wiring layer and connecting to the first pad through the second pad, A method for manufacturing a flexible circuit board, wherein the starting point of the line width change of the above-mentioned extended wiring is not located on the extension line of the first side of the second pad adjacent to the first pad.

19. In paragraph 18, A method for manufacturing a flexible circuit board in which the pad portion is formed on the same surface as the wiring layer and the substrate layer, and the pad portion is formed simultaneously with the wiring layer.

20. In paragraph 18, When the above pad portion is formed on different surfaces of the wiring layer and the substrate layer, A method for manufacturing a flexible circuit board, further comprising the step of forming a via penetrating the substrate layer.

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