Wired circuit board

Abstract

To provide a wiring circuit board capable of suppressing peeling of an insulating layer from a metal support layer even when a water absorption rate of the insulating layer is high.SOLUTION: A wiring circuit board 1 includes a metal support layer 2, a first insulating layer 3, a terminal 41, and a heat radiation layer 6. The first insulating layer 3 is made of polyimide and has a water absorption rate of 0.40% or more. The heat releasing layer 6 is disposed at the opposite side to the terminal 41 with respect to the first insulating layer 3, and is disposed between the metal supporting layer 2 and the first insulating layer 3. The heat releasing layer 6 is in contact with both of the metal supporting layer 2 and the first insulating layer 3.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a printed circuit board. [Background technology]

[0002] Conventionally, a wired circuit board has been known which includes a metal support layer, a base insulating layer arranged on one surface of the metal support layer in the thickness direction, and a conductor pattern arranged on one surface of the base insulating layer in the thickness direction (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-171201 Summary of the Invention [Problem to be solved by the invention]

[0004] In a wired circuit board such as that described in Patent Document 1, if the base insulating layer has a high water absorption rate, when the heat of the molten solder is transmitted to the base insulating layer through the terminals of the conductive pattern, voids are generated due to the evaporation of water in the base insulating layer, which causes the base insulating layer to easily peel off from the metal support layer.

[0005] The present invention provides a wired circuit board that can suppress peeling of an insulating layer from a metal support layer even when the insulating layer has a high water absorption rate. [Means for solving the problem]

[0006] The present invention [1] includes a wired circuit board comprising a metal support layer, an insulating layer arranged on one side of the metal support layer in the thickness direction of the metal support layer, made of polyimide and having a water absorption rate of 0.40% or more, a terminal arranged on one surface of the insulating layer in the thickness direction, and a heat dissipation layer arranged on the opposite side of the terminal with respect to the insulating layer in the thickness direction, and arranged between the metal support layer and the insulating layer in the thickness direction, and in contact with both the metal support layer and the insulating layer.

[0007] According to this configuration, the heat dissipation layer is provided between the metal support layer and the insulating layer.

[0008] Therefore, when the heat of the molten solder is transferred to the insulating layer via the terminal, the heat transferred to the insulating layer can be diffused to the heat dissipation layer and transferred to the metal support layer via the heat dissipation layer.

[0009] This makes it possible to prevent the heat of the molten solder from accumulating in the insulating layer.

[0010] As a result, even if the insulating layer has a high water absorption rate, peeling of the insulating layer from the metal support layer can be suppressed.

[0011] The present invention [2] includes the wired circuit board according to the above [1], wherein the area of ​​the heat dissipation layer in a direction perpendicular to the thickness direction is equal to or larger than the area of ​​the terminals.

[0012] With this configuration, the heat transferred to the insulating layer via the terminals can be reliably diffused to the heat dissipation layer.

[0013] The present invention [3] includes the wired circuit board according to the above [1] or [2], wherein the thermal conductivity of the heat dissipation layer is higher than the thermal conductivity of the metal support layer.

[0014] With this configuration, the heat transferred to the insulating layer via the terminals can be smoothly diffused to the heat dissipation layer.

[0015] The present invention [4] includes the wired circuit board of any one of the above [1] to [3], wherein the heat dissipation layer has a thickness of 0.5 μm or more.

[0016] With this configuration, the volume of the heat dissipation layer can be secured.

[0017] Therefore, the heat transferred to the insulating layer via the terminals can be reliably diffused to the heat dissipation layer.

[0018] The present invention [5] comprises the wired circuit board of any one of the above [1] to [4], wherein the thickness of the insulating layer between the terminal and the heat dissipation layer is 50 μm or less.

[0019] With this configuration, it is possible to prevent the heat of the molten solder from accumulating in the insulating layer, and to smoothly dissipate the heat transferred to the insulating layer via the terminals to the heat dissipation layer.

[0020] The present invention [6] includes the wired circuit board of any one of the above [1] to [5], wherein the ratio of the area of ​​the terminal in a direction perpendicular to the thickness direction to the thickness of the insulating layer is 5000 μm or more.

[0021] With this configuration, it is possible to prevent the heat of the molten solder from accumulating in the insulating layer, and to smoothly dissipate the heat transferred to the insulating layer via the terminals to the heat dissipation layer. [Effects of the Invention]

[0022] According to the wired circuit board of the present invention, even if the insulating layer has a high water absorption rate, peeling of the insulating layer from the metal support layer can be suppressed. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a plan view of one embodiment of the wired circuit board of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the printed circuit board shown in FIG. 1 taken along the line AA. [Figure 3]Figures 3A to 3D show the manufacturing process of the wired circuit board shown in Figure 2, where Figure 3A shows the heat dissipation layer formation process, Figure 3B shows the first insulating layer formation process, Figure 3C shows the process of forming the first conductor layer of the terminal and wiring in the conductor pattern formation process, and Figure 3D shows the process of forming the second conductor layer of the terminal in the conductor pattern formation process. DETAILED DESCRIPTION OF THE INVENTION

[0024] 1. Wiring circuit board As shown in Figure 1, the wired circuit board 1 extends in a first direction and a second direction. The second direction is perpendicular to the first direction. The shape of the wired circuit board 1 is not limited. The wired circuit board 1 may be a flexible wired circuit board or a circuit-equipped suspension board.

[0025] As shown in FIG. 2, the wired circuit board 1 includes a metal support layer 2, a first insulating layer 3 as an example of an insulating layer, a conductive pattern 4, a second insulating layer 5, and a heat dissipation layer 6.

[0026] (1) Metal support layer The metal support layer 2 supports the first insulating layer 3, the conductive pattern 4, the second insulating layer 5, and the heat dissipation layer 6. Examples of materials for the metal support layer 2 include stainless steel and copper alloys. The metal support layer 2 is preferably made of a copper alloy.

[0027] The thermal conductivity of the metal support layer 2 is, for example, 50 W / m·K to 350 W / m·K.

[0028] The thermal conductivity is determined according to JIS H 7903:2008 (effective thermal conductivity measurement method).

[0029] (2) First insulating layer The first insulating layer 3 is disposed on one side of the metal support layer 2 in the thickness direction of the metal support layer 2. The first insulating layer 3 is disposed away from the metal support layer 2 in the thickness direction. The first insulating layer 3 is disposed between the conductive pattern 4 and the metal support layer 2 in the thickness direction. The first insulating layer 3 is disposed between the conductive pattern 4 and the heat dissipation layer 6 in the thickness direction. The first insulating layer 3 insulates the metal support layer 2 and the heat dissipation layer 6 from the conductive pattern 4. The first insulating layer 3 is made of polyimide. When the first insulating layer 3 contains fluorine, the water absorption rate of the first insulating layer tends to increase as the fluorine content decreases. The first insulating layer 3 preferably does not contain fluorine.

[0030] The water absorption rate of the first insulating layer 3 is 0.40% or more. If the water absorption rate of the first insulating layer 3 is equal to or greater than the lower limit, when heat from the molten solder is transmitted to the first insulating layer 3 via the terminals 41 of the conductive pattern 4, the first insulating layer 3 may be easily peeled off from the metal support layer 2.

[0031] The water absorption rate of the first insulating layer 3 is, for example, 0.80% or less, or preferably 0.60% or less.

[0032] Between the terminals 41 of the conductive pattern 4 and the heat dissipation layer 6, the thickness T1 of the first insulating layer 3 is, for example, 50 μm or less, or preferably 30 μm or less. When the thickness T1 of the first insulating layer 3 is equal to or less than the above upper limit, the heat of the molten solder is prevented from accumulating in the first insulating layer 3, and the heat transferred to the first insulating layer 3 via the terminals 41 can be smoothly diffused to the heat dissipation layer 6.

[0033] The thickness T1 of the first insulating layer 3 is, for example, 1 μm or more, or preferably 3 μm or more. When the thickness T1 of the first insulating layer 3 is equal to or more than the above lower limit, the metal support layer 2 and the heat dissipation layer 6 can be insulated from the terminal 41.

[0034] (4) Conductor pattern The conductor pattern 4 is disposed on one side of the first insulating layer 3 in the thickness direction. The conductor pattern 4 is disposed on one surface of the first insulating layer 3 in the thickness direction. The conductor pattern 4 is disposed on the opposite side of the metal support layer 2 with respect to the first insulating layer 3 in the thickness direction. The conductor pattern 4 is made of a metal. Examples of metals include copper, silver, gold, iron, aluminum, chromium, and alloys thereof. Copper is preferable from the viewpoint of obtaining good electrical properties. The shape of the conductor pattern 4 is not limited. The conductor pattern 4 has a terminal 41 and a wiring 42.

[0035] The terminal 41 is disposed on one surface of the first insulating layer 3 in the thickness direction. The terminal 41 extends in the first and second directions. The terminal 41 has, for example, a substantially rectangular shape (see FIG. 1). The shape of the terminal 41 is not limited. The terminal 41 may have a circular shape. The wired circuit board 1 may have multiple terminals 41. When the wired circuit board 1 has multiple terminals 41, the multiple terminals 41 are lined up, for example, in the first direction.

[0036] The dimension L1 of the terminal 41 in the first direction is in the range of, for example, 50 μm to 1000 μm, or preferably 100 μm to 800 μm.

[0037] The dimension L2 of the terminal 41 in the second direction is in the range of, for example, 50 μm to 1000 μm, or preferably 100 μm to 800 μm.

[0038] In the direction perpendicular to the thickness direction, the area S of the terminal 41 is, for example, 10000 μm 2 ~800,000μm 2 , preferably 50,000 μm 2 ~500,000μm 2 is.

[0039] The dimensions L1 and L2 are the dimensions of the other surface of terminal 41 in the thickness direction (the surface in contact with first insulating layer 3). The area of ​​terminal 41 is the area of ​​the other surface of terminal 41 in the thickness direction (the surface in contact with first insulating layer 3).

[0040] The ratio (S / T1) of the area S of the terminal 41 to the thickness T1 of the first insulating layer 3 is, for example, 5,000 μm or more, preferably 10,000 μm or more, and more preferably 20,000 μm or more. When the area S of the terminal 41 is larger relative to the thickness T1 of the first insulating layer 3, the amount of heat accumulated per unit area in the first insulating layer 3 can be reduced. Furthermore, when the thickness T1 of the first insulating layer 3 is smaller relative to the area S of the terminal 41, the accumulation of heat from the molten solder in the first insulating layer 3 can be suppressed, and the heat conducted to the first insulating layer 3 via the terminal 41 can be smoothly diffused to the heat dissipation layer 6. The ratio (S / T1) may be, for example, 50,000 μm or less, or 30,000 μm or less.

[0041] The terminal 41 may have a first conductor layer 411 and a second conductor layer 412. The first conductor layer 411 is disposed on one surface of the first insulating layer 3 in the thickness direction. The second conductor layer 412 is disposed on one surface of the first conductor layer 411 in the thickness direction. In the thickness direction, one surface of the second conductor layer 412 is disposed on one side of the second insulating layer 5. The terminal 41 does not have to have the second conductor layer 412.

[0042] The wiring 42 is connected to the terminal 41. The wiring 42 may be connected to the first conductor layer 411 of the terminal 41 or may be connected to the second conductor layer 412 of the terminal 41.

[0043] (5) Second insulating layer The second insulating layer 5 is disposed on one surface of the first insulating layer 3 in the thickness direction. The second insulating layer 5 covers the wiring 42. The second insulating layer 5 may cover the peripheral portion of the terminal 41. When the terminal 41 has a first conductor layer 411 and a second conductor layer 412, the second insulating layer 5 may cover the peripheral portion of the first conductor layer 411. The second insulating layer 5 does not cover at least the center portion of the terminal 41. When the terminal 41 has a first conductor layer 411 and a second conductor layer 412, the second insulating layer 5 does not cover the second conductor layer 412. The second insulating layer 5 is made of a resin. Examples of resins include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester. The second insulating layer 5 is preferably made of polyimide.

[0044] (6) Heat dissipation layer The heat dissipation layer 6 is disposed on one side of the metal support layer 2 in the thickness direction of the metal support layer 2. The heat dissipation layer 6 is disposed on one surface of the metal support layer 2 in the thickness direction. The heat dissipation layer 6 is disposed between the metal support layer 2 and the first insulating layer 3 in the thickness direction. The heat dissipation layer 6 is in contact with both the metal support layer 2 and the first insulating layer 3. The heat dissipation layer 6 is disposed at least on the opposite side of the first insulating layer 3 from the terminal 41 in the thickness direction. This allows the heat of the molten solder to be diffused to the heat dissipation layer 6 and transferred to the metal support layer 2 via the heat dissipation layer 6. This prevents the heat of the molten solder from accumulating in the first insulating layer 3. As a result, even if the first insulating layer 3 has a high water absorption rate (water absorption rate of 0.40% or more), peeling of the first insulating layer 3 from the metal support layer 2 can be prevented. The heat dissipation layer 6 may be disposed on the opposite side of the first insulating layer 3 from all of the conductive patterns 4 in the thickness direction.

[0045] The heat dissipation layer 6 extends in a direction perpendicular to the thickness direction. In the direction perpendicular to the thickness direction, the area of ​​the heat dissipation layer 6 is equal to or larger than the area S of the terminal. Therefore, the heat transferred to the first insulating layer 3 via the terminal 41 can be reliably diffused to the heat dissipation layer 6.

[0046] The thermal conductivity of the heat dissipation layer 6 is higher than that of the metal support layer 2. Therefore, heat transferred to the first insulating layer 3 via the terminal 41 can be smoothly diffused to the heat dissipation layer 6. The thermal conductivity of the heat dissipation layer 6 is, for example, 300 W / m·K or more, or preferably 350 W / m·K or more. The thermal conductivity of the heat dissipation layer 6 is, for example, 450 W / m·K or less.

[0047] The material of the heat dissipation layer 6 is different from the material of the metal support layer 2. The heat dissipation layer 6 is made of a metal. Examples of metals include copper, silver, aluminum, gold, nickel, and platinum. The heat dissipation layer 6 is preferably made of copper.

[0048] The thickness T2 of the heat dissipation layer 6 may be thinner than the thickness of the metal support layer 2. The thickness T2 of the heat dissipation layer 6 is, for example, 0.5 μm or more, preferably 1 μm or more. When the thickness T2 of the heat dissipation layer 6 is equal to or greater than the above lower limit, the volume of the heat dissipation layer 6 can be ensured. Therefore, the heat transferred to the first insulating layer 3 via the terminal 41 can be reliably diffused to the heat dissipation layer 6. The thickness T2 of the heat dissipation layer 6 is, for example, 20 μm or less, preferably 10 μm or less.

[0049] 2. Manufacturing method of printed circuit board Next, a method for manufacturing the wired circuit board 1 will be described.

[0050] The method for manufacturing the wired circuit board 1 includes a heat dissipation layer forming step (see FIG. 3A), a first insulating layer forming step (see FIG. 3B), a conductor pattern forming step (see FIGS. 3C and 3D), and a second insulating layer forming step (see FIG. 2).

[0051] (1) Heat dissipation layer formation process As shown in FIG. 3A, in the heat dissipation layer forming step, a heat dissipation layer 6 is formed on one surface of the metal support layer 2 in the thickness direction by, for example, electrolytic plating.

[0052] (2) First insulating layer formation process Next, as shown in FIG. 3B, in the first insulating layer forming step, the first insulating layer 3 is formed on one surface of the heat dissipation layer 6 in the thickness direction.

[0053] More specifically, first, a photosensitive polyimide solution (varnish) is applied to one surface of the heat dissipation layer 6 and dried to form a photosensitive polyimide coating film.

[0054] Next, the photosensitive polyimide coating is exposed to light and developed, thereby forming the first insulating layer 3.

[0055] (3) Conductor pattern formation process Next, as shown in FIGS. 3C and 3D, in the conductive pattern forming step, a conductive pattern 4 is formed on one surface of the first insulating layer 3 in the thickness direction.

[0056] As shown in FIG. 3C, in the conductive pattern forming step, first, the first conductive layer 411 of the terminal 41 and the wiring 42 are formed.

[0057] Specifically, a seed layer is formed on one surface of the first insulating layer 3 in the thickness direction. The seed layer is formed by, for example, sputtering. Examples of materials for the seed layer include chromium, copper, nickel, titanium, and alloys thereof.

[0058] Next, one surface of the first insulating layer 3 in the thickness direction is covered with a first plating resist.

[0059] Next, the first plating resist is exposed and developed, thereby removing the first plating resist from the portions where the first conductor layer 411 of the terminal 41 and the wiring 42 are to be formed, and exposing the seed layer from the portions where the first conductor layer 411 of the terminal 41 and the wiring 42 are to be formed. On the other hand, the first plating resist remains in the portions where the first conductor layer 411 of the terminal 41 and the wiring 42 are not to be formed.

[0060] Next, on the exposed seed layer, first conductor layer 411 of terminal 41 and wiring 42 are formed by electrolytic plating. After the electrolytic plating is completed, the first plating resist is peeled off.

[0061] Next, as shown in FIG. 3D, in the conductive pattern forming step, the second conductive layer 412 of the terminal 41 is formed.

[0062] Specifically, one surface of the first insulating layer 3 in the thickness direction, the first conductor layer 411, and the wiring 42 are covered with the second plating resist.

[0063] Next, the second plating resist is exposed and developed, thereby removing the second plating resist from the portion where the second conductor layer 412 is to be formed, and exposing the first conductor layer 411 in the portion where the second conductor layer 412 is to be formed. On the other hand, the second plating resist remains in the portion where the second conductor layer 412 is not to be formed.

[0064] Next, second conductor layer 412 is formed by electrolytic plating on exposed first conductor layer 411. After electrolytic plating is completed, the second plating resist is stripped off. Thereafter, the seed layer exposed by the stripping of the second plating resist is removed by etching.

[0065] In this way, the conductive pattern 4 is formed.

[0066] (4) Second insulating layer formation process Next, as shown in FIG. 2, in the second insulating layer forming step, a second insulating layer 5 is formed on one surface of the first insulating layer 3 in the thickness direction.

[0067] More specifically, in the second insulating layer forming step, first, a photosensitive resin solution (varnish) is applied to the conductive pattern 4 and the first insulating layer 3 and dried to form a photosensitive resin coating.

[0068] Next, the photosensitive resin coating is exposed to light and developed, thereby forming the second insulating layer 5 on the first insulating layer 3.

[0069] 3. Effects As shown in FIG. 2, the wired circuit board 1 includes a heat dissipation layer 6 between the metal support layer 2 and the first insulating layer 3.

[0070] Therefore, when the heat of the molten solder is transmitted to the first insulating layer 3 via the terminal 41, the heat transmitted to the first insulating layer 3 can be diffused to the heat dissipation layer 6 and transmitted to the metal support layer 2 via the heat dissipation layer 6.

[0071] Therefore, accumulation of heat from the molten solder in the first insulating layer 3 can be suppressed.

[0072] As a result, even if the water absorption rate of the first insulating layer 3 is high (water absorption rate of 0.40% or more), peeling of the first insulating layer 3 from the metal support layer 2 can be suppressed. [Example]

[0073] The present invention will be described in more detail below with reference to examples and comparative examples. It should be noted that the present invention is not limited to these examples and comparative examples. The specific numerical values ​​of the blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be substituted with the upper limit (a numerical value defined as "equal to or less than") or lower limit (a numerical value defined as "equal to or more than" or "exceeding") of the corresponding blending ratios (content ratios), physical property values, parameters, etc. described in the "Description of the Invention" above.

[0074] 1. Manufacturing of printed circuit boards (1) Example 1 First, a metal support layer made of a copper alloy was prepared.

[0075] Next, a heat dissipation layer was formed on one surface of the metal support layer by electrolytic plating (heat dissipation layer forming step).

[0076] Next, a photosensitive polyimide solution (varnish) was applied to the surface of the heat dissipation layer and dried, thereby forming a photosensitive polyimide coating on the surface of the heat dissipation layer.

[0077] Next, the photosensitive polyimide coating was exposed to light and developed, thereby forming a first insulating layer made of polyimide on the surface of the heat dissipation layer (first insulating layer forming step).

[0078] Next, a seed layer made of chromium was formed on the first insulating layer by sputtering.

[0079] Next, the first insulating layer was covered with a first plating resist, which was exposed and developed, thereby removing the first plating resist from the areas where the first conductor layer and wiring of the terminals were to be formed, and exposing the seed layer in the areas where the first conductor layer and wiring were to be formed.

[0080] Next, a first conductor layer made of copper and wiring made of copper were formed on the exposed seed layer by electrolytic plating. After the electrolytic plating was completed, the first plating resist was peeled off.

[0081] Next, the first insulating layer, the first conductor layer, and the wiring were covered with a second plating resist, which was then exposed and developed, removing the second plating resist from the area where the second conductor layer of the terminal was to be formed, and exposing the first conductor layer where the second conductor layer was to be formed.

[0082] Next, a second conductor layer was formed on the exposed first conductor layer by electrolytic plating. After electrolytic plating was completed, the second plating resist was stripped off, and the seed layer exposed by the stripping of the second plating resist was removed by etching. This resulted in the formation of a conductor pattern on the first insulating layer (conductor pattern forming step).

[0083] Next, a photosensitive polyimide solution (varnish) was applied onto the first insulating layer and the conductive pattern and dried to form a photosensitive polyimide coating film.

[0084] Next, the photosensitive polyimide coating film was exposed to light and developed, thereby forming a second insulating layer on the first insulating layer (second insulating layer forming step). In this way, a wired circuit board was obtained.

[0085] The ratio of the area of ​​the terminal to the thickness of the first insulating layer (S / T1) was 26042.

[0086] (2) Example 2 A wired circuit board having a conductor pattern with the same shape as the conductor pattern of Example 1 was obtained in the same manner as in Example 1, except that a photosensitive polyimide with a water absorption rate of 0.49% was used.

[0087] (3) Comparative Example 1 A wired circuit board having a conductor pattern with the same shape as the conductor pattern of Example 1 was obtained in the same manner as in Example 1, except that a photosensitive polyimide with a water absorption rate of 0.38% was used.

[0088] (4) Comparative Example 2 A wired circuit board having a conductor pattern of the same shape as the conductor pattern of Example 1 was obtained in the same manner as in Example 1, except that a photosensitive polyimide with a water absorption rate of 0.38% was used and no heat dissipation layer was formed.

[0089] (5) Comparative Example 3 A wired circuit board having a conductor pattern with the same shape as the conductor pattern of Example 1 was obtained in the same manner as in Example 1, except that no heat dissipation layer was formed.

[0090] (6) Comparative Example 4 A wired circuit board having a conductor pattern with the same shape as the conductor pattern of Example 1 was obtained in the same manner as in Example 2, except that no heat dissipation layer was formed.

[0091] 2. Physical property measurements (1) Water absorption rate of the first insulating layer The water absorption rate of the first insulating layer of the wired circuit board obtained in each example and each comparative example was measured by the following method. The results are shown in Table 1.

[0092] Using a thermogravimetric-differential thermal analyzer (TG-DTA), the temperature was raised from room temperature (25°C) to 100°C at a heating rate of 5°C / min, and the rate of decrease in the mass M2 of the first insulating layer at 100°C relative to the mass M1 of the first insulating layer at room temperature (25°C) was calculated using the following formula to obtain the water absorption rate.

[0093] Formula: Water absorption rate (%) = (M1-M2) / M1×100 (2) Share strength The shear strength of the first insulating layer of the wired circuit board obtained in each example and each comparative example was measured.

[0094] Specifically, solder was placed on one surface of the second conductor layer of the terminal in the thickness direction (see FIG. 2), and the solder was heated and melted using a laser with an output of 0.15 J.

[0095] Next, a shear force was applied to the first insulating layer along the second direction (see Figure 2) using a blade. The shear force at which the first insulating layer peeled off from the heat dissipation layer or the metal support layer was defined as the shear strength. The measured shear strengths are shown in Table 1.

[0096] [Table 1] [Explanation of symbols]

[0097] 1 Wiring circuit board 2 Metal support layer 6 Heat dissipation layer 41 terminals

Claims

1. a metal support layer; an insulating layer that is arranged on one side of the metal support layer in the thickness direction of the metal support layer, is made of polyimide, and has a water absorption rate of 0.40% or more; a terminal disposed on one surface of the insulating layer in the thickness direction; a heat dissipation layer that is disposed on the opposite side of the insulating layer from the terminals in the thickness direction, and that is disposed between the metal support layer and the insulating layer in the thickness direction, and that is in contact with both the metal support layer and the insulating layer; A wired circuit board comprising:

2. The printed circuit board according to claim 1 , wherein an area of ​​said heat dissipation layer in a direction perpendicular to said thickness direction is equal to or larger than an area of ​​said terminals.

3. The printed circuit board according to claim 1 , wherein the heat dissipation layer has a thermal conductivity higher than that of the metal support layer.

4. 2. The printed circuit board according to claim 1, wherein the heat dissipation layer has a thickness of 0.5 [mu]m or more.

5. 2. The printed circuit board according to claim 1, wherein the insulating layer between the terminal and the heat dissipation layer has a thickness of 50 [mu]m or less.

6. 2. The wired circuit board according to claim 1, wherein a ratio of an area of ​​said terminal in a direction perpendicular to the thickness direction to a thickness of said insulating layer is 5000 [mu]m or more.

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