A microvia filling process in integrated circuits

Abstract

The present invention discloses a micropore filling process in an integrated circuit, comprising the following steps: (1) selecting metal as a filling material, and extending part of the metal into micropores arranged on a substrate; (2) melting and / or fusing the metal under a controlled atmosphere, and the molten metal fills the micropores through a capillary phenomenon; (3) polishing the surface of the filled micropores; (4) pattern electroplating the substrate, so that the micropores on the substrate are interconnected to form a circuit layer, thereby obtaining a carrier board with a circuit layer. The process can achieve micropore filling with a large depth-to-neck ratio, and will not cause defects such as hole and clamp filling. In addition, the hole filling efficiency in the process is higher.

Description

Technical Field

[0001] The invention relates to the field of semiconductor and integrated circuit manufacturing, and in particular to a micro-hole filling process in an integrated circuit. Background Art

[0002] An integrated circuit is a miniature electronic device or component. Using a certain process, the transistors, resistors, capacitors, inductors and other components and wiring required in a circuit are interconnected and made on a small piece or several small pieces of semiconductor wafers or dielectric substrates, and then packaged in a tube shell to become a miniature structure with the required circuit function; all the components have formed a whole in structure, making electronic components a big step forward in miniaturization, low power consumption, intelligence and high reliability.

[0003] As the application of electronic products becomes more and more extensive, the demand for small-sized and powerful integrated circuits and circuit boards is also increasing. In the manufacturing process of integrated circuits or circuit boards, through holes or blind holes are usually set on each layer of the integrated circuit or circuit board, and the interconnection of each layer is realized through the hole filling process, thereby reducing delays, reducing energy consumption and improving integration. It plays a vital role in the fields of advanced packaging technologies such as 2.5D / 3D packaging, WLCSP, SiP, Fan out, etc. At present, the electroplating copper hole filling process is usually adopted. For example, the invention patent application with the application announcement number CN111270277A discloses a blind hole filling electroplating process and the plated parts, applications of plated parts, and electronic products obtained by the process; the process uses pulse electroplating to fill the blind holes of the plated parts, or uses a combination of pulse electroplating and direct current electroplating to fill the blind holes of the plated parts. This process can effectively improve the copper plating performance, efficiency and coating distribution. However, the above-mentioned hole filling process has the following shortcomings:

[0004] 1. Blind holes are filled with electroplating technology. In the micro-holes with large depth-to-neck ratio, defects such as holes and clamp filling are prone to occur. On the one hand, the electrical and thermal conductivity of the blind holes are affected. On the other hand, due to the mismatch in the thermal expansion coefficients of copper and plated parts, stress concentration is easily caused, inducing cracks and leading to failure.

[0005] 2. In order to avoid the occurrence of filling defects, a lower current needs to be used during the electroplating process, which greatly reduces the hole filling efficiency. For large-sized blind holes (>10μm), the electroplating copper hole filling efficiency is very low. Summary of the invention

[0006] The purpose of the present invention is to overcome the above-mentioned problems and provide a microvia filling process in an integrated circuit, which can achieve microvia filling with a large depth-to-neck ratio without defects such as hole and clamp filling. In addition, the hole filling efficiency in the process is higher.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A microvia filling process in an integrated circuit comprises the following steps:

[0009] (1) Select metal as the filling material and extend part of the metal into the microholes provided on the substrate;

[0010] (2) Under a controlled atmosphere, the metal is melted and / or melted, and the molten metal fills the micropores through capillary action;

[0011] (3) Polishing the surface of the filled micropores;

[0012] (4) The substrate is subjected to pattern electroplating so that the micropores on the substrate are interconnected to form a circuit layer, thereby obtaining a carrier board with a circuit layer.

[0013] In a preferred embodiment of the present invention, the metal is a metal wire, the metal wire is one, and the diameter of the metal wire is smaller than the diameter of the microhole;

[0014] In step (1), the specific steps of extending a portion of the metal into the microhole provided on the substrate are: extending one end of the metal wire into the microhole;

[0015] In step (2), the metal is melted and / or fused, and the molten metal fills the micropores through capillary phenomenon. The specific steps are: the root of the metal wire exposed outside the micropore is fused, and the molten metal fills the gap between the micropore and the metal wire through capillary phenomenon. By adopting the above steps, the diameter of the metal wire is smaller than the diameter of the micropore, which makes it easy to extend the metal wire into the micropore to fill the micropore; in addition, it can ensure that the partially melted metal wire can be fully filled between the metal wire and the micropore.

[0016] Preferably, the metal is a metal wire, and there are two metal wires, namely a first metal wire and a second metal wire, wherein the first metal wire and the second metal are made of the same material; and the diameter of the first metal wire is smaller than the diameter of the microhole;

[0017] In step (1), the specific steps of extending a portion of the metal into the microhole provided on the substrate are: extending one end of a first metal wire into the microhole, and then leading a second metal wire to be placed above the microhole and close to the root of the first metal wire exposed outside the microhole;

[0018] In step (2), the metal is melted and / or fused, and the molten metal fills the micropores through capillary phenomenon. The specific steps are: the root of the first metal wire exposed outside the micropore is fused, and the second metal wire is melted at the same time, and the molten metal fills the gap between the micropore and the first metal wire through capillary phenomenon. In the above steps, by using two identical metal wires, there is enough metal after melting, thereby ensuring that the molten metal is fully filled between the first metal wire and the micropore.

[0019] Preferably, the metal is a metal wire, and there are two metal wires, namely a first metal wire and a second metal wire, wherein the melting point of the second metal wire is lower than the melting point of the first metal wire; and the diameter of the first metal wire is smaller than the diameter of the microhole;

[0020] In step (1), the specific steps of extending a portion of the metal into the microhole provided on the substrate are: extending one end of a first metal wire into the microhole, and then leading a second metal wire to be placed above the microhole and close to the root of the first metal wire exposed outside the microhole;

[0021] In step (2), the metal is melted and / or melted, and the melted metal fills the micropores through capillary phenomenon. The specific steps are: melt the second metal wire, and the melted metal fills the gap between the micropore and the first metal wire through capillary phenomenon, and then melts the root of the first metal wire exposed outside the micropore, and the melted metal further fills the gap between the micropore and the first metal wire. The above steps can ensure that there is enough metal after melting, so that the melted metal can be fully filled between the first metal wire and the micropore; on the other hand, the melting point of the second metal wire is lower than that of the first metal wire. When filling the micropore, the temperature of the melted metal can be reduced, thereby avoiding damage to the substrate due to high temperature, and at the same time improving the conductive performance.

[0022] Preferably, the metal is a metal wire, the metal wire is one, a metal layer is electroplated on the outside of the metal wire, wherein the diameter of the metal wire is smaller than the diameter of the microhole;

[0023] In step (1), the specific steps of extending a portion of the metal into the micro-holes provided on the substrate are: extending one end of the metal wire plated with the metal layer into the micro-hole;

[0024] In step (2), the metal is melted and / or melted, and the melted metal fills the micropores through capillary phenomenon. The specific steps are: melting the metal layer, and the melted metal fills the gap between the micropore and the metal wire through capillary phenomenon; then melting the root of the metal wire exposed outside the micropore, and the melted metal further fills the gap between the micropore and the first metal wire. The above steps can fully fill the micropores, and the operation is simple and convenient.

[0025] Furthermore, the melting point of the metal layer is lower than that of the metal wire, so that the metal layer can be melted at a relatively low temperature, thereby preventing the substrate from being damaged by high temperature, and the metal wire with a high melting point has good electrical conductivity.

[0026] Preferably, the diameter of the metal wire is 0.7 to 0.95 times the diameter of the microhole, in order to ensure that the metal wire can extend into the microhole while the molten metal can be fully filled in the gap between the metal wire and the microhole.

[0027] Preferably, in step (2), the specific method of melting and / or fusing the metal is: passing a pulse current through the metal or performing laser heating on the metal. Specifically, passing a pulse current through the metal wire or performing laser heating on the metal wire causes the metal wire to fuse with the metal layer, or the metal wire to melt with the metal layer.

[0028] Preferably, the controllable atmosphere comprises one of air, nitrogen, hydrogen, an inert gas or a mixed atmosphere of hydrogen and an inert gas.

[0029] Preferably, the microholes are blind holes and / or through holes.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The micropore filling process of the present invention is to melt and / or fuse the metal, and the molten metal fills the micropores through capillary phenomenon. The filling method is simple and convenient, and can achieve micropore filling with a large depth-to-neck ratio without defects such as hole and clamp filling.

[0032] 2. The micropore filling process of the present invention melts and / or fuses the metal, and the molten metal fills the micropores through capillary phenomenon, which has high filling efficiency, stable structure after filling and better quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The figure is a process flow diagram of a first embodiment of a microvia filling process in an integrated circuit in the present invention.

[0034] Figure 2The figure is a process flow diagram of a second embodiment of a microvia filling process in an integrated circuit in the present invention.

[0035] Figure 3 The figure is a process flow diagram of a third implementation mode of a microvia filling process in an integrated circuit in the present invention.

[0036] Figure 4 The figure is a process flow diagram of a fourth embodiment of a microvia filling process in an integrated circuit in the present invention.

[0037] Figure 5 It is a process flow diagram of a fifth embodiment of a microvia filling process in an integrated circuit in the present invention. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0039] Example 1

[0040] See also Figure 1 This embodiment discloses a microvia filling process in an integrated circuit, comprising the following steps:

[0041] (1) A metal wire 1 is selected as a filling material, and the metal wire 1 is clamped by a wire feeding mechanism 6, and one end of the metal wire 1 is inserted into a microhole 3 provided on a substrate 2, wherein the diameter of the metal wire 1 is 0.7 to 0.95 times the diameter of the microhole 3;

[0042] (2) Under a controlled atmosphere, a laser heating tool 7 is used to perform laser heating on the root of the metal wire 1 exposed outside the microhole 3, so that the metal wire 1 is melted, and part of the melted metal is filled in the gap between the microhole 3 and the metal wire 1 through a capillary phenomenon;

[0043] (3) polishing the surface of the filled micropores 3 by a polishing machine 4;

[0044] (4) The substrate 2 is subjected to pattern electroplating so that the micropores 3 on the substrate 2 are interconnected to form a circuit layer 5, thereby obtaining a carrier board with the circuit layer 5. The carrier board is then passivated and printed with carbon ink.

[0045] See also Figure 1 The micropore filling process in this embodiment melts and / or fuses the metal, and the molten metal fills the micropores 3 through capillary phenomenon. The filling method is simple and convenient, and can achieve the filling of micropores 3 with a large depth-to-neck ratio without defects such as holes and clamp filling. In addition, the filling process has high filling efficiency, a stable structure after filling, and better quality.

[0046] See also Figure 1 In this embodiment, the diameter of the metal wire 1 is smaller than the diameter of the microhole 3, so that the metal wire 1 can be easily inserted into the microhole 3 to fill the microhole 3; in addition, it can ensure that the partially melted metal wire 1 can be fully filled between the metal wire 1 and the microhole 3.

[0047] Specifically, the metal wire 1 is made of copper, silver, gold or platinum. The above metals have good electrical conductivity, so as to improve the performance of the carrier board.

[0048] Specifically, the substrate 2 is made of glass, silicon, ceramic, PI or FR4.

[0049] Specifically, the controllable atmosphere includes air, nitrogen, hydrogen, an inert gas, or a mixed atmosphere of hydrogen and an inert gas.

[0050] See also Figure 1 The microhole 3 is a blind hole and / or a through hole. The microhole 3 in this embodiment is a through hole with a diameter of 20 μm and a depth of 100 μm. A copper wire is selected as the filling material with a diameter of 15 μm.

[0051] Example 2

[0052] See also Figure 2 The micropore filling process disclosed in this embodiment is different from that in Embodiment 1. Specifically, the process includes the following steps:

[0053] (1) Two metal wires 1 of the same material are selected as filling materials, wherein the two metal wires 1 are respectively a first metal wire 1-1 and a second metal wire 1-2, and the first metal wire 1-1 is clamped by a wire feeding mechanism 6, and one end of the first metal wire 1-1 is extended into a microhole 3 provided on a substrate 2, and then the second metal wire 1-2 is led and placed above the microhole 3 and close to the root of the first metal wire 1-1 exposed outside the microhole 3; wherein the diameter of the first metal wire 1-1 is 0.7 to 0.95 times the diameter of the microhole 3;

[0054] (2) Under a controlled atmosphere, the root of the first metal wire 1-1 exposed outside the microhole 3 is laser-heated by the laser heating tool 7, so that the first metal wire 1-1 is melted; at the same time, the second metal wire 1-2 is laser-heated by the laser heating tool 7, so that the second metal wire 1-2 is melted, and the molten metal is filled in the gap between the microhole 3 and the first metal wire 1-1 through capillary phenomenon;

[0055] (3) polishing the surface of the filled micropores 3 by a polishing machine 4;

[0056] (4) The substrate 2 is subjected to pattern electroplating so that the micropores 3 on the substrate 2 are interconnected to form a circuit layer 5, thereby obtaining a carrier board with the circuit layer 5. The carrier board is then passivated and printed with carbon ink.

[0057] See also Figure 2 The micro-hole filling process in this embodiment uses two identical metal wires 1 so that there is enough metal after melting, thereby ensuring that the molten metal is fully filled between the first metal wire 1 and the micro-hole 3.

[0058] See also Figure 2 The metal wire 1 is made of copper, silver, gold or platinum. The above metals have good electrical conductivity, thus improving the performance of the carrier board.

[0059] Specifically, the substrate 2 is made of glass, silicon, ceramic, PI or FR4.

[0060] Specifically, the controllable atmosphere includes air, nitrogen, hydrogen, inert gas, or a mixture of hydrogen and inert gas. The controllable atmosphere in this embodiment is an argon atmosphere.

[0061] See also Figure 2 The microhole 3 is a blind hole and / or a through hole. The microhole 3 in this embodiment is a through hole with a diameter of 30 μm and a depth of 150 μm. Both metal wires 1 are copper wires with a diameter of 25 μm.

[0062] Example 3

[0063] See also Figure 3 The micropore filling process disclosed in this embodiment is different from that in Embodiment 1. Specifically, the process includes the following steps:

[0064] (1) Two metal wires 1 are selected as filling materials, wherein the two metal wires 1 are respectively a first metal wire 1-1 and a second metal wire 1-2, wherein the melting point of the second metal wire 1-1 is lower than that of the first metal wire 1-2, and the first metal wire 1-1 is clamped by a wire feeding mechanism 6, and one end of the first metal wire 1-1 is extended into a microhole 3 provided on a substrate 2, and then the second metal wire 1-2 is led and placed above the microhole 3 and close to the root of the first metal wire 1-1 exposed outside the microhole 3; wherein the diameter of the first metal wire 1-1 is 0.7 to 0.95 times the diameter of the microhole 3;

[0065] (2) Under a controlled atmosphere, the first metal wire 1-1 and the second metal wire 1-2 are simultaneously connected to a pulse power supply 8, and a pulse current with an amplitude of 40A and a pulse width of 1 microsecond is passed through, so that the end of the second metal wire 1-2 contacts the root of the first metal wire 1-1, so that the end of the second metal wire 1-2 melts, and the molten metal fills the gap between the micropore 3 and the first metal wire 1-1 through a capillary phenomenon; then the pulse power supply 8 uses a high-frequency pulse current with an amplitude of 60A to fuse the root of the first metal wire 1-1 exposed outside the micropore 3, and further fills the gap between the micropore 3 and the first metal wire 1-1;

[0066] (3) polishing the surface of the filled micropores 3 by a polishing machine 4;

[0067] (4) The substrate 2 is subjected to pattern electroplating so that the micropores 3 on the substrate 2 are interconnected to form a circuit layer 5, thereby obtaining a carrier board with the circuit layer 5. The carrier board is then passivated and printed with carbon ink.

[0068] See also Figure 3 The micropore filling process in this embodiment can, on the one hand, ensure that there is enough metal after melting, so as to ensure that the molten metal is fully filled between the first metal wire 1 and the micropore 3; on the other hand, the melting point of the second metal wire 1-2 is lower than the melting point of the first metal wire 1. When filling the micropore 3, the temperature of the molten metal can be reduced, thereby avoiding damage to the substrate 2 due to high temperature, and also improving the conductive performance.

[0069] Specifically, the metal wire 1 is made of copper, silver, gold or platinum. The above metals have good electrical conductivity, thus improving the performance of the carrier board.

[0070] Specifically, the substrate 2 is made of glass, silicon, ceramic, PI or FR4.

[0071] Specifically, the controllable atmosphere includes air, nitrogen, hydrogen, inert gas, or a mixture of hydrogen and inert gas. The controllable atmosphere in this embodiment is an argon atmosphere.

[0072] See also Figure 3 The microhole 3 is a blind hole and / or a through hole. The microhole 3 in this embodiment is a through hole with a diameter of 30 μm and a depth of 150 μm. The first metal wire 1-1 is a copper wire, and the second metal wire 1-2 is a tin wire. The diameter of the copper wire is 25 μm.

[0073] Example 4

[0074] See also Figure 4The specific steps in this embodiment are the same as those in Embodiment 3, except that, in step (2), under a controlled atmosphere, the end of the second metal wire 1-2 is laser-heated by a laser heating tool 7, so that the end of the second metal wire 1-2 is melted, and the molten metal is filled in the gap between the micropore 3 and the first metal wire 1-1 through a capillary phenomenon; then, the root of the first metal wire 1-1 exposed outside the micropore 3 is laser-heated by the laser heating tool 7, so that the first metal wire 1-1 is melted, and the molten metal further fills the gap between the micropore 3 and the first metal wire 1-1.

[0075] Example 5

[0076] See also Figure 5 The micropore filling process disclosed in this embodiment is different from that in Embodiment 1. Specifically, the process includes the following steps:

[0077] (1) A metal wire 1 is selected as a filling material. First, a metal layer 9 is electroplated on the metal wire 1. One end of the metal wire 1 plated with the metal layer 9 is inserted into the microhole 3. The diameter of the metal wire 1 is 0.7 to 0.95 times the diameter of the microhole 3. The total diameter of the metal wire 1 plated with the metal layer 9 is 0.9 to 1.2 times the diameter of the microhole 3.

[0078] (2) In a controlled atmosphere, the metal layer 9 is heated by a laser heating tool 7, or the metal wire 1 is connected to a pulse power supply 8 to pass a pulse current through the metal wire 1, so that the metal layer 9 outside the metal wire 1 is melted, and the molten metal is filled in the gap between the micropore 3 and the metal wire 1 through a capillary phenomenon; then the root of the metal wire 1 exposed outside the micropore 3 is cut off by mechanical cutting, laser cutting, laser heating or electric pulse fusing;

[0079] (3) polishing the surface of the filled micropores 3 by a polishing machine 4;

[0080] (4) The substrate 2 is subjected to pattern electroplating so that the micropores 3 on the substrate 2 are interconnected to form a circuit layer 5, thereby obtaining a carrier board with the circuit layer 5. The carrier board is then passivated and printed with carbon ink.

[0081] The micropore filling process in this embodiment can fully fill the micropores 3 and is simple and convenient to operate.

[0082] Specifically, the melting point of the metal layer 9 is lower than the melting point of the metal wire 1. The purpose is to melt the metal layer 9 at a relatively low temperature, thereby preventing the substrate 2 from being damaged by high temperature, and at the same time, the metal wire 1 with a high melting point has good electrical conductivity.

[0083] See also Figure 5In this embodiment, the metal wire 1 is cut by the shearing mechanism 10. The above method is simple to operate and will not be affected by temperature compared to laser heating, thus ensuring that the substrate 2 will not be damaged.

[0084] Specifically, the metal wire 1 is made of copper, silver, gold or platinum. The above metals have good electrical conductivity, thus improving the performance of the carrier board.

[0085] Specifically, the substrate 2 is made of glass, silicon, ceramic, PI or FR4.

[0086] Specifically, the controllable atmosphere includes air, nitrogen, hydrogen, inert gas, or a mixture of hydrogen and inert gas. The controllable atmosphere in this embodiment is a nitrogen atmosphere.

[0087] See also Figure 5 , the micropore 3 is a blind hole and / or a through hole. The micropore 3 in this embodiment is a through hole with a diameter of 30 μm and a depth of 150 μm, the metal wire 1 is a copper wire, and the metal layer 9 is a tin layer. The diameter of the copper wire is 25 μm, and the total diameter of the copper wire wrapped with the tin layer is 30 μm.

[0088] The above is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited to the above content. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A microvia filling process in an integrated circuit, characterized in that: The following steps are involved: (1) Select metal as the filling material and extend part of the metal into the microholes provided on the substrate; (2) In a controlled atmosphere, the metal is melted and melted, and the molten metal fills the micropores through capillary action; (3) Polishing the surface of the filled micropores; (4) Patterning the substrate with electroplating to interconnect the micropores on the substrate to form a circuit layer, thereby obtaining a carrier with a circuit layer; The metal is a metal wire, and there are two metal wires, namely a first metal wire and a second metal wire, wherein the first metal wire and the second metal wire are made of the same material; and the diameter of the first metal wire is smaller than the diameter of the microhole; In step (1), the specific steps of extending a portion of the metal into the microhole provided on the substrate are: extending one end of a first metal wire into the microhole, and then leading a second metal wire to be placed above the microhole and close to the root of the first metal wire exposed outside the microhole; In step (2), the metal is melted and cut, and the molten metal fills the micropores by capillary phenomenon. The specific steps are: cutting off the root of the first metal wire exposed outside the micropores, and melting the second metal wire at the same time, and the molten metal fills the gap between the micropores and the first metal wire by capillary phenomenon.

2. A microvia filling process in an integrated circuit according to claim 1, characterized in that: The diameter of the metal wire is 0.7 to 0.95 times the diameter of the microhole.

3. The microvia filling process in an integrated circuit according to claim 1, characterized in that: In step (2), the specific method of melting and fusing the metal is: passing a pulse current through the metal or performing laser heating on the metal.

4. The microvia filling process in an integrated circuit according to claim 1, characterized in that: The controllable atmosphere includes one of air, nitrogen, hydrogen, an inert gas or a mixed atmosphere of hydrogen and an inert gas.

5. The microvia filling process in an integrated circuit according to claim 1, characterized in that: The micro-holes are blind holes and / or through holes.

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