Appartus and method for soldering

Abstract

A soldering device is disclosed comprising a guide jig disposed on the side of a component to be soldered having a soldering surface, and a flattening jig having a flat surface, wherein the flat surface is disposed spaced apart from the soldering surface of the component to be soldered, thereby forming a cavity formed by the soldering surface, the guide jig, and the flat surface. The soldering device can form a pre-solder layer on the soldering surface by solidifying the molten solder after injecting molten solder into the cavity.

Description

Technology Field

[0001] The present invention relates to a soldering apparatus and method, and more specifically, to a soldering apparatus and method that can flatten the surface of a pre-solder layer created using molten solder to prevent solder from sagging during a subsequent soldering process. Background Technology

[0003] Generally, in the case of a double-sided cooling power module, the semiconductor chip and the substrates placed on the upper and lower sides of the semiconductor are bonded to each other to form an electrical connection. In particular, a component called a spacer is used for the electrical and physical connection between the semiconductor chip and the substrate.

[0004] Spacers establish electrical and physical connections with substrates and semiconductor chips through soldering, which is a process of melting and solidifying solder materials by introducing a preset temperature and gas atmosphere.

[0005] A double-sided cooling power module can be completed by forming one part by soldering some components to the lower substrate and forming the remaining part by soldering the remaining components to the upper substrate, and then stacking the two parts together and performing an additional soldering process. The soldering that forms each part is called primary soldering, and the soldering applied to join the two parts together is called secondary soldering.

[0006] In the first soldering stage, semiconductor chips are typically mounted on the lower substrate, and spacers are mounted on the upper substrate. Additionally, to eliminate the process of inserting separate solder during the second soldering stage, a method is applied in which solder, which is a bonding material, is melted in advance on the exposed surface of the spacer—that is, on a portion of the surface not bonded to the upper substrate—to form a pre-solder layer, and then this pre-solder layer is remelted during the second soldering stage to bond the two parts.

[0007] In this pre-solder layer, the surface exposed by surface tension during solder melting—that is, the surface that does not come into contact with the spacer—is formed in an arch shape. As the exposed surface of the pre-solder layer is formed in an arch shape, uniform contact between the component on the lower substrate and the pre-solder layer during secondary soldering is not achieved, which may cause the molten solder to shift to one side and overflow. This overflow phenomenon increases the risk of electrical short circuits as the solder flows down along the side of the semiconductor chip, and in the opposite area where the solder overflows, the solder adheres, reducing the bonding strength and causing a decrease in the physical and mechanical durability characteristics of the power module.

[0009] The matters described above as background technology are intended only to enhance understanding of the background of the present invention and should not be construed as an acknowledgment that they constitute prior art already known to those skilled in the art. Prior art literature

[0011] KR 10-2017-0092750 AKR 10-2017-0069363 A The problem to be solved

[0012] Accordingly, the present invention aims to solve the technical problem of providing a soldering apparatus and method that can prevent solder drift by flattening the exposed surface of the pre-soldering layer formed using molten solder, thereby ensuring uniformity of the surface where the pre-soldering layer contacts other components during a subsequent soldering process. means of solving the problem

[0014] As a means to solve the above technical problem, the present invention is,

[0015] A guide jig disposed on the side of a soldering target part having a soldering surface; and

[0016] A flattening jig having a flat surface, wherein the flat surface is positioned to be spaced apart from the soldering surface of the component to be soldered, thereby forming a cavity formed by the soldering surface, the guide jig, and the flat surface;

[0017] A soldering device is provided characterized by forming a pre-solder layer on the soldering surface by solidifying the molten solder after injecting molten solder into the cavity.

[0018] In one embodiment of the present invention, the flat surface may be formed parallel to the soldering surface.

[0019] In one embodiment of the present invention, the flattening jig has a protrusion protruding in the direction of the soldering surface, and the flat surface may be formed at the end of the protrusion.

[0020] In one embodiment of the present invention, the guide jig contacts the side of the component to be soldered to form a space extending from the soldering surface, and the protrusion may be inserted into the extended space to form the cavity.

[0021] In one embodiment of the present invention, the soldering target component is a spacer with one end surface soldered to a substrate, and the soldering surface may be the other end surface of the surface soldered to the substrate.

[0023] As another means to solve the above technical problem, the present invention is,

[0024] A step of placing a guide jig on the side of a component to be soldered;

[0025] A step of placing a flattening jig having a flat surface at a position spaced apart from the soldering surface of the above-mentioned soldering target component;

[0026] A step of injecting molten solder into a cavity formed by the soldering surface of the above-mentioned soldering target part, the guide jig, and the flattening jig; and

[0027] A step of solidifying the molten solder to form a pre-solder layer having a flattened exposed surface on the soldering surface;

[0028] A soldering method including is provided.

[0029] In one embodiment of the present invention, the flat surface may be formed parallel to the soldering surface, and the flattening jig may have a protrusion protruding in the direction of the soldering surface, and the flat surface may be formed at the end of the protrusion.

[0030] In one embodiment of the present invention, the guide jig contacts the side of the component to be soldered to form a space extending from the soldering surface, and the step of placing the jig may form the cavity by inserting the protrusion into the extended space.

[0031] In one embodiment of the present invention, the soldering target component is a spacer with one end surface soldered to a substrate, and the soldering surface may be the other end surface of the surface soldered to the substrate.

[0032] In one embodiment of the present invention, the step of joining the soldering target component to the other component by performing soldering while the exposed surface of the pre-solder layer is in contact with the other component may be further included. Effects of the invention

[0034] According to the above soldering apparatus and method, by flattening the exposed surface of the pre-solder layer, the solder overflows or shifts when the pre-solder layer melts, thereby preventing electrical short-circuit failures and suppressing the weakening of physical durability characteristics.

[0036] The effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description below. Brief explanation of the drawing

[0038] FIG. 1 is a cross-sectional view illustrating a soldering device according to one embodiment of the present invention and a component soldered by the same. FIGS. 2 to 6 are cross-sectional views illustrating a soldering method according to an embodiment of the present invention in process order. Specific details for implementing the invention

[0039] Hereinafter, a soldering apparatus and method according to various embodiments of the present invention will be described in detail with reference to the attached drawings.

[0040] FIG. 1 is a cross-sectional view illustrating a soldering device according to one embodiment of the present invention and a component soldered by the same.

[0041] The example illustrated in FIG. 1 explains the case where the soldering target component (10) is a spacer used in a power module. In the following description, the soldering target component (10) may also be described as a spacer, but this does not limit the application to only spacers as the soldering target component (10).

[0042] Referring to FIG. 1, a soldering device according to one embodiment of the present invention may be configured to include a guide jig (100) and a flattening jig (200).

[0043] A guide jig (100) is positioned on the side of a spacer (10), which is a component to be soldered, and can serve to align the spacer (10) in a horizontal direction while simultaneously guiding a specific space on the upper surface (11) of the spacer (10). That is, the guide jig (100) not only fixes the position of the spacer (10) in a lateral direction but also allows a certain space to be formed on the upper surface of the spacer (10). It is preferable that the upper height of the guide jig (100) be formed higher than the upper surface of the spacer (10).

[0044] The flattening jig (200) is positioned on top of the guide jig (100) and may have a flat surface that blocks the space formed on top of the spacer (10) by the guide jig (100) from the top.

[0045] A cavity, which is an empty space, can be formed on the upper part of the spacer (10) by the arrangement of the guide jig (100) and the flattening jig (200). When molten solder is filled into the cavity and solidified, a pre-solder layer (21) can be formed on the upper surface of the spacer (10), i.e., the soldering surface (11).

[0046] Meanwhile, in FIG. 1, the lower surface of the spacer (10) can be soldered to the substrate (30). Reference numeral '22' indicates a solder layer used for joining the spacer (10) and the substrate (30). Additionally, FIG. 1 illustrates an example in which a substrate (30) is used in the form in which metal layers (32, 33) are bonded to the upper and lower surfaces of an insulating layer (31), but the present invention is not limited thereto.

[0047] FIGS. 2 to 6 are cross-sectional views illustrating a soldering method according to an embodiment of the present invention in process order. Through the description of the soldering method carried out with reference to FIGS. 2 to 6, the configuration and operational effects of a soldering device according to various embodiments of the present invention can also be explained more clearly and in detail.

[0048] A soldering method according to one embodiment of the present invention may first begin with the step of preparing a structure in which a spacer (10) and a substrate (30) to be soldered are pre-soldered as shown in FIG. 2.

[0049] A double-sided cooling power module adopts a structure having substrates on the upper and lower surfaces, respectively, and can be manufactured by first producing a first part in which a power semiconductor chip is soldered to one substrate and a second part in which a spacer is soldered to another substrate, and then stacking the first part and the second part together and soldering the spacer and the power semiconductor chip. The process of manufacturing the first part and the second part can be called first soldering, and the process of joining the first part and the second part together can be called second soldering. FIG. 2 illustrates the second part manufactured by first soldering.

[0050] Next, as illustrated in FIG. 3, a guide jig (100) can be placed on the side of the spacer (10). FIG. 3 is a cross-sectional view and is shown as having guide jigs (100) installed on the left and right sides of the drawing, but the guide jig (100) may be placed in a form that surrounds the spacer (10) by engraving the cross-sectional shape of the spacer (10) on the contact surface of the guide jig (100) that contacts the spacer (10). In addition, as another example, an additional guide jig may be placed in the front-rear direction of the drawing.

[0051] As illustrated in FIG. 3, the upper end of the guide jig (100) can be formed at a position higher than the upper surface of the spacer (10), which is the soldering surface (11). By doing so, a space can be formed on the upper surface of the spacer (10) in which the side is guided by the guide jig (100).

[0052] FIGS. 2 and FIGS. 3 illustrate that a guide jig (100) is placed after the spacer (10) and the substrate (30) are joined, but the spacer (10) may be soldered to the substrate (30) after the guide jig (100) is installed.

[0053] Next, as illustrated in FIG. 4, a flattening jig (200) may be placed on the upper surface of the guide jig (100). The flattening jig (200) is placed on the upper surface of the guide jig (100) and can block (cover) the space formed on the upper surface (soldering surface) (11) of the spacer (10) from above. That is, by the arrangement of the guide jig (100) and the flattening jig (200), a cavity (C), which is an empty space, can be formed on the upper surface (11) of the spacer (10).

[0054] In one embodiment of the present invention, the flattening jig (200) may have a protrusion (210) protruding in the direction of the soldering surface (11) of the spacer (10). The lower end of the protrusion (210) may be formed as a flat surface (211) facing the soldering surface (11) of the spacer (10) and parallel to the soldering surface (11) of the spacer (10).

[0055] As described in FIG. 3, an empty space may be formed on the upper part of the spacer (10) by the side of the guide jig (100) extending from the soldering surface (upper surface) of the spacer (10). The protrusion (210) of the flattening jig (200) may be positioned to be inserted into the empty space formed by the soldering surface of the spacer (10) and the side of the guide jig (100).

[0056] The distance between the lower surface (211) of the protrusion (210) of the flattening jig (200) and the soldering surface (upper surface) of the spacer (10) may correspond to the thickness of the pre-soldering layer ('21' in FIG. 1) to be formed. That is, by appropriately determining the length of the protrusion (210) of the flattening jig (200), the height of the pre-soldering layer (21) can be determined as desired.

[0057] Next, molten solder is filled into the cavity (C) formed on the upper soldering surface of the spacer (10) by the arrangement of the guide jig (100) and the flattening jig (200) (as shown in FIG. 1), and after solidifying the molten solder through cooling or the like, the guide jig (100) and the flattening jig (200) are removed, thereby completing the formation of a pre-solder layer (21) on the upper surface of the spacer (10) as shown in FIG. 5. The exposed surface (upper surface) (21a) of the pre-solder layer (21) can be soldered to another part in a subsequent process.

[0058] Next, as illustrated in FIG. 6, during the manufacturing process of the power module, a second part as illustrated in FIG. 5 can be bonded to a first part that has been pre-fabricated in an upside-down state. Here, the first part may include a substrate (60) and a power semiconductor chip (40) bonded to the substrate by solder (50).

[0059] After the first soldering process for producing the first part and the second part, in the second soldering process, the exposed surface (21a) of the pre-solder layer (21) is positioned to contact the upper surface of the power semiconductor chip (40), and a pre-set temperature and gas atmosphere are introduced to melt / solidify the pre-solder layer (21) so as to complete the bonding between the first part and the second part, that is, the physical / electrical bonding between the spacer (10) and the power semiconductor chip (40).

[0060] As illustrated in FIGS. 5 and 6, the exposed surface (21a) of the pre-solder layer (21) formed by the soldering apparatus and method according to an embodiment of the present invention can be completed into a flat shape by a flattening jig (200). That is, while the exposed surface of the pre-solder layer (21) is conventionally formed into a convex arch shape due to surface tension, according to the soldering apparatus and method according to an embodiment of the present invention, the exposed surface of the pre-solder layer (21) can be formed into a flat surface parallel to the surface of the spacer (10) on which the pre-solder layer (21) is formed. Accordingly, when the exposed surface of the pre-solder layer (21) contacts another component for soldering, uniform contact can be made over the entire surface, so even if the pre-solder layer (21) is melted, the problem of the molten solder overflowing to one side or the solder being insufficient on the other side can be resolved.

[0062] Although specific embodiments of the present invention have been illustrated and described above, it will be obvious to those skilled in the art that the present invention can be modified and varied in various ways within the scope of the claims. Explanation of the symbols

[0064] 10: Component to be soldered (spacer) 11: Soldering surface 21: Pre-solder layer 21a: Exposed surface of the pre-solder layer 22: Solder layer 30: Substrate 40: Power semiconductor chip 50: Solder layer 60: Substrate 100: Guide jig 200: Flattening jig 210: Protrusion 211: Flat surface

Claims

Claim 1 A soldering apparatus comprising: a guide jig disposed on the side of a component to be soldered having a soldering surface; and a flattening jig having a flat surface formed parallel to the soldering surface, wherein the flat surface is disposed spaced apart from the soldering surface of the component to be soldered, and a cavity is formed by the soldering surface, the guide jig, and the flat surface; wherein a pre-solder layer is formed on the soldering surface by solidifying the molten solder after injecting molten solder into the cavity. Claim 2 delete Claim 3 A soldering device comprising: a guide jig disposed on the side of a component to be soldered having a soldering surface; and a flattening jig having a flat surface, wherein the flat surface is disposed spaced apart from the soldering surface of the component to be soldered, and a cavity is formed by the soldering surface, the guide jig, and the flat surface; wherein a pre-solder layer is formed on the soldering surface by solidifying the molten solder after injecting molten solder into the cavity, and the flattening jig has a protrusion protruding in the direction of the soldering surface, and the flat surface is formed at the end of the protrusion. Claim 4 A soldering device according to claim 3, wherein the guide jig contacts the side of the component to be soldered to form a space extending from the soldering surface, and the protrusion is inserted into the extended space to form the cavity. Claim 5 A soldering apparatus according to claim 1, wherein the soldering target component is a spacer with one end surface soldered to a substrate, and the soldering surface is the other end surface of the surface soldered to the substrate. Claim 6 A soldering method comprising: a step of placing a guide jig on the side of a component to be soldered; a step of placing a flattening jig having a flat surface formed parallel to the soldering surface at a position spaced apart from the soldering surface of the component to be soldered; a step of injecting molten solder into a cavity formed by the soldering surface of the component to be soldered, the guide jig, and the flattening jig; and a step of solidifying the molten solder to form a pre-solder layer having a flattened exposed surface on the soldering surface. Claim 7 delete Claim 8 A soldering method comprising: a step of placing a guide jig on the side of a component to be soldered; a step of placing a flattening jig having a flat surface at a position spaced apart from the soldering surface of the component to be soldered; a step of injecting molten solder into a cavity formed by the soldering surface of the component to be soldered, the guide jig, and the flattening jig; and a step of solidifying the molten solder to form a pre-solder layer having a flattened exposed surface on the soldering surface; wherein the flattening jig has a protrusion protruding in the direction of the soldering surface, and the flat surface is formed at the end of the protrusion. Claim 9 A soldering method according to claim 8, wherein the guide jig contacts the side of the component to be soldered to form a space extending from the soldering surface, and the step of placing the jig is characterized by inserting the protrusion into the extended space to form the cavity. Claim 10 A soldering method according to claim 6, wherein the soldering target component is a spacer with one end surface soldered to a substrate, and the soldering surface is the other end surface of the surface soldered to the substrate. Claim 11 A soldering method according to claim 6, further comprising the step of performing soldering while the exposed surface of the pre-solder layer is in contact with another component to join the component to be soldered to the other component.

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