Substrate with solder resist structure and method of manufacturing the same, thermoelectric module

Abstract

The application discloses a substrate with a solder resist structure, a preparation method of the substrate and a thermoelectric module. The substrate comprises a substrate plate, the top surface of the substrate plate is provided with a lead flow guide sheet, the lead flow guide sheet is divided into a particle soldering area and a lead soldering area, and a solder resist area is arranged between the particle soldering area and the lead soldering area. The solder resist area has a solder resist structure, the solder resist structure separates the particle soldering area and the lead soldering area, the lead flow guide sheet is composed of a plurality of metal layers stacked together, at least one metal layer in the plurality of metal layers located in the solder resist area has a different thickness structure, the surface of the lead flow guide sheet is uneven to form the solder resist structure, and the different thickness structure is formed by changing the thickness of the metal layer. The solder resist structure is formed by the different thickness structure of the metal layer, the surface of the lead flow guide sheet is continuous, the solder resist effect can be achieved without damaging the lead flow guide sheet, the service life of the product is prolonged, the product quality is improved, the process is simple, and the production cost is low.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor refrigeration, and in particular to a substrate with a solder resist structure, a preparation method thereof and a thermoelectric module. BACKGROUND

[0002] A semiconductor thermoelectric device is usually composed of a lower substrate, an upper substrate and a PN couple (i.e. particles) arranged between the upper and lower substrates. A lead wire is welded at a lead wire welding area of the lower substrate to facilitate the connection of the semiconductor thermoelectric device with an external circuit.

[0003] Since the lead wire welding area and the particle welding area of the semiconductor thermoelectric device are usually located on the same lead flow sheet, the distance between them is short. When soldering, the solder applied on the particle welding area tends to overflow and flow to the lead wire welding area, thereby causing a short circuit problem and resulting in product rejection.

[0004] In the prior art, a solder resist groove is usually formed by complete cutting, i.e. a through cutting is made between the lead wire welding area and the particle welding area to achieve solder blocking. However, in this solder resist method, due to the error of the processing technology, such as uneven thickness of the substrate or inclination of the substrate during cutting, the metal layer of the lead flow sheet (the lead flow sheet is a metal plating layer with small thickness) is easily cut through, resulting in a disconnection between the lead wire welding area and the particle welding area and product rejection.

[0005] In addition, the method of cutting the lead flow sheet to form a solder resist groove will expose the metal layer at the cutting position, resulting in a reduction in the oxidation resistance of the product and affecting the service life of the product. At the same time, additional cutting equipment and corresponding workers need to be added on the production line, resulting in high production cost. SUMMARY

[0006] The first object of the present application is to provide a substrate with a solder resist structure. The solder resist structure is formed by the different thickness of the metal layer, so that the surface of the lead flow sheet is continuous, and the solder resist effect can be achieved without damaging the lead flow sheet, thereby improving the service life and quality of the product.

[0007] The second object of the present application is to provide a preparation method of a substrate with a solder resist structure. The solder resist structure can be obtained by increasing the operation of preparing the metal layer once based on the same preparation conditions and raw materials during the preparation of the metal layer, which is simple in process and low in production cost.

[0008] The third object of the present application is to provide a thermoelectric module using the above-mentioned substrate with a solder resist structure, thereby improving the quality of the product.

[0009] To achieve the above objects, the present application adopts the following technical solutions:

[0010] A substrate with solder resist structure, comprising a substrate plate, a top surface of the substrate plate is provided with a lead flow guide sheet, the lead flow guide sheet is divided into a particle soldering area and a lead soldering area, and a solder resist area is provided between the particle soldering area and the lead soldering area;

[0011] The solder resist area has a solder resist structure for separating the particle soldering area and the lead soldering area;

[0012] The lead flow guide sheet is composed of a plurality of metal layers stacked together, at least one of the plurality of metal layers located in the solder resist area has a different thickness structure, so that the surface of the lead flow guide sheet is uneven to form the solder resist structure, and the different thickness structure is formed by changing the thickness of the metal layer.

[0013] Further, the solder resist structure is a convex structure formed by the protrusion of the lead flow guide sheet;

[0014] Alternatively, the solder resist structure is a concave structure formed by the depression of the lead flow guide sheet.

[0015] Further, the solder resist structure is a long strip structure.

[0016] Further, the solder resist structure penetrates through the solder resist area, and completely separates the particle soldering area and the lead soldering area.

[0017] Further, one of the plurality of metal layers is a copper layer, and the copper layer is located between other metal layers and the substrate plate;

[0018] The different thickness structure is located in the copper layer.

[0019] Further, the plurality of metal layers are a copper layer, a nickel layer and a gold layer arranged from bottom to top;

[0020] The nickel layer and the gold layer at the different thickness structure are both curved to make the surface of the lead flow guide sheet uneven to form the solder resist structure.

[0021] A preparation method of a substrate with solder resist structure, the method is used for preparing the substrate with solder resist structure mentioned above, and the method comprises the following steps:

[0022] The substrate plate is prepared with a metal layer having a different thickness structure, and the metal layer is divided into a base layer and a superimposed layer;

[0023] First, the base layer is prepared on the substrate plate, then part of the area of the base layer is covered with a cover plate, and then the superimposed layer is prepared on the base layer;

[0024] When the metal layer with the uneven thickness structure is not the uppermost metal layer of the lead flow guide sheet, other metal layers are prepared on the metal layer with the uneven thickness structure after the cover plate is removed.

[0025] Further, the cover plate is provided with a strip-shaped cover area corresponding to the solder mask structure.

[0026] Alternatively, the cover plate is provided with a particle solder area cover part and a lead solder area cover part, and a space corresponding to the solder mask structure is arranged between the particle solder area cover part and the lead solder area cover part.

[0027] A thermoelectric module comprising an upper substrate, a lower substrate and a semiconductor element, the semiconductor element being welded between the upper substrate and the lower substrate, the lower substrate being the substrate for semiconductor thermoelectric devices according to any one of claims 1-7;

[0028] The particle solder area is used for soldering the semiconductor thermoelectric device, and the lead solder area is used for soldering a lead.

[0029] Embodiments of the present application can include the following beneficial effects:

[0030] 1. The solder mask structure is formed based on the uneven thickness structure of the lead flow guide sheet, so that the surface of the lead flow guide sheet is not damaged, the lead flow guide sheet maintains good oxidation resistance, and the service life of the product is improved.

[0031] 2. The preparation process of the base layer and the superimposed layer is the same, only after the preparation of the base layer is completed, the cover plate is added again to perform the same process as the preparation of the base layer to complete the preparation of the uneven thickness structure, without increasing other processes and equipment, the solder mask structure can be formed, which not only simplifies the production process but also improves the reliability of the solder mask structure, and there is no situation of product scrap due to processing error. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a top view of a substrate with a solder mask structure according to an embodiment of the present application;

[0033] Figure 2 is a schematic view of a thermoelectric module with a solder mask structure as a protruding structure;

[0034] Figure 3 is a cross-sectional view of a lead flow guide sheet with a solder mask structure as a protruding structure according to an embodiment of the present application;

[0035] Figure 4 is a cross-sectional view of a lead flow guide sheet with a solder mask structure as a protruding structure according to another embodiment of the present application;

[0036] Figure 5is a schematic diagram of a thermoelectric module with a recessed solder resist structure;

[0037] Figure 6 is a schematic diagram of a lead flow sheet with a recessed solder resist structure according to an embodiment of the present application;

[0038] Figure 7 is a schematic diagram of a lead flow sheet with a recessed solder resist structure according to another embodiment of the present application;

[0039] Figure 8 is a schematic diagram of a lead flow sheet metal layer with a protruding solder resist structure;

[0040] Figure 9 is a schematic diagram of a lead flow sheet metal layer with a recessed solder resist structure;

[0041] Figure 10 is a schematic diagram of a cover plate with a recessed solder resist structure;

[0042] Figure 11 is a schematic diagram of a cover plate with a protruding solder resist structure;

[0043] wherein 01 is an upper substrate, 02 is a lower substrate, and 03 is a semiconductor element;

[0044] 1 is a substrate plate, 2 is a lead flow sheet, 21 is a heterogeneous structure, 22 is a copper layer, 23 is a nickel layer, 24 is a gold layer, 201 is a base layer, 202 is a superimposed layer, 3 is a particle soldering area, 4 is a lead soldering area, 5 is a solder resist area, 6 is a solder resist structure, 7 is a cover plate, 71 is a strip-shaped cover area, 72 is a particle soldering area cover portion, 73 is a lead soldering area cover portion, and 74 is a vacant position. DETAILED DESCRIPTION

[0045] Embodiments of the present application are described in detail below with reference to the attached drawings, wherein the same or like reference numerals and characters refer to the same or like components throughout the drawings. The embodiments described below are exemplary only, and are not to be understood as limiting the present application.

[0046] In the description of the present application, it is to be understood by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the features defined with "first", "second" may explicitly or implicitly include one or more of the features, which are used to distinguish the described features, and there is no order or difference.

[0047] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0048] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0049] The following will be described Figures 1 to 11 , a substrate with a solder resist structure and a thermoelectric module and a preparation method thereof.

[0050] The substrate with a solder resist structure according to an embodiment of the present application comprises a substrate plate 1, the top surface of the substrate plate 1 is provided with a lead flow guide sheet 2, the lead flow guide sheet 2 is divided into a particle welding area 3 and a lead welding area 4, and a solder resist area 5 is arranged between the particle welding area 3 and the lead welding area 4;

[0051] The solder resist area 5 has a solder resist structure 6, and the solder resist structure 6 is used to separate the particle welding area 3 and the lead welding area 4;

[0052] The lead flow guide sheet 2 is composed of a plurality of metal layers stacked together, at least one of the plurality of metal layers located in the solder resist area 5 has a different thickness structure 21, so that the surface of the lead flow guide sheet 2 is uneven to form the solder resist structure 6, and the different thickness structure 21 is formed by changing the thickness of the metal layer.

[0053] The thickness of the existing lead flow guide piece on the substrate is uniform, so that the solder resist groove is obtained by adding a cutting process after the preparation of the lead flow guide piece is completed. The solder resist structure of the present application is formed based on the setting of the different thickness structure 21 so that the lead flow guide piece is uneven. This makes the solder resist structure 6 formed without damaging the surface of the lead flow guide piece 2, and the lead flow guide piece 2 maintains good oxidation resistance effect, improving the service life of the product. Moreover, the different thickness structure 21 is located on the metal layer and is formed during the preparation of the metal layer, so that the solder resist structure 6 is obtained at the same time as the preparation of the lead flow guide piece 2 without the need to add additional processes. The forming method of the solder resist structure 6 is more reliable, and there is no situation of product scrap due to processing errors.

[0054] The different thickness structure 21 can be arranged on any one of the metal layers. When a micro TEC (ThermoElectric Cooler) is made, a DPC preparation process, i.e. a direct metal plating method, is used to arrange the lead flow guide piece 2 on the substrate plate 1; when a large TEC is made, a DBC preparation process is used, i.e. the metal copper and the ceramic substrate are firmly and densely bonded together to prepare the substrate. When a certain metal layer has the different thickness structure 21, other metal layers covered thereon are tightly combined with the metal layer, so that the surface of the obtained lead flow guide piece 2 is uneven, and the uneven part corresponds to the different thickness structure 21, i.e. the solder resist structure 6. When the different thickness structure 21 is in the uppermost metal layer of the lead flow guide piece 2, the different thickness structure 21 is equivalent to the solder resist structure. The solder resist structure 6 has a barrier effect on the solder, and eliminates the area short circuit phenomenon caused by the overflow and flow of the solder during the soldering of the lead soldering area or the particle soldering area. Preferably, the solder resist structure 6 penetrates the solder resist area 5, and completely separates the particle soldering area 3 and the lead soldering area 4, achieving a better solder resist effect.

[0055] Specifically, the solder resist structure 6 is a protruding structure formed by the protrusion of the lead flow guide piece 2; or the solder resist structure 6 is a recessed structure formed by the recess of the lead flow guide piece 2. Both the protruding structure and the recessed structure can have a blocking effect on the solder. Specifically, the recessed structure can accommodate the solder, and when the solder flows to the recessed structure, it can fall into the recessed structure, achieving the effect of blocking the solder; the protruding structure can block the flowing solder.

[0056] In some embodiments, the solder resist structure 6 is a strip-shaped structure. When the solder resist structure 6 is a protruding structure, the cross section of the protruding structure is semicircular, rectangular or trapezoidal. When the solder resist structure 6 is a recessed structure, the bottom surface of the recessed structure is arc-shaped or the cross section of the recessed structure is rectangular.

[0057] Preferably, one of the plurality of metal layers is a copper layer 22, and the copper layer 22 is located between the other metal layers and the substrate plate 1; and the different thickness structure 21 is located in the copper layer 22.

[0058] The copper layer 22 is used for semiconductor element 03 or lead welding, the thickness change of the copper layer 22 has substantially negative effect on element welding effect, and the material cost of the copper layer 22 is relatively low compared with other metal layers, and the product cost is not affected by the thickness change of the copper layer 22. The other metal layers are used for conducting electricity or preventing diffusion between two layers, and the thickness change of the other metal layers will affect the conducting effect or the diffusion prevention effect.

[0059] In some embodiments, the plurality of metal layers are copper layer 22, nickel layer 23 and gold layer 24 arranged from bottom to top in sequence; the nickel layer 23 and the gold layer 25 at the uneven thickness structure 21 are both bent to make the surface of the lead flow sheet uneven to form the solder resist structure 6. The nickel layer 23 is used for preventing diffusion between adjacent two metal layers; the gold layer is used for conducting electricity. Preferably, a palladium layer is further arranged between the nickel layer 23 and the gold layer 24 to further improve the effect of preventing diffusion between adjacent two metal layers.

[0060] It should be noted that the lead flow sheet in the embodiment adopts three metal layers, but is not limited to three layers, and other metal layers can be arranged between the metal layers in the embodiment or between the substrate plate and the metal layers. For example, a titanium layer can be further arranged between the substrate plate and the copper layer.

[0061] Correspondingly, the embodiment of the application further provides a preparation method of the substrate with the solder resist structure, which is used for preparing the substrate with the solder resist structure, and the method comprises the following steps:

[0062] The substrate plate 1 is prepared with the metal layer with the uneven thickness structure 21, and the metal layer is divided into a base layer 201 and a superposed layer 202;

[0063] Firstly, the base layer 201 is prepared on the substrate plate 1, then part of the base layer 201 is covered by the cover plate 7, and then the superposed layer 202 is prepared on the base layer 201;

[0064] When the metal layer with the uneven thickness structure 21 is not the uppermost metal layer of the lead flow sheet 2, the cover plate 7 is removed, and other metal layers are prepared on the metal layer with the uneven thickness structure 21.

[0065] The superposed layer 202 covers part of the base layer 201 by the cover plate 7, and when the superposed layer 202 covers the position of the solder resist area corresponding to the base layer 201, the convex structure corresponding to the solder resist area, i.e. the uneven thickness structure 21, is formed. The preparation process of the base layer 201 and the superposed layer 202 is the same, and only the cover plate is added after the preparation of the base layer 201 to perform the same process as the preparation of the base layer 201, so that the preparation of the uneven thickness structure is completed without increasing other processes and equipment, and the solder resist structure is formed, which not only simplifies the production process but also improves the reliability of the solder resist structure.

[0066] When the metal layer with the uneven thickness structure 21 is the uppermost metal layer of the lead flow guide sheet 2, the covering area of the covering plate forms the solder resist structure. When the metal layer with the uneven thickness structure 21 is not the uppermost metal layer of the lead flow guide sheet 2, the covering plate 7 is removed, and other metal layers are prepared on the metal layer with the uneven thickness structure. Based on the existence of the uneven thickness structure 21 and the uniform thickness of the other metal layers, the other metal layers are deformed and bent at the uneven thickness structure 21, so that the top surface of the lead flow guide sheet is uneven and forms the solder resist structure 6.

[0067] When the solder resist structure 6 is a concave structure, the covering plate 7 is provided with a strip-shaped covering area 71 corresponding to the solder resist structure. The strip-shaped covering area 71 covers the solder resist area during the preparation of the superimposed layer 202, so that the thickness of the metal layer in this area is reduced, that is, the thickness of the uneven thickness structure 21 is smaller than that of other areas.

[0068] When the solder resist structure 6 is a convex structure, the covering plate 7 is provided with a particle solder area covering part 72 and a lead solder area covering part 73, and a space 74 corresponding to the solder resist structure 6 is arranged between the particle solder area covering part 72 and the lead solder area covering part 73. The particle solder area covering part 72 and the lead solder area covering part 73 cover the particle solder area and the lead solder area, respectively, and the space 74 corresponds to the solder resist area during the preparation of the superimposed layer 202, so that the thickness of the metal layer in the space 74 is increased, that is, the thickness of the uneven thickness structure 21 is greater than that of other areas.

[0069] Correspondingly, the embodiment of the present application also provides a thermoelectric module, which comprises an upper substrate 01, a lower substrate 02 and a semiconductor element 03, the semiconductor element 03 is welded between the upper substrate 01 and the lower substrate 02, and the lower substrate 02 is the above-mentioned substrate for a semiconductor thermoelectric device;

[0070] The particle solder area 3 is used for welding the semiconductor thermoelectric device 03, and the lead solder area 4 is used for welding the lead.

[0071] Specifically, the bottom surface of the upper substrate 01 is provided with a plurality of flow guide sheets, and the semiconductor element 03 is welded between the flow guide sheet of the upper substrate 01 and the flow guide sheet of the upper substrate 02. The length of the upper substrate 02 is greater than that of the upper substrate 01, so that one end of the upper substrate 02 protrudes out of the upper substrate 01, and the lead flow guide sheet 2 located at the end of the upper substrate 02 also protrudes out of the upper substrate 01, so as to facilitate the welding of the lead on the lead flow guide sheet 2. Based on the design of the solder resist structure 6 on the lead flow guide sheet 2, the solder of the semiconductor element 03 welding area is effectively blocked, and the short circuit phenomenon is prevented, thereby improving the product quality of the semiconductor thermoelectric device.

[0072] Other configurations and operations of the substrate with the solder resist structure, the preparation method thereof and the thermoelectric module according to the embodiment of the present application are known to those skilled in the art, and will not be described in detail here.

[0073] In the description of the specification, reference to the term "embodiment", "example", etc. means that the specific feature, structure, material, or characteristic being described in connection with the embodiment or example is included in at least one embodiment or example of the application. Descriptive terms of the above-mentioned terms do not necessarily refer to the same embodiment or example in the specification. Also, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0074] Although embodiments of the application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and alterations can be made hereto without departing from the principles and the spirit of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. A substrate having a solder resist structure, characterized by, The substrate plate comprises a top surface provided with a lead flow guide fin, the lead flow guide fin is divided into a particle welding area and a lead welding area, and a solder resist area is arranged between the particle welding area and the lead welding area; The solder resist area has a solder resist structure for separating the particle welding area and the lead welding area; The lead flow guide fin is composed of a plurality of metal layers stacked together, at least one of the plurality of metal layers located in the solder resist area has a different thickness structure, which makes the surface of the lead flow guide fin uneven and forms the solder resist structure, and the different thickness structure is formed by changing the thickness of the metal layer; The solder resist structure is a protruding structure formed by the protrusion of the lead flow guide fin; Alternatively, the solder resist structure is a recessed structure formed by the recess of the lead flow guide fin.

2. The substrate with solder resist structure according to claim 1, characterized by, The solder resist structure is a long strip structure.

3. The substrate with solder resist structure according to claim 1, wherein The solder resist structure penetrates through the solder resist area, and the particle welding area and the lead welding area are completely separated.

4. The substrate with solder resist structure according to claim 1, characterized by, One of the plurality of metal layers is a copper layer, which is located between the other metal layers and the substrate plate; The different thickness structure is located in the copper layer.

5. The substrate with solder resist structure according to claim 4, characterized by The plurality of metal layers are a copper layer, a nickel layer and a gold layer arranged from bottom to top; The nickel layer and the gold layer at the different thickness structure are both curved to make the surface of the lead flow guide fin uneven and form the solder resist structure.

6. A method for producing a substrate having a solder resist structure, characterized by, The method is used for preparing the substrate with the solder resist structure according to any one of claims 1-5, and comprises the following steps: The substrate plate is prepared with a metal layer having a different thickness structure, and the metal layer is divided into a base layer and a superimposed layer; First, the base layer is prepared on the substrate plate, then part of the base layer is covered by a cover plate, and then the superimposed layer is prepared on the base layer; When the metal layer with the different thickness structure is not the uppermost metal layer of the lead flow guide fin, after the cover plate is removed, other metal layers are prepared on the metal layer with the different thickness structure.

7. The method of producing a substrate according to claim 6, wherein The cover plate is provided with a strip-shaped covering area corresponding to the solder resist structure; Alternatively, the cover plate is provided with a particle welding area covering part and a lead welding area covering part, and a space corresponding to the solder resist structure is arranged between the particle welding area covering part and the lead welding area covering part.

8. A thermoelectric module characterized by, The substrate plate comprises an upper substrate, a lower substrate and a semiconductor element, the semiconductor element is welded between the upper substrate and the lower substrate, and the lower substrate is the substrate with the solder resist structure according to any one of claims 1-6; The particle welding area is used for welding a semiconductor thermoelectric device, and the lead welding area is used for welding a lead.

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