Multi-layer film structure for high-speed optical communication module

Abstract

The utility model provides a multilayer film structure for a high-speed optical communication module, which aims to solve the problem of module miniaturization caused by large volume in the prior art, and comprises a ceramic substrate, a front heating layer, a front insulating layer, a front metallization layer and a back metallization layer, through accurate control of the local metal layer and the local insulating layer, interconnection of multiple layers of thin films is formed, isolation and conduction of different layers are achieved, the product size is effectively reduced, and the multi-layer thin film structure further has high conductivity, good thermal stability and excellent mechanical performance and is suitable for miniaturization design of high-integration-level electronic modules.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of multilayer film structure for high-speed optical communication module. BACKGROUND

[0002] With the development of electronic technology, the requirements of miniaturization and integration are gradually increasing, especially in high-frequency and high-power electronic applications, the demand for small circuit modules is growing. In traditional multilayer ceramic substrate technology, low-temperature co-fired ceramic (LTCC) and high-temperature co-fired ceramic (HTCC) processes are common methods to achieve circuit module integration. LTCC and HTCC stack multiple ceramic substrates together to form a multilayer structure using brushing and sintering processes to isolate and conduct different functional layers. However, LTCC and HTCC technology has obvious drawbacks, mainly manifested in the large volume of ceramic substrates, which limits the application of small electronic products, especially in space-limited electronic modules, cannot meet the increasingly stringent volume and weight requirements.

[0003] Therefore, how to effectively reduce product size to achieve customer module miniaturization is a problem that needs to be solved by those skilled in the art. UTILITY MODEL CONTENT

[0004] The utility model aims to solve the above problems of the prior art and provides a multilayer film structure for high-speed optical communication module, which isolates and conducts different layers in multiple layers and realizes precise control and interconnection of local metal layer and local insulating layer, thereby effectively reducing product size and meeting the miniaturization needs of electronic modules. The specific scheme is as follows:

[0005] A multilayer film structure for high-speed optical communication module, comprising a ceramic substrate, a front heating layer, a front insulating layer, and a front metallization layer, the front heating layer is disposed on the upper surface of the ceramic substrate; the front insulating layer is disposed on the upper surface of the front heating layer; the front metallization layer is disposed on the upper surface of the front insulating layer, the front heating layer includes at least one lower conductive area, the front insulating layer includes at least one opening area, and the front metallization layer includes at least one upper conductive area; the lower conductive area and the opening area are aligned, and the upper conductive area and the opening area are aligned.

[0006] Further, the lower conductive region includes a first conductive area, a second conductive area and a third conductive area, the opening region includes a first opening, a second opening and a third opening, and the upper conductive region includes a fourth conductive area, a fifth conductive area and a sixth conductive area; the first conductive area is aligned with the first opening, the third conductive area is aligned with the first opening, the second conductive area is aligned with the second opening, the fifth conductive area is aligned with the second opening, the third conductive area is aligned with the third opening, and the sixth conductive area is aligned with the third opening. By reserving multiple conductive areas and openings, some non-insulated areas are reserved for testing. If the entire area is covered with an insulating layer, the probe test cannot be conducted.

[0007] Further, the area of the first conductive area is larger than that of the second conductive area and the third conductive area, the area of the fourth conductive area is larger than that of the fifth conductive area and the sixth conductive area, and the area of the first opening is larger than that of the second opening and the third opening. The smaller area can be used for probe testing.

[0008] Further, the lower conductive region, the opening region and the upper conductive region are all square in shape.

[0009] Further, it further includes a front gold-tin layer, which is arranged on the upper surface of the front metallization layer. The gold-tin layer adheres to the product and other products, plays a connecting role, and does not affect the effect of the module itself.

[0010] Further, it further includes a back metallization layer, which is arranged on the lower surface of the ceramic substrate. The back is metallized, which can conduct between other products and cooperate with the cutting groove to be insulated.

[0011] Further, the back of the ceramic substrate is provided with a cutting groove, which is used for insulation between two areas. The front of the ceramic substrate is provided with a cutting groove, which is used for insulation with other products when combined. The cutting groove on the front of the ceramic substrate is arranged on the right edge of the ceramic substrate.

[0012] Further, the front heating layer includes an upper titanium layer, an intermediate platinum layer and a lower titanium layer. The upper titanium layer is in contact with the front insulating layer, and the lower titanium layer is in contact with the ceramic substrate. The titanium on both sides enhances the bonding force between the front heating layer and the ceramic substrate, and the titanium on the other side increases the bonding force between the front heating layer and the front insulating layer.

[0013] Further, a seed layer is arranged between the contact surface of the front metallization layer and the front insulating layer. Cr as a seed layer increases the adhesion between the front metallization layer and the front insulating layer.

[0014] Further, the material of the front insulating layer is silicon dioxide, which has higher reliability, insulation resistance and withstand voltage of 1500V.

[0015] Beneficial effects: By designing the conduction area and the opening area, the local metal layer and the insulating layer realize accurate conduction in the area where interconnection is required, without the need for overall metallization treatment on the entire layer, and by realizing conduction and isolation in the local area, the redundancy design between the insulating layer and the conduction layer in the multi-layer structure is effectively reduced, the space utilization of the module is optimized, thereby significantly reducing the overall size of the product; through the accurate interlayer isolation and conduction design, not only the integration of the circuit module is effectively improved, but also the space required by the circuit structure is greatly reduced, meeting the growing miniaturization demand of electronic modules. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a structure diagram of a front heating layer of a multi-layer film structure of a high-speed optical communication module;

[0017] Figure 2 is a structure diagram of a front insulating layer of a multi-layer film structure of a high-speed optical communication module;

[0018] Figure 3 is a structure diagram of a front metallization layer of a multi-layer film structure of a high-speed optical communication module;

[0019] Figure 4 is a structure diagram of a back metallization layer of a multi-layer film structure of a high-speed optical communication module;

[0020] Figure 5 is a structure diagram of a gold-tin layer of a multi-layer film structure of a high-speed optical communication module;

[0021] Figure 6 is a structure diagram of a front cutting groove of a multi-layer film structure of a high-speed optical communication module;

[0022] Figure 7 is a structure diagram of a side overlapping structure of a multi-layer film structure of a high-speed optical communication module;

[0023] In the figure: 100, ceramic substrate, 200, front heating layer, 210, lower conduction area, 220, first conduction area, 230, second conduction area, 240, third conduction area, 300, front insulating layer, 310, opening area, 320, first opening area, 330, second opening area, 340, third opening area, 400, front metallization layer, 410, upper conduction area, 420, fourth conduction area, 430, fifth conduction area, 440, sixth conduction area, 500, front gold-tin layer, 600, back metallization layer, 700, cutting groove. DETAILED DESCRIPTION

[0024] In order to deepen the understanding of the utility model, the utility model will be further described below in combination with examples and drawings, and the examples are only used to explain the utility model and do not constitute a limitation on the protection scope of the utility model.

[0025] Please refer to Figures 1-7 A multilayer film structure for high-speed optical communication module, comprising a ceramic substrate 100, a front heating layer 200, a front insulating layer 300 and a front metallization layer 400, the front heating layer 200 is arranged on the upper surface of the ceramic substrate 100; the front insulating layer 300 is arranged on the upper surface of the front heating layer 200; the front metallization layer 400 is arranged on the upper surface of the front insulating layer 300, the front heating layer 200 comprises at least one lower conductive area 210, the front insulating layer 300 comprises at least one opening area 310, and the front metallization layer 400 comprises at least one upper conductive area 410; the lower conductive area 210 and the opening area 310 are aligned, and the upper conductive area 410 and the opening area 310 are aligned.

[0026] The lower conductive area 210 comprises a first conductive area 220, a second conductive area 230 and a third conductive area 240, the opening area 310 comprises a first opening 320, a second opening 330 and a third opening 340, and the upper conductive area 410 comprises a fourth conductive area 420, a fifth conductive area 430 and a sixth conductive area 440; the first conductive area 220 and the first opening 320 are aligned, the third conductive area 240 and the first opening 320 are aligned, the second conductive area 230 and the second opening 330 are aligned, the fifth conductive area 430 and the second opening 330 are aligned, the third conductive area 240 and the third opening 340 are aligned, and the sixth conductive area 440 and the third opening 340 are aligned; the area of the first conductive area 220 is greater than that of the second conductive area 230 and the third conductive area 240, the area of the fourth conductive area 420 is greater than that of the fifth conductive area 430 and the sixth conductive area 440, and the area of the first opening 320 is greater than that of the second opening 330 and the third opening 340; the shapes of the lower conductive area 210, the opening area 310 and the upper conductive area 410 are all square; further comprising a front gold-tin layer 500, the front gold-tin layer 500 is arranged on the upper surface of the front metallization layer 400; further comprising a back metallization layer 600, the back metallization layer 600 is arranged on the lower surface of the ceramic substrate 100; the back surface of the ceramic substrate 100 is provided with a cutting groove 700, the front surface of the ceramic substrate 100 is provided with a cutting groove 700, and the cutting groove 700 on the front surface of the ceramic substrate 100 is arranged on the right side edge of the ceramic substrate 100; the front heating layer 200 comprises an upper titanium layer, an intermediate platinum layer and a lower titanium layer, the upper titanium layer is in contact with the front insulating layer 300, and the lower titanium layer is in contact with the ceramic substrate 100; a seed layer is arranged between the contact surface of the front metallization layer 400 and the front insulating layer 300; the material of the front insulating layer 300 is silicon dioxide.

[0027] In a specific embodiment, the ceramic substrate 100 is made of aluminum nitride material, which has high thermal conductivity and excellent mechanical properties, and the surface roughness Ra of the substrate is 0.02-0.03 μm, which ensures the smoothness of the surface to adapt to subsequent processes.

[0028] In a specific embodiment, the front heating layer 200 is composed of three layers of metal film, in order of titanium, platinum and titanium, wherein the thickness of the titanium layer is 0.1 μm, with an allowable error range of ± 20%, for enhancing the bonding force with the ceramic substrate 100 and the front insulating layer 300; the thickness of the platinum layer is 0.2 μm, with an error range of ± 10%, and provides electrical conductivity; the surface sheet resistance of the front heating layer 200 is 250 ± 10%, and the corresponding sheet resistance value is 0.8722 ohm, which controls the electrical conductivity of the front heating layer 200 through the sheet resistance to meet the heating requirements in actual use.

[0029] In a specific embodiment, the front insulating layer 300 is deposited by PECVD process, and the material is silicon dioxide with a thickness of 2 μm and an error range of ± 20%, which is used to isolate the heating layer and the front metallization layer 400, and provides electrical insulation function to ensure the mutual isolation of each conductive layer in the multi-layer structure.

[0030] In a specific embodiment, the front metallization layer 400 is composed of chromium, platinum and gold in order, the Cr layer as a seed layer, with a thickness of 0.05 μm and an error of ± 0.02 μm, for enhancing the adhesion with the insulating layer; the Pt layer has a thickness of 0.2 μm and an error of ± 20%, which provides electrical conductivity; the Au layer has a thickness of 1.2 μm and an error of ± 20%, which improves the electrical conductivity and corrosion resistance, and the metallization layer forms a local conduction area through photolithography pattern to ensure the electrical interconnection between circuits.

[0031] In a specific embodiment, the back metallization layer 600 of the ceramic substrate 100 is composed of titanium, platinum and gold in order, the Ti layer has a thickness of 0.03 μm and an error of ± 20%; the Pt layer has a thickness of 0.1 μm and an error of ± 20%; the Au layer has a thickness of 0.3 μm and an error of ± 20%, which is used for electrical connection on the back of the circuit module, and is gold plated in specific resistance areas to ensure its excellent electrical conductivity.

[0032] In a specific embodiment, the front gold-tin layer 500 is used to realize the connection of the product with other electronic components, and the materials used include titanium, platinum, gold, and gold-tin (Au75wt% / Sn25wt%) alloy, with thicknesses of 0.1 μm for the Ti layer, 0.2 μm for the Pt layer, 1.2 μm for the Au layer, 0.5 μm for the Pt layer, 3.5 μm for the AuSn alloy layer, and 0.02 μm for the Au cover layer, with an error range of ±20%, which is used for bonding with other electronic components, and through the design of the multi-layer metal material, the electrical conductivity and connection stability are ensured, and the heat resistance and corrosion resistance requirements are met.

[0033] Through the design of the above multi-layer film structure, the resistance value between the individual pads and the traces is greater than 10 6 ohms, which ensures good electrical insulation effect, the overall collapse edge is controlled to be <30 μm, and the mechanical integrity and reliability of the device are ensured.

[0034] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting, and although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the purpose and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A multilayer thin-film structure for high-speed optical communication modules, characterized in that, The device includes a ceramic substrate, a front heating layer, a front insulating layer, and a front metallization layer. The front heating layer is disposed on the upper surface of the ceramic substrate; the front insulating layer is disposed on the upper surface of the front heating layer; the front metallization layer is disposed on the upper surface of the front insulating layer; the front heating layer includes at least one lower conductive region; the front insulating layer includes at least one opening region; and the front metallization layer includes at least one upper conductive region. The lower conductive region and the opening region are aligned, and the upper conductive region and the opening region are aligned.

2. The multilayer thin-film structure for a high-speed optical communication module according to claim 1, characterized in that... The lower conductive region includes a first conductive region, a second conductive region, and a third conductive region; the opening region includes a first opening, a second opening, and a third opening; and the upper conductive region includes a fourth conductive region, a fifth conductive region, and a sixth conductive region. The first conductive region and the first opening are aligned, the third conductive region and the first opening are aligned, the second conductive region and the second opening are aligned, the fifth conductive region and the second opening are aligned, the third conductive region and the third opening are aligned, and the sixth conductive region and the third opening are aligned.

3. The multilayer thin-film structure for a high-speed optical communication module according to claim 2, characterized in that, The area of ​​the first conductive region is larger than that of the second and third conductive regions, the area of ​​the fourth conductive region is larger than that of the fifth and sixth conductive regions, and the area of ​​the first opening is larger than that of the second and third openings.

4. The multilayer thin-film structure for a high-speed optical communication module according to claim 3, characterized in that, The lower conductive region, the opening region, and the upper conductive region are all square in shape.

5. A multilayer thin-film structure for a high-speed optical communication module according to claim 1, characterized in that, It also includes a front gold-tin layer, which is disposed on the upper surface of the front metallization layer.

6. The multilayer thin-film structure for a high-speed optical communication module according to claim 1, characterized in that, It also includes a back metallization layer, which is disposed on the lower surface of the ceramic substrate.

7. A multilayer thin-film structure for a high-speed optical communication module according to claim 1, characterized in that, The ceramic substrate has a cutting groove on its back side and a cutting groove on its front side, with the cutting groove on the front side of the ceramic substrate located on the right edge of the ceramic substrate.

8. A multilayer thin-film structure for a high-speed optical communication module according to claim 1, characterized in that, The front heating layer includes an upper titanium layer, an intermediate platinum layer, and a lower titanium layer. The upper titanium layer is in contact with the front insulating layer, and the lower titanium layer is in contact with the ceramic substrate.

9. A multilayer thin-film structure for a high-speed optical communication module according to claim 1, characterized in that, A seed layer is provided between the contact surfaces of the front metallization layer and the front insulation layer.

10. A multilayer thin-film structure for a high-speed optical communication module according to claim 1, characterized in that, The material of the front insulating layer is silicon dioxide.

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