TWI571891B - Thin film resistor method - Google Patents

Description

Thin film resistor manufacturing method

The invention relates to a method for manufacturing a thin film resistor, in particular to a method for manufacturing a thin film resistor which can be provided with an inorganic protective layer on a thin film resistive layer to improve the reliability of the element.

Please refer to Figure 6(A)~6(D) for a schematic diagram of the manufacturing process of a conventional thin film resistor. First, the upper electrode 102 and the lower electrode 103 are respectively formed on the upper and lower surfaces of the substrate 101, and a mask layer 104 is overlaid on the upper electrode 102. As shown in FIG. 6(B), a film-shaped resistive layer 105 is completely covered on the surface of the substrate 101, the upper electrode 102, and the mask layer 104; by removing the mask layer 104 covering the upper electrode 102. Since the thickness of the resistive layer 105 is extremely thin, the mask layer 104 can be simultaneously removed together with the resistive layer 105 above it, and the removed structure is as shown in FIG. 6(C).

Referring to FIG. 6(D) again, the resistive layer 105 is subjected to etching trimming by an energy beam ablation method, such as a laser beam, a focused ion beam, or the like, so that the resistive layer 105 has a predetermined resistance value. After the resistance layer 105 is etched, the resistive layer 105 is covered with a protective layer 106 as shown in FIG. 6(E). Next, a procedure for separating the thin film resistors is performed along the position indicated by the broken line, and then a further subsequent processing operation is performed to coat the upper electrode 102 and the lower electrode 103 with a plurality of layers of conductive material to form electrodes for soldering.

However, in the structure of the above-mentioned thin film resistor, only the protective layer 106 of a single layer is used to provide protection to the resistive layer 105, and the protective effect can be provided. The resistive layer 105 is susceptible to external environmental factors and causes a large resistance value. The offset of the amplitude changes, deviating from its preset resistance value, and thus the reliability of the product of the thin film resistor is relatively low.

In view of the fact that the existing thin film resistor can only provide a single layer protection for the thin film resistive layer, and the resistance value is susceptible to external factors and cause large errors, the main object of the present invention is to provide a thin film which can improve the stability of the resistance value. Resist method.

In order to achieve the foregoing objective, the method for manufacturing a thin film resistor includes: forming an upper electrode on an upper surface of an insulating substrate; forming a resistive layer on an upper surface of the substrate; and covering the resistive layer with a mask layer, The mask layer has a predetermined pattern to expose a portion of the resistive layer; an inorganic protective layer is completely covered on the mask layer and the exposed resistive layer; and the mask layer is removed to be located on the mask layer The inorganic protective layer is removed together, wherein the unremoved inorganic protective layer is overlaid on the originally exposed resistive layer; the resistive layer is etched by using the inorganic protective layer as an etch mask to remove inorganic protection a layer of resistive layer; forming an organic protective layer, completely covering an organic protective layer on the inorganic protective layer.

Therefore, in addition to the organic protective layer, the present invention further covers an inorganic protective layer, provides double-layer protection for the resistive layer, improves the resistance of the resistive layer against external factors, and reduces resistance. The magnitude of the value change makes the product more reliable.

10‧‧‧Substrate

11‧‧‧Upper electrode

12‧‧‧ lower electrode

13‧‧‧resistance layer

14‧‧‧ mask layer

15‧‧‧Inorganic protective layer

16‧‧‧Organic protective layer

101‧‧‧Substrate

102‧‧‧Upper electrode

103‧‧‧ lower electrode

104‧‧‧mask layer

105‧‧‧resistance layer

106‧‧‧Protective layer

1(A) to 1(H) are schematic cross-sectional views showing the process of the thin film resistor of the present invention.

Fig. 2 is a plan view corresponding to Fig. 1(C) of the present invention.

Figure 3 is a plan view corresponding to Figure 1 (E) of the present invention.

Figure 4 is a plan view of the present invention corresponding to Figure 1 (G).

Figure 5 is a plan view corresponding to Figure 1 (H) of the present invention.

Fig. 6(A) to Fig. 6(E) are schematic cross-sectional views showing the process of a thin film resistor.

As shown in FIG. 1(A), the method of manufacturing the thin film resistor of the present invention first provides an insulating substrate 10, and then directly forms a conductor layer pattern as the upper electrode 11 on the upper surface of the substrate 10; The lower surface further directly forms a conductor layer pattern of the lower electrode 12.

As shown in FIG. 1(B), a thin film is deposited on the upper surface of the substrate 10 to form a resistive layer 13 which completely covers the upper electrode 11, for example, heat assisted evaporation, electron beam assisted evaporation, and chemistry. The resistance layer is formed by a vapor deposition method (CVD), a sol-gel method, a plasma enhanced chemical vapor deposition (PECVD) method, or a physical vapor deposition (PVD) sputtering method. As shown in FIG. 1(C) and FIG. 2, a mask layer 14 having a predetermined pattern is overlying the resistive layer 13. In a preferred embodiment, the mask layer 14 is printed by screen printing. An organic mask layer is formed on the resistive layer 13.

The mask layer 14 mainly shields the resistive layer 13 corresponding to a portion of the upper electrode 11 but still exposes most of the resistive layer 13 formed on the surface of the substrate 10.

As shown in FIG. 1(D), an inorganic protective layer 15 is integrally covered on the resistive layer 13 and the mask layer 14. The inorganic protective layer 15 can be vacuum-coated, thermally assisted, e-beam assisted, and electron-assisted evaporation. It is formed by a vapor deposition method (CVD), a sol-gel method, a plasma enhanced chemical vapor deposition (PECVD) method, or a physical vapor deposition (PVD) sputtering method.

As shown in FIG. 1(E) and FIG. 3, after the inorganic protective layer 15 is formed, the mask layer 14 is removed. While the mask layer 14 is removed, the inorganic protective layer 15 above the mask layer 14 is removed together, and a portion of the resistive layer 13 and the inorganic protective layer 15 retaining a predetermined pattern are exposed. The mask layer 14 of the organic material can be removed by immersion solution or solution rinsing, and the inorganic protective layer 15 above the mask layer 14 is removed.

As shown in FIG. 1(F), the resistive layer 13 is etched by using the inorganic protective layer 15 remaining on the substrate 10 as a mask, so that the resistive layer 13 not covered by the inorganic protective layer 15 is etched and removed. The upper electrode 11 is exposed.

As shown in FIG. 1(G) and FIG. 4, after the unnecessary resistive layer 13 is removed, the resistive layer 13 remaining on the substrate 10 is further trimmed. In the preferred embodiment, an energy beam can be utilized, for example. Techniques such as laser beam, focused ion beam, and focused electron beam are trimmed to obtain the desired resistance value.

As shown in FIG. 1(H) and FIG. 5, after finishing the trimming operation on the resistive layer 13, an inorganic protective layer 16 is overlaid on the inorganic protective layer 15, and the inorganic protective layer 15 and the resistive layer 13 are completely covered. And a partial upper electrode 11. Wherein, the material of the inorganic protective layer 15 may be selected from metal oxides, semiconductor oxides or semiconductor nitrides, such as aluminum oxide (Al ₂ O ₃ ), cerium oxide (SiO ₂ ), tantalum nitride (Si ₃ N _{4 )} The material of the organic protective layer 16 may be an epoxy sealing material. Next, the process of separating the thin film resistors is performed along the position indicated by the broken line, and then performing further subsequent processing operations, so that the conductive material covers the upper electrode 102 and the lower electrode 103 for soldering in practical applications, and this subsequent processing operation is not The features of the invention are not described in detail.

The present invention utilizes the above process to provide at least the following advantages:

1. In the present invention, the inorganic protective layer 15 is covered on the resistive layer 13 in a non-photolithographic manner, and the organic protective layer 16 is provided to provide a double layer of protection for the resistive layer 13, so that the resistive layer 13 can be more difficult. The external resistance (such as temperature, moisture, etc.) changes the resistance value, so the reliability of the thin film resistor product can be improved.

2. When the resistive layer 13 is etched, the inorganic protective layer 15 is directly used as an etch mask, and the mask is not particularly required to be formed by a photoresist layer. After the resistive layer 13 is etched, the inorganic protective layer is not required to be specifically removed, and the process steps can be reduced.

10‧‧‧Substrate

11‧‧‧Upper electrode

12‧‧‧ lower electrode

13‧‧‧resistance layer

15‧‧‧Inorganic protective layer

16‧‧‧Organic protective layer

Claims (9)

A method of manufacturing a thin film resistor, comprising: directly forming an upper electrode on an upper surface of an insulating substrate; forming a resistive layer on the upper surface of the substrate, and the resistive layer covers the upper electrode; corresponding to Positioning the upper electrode, the resistive layer is covered with a mask layer having a predetermined pattern to expose a portion of the resistive layer; the inorganic protective layer is completely covered on the mask layer and the exposed resistive layer Removing the mask layer, and removing the inorganic protective layer on the mask layer, wherein the unprotected inorganic protective layer covers the originally exposed resistive layer; etching the resistive layer The inorganic protective layer is used as an etch mask to remove the resistive layer not covered by the inorganic protective layer; and the organic protective layer is formed on the inorganic protective layer to completely cover an organic protective layer. The thin film resistor manufacturing method of claim 1, wherein between the step of etching the resistive layer and the step of forming the organic protective layer, the method further comprises: trimming the resistive layer so that the resistive layer has a predetermined resistance value. The thin film resistor manufacturing method according to claim 1 or 2, wherein a lower electrode is formed on a lower surface of the substrate. The thin film resistor manufacturing method according to claim 3, wherein the inorganic protective layer is formed by vacuum plating. The thin film resistor manufacturing method according to claim 3, wherein the inorganic protective layer is thermally assisted evaporation, electron beam assisted evaporation, chemical vapor deposition (CVD), sol-gel, Formed by plasma enhanced chemical vapor deposition (PECVD) or physical vapor deposition (PVD) sputtering. The thin film resistor manufacturing method according to claim 3, wherein the resistive layer is formed on the substrate by a thin film deposition method. The thin film resistor manufacturing method according to claim 6, wherein the thin film deposition method for forming the resistance layer comprises a heat assisted evaporation method, an electron beam assisted evaporation method, a chemical vapor deposition method (CVD), a sol gel (sol- Gel), plasma enhanced chemical vapor deposition (PECVD), or physical vapor deposition (PVD) sputtering. The thin film resistor manufacturing method according to claim 2, wherein in the step of trimming the resistive layer, the resistive layer is trimmed with an energy beam. The thin film resistor manufacturing method according to claim 1, wherein the material of the inorganic protective layer is selected from a metal oxide, a semiconductor oxide or a semiconductor nitride; and the material of the organic protective layer is an epoxy sealing material.