Method for manufacturing thin film chip resistor device

A method for manufacturing a thin film chip resistor device includes the steps of: disposing a magnetic fixing member on a first surface of a substrate, and disposing a magnetic shadow mask on a second surface of the substrate opposite to the first surface, such that the magnetic shadow mask detachably and fixedly contacts the second surface of the substrate by virtue of an attractive magnetic force between the magnetic fixing member and the magnetic shadow mask; and depositing at least one resistor unit on the second surface of the substrate with the use of the magnetic shadow mask, the resistor unit including two separated first electrode elements and a resistor element that electrically interconnects the first electrode elements.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese Patent Application No. 104117423, filed on May 29, 2015.

FIELD

The disclosure relates to a method for manufacturing a resistor device, more particularly to a method for manufacturing a thin film chip resistor device.

BACKGROUND

Resistors are used for reducing voltage or limiting current flow. Chip resistor devices can generally be classified into thick film chip resistor devices and thin film chip resistor devices. The thick film chip resistor devices normally have a film thickness larger than 5 μm and are usually made by silk screen printing techniques. The thin film chip resistor devices normally have a film thickness smaller than 1 μm and are usually made by chemical vapor deposition techniques or physical vapor deposition techniques such as vacuum evaporation, magnetron sputtering, etc., in combination with photolithography.

During photolithography, a resistor layer is first formed on a substrate, followed by etching the resistor layer with the use of a patterned photoresist to obtain a chip resistor device with a desired resistor value. However, a developer used in the photolithography process is toxic and may be harmful to equipment operators and the environment. Moreover, the equipment and maintenance costs are rather high.

In an alternative method, a mask with a predetermined pattern is formed on a substrate by screen printing techniques, followed by depositing a resistor layer on the substrate. However, the mask formed by screen printing techniques tends to deform and cause an undesired resistor value shift. Furthermore, the mask must be removed by use of chemicals, which contributes to increased levels of environmental pollution.

SUMMARY

Therefore, an object of the present disclosure is to provide a method for manufacturing a thin film chip resistor device that can alleviate at least one of the aforementioned drawbacks associated with the conventional method.

According to an aspect of the present disclosure, a method for manufacturing a thin film chip resistor device includes the steps of:

disposing a magnetic fixing member on a first surface of a substrate, and disposing a magnetic shadow mask on a second surface of the substrate opposite to the first surface, such that the magnetic shadow mask detachably and fixedly contacts the second surface of the substrate by virtue of an attractive magnetic force between the magnetic fixing member and the magnetic shadow mask; and

depositing at least one resistor unit on the second surface of the substrate with the use of the magnetic shadow mask, the resistor unit including two separated first electrode elements and a resistor element that electrically interconnects the first electrode elements.

DETAILED DESCRIPTION

Before the disclosure is described in further detail with reference to the accompanying embodiments, it should be noted herein that like elements are denoted by the same reference numerals throughout the disclosure.

Referring toFIGS. 1 to 5, a first embodiment of a method for manufacturing multiple thin film chip resistor devices5according to the present disclosure includes a mask disposing step11, a resistor unit depositing step12, a dicing step13and a plated unit forming step14.

Referring toFIG. 2, a substrate21is firstly provided. The substrate21has a first surface211, a second surface212opposite to the first surface211, and a side surface213interconnecting the first and second surfaces211,212. The substrate21is defined with a plurality of first imaginary dicing lines (X) that are separated from one another along a first direction (A), and a plurality of second imaginary dicing lines (Y) that are separated from one another along a second direction (B) and that intersect the first imaginary dicing lines (X) to define a plurality of substrate units22.

Next, in the mask disposing step11, a magnetic fixing member32is disposed on the first surface211of the substrate21, and a first magnetic shadow mask311is disposed on the second surface212of the substrate21, such that the first magnetic shadow mask311detachably and fixedly contacts the second surface212of the substrate21by virtue of the attractive magnetic force between the magnetic fixing member32and the first magnetic shadow mask311. Afterwards, the magnetic fixing member32, the first magnetic shadow mask311and the substrate21are fixed with the fixture unit33.

In the resistor unit depositing step12, at least one resistor unit24is deposited on the second surface212of the substrate21. The resistor unit24includes two separated first electrode elements241and a resistor element242electrically interconnecting the first electrode elements241. In this embodiment, a plurality of resistor units24are deposited on the second surface212. Specifically, as shown inFIGS. 2 and 3, in this embodiment, a plurality of separated resistor strips242′ (to be formed into the resistor elements242of the resistor units24) are formed on the second surface212of the substrate21with the use of the first magnetic shadow mask311. The resistor strips242′ are arranged along the second direction (B) and extend in the first direction (A). Afterwards, the fixture unit33and the first magnetic shadow mask311are removed sequentially.

Next, as shown inFIG. 3, a second magnetic shadow mask312having a pattern different from that of the first magnetic shadow mask311is disposed on the second surface212of the substrate21, such that the second magnetic shadow mask312detachably and fixedly contacts the second surface212of the substrate21by virtue of the attractive magnetic force between the magnetic fixing member32and the second magnetic shadow mask312. Then, the magnetic fixing member32, the second magnetic shadow mask312and the substrate21are fixed with the fixture unit33. Subsequently, a plurality of electrode pads241′ (to be formed into the electrode elements241of the resistor units24) are formed on the resistor strips242′ with the use of the second magnetic shadow mask312so as to form an assembly composed of the substrate21, the resistor strips242′ and the electrode pads241′. The electrode pads241′ are arranged in a matrix form such that a part of the regions of each of the resistor strips242′ are exposed. With such arrangement, each of the substrate units22is formed thereon the resistor unit24containing the two electrode elements241and the resistor element242interconnecting the two electrode elements241. Note that the detailed structure of the resistor units24is well-known in the art and is therefore not further elaborated hereinafter for the sake of brevity.

After the formation of the electrode pads241′, each of the resistor elements242may be cut (i.e., by using laser cutting) to obtain a desired resistor value. The adjustment of the resistor value is well-known in the art and additional elaboration thereof will thus not be provided hereinafter for the sake of brevity. It should be noted that, according to practical requirements, the electrode pads241′ may be formed first, followed by forming the resistor strips242′.

Referring toFIG. 4, before the dicing step13, a step of forming a plurality of protective units25may be conducted so that the resistor units24are covered with the protective units25. Specifically, an exposed surface of each of the resistor elements242may be covered with a respective one of the protective units25.

In the dicing step13, the assembly is first diced along the first imaginary dicing lines (X) and the second imaginary dicing lines (Y) so as to form a plurality of chip resistor semi-products40, each of which includes a respective one of the resistor units24(seeFIG. 4).

Referring toFIG. 5, after the dicing step13, the plated unit forming step14is conducted. In the plated unit forming step14, a plated unit27is formed (e.g., by using a barrel plating technique) on the first electrode elements241of the resistor unit24of a respective one of the chip resistor semi-products40. The plated unit27includes two plated metal laminates271each covering and electrically contacting a respective one of the first electrode elements241. In this embodiment, each of the plated metal laminates271is composed of a nickel metal layer272and a tin metal layer273. Note that the plated metal laminate271may alternatively be a single-layered structure. The plated unit27may protect underlying metal layers from sulfurization, erosion, etc.

Note that each protective unit25protects the resistor element242of a corresponding resistor unit24from collision and contamination in the course of manufacturing. The protective units25may be formed after the resistor unit depositing step12(as mentioned above) or after the dicing step13. In each thin film chip resistor device5, a top surface of the protective unit25is lower than a top surface of the plated unit27, so that the plated metal laminates271of the plated unit27can be in direct and electrical contact with a circuit board (not shown) without structural hindrance.

It should be pointed out that the first and second magnetic shadow masks311,312may be independently made of a magnetic material, e.g., iron, cobalt or nickel. The magnetic fixing member32may be a permanent magnet or a temporary magnet. The shape of the magnetic fixing member32may be changed according to the shapes of the first and second magnetic shadow masks311,312so as to achieve superior attractive magnetic force between the magnetic fixing member32and the first and second magnetic shadow masks311,312. The resistor element242of each of the resistor units24may be made of a material, e.g., nickel-chromium alloy, nickel-chromium-aluminum alloy, nickel-chromium-silicon alloy, chromium-silicon alloy, manganese-copper-nickel alloy, manganese-copper-tin alloy, or manganese-aluminum alloy. The first electrode elements241of each of the resistor units24may be made of a material, e.g., silver, copper or gold. The protective units25may be made of epoxy resin or acrylic resin.

Note that the magnetic fixing member32, the magnetic shadow mask and the substrate21are fixed with the fixture unit33by means of screw locking, interlocking, etc. The fixture unit33is used for increasing deposition precision and may be omitted according to practical requirements.

It should be noted that, in the first embodiment, the dicing step13may be omitted when manufacturing a single thin film chip resistor device5rather than multiple thin film chip resistor devices5.

Referring toFIG. 6, a second embodiment of the method for manufacturing multiple thin film chip resistor devices7according to the present disclosure includes a conducting unit forming step61, a mask disposing step62, a resistor unit depositing step63, a first dicing step64, a connecting unit forming step65, a second dicing step66and a plated unit forming step67.

The substrate used in the second embodiment has a structure identical to that of the first embodiment.

Referring toFIG. 7, in the conducting unit forming step61, a plurality of the conducting units23are disposed on the first surface211of the substrate21. Each of the conducting units23is located within a respective one of the substrate units22and includes two second electrode elements231that are separated from each other in the first direction (A). The conducting units23may be disposed by sputtering technique, evaporation technique, screen printing technique, etc. The second electrode elements231may be made of conductive materials, e.g., silver, copper or nickel-chromium alloy.

The mask disposing step62and the resistor unit depositing step63in the second embodiment are the same as the mask disposing step11and the resistor unit depositing step12in the first embodiment.

In the first dicing step64, the substrate21is diced along the first imaginary dicing lines (X) to form a plurality of substrate blocks (not shown).

Referring toFIG. 9, in the connecting unit forming step65, a plurality of connecting units26are formed on side surfaces of the substrate blocks. The connecting units respectively correspond to the conducting units23and respectively correspond to the resistor units24. Each of the connecting units26includes two connecting elements261, each of which interconnects a respective one of the first electrode elements241of one of the resistor units24to which the connecting unit26corresponds and a respective one of the second electrode elements231of one of the connecting units23to which the connecting unit26corresponds. The connecting units26may be formed by sputtering technique, evaporation technique, etc. The connecting elements261may be made of conductive materials, e.g., silver, copper or nickel-chromium alloy.

In the second dicing step66, the substrate blocks are diced along the second imaginary dicing lines (Y) to form a plurality of chip resistor semi-products40.

The plated unit forming step67in the second embodiment is similar to the plated unit forming step14in the first embodiment except that, in the plated unit forming step67, the plated unit27is formed on a respective one of the chip resistor semi-products40such that each of the plated metal laminates271of the plated unit27covers and electrically contacts a respective one of the first electrode elements241, the respective one of the connecting elements261and the respective one of the second electrode elements231.

Similar to the first embodiment, the second embodiment may also include the step of forming the protective units25. In the second embodiment, based on actual requirements, the step of forming the protective units25may be conducted before the first dicing step64, between the first and second dicing steps64,66, or after the second dicing steps.

Note that either the first electrode elements241or the second electrode elements231of a respective one of the thin film chip resistor devices7can be used for electrically contacting the circuit board via a respective plated unit27. In each thin film chip resistor device7, when the second electrode elements231are used for electrical connection, a top surface of the protective unit25may be higher than a top surface of the plated unit27.

It should be noted that, in the second embodiment, the first and second dicing steps64,66may be omitted when manufacturing a single thin film chip resistor device7rather than multiple thin film chip resistor devices7.

To sum up, with the use of the magnetic fixing member32, and the first and second magnetic shadow masks311,312, the resistor units24can be formed with precise shapes and at precise locations.