CN-122028645-A - Method for improving noise of three-dimensional anisotropic magneto-resistive sensor product and product

Abstract

The application provides a method for improving noise of a three-dimensional anisotropic magneto-resistive sensor product and the product. The method comprises the steps of providing a substrate with a lower metal layer, a dielectric layer and a through hole, designing and forming a top metal layer connected with the lower metal layer through the through hole, wherein a bonding pad area is arranged on the top metal layer, optimizing the layout of the through hole under the bonding pad area, setting the distance between the through holes to be more than 3 microns and the data ratio to be less than 10%, so as to reduce cavities generated when the top metal layer fills the through hole, and forming a passivation protection layer on the top metal layer and opening the bonding pad area. According to the application, through optimizing the layout of the through holes, the void defect of the top metal layer is eliminated, the material residue during development of the passivation layer is avoided, and the contact resistance is reduced, so that the noise performance of the product is remarkably improved and the yield is improved.

Inventors

• WANG RUI
• DAI YOUJIANG
• CHENG WANGYANG
• LI LINGJUN

Assignees

• 上海华虹宏力半导体制造有限公司

Dates

Publication Date

20260512

Application Date

20260127

Claims (9)

1. 1. A method of improving noise in a three-dimensional anisotropic magnetoresistive sensor product, comprising at least: providing a substrate, wherein an interconnection layer is arranged on the substrate, and comprises a lower metal layer, a dielectric layer and a through hole formed in the dielectric layer; designing and forming a top metal layer, wherein the top metal layer is electrically connected with the lower metal layer through the through hole, and a pad area is arranged on the top metal layer; forming a passivation protection layer on the top metal layer, and carrying out opening treatment on the bonding pad area to expose part of the top metal layer for subsequent packaging connection; In the second step, an optimal design is performed on the layout of the through holes below the pad region, wherein the optimal design comprises controlling the distance between the through holes and the distribution density of the through holes in the pad region so as to reduce void defects generated when the top metal layer fills the through holes.
2. 2. The method of claim 1, wherein in the second step, the layout optimization design of the via holes comprises setting a pitch between adjacent via holes within the pad region to be greater than 3 μm.
3. 3. The method for improving noise of three-dimensional anisotropic magneto-resistive sensor product according to claim 1, wherein in the second step, layout optimization design of the via holes specifically comprises controlling a data rate of the via holes inside the pad region to be less than 10%.
4. 4. The method of claim 1, wherein in the second step, the optimization is performed by reducing the number of the through holes in the middle region of the pad region.
5. 5. The method of claim 1, wherein in the second step, the top metal layer is made of at least one material selected from the group consisting of aluminum, copper, aluminum-copper alloy, aluminum-silicon-copper alloy, tungsten, titanium nitride, tantalum, and tantalum nitride.
6. 6. The method of improving noise of a three-dimensional anisotropic magnetoresistive sensor product of claim 5 wherein after step three the method is further used in a wafer level chip scale packaging process comprising forming a rewiring layer and providing solder balls electrically connected to the pad areas through the rewiring layer.
7. 7. The method of claim 6, wherein the passivation layer comprises a polyimide material, and wherein the optimization design is used for avoiding residual polyimide material at void defects caused by the void defects of the top metal layer during development of the passivation layer.
8. 8. The method of claim 1, wherein in the first step, the dielectric layer is an interlayer dielectric layer.
9. 9. An improved three-dimensional anisotropic magnetoresistive sensor product manufactured by the method of any of claims 1 to 8, comprising: A substrate; a lower metal layer located above the substrate; the dielectric layer covers the lower metal layer and is provided with a through hole; The top metal layer is positioned above the dielectric layer and is electrically connected with the lower metal layer through the through hole, and the top metal layer is provided with a bonding pad area; A passivation protection layer partially covering the top metal layer; wherein a pitch of the through holes located under the pad region is greater than 3 micrometers, and a data rate of the through holes located inside the pad region is less than 10%.

Description

Method for improving noise of three-dimensional anisotropic magneto-resistive sensor product and product Technical Field The invention relates to the technical field of semiconductors, in particular to a method for improving noise of a three-dimensional anisotropic magneto-resistive sensor product and the product. Background Microelectromechanical systems (Micro Electro MECHANICAL SYSTEM, MEMS) are Micro integrated systems that utilize integrated circuit technology and micromachining technology to fabricate microstructures, microprocessors, control processing circuitry, and even interface circuitry, communication circuitry, power circuitry, etc., on one or more chips. Among them, a magneto-resistive sensor (such as an anisotropic magneto-resistive sensor, AMR) is used as an important MEMS product, and is widely used in the fields of geomagnetic detection, current detection, and the like. In order to meet the requirements of modern electronic devices for miniaturization, high performance and high reliability, MEMS products are generally packaged by Wafer Level Chip Size Packaging (WLCSP) process, especially by means of ball mounting. The packaging mode has the advantages of small packaging size, low parasitic parameters, high signal quality and the like. The WLCSP process is primarily related to the Polyimide (PI) process and the rewiring layer (RDL) process. In conventional three-dimensional (3D) AMR product design and manufacturing processes, in order to enhance the reliability of the interlayer connection and expand the process window, as many VIAs (VIA) as possible are usually designed under the bonding pad to connect the Top Metal (Top Metal) with the lower Metal (e.g., metal 1). As shown in the conventional process structure of fig. 1, an interlayer dielectric (IMD) is covered on the lower Metal layer (Metal 1), and dense VIA holes (VIA) are formed in the IMD, and the top Metal layer is deposited and fills these VIA holes. However, this conventional design concept causes new problems in the actual process. Specifically, when using a thicker aluminum layer as the top metal layer to fill these dense vias, as shown in fig. 1, the topography effect of the IMD step locations is limited, which tends to cause voids (Void) phenomenon (areas shown as circles in fig. 1) inside the top metal layer. In the subsequent packaging process, particularly when the Polyimide (PI) layer is subjected to photolithography development, if the development is insufficient, PI material in the region that should be completely removed is likely to remain in the hollow position of the top metal. At the depressions or voids of the top layer metal, PI residues are present. Such PI residues may cause a significant increase in contact resistance between a subsequently formed rewiring layer (RDL) and the top metal pad. Abnormal increase of contact resistance can seriously interfere magneto-electric signal conversion of MEMS products, so that Noise (Noise) occurs to the products, and finally, the yield and reliability of chips are reduced. Therefore, there is a need for an optimized design and manufacturing method that can effectively eliminate PI residue caused by the top metal cavity while ensuring interlayer connection performance, thereby improving noise performance of AMR products. Disclosure of Invention The application provides a method for improving noise of a three-dimensional anisotropic magneto-resistive sensor product and the three-dimensional anisotropic magneto-resistive sensor product, which are used for solving the problems that holes are generated in a top metal layer due to densely arranged through holes below a bonding pad in the prior art, so that passivation protection layer residues are caused, contact resistance becomes large and product noise performance is deteriorated. The application provides a method for improving noise of a three-dimensional anisotropic magneto-resistive sensor product, which comprises the following steps of firstly, providing a substrate, wherein an interconnection layer is arranged on the substrate, and comprises a lower metal layer, a dielectric layer and a through hole formed in the dielectric layer; designing and forming a top metal layer, wherein the top metal layer is electrically connected with the lower metal layer through the through hole, and a pad area is arranged on the top metal layer; forming a passivation protection layer on the top metal layer, and carrying out opening treatment on the bonding pad area to expose part of the top metal layer for subsequent packaging connection; In the second step, an optimal design is performed on the layout of the through holes below the pad region, wherein the optimal design comprises controlling the distance between the through holes and the distribution density of the through holes in the pad region so as to reduce void defects generated when the top metal layer fills the through holes. Preferably, in the second step, the layout optimization