US-12628677-B2 - Packages with thick RDLs and thin RDLs stacked alternatingly

US12628677B2US 12628677 B2US12628677 B2US 12628677B2US-12628677-B2

Abstract

A method includes forming a plurality of dielectric layers, which processes include forming a first plurality of dielectric layers having first thicknesses, and forming a second plurality of dielectric layers having second thicknesses smaller than the first thicknesses. The first plurality of dielectric layers and the second plurality of dielectric layers are laid out alternatingly. The method further includes forming a plurality of redistribution lines connected to form a conductive path, which processes include forming a first plurality of redistribution lines, each being in one of the first plurality of dielectric layers, and forming a second plurality of redistribution lines, each being in one of the second plurality of dielectric layers.

Inventors

Po-Yuan TENG
Kuo Lung Pan
YU-CHIA LAI
Tin-Hao Kuo
Hao-Yi Tsai
Chen-Hua Yu

Assignees

TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20240628

Claims (20)

1 . A package comprising: a first plurality of dielectric layers; a second plurality of dielectric layers, wherein the first plurality of dielectric layers and the second plurality of dielectric layers are positioned alternatingly, wherein each of the first plurality of dielectric layers physically contacts an overlying one and an underlying one of the second plurality of dielectric layers; a first plurality of redistribution layers, each in one of the first plurality of dielectric layers; and a second plurality of redistribution layers, each in one of the second plurality of dielectric layers, wherein the first plurality of redistribution layers are thinner than the second plurality of redistribution layers.
2 . The package of claim 1 , wherein the first plurality of dielectric layers have first thicknesses, and wherein the second plurality of dielectric layers have second thicknesses greater than the first thicknesses.
3 . The package of claim 2 wherein ratios of the second thicknesses to the first thicknesses are greater than about 1.5.
4 . The package of claim 1 , wherein the first plurality of redistribution layers are electromagnetic shielding layers, and the second plurality of redistribution layers are signal routing layers for laterally routing signals.
5 . The package of claim 3 further comprising: a metal pad in one of the first plurality of redistribution layers; a first metal line in a first layer of the second plurality of redistribution layers, wherein the first layer is overlying the metal pad; and a second metal line in a second layer of the second plurality of redistribution layers, wherein the second layer is underlying the metal pad, and wherein the first metal line is electrically connected to the second metal line through the metal pad.
6 . The package of claim 1 , wherein the first plurality of dielectric layers are formed of a homogeneous polymer, and wherein the second plurality of dielectric layers are molding compounds.
7 . The package of claim 1 , wherein a longest line in the first plurality of redistribution layers has a length, and a plurality of redistribution lines in the second plurality of redistribution layers are longer than the longest line in the first plurality of redistribution layers.
8 . The package of claim 1 , wherein the second plurality of dielectric layers comprise base materials and filler particles in the base materials, and the filler particles adjacent to top surfaces of the second plurality of dielectric layers comprise partial particles.
9 . The package of claim 8 , wherein the partial particles have top surfaces coplanar with top surfaces of respective ones of the second plurality of dielectric layers.
10 . The package of claim 8 , wherein the filler particles adjacent to bottom surfaces of the second plurality of dielectric layers are spherical particles.
11 . The package of claim 1 further comprising a first plurality of vias in the second plurality of dielectric layers, wherein the first plurality of vias form distinguishable interfaces with overlying ones of the first plurality of redistribution layers and underlying ones of the second plurality of redistribution layers.
12 . The package of claim 11 further comprising a second plurality of vias in the first plurality of dielectric layers, wherein the second plurality of vias share common seed layers with respective overlying ones of the second plurality of redistribution layers.
13 . A package comprising: a plurality of dielectric layers comprising: a first plurality of dielectric layers comprising a same first dielectric material; a second plurality of dielectric layers comprising a same second dielectric material different from the same first dielectric material, wherein the first plurality of dielectric layers and the second plurality of dielectric layers are located alternatingly; and a plurality of conductive features connected to form a conductive path, wherein the plurality of conductive features comprise: a first plurality of horizontal redistribution lines, each being in one of the first plurality of dielectric layers; a second plurality of horizontal redistribution lines, each being in one of the second plurality of dielectric layers, wherein the first plurality of horizontal redistribution lines are thicker than the second plurality of horizontal redistribution lines; a first plurality of vias, each being in one of the first plurality of dielectric layers and contacting a respective underlying one of the first plurality of horizontal redistribution lines; and a second plurality of vias, each being in one of the second plurality of dielectric layers and contacting a respective underlying one of the second plurality of horizontal redistribution lines.
14 . The package of claim 13 , wherein the first plurality of dielectric layers are thicker than the second plurality of dielectric layers.
15 . The package of claim 13 , wherein the first plurality of vias form distinguishable interfaces with overlying ones of the second plurality of horizontal redistribution lines.
16 . The package of claim 15 , wherein the second plurality of vias are continuously connected to overlying ones of the first plurality of horizontal redistribution lines without distinguishable interfaces in between.
17 . The package of claim 13 , wherein the first plurality of vias comprise first sidewalls, and the second plurality of vias comprise second sidewalls more slanted than the first sidewalls.
18 . A package comprising: a first plurality of dielectric layers formed of a first dielectric material; a second plurality of dielectric layers formed of a second dielectric material different from the first dielectric material, wherein the first plurality of dielectric layers are between, and are in contact with, respective overlying ones and underlying ones of the second plurality of dielectric layers; a first plurality of redistribution lines, wherein trace portions of the first plurality of redistribution lines are in the first plurality of dielectric layers, and have first thicknesses; and a second plurality of redistribution lines, each comprising a trace portion and a via portion underlying the trace portion, wherein the trace portions of the second plurality of redistribution lines are in the second plurality of dielectric layers, and have second thicknesses greater than the first thicknesses.
19 . The package of claim 18 , wherein the second plurality of redistribution lines further comprise via portions continuously connected to the trace portions of the second plurality of redistribution lines with no distinguishable interface in between.
20 . The package of claim 18 , wherein the via portions of the second plurality of redistribution lines are in the first plurality of dielectric layers.

Description

PRIORITY CLAIM AND CROSS-REFERENCE This application is a continuation of U.S. patent application Ser. No. 17/814,730, entitled “Packages with Thick RDLs and Thin RDLs Stacked Alternatingly,” filed on Jul. 25, 2022, which is a divisional of U.S. patent application Ser. No. 16/909,517, entitled “Packages with Thick RDLs and Thin RDLs Stacked Alternatingly,” filed on Jun. 23, 2020, now U.S. Pat. No. 11,508,665, issued Nov. 22, 2022, which applications are incorporated herein by reference. This application relates to commonly-assigned U.S. patent application Ser. No. 16/656,642, filed Oct. 18, 2019, and entitled “Hybrid Dielectric Scheme in Packages,” which application is hereby incorporated herein by reference. BACKGROUND With the evolving of semiconductor technologies, some semiconductor chips/dies are becoming increasingly smaller. In the meantime, more functions need to be integrated into the semiconductor dies, which also cause other semiconductor dies and the resulting packages to become increasingly larger. Redistribution lines are formed in the package substrates for routing power and signals in packages. With the packages become increasingly lager to accommodate more functions such Artificial Intelligence (AI) applications, the redistribution lines become very long, sometimes as long as tens of millimeters. The long redistribution lines have high resistance values, and cause significant insertion loss, especially for high-speed signals. BRIEF DESCRIPTION OF THE DRAWINGS Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. FIGS. 1 through 22 illustrate the cross-sectional views of intermediate stages in the formation of packages in accordance with some embodiments. FIG. 23 illustrates a plane view of example layouts of neighboring thick RDLs and thin RDLs in accordance with some embodiments. FIGS. 24 and 25 illustrate the cross-sectional views of some package in accordance with some embodiments. FIG. 26 illustrates an amplified view of a region in a package in accordance with some embodiments. FIG. 27 illustrates a process flow for forming a package in accordance with some embodiments. DETAILED DESCRIPTION The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, spatially relative terms, such as “underlying,” “below,” “lower,” “overlying,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. A package with thick dielectric layers and thick Redistribution Lines (RDLs) laid out alternatingly with thin dielectric layers and thin RDLs and the method of forming the same are provided in accordance with some embodiments. The intermediate stages in the formation process are also illustrated. Embodiments discussed herein are to provide examples to enable making or using the subject matter of this disclosure, and a person having ordinary skill in the art will readily understand modifications that can be made while remaining within contemplated scopes of different embodiments. Throughout the various views and illustrative embodiments, like reference numbers are used to designate like elements. Although method embodiments may be discussed as being performed in a particular order, other method embodiments may be performed in any logical order. FIGS. 1 through 22 illustrate the cross-sectional views of intermediate stages in the formation