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Method for forming full IMCs structure welding spot through prefabricating IMCs bonding pad

A pad and solder joint technology is applied in the field of forming full IMCs structure solder joints by prefabricating IMCs pads, which can solve the problems of reducing the service life of electronic products, solder joints affecting service reliability, failure, etc., and achieving the effect of low cost

Active Publication Date: 2022-03-22
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

After the interconnection is completed, each solder joint has a unique crystal orientation, so it is inevitable that some solder joints will fail early during the use of electronic products due to the unfavorable orientation of β-Sn grains, thereby reducing the reliability of electronic products. service life
It can be seen that the grain orientation of solder joints will seriously affect its service reliability

Method used

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  • Method for forming full IMCs structure welding spot through prefabricating IMCs bonding pad
  • Method for forming full IMCs structure welding spot through prefabricating IMCs bonding pad
  • Method for forming full IMCs structure welding spot through prefabricating IMCs bonding pad

Examples

Experimental program
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Effect test

Embodiment 1

[0054] refer to Figure 1-3 , the present embodiment provides a method for forming a full IMCs structure solder joint by prefabricating IMCs pads, the method is realized through the following steps:

[0055] Step S1: Sn-Ag-Bi-In solder is printed on the glass plate through a sieve, the size of the sieve is 700 μm;

[0056] Step S2: Heat the missed-printed solder to form a solder ball with a size of 700 μm by hot air welding equipment (PACE ST325 in the United States, the same below), the remelting temperature is 245°C, the remelting time is 30s, and the furnace is cooled for 30s;

[0057] Step S3: successively use acetone and ethanol to clean the solder balls in an ultrasonic cleaner;

[0058] Step S4: Select solder balls that meet the size requirements under a stereo microscope for use;

[0059] Step S5: cleaning the surface of the printed circuit board with ethanol in an ultrasonic cleaner, and coating a layer of flux on the printed circuit board;

[0060] Step S6: Put th...

Embodiment 2

[0070] refer to Figure 1-3 , the present embodiment provides a method for forming a full IMCs structure solder joint by prefabricating IMCs pads, the method is realized through the following steps:

[0071] Step S1: Sn-Ag-Bi-In solder is printed on the glass plate through a sieve, the size of the sieve is 650 μm;

[0072] Step S2: Heat the missed-printed solder to form solder balls with a size of 650 μm by hot air soldering equipment (US PACE ST325, the same below), remelting temperature is 245°C, remelting time is 30s, and cools in the furnace for 30s;

[0073] Step S3: successively use acetone and ethanol to clean the solder balls in an ultrasonic cleaner;

[0074] Step S4: Select solder balls that meet the size requirements under a stereo microscope for use;

[0075] Step S5: cleaning the surface of the printed circuit board with ethanol in an ultrasonic cleaner, and coating a layer of flux on the printed circuit board;

[0076] Step S6: Put the prefabricated Sn-Ag-Bi-I...

Embodiment 3

[0086] refer to Figure 1-3 , the present embodiment provides a method for forming a full IMCs structure solder joint by prefabricating IMCs pads, the method is realized through the following steps:

[0087] Step S1: Sn-Ag-Bi-In solder is printed on the glass plate through a sieve, the size of the sieve is 700 μm;

[0088] Step S2: Heat the missed-printed solder to form solder balls with a size of 700 μm by hot air soldering equipment (US PACE ST325, the same below). The remelting temperature is 220°C, the remelting time is 40s, and the furnace is cooled for 40s;

[0089] Step S3: successively use acetone and ethanol to clean the solder balls in an ultrasonic cleaner;

[0090] Step S4: Select solder balls that meet the size requirements under a stereo microscope for use;

[0091] Step S5: cleaning the surface of the printed circuit board with ethanol in an ultrasonic cleaner, and coating a layer of flux on the printed circuit board;

[0092] Step S6: Put the prefabricated S...

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Abstract

The invention discloses a method for forming full-IMCs structure welding spots by prefabricating IMCs bonding pads, belongs to the field of material preparation and connection, is suitable for preparing full-IMCs miniature brazing butt joints and applied to reliability research of mechanics, thermotics and electrics of microelectronic connection, and is realized through the following steps: solder skip printing; heating and remelting the solder to form solder balls; selecting solder balls according to size requirements; placing the solder ball on a copper sheet on the surface of the printed circuit board, and heating, remelting and combining to form a bump structure; corroding the salient point structure; manufacturing two IMCs bonding pads; heating and remelting to combine the IMCs bonding pads; and grinding and finely polishing the welding spots of the IMCs bonding pad to finally obtain the full IMCs welding spots. The condition that the reliability of a welding spot is reduced due to anisotropy of Sn in the Sn-based welding flux can be avoided; the process is simple and low in cost. The method comprises the key steps that a prefabricated IMCs bonding pad is coated with welding flux for remelting and cooling, and it is determined that the welding spot component is IMCs through the EDS technology.

Description

technical field [0001] The invention relates to the field of material preparation and connection, in particular to a method for forming all-IMCs structural solder joints by prefabricating IMCs pads. Background technique [0002] Solder joints play the role of mechanical connection and electrical signal transmission in microelectronic interconnection. At present, the space of microelectronic packaging is reduced, the number of components is increased, and the heat generation of components is intensified; moreover, the current density borne by solder joints increases. Driven by dynamic and dynamic factors, the IMCs formed in the solder will grow or dissolve, causing the failure of the solder joint, thereby affecting the service life and reliability of electronic products. [0003] At present, the solder used in microelectronic interconnection is mainly Sn-based solder (containing more than 80% Sn), and existing studies have shown that Sn-based lead-free interconnect solder joi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K1/00B23K1/20B23K3/08B23K35/02B23K35/28
CPCB23K1/0016B23K1/203B23K1/206B23K3/085B23K35/0222B23K35/282
Inventor 汉晶孟洲郭福马立民晋学轮李子萱陈玉章贾强周炜王乙舒
Owner BEIJING UNIV OF TECH