Search

JP-7856382-B2 - Injection molded solder head with improved sealing performance

JP7856382B2JP 7856382 B2JP7856382 B2JP 7856382B2JP-7856382-B2

Inventors

  • 羽田 さゆり
  • 青木 豊広
  • 久田 隆史
  • 山道 新太郎

Assignees

  • インターナショナル・ビジネス・マシーンズ・コーポレーション

Dates

Publication Date
20260511
Application Date
20221109
Priority Date
20211118

Claims (15)

  1. An apparatus for injecting solder material into via holes located on the upper surface of a wafer, wherein the apparatus: The injection head has a contact surface for contacting the upper surface of the wafer and at least one opening for injecting the solder material into the via hole through the injection head, To discharge gas from the via hole, the system includes an exhaust device connected to the injection head, The injection head has a chamfered portion on the edge of the contact surface that contacts the upper surface of the wafer, The contact surface includes a high average roughness region adjacent to the at least one opening and a low average roughness region surrounding the high average roughness region, wherein the low average roughness region has a lower average roughness than the high average roughness region. Device.
  2. The apparatus according to claim 1, wherein the chamfered portion is located on the outer circumference of the injection head.
  3. The apparatus according to claim 1, wherein the opening is slit-shaped, and the chamfered portion is positioned parallel to the at least one opening on the outer circumference of the injection head.
  4. The apparatus according to claim 1, wherein the chamfered portion is located on the trailing edge of the injection head in the forward direction of movement.
  5. The apparatus according to claim 1, wherein the chamfered portion of the chamfered area is composed of a straight edge.
  6. The apparatus according to claim 1, wherein the chamfered portion of the chamfered area includes a rounded portion.
  7. The apparatus according to claim 1, wherein the opening of the injection head includes a first opening and a second opening.
  8. The apparatus has at least one soldering bath, The apparatus according to claim 7, wherein the first opening and the second opening are connected to a common solder bath.
  9. The apparatus has a plurality of soldering baths, The apparatus according to claim 7, wherein the first opening and the second opening are each connected to different solder baths.
  10. The apparatus according to claim 7, wherein the solder material comprises a first solder material and a second solder material different from the first solder material, the first solder material is injected into the first opening, and the second solder material is injected into the second opening to form a solder bump comprising the first and second solder materials.
  11. The apparatus according to claim 7, wherein the area of the second opening is smaller than the area of the first opening.
  12. The apparatus according to claim 1, wherein the injection head includes at least one chamfered portion that contacts the at least one opening.
  13. A method for injecting solder material into via holes located on the upper surface of a wafer to form solder bumps, wherein the method is: The exhaust device discharges the gas from the via hole, An injection head, connected to the exhaust device and having a contact surface for contacting the upper surface of the wafer and at least one opening for solder injection to form the solder bump, wherein the contact surface includes a high average roughness region adjacent to the at least one opening and a low average roughness region surrounding the high average roughness region and having a lower average roughness than the high average roughness region, is used to inject the solder material into the via hole. A method comprising moving the injection head such that the chamfered edge of the injection head moves over the injected solder in order to bring the solder bump to an intended height.
  14. The opening of the injection head includes a first opening and a second opening, The method according to claim 13, wherein the solder material comprises a first solder material and a second solder material different from the first solder material, the first solder material is injected into the first opening and the second solder material is injected into the second opening to form a solder bump comprising the first solder material and the second solder material.
  15. The opening of the injection head includes a first opening and a second opening, The method according to claim 13 , wherein the injection includes injecting the solder material into the via hole through the first opening, and then injecting the solder material into the via hole through the second opening.

Description

This invention generally relates to integrated circuits, and more particularly to injection-molded solder heads having improved sealing performance. Injection-molded solder (IMS) technology is a solder bump technology used in the field of electronic packaging. In this technology, solder bumps are created by injecting molten solder into vias formed in the photoresist layer on a silicon wafer. One of the challenges of fine-pitch bumps in IMS is the variation in solder bump height. As the bump pitch decreases, the bump height also decreases. Therefore, even slight variations in height at the level of a few microns become significant. Variations in bump height can lead to electrical short circuits, poor solder wetting at interconnects, and other mechanical failures. The IMS head is made of rubber covered with a thin PTFE sheet. Surface analysis of the IMS head revealed that its surface roughness can reach several tens of microns at room temperature. Since the height of the solder bumps is determined by the scraping of molten solder by the IMS head surface, the surface roughness of the head directly affects the variation in solder bump height. Another challenge with fine-pitch IMS is missing solder within vias. Injecting molten solder into small holes becomes increasingly difficult due to the surface tension of the molten solder and the residual gas pressure within the via. One solution to this problem is to increase the injection pressure. However, increasing the injection pressure also requires increasing the load on the head to prevent solder leakage. Increasing the load improves the vacuum sealing, thus reducing the residual gas pressure within the vias. However, higher loads increase the friction between the head and the wafer, accelerating the deterioration of the head's rubber. According to an aspect of the present invention, an apparatus for injecting solder material into via holes located on the upper surface of a wafer is provided. The apparatus includes an injection head having a contact surface for contacting the upper surface of the wafer and at least one opening for injecting solder material into the via holes through the injection head. The apparatus further includes an exhaust device connected to the injection head for exhausting gas from the via holes. The injection head has a chamfered portion on the edge of the contact surface that contacts the upper surface of the wafer. According to another aspect of the present invention, an apparatus for injecting solder material into via holes located on the upper surface of a wafer is provided. The apparatus includes an injection head having a contact surface for contacting the upper surface of the wafer and a plurality of openings for injecting solder material from one or more solder baths of the injection head into the via holes. The apparatus further includes an exhaust device connected to the injection head for exhausting gas from the via holes. The injection head has a chamfered portion on the edge of the contact surface that contacts the upper surface of the wafer and at least one chamfered portion that contacts at least one of the plurality of openings. According to another aspect of the present invention, a method is provided for injecting solder material into via holes located on the upper surface of a wafer. The method includes exhausting gas from the via holes using an exhaust device. The method further includes injecting solder material into the via holes by an injection head connected to the exhaust device and having a contact surface for contacting the upper surface of the wafer and at least one opening for solder injection to form a solder bump. The method also includes moving the injection head so as to move the chamfered edge of the injection head over the solder bump to grind the solder bump to a desired height. According to another aspect of the present invention, a method is provided for injecting solder material into via holes located on the upper surface of a wafer. The method includes exhausting gas from the via holes using an exhaust device. The method further includes injecting the solder material into the via holes using an injection head connected to the exhaust device and having a contact surface for contacting the upper surface of the wafer and a plurality of openings for solder injection to form one or more solder bumps. The method also includes moving the injection head such that the chamfered edge of the injection head moves over one or more solder bumps to grind them down to a desired height. These and other features and advantages will become apparent from the following detailed description of exemplary embodiments, which should be read in conjunction with the accompanying drawings. The following description details preferred embodiments with reference to the following figures. This is a block diagram showing an exemplary computing device according to an embodiment of the present invention.This figure shows an exemplary